Method of producing acrolein, acrylic acid or mixture thereof from propane

FIELD: chemistry.

SUBSTANCE: according to method A) an input stream of the reaction gaseous mixture A is fed into the input of the first reaction zone A, where the input stream is obtained by merging at least four different gaseous initial streams 1, 2, 3 and 4, where the gaseous initial streams 1 and 2 contain propane, gaseous initial stream 4 is molecular hydrogen and gaseous initial stream 3 is fresh propane, the input stream of the reaction gaseous mixture A is passed at least through one catalyst layer of the first reaction zone A on which, if needed, when feeding other gaseous streams, as a result of heterogeneous catalytic partial dehydrogenation of propane, a stream of products of gaseous mixture A forms, which contains propane and propylene, the stream of products of gaseous mixture A comes out of the first reaction zone A through the corresponding outlet, while splitting said stream into two partial streams 1 and 2 of products of the gaseous mixture A with identical composition, and the partial stream 1 of products of the gaseous mixture A is returned to the first reaction zone A as the gaseous initial stream 1, the partial stream 2 of products of the gaseous mixture A, if needed, is directed to the first separation zone A, in which a portion or more of components contained therein, which are different from propane and propylene, are separated, as a result of which a stream of products of gaseous mixture A' which contains propane and propylene, B) partial stream 2 of products of the gaseous mixture A or a stream of products of gaseous mixture A' is used in a second reaction zone B for supplying at least one oxidation reactor, in which propylene contained in the partial stream 2 of products of gaseous mixture A or in the stream of products of gaseous mixture A' undergoes selective heterogeneously catalysed partial gas-phase oxidation with molecular oxygen to obtain a stream of products of a gaseous mixture B, which contains acrolein, acrylic acid or mixture thereof as the desired product, unconverted propane and, if needed, unconverted propylene, as well as molecular oxygen, the stream of products of gaseous mixture B comes out of reaction zone B, the desired product contained in separation zone B is separated in said separation zone B and at least a portion of residual gas formed after separation and containing unconverted propane, molecular oxygen and, if needed, unconverted propylene, is returned to reaction zone A as gaseous initial stream 2. Gaseous initial streams 2, 3 and 4 as well as, if needed, additional gaseous initial streams different from the gaseous initial stream 1, are merged into a gaseous stream of the working mixture, after which, using this gaseous stream of the working mixture as the working stream, a jet pump is activated, said pump having a nozzle, a mixing section, a diffuser and a suction inlet. Movement of the working stream which is throttled through the nozzle, the mixing section and the diffuser to the input of the first reaction zone A, as well as the suction effect of the suction inlet takes place in the direction of outlet of the stream of products of gaseous mixture A from the first reaction zone A. The pressure drop created in the suction nozzle with splitting of the stream of products of the gaseous mixture A into two partial streams 1 and 2 results in suction of the partial stream 1 of products of the gaseous mixture A, its movement through the diffuser with simultaneous mixture with the working stream on the mixing section and inlet of the formed reaction stream of gaseous mixture A at its inlet point into the first reaction zone A, characterised by that a gaseous initial mixed stream is formed first by merging in random sequence gaseous initial streams 2 and 3, as well as, if needed, additional gaseous initial streams different from gaseous initial streams 1 and 4, and only after that the gaseous initial stream 4 is added to the formed gaseous initial mixed stream to obtain a gaseous mixed working stream.

EFFECT: used of present method reduces heat loss and prevents a drop in degree of dehydrogenation when producing acrolein, acrylic acid or mixture thereof from propane.

7 cl, 4 ex, 4 dwg

 

The present invention relates to a method of producing acrolein, acrylic acid, or a mixture thereof from propane, in accordance with which the

(A) for entry into the first reaction zone And serves stream source of the reaction gas mixture As obtained by the Association, at least four differing from each gas source flows 1, 2, 3 and 4, and a gaseous source streams 1, 2 and 3 contain propane, gaseous source stream 4 is molecular hydrogen and a gaseous source stream 3 is fresh propane,

stream source of the reaction gas mixture And pass at least one catalyst bed of the first reaction zone And which the heterogeneously catalyzed partial propane dehydrogenation carried out, if necessary, when applying other gas flows, is formed a flow of gas mixture of reaction products containing propane and propylene,

the flow of the gas mixture of the reaction products And is removed from the first reaction zone And through the corresponding release, thus dividing it into two partial stream 1 and 2 of the same composition, and a partial stream 1 gas mixture of reaction products And in accordance with the first mode of recirculation back into the first reaction zone as a gaseous source stream 1,

partial flow 2 gas mixture product is tov reaction And, if necessary, send in the first separation zone A, in which we distinguish a partial or more components contained in it, different from propane and propylene, leaving the flow of the gas mixture of the reaction products And'containing propane and propylene,

partial flow 2 gas mixture of reaction products And or flow of the gas mixture of the reaction products As' used in the second reaction zone to supply at least one oxidation reactor, which is contained in these threads propylene is subjected to a selective heterogeneously catalyzed partial gas-phase oxidation with molecular oxygen to produce a flow of gas mixture of reaction products, consisting of acrolein, acrylic acid or mixtures thereof as the target product, neprevyshenie propane and, if necessary, neprevyshenie propylene, and the excess of molecular oxygen,

the flow of the gas mixture of the reaction products In the output from the reaction zone Into the second separation zone To produce therein a target product and at least a partial amount of the resultant residual gas containing neprevyshenie propane, molecular oxygen and, if necessary, neprevyshenie propylene, and in accordance with the second mode of recirculation back into reactio the reduction zone And for use as a gaseous source stream 2,

moreover, the gaseous source streams 2, 3 and 4, and, if necessary, additional gas source flows that differ from the gaseous source stream 1, merge into the flow of gaseous mixture, which as workflow activates the jet pump comprising a nozzle, a mixing section, diffuser and suction tube,

and moving drosselweg nozzle of the working gas through the mixing section and diffuser in place entry in the first reaction zone A, and the suction action of the suction nozzle directed toward the issue of flow of the gas mixture of the reaction products And from the first reaction zone And

and thanks created in the suction pipe of the vacuum separation of the flow of the gas mixture of the reaction products And the two partial stream 1 and 2 is the absorption of a partial stream 1 gas mixture of reaction products And its movement through the diffuser while mixing with a work flow in the mixing section and release the resulting flow of the reaction gas mixture And place of its entry into the first reaction zone A.

Acrylic acid as a product of partial oxidation of propylene is an important monomer, which in itself or in the form of the corresponding complex alilovic esters used in the example, for the production of adhesives or super absorbent water polymers (see, for example, international application WO 02/055469 and WO 03/078378). Acrolein is an important intermediate product that is used, for example, for the synthesis of glutaric aldehyde, methionine, folic acid and acrylic acid.

Known methods of synthesis of acrolein and/or acrylic acid, in accordance with which the partial heterogeneously catalyzed dehydrogenation of propane propylene get that in the presence of neprevyshenie (inert) propane, which is a component subject to partial oxidation of the mixture, is subjected to partial heterogeneously catalyzed gas-phase oxidation with molecular oxygen leading to the formation of mixtures of products containing acrolein and/or acrylic acid (see, for example, German patent application DE-A 10245585 and cited in her art).

Unlike carried out in the presence of oxygen exothermic heterogeneously catalyzed oxidative dehydrogenation with no intermediate formation of free hydrogen (hydrogen, open from subject to dehydrogenation of propane, directly forms the water), respectively, in which free hydrogen cannot be detected analytically, under the heterogeneously catalyzed digidrirovanny the eat in accordance with the present description shall be interpreted to mean "traditional" dehydrogenation, which is in contrast to the oxidative dehydrogenation is an endothermic heat effect (subsequent stage heterogeneously catalyzed dehydrogenation may be exothermic combustion of hydrogen) and in which there is at least intermediate formation of free molecular hydrogen. The implementation of such a process typically requires the use of other reaction conditions and other catalysts than oxidative dehydrogenation.

In accordance with the foregoing, under fresh propane in the present description mean propane not involved neither in the dehydrogenation in reaction zone A, or in partial oxidation of propylene to acrolein and/or acrylic acid in the reaction zone Century. Like the propane is preferably generally did not participate in any chemical reactions. Typically, it is introduced into the reaction system in the form of crude propane, which preferably conforms to the specifications described in the German patent applications DE-A 10246119 and DE-A 10245585, and usually also contains minor amounts different from propane components. Such crude propane can be obtained by a method described, for example, in German patent application DE-A 102005022798. The crude propane typically contains at least ≥90 wt.%, preferably, at least, ≥95 wt.% propane.

is defined above, related to the prior art, typically implement in the recirculation mode, in accordance with which at least a partial amount of residual gas, which contains neprevyshenie propane, molecular oxygen and, if necessary, neprevyshenie propylene, and remains after separation of the target product from a mixture of partial oxidation products containing neprevyshenie propane, molecular oxygen and, if necessary, neprevyshenie propylene, return to the zone heterogeneously catalyzed dehydrogenation.

With this as a starting reaction gas mixture (for example, in German patent applications DE-A 102004032129 and DE-A 102005013039) in the area heterogeneously catalyzed dehydrogenation of propane to propylene was offered to direct the mixture of water vapor, fresh propane and above the recirculated gas. Moreover expedient option involves the implementation of the heterogeneously catalyzed propane dehydrogenation in a deck reactor, the optimum location of shelves which corresponds to successive radial or axial arrangement. In such shelf reactor is advisable to use a stationary catalyst layers. In accordance with a preferred variant of such a reactor is equipped with three shelves with catalyst. According to the prior art heterogeneous ka is lisaruume partial dehydrogenation of propane is recommended in autothermal mode. For the implementation of the autothermal mode to passed through the first catalyst bed of the reaction gas mixture between the (fixed) catalyst, following the first (fixed) catalyst bed to add a limited amount of molecular oxygen (such as air). Thanks this is usually catalyzed by the catalytic dehydrogenation of a limited combustion of molecular hydrogen, which is formed in the process heterogeneously catalyzed dehydrogenation of propane (and, if necessary, the combustion of a minimum number of propane), and the corresponding exothermic heat effect mainly allows to maintain the desired temperature dehydrogenation (adiabatic reactor).

According to comparative examples 1, 3 and 4, described in the German patent application DE-A 102004032129, and according to the example embodiment of the invention shown in the German patent application DE-A 102005010111, partial heterogeneously catalyzed dehydrogenation of propane to the above types implement shelf in the dehydrogenation reactor (containing three shelves with layers of catalyst) through three series-connected tubular reactors for the dehydrogenation. However, according to the above comparative examples and example implementation of izobreteniyami series connection of tubular reactors may be used as shown in figure 1 and 2 (adiabatic) shelf reactor (with three located on the respective shelves stationary catalyst).

As shown in figure 1, the reaction mixture passes through the bulk layers of the catalyst (2) shelf reactor in the direction from outside to inside. In contrast, the reaction mixture passes through the bulk layers of the catalyst (2), loaded is shown in figure 2 shelf reactor, from the inside outwards. Figures 1 and 2 position (1) identified the source of the reaction gas mixture, the positions (3) supply air and the positions (4) mixing elements.

Suitable are the following parameters of the reactor (in terms of flow rate are contained in the source of the reaction gas mixture of propane, comprising 72280 kg/h, and the total air flow, comprising 3496 kg/h). The reactor according to Figure 1

The total mass loaded in the reactor catalyst, t30
The mass of catalyst on each of the shelves, t10
The height of the bulk catalyst layer on each of the shelves, m5,47
The apparent density of the layer of catalyst, kg/m31200
The inner radius of the bulk catalyst, m1,05
the external radius of the bulk catalyst, m1,26
The volume of the bulk catalyst layer on each of the shelves, m38,33
The diameter of the supply pipe, m1,4
The diameter of the reactor, m3,2
The height of the cylindrical part of the reactor, m21
The number of mixing elements2
The absolute pressure of the source of the reaction gas mixture, bar3,1

Thus it is necessary to use a catalyst of the above corresponding comparative example or embodiment of the invention. The same applies to the reaction temperature and the composition of the starting reaction gas mixture.

Suitable structural material, preferably used for the manufacture of all nodes in the reactor, is a special silicon steel or, for example, steel 1.4841.

The reactor according to Figure 2

The total mass loaded in the reactor catalyst, t30
The mass was pushing the congestion on each of the shelves, t10
The height of the bulk catalyst layer on each of the shelves, m4,84
The apparent density of the layer of catalyst, kg/m31200
The inner radius of the bulk catalyst, m1,2
The outer radius of the bulk catalyst, m1,41
The volume of the bulk catalyst layer on each of the shelves, m38,33
The diameter of the supply pipe, m1,4
The diameter of the reactor, m3,4
The height of the cylindrical part of the reactor, m19
The number of mixing elements2
The absolute pressure of the source of the reaction gas mixture,3,1
bar

Thus it is necessary to use a catalyst of the above corresponding comparative example or embodiment, the image is placed. The same applies to the reaction temperature and the composition of the starting reaction gas mixture. Suitable structural material, preferably used for the manufacture of all nodes in the reactor, is a special silicon steel or, for example, steel 1.4841.

Thus heterogeneously catalyzed partial dehydrogenation of propane, it is advisable to carry out using the catalyst distributed on three shelves of the reactor mainly so that the degree of conversion of propane in a single passage through the reactor was about 20 mol.%. The specified conversion of propane corresponds to the selectivity of the formation of propylene, as a rule, component 90 mol.%. With increasing duration of operation of the catalyst, the maximum conversion of propane on separate shelves of the reactor is displaced in the direction of pass of the reaction gas mixture from the first shelf to the last. The catalyst is subjected to regeneration, as a rule, before the specified maximum will shift to the third shelf. Regeneration of the catalyst preferably should be done in time, which corresponds to achieving the same degree of coking of the catalyst on the shelves of the reactor.

The optimal total consumption of propane and propylene, is passed through the total number loaded into R. the actor (that are on the shelves) catalyst, when the above heterogeneously catalyzed partial dehydrogenation of propane in the range of from 500 to 20,000 nl/l·h (in a typical case, from 1500 to 2500 nl/l·h). The maximum temperature inside each of the fixed layers of the dehydrogenation catalyst is preferably from 500 to 600°C. In a particularly preferred embodiment, the above stage heterogeneously catalyzed partial dehydrogenation of propane coming shelf in the reactor, the reaction gas mixture consists only of fresh propane and gas recirculated from the stage partial oxidation, which contains formed at this stage, the water vapor in sufficient quantity to provide a satisfactory service life of the catalyst in the dehydrogenation of propane. Thus, the above comparative examples and example implementation of the invention can be implemented in the described shelf dehydrogenation reactors and also in case of refusal from the addition of external water vapor. With regard to other conditions of dehydrogenation, just the appropriate information given in the German patent applications DE-A 102005009885, DE-A 102005010111, DE-A 102005009891, DE-A 102005013039 and DE-A 102004032129. As mentioned documents, in this application under the flow passed through the catalyst bed of the reaction gas mixture sublattice is somewhat the flow of the reaction gas mixture through a liter of catalyst layer (for example, stationary layer of catalyst per hour, expressed in normal litres (nl), that is, in litres, reduced to standard conditions (0°C, 1 bar). However, presented in this way the flow can also refer to only one of the components of the reaction gas mixture. In this case we are talking about the consumption of this component in normal liters per hour through a liter of catalyst layer (loaded into the reactor, inert materials when calculating the volume of the fixed catalyst layer does not take into account).

The flow rate entering the reactor, the source of the reaction gas can also be attributed only to contained in one layer of the catalyst, which may be diluted with inert material (in this case specifically indicate the number of catalyst).

The disadvantage of the above method according to the prior art is that almost all of the catalysts for the dehydrogenation of propane simultaneously catalyze occurs in the presence of molecular oxygen the combustion of propane and propylene (that is, the complete oxidation of these hydrocarbons to carbon oxides and water vapor), and the gas recycled from the stage partial oxidation stage heterogeneously catalyzed partial dehydrogenation of propane, usually already contains molecular oxygen. The presence of molecular oxygen in the recirculated gas also decided the Leno fact, that ensure longer service life of the catalyst for heterogeneously catalyzed partial oxidation with molecular oxygen at a stage of partial oxidation is usually used in excess compared with the stoichiometric quantity. Catalyzed combustion of propane and/or propylene contained in the incoming stage dehydrogenation of the original reaction mixture, in the presence of a specified excess of molecular oxygen leads to a decrease in the selectivity of formation of propylene on stage heterogeneously catalyzed partial dehydrogenation of propane.

In this regard, earlier it was suggested in the implementation of the multistage synthesis of acrolein and/or acrylic acid from propane (see German patent application DE-A 10211275) to perform the heterogeneously catalyzed partial dehydrogenation of propane by a method comprising separating the output from the dehydrogenation zone of the target product of two partial stream of identical composition, one of which is directed to a stage of partial oxidation, while the other partial flow return on stage dehydrogenation as a component of the source of the reaction gas mixture. Present in this partial recirculated gas flow of molecular hydrogen formed during the dehydrogenation of propane, on nom case performs the function of protection is contained in the original reaction gas mixture of propane and optionally, the propylene from the combustion caused by the interaction of these hydrocarbons are simultaneously present in the source gas with molecular oxygen. This protection is based on the preferential combustion of molecular hydrogen (water), usually heterogeneously catalyzed by catalytic dehydrogenation, which is kinetically more favorable than complete combustion of propane and/or propylene.

From German patent application DE-A 10211275 know about dehydration with recirculation of gas sold in accordance with the principle of the jet pump (this method is also called loop technology). In this application we also consider the possibility of adding to used for propane dehydrogenation reaction gas mixture additional molecular hydrogen. However, the publication does not discuss the need for sequencing dosing of molecular hydrogen in a work flow jet pump.

In accordance with the German patent applications DE-A 102004032129 and DE-A 102005013039 containing molecular oxygen gas produced by heterogeneously catalyzed partial oxidation, it is proposed to return to the source of the reaction gas mixture is directed to the heterogeneously catalyzed partial dehydrogenation propanol is preferred recirculation containing molecular oxygen gas in the specified reaction gas mixture, exercised only upon reaching a certain degree of conversion of propane at the stage of dehydrogenation. In the German patent application DE-A 102004032129 before the specified recycling are also encouraged to add to sent to the dehydrogenation reaction gas mixture additional external molecular hydrogen. Moreover, in the cited application is recommended for propane dehydrogenation and loop technology. The worker thread is exclusively gas recirculated from the stage partial oxidation stage dehydrogenation.

However, this technology has the drawback consisting in the fact that from the stage dehydrogenation stage partial oxidation is more significant partial quantity dispensed outside of molecular hydrogen without prior use of its protective capabilities in comparison with the amount of molecular hydrogen supplied as a component of a gaseous mixture of reaction products. In addition, the jet pump increases the partial pressure of the mixture of products of partial dehydrogenation, and at the stage of partial oxidation carry out the reduction created increased pressure. However, to compensate for what is happening on stage partial oxidation pressure loss before the proceedings in any case which usually must be performed additional compression of the corresponding source of the reaction gas mixture through a separate compressor. As a rule, under pressure are also converting partial flow 2 gas mixture of reaction products And the flow of the gas mixture of the reaction products And'. Given this, the above pressure increase through the jet pump seems malecelebrities.

In this regard, in the example in the German patent application DE-A 102005009885 example II it is recommended to use a loopback technology, according to which the source of the reaction gas mixture intended for the implementation of the heterogeneously catalyzed partial dehydrogenation of propane, consists of recirculated from the stage partial oxidation gas, fresh propane, external molecular hydrogen, a minimum number of external water vapor and gas recirculated directly from the stage dehydrogenation (you can also refuse the use of external water vapor). As a working flow of a mixture consisting of fresh propane, external molecular hydrogen recycled from the stage partial oxidation gas and the external water vapor. In the cited publication no information regarding be following the sequence of the dosage form workflow components. The reason for the lack of such information is that at the moment of creation of the relevant experience of the first installation of special steel, the authors did not have any data regarding the observance of a special sequence of batching. However, over time it was found that minor rust on the surface is made of a special or ordinary steel (that is, in the General case of steel) nodes of the experimental setup, formed during its long operation, catalyzes occurs in the presence of molecular oxygen the combustion of molecular hydrogen. This circumstance should be regarded as a disadvantage, since at least part of the heat of combustion is not where it would be necessary, i.e. in the area of the endothermic dehydrogenation of propane. On the contrary, at least part of the emitted during the combustion of the hydrogen heat does not make a useful contribution to the achievement of the desired adiabatic mode dehydrogenation, as the creation of an ideal adiabatic device is unrealizable task. This either requires summing external heat, followed by leakage of unwanted process of cracking hydrocarbons used, usually occurring on the heat transfer surfaces, or leads to a significant reduction in the degree of dehydrogenation. Both the phenomenon should be considered as disadvantages.

The present invention was based on the task to provide an improved method of producing acrolein, acrylic acid or mixtures of isopropane, which does not suffer from the above disadvantages or they are inherent only to a small extent.

In line with this, a method was found of obtaining acrolein, acrylic acid, or a mixture thereof from propane, according to which

(A) for entry into the first reaction zone And serves stream source of the reaction gas mixture As obtained by the Association, at least four differing from each gas source flows 1, 2, 3 and 4, and a gaseous source streams 1, 2 and 3 contain propane, gaseous source stream 4 is molecular hydrogen and a gaseous source stream 3 is fresh propane,

stream source of the reaction gas mixture And pass at least one catalyst bed of the first reaction zone And which the heterogeneously catalyzed partial propane dehydrogenation carried out, if necessary, when applying other gas flows, is formed a flow of gas mixture of reaction products containing propane and propylene,

the flow of the gas mixture of the reaction products And is removed from the first reaction zone And through the corresponding release, thus dividing it into two partial stream 1 and 2 of the same composition, and a partial stream 1 gas mixture of reaction products And in accordance with the first recirculation mode return in the first reaction the second zone as a gaseous source stream 1,

partial flow 2 gas mixture of reaction products And, if necessary, send in the first separation zone A, in which we distinguish a partial or more components contained in it, different from propane and propylene, leaving the flow of the gas mixture of the reaction products And'containing propane and propylene,

partial flow 2 gas mixture of reaction products And or flow of the gas mixture of the reaction products As' used in the second reaction zone to supply at least one oxidation reactor, which is contained in these threads propylene is subjected to a selective heterogeneously catalyzed partial gas-phase oxidation with molecular oxygen to produce a flow of gas mixture of reaction products, consisting of acrolein, acrylic acid or mixtures thereof as the target product, neprevyshenie propane and, if necessary, neprevyshenie propylene, and the excess of molecular oxygen,

the flow of the gas mixture of the reaction products In the output from the reaction zone Into the second separation zone To produce therein a target product and at least a partial amount of the resultant residual gas containing neprevyshenie propane, molecular oxygen and, if necessary, neprevyshenie propylene, and in compliance and with the second recirculation mode return to the reaction zone for use as a gaseous source stream 2,

moreover, the gaseous source streams 2, 3 and 4, and, if necessary, additional gas source flows that differ from the gaseous source stream 1, merge into the flow of gaseous mixture, which as workflow activates the jet pump comprising a nozzle, a mixing section, diffuser and suction tube,

and moving drosselweg nozzle of the working gas through the mixing section and diffuser in place entry in the first reaction zone A, and the suction action of the suction nozzle directed toward the issue of flow of the gas mixture of the reaction products And from the first reaction zone And

and thanks created in the suction pipe of the vacuum separation of the flow of the gas mixture of the reaction products And the two partial stream 1 and 2 is the absorption of a partial stream 1 gas mixture of reaction products And its movement through the diffuser while mixing with a work flow in the mixing section and release the resulting flow of the reaction gas mixture And place of its entry into the first reaction zone A.

wherein the first gaseous form of the original mixed stream, combining in an arbitrary sequence gaseous source streams 2 and 3, and, if necessary, to anitelea gas source flows, different from gas source flows 1 and 4, and only after that to the generated gaseous source mixed flow type gaseous source stream 4, receiving mixed gaseous working stream.

Proposed in the invention method to different parts may be implemented in accordance with the technology described in European patent application EP-A 117146, application for U.S. patent US-A 3161670, German patent application DE-A 3313573, international application WO 01/96270, and German patent applications DE-A 10316039, DE-A 102005013039, DE-A 102004032129, DE-A 10211275, DE-A 10245585, DE-A 102005009891, DE-A 102005010111, DE-A 102005022798 and DE-A 102005009885.

According to the invention the addition of gaseous source stream 4 to the gaseous source mixed stream (with the formation of a mixed workflow) is preferably carried out within the shortest period of time. In addition, adding a gaseous source stream 4 to the gaseous source mixed flow, followed by formation of a mixed workflow carried out so that the time interval between the moment of formation of a mixed workflow and achieve flow of the source of the reaction gas mixture And the first layer of catalyst in the dehydrogenation reaction zone And (in the direction of transmission), mainly accounted for no more than 30 with the Kund, no more than 20 or 10 seconds, preferably not more than 7 seconds, especially preferably not more than 5 seconds, even more preferably not more than 3 seconds and best of all no more than 1 second, respectively, 0.5, or 0.1 seconds.

In accordance with the proposed invention is a method for separation of the target product contained in the flow of the gas mixture of the reaction products, it is in principle possible to use any known prior art method. The main feature of such methods is that thanks to the implementation of, for example, absorption and/or condensation events target product is transferred from the gaseous phase to the condensed phase. The absorbent can be used, for example, water, an aqueous solution and/or an organic solvent. As a result of this "condensation" of the target product usually remains a challenge in condensed phase residual gas, which contains relatively difficult condensable components of the gas flow of the mixture of reaction products Century. Usually we are talking primarily about those components, the boiling point of which at normal pressure (1 bar) is ≤-30°C (their total content in the residual gas is typically ≥70 vol.%, often ≥80% vol. and in most cases, ≥90%). Such components primarily include neprilysin the th propane, remaining in the stream of gaseous mixture of reaction products In excess of molecular oxygen, and optionally neprevyshenie propylene. The residual gas is typically further comprises an inert diluting gases, such as nitrogen, carbon dioxide, noble gases (helium, neon, argon, and so forth), carbon monoxide, and minor amounts of acrylic acid, acrolein and/or water (water vapor content in the residual gas can reach 25%, often 20 or 10 vol.%, and in most cases is less than 10 or 5 vol.%). The above residual gas usually forms the principal amount formed in the separation zone In the residual gas, which is typically at least 80%, at least 90%or at least 95%, or more (in terms of the contained quantity of propane), and therefore in the present description it is sometimes referred to as the main residual gas.

According to the invention, at least a partial quantity of the specified residual gas (the main residual gas)containing neprevyshenie propane, molecular oxygen and, if necessary, neprevyshenie propylene, the corresponding recirculation circuit generally return to the reaction zone and used as a gaseous source potoka. According to the invention in most cases it is advisable to return to the reaction zone and to use as a gaseous source stream 2 the whole amount of such residual gas.

First of all, if condensation of the target product are carried out by absorption with an organic solvent in the separation zone, typically formed of at least one secondary residual gas containing neprevyshenie propane and, if necessary, neprevyshenie propylene (the number of secondary residual gas in terms of the contained propane is usually significantly less compared to the number of main residual gas). The formation of secondary residual gas due to the fact that the condensed phase to a certain extent also absorbs neprevyshenie propane and, if necessary, neprevyshenie propylene.

Subsequent selection of the target product from the condensed phase, which is implemented by extraction, distillation, crystallization and/or desorption, this neprevyshenie propane and, if appropriate, propylene, usually recovered as a component of at least one other gas phase and in accordance with the proposed invention, the method preferably also return to the reaction zone And,

Recycling neprevyshenie prop is on and if necessary, propylene can be done, for example, in a mixture with the main residual gas, which in this description is called the total residual gas. Recycling can be realized also in the form returned to the reaction zone And the individual gas streams. Such recycling to the reaction zone And, obviously, can be realized also in the form of another gaseous source stream. Such individually return gas flows may not contain oxygen or may contain it (may be adverse residual gas (for example, if oxygen is generated as a result of steaming the air or blowing the head part of the distillation column of air that is used as a polymerization inhibitor).

As the primary and total residual gases and adverse residual gas in accordance with the present invention form containing neprevyshenie propane, molecular oxygen and, if necessary, neprevyshenie propylene residual gas is recycled into the reaction zone as a gaseous source stream 2. Formed in the separation zone In the remaining gas containing neprevyshenie propane and, if necessary, neprevyshenie propylene, but not containing molecular oxygen, according to the invention can be recycled to the reaction zone a mixture in the main residual gas and/or adverse residual gas (i.e., for example, as a component of overall residual gas), for example, as a component gaseous stream source 2 and/or also by yourself (in this case we are talking not about residual gas, which is returned to the reaction zone And in the context of the present invention). In the latter case, the recycling to the reaction zone And can be performed without any restrictions, i.e. for example also in the form of another gaseous source stream. First of all, if in accordance with the proposed invention method in the first separation zone And a partial flow 2 gas mixture of reaction products And will mostly all contained components that differ from propane and propylene, and the resulting flow of the gas mixture of the reaction products And' used for feeding at least one oxidation reactor, in accordance with the proposed invention a method in a reaction zone And return substantially all of the amount generated in the separation zone, containing neprevyshenie propane and, if necessary, neprevyshenie propylene gas flows through such recycling preferably in the form of a generic component of the residual gas that is used as a gaseous source stream 2. However, a partial amount (for example, as described in the emetsky the patent application DE-A 102004032129), if necessary, can also be used for other purposes, such as energy production and/or synthesis gas, and/or as a dilution gas in the reaction zone C. However, according to the invention in the above case, at least half or two-thirds (i.e. 50 or 66,6%), preferably, at least three quarters, even more preferably, the whole amount of the above-mentioned residual gas (corresponding to the individual main and/or side, respectively, of the total residual gas)generated in the separation zone, as a rule, return to the reaction zone And preferably as a component gaseous stream source 2. In the formation in the zone of separation In only one stream of residual gas containing neprevyshenie propane, molecular oxygen and neprevyshenie propylene (usually, often it is a similar situation), this thread according to the invention preferably completely (if necessary, minus partial amount of gas of the same composition, is introduced into the reaction zone as the dilution gas) returns as a gaseous source stream 2 into the reaction zone And, above all, if in accordance with the proposed invention method in the first separation zone And casting the thread 2 a mixture of products But are basically all the contained components, different from propane and propylene, and the resulting gas stream is a mixture of reaction products And' use then to supply, at least one oxidation reactor. However, this thread, as indicated above, can also be divided into two partial quantities of identical composition, and in the reaction zone as a gaseous source stream 2 can be recycled only one partial quantity, and the other partial number to use for other purposes. In the case of education in the separation zone In more than one of such residual gas stream, these streams according to the invention (as described above) can be recycled to the reaction zone together (for example, pre-combining). However, the recycling of these residual gas flows into the reaction zone And, obviously, you can also individually. A partial amount of residual gas can also return to the reaction zone And not as a gaseous source stream 2, but only along the reaction path heterogeneously catalyzed propane dehydrogenation in reaction zone A. In this case, the reaction by heterogeneously catalyzed dehydrogenation of propane in the first reaction zone And the mean path of the flow is contained in the flow of the reaction gas mixture And propane through the reaction zone And depending on otstapeno its transformation during dehydration (conversions by heterogeneously catalyzed dehydrogenation).

In accordance with the proposed invention by way of the residual gas is recycled into the reaction zone as a gaseous source stream 2 usually contains ≥70 vol.%, often ≥80% vol. and in most cases ≥90 vol.%, most often, ≥95 or ≥98% components, the boiling point of which at normal pressure (1 bar) is ≤-30°C.

First of all, if in accordance with the proposed invention method in the first separation zone And a partial flow 2 gas mixture of reaction products And will mostly all contained components that differ from propane and propylene, and the resulting flow of the gas mixture of the reaction products And' used for feeding at least one oxidation reactor, the gaseous source stream 2 has the following typical composition:

- from 0 to 2 vol.%, in most cases, from 0 to 1 vol.%, often from 0 to 0.5% vol. propylene,

- from 0 to 2 vol.%, in most cases, from 0 to 1 vol.%, often from 0 to 0.5% vol. acrolein,

from 0 to 0.5 vol.%, in most cases, from 0 to 0.1 vol.%, often from 0 to 0.05 vol.% acrylic acid,

- from 0 to 4 vol.%, in most cases, from 0 to 2 vol.%, often from 0 to 1.5%. COx,

from 10 to 50 vol.%, in most cases, from 20 to 30 vol.% propane,

from 0 to 70 vol.%, in most cases, from 40 to 70 vol.% nitrogen,

from 1 to 10 vol.%, in most cases the in from 2 to 5 vol.%, often from 2.5 to 3.5 vol.% oxygen and

- from 0 to 15 vol.% water.

The temperature of the gaseous stream source 2 in accordance with the proposed invention is a method often ranges from 50 to 200°C, respectively, from 70 to 130°C., and the pressure is in the range from 1.5 to 5 bar, preferably from 3 to 4 bar.

The typical temperature of the gaseous stream source 3 is from 0 to 50°C., frequently from 5 to 20°C and the pressure is in the range from 3 to 6 bar, respectively, from 4 to 5 bar.

In accordance with the proposed invention by way of a gaseous source stream 4 must be molecular hydrogen. Under molecular hydrogen in the present invention mean gas streams consisting of only one molecular hydrogen, or gas streams that contain at least 50 vol.%, preferably, at least 60 vol.%, at least 70 vol.%, at least 80 vol.%, at least 90 vol.%, at least 95 vol.%, at least 98 vol.% or at least 99 vol.% molecular hydrogen, and the balance to 100% vol. established appropriate amounts of inert gas. Under inert gas in this application in the General case, the mean component of the reaction gas, which in the conditions of the respective reactions (in the above case, in the conditions of the heterogeneously catalyzed dehydrogenation) is characterized by preimushestvenno inert behavior, and chemically unchanged for more than 95 mol.%, preferably more than 99 mol.% each of the components of an inert reaction gas. Examples of such inert gases are nitrogen, noble gases, carbon dioxide, and water vapor.

In accordance with the proposed invention is a method suitable the temperature of the gaseous stream source 4 is from 20 to 100°C., frequently from 40 to 60°C., and the pressure corresponds to the interval from 1 to 5 bar.

According to the invention is preferred method, according to which from 60 to 90 mol.%, preferably from 75 to 85 mol.% contained in the source of the reaction gas mixture And the molecular hydrogen formed partial stream 1 gas mixture of the reaction products (gaseous source stream 1)and the balance to 100 mol.%, comprising from 10 to 40 mol.%, respectively from 15 to 25 mol.%, formed gaseous source stream 4.

Other gaseous source flows used along with the gaseous source streams 1-4, notably water vapor, respectively finely dispersed droplets of the sprayed water. In a suitable embodiment, the temperature of such gas stream source 5, for example consisting of water vapor, is from 100 to 200°C., often from 120 to 160°C. and the pressure ranges from 1 bar to 4 bar.

In compliance and proposed in the invention by way of formed water vapor gaseous source stream 5 is introduced into the gaseous composition of the original mixed flow prior to the introduction of this mixed stream is a gaseous stream source 4.

Combining the above threads, it is advisable to implement the following way: first gaseous source stream 2 add gaseous source stream 5 and the resulting gaseous mixture of gaseous source stream 3.

Formed the original mixed gaseous stream is passed through indirect heat exchanger preferably only for the purpose of cooling the partial flow 2 gas mixture of the reaction products (for example, reducing the temperature of 500-600°C to 150-350°C) and simultaneous heat source gas flow (for example, raising its temperature from 20-200°C to 350-530°C). The presence of water vapor reduces the risk occurring during heating of coking. Then carry out the necessary according to the invention combining a gaseous source stream 4 is heated to above the temperature of the initial mixture flow, leading to the formation of flow of the gaseous mixture. According to the invention the temperature of the stream of gaseous mixture is preferably from 350 to 550°C and the pressure is in the range from 2 to 5 bar.

As reported in more detail below, the joint use of water vapor as gaseous source stream 5 primarily contributes to the prolongation of the lifetime of heterogeneous catalyst casticin the th dehydrogenation of propane. However, according to the invention from such sharing gaseous source stream 5 as possible, preferably refuse, preferably using contained in the gaseous source stream 2 water vapor, the presence of which in this thread is due to the formation of water at the stage of partial oxidation. According to the invention is suitable, the content of water vapor in the stream of the source of the reaction gas mixture a is from 1 to 20 vol.% or up to 15 vol.%, accordingly, up to 10 vol.%, often from 4 to 6 vol.%

First of all, if in accordance with a less preferred option proposed in the invention, a method for supplying at least one oxidation reactor using a partial flow 2 mixture of reaction products And, neprodvinuty processing in the first separation zone And, according to the invention should be distinguished from forming in the area of separation In the residual gas, at least a partial quantity soderjaschihsya it components that differ from propane, molecular oxygen and, optionally, propylene, before using this residual gas for the formation of a gaseous stream source 2.

The selection is described, for example, in European patent application EP-A 117146, application for U.S. patent US-A 3161670, as well as in non-is such patent applications DE-A 3313573, DE-A 10316039 and DE-A 10245585.

In accordance with the proposed invention method in the case of use in the reaction zone And loop technology optimal number of partial flow 1 mixture of reaction products And ranges from 25 to 75 vol.%, accordingly, from 30 to 70 vol.%, preferably from 40 to 60 vol.%, particularly preferably 50 vol.% in terms of the overall flow of the gas mixture of the reaction products A.

In accordance with the proposed invention by way of the degree of conversion of propane by passing the stream source of the reaction gas mixture a, which according to the invention is preferably formed only from a gaseous source streams 1, 2, 3 and 4, and, if necessary, used gaseous source stream 5, consisting of water vapor, may be from 20 to 30 mol.% (in terms of a single transmission stream source of the reaction gas mixture a through reaction zone a, as well As in terms of the total number of propane, that is, the total amount of fresh propane and propane contained in the gaseous source stream 2). However, in accordance with a particularly expedient embodiment of the proposed invention in the method above, the degree of conversion of propane ranges from 30 to 60 mol.%, preferably from 35 to 55 mol.% and particularly preferably from 35 to 45 mol.%.

The servant of the games, etc pressure at partial heterogeneously catalyzed propane dehydrogenation in reaction zone A, favorable for the implementation of the above degrees of its transformation, is from 0.3 to 10 bar, respectively, preferably up to 3 bar. The presence of water vapor can partially offset the impact of endothermy to dehydration, due to the high heat capacity of water; on the other hand, the dilution water vapor leads to a reduction in the partial pressure of the source and destination of products, which has a favorable effect on the equilibrium position of the reaction of dehydrogenation. Due to the dilution effect can be achieved also by sharing as other gaseous source flows other inert gases (e.g. nitrogen, carbon dioxide, and so forth). However, unlike these inert gases are water vapor, as noted above, has an additional beneficial effect on the service life used in the reaction zone And the catalyst.

Figure 3 shows two possible design options similar to the reaction zone A (dimensions in millimeters). Shown in the drawings the position of the mean:

1 - mixed workflow,

2 is a partial flow 2 gas mixture of reaction products And,

3 - stationary catalyst bed,

4 - nozzle jet pump,

5 - mixing pipe,

6 cone.

While RAS is od mixed workflow 1 may be, for example, 148 t/h, the temperature of 486°C and pressure 3,11 bar, respectively 3,51 bar. The corresponding flow partial flow 2 gas mixture of reaction products And is 148 t/h, and in a typical case, this stream may have a temperature of, for example, 600°C and a pressure of 2.3 bar. That is, the pressure of the suction jet pump can be 2.3 bar. This corresponds to the circulating flow total flow average of 296 t/h as the catalyst can be used, for example, rods with a diameter of 1.5 mm and a typical length of 3 to 7 mm according to example 4 of German patent application DE-A 10219879 (the total amount of catalyst is, for example, 30 tons). The bulk density of the stationary catalyst layer may be, for example, from 1200 kg/m3(loose packing) up to 1350 kg/m3(dense packing). The pressure immediately before the catalyst bed in the typical case would be 2,71 bar.

Below is a typical content of the main components of the source of the reaction gas mixture As:

propylenefrom >0 to 25 vol.%, in most cases from 1 to 10 vol.%, often from 2 to 7 vol.%,
acroleinfrom 0 to 1 vol.%, in most cases, from 0 to 0.5 vol.%, often the t 0 to 0.25%,
acrylic acidfrom 0 to 0.25%, in most cases, from 0 to 0.05 vol.%, often from 0 to 0.03%,
COxfrom 0 to 5 vol.%, in most cases, from 0 to 3 vol.%, often from 0 to 2 vol.%,
propanefrom 5 to 50 vol.%, preferably from 10 to 20 vol.%,
nitrogenfrom 30 to 80 vol.%, preferably from 50 to 70 vol.%,
oxygenfrom >0 to 5 vol.%, preferably from 1.0 to 2.0 vol.%,
water≥0 to 20 vol.%, preferably from 5.0 to 10.0 vol.%,
hydrogenfrom 0.5 to 10 vol.%, preferably from 1 to 5 vol.%

However, in General, as indicated above, the preferred and required is as low as possible a content of water vapor in the stream of the source of the reaction gas mixture A. To ensure satisfactory service life of the catalysts for the dehydrogenation stream source of the reaction gas mixture As the increase in the target degree of conversion of propane in the reaction zone And should contain larger quantities of water vapor.

In accordance with the proposed in which sobienie way an optimum molar ratio contained in the flow of the source of the reaction gas mixture And the molecular hydrogen contained in the molecular oxygen is about 2:1. The corresponding molar ratio contained in the flow of the source of the reaction gas mixture And the molecular hydrogen contained in the propane, as a rule, is ≤ 5:1. In accordance with the proposed invention by way molar ratio contained in the flow of the source of the reaction gas mixture And water vapor contained in it to propane in most cases is ≥ 0,05:1 to 2:1, respectively, to 1:1.

In accordance with the proposed invention by way of the reaction zone And preferably performed so that the molar ratio of propylene target to neprevyshenie the propane contained in the flow of the gas mixture of the reaction products And was 0.2:1, respectively, from 0.3:1 to 0.5:1 (if necessary, up to 0.66:1).

The reaction zone And may have insulated design, characterized by targeted heat flux source of the reaction gas mixture a noise outside fluid (i.e. liquid or gaseous) medium (in relation to a single deletion of the reaction stream through the reaction zone A). When a similar basis of comparison of the reaction zone And may have also adiabatic design, characterized by a predominant absence of the specified targeted taproom is on noise outside the carrier. In the latter case, due to the implementation of the recommended in the above prior art and described in the following technical measures thermal gross effect (in relation to single transmission of a stream of the source of the reaction gas mixture a through reaction zone A) can be endothermic (negative), autothermal (mostly zero) or exothermic (positive).

Heterogeneously catalyzed partial dehydrogenation of propane to propylene in typical cases requires the use of relatively high temperatures. Thus the conversion of propane is usually limited by thermodynamic equilibrium of the dehydrogenation reaction. Typical temperature dehydrogenation of propane ranges from 300 to 800°C, respectively, from 400 to 700°C. the Dehydrogenation of one mole of propane is accompanied by release of one mole of hydrogen.

The temperature of the dehydrogenation and removing formed as the reaction product of hydrogen and the reduction in the partial pressure due to the use of inert diluents provide a shift of thermodynamic equilibrium towards formation of the target product.

Partial heterogeneously catalyzed dehydrogenation of propane in the reaction zone And in principle can be achieved in (quasi)-o adiabatically and the endothermic effect. P and this thread is the source of the reaction gas mixture And with temperatures ranging from 450 to 700°C (respectively from 550 to 650°C) pass, at least one layer of catalyst. Adiabatic transmission source of the reaction gas mixture through the catalyst (can be used as fluidized and fixed bed of the catalyst, and according to the invention, it is preferable stationary catalyst bed) first, usually its the heat caused by the combustion of hydrogen, and then cooling to a temperature of approximately from 30 to 200°C depending on the degree of conversion of propane and dilution. Lowering the reaction temperature allows to prolong the service life used for its implementation catalyst. Increasing the reaction temperature increases the conversion of propane.

Technology heterogeneously catalyzed dehydrogenation of propane, it is expedient to make in the reaction zone And made in the form of shelving reactor.

In a suitable embodiment of such a reactor contains multiple consecutive layers of the dehydrogenation catalyst. The number of layers of catalyst may be from 1 to 20, suitable from 2 to 8, and from 3 to 6. Increasing the number of shelves allows to increase the degree of conversion of propane. The catalyst layers sequentially ordered preferably in radial or axial direction. Technologically tselesoobraznaya use in such shelf stationary reactor catalyst.

In the most simple embodiment, the stationary layers of catalyst are located in the shaft reactor axially or in the annular gap formed by the inserted one into the other cylindrical grate bars. It is also possible sequential arrangement of the annular gap in the form of segments and the transmission of gas in the radial direction from one segment to the one above it or below it the next segment.

In a suitable embodiment, at least the flow of the reaction gas mixture a shelf in the reactor from one catalyst layer to the next, it is subjected to intermediate heating, for example, by passing over the surfaces (e.g., ribs) heated by hot gases heat exchangers or through a heated hot combustible gases pipe (as the material it is advisable to use silicon steel grades, first of all, special steel, such as type no. 1.4841).

When operating shelving reactor in the adiabatic regime and the use of catalysts, primarily described in the German patent application DE-A 19937107, in particular, in embodiments, to achieve the above conditions, the degrees of conversion of propane constituting ≤30 mol.%, just enter pre-heated to a temperature of from 450 to 550°With the flow of the source of the reaction the gas mixture a shelf in the dehydrogenation reactor and stand inside it with appropriate limits temperature. This means that the total dehydrogenation of propane should be carried out at extremely low temperatures, which is especially beneficial effect on the service life of catalysts intended for the implementation of the dehydrogenation in the stationary layer. To achieve higher degrees of conversion of propane, it is expedient to introduce a shelf in the dehydrogenation reactor, the flow of the source of the reaction gas mixture And pre-heated to higher temperatures, which can reach 700°C, and to maintain him inside the reactor at respective specified limits of temperature.

In accordance with more complex technological option exercise described above intermediate direct heating of the stream source of the reaction gas mixture And (autothermal mode). In addition, the flow of the source gas mixture after the first catalyst layer (in the direction of transmission of the gas mixture), and the interval between subsequent layers usually add a small amount of molecular oxygen. This contributes, as a rule, kataliziruemom by dehydrogenation catalysts combustion limited number contained in the original reaction gas mixture of molecular hydrogen formed in the process for heterogeneously catalyzed propane dehydrogenation and/or added to the reaction is ionic gas mixture, moreover, if necessary, simultaneously burn small amounts of propane (can also be technologically feasible the use of an additional shelf in the reactor layers, which contain the catalyst, especially selectively catalyze the combustion of hydrogen (suitable catalysts of this type are known, for example, from U.S. patent US 4788371, US 4886928, US 5430209, US 5530171, US 5527979 and US 5563314, and containing such catalyst layers can be alternated shelf in the reactor, for example, with layers containing a dehydrogenation catalyst). According to the invention, it is preferable to use molecular hydrogen introduced only in the generated outside the reactor stream is the source of the reaction gas mixture A. the Heat of combustion of molecular hydrogen contributes to the implementation of quasiattractor heterogeneously catalyzed dehydrogenation of propane (gross heat effect is close to zero), occurring in almost isothermal process conditions. The long residence time of the reaction gas in the catalyst bed allows dehydrogenation of propane with declining or mostly constant temperature, which contributes to the prolongation of the service life of the catalysts for dehydrogenation.

The above oxygen supply in General should be done in about what atom, to its content in the reaction gas mixture in terms of present therein molecular hydrogen was varied from 0.5 to 50 vol.%, accordingly, up to 30 vol.%, preferably from 10 to 25 vol.% (specified quantitative ratio optimum for the content of the corresponding components in the stream is the source of the reaction gas mixture A). At the same time as the oxygen source can be used as pure molecular oxygen or oxygen diluted with an inert gas, such as carbon monoxide, carbon dioxide, nitrogen and/or noble gases, and, above all, the air as the oxygen source is preferably used exclusively air). Gaseous products of combustion, as a rule, provide for the effect of dilution of the reaction gases, and consequently, accelerate heterogeneously catalyzed dehydrogenation of propane. First of all, this applies to combustion water vapor.

The implementation of the heterogeneously catalyzed propane dehydrogenation in isothermal mode, optionally, to facilitate the introduction into the free space shelving reactor between catalyst contained built-in components (e.g. pipes), which before loading into the reactor is subjected to a preferred but optional vakuumirovaniya built-in items contain suitable solid materials or fluids, which at a certain temperature evaporate or melt, consuming the appropriate amount of heat, and in areas of reactor temperature, lower than point evaporation or melting, condensed, releasing heat.

Stream source of the reaction gas mixture And primarily used in the case specified autothermal process conditions, preferably has the following composition:

propanefrom 15 to 25 vol.%
propylenefrom 2 to 6 vol.%
water vaporfrom 5 to 20 vol.%
molecular hydrogenfrom 2 to 10 vol.%
molecular nitrogenfrom 40 to 75 vol.% and
molecular oxygenfrom >0 to 3%vol.

According to the invention a typical flow of the original reaction gas mixture And referred to the total amount loaded in the reactor catalyst dehydrogenation (the sum of all its layers), is from 250 to 5000 h-1(in the mode with the maximum load is also up to 40,000 h-1), preferably from 10000 to 25000 nl/l·h, about obinna preferably 15000 to 20000 nl/l·h The corresponding consumption in terms of propane in typical cases ranges from 50 to 1000 h-1(in the mode with the maximum load is also up to 40,000 h-1), preferably from 2000 to 5000 nl/l·h, particularly preferably from 3000 to 4000 nl/l·h

Proposed in the invention method allows for selectivity of the formation of propylene in the reaction zone And reaching 95 mol.% and more, even at high degrees of conversion of the original propane.

The output from the reaction zone (reactor dehydrogenation) partial flow 2 gas mixture of reaction products And reaction conditions selected for the implementation of the heterogeneously catalyzed dehydrogenation of propane, as a rule, is under a pressure of from 0.3 to 10 bar, preferably from 1 to 3 bar, and often has a temperature of from 450 to 650°C, respectively, up to 750°C, in most cases from 500 to 600°C. the Partial stream 2, as a rule, contains propane, propylene, hydrogen, nitrogen, water, methane, ethane (methane and ethane in most cases are formed due to thermal decomposition of a small amount of propane, ethylene, butene-1, other butylene, such as isobutylene, other4-hydrocarbons, such as n-butane, isobutane, butadiene, and so on, carbon monoxide, carbon dioxide, and, as a rule, the oxidation products such as alcohols, aldehydes and carboxylic sour is s (usually containing ≤9 carbon atoms). In addition, a partial stream 2 may contain minor amounts of components whose presence is due to the introduction into the reaction zone As a gaseous source stream 2.

In accordance with European patent application EP-A 117146, German patent application DE-A 3313573 and application for U.S. patent US-A 3161670 partial flow 2 gas mixture of reaction products And it is recommended to send directly, at least one oxidation reactor, while the present invention the preferred method is a preliminary selection from the specified stream, at least a partial quantity present in the components that differ from propane and propylene, only after which a partial flow 2 gas mixture of reaction products And direct on stage partial oxidation is contained in the propylene stream. It is necessary to consider the requirements formulated in the German patent application DE-A 10211275.

It should be noted that for the implementation proposed in the invention method heterogeneously catalyzed dehydrogenation of propane is in principle possible to use any known from the prior art dehydrogenation catalysts. Roughly they can be divided into two main groups. One of them form the oxide catalysts character (n is an example, the chromium oxide and/or aluminum oxide), while the other group includes catalysts comprising at least one, usually a relatively noble metal (e.g. platinum), caused, as a rule, on a carrier of an oxide type. Thus, you can use any of dehydrogenation catalysts, recommended, inter alia, in the international application WO 01/96270, European patent application EP-A 731077, German patent applications DE-A 10211275 and DE-A 10131297, international application WO 99/46039, application for U.S. patent US-A 4788371, European patent application EP-A-0705136, international application WO 99/29420, applications for U.S. patent US-A 4220091, USA US-A 5430220 and the United States US-A 5877369, European patent application EP-A-0117146, German patent applications DE-A 19937196, DE-A 19937105 and DE-19937107. Particularly suitable are catalysts of examples 1, 2, 3 and 4, described in the German patent application DE-A 19937107.

It is about the dehydrogenation catalysts which contain from 10 to 99.9 wt.% zirconium oxide, from 0 to 60 wt.% aluminum oxide, silicon dioxide and/or titanium dioxide and from 0.1 to 10 wt.%, at least one element of the first or second main group element of the third side of the group, the eighth element side group of the periodic system of the elements, lanthanum and/or tin, provided that the sum of these mass percent is 100.

Especially PR is good is also the catalyst for the dehydrogenation, used in the examples and comparative examples of the present invention.

In General, dehydrogenation use catalysts in the form of rods with a typical diameter of from 1 to 10 mm, preferably from 1.5 to 5 mm and a typical length of 1 to 20 mm, preferably from 3 to 10 mm, tablets, the size of which is preferably similar to the dimensions of the rods, and/or rings, typical outer diameter and length which are respectively from 2 to 30 or 10 mm, and suitable wall thickness from 1 to 10, 5 or 3 mm For the implementation of the heterogeneously catalyzed propane dehydrogenation in a fluidized bed (respectively fluidized bed or a moving layer) use appropriate catalysts, which have a higher dispersion. According to the invention in the reaction zone And preferably use a stationary catalyst bed.

The dehydrogenation catalysts (primarily used in the examples of the present invention, as recommended in the German patent application DE-A 19937107, primarily used in the respective examples) are usually prepared so that they were suitable for catalysis as propane dehydrogenation and combustion of molecular hydrogen. In the case of competition between the reaction of hydrogen combustion and the reactions of dehydrogenation and combustion of propane on p is such catalysts is much faster combustion of hydrogen.

For the implementation of the heterogeneously catalyzed propane dehydrogenation in principle any suitable known from the prior art reactors and technological options. Appropriate technological options are described, for example, all cited publications of the prior art relating to the dehydrogenation catalysts, and cited at the beginning of the present description of the prior art.

A relatively detailed description of the dehydrogenation suitable for implementing the present invention, is also provided in Catalytica®Studies Division, Oxidative Dehydrogenation and Alternative Dehydrogenation Processes, Study Number 4192 OD, 1993, 430 Ferguson Drive, Mountain View, California, 94043-5272 USA.

According to the invention before use partial flow 2 gas mixture of reaction products And as a source for propylene partial oxidation last proposed in the invention by way of this thread emit predominantly at least 50 vol.%, preferably, at least 75 vol.%, especially preferably at least 90 vol.% and even more preferably at least 95 vol.% different from propane and propylene components. For this purpose, in principle you can use any of the following in the German patent applications DE-A 102004032129, DE-A 102005013039, DE-A 102005009891, DE-A 102005010111, DE-A 102005009885, DE-A 102005028798 and DE-A 102455585 variants of the selection.

Suitable IU the od selection, satisfying the requirements of the present invention is, for example, in the implementation of the contact is preferably cooled (preferably to a temperature of from 10 to 100°C, respectively, to 70°C) partial flow 2 gas mixture of reaction products And with preferably a high boiling point, preferably a hydrophobic organic solvent, which is able to absorb from members of the partial stream 2 components mainly propane and propylene, and implement the specified contact under pressure, comprising, for example, from 0.1 to 50 bar, preferably from 5 to 15 bar, at a temperature of, component of, for example, from 0 to 100°C, preferably from 20 to 40°C., for example, a simple deletion of a partial flow 2 gas mixture of reaction products And through the above organic solvent. Due to subsequent desorption, rectification and/or Stripping with gas, which has an inert behavior in the subsequent partial oxidation of propylene and/or which is simultaneously used as a reagent necessary for the implementation of the subsequent partial oxidation of propylene (e.g., steaming through air or another mixture consisting of molecular oxygen and inert gas), can be regenerated propane and propylene in the form of a purified mixture, which can be used to partially the CSOs oxidation as a source of propylene (the above process is preferably carried out similarly to comparative example 1 of German patent application DE-A 102004032129). Generated during the implementation of the above absorption abgaz, optionally containing molecular hydrogen, may be subjected to separation, implemented, for example, adsorption at a variable pressure and/or membrane method (for example, according to the German patent application DE-A 10235419), and extracted from him the hydrogen can be used as a component stream of the source of the reaction gas mixture a (namely as a gaseous source stream 4).

However, the separation factor3-/C4-hydrocarbons when using the above technology are relatively low and often does not fit the in the German patent application DE-A 10245585 requirements.

In this regard, for solving problems of the present invention often preferred adsorption at alternating pressure or under pressure rectification as an alternative to the above separation by absorption.

To implement the above absorption separation as absorbents in principle any suitable absorbents capable of absorbing propane and propylene. Under the absorbent preferably imply preferably hydrophobic and/or high-boiling organic solvent. The boiling point of such solvent (at atmospheric pressure) advantages the government is at least 120°C, preferably at least 180°C., preferably from 200 to 350°C., especially from 250 to 300°C., more preferably from 260 to 290°C. the Optimum temperature of ignition of such a solvent at normal pressure equal to 1 bar) higher than 110°C. Suitable absorbents in General are non-polar organic solvents, such as aliphatic hydrocarbons, preferably nesadurai polar groups with external action, as well as aromatic hydrocarbons. In the General case, the adsorbent must have the highest possible boiling point and at the same time possibly higher ability to dissolve propane and propylene. Suitable absorbents are aliphatic hydrocarbons such as alkanes or alkenes with 6-20 carbon atoms, aromatic hydrocarbons, for example, a middle oil fraction distilling paraffins, ethers, is connected to the oxygen atom blocked (spatial dull) groups, or a mixture thereof, and these products can be added to a polar solvent, for example, similar to that used in the German patent application DE-A 43 08 087 1,2-dimethylphthalate. In addition, the absorbents suitable esters on the basis of benzoic acid and phthalic acid and unbranched alkanols with 1 to 8 carbon atoms, such as n-Buti the new ester benzoic acid, methyl ester benzoic acid, ethyl ester benzoic acid, dimethyl ester of phthalic acid, diethyl ester of phthalic acid, and the so-called heat transfer oils, such as diphenyl, diphenyl ether and mixtures of diphenyl with diphenyl ether or chlorinated derivatives and triarylamine, for example, 4-methyl-4'-benzylethanolamine and its isomers, such as 2-methyl-2'-benzyldimethylamine, 2-methyl-4'-benzylbiphenyl-methane and 4-methyl-2'-benzylethanolamine, as well as mixtures of these isomers. Suitable absorbent is a mixture of solvents preferably azeotropic composition consisting of diphenyl and diphenyl ether, which contains primarily about 25 wt.% of diphenyl (biphenyl) and about 75 wt.% diphenyl ether, for example, a commercially available product Diphyl®supplied, for example, the firm Voeg. Such solvent mixtures are often added from 0.1 to 25 wt.% solvent, such as dimethyl-phthalate (calculated on the total mixture of solvents). Particularly suitable absorbents are also octane, nonanes, decanes, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane and octadecane, and particularly suitable primarily are tetradecane. The optimum adsorbent has above boiling point, and at the same time not too high Molek is Arnau mass. The molecular weight of suitable absorbent is preferably ≤ 300 g/mol. Suitable absorbents are also described in the German patent application DE-A 3313573 paraffin oil with 8-16 carbon atoms. Examples of suitable commercially available absorbents are the products supplied by the company Haltermann, such as Halpasole i (for example, Halpasol 250/340 i and Halpasol 250/275 i), as well as oils for printing inks with the trade name PKWF and Printosol. Preferred absorbents are commercial products that do not contain aromatic compounds, for example, products of the type PKWFaf. In the presence of a small residual quantities of aromatic compounds their contents before using these products as absorbents can be reduced preferably by methods of distillation and/or adsorption to a value less than 1000 million-1massarini suitable trade products are n-paraffins from 13 to 17 carbon atoms, Mihagol®5 firm Erdöl-Raffinerie-Emsland GmbH, LINPAR®14-17 firm CONDEA Augusta S.p.A. (Italy), SASOL company Italy S.p.A. or high-boiling n-paraffins with 14-18 carbon atoms, manufactured by SLONAFT (Slovakia).

The typical contents of a linear hydrocarbon of the above products (based on the results of their analysis by gas chromatography according to the areas of the corresponding peaks) is:

with the MMA 9-C13- less than 1%, With14- from 30 to 40%, C15from 20 to 33%, C16from 18 to 26%, C17up to 18%, With≥18- less than 2%.

The product of the company SASOL has the following typical composition:

C13- 0,48%, C14of 39.8%, C15by 20.8%, C16- 18,9%, C17and 17.3%, C18-0,91%, C19to 0.21%.

The product of the company Haltermann has the following typical composition:

C13- 8%,C14- 4%, C1532.8 per cent; C16- 25,5%, C17- 6,8%,≥18- less than 0.2%.

When carrying out the absorption in the continuous mode, the composition of the adsorbent is subject to change accordingly.

Conditions for the exercise of absorption do not need any special restrictions. You can use any methods known in the art of absorption and conditions of its realization. Contact partial flow 2 gas mixture of reaction products And absorbent mainly carried out under pressure, comprising from 1 to 50 bar, preferably from 2 to 20 bar, more preferably from 5 to 15 bar, at a temperature of from 0 to 100°C., especially from 20 to 50°C, respectively, to 40°C. the Absorbance can be done in the respective columns, and in the apparatus with a sharp cooling gas flows. It can be in the mode of co-current, and (preferably) in the countercurrent mode. Suitable absorption columns are, for example, column trays (with colp what cikavymi and/or sieve plates), the column Packed with structured elements (e.g., supplementary sheet metal with a specific surface area of from 100 to 1000 m2/m3or up to 750 m2/m3for example, the nozzle Mellapak®250 Y) and Packed columns (for example, filled rings process). You can also use film columns with irrigated walls, spray columns, absorbers with graphite blocks, surface absorbers such as thick-film and thin-film absorbers, as well as disc scrubbers, horizontal scrubbers with mechanical stirring and rotary scrubbers. In addition, the optimal variant of implementation of the absorption involves the use of a bubble column with inline elements.

The selection of propane and propylene from the containing absorbent can be done by steaming, instant evaporation in an evaporation apparatus and/or by distillation.

The selection of propane and propylene from the containing absorbent is preferably carried out by steaming and/or desorption. Desorption can be implemented with conventional method, modifying the pressure and/or temperature, preferably at a pressure of from 0.1 to 10 bar, especially from 1 to 5 bar, more preferably from 1 to 3 bar and at a temperature of from 0 to 200°C, first is this from 20 to 100°C., more preferably from 30 to 70°C., particularly preferably from 30 to 50°C. is Used for steaming gas is, for example, water vapor, however, preferred are primarily mixtures of oxygen with nitrogen, for example, air. When using air, respectively, mixtures of oxygen with nitrogen, containing more than 10 vol.% oxygen, with the aim of narrowing the field of explosive combustion, it may be appropriate implemented before and/or during the process of steaming the addition of an appropriate gas. Particularly suitable are added gases are gases, specific heat which at 20°C is ≥29 j/mol·K, for example, such as methane, ethane, propane, propylene, benzene, methanol, ethanol, and ammonia, carbon dioxide and water. However, according to the invention preferably should be avoided as such additives4-hydrocarbons. Columns, especially suitable for the implementation of the steam, are also bubble column with inline elements.

The selection of propane and propylene from the containing adsorbent can be carried out by distillation, respectively, by distillation, using well-known specialists of the column, provided with a nozzle elements, the Packed bodies or relevant built-in elements. Preferred conditions for implementing the Oia distillation, accordingly rectification, involve the use of pressure which is from 0.01 to 5 bar, especially from 0.1 to 4 bar, more preferably from 1 to 3 bar, and temperature (in Cuba)constituting from 50 to 300°C., especially from 150 to 250°C.

The resulting steam absorbent stream source of propylene, in principle, suitable for feeding into the reaction zone In the proposed in the invention method, i.e. at the stage partial oxidation of propylene, the pre may be subjected to additional processing (for example, separation in kapitbisig and/or suction filters), the purpose of which is, for example, to reduce losses carry out this stream of absorbent and at the same time to prevent absorbent on stage implemented according to the invention the partial oxidation of propylene or further increase the efficiency of the separation of hydrocarbons From3/S4. The selection of the absorbent carried away by the stream source of propylene, can be performed by any known in the art methods. In accordance with the proposed invention a method is the preferred method of selection of absorbent material is, for example, rapid cooling (so-called hardening) gas flow of water, which implements the output stream of the Stripping device. The water absorbs the soda is jamica in the gas stream is absorbent and at the same time there is a saturation of the gas stream with water (a small amount of water stimulate the activity used in the present invention in the way of catalysts partial oxidation of propylene). Such leaching, respectively quenching gas flow can be realized, for example, countercurrent irrigation water in the head part of the desorption column, provided with a plate for trapping liquids, or the relevant single device.

To improve the efficiency of the allocation of the absorbent in the quenching space install built-in items, well-known experts in the field of distillation, absorption and desorption, which allows to increase the surface of the corresponding pin.

Water is preferably used to wash containing propane and propylene original thread due to the fact that usually it does not have a negative impact on subsequent partial oxidation of propylene. Generated in the process of washing the mixture with water absorbent material can be directed at the stage of phase separation, and subjected to washing the original thread directly to the step carried out according to the invention the partial oxidation of propylene.

In the preferred embodiment proposed in the invention method, you can get the source of the reaction gas mixture, which usually can be directly aimed at the partial oxidation, which primarily relates to the case of using air steam mixture p is cut with propane from absorbate. When not relevant to the invention the content of propane to the initial reaction of the gas mixture before using it to perform according to the invention the partial oxidation of the contained propylene, you can add an additional amount of fresh propane. In this case, the appropriate recycling propane on stage heterogeneously catalyzed dehydrogenation as a component stream of the source of the reaction gas mixture And carried out with residual gas (gaseous source stream 2). Thus it is possible to appropriately reduce fresh on propane dehydrogenation in the form of a gaseous source stream 3. In the extreme case, if fresh propane is completely added to the original reaction gas mixture fed to the partial oxidation of propylene, and as a component of the corresponding residual gas is directed into the flow of the reaction gas mixture a heterogeneously catalyzed dehydrogenation of propane only after the implementation phase partial oxidation of propylene, the need for fresh propane on stage heterogeneously catalyzed dehydrogenation can be completely excluded. Fresh propane, if necessary, can be added (for example, as odarivaemogo gas) in the allocation system With3-hydrocarbons, optionally located between node heterogeneously catalyzed dehydrogenation of propane and node partial oxidation of propylene.

In that case, if we are talking about the two-stage partial oxidation of propylene to acrylic acid, part or all of the amount of fresh propane can also be entered in the source of the reaction gas mixture used for exercising the second stage (however, this reaction gas mixture sometimes is not explosive in that case, if it is non-explosive mixtures is the source of the reaction gas mixture intended for the implementation of the first stage partial oxidation of propylene). Such preferred primarily due to the fact that avoids the occurrence of unwanted side reactions of propane in propionic aldehyde and/or propionic acid primarily on the first stage partial oxidation (propylene → acrolein). Preferred is also predominantly uniform distribution of fresh propane introduced into the first and second stage partial oxidation of propylene.

Thanks to the supply of fresh propane in the source of the reaction gas mixture phase partial oxidation of propylene can be targeted to generate specified the initial mixture in the explosion-proof version. For this purpose, if necessary, can also be recycled partial amount of residual gas directly to the stage partial is R propylene and/or acrolein. In addition, to ensure safety, if necessary, you can also use a mixture of fresh propane with residual gas. Crucial to answer the question, explosive or non-explosive should be considered as directed on stage partial oxidation of propylene source of the reaction gas mixture, is the fact that capable or not capable under certain initial conditions (under certain pressure and temperature) of the source of the reaction gas mixture to propagate combustion (fire, explosion), initiated by local ignition source (for example, a hot platinum wire) (see DIN 51649 and described in international application WO 04/007405 research). In accordance with the present invention, in the case of the spread of combustion of the mixture should be considered hazardous. In the absence of propagation of combustion in accordance with the present invention a mixture is considered non-explosive. In the absence of explosive source of the reaction gas mixture is non-explosive should be considered and the reaction gas mixture formed in the process proposed in the invention, the partial oxidation of propylene (see international application WO 04/007405).

However, in accordance with the proposed invention by way of fresh propane is generally imposed only in the flow of the outcome of the Oh reaction gas mixture A.

The present invention relates to manufacturing methods, in compliance with which is necessary for carrying out the invention method fresh propane (for example, a maximum of 75%, 50% or 25%) is injected into the stream source of the reaction gas mixture a, and at least a partial number (usually the rest of the number, if necessary, the entire quantity of fresh propane) being used for partial oxidation of propylene source of the reaction gas mixture, respectively, the source of the reaction gas mixture. For more information, see international application WO 01/96170, which should be considered an integral part of this application.

In accordance with known technology options partial heterogeneously catalyzed gas-phase oxidation of propylene to acrylic acid with molecular oxygen in principle carried out in two successive along the reaction coordinates of the stage, the first of which is the synthesis of acrolein, and the second stage consists in its transformation into acrylic acid.

Synthesis of acrylic acid in two successive time stages involves in itself known for the ability to stop the implementation proposed in the invention method, at the stage of obtaining acrolein (his primary education and to make the selection of the target product at this point, or continue the implementation proposed in the invention method, as long until the predominant formation of acrylic acid, and only then make the selection of the target product.

In the case of the implementation proposed in the invention method, with its end at the stage of primary education acrylic acid are preferred according to the invention is two-stage oxidation of propylene, and implementation of the process in two successive stages, and it is expedient in the best way to bring in mutual correspondence used at each of these stages stationary layers of catalyst, and preferably the other reaction conditions such as the temperature of the fixed catalyst layer.

Although multimetallic, especially suitable for use as the active mass of the catalyst of the first stage of oxidation (propylene → acrolein), containing elements such as molybdenum (Mo), iron (Fe) and bismuth (Bi), to a certain extent capable of catalyzing and the second stage of oxidation (acrolein → acrylic acid), to implement the second stage of oxidation are usually preferred catalysts, the active mass of which consists of at least one multimetallic containing molybdenum (Mo) and vanadium (V).

Thus, suitable to be implemented according to the invention a method of heterogeneous katal is projected partial oxidation of propylene on a stationary catalyst, active mass which is at least one containing molybdenum (Mo), iron (Fe) and bismuth (Bi) multimetallic, and first of all it is carried out in the form of a one-stage method of producing acrolein (and optionally acrylic acid) or in the form of the first reaction stage two-stage synthesis of acrylic acid.

This one-stage heterogeneously catalyzed partial oxidation of propylene to acrolein, and, if necessary, acrylic acid, respectively, two-stage heterogeneously catalyzed partial oxidation of propylene to acrylic acid, involving the use of formed according to the invention the source of the reaction gas mixture, can be carried out, in particular, in accordance with European patent application EP-A 700714 (the first stage of the synthesis, as proposed in this document and in the corresponding tubular reactor with countercurrent flow of the salt melt and the source of the reaction gas mixture), the European patent application EP-A 700893 (the second stage of the synthesis, as proposed in this document and in the corresponding countercurrent reactor), the international application WO 04/085369 (in the form of a two-stage synthesis, and description first of all, this application should be considered an integral part of the present description), the international application WO 04/85363, German for vcoi patent DE-A 10313212 (the first stage of synthesis), European patent applications EP-A 1159248 (in the form of a two-stage method), EP-A 1159246 (the second stage of the synthesis) and EP-A 1159247 (in the form of a two-stage method), the German patent applications DE-A 19948248 (in the form of a two-stage method) and DE-A 10101695 (in the form of a single-stage or two-stage method), the international application WO 04/085368 (in the form of a two-stage method), German patent application DE-A 102004021764 (in the form of a two-stage method), international applications WO 04/085362 (the first stage of synthesis), WO 04/085370 (second stage synthesis), WO 04/085365 (the second stage of the synthesis) and WO 04/085367 (in the form of a two-stage method), and in accordance with the European patent applications EP-A 990636, EP-A 1007007 and EP-A 1106598.

The above primarily relates to all embodiments of the present invention. They can all be implemented in accordance with these documents of the prior art, however, in contrast, the source of the reaction gas mixture for the first stage of the reaction (oxidation of propylene to acrolein is formed according to the present invention the source of the reaction gas mixture 2. The remaining parameters are analogous to those of examples of the implementation of the above cited inventions (first of all it concerns the stationary catalyst and flow noise through them reagent). In the case of the two-stage method, the oxide is Oia, providing a secondary flow of oxygen (secondary air) between the two stages of the reaction, the embodiments of the present invention perform the corresponding specific, except for the consumption of reagents, which is chosen so that the molar ratio of molecular oxygen to acrolein in the feed to the second stage of the mixture was similar to the one used in the examples of implementation of the cited inventions of the prior art. So, for example, used according to the present invention the source of the reaction gas mixture for the heterogeneously catalyzed partial gas-phase oxidation can be easily prepared by adding to the partial flow 2 gas mixture of reaction products And or flow of the gas mixture of the reaction products And' such a large number of molecular oxygen, which is necessary for the implementation of the partial oxidation. It is about applying as pure molecular oxygen and its mixture with an inert gas (or also only on the presence of inert gas). As such mixtures according to the invention preferably uses air. According to the invention, it is important to supply the specified oxygen so that the gas mixture of the reaction products remained In neprevyshenie molecular oxygen.

Molar Rel is the determination of molecular oxygen, contained in the source of the reaction gas mixture for the partial oxidation of propylene, containing this mixture, propylene, typically in the range of ≥ 1:1 to ≤ 3:1.

Multimetallic catalysts particularly suitable for the implementation stage partial oxidation of propylene, are described in detail and is well known to specialists. Examples of such catalysts described in European patent application EP-A 253409 (on page 5 of the corresponding U.S. patent).

Catalysts are well suited for implementation of the corresponding stage of oxidation, also known from German patent applications DE-A 4431957, DE-A 102004025445 and DE-A 4431949. First of all, it relates to catalysts of the General formula (I)given in both of the above earlier publications. Particularly preferred catalysts appropriate stage of the oxidation is described in the German patent applications DE-A 10325488, DE-A 10325487, DE-A 10353954, DE-A 10344149, DE-A 10351269, DE-A 10350812 and DE-A 10350822.

To carry out the proposed in the invention stage heterogeneously catalyzed gas-phase partial oxidation of propylene to acrolein, acrylic acid or their mixture, in principle, any suitable catalysts, the active mass which are containing molybdenum (Mo), bismuth (Bi) and iron (Fe) multimetallic.

First of all we are talking about multimetallic active masses about the soup of the formula (I) according to German patent applications DE-A 19955176 and DE-A 199 48 523, multimetallic active masses of the General formula (I), (II) and (III) according to German patent applications DE-A 10101695, DE-A 19948248 and DE-A 19955168, and multimetallic active masses, described in European patent application EP-A 7 00714.

In addition, suitable for implementation of the considered stage of oxidation multimetallic catalysts containing molybdenum, bismuth and iron, are given in revealing the essence of the invention paper No. 497012 from 29.08.2005, German patent applications DE-a 10046957, DE-A 10063162, DE-C 3338380, DE-A 19902562, European patent application EP-A 15565, German patent application DE-C 2380765, European patent applications EP-A 807465, EP-A 279374, German patent application DE-A 330 00 44, European application patent EP-A 575897, application for U.S. patent US-A 4438217, German patent application DE-A 19855913, international application WO 98/24746, German patent application DE-A 19746210 (multimetallic active mass General formula (II)), Japanese patent application JP-A 91/294239, European patent applications EP-A 293224 and EP-A 700714. First of all, it refers to examples of implementation of these inventions, especially preferred of which are shown in the descriptions of the European patent applications EP-A 15565, EP-A 575897 and German patent applications DE-A 19746210, DE-A 19855913. In this regard, special mention should be made of the catalyst described in European patent application EP-A 15565 of example 1 is, as well as the catalyst which can be prepared in accordance with this example, however, contains the active mass composition Mo12Ni6,5Zn2Fe2Bi1P0,0065K0,06Ox·10SiO2. In addition, special mention deserves the catalyst in the form of hollow cylinders with dimensions 5×3×2 mm (external diameter × height × internal diameter) of the in the German patent application DE-A 19855913 example 3, multimedallista mass which has a stoichiometric composition Mo12Co7Fe3Bifor 0.6K0,08Si1,6Oxand a solid catalyst based multimetallic General formula (II) from example 1 according to the German patent application DE-A 197 46 210. In addition, we should mention multimetallic catalysts described in application for U.S. patent US-A 4438217. Particularly suitable are hollow cylinders with dimensions of 5.5×3×3.5 mm, 5×2×2 mm, 5×3×2 mm, 6×3×3 mm, or 7×3×4 mm (outer diameter × height × internal diameter). Another possible form of such catalysts are the rods, for example, a length of 7.7 mm and a diameter of 7 mm and a length of 6.4 mm and a diameter of 5.7 mm

Many of the catalysts suitable for the implementation stage of the conversion of propylene to acrolein and, if necessary, acrylic acid, contain multimetallic active mass on the formula (IV):

in which

X1mean Nickel and/or cobalt,

X2means thallium, an alkali metal and/or alkaline earth metal,

X3mean zinc, phosphorus, arsenic, boron, antimony, tin, cerium, lead and/or tungsten,

X4means silicon, aluminum, titanium and/or zirconium,

a represents a number from 0.5 to 5,

b denotes a number from 0.01 to 5, preferably from 2 to 4

by means of a number from 0 to 10, preferably from 3 to 10,

d is a number from 0 to 2, preferably from 0.02 to 2,

E. means a number from 0 to 8, preferably from 0 to 5,

f denotes a number from 0 to 10, and

n means the number that is determined by the valency and frequency different from the oxygen elements in the General formula (IV).

These active multimetallic mass can be obtained by known methods (see, for example, German patent application DE-A 4023239), and usually they are used in the form of a molded mass of balls, rings or cylinders or in the form of layered catalysts, that is covered by the active mass of the inert bodies of the media. As catalysts, obviously, you can also use powdered active mass.

Active mass General formula (IV) can, in principle, be obtained by a simple method involving the preparation of suitable sources of the respective elements is ary components more thoroughly mixed, preferably finely dispersed dry mix the proper stoichiometric composition, which is subjected to calcination at a temperature of from 350 to 650°C. the Calcination can be performed in the atmosphere of inert gas and oxidizing atmosphere such as air (mixture of inert gas and oxygen), and also in reducing atmosphere (for example, in a mixture of inert gas, ammonia, carbon monoxide and/or hydrogen). The duration of calcination is from several minutes to several hours and can be reduced by increasing temperature. As sources of elemental components active multimetallic mass General formula (IV) can be used compounds which are already oxides and/or compounds that can be converted into oxides by heating in the presence of at least oxygen.

Similar to the original connections along with oxides can be primarily halides, nitrate, formate, oxalates, citrates, acetates, carbonates, complexes of amines, ammonium salts and/or hydroxides (thoroughly mixed dry mixture of these components optionally type compounds such as NH4OH, (NH4)2CO3, NH4NO3, NH4CHO2CH3COOH, NH4CH3CO2and/or ammonium oxalate, which sposobnykh subsequent dissociation and/or destruction, followed by the formation of gaseous volatile products and what is happening at the latest during the subsequent calcination of the mixture).

Thorough mixing can be subjected starting compound for the preparation of active multimetallic mass General formula (IV)under both dry and wet condition. In the case of dry mixing source compounds should be used in the form of fine powders and subjected to calcination after mixing and, if necessary, carry out the seals. However, preferred is a thorough mixing of the wet starting compounds. When mixed together the original connection, which usually represent the corresponding aqueous solutions and/or suspensions. Especially thoroughly mixed in this way dry mix get in if you come from sources of elementary components, which are exclusively in the dissolved state. The preferred solvent is water. Finally, the resulting water mass is subjected to drying is preferably carried out in a spray dryer at a temperature output component from 100 to 150°C.

Multimetallic active mass General formula (IV) can be used to implement the reactions is authorized stage propylene → acrolein (and if necessary, acrylic acid)" as in the powdered state, and obtained by molding the catalyst with certain geometrical parameters, and the molding can be performed before or after the final annealing operation. So, for example, compaction in powder form of the active mass or appropriate Naturhotel the annealing and/or subjected to partial annealing of the initial mass (e.g., pelletizing, extrusion or extrusion), it is possible to prepare solid catalyst required shape, and, if necessary, can be added AIDS such as graphite or stearic acid (as a means to improve slip and/or facilitate molding), and a reinforcing agent, such as microfibers of glass, asbestos, silicon carbide or potassium titanate. As recommended in the German patent application DE-A 102005037678, instead of the graphite used for formation as an aid, you can also add boron nitride with hexagonal lattice. Suitable geometric form of solid catalysts correspond, for example, solid or hollow cylinders having an external diameter and height of components from 2 to 10 mm Suitable wall thickness p is smaller cylinder is from 1 to 3 mm. Solid catalysts, obviously, may also have the form of balls, the diameter of which may range from 2 to 10 mm

Especially in the case of solid catalysts particularly favorable is the use of catalysts in the form of hollow cylinders with dimensions 5×3×2 mm (external diameter × length × internal diameter).

The molding powder of the active mass or corresponding powder not subjected to annealing and/or partially calcined initial mass, obviously, can be done also through its application to pre-formed inert carrier for catalysts. The application of active mass on the body of the carrier with the aim of obtaining a layered catalysts typically carried out in a suitable rotating the tank, for example, described in German patent application DE-A 2909671 or European patent applications EP-A 293859 and EP-A 714700. Applied to the body of the carrier powder weight it is advisable to moisturize and after applying again be subjected to drying, for example, hot air. Suitable thickness is deposited on the body of the carrier layer of the powder mass is from 10 to 1000 μm, preferably from 50 to 500 μm and particularly preferably from 150 to 250 microns.

At the same time as materials of media you can use a regular porous or nonporous aluminum oxide, dioxide is Rennie, the thorium dioxide, zirconium dioxide, silicon carbide or silicates such as magnesium silicate or aluminum silicate. In terms of the target response, implemented in accordance with the proposed invention method, these materials behave normally mostly inert. The pH of the media, you can make regular or irregular shape, and are preferred body media, which have a regular shape (e.g., the form of beads or hollow cylinder) and clearly pronounced surface roughness. Suitable is the use of having a rough surface, mainly non-porous spherical media of steatite, the diameter of which ranges from 1 to 10 mm, respectively, to 8 mm, preferably from 4 to 5 mm is Suitable is the use of the bodies of the media in the form of cylinders with a height from 2 to 10 mm and an external diameter of from 4 to 10 mm In the case of suitable according to the invention the pH of the medium in the form of rings, the thickness of their walls is usually from 1 to 4 mm, Subject to the preferred use according to the invention the annular body of the carrier have a height from 2 to 6 mm, an external diameter of from 4 to 8 mm and wall thickness from 1 to 2 mm According to the invention as a phone carrier primarily suitable ring size 7×3×4 mm (external diameter × length × internal is iameter). The dispersion applied to the surface of the bodies of the media catalytically active oxide masses, obviously, should be brought into conformity with the desired thickness of the resulting membrane (see European patent application EP-A 714700).

Multimetallic active masses, to be used on the stage of conversion of propylene to acrolein (and optionally acrylic acid), are also active mass General formula (V):

in which

Y1means bismuth or bismuth in combination with at least one of the following elements: tellurium, antimony, tin, copper,

Y2means molybdenum, tungsten or a combination of molybdenum and tungsten,

Y3means of alkali metal, thallium and/or samarium,

Y4mean alkaline earth metal, Nickel, cobalt, copper, manganese, zinc, tin, cadmium and/or mercury,

Y5means iron or iron in combination with at least one of the following elements: chromium and cerium,

Y6mean phosphorus, arsenic, boron and/or antimony,

Y7means rare earth metal, titanium, zirconium, niobium, tantalum, rhenium, ruthenium, rhodium, silver, gold, aluminum, gallium, indium, silicon, germanium, lead, thorium and/or uranium,

and' means a number from 0.01 to 8,

b' denotes a number from 0.1 to 30,

with' means the number is t 0 to 4

d' denotes a number from 0 to 20,

e' refers to the number of from > 0 to 20,

f' denotes a number from 0 to 6,

g' stands for a number from 0 to 15,

h' stands for a number from 8 to 16,

x', y' denote the numbers determined by the valency and frequency different from the oxygen elements in the General formula

(V)

and p

q do the numbers, for which (p:q) corresponds to the interval from 0.1:1 to 10:1,

moreover, the active mass General formula (V) contain a three-dimensional chemical composition Y1a'Y2b'Ox'that is different from the chemical composition of their local environment, and therefore these areas delimited from their local environment, and the maximum diameter of such areas (the longest line segment that passes through their center of gravity and connecting the two are on their surface (boundary surface) of a point is from 1 nm to 100 μm, frequently from 10 to 500 nm or from 1 to 50 μm, respectively, from 1 to 25 microns.

According to the invention particularly preferred multimetal oxide mass General formula (V) are those in which Y1means bismuth.

Preferred active masses of similar type (i.e. Y1meaning bismuth), in turn, are multimetallic mass General formula (VI):

in which

Z2 means molybdenum, tungsten or a combination of molybdenum and tungsten,

Z3mean Nickel and/or cobalt,

Z4means thallium, an alkali metal and/or alkaline earth metal,

Z5mean phosphorus, arsenic, boron, antimony, tin, cerium and/or lead,

Z6means silicon, aluminum, titanium and/or zirconium,

Z7means copper, silver and/or gold,

a” means a number from 0.1 to 1,

b” means a number from 0.2 to 2,

C” stands for a number from 3 to 10,

d” denotes a number from 0.02 to 2,

e” means a number from 0.01 to 5, preferably from 0.1 to 3,

f” means a number from 0 to 5,

g” means a number from 0 to 10,

h” means a number from 0 to 1,

x”, y” means the number determined by the valency and frequency different from the oxygen elements in the General formula (VI)

p”, q” means the ratio (p:q) corresponds to the interval from 0.1:1 to 5:1, preferably from 0.5:1 to 2:1, and even more preferred are multimetal oxide mass General formula (VI)in which Z2bmeans (W)band Z212means (Mo)12.

In addition, preferably, if suitable according to the invention multimetallic masses of the General formula (V) (respectively multimetallic masses of the General formula (VI), at least 25 mol.% (preferably, n is at least 50 mol.% and particularly preferably 100 mol.%) of the total number [Y1a'Y2b'Ox']p([BiaZ2bAboutx”]p) are present in the form of three-dimensional regions of the chemical composition of Y1a'Y2b'Ox'[BiaZ2bOx”], which differs from the chemical composition of their local environment, and therefore these areas delimited from their local environment, and the maximum diameter of such regions is from 1 nm to 100 μm.

Forming catalysts with multimetallic masses of General formula (V) perform similarly to the formation of catalysts with multimetallic masses of General formula (IV).

Preparation of active multimetallic mass General formula (V) are described, for example, in European patent application EP-A 575897, as well as in the German patent application DE-A 19855913.

Recommended above, inert carrier is also suitable in particular for use as inert materials, dilution and/or delimit the appropriate fixed catalyst layers, respectively, for the protection of stationary layers of catalyst and/or the formation of the bulk layer, intended for heating the gas mixture prior to its passage through the catalyst.

As stated in the above, as the active masses used in the second reaction stage (stage heterogeneously catalyzed gas-phase partial oxidation of acrolein in acrylic acid) in principle, any suitable containing molybdenum and vanadium multimetallic mass, for example, described in German patent application DE-A 10046928.

Many of suitable for implementation in this stage catalysts (for example, the catalysts described in the German patent application DE-A 19815281) contain multimetallic active mass General formula (VII):

,

in which

X1means tungsten, niobium, tantalum, chromium and/or cerium,

X2means copper, Nickel, cobalt, iron, manganese and/or zinc,

X3means antimony and/or bismuth,

X4means one or more alkali metals,

X5means one or more alkaline earth metals

X6means silicon, aluminum, titanium and/or zirconium,

a represents a number from 1 to 6,

b denotes a number from 0.2 to 4,

by means of a number from 0.5 to 18,

d is a number from 0 to 40,

E. means a number from 0 to 2,

f denotes a number from 0 to 4,

g denotes a number from 0 to 40 and

n means the number that is determined by the valency and frequency different from the oxygen elements in the General formula (VII).

Coz the ACLs to the invention are preferred active multimetallic mass General formula (VII), in which

X1means tungsten, niobium and/or chromium,

X2means copper, Nickel, cobalt and/or iron,

X3means antimony,

X4mean sodium and/or potassium,

X5mean calcium, strontium and/or barium,

X6means silicon, aluminum and/or titanium,

a represents a number from 1.5 to 5,

b denotes a number from 0.5 to 2,

by means of a number from 0.5 to 3,

d is a number from 0 to 2,

E. means a number from 0 to 0.2,

f denotes a number from 0 to 1, and

n means the number that is determined by the valency and frequency different from the oxygen elements in the General formula (VII).

According to the invention is even more preferred multimetal oxide mass General formula (VII), in turn, have the General formula (VIII):

,

in which

Y1means tungsten and/or niobium,

Y2mean copper and/or Nickel,

Y5mean calcium and/or strontium,

Y6means silicon and/or aluminum,

and' means a number from 2 to 4

b' denotes a number from 1 to 1.5,

with' means a number from 1 to 3,

f' denotes a number from 0 to 0.5,

g' stands for a number from 0 to 8 and

n' means the number that is determined by the valency and frequency different from the oxygen elements in the General formula (VIII).

Suitable according to the invention multimetallic the derivative of the active mass General formula (VII) can be prepared by the known methods for example, described in German patent application DE-A 4335973 or in European patent application EP-A 714700.

Suitable for the implementation of the reaction stage "acrolein → acrylic acid" multimetallic active mass, especially having the General formula (VII), in principle, can be obtained by a known method involving the preparation of suitable sources of the corresponding elementary components more thoroughly mixed, preferably fine dry mix the proper stoichiometric composition, which is subjected to calcination at a temperature of from 350 to 600°C. the Calcination can be performed in the atmosphere of inert gas and oxidizing atmosphere such as air (mixture of inert gas and oxygen), and also in reducing atmosphere (for example in the mixture of inert gas with reducing gases such as hydrogen, ammonia, carbon monoxide, methane and/or acrolein, or in themselves possessing a restorative effect gases). The duration of calcination is from several minutes to several hours and can be reduced by increasing the temperature of this process. Sources of elemental components multimetallic active masses of the General formula (VII) may be compounds which are already oxides and/or compounds which can be converted to oxides by heating in the presence of at least oxygen.

Thorough mixing can be subjected starting compound for the preparation of active multimetallic mass General formula (VII)under both dry and wet condition. In the case of dry mixing source compounds should be used in the form of fine powders and subjected to calcination after mixing and, if necessary, carry out the seals. However, preferred is a thorough mixing of the wet starting compounds.

When mixed together the original connection, which usually represent the corresponding aqueous solutions and/or suspensions. Especially thoroughly mixed in this way dry mix get in if you come from sources of elementary components, which are exclusively in the dissolved state. The preferred solvent is water. The resulting water mass is subjected to drying is preferably carried out in a spray dryer at a temperature output component from 100 to 150°C.

Cooked this way multimetallic active mass, primarily active mass General formula (VII), can be used for oxidation of acrolein as in the powdered state, and on ochomogo forming catalyst with certain geometrical parameters, moreover, the molding can be performed before or after the final annealing operation. For example, a seal located in a powdered state active mass or appropriate Naturhotel the annealing of the initial mass, implemented, for example, pelletizing, extrusion or extrusion, it is possible to prepare solid catalyst required shape, and, if necessary, can be added AIDS such as graphite or stearic acid (as a means to improve slip and/or facilitate molding), and a reinforcing agent, such as microfibers of glass, asbestos, silicon carbide or potassium titanate. Suitable geometric form of solid catalysts correspond, for example, solid or hollow cylinders having an external diameter and height of components from 2 to 10 mm Suitable wall thickness similar to the hollow cylinder is from 1 to 3 mm Solid catalysts, obviously, may also have the form of balls, the diameter of which may range from 2 to 10 mm (for example, 8,2 or 5.1 mm).

The molding powder of the active mass or corresponding powder, Naturhotel the annealing of the initial mass, obviously, can be done also through its application to a pre-molded inertnational for catalysts. The application of active mass on the body of the carrier with the aim of obtaining a layered catalysts typically carried out in a suitable rotating the tank, for example, described in German patent application DE-A 2909671 or European patent applications EP-A 293859 and EP-A 714700.

Applied to the body of the carrier powder weight it is advisable to moisturize and after applying again be subjected to drying, for example, hot air. Suitable thickness is deposited on the body of the carrier layer of the powder mass is from 10 to 1000 μm, preferably from 50 to 500 μm and particularly preferably from 150 to 250 microns.

At the same time as materials of media you can use a regular porous or nonporous aluminum oxide, silicon dioxide, thorium dioxide, zirconium dioxide, silicon carbide or silicates such as magnesium silicate or aluminum silicate. The pH of the media, you can make regular or irregular shape, and are preferred body media regular shape with a distinct surface roughness, for example, balls or hollow cylinders with a split bearing surface. Suitable is the use of mainly non-porous spherical bodies media from steatite with a rough surface whose diameter is from 1 to 10 mm, respectively, to 8 mm, preferably from 4 to 5 mm So what Braz, suitable spherical body media have a diameter of 8.2 mm or 5.1 mm Suitable is the use of the bodies of the media in the form of cylinders with a height from 2 to 10 mm and an external diameter of from 4 to 10 mm In the case of annular shape of the bodies of the media thickness of their walls is usually from 1 to 4 mm, to Be preferred to the use of the annular body of the carrier have a height from 2 to 6 mm, an external diameter of from 4 to 8 mm and wall thickness from 1 to 2 mm. as a phone carrier primarily suitable ring size 7×3×4 mm (external diameter × length × internal diameter). The dispersion applied to the surface of the bodies of the media catalytically active oxide masses, obviously, should be brought into conformity with the desired thickness of the resulting membrane (see European patent application EP-A 714700).

Multimetallic active masses, to be used on the stage of transformation of acrolein in acrylic acid, are also active mass General formula (IX):

,

in which

D means Mo12VaZ1bZ2c”Z3dZ4eZ5fZ6gOx",

E. means Z712CuhHi”Oy,

Z1means tungsten, niobium, tantalum, chromium and/who do cerium,

Z2means copper, Nickel, cobalt, iron, manganese and/or zinc,

Z3means antimony and/or bismuth,

Z4means lithium, sodium, potassium, rubidium, cesium and/or hydrogen

Z5means magnesium, calcium, strontium and/or barium,

Z6means silicon, aluminum, titanium and/or zirconium,

Z7means molybdenum, tungsten, vanadium, niobium and/or tantalum, preferably molybdenum and/or tungsten,

a” means a number from 1 to 8

b” means a number from 0.2 to 5,

with” means a number from 0 to 23

d” denotes a number from 0 to 50,

e” means a number from 0 to 2,

f” means a number from 0 to 5,

g” means a number from 0 to 50,

h” means a number from 4 to 30,

i” denotes a number from 0 to 20,

x”, y” means the number determined by the valency and frequency different from the oxygen elements in the General formula IX, and

p, q mean different from zero in the number, for which (p:q) corresponds to the interval from 160:1 to 1:1,

moreover, these active mass can be obtained from a separate pre-formation present in the powdered state solid multiliteracies mass (initial mass 1)

which then with the necessary quantitative relation p to q is introduced into an aqueous solution, aqueous suspension or fine dry stagione the historical mixture of D sources of molybdenum, vanadium, elements of the Z1, Z2, Z3, Z4, Z5, Z6(initial mass 2)

if necessary, the resultant aqueous mixture is subjected to drying, and dry prior mass before or after drying, calcined at a temperature of from 250 to 600°C., obtaining a catalyst of the desired geometric shape.

Preferred are multimetallic mass General formula (IX), which receive, through the introduction of pre-formed solid source mass 1 in the water source mass 2 at a temperature below 70°C. the Preparation of catalysts based on multimetallic active masses of the General formula (IX) is described, for example, in European patent application EP-A 668104 and German patent applications DE-A 19736105, DE-A 10046928, DE-A 19740493 and DE-A 19528646.

Catalysts with multimetallic masses of General formula (IX) is formed similarly to the formation of catalysts with multimetallic masses of General formula (VII).

In the reaction stage of the conversion of propylene to acrolein is preferable to use a solid ring-shaped catalysts, while at the stage of transformation of acrolein in acrylic acid is preferably used layered catalysts in the form of rings.

Partial oxidation of propylene to acrolein (and optionally acrylic acid) in the accordance with the proposed invention by way involving the use of the above catalysts can be carried out, for example, contains a large number of contact tubes tubular alarm reactor with a fixed bed of catalyst, described in the German patent application DE-A 4431957. While the reaction gas mixture and the heat transfer medium (medium heat) can pass through the reactor with co-current or counter-current.

The pressure of the reaction is usually in the range of 1 to 3 bar and the total consumption (source) of the reaction gas mixture 2, passed through a stationary catalyst bed is preferably from 1500 to 4000 nl/l·h, respectively, up to 6000 nl/l·h or higher. Typical consumption of propylene through a stationary catalyst bed is from 90 to 200 nl/l·h, respectively, up to 300 nl/l·h or higher. According to the invention particularly preferred propylene consumption is more than 135 nl/l·h, respectively ≥140, ≥150 or ≥160 nl/l·h, because the presence of neprevyshenie propane used according to the invention the source of the reaction gas mixture makes its optimal behavior in a hot spot.

The source of the reaction gas mixture is introduced into one zone of the tubular reactor with a fixed bed of catalyst, preferably from above. The coolant, it is advisable to use molten salt, preference is sustained fashion consisting of 60 wt.% potassium nitrate (KPO 3) and 40 wt.% sodium nitrite (NaNO2or out of 53 wt.% potassium nitrate (KPO3), 40 wt.% sodium nitrite (NaNO2) and 7 wt.% sodium nitrate (NaNO3).

As stated above, it is possible to pass the salt melt and reaction gas mixture through the reactor as a co-current and countercurrent (if you look at the reactor top). Molten salt washes contact tube is preferably in the form of a meandering stream.

By passing the reaction gas mixture through the contact tube in the downward direction filling the catalyst (in the upward direction), it is advisable to implement the following way (by passing the reaction gas mixture in the upward direction it is feasible to reverse the sequence of the fill-tube reactor with catalyst):

- the lower parts of the contact tubes (from 40 to 80%, respectively, up to 60% of their total length) fill only one catalyst or its mixture with an inert material, the content of which in the mixture given up to 30 wt.%, accordingly, up to 20 wt.% (a section of the reactor),

subsequently, the areas of contact tubes (from 20 to 50%, respectively, up to 40% of their total length) fill only one catalyst or its mixture with an inert material, the content of which in the respective mixtures of up to 40 wt.% (the section of the reactor), and

top sites contact tubes (10 to 20% of their total length) filled with inert material, the download of which is preferably carried out in such a way as to ensure minimum loss of pressure (section a reactor).

In a section that is preferably loaded undiluted inert catalyst.

The above option should be used if the reactor is filled with catalyst specified in the description of the invention No. 497012 from 29.08.2005, example 1, is shown in the German patent application DE-A 10046957, or in example 3, described in the German patent application DE-A 10046957, and as the inert material used rings made of steatite with dimensions of 7×7×4 mm (external diameter × height × internal diameter). The temperature of the salt melt is similar to the temperature specified in the German patent application DE-A 4431957.

Implemented according to the invention the partial oxidation of propylene to acrolein (and, if necessary, acrylic acid), providing for the use of the above catalysts can be made, for example, described in German patent applications DE-A 19910506, DE-A 102005009885, DE-A 102004032 129, DE-A 102005013039, DE-A 102005009891, and also DE-A 102005010111 dual-zone tubular reactor with a fixed bed of catalyst. In accordance with these proposals (as well as in the General case, in accordance with the proposed in the present invention by the way) conversion about Elena in a single passage through the reactor is typically ≥90 mol.%, accordingly ≥95 mol.% when the selectivity of the formation of acrolein, component ≥90 mol.%. According to the invention the partial oxidation of propylene to acrolein, acrylic acid, or their mixtures are preferably carried out similarly, European patent application EP-A 1159244 and even more preferably similarly, international applications WO 04/085363 and WO 04/085362.

Description European patent application EP-A 1159244 and international applications WO 04/085363 and WO 04/085362 should be considered an integral part of this description.

Thus, exercisable in accordance with the present invention, partial oxidation of propylene is particularly preferably possible to carry out his transmission with a high flow rate through a stationary catalyst bed comprising at least two temperature zones.

In this regard, reference should be made, for example, in European patent application EP-A 1159244 and international application WO 04/085362.

In accordance with the proposed invention by way of the source of the reaction gas mixture used for the partial oxidation of propylene to acrolein, may have the following typical composition:

propylenefrom 5 to 9%vol.
molecular oxygenfrom 8 to about 18.
propanefrom 6 to 30 vol.% (respectively up to 35 vol.%)
molecular nitrogenfrom 32 to Ob.%.

In the case of the two-stage partial oxidation of propylene second reaction stage, namely the partial oxidation of acrolein in the acrylic acid can be carried out using the above catalysts, for example, in one zone of the tubular reactor with a fixed bed of catalyst, such as described in German patent application DE-A 4431949. While the reaction gas mixture and the coolant can pass through the reactor with cocurrent flows in the downward direction. In the second stage (stage partial oxidation of acrolein) usually refer obtained according to the invention the mixture of products of the previous stage partial oxidation of propylene to acrolein without adverse selection components (after, if necessary, completed intermediate cooling, which can be indirect or direct, for example, through the supply of secondary air).

Molecular oxygen is required for the implementation of the second reaction stage (partial oxidation acrolein), may already be present in the source of the reaction gas mixture is directed to the step carried out according to the invention partly what about the oxidation of propylene to acrolein. However, it can also partially or fully to enter into a mixture of products of the first reaction stage (i.e. stage partial oxidation of propylene to acrolein) is preferably in the form of (secondary) air, and also in the form of pure oxygen or mixtures of oxygen with inert gas. Regardless of the source of the reaction gas mixture is directed to the stage partial oxidation of acrolein in acrylic acid, preferably has the following composition:

acroleinfrom 4 to 8 vol.%
molecular oxygenfrom 2.25, respectively 4,5%vol., up to 9%vol.
propanefrom 6 to 30 vol.%
molecular nitrogenfrom 32 to 72%vol.
water vaporfrom 5 to 15 vol.%

Above the source of the reaction gas mixture preferably has the following composition:

acroleinfrom 5 to 8 vol.%
molecular oxygenfrom 2,75, respectively 5,5%vol., up to 9%vol.
propanefrom 10 to 25 vol.%
molecular nitrogenfrom 40 to 70 vol.%
water vaporfrom 5 to 15 vol.%

Above the source of the reaction gas mixture is more preferably has the following composition:

acroleinfrom 5 to 8 vol.%, preferably from 6 to 7 vol.%
molecular oxygen3, respectively 6%vol., up to 9%vol.
propanefrom 10 to 20 vol.%, preferably from 10 to 16%vol.
molecular nitrogenfrom 50 to 65% by and
water vaporfrom 7 to 13%vol.

preferably the intervals implemented independently from each other, but preferably at the same time.

In the implementation as the first (propylene → acrolein)and second (acrolein → acrylic acid) reaction stages, the pressure is usually in the range of 1 to 3 bar and the total consumption (source) of the reaction gas mixture is passed through a stationary catalyst bed is preferably from 1500 to 000 nl/l·h, accordingly, up to 6000 nl/l·h or more. The typical expense of acrolein passed through a stationary catalyst bed is from 90 to 190 nl/l·h or up to 290 nl/l·h or more. Consumption of acrolein particularly preferably amounts to more than 135 nl/l·h, respectively ≥140, ≥150 or ≥160 nl/l·h, because the presence of propane used according to the invention the source of the reaction gas mixture also makes its optimal behavior in a hot spot.

In a suitable embodiment, the degree of transformation of acrolein in terms of a single pass of the reaction gas mixture through the fixed catalyst bed is typically ≥90 mol.% with appropriate selectivity education acrylic acid component ≥90 mol.%.

The source of the reaction gas mixture is also introduced into one zone of the tubular reactor with a fixed bed of catalyst, preferably from above. As the coolant in a suitable embodiment, the second reaction stage is also used salt melt, preferably consisting of 60 wt.% potassium nitrate (KPO3) and 40 wt.% sodium nitrite (NaNO2or out of 53 wt.% potassium nitrate (KNO3), 40 wt.% sodium nitrite (NaNO2) and 7 wt.% sodium nitrate (NN3). As stated above, it is possible to pass the salt melt and reaction gas mixture through the reactor as pramot the com, and a counter (if you look at the reactor top). Molten salt washes contact tube is preferably in the form of a meandering stream.

By passing the reaction gas mixture through the contact tube in the downward direction filling the catalyst (in the upward direction) should be carried out as follows:

- the lower parts of the contact tubes (from 50%to 80%, respectively, up to 70% of their total length) fill only one catalyst or its mixture with an inert material, the content of which in the mixture given up to 30 wt.%, accordingly, up to 20 wt.% (a section of the reactor),

subsequently, the sections of the contact tube (20 to 40%, respectively, up to 40% of their total length) fill only one catalyst or its mixture with an inert material, the content of which in the respective mixtures of up to 40 wt.%(the section of the reactor), and

- the upper parts of the contact tubes (5 to 20% of their total length) filled with inert material, the loading of which is preferably carried out in such a way as to ensure minimum loss of pressure (section a reactor).

In the section download the catalyst, preferably diluted with an inert material. Like implemented in the General case of a heterogeneously catalyzed gas-phase partial oxidation of acrolein in acrylic is islote (especially at high flow acrolein through the layer of catalyst and high content of water vapor in the source gas mixture) can also consist of two consecutive layers diluted catalyst (to ensure a minimum temperature in the hot spot and its sensitivity). In the lower part of the section To load the catalyst containing up to 30 wt.% (respectively up to 20 wt.%) inert material, and in its upper part, a catalyst containing from >20 to 50 wt.%, accordingly, up to 40 wt.% inert material. In this case, the section With preferably contains undiluted inert catalyst.

In the case of a transmission source of the gas mixture through a contact tube in the upward direction it is feasible to reverse the sequence of filling the catalyst.

The above option is useful especially in the case of catalysts, such as those shown in example of manufacture 5 of German patent application DE-A 10046928 or examples from German patent application DE-A 19815281, and inert materials in the form of rings made of steatite with dimensions of 7×7×4 mm or 7×7×3 mm (external diameter × height × internal diameter). The temperature of the salt melt is similar to the one mentioned in the German patent application DE-A 4431949. The temperature is typically chosen so that at a single transmission of acrolein through its conversion reactor in the usual case was ≥90 mol.%, accordingly ≥95 mol.% or ≥99 mol.%.

Partial oxidation of acrolein in the acrylic acid used is Lovanium the above catalysts can be made, for example, dual-zone tubular reactor with a fixed bed, such as those described in the German patent application DE-A 19910508. The degree of conversion of acrolein similar to the one mentioned above. As in the partial oxidation of acrolein implemented as discussed above second reaction stage two-stage oxidation of propylene to acrylic acid in a two-zone tubular reactor with a fixed bed of catalyst, to generate the initial reaction of the gas mixture, it is advisable to directly use the gas mixture of the reaction products of the first stage partial oxidation if necessary after its indirect and direct (for example, through the supply of secondary air) intercooler. Required for partial oxidation of acrolein oxygen is used preferably in the form of air (if necessary, also in the form of pure molecular oxygen or a mixture of molecular oxygen with an inert gas, adding, for example, directly to the mixture of the products of the first stage of two-stage partial oxidation (propylene → acrolein). However, as indicated above, the molecular oxygen can be present already in the original reaction gas mixture intended for the first reaction stage.

When the two-stage partial oxidation of propylene to acrylic acid with C the direct use of the product gas mixture of the first stage partial oxidation for filing in the second stage of partial oxidation consistently connect, typically, two single-band tubular reactor with a fixed catalyst (as in the General case, at high flow of reactants through the catalyst, it is preferable to bypass the reaction gas and molten salt (brine) through the tubular reactor) or two two-zone tubular reactor with a fixed catalyst. It is also possible mixed serial connection reactors (single-band/dual-zone or Vice versa).

Between the reactors may be located intermediate the fridge, which optionally may contain a filter layer of inert material. The temperature of the salt melt in tubular reactors used to implement the first stage of two-stage partial oxidation of propylene to acrylic acid generally ranges from 300 to 400°C. the temperature of the molten salt in a tubular reactor of the second stage partial oxidation of propylene to acrylic acid (stage partial oxidation of acrolein in acrylic acid) in most cases ranges from 200 to 350°C. in Addition, the flow of fluids (preferably molten salt), passed through the corresponding tubular reactors with a stationary catalyst, usually chosen so that the difference of the temperatures at the inlet and outlet was generally ≤5°C. the Ka is indicated above, the two-stage partial oxidation of propylene to acrylic acid can be carried out in one reactor on a single loaded catalyst similar to that described in the German patent application DE-A 10121592.

It should also be recalled that the portion allocated to the first stage of the synthesis (propylene → acrolein") the source of the reaction gas mixture may be residual gas partial oxidation.

As noted above, under such residual mean gas containing molecular oxygen gas remaining after separation of the target product (acrolein and/or acrylic acid from product gas mixture of the partial oxidation, part of which can be recycled as inert dilution gas to the first and/or optionally the second stage partial oxidation of propylene to acrolein and/or acrylic acid.

However, according to the invention is similar to the residual gas containing propane, molecular oxygen and, if necessary, neprevyshenie propylene, preferably to recycle carried out in the reaction zone And heterogeneously catalyzed dehydrogenation of propane is preferably only as a gaseous source stream 2.

Thus, the tubular reactor with a catalyst, which upon completion of the first reaction stage corresponding the way altered along individual contact tubes, is the simplest form of implementation of both stages of the two-stage partial oxidation of propylene to acrylic acid (such as implemented in a single reactor two-stage partial oxidation of propylene is described, for example, in European patent applications EP-A 911313, EP-A 979813 and EP-A 990636 and German patent application DE-A 2830765). When this is loaded into the contact tube, the catalyst optionally contains an intermediate layer of inert material.

However, the two stage oxidation is preferably carried out in two series-connected tubular systems. Such tubular system may be located within a single reactor, and the transition from one tube bundle to another formed outside the contact tubes with an inert material, preferably available for passing the reaction gas. The coolant usually washes the contact tube, but not in contact with the outside contact of the tubes with an inert material. In this regard, in the preferred embodiment, both of the beam contact tubes are placed in the appropriate spatial separated reactors. Between the two tubular reactors is generally located intermediate the refrigerator that is designed to minimize what is happening in some cases, the secondary oxidation of crole is on, which is contained in the output from the first oxidation zone of the gas mixture of the reaction products. The temperature of the first reaction stage (propylene → acrolein) typically ranges from 300 to 450°C., preferably from 320 to 390°C. the Temperature of the second reaction stage (acrolein → acrylic acid) typically ranges from 200 to 370°C., often from 220 to 330°C. the Pressure in both zones of oxidation in a suitable embodiment, ranges from 0.5 to 5 bar, preferably from 1 to 3 bar. The flow passed through the catalysts of the oxidation reaction gas for both reaction stages is often ranges from 1500 to 2500 nl/l·h, respectively 4000 nl/l·h, and the consumption of propylene can be from 100 to 200 nl/l·h or 300 nl/l·h

The design of the two-stage oxidation according to the proposed invention the method can in principle correspond to the variant described, for example, in German patent applications DE-A 19837517, DE-A 19910506, DE-A 19910508 and DE-A 19837519.

While an excess of molecular oxygen relative to the required stoichiometric amount is a positive effect on the kinetics of the reactions realized at both stages of gas-phase partial oxidation, as well as on the service life of the respective catalysts.

Heterogeneously catalyzed gas-phase partial oxidation of propylene to acrylic acid under implementation in the accordance with the present invention, in principle can also be accomplished in only one zone of the tubular reactor as follows. Both reaction stages is realized in one oxidation reactor, loaded with one or more catalysts containing molybdenum, iron and bismuth multiliteracies active mass, able to catalyze both reactions. Possible, obviously, is also continuous or abrupt modification of the loaded catalyst along the reaction coordinates. When implemented according to the invention the two-stage partial oxidation of propylene to acrylic acid, structurally designed in the form of two successive stages of oxidation of the gas mixture of the products of the first stage of oxidation, if necessary, obviously, can also be partially or completely isolate the contained carbon monoxide and water vapor, which are formed at this stage as by-products before submitting formed in the first stage, the gas mixture in the second stage of oxidation. According to the present invention preferably choose a technology that does not require such a selection.

As indicated above, the source of molecular oxygen is added between the two stages of oxidation, along with (preferably) used air can serve as pure molecular oxygen and the molecular the initial oxygen diluted with an inert gas, such as carbon dioxide, carbon monoxide, noble gases, nitrogen and/or saturated hydrocarbons.

In accordance with the proposed invention the method can be carried out also direct cooling of the gas mixture of the reaction products formed in the first stage partial oxidation, by adding to them, for example, cold air, which is used as a component of the source of the reaction gas mixture intended for the second stage of partial oxidation.

According to the present invention, the partial oxidation of acrolein in acrylic acid is preferably carried out in accordance with European patent application EP-A 1159246 and even more preferably in accordance with international applications WO 04/085365 and WO 04/085370. However, according to the invention as containing acrolein source of the reaction gas mixture is preferably a mixture of products formed in the first stage of the proposed invention in partial oxidation of propylene to acrolein, which, if necessary, add this amount of secondary air to the ratio of molecular oxygen to acrolein in the received source of the reaction gas mixture in all cases was in the range of from 0.5:1 to 1.5:1. Description European patent application EP-A 1159246, the international applications WO 04/08536 and WO 04/085370 should be considered an integral part of this description.

Thus, the partial oxidation of acrolein in acrylic acid according to the present invention preferably can be performed in a stationary catalyst bed at elevated flow noise through acrolein, and the catalyst includes at least two temperature zones.

The two-stage partial oxidation of propylene to acrylic acid is preferably carried out in accordance with European patent application EP-A 1159248, respectively the international application WO 04/085367 or WO 04/085369.

The flow of gaseous mixture of the reaction products after made according to the invention, partial oxidation (corresponding to the first and/or second reaction stages) in the case of the synthesis of acrolein and/or acrylic acid typically consists mainly of acrolein, acrylic acid or mixtures of acrylic acid with acrolein as target products, neprevyshenie of molecular oxygen (for extension of the service life of the used catalysts favorably to the oxygen content remaining in the product gas mixture of the two stages of partial oxidation, was at least 1.5 to 4 vol.%), propane, neprevyshenie propylene, molecular nitrogen, which is formed as a by-product and/or used as a dilution gas water is Ara, formed as by-products and/or used as dilution gases oxides of carbon, small amounts of low molecular weight aldehydes, low molecular weight aliphatic carboxylic acids (e.g. acetic acid, formic acid and propionic acid), maleic anhydride, benzaldehyde, aromatic carboxylic acids and anhydrides of aromatic carboxylic acids (e.g. phthalic anhydride and benzoic acid), optionally, other hydrocarbons, such as C4-hydrocarbons (e.g., butene-1 and other isomers of butene), and other inert dilution gas.

The target products can be isolated from the gas mixture of the reaction products In the second separation zone In the well-known methods (for example, partial or complete, and, if necessary, fractionation condensation of acrylic acid, the absorption of acrylic acid in water or high-boiling hydrophobic organic solvent or absorption acrolein water or aqueous solutions of low molecular weight carboxylic acids, as well as subsequent processing of condensates and/or absorbates; according to the invention, it is preferable fractionation condensation of the gas mixture of reaction products; see, for example, European patent application EP-A 1388533, EP-A 1388532, German Savona patent DE-A 10235847, European patent application EP-A 792867, international application WO 98/01415, European patent application EP-A 1015411, EP-A 1015410, international application WO 99/50219, WO 00/53560, WO 02/09839, German patent application DE-A 10235847, international application WO 03/041833, German patent application DE-A 10223058, DE-A 10243625, DE-A 10336386, European patent application EP-A 854129, application for U.S. patent US-A 4317926, German patent application DE-A 19837520, DE-A 19606877, DE-A 190501325, DE-A 10247240, DE-A 19740253, European patent application EP-A 695736, EP-A 982287, EP-A 1041062, EP-A 117146 and German patent application DE-A 4308087, DE-A 4335172, DE-A 4436243, DE-A 19924532, DE-A 10332758, DE-A 19924533). Selection of acrylic acid can be carried out in accordance with European patent applications EP-A 982287, EP-A 982289, German patent applications DE-A 10336386, DE-A 10115277, DE-A 19606877, DE-A 19740252, DE-A 19627847, European patent applications EP-A 920408, EP-A 1068174, EP-A 1066239, EP-A 1066240, international applications WO 00/53560, WO 00/53561, German patent application DE-A 100 53 086 and European patent application EP And 982 288. It is preferable allocation of acrylic acid is carried out as shown in the in the international application WO/0196271 7, respectively, as described in the German patent application DE-A 102004032129 and its analogues. Optimal methods of extraction of acrylic acid are also described in international applications WO 04/063138 and WO 04/35514, as well as in the German patent applications DE-A 10243625 and DE-A 10235847. Further is pererabotka allocated mentioned acrylic acid can be performed, for example, in accordance with international applications WO 01/77056, WO 03/041832, WO 02/055469, WO 03/078378 and WO 03/041833.

As mentioned at the beginning of the present description, the common feature of these methods for the isolation of target products is that in the head part of distillation columns (with increasing separation efficiency inline elements), in the lower part of which is after usually implemented prior to direct and/or indirect cooling of the injected gas mixture of reaction products, usually formed of the residual gas stream, which mainly contains the components of the gas mixture of the reaction products with a boiling point at normal pressure (1 bar), component ≤-30°C (i.e. hard condensed, respectively volatile components).

In the lower part of the distillation columns typically accumulate volatile ingredients of the components of the gas mixture of the reaction products In the form containing the appropriate target product of the condensed phase.

Components of the residual gas mixture are primarily propane, if necessary neprevyshenie on stage partial oxidation of propylene, molecular oxygen, and often additionally used at the stage of partial oxidation inert diluting gases such as nitrogen and carbon dioxide. Depending on the methods, COI is lsemaj for separation of residual gas, it can contain only traces of water vapor or water vapor content can reach 20% vol. or more.

According to the invention at least part of such major residual gas (preferably having the composition of the residual gas, which contains propane, molecular oxygen and, if necessary, neprevyshenie propylene (preferably the entire quantity, but also only half, two thirds or three quarters of the total number), recycle to the reaction zone as a gaseous source stream 2. However, a partial quantity of the residual gas can be recycled one or both phase partial oxidation and/or subjected to combustion to produce energy.

As indicated in the present description and in the European patent application EP-A 117146, application for U.S. patent US-A 3161670 and German patent applications DE-A 3313573 and DE-A 10316039 before using residual gas as a gaseous source stream 2 from it, obviously, can also partially or fully highlight first of all the components that differ from propane, propylene and molecular oxygen.

During processing of the condensed phase, carried out with the aim of identifying therein the target product may be formed of other residual gases, because usually streets is to return to the reaction zone and regenerated in the system for the allocation of target products all number neprevyshenie propane, contained in the gas mixture of the reaction products Century. Although such other residual gases typically contain propane, and optionally propylene, however, the molecular oxygen is often lacking. Usually they are combined with the main residual gas, getting the total residual gas, which is returned to the reaction zone as a gaseous source stream 2. However, it is also possible to separate the processing of other residual gases, according to their independent recycling to the reaction zone A.

Thanks mostly full recirculation overall residual gas can be implemented continuous conversion of propane to acrylic acid and/or acrolein.

It is important that through the specified recycling and implemented according to the invention the mode of operation of the reaction zone And the opportunity of turning fresh propane to propylene in this zone, the selectivity of which reaches almost 100%.

The benefits of specified technological regime can be implemented both for low (≤30 mol.%), and high (≥30 mol.%) degrees dehydrogenation of propane (in terms of its single pass through the reaction zone A). According to the invention for securing the interaction of oxygen with hydrogen (combustion whom I last with the formation of water) in the General case favorably, to the hydrogen content in the stream source of the reaction gas mixture And was, in at least stoichiometric with respect to the information contained in this stream of oxygen.

In this place of the present description, it should again be noted that the acrylic acid is preferably separated from the obtained according to the invention the gas mixture of the reaction products In the method, in accordance with which the column containing facilitate the separation of built-in items, exercise (e.g., spontaneous) fractionation condensation, if necessary, subjected previously to direct and/or indirect cooling of the gas mixture of the reaction products In a side selection of the crude acrylic acid and/or absorption of acrylic acid with water, respectively, aqueous solution, as described in the examples of the international application WO 2004/035514 and German patent application DE-A 10243625. Selected crude acrylic acid is further preferably subjected to a suspension crystallization and the resulting suspension crystallized acrylic acid is separated from the remaining mother lye preferably the processing in the washing column. The wash liquid is preferably used melt pre-allocated in the wash column crystals of acrylic acid. In addition, preferred is what I use a wash column with forced transport of the crystal layer. Especially preferred is the use of hydraulic or mechanical wash column. Relevant details are given in the international application WO 01/77056, WO 03/041832 and WO 03/041833. Thus, the remaining uterine liquor preferably recycle on stage fractionation condensation (see also European patent application EP-A 1015410). The side components are typically output in the form of a flushing stream lower side selection crude acrylic acid.

Thanks to the use of a single stage crystallization can be obtained acrylic acid purity, component ≥99,8%by weight, which is perfectly suitable for the production of superabsorbents based on polyacrylate sodium.

The example and the comparative example (structural material special steel 1.4841)

I. General structure and mode of operation of the reaction zone And

Heterogeneously catalyzed partial propane dehydrogenation is carried out in shown in figure 4 loop shelf reactor positions, the values of which are indicated in the following description.

Equipped with thermal protection (10) a vertical tubular reactor (11) with an inner diameter of 80 mm placed in a rigid heater (9) (it is possible to operate the reactor in a predominantly adiabatic regime). The temperature of the heater is hard to 500°is. In the middle part of the tubular reactor is a Central tube with an outer diameter of 20 mm, consisting of a sleeve to be inserted thermocouples and thermowells for step thermocouple. To a tubular reactor is additionally attached to the pipe on which it is possible to carry out sampling of the reaction gas and the dosage of air.

The tubular reactor is equipped with three shelves (5, 6, 7) with three identical corresponding bulk layers that are on the wire mesh of stainless steel, each of which, in turn, consists of the following layers (in the direction of transmission of gas flow); the layer of inert material with a height of 100 mm, consisting of staticobj balls with a diameter of from 1.5 to 2.5 mm, and the layer height 165 mm, consisting of a mixture of the dehydrogenation catalyst with steatite balls of diameter 1.5-2.5 mm (volume ratio of these components is 1:1). Thus the total height of each of the cards on the shelves of bulk layers is 265 mm

The dehydrogenation catalyst of General formula Ptfor 0.3Snfor 0.6La3,0Cs0,5Kof 0.2(ZrO2)88,3(SiO2)7,1is containing oxidized elements (cesium (Cs), potassium (K) and lanthanum (La)alloy of platinum with tin deposited on the inner and outer surface of the rods of the carrier, consisting of a mixture of oxides ZrO2·SiO2(media is Yaya height 6 mm, the Gaussian distribution in the interval from 3 to 12 mm with a maximum of about 6 mm; diameter 2 mm), and these elements (including the media) are the stoichiometric mass ratio (preparation of pre-catalyst and its activation to form the active catalyst made in accordance with example 4 of German patent application DE-A 10219 879).

Before each shelf with the catalyst is the mixing element.

Filtered through the last shelf gas mixture of reaction products And (12) is divided into two halves of identical composition. One half (2) (partial thread 1 gas mixture of the reaction products (A) return to dehydration as a component stream of the source of the reaction gas mixture And (4). The other half (1) (partial flow 2 gas mixture of the reaction product (A) is removed from the dehydrogenation zone (reaction zone).

Stream source of the reaction gas mixture And (4) consists of a gaseous source stream 1 (2), as well as from gaseous source of the mixed stream (3), which, in turn, consists of water vapor, residual gas from phase partial oxidation, fresh propane and molecular hydrogen. Original mixed flow (3) performs the function of a work flow jet pump, which, as described above, divides the flow of the gas mixture of the reaction products And (12) on the ve half and creates a stream source of the reaction gas mixture And (4).

The flow passed through the catalyst propane (in terms of the total number found on the shelves of the catalyst excluding inert material) is 350 nl/l·h

The flow pressure of the source of the reaction gas mixture And at the entrance to the reactor is 2.3 bar. The temperature of the reaction stream is 500°C. the pressure Loss by passing the reaction stream through the dehydrogenation reactor is about 200 mbar. Before the second and third bulk catalyst (more precisely, before the respective mixing elements) in the direction of pass of the reaction gas mixture there was added the air, whose temperature is 500°C and pressure corresponds to the pressure in the reactor. Air consumption calculated so that the maximum temperature in the corresponding bulk catalyst layer was in the range of from 575 to 580°C.

II. The General construction and mode of operation of the zone heterogeneously catalyzed two-stage partial oxidation of propylene to acrylic acid

The first reaction stage

The reaction tube (V2A steel, outer diameter 30 mm, wall thickness 2 mm, internal diameter 28 mm, length 350 cm), equipped with a centered sleeve with an outer diameter of 10 mm for mounting of a thermocouple, which allows to measure the temperature along the entire length of the reaction the tube, fill in the following way (top to bottom).

Section 1:length 50 cm; rings made of steatite with dimensions of 7×7×4 mm (external diameter × length × internal diameter) as a preliminary bulk layer.
Section 2:length 140 cm; bulk layer of a homogeneous mixture consisting of 20 wt.%(in another embodiment, 30 wt.%) rings made of steatite with dimensions 5×3×2 mm (external diameter × length × internal diameter) and 80 wt.%(in another embodiment, 70 wt.%) a solid catalyst, similar loaded in section 3.
Section 3:length 160 cm; bulk annular layer of solid catalyst with dimensions 5×3×2 mm (external diameter × length × internal diameter) according to example 1 of German patent application DE-A 10046957 (stoichiometric composition [Bi2W2O9×2WO3]0,5[Mo12Co5,5Fe2,94Si1,59K0,08Ox]1); Alternatively, you can also use one of the catalysts BVK1 - BVK11 from the description of the invention No. 497012 from 29.08.2005.

The first 175 cm reaction tube (in the direction from top to bottom) thermostatic through the counter-flow circulation pump salt RA is Plava A. The following 175 cm reaction tube thermostatic through the pump counter-current circulation of the molten salt Century

The second reaction stage

The reaction tube (V2A steel, outer diameter 30 mm, wall thickness 2 mm, internal diameter 28 mm, length 350 cm), equipped with a centered sleeve with an outer diameter of 10 mm for mounting of a thermocouple, which allows to measure the temperature along the entire length of the reaction tube, fill in the following way (top to bottom).

Section 1:length 20 cm;
rings made of steatite with dimensions of 7×7×4 mm (external diameter × length × internal diameter) as a preliminary bulk layer.
Section 2:length 90 cm;
a bulk layer of a homogeneous mixture consisting of 25 wt.% (in another embodiment, 30 wt.%) rings made of steatite with dimensions of 7×3×4 mm (external diameter × length × internal diameter) and 75 wt.% (in another embodiment, 70 wt.%) layered catalyst, similar loaded in section 4.
Section 3:length 50 cm;
a bulk layer of a homogeneous mixture consisting of 15 wt.% (in another embodiment, 20 wt.%) rings made of steatite with dimensions of 7×3×4 mm (external diameter × length × internal diameter) and 85 wt.% (in another embodiment, 80 wt.%) layered catalyst, similar loaded in section 4.
Section 4:length : 190 cm;
bulk annular layer of the layered catalyst with dimensions of 7×3×4 mm (external diameter × length × internal diameter) according to example 5 of German patent application DE-A 10046928 (stoichiometric composition MO12V3W1,2C2,4Ox).

The first 175 cm reaction tube (in the direction from top to bottom) thermostatic through the pump counter-current circulation of the molten salt C. the Following 175 cm reaction tube thermostatic through the pump counter-current circulation of the molten salt D.

III. The method of obtaining acrylic acid from propane in the new pilot plant (synthesis in stationary mode)

In the first catalyst bed shelf reactor specified in section I, enter the stream source of the reaction gas mixture And having the following composition (vol.% in terms of the total mixture):

vol.%
acrylic acid0,01
acetic acid0,015
water9,23
1-butene0,01
isobutylene0,02
propane18,46
propylene3,98
Ethan1,16
ethylene0,22
carbon dioxide2,34
carbon monoxide0,26
nitrogen59,7
oxygen1,62
methane0,12
hydrogen2,83.

The specified stream source of the reaction gas mixture And form (get) in the following sequence: residual gas (23°C, 3,1 bar), fresh propane, (25°C, 4 bar), hydrogen (25°C, 8 bar), water vapor (200°C, 2.5 bar), d is insulinaemia from the stage dehydrogenation gas (600°C, 1.9 bar), and these components are used in the following quantities:

41,9% vol. residual gas phase partial oxidation (gaseous source stream 2), which has the following structure:

vol.%
acrylic acid0,02
acetic acid0,04
hydrogen2,73
isobutylene0,01
acrolein0,05
propane17,30
propylene0,32
Ethan1,20
ethylene0,22
carbon dioxide2,41
carbon monoxide0,61
nitrogen71,21
oxygena 3.87;

3,9% vol. fresh propane (gaseous source stream 3), the cat is who has the following structure:

vol.%
propane98,91
isobutane0,05
propylene0,1
Ethan0,92
ethylene0,01;

1,02% molecular hydrogen (gaseous source stream 4);

2,03% vol. water vapor (gaseous source stream 5) and

51,15% vol. recycled from the stage dehydrogenation gas partial stream 1 gas mixture of reaction products And, accordingly, the gaseous source stream 1).

In this case the residual gas, fresh propane, hydrogen and water vapor are combined in the above sequence, receiving a mixed workflow, the temperature of which is due to indirect heat exchange with a partial flow 2 gas mixture of reaction products And 500°C, a pressure of 2.3 bar.

The resulting dehydrogenation partial flow 2 gas mixture of reaction products And has the following structure:

vol.%
odor is d 11,84
isobutylene0,01
propane14,32
propylene7,52
Ethan1,21
ethylene0,26
carbon dioxide2,61
nitrogen58,41
oxygen0,23
hydrogen3,55.

Propane and propylene contained in the partial flow 2 gas mixture of reaction products And allocate absorption using as the absorbent technical tetradecane type PKWF 4/7 company Haltermann (Germany) and otparivat by air (to extract these hydrocarbons using the method described in the German patent application DE-A 102004032129), getting sent to the stage partial oxidation gas, which has the following structure:

vol.%
hydrogen2,39
tetradecane 0,01
isobutylene0,01
propanebr15.15
propylene7,95
Ethan1,10
ethylene0,20
carbon dioxide1,05
nitrogen56,99
oxygen15,16

The above gas mixture (she has an explosive composition) is directed to the above first stage partial oxidation. Consumption of propylene through a stationary catalyst bed is 185 nl/l·hour, a Pressure of the gas mixture at the inlet to the first stage reaction is 3.1 bar. The temperature in the reaction zone And (TA) is 322°C, in the reaction zone (TB) 328°C.

The gas mixture of the reaction products formed in the first stage partial oxidation, has the following composition:

vol.%
acrylic acid0,46
acetic acid0,14
hydrogen10,65
1-butene0,01
acrolein6,99
propane15,16
propylene0,17
Ethan1,10
ethylene0,20
carbon dioxide1,62
carbon monoxide0,23
nitrogen57,02
oxygen6,25.

Conversion of propylene at the end of the reaction zone A (UPA) is 64.5 mol.%.

Conversion of propylene at the end of the reaction zone In (UPB) is 94,9 mol.%.

To the product gas mixture of the first reaction stage, add air with a temperature of 25°C. in an amount such that the molar ratio of oxygen to acrolein in the formed mixture was 1.25:1.

The resulting mixture, the temperature of which is 231,7°C, refer directly to the second stage of actiongo oxidation.

Consumption of acrolein passed through the stationary layer of an appropriate catalyst, is 152 nl/l·h

The temperature in the reaction zone And (TC) is 263°C, in the reaction zone D (TD) 269°C. the Pressure of the reaction mixture at the inlet to the second stage is 2.1 bar.

Formed in the second stage, the gas mixture of the reaction product has the following composition:

vol.%
acrylic acid6,72
acetic acid0,22
hydrogen11,06
formaldehyde0,14
acrolein0,05
formic acid0,03
maleic anhydride0,06
benzoic acid0,01
propane14,62
propylene0,28
Ethan1,02
ethylene0,18
carbon dioxide2,03
carbon monoxide0,52
nitrogen59,86
oxygen3,20
propionic acid0,0032.

Conversion acrolein at the end of the reaction zone (UAC) is 68,1 mol.%.

Conversion acrolein at the end of the reaction zone D (UAD) is of 99.3 mol.%.

The reaction gas mixture at both stages of partial oxidation is passed through the contact tube in the downward direction.

The content of individual components is determined by the gas chromatography method.

Acrylic acid is recovered from the gas mixture of the reaction products, as described in the examples of implementation of the German patent application DE-A 102004032129, and residual gas recycle on stage heterogeneously catalyzed dehydrogenation of propane as a gaseous source stream 2.

The method can be also carried out in the manner described above, however, in the reaction zone And each of the shelves load only the same amount of catalyst dehydrogenation, i.e. be the sharing diluting the catalyst with inert material.

IV. Modification of the method described in section III with increasing duration of operation of the experimental setup

With increasing duration of operation of the experimental setup despite the execution of the regeneration of the dehydrogenation catalyst or its replacement with fresh catalyst is a decrease in the content of propylene in the gaseous stream of the mixture of reaction products A.

At the same time ascertain the reduction of the maximum temperature in the first fixed catalyst bed shelf of the reactor (in the direction of transmission of the gas stream).

The initial results of the dehydrogenation can be back due to the operation of the experimental setup, involving formation of a mixed workflow in the following sequence: residual gas, fresh propane, water vapor (in the case of indirect heat exchange) and only after that molecular hydrogen.

1. The method of producing acrolein, acrylic acid, or a mixture thereof from propane, in accordance with which
(A) for entry into the first reaction zone And serves the incoming flow of the reaction gas mixture As obtained by the Association, at least four differing from each gas source flows 1, 2, 3 and 4, and a gaseous source streams 1 and 2 contain propane, gaseous source stream 4 is the molecular bodoro the Ohm, and gaseous source stream 3 is fresh propane,
the incoming flow of the reaction gas mixture And pass at least one catalyst bed of the first reaction zone And in which, if necessary, when applying other gas flows in the heterogeneously catalyzed partial dehydrogenation of propane produces a product stream of a gas mixture containing propane and propylene,
the product stream of the gas mixture And is removed from the first reaction zone And through the corresponding release, thus dividing it into two partial stream 1 and 2 products of the gas mixture And of identical composition, and a partial stream 1 product gas mixture And return to the first reaction zone as a gaseous source stream 1,
a partial stream 2 product gas mixture And, if necessary, send in the first separation zone And in which a separate part or more components contained in it, different from propane and propylene, resulting receive the flow of product gas mixture a', containing propane and propylene,
C) a partial stream 2 product gas mixture a or the flow of product gas mixture a' is used in the second reaction zone to supply at least one oxidation reactor, which is contained in the partial stream 2 product gas mixture a or ow g the gas mixture a' propylene is subjected to a selective heterogeneously catalyzed partial gas-phase oxidation by molecular oxygen, receiving the stream of product gas mixture containing acrolein, acrylic acid or their mixture as the target product, neprevyshenie propane and, if necessary, neprevyshenie propylene, and excess molecular oxygen,
the product stream of the gas mixture withdrawn from the reaction zone Into the second separation zone To separate the contained target product, and at least part of the resulting after separation of the residual gas containing neprevyshenie propane, molecular oxygen and, if necessary, neprevyshenie propylene, as a gaseous source stream 2 return to the reaction zone with a gaseous source streams 2, 3 and 4, and, if necessary, additional gas source flows that differ from the gaseous stream source 1, are combined into a gaseous stream of the working mixture, then this gaseous flow of working fluid as the working flow to operate the jet pump having a nozzle, a mixing section, a diffuser and suction nozzle, and moving the worker thread, drosselweg through the nozzle, a mixing section and diffuser, to the input of the first reaction zone A, and the suction action of the suction nozzle is in the direction of either a thread exit product gas mixture And from the first the second reaction zone A, and at the same time, due to being created in the suction pipe of the vacuum separation of the product stream of the gas mixture And the two partial stream 1 and 2, is the absorption of a partial stream 1 product gas mixture a, it moves through the diffuser while mixing with a work flow in the mixing section and the inlet formed by this reaction flow of the gas mixture And place of its entry into the first reaction zone And,
characterized in that
first form a gaseous source mixed flow, bringing in an arbitrary sequence gaseous source streams 2 and 3, and, if necessary, additional gas source flows that differ from the gaseous source streams 1 and 4, and only after that to the generated gaseous source mixed flow type gaseous source stream 4, receiving mixed gaseous working stream.

2. The method according to claim 1, characterized in that the initial flow of the reaction gas mixture And form a Union of five differing from each gas source flows 1, 2, 3, 4 and 5, the gaseous source stream 5 is water vapor.

3. The method according to claim 2, characterized in that the Association gaseous source flows that differ from the gaseous source streams 1 and 4, in a gaseous source mixed n the current is carried out in the following sequence: gaseous source stream 2, gaseous source stream 5 and then gaseous source stream 3.

4. The method according to one of claims 1 to 3, characterized in that the time interval between the moment of formation of the gaseous flow of the working mixture and after reaching the incoming flow of the reaction gas mixture And the first in its direction of movement of the catalyst bed of the reaction zone And does not exceed 30 C.

5. The method according to one of claims 1 to 3, characterized in that the time interval between the moment of formation of the gaseous flow of the working mixture and after reaching the incoming flow of the reaction gas mixture And the first in its direction of movement of the catalyst bed of the reaction zone And does not exceed 10 C.

6. The method according to one of claims 1 to 3, characterized in that the reaction zone And is shelf reactor.

7. The method according to one of claims 1 to 3, characterized in that the partial heterogeneously catalyzed dehydrogenation of propane in the reaction zone And is carried out in autothermal mode.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: initial mixture 2 of the reaction gas which contains propylene and molecular oxygen, as well as molecular nitrogen and propane as inert gases - diluents, in which molar ratio of molecular oxygen to propylene O2:C3H6≥1, at high temperature is passed through a fixed catalyst bed, the active mass of which is at least one polymetallic oxide containing Mo, Fe and Bi, in which the initial mixture 2 of the reaction gas, per total volume, contains 7-9 vol. % propylene, 9.8-15.5 vol. % molecular oxygen, 10.5-15.5 vol. % propane and 40-60 vol. % molecular nitrogen, provided that the molar ratio V1 of propane contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.5 and 2.2, molar ratio V2 of molecular nitrogen contained in the initial mixture 2 of the reaction gas to molecular oxygen contained in the initial mixture 2 of the reaction gas is between 3.5 and 4.5, and molar ratio V3 of molecular oxygen contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.4 and 2.14.

EFFECT: improved method of lowering flash point temperature of a fixed catalyst bed during synthesis of acrolein or acrylic acid or mixture thereof through heterogeneously catalysed gas-phase partial oxidation of propene.

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FIELD: chemistry.

SUBSTANCE: present invention relates to a method of lowering the flash point temperature of a fixed catalyst bed during synthesis of acrylic acid through heterogeneously catalysed gas-phase partial oxidation of propylene, in which a) at the first reaction step, propane undergoes heterogeneously catalysed dehydrogenation to obtain a product gas mixture 1, b) a partial amount of components in the formed product mixture 1 which are different from propane and propylene are converted to other compounds if needed and if needed a partial amount of components of the product gas mixture 1 formed at the first reaction step which are different from propane and propylene are separated, wherein a product gas mixture 1', which contains propane and propylene, as well as compounds different from oxygen, propane and propylene, is obtained from the product gas mixture 1, and c) as a component of the initial reaction gas mixture 2 at the second reaction step, the product gas mixture 1 or 1' undergoes heterogeneously catalysed partial oxidation in the gas phase of propylene contained in the product gas mixture 1 or 1' to acrolein, where the product gas mixture 2 is obtained, and d) temperature of the product gas mixture leaving the second reaction step, if needed, is lowered through direct and/or indirect cooling and molecular oxygen and/or inert gas is added to the said mixture 2 if needed, and e) further, as an initial reaction gas mixture 3 at the third reaction step, acrolein contained in the initial reaction gas mixture 3 undergoes heterogeneously catalysed gas-phase partial oxidation to acrylic acid, where the product gas mixture 3 is obtained, and f) acrylic acid and at least unreacted propane and propylene contained in the product gas mixture 3 are separated from the product gas mixture 3 in a separation zone A an then returned to at least the first of three reaction steps, where i) the second reaction step is carried out until achieving propylene degree of conversion Up ≤99 mol % for one-time passage through the zone, and ii) the third reaction step is carried out until achieving acrolein degree of conversion UA ≥96 mol % for one-time passage through the zone. The method involves at least one separate selection for components different from propane and propylene, which contains propane and propylene in amount ≤5 vol %.

EFFECT: low temperature.

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FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing acrylic acid from propylene, involving a first step where propylene is oxidised to acrolein and a second step where acrolein is oxidised to acrylic acid, as well as a step for dehydrating glycerin to acrolein in the presence of a propylene-containing gas. The said step for dehydrating glycerin is carried out before catalytic oxidation of propylene to acrolein in the presence of the supplied propylene-containing gas, or after catalytic oxidation of propylene to acrolein in the presence of a gaseous mixture coming out after oxidation of propylene to acrolein.

EFFECT: method enables partial use of renewable material, while increasing output of acrylic acid.

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SUBSTANCE: in accordance with the method A) at least two propane-containing gas supply streams are fed into the first reaction zone A, where at least one of the said streams contains fresh propane, and propane fed into this reaction zone undergoes heterogeneous catalytic dehydrogenation with a fixed bed catalyst, obtaining a propane- and propylene-containing gaseous mixture of products A, B) which is extracted from reaction zone A, in the first separation zone, A is separated from at least a portion of components contained in it, which are different from propane and propylene, and the remaining gaseous mixture of products A' which contains propane and propylene C) is used in the second reaction zone B for supplying at least one oxidation reactor, and propylene contained in the gaseous mixture of products A' in at least one oxidation reactor undergoes heterogeneous catalytic two-step gas-phase partial oxidation with molecular oxygen to acrylic acid or a mixture of acrolein and acrylic acid as an end product, as well as to an excess molecular oxygen-containing gaseous mixture of products B, D) which is extracted from the reaction zone B, in the second separation zone B, the end product contained in it is extracted through absorption or fractional condensation, and at least a portion of the remaining residual gas which contains unconverted propane, molecular oxygen, and also if necessary, unconverted propylene are recycled into the reaction zone A as at least one of two propane-containing supply streams, where the said recycling into the reaction zone A is done along the path of the heterogeneous catalysed dehydrogation of propane in that reaction zone such that, at the point for feeding the recycled gas into reaction zone A at least 5 mol % of propane has already undergone dehydrogenation, where the said propane is fed into this reaction zone with other supply streams, where molar ratio of the propylene contained in the reaction gaseous mixture to molecular hydrogen contained in the said mixture within the reaction zone A does not exceed 10.

EFFECT: design of an improved method of obtaining acrolein, acrylic acid or their mixture from propane.

41 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of continuous, heterogeneous, catalytic, partial gas-phase oxidation of at least one organic compound selected from a group comprising propene, acrolein, isobutene, methacrolein, isobutene and propane, in an oxidation reactor loaded with a gas mixture which, along with at least one compound to undergo partial oxidation and molecular oxygen as an oxidation agent, includes at least one diluent gas which is essentially inert in conditions of heterogeneous, catalytic, gas-phase partial oxidation, where the source of oxygen and inert gas for the loaded gas mixture is air which is compressed in a compressor beforehand from a low initial pressure value to a high final pressure value, where before entering the compressor, the air undergoes at least one mechanical separation procedure through which particles of solid substance dispersed in the air can be separated.

EFFECT: method prevents negative effect of solid particles on the air compression stage, undesirable increase in pressure loss and reduction of activity or selectivity of the catalyst.

21 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method for prolonged heterogeneously catalysed partial oxidation of propene to acrylic acid in gaseous phase, in which the initial gaseous reaction mixture 1, containing propene, molecular oxygen and at least one inert gas, where molecular oxygen and propene are in molar ratio O2:C3H6≥1, is first passed through a fixed catalyst bed 1 at high temperature at the first stage of the reaction, where the active mass of the catalysts is at least one multimetal oxide, containing molybdenum and/or tungsten, as well as at least one element from a group consisting of bismuth, tellurium, antimony, tin and copper, so that, conversion of propene in a single passage is ≥93 mol % and associated selectivity of formation of acrolein, as well as formation of acrylic acid by-product together is ≥90 mol %, temperature of the product gaseous mixture 1 leaving the first reaction stage is reduced if necessary through direct and/or indirect cooling, and if necessary, molecular oxygen and/or inert gas is added to the product gaseous mixture 1, and after that, the product gaseous mixture 1, acting as initial reaction mixture 2, which contains acrolein, molecular oxygen and at least one inert gas, where molecular oxygen and acrolein are in molar ratio O2:C3H4O≥0.5, is passed through a second fixed catalyst bed 2 at high temperature at the second reaction stage, where the active mass of the catalysts is at least one multimetal oxide, containing molybdenum and vanadium so that, conversion of acrolein in a single passage is ≥90 mol % and selectivity of the resultant formation of acrylic acid at both stages is ≥80 mol % in terms of converted propene, and temperature of each fixed catalyst bed is increased independently of each other. Partial oxidation in gaseous phase is interrupted at least once and at temperature of fixed catalyst bed 1 ranging from 250 to 550°C and temperature of fixed catalyst bed 2 ranging from 200 to 450°C, gaseous mixture G, which consists of molecular oxygen, inert gas and water vapour if necessary, is first passed through fixed catalyst bed 1, and then, if necessary, through an intermediate cooler and then finally through fixed catalyst bed 2, in which at least a single interruption takes place before temperature of the fixed catalyst bed 2 increases by 8°C or 10°C, wherein prolonged increase of temperature by 8°C or 10°C, is possible when virtual passage of temperature of the fixed catalyst bed in the period of time on the leveling curve running through the measuring point using the Legendre-Gauss method of the least sum of squares of errors, temperature increase of 7°C or 10°C is achieved.

EFFECT: method increases service life of catalyst.

24 cl, 1 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to improvement of the method of producing (meth)acrylic acid or (meth)acrolein through gas-phase catalytic oxidation of at least one oxidisable substance, chosen from propylene, propane, isobutylene and (meth)acrolein, molecular oxygen or a gas, which contains molecular oxygen, using a multitubular reactor, with such a structure that, there are several reaction tubes, with one (or several) catalytic layer (catalytic layers) in the direction of the axis of the tube, and a coolant can flow outside the said reaction tubes so as to regulate temperature of reaction, in which temperature of the said reaction of gas-phase catalytic oxidation is increased by varying temperature of the coolant at the inlet for regulating temperature of the reaction, while (1) temperature of coolant at the inlet for regulating temperature of the reaction is varied by not more than 2°C for each variation as such, and (2) when variation is done continuously, the time interval from the variation operation, directly preceding the present, is not more than 10 minutes, and, in addition, the difference between the maximum value of peak temperature of reaction of the catalyst layer of the reaction tube and temperature of the coolant at the inlet for regulating temperature of reaction is not less than 20°C.

EFFECT: method in which sharp increase of temperature is suppressed even after changing reaction conditions with aim of increasing temperature for improving efficiency, thus preventing catalyst deactivation, and achieving stable output.

3 cl, 5 dwg, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of carrying out heterogenous catalytic partial oxidation in gas phase of acrolein into acrylic acid, during which reaction gas mixture, containing acrolein, molecular oxygen and at least one inert gas-thinner, is passed through having higher temperature catalytic still layer, whose catalysts are made in such way that their active mass contains at least one oxide of multimetal, containing elements Mo and V, and in which during time, temperature of catalytic still layer is increased, partial oxidation in gas phase being interrupted at least once and at temperature of catalytic still layer from 200 to 450°C acrolein-free, containing molecular oxygen, inert gas and, if necessary, water vapour, as well as, if necessary, CO, gas mixture of G oxidative action is passed through it, at least one interruption being performed before increase of catalytic still layer temperature constitutes 2°C or 4°C or 8°C or 10°C during a long period of time, temperature increase constituting 2°C or 4°C or 8°C or 10°C over a long period of time occurring when in plotting factual course of temperature of catalytic still layer during time on laid through measurement points equation curve according to elaborated by Legendre and Gauss method of the least sum of error squares 2°C or 4°C or 8°C or 10°C temperature increase is achieved.

EFFECT: ensuring spread of hot point with time which is less than in previous methods.

21 cl, 3 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing (met)acrolein and/or (met)acrylic acid through heterogeneous catalytic partial oxidation in gaseous phase, in which a fresh fixed-bed catalyst at 100-600°C in a reactor is loaded with a mixture of loading gas, which along with at least, one C3/C4 organic precursor compound subject to partial oxidation and oxidation with molecular oxygen, contains at least one gas-diluent. The process is carried out after establishing content of the mixture of loading gas at constant conversion of organic precursor compound and at constant content of the mixture of loading gas initially in the input period for 3-10 days with load of 40-80% of higher final load, and then at higher filling load of the catalyst with a mixture of loading gas. In the input period, maximum deviation of conversion of organic precursor compound from arithmetic time-averaged and maximum deviation of the volume ratio of one component of the mixture loading gas, oxidising agent, organic precursor compound and gas-diluent, from the arithmetic time-averaged volume ratio of the corresponding component of the mixture of loading gas should not exceed ±10% of the corresponding arithmetic mean value.

EFFECT: method allows for eliminating shortcomings of previous technical level.

3 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention concerns aggregate for (met)acrylic acid obtainment, including: reactor for (met)acrylic acid obtainment by catalytic gas phase oxidation reaction of one, two or more source compounds including propane, propylene, isobutylene and (met)acrolein, in gas mix of source substances including one, two or more source compounds including propane, propylene, isobutylene and (met)acrolein, and oxygen; heat exchanger connected to reactor and intended for cooling of reaction gas mix including obtained (met)acrylic acid; and absorption column connected to heat exchanger and intended for contact absorbing fluid with reaction gas mix for (met)acrylic acid absorption, so that (met)acrylic acid is absorbed from reaction gas mix by absorbing fluid. Additionally the aggregate includes: bypass pipe connecting reactor and absorption column without the use of intermediary heat exchanger; and device for flow rate adjustment in reaction gas flow passing through bypass pipe in order to maintain almost constant flow rate of gas mix feed of source materials to reactor or almost constant pressure of gas mix of source materials at the reactor inlet. Also invention concerns improved method of (met)acrylic acid obtainment by extraction of (met)acrylic acid absorbed by absorbing fluid.

EFFECT: heat power tapping from reaction gas mix, stable and continuous process even in case of heat exchanger intended for heat power extraction is blocked.

2 cl, 3 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: initial mixture 2 of the reaction gas which contains propylene and molecular oxygen, as well as molecular nitrogen and propane as inert gases - diluents, in which molar ratio of molecular oxygen to propylene O2:C3H6≥1, at high temperature is passed through a fixed catalyst bed, the active mass of which is at least one polymetallic oxide containing Mo, Fe and Bi, in which the initial mixture 2 of the reaction gas, per total volume, contains 7-9 vol. % propylene, 9.8-15.5 vol. % molecular oxygen, 10.5-15.5 vol. % propane and 40-60 vol. % molecular nitrogen, provided that the molar ratio V1 of propane contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.5 and 2.2, molar ratio V2 of molecular nitrogen contained in the initial mixture 2 of the reaction gas to molecular oxygen contained in the initial mixture 2 of the reaction gas is between 3.5 and 4.5, and molar ratio V3 of molecular oxygen contained in the initial mixture 2 of the reaction gas to propylene contained in the initial mixture 2 of the reaction gas is between 1.4 and 2.14.

EFFECT: improved method of lowering flash point temperature of a fixed catalyst bed during synthesis of acrolein or acrylic acid or mixture thereof through heterogeneously catalysed gas-phase partial oxidation of propene.

27 cl, 1 dwg, 3 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of lowering the flash point temperature of a fixed catalyst bed during synthesis of acrylic acid through heterogeneously catalysed gas-phase partial oxidation of propylene, in which a) at the first reaction step, propane undergoes heterogeneously catalysed dehydrogenation to obtain a product gas mixture 1, b) a partial amount of components in the formed product mixture 1 which are different from propane and propylene are converted to other compounds if needed and if needed a partial amount of components of the product gas mixture 1 formed at the first reaction step which are different from propane and propylene are separated, wherein a product gas mixture 1', which contains propane and propylene, as well as compounds different from oxygen, propane and propylene, is obtained from the product gas mixture 1, and c) as a component of the initial reaction gas mixture 2 at the second reaction step, the product gas mixture 1 or 1' undergoes heterogeneously catalysed partial oxidation in the gas phase of propylene contained in the product gas mixture 1 or 1' to acrolein, where the product gas mixture 2 is obtained, and d) temperature of the product gas mixture leaving the second reaction step, if needed, is lowered through direct and/or indirect cooling and molecular oxygen and/or inert gas is added to the said mixture 2 if needed, and e) further, as an initial reaction gas mixture 3 at the third reaction step, acrolein contained in the initial reaction gas mixture 3 undergoes heterogeneously catalysed gas-phase partial oxidation to acrylic acid, where the product gas mixture 3 is obtained, and f) acrylic acid and at least unreacted propane and propylene contained in the product gas mixture 3 are separated from the product gas mixture 3 in a separation zone A an then returned to at least the first of three reaction steps, where i) the second reaction step is carried out until achieving propylene degree of conversion Up ≤99 mol % for one-time passage through the zone, and ii) the third reaction step is carried out until achieving acrolein degree of conversion UA ≥96 mol % for one-time passage through the zone. The method involves at least one separate selection for components different from propane and propylene, which contains propane and propylene in amount ≤5 vol %.

EFFECT: low temperature.

39 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention discloses a method for safe continuous heterogeneous catalysed gas-phase partial oxidation of at least one organic starting compound in a reactor, whose stream of loaded gas mixture along with at least one partially oxidisable organic starting compound and molecular oxygen as an oxidising agent contains at least one diluting gas which remains essentially inert under heterogeneous catalysed gas-phase partial oxidation conditions,and is obtained by merging at least two different initial streams, where through online measurement of concentration of one or more selected components in the stream of the loaded gas mixture in one or more initial streams which form the stream of the loaded gas mixture and/or stream of gas mixture of the product, loading of an uncontrolled stream of gas mixture in terms of explosion risk or other is prevented, wherein for online measurement of the partial stream, the analysed gas stream is accordingly continuously fed into the measurement cell of an analysing device and during measurement, said stream comes out of the measurement cell into the free atmosphere, where the analysed gas stream and/or free atmosphere are subject to pressure fluctuations, where the effect of pressure fluctuation of the analysed gas stream and/or free atmosphere on the measured pressure in the measurement cell in the analysing device and therefore on the measurement resulta) is corrected through calculation, based on properties capable of correlation with the gas in the measurement cell and/or b) is minimised based on that the measured in the measurement cell of the analysing device is kept constant or controlled to a constant value using a pressure regulator, independent of the pressure of the analysed gas stream and/or free atmosphere.

EFFECT: high reliability and safety of the process.

18 cl, 4 ex, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to improved combined methods of producing acetic acid and vinyl acetate involving the following steps: (a) obtaining a first stream of product from the first reaction zone containing acetic acid, where the acetic acid is obtained via an exothermic carbonylation reaction, and where at least part of the heat obtained from the acetic acid is tapped from the first reaction zone and at least part of the heat tapped during production of acetic acid is transferred to a heat exchange system; (b) bringing the reaction stream of acetic acid containing at least a portion of acetic acid from the first stream of product into contact an oxygen-containing gas in a second reaction zone in the presence of a catalyst to obtain a second stream of product which contains vinyl acetate monomer; (c) directing at least a portion of the second stream of product to purification section for purification of at least a portion of vinyl acetate in the second stream of product; and either (d) tapping at least part of heat transferred to the heat exchange system, and delivering at least part of the heat tapped from the heat exchange system to at least one reaction stream of acetic acid and the vinyl acetate purification section, and where the heat exchange system contains a stream of a steam condensate, and where at least part of the heat tapped during production of acetic acid is delivered to the stream of steam condensate which is used to provide at least one reaction stream of acetic acid and the vinyl acetate purification section with heat tapped during production of acetic acid, where the stream of steam condensate containing heat from production of acetic acid is directed to a low-pressure evaporation vessel kept at pressure between 4.0 kg/cm2 and 5.3 kg/cm2, or (d) tapping at least part of the heat transferred to the heat exchange system, and delivering at least part of heat tapped from the heat exchange system to at least one reaction stream of acetic acid and the vinyl acetate purification section, in which a loop is used to cycle the condensate in order to remove most of the heat from production of acetic acid by directing a stream of a hot reaction solution through the heat exchanger for transferring heat to the stream of steam condensate, where the stream of steam condensate which contains heat from production of acetic acid is directed to the low-pressure evaporation vessel kept at pressure between 4.0 kg/cm2 and 5.3 kg/cm2.

EFFECT: proposed methods are useful for lowering expenses and reducing power consumption during vinyl acetate production.

10 cl, 1 dwg

FIELD: oil and gas industry.

SUBSTANCE: invention refers to mixed oxide catalysts for catalytic oxidation of olefins and methylated aromatic compounds in gas phase, to a method for preparing such catalysts and a method for making aldehydes and carboxylic acids. There are described mixed oxide catalysts of general formula I (Mo12BiaCb(Co+Ni)cDdEeFfGgHh)Ox (I), where C means iron, D means P, E means at least one of elements of the group including Li, K, Na, Rb, Cs, F means Mn, G means at least one of elements of the group including Sm, Gd, La, H means at least one of elements of the group including Si, Al, and a means a number 0 to 5.0, b means a number 0.5 to 5.0, c means a number 2 to 15, d means a number 0.01 to 5.0, e means a number 0.001 to 2, f means a number 0.001 to 5, g means a number 0 to 1.5, h means a number 0 to 800, and h means a number determined by the valence and concentration of the elements differing from oxygen. There is described a method for preparing a catalysts of formula (1), where solutions of the compounds found in mixed oxide catalysts of formula of I metals are mixed; cosediment are prepared; a formed solid substance is recovered, dried, baked and if necessary processed to shape as required. There is also described a method for making aldehydes and acids by air or oxygen oxidation of olefins or methylated aromatic compounds in the inert gas, steam or end reaction gas medium at higher temperatures with using described catalyst of general formula (1).

EFFECT: higher activity and selectivity of the catalyst.

25 cl, 14 ex

FIELD: chemistry.

SUBSTANCE: in accordance with the method A) at least two propane-containing gas supply streams are fed into the first reaction zone A, where at least one of the said streams contains fresh propane, and propane fed into this reaction zone undergoes heterogeneous catalytic dehydrogenation with a fixed bed catalyst, obtaining a propane- and propylene-containing gaseous mixture of products A, B) which is extracted from reaction zone A, in the first separation zone, A is separated from at least a portion of components contained in it, which are different from propane and propylene, and the remaining gaseous mixture of products A' which contains propane and propylene C) is used in the second reaction zone B for supplying at least one oxidation reactor, and propylene contained in the gaseous mixture of products A' in at least one oxidation reactor undergoes heterogeneous catalytic two-step gas-phase partial oxidation with molecular oxygen to acrylic acid or a mixture of acrolein and acrylic acid as an end product, as well as to an excess molecular oxygen-containing gaseous mixture of products B, D) which is extracted from the reaction zone B, in the second separation zone B, the end product contained in it is extracted through absorption or fractional condensation, and at least a portion of the remaining residual gas which contains unconverted propane, molecular oxygen, and also if necessary, unconverted propylene are recycled into the reaction zone A as at least one of two propane-containing supply streams, where the said recycling into the reaction zone A is done along the path of the heterogeneous catalysed dehydrogation of propane in that reaction zone such that, at the point for feeding the recycled gas into reaction zone A at least 5 mol % of propane has already undergone dehydrogenation, where the said propane is fed into this reaction zone with other supply streams, where molar ratio of the propylene contained in the reaction gaseous mixture to molecular hydrogen contained in the said mixture within the reaction zone A does not exceed 10.

EFFECT: design of an improved method of obtaining acrolein, acrylic acid or their mixture from propane.

41 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: description is given of a catalyst composition and its use for selective oxidation of ethane to acetic acid and/or for selective oxidation of ethylene to acetic acid, where the said composition combined with oxygen contains molybdenum, vanadium, niobium, gold in the absence of palladium in accordance with the empirical formula: MoaWbAucVdNbeZf, in which Z denotes one or more elements selected from a group comprising Sn, Ag, Fe and Re; a, b, c, d, e and f denote gram-atomic ratios of elements for which 0<a<1; 0<b<1 and a+b=1; 10-5<c≤0.02; 0<d≤2; 0<e≤1 and 0.0001≤f≤0.05. A method is described for synthesis of acetic acid from a gaseous mixture containing ethane and/or ethylene, involving bringing the gaseous mixture into contact with a gas containing molecular oxygen at high temperature in the presence of the catalyst composition described above.

EFFECT: increased selectivity with respect to acetic acid combined with reduced selectivity with respect to ethylene.

13 cl, 1 tbl, 9 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a single-step method for vapour-phase oxidation of an alkane such as propane which leads to production of unsaturated caboxylic acid such as acrylic or methacrylic acid in the presence of a mixed metal oxide catalyst and excess alkane with respect to amount of oxygen. The method of producing unsaturated carboxylic acid involves: (a) reacting alkane and oxygen-containing gas in a reaction zone with a catalyst which contains mixed metal oxide under conditions which enable production of a gaseous product containing unsaturated carboxylic acid, unreacted alkane and an alkene by-product; (b) extraction of unreacted alkane and alkene by-product from the gaseous product; and (c) recycling the mixture of the extracted unreacted alkane and alkene by-product to the reaction zone without separating components; in which the mixed metal oxide consists of material with general formula MoVvAaBbCcOx where Mo is molybdenum, V is vanadium, each of A, B and C represents niobium, antimony, tellurium, silver, tantalum, titanium, aluminium, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, platinum, bismuth, boron, indium, arsenic, germanium, tin, lithium, sodium, potassium, rubidium, caesium, francium, beryllium, magnesium, calcium, stronium, barium, hafnium, lead, phosphorus, promethium, europium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, gold, selenium, palladium, gallium, zinc, praseodymium, rhenium, iridium, neodymium, yttrium, samarium and terbium, v equals 0.1-0.5, a equals 0.01-0.2, b equals 0.0-0.5, c equals 0.0-0.5, value of x is determined by valency of other components, in which alkane is propane or isobutane; where the alkane is in excess relative oxygen and molar ratio alkane: oxygen ranges from 3:1 to 1:1; and in which amount of alkene recycled to the reactor corresponds to the molar ratio alkane: alkene equal to 1:0.03-1:0.1.

EFFECT: improved method.

14 cl, 3 tbl, 1 dwg, 23 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of continuous, heterogeneous, catalytic, partial gas-phase oxidation of at least one organic compound selected from a group comprising propene, acrolein, isobutene, methacrolein, isobutene and propane, in an oxidation reactor loaded with a gas mixture which, along with at least one compound to undergo partial oxidation and molecular oxygen as an oxidation agent, includes at least one diluent gas which is essentially inert in conditions of heterogeneous, catalytic, gas-phase partial oxidation, where the source of oxygen and inert gas for the loaded gas mixture is air which is compressed in a compressor beforehand from a low initial pressure value to a high final pressure value, where before entering the compressor, the air undergoes at least one mechanical separation procedure through which particles of solid substance dispersed in the air can be separated.

EFFECT: method prevents negative effect of solid particles on the air compression stage, undesirable increase in pressure loss and reduction of activity or selectivity of the catalyst.

21 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method for prolonged heterogeneously catalysed partial oxidation of propene to acrylic acid in gaseous phase, in which the initial gaseous reaction mixture 1, containing propene, molecular oxygen and at least one inert gas, where molecular oxygen and propene are in molar ratio O2:C3H6≥1, is first passed through a fixed catalyst bed 1 at high temperature at the first stage of the reaction, where the active mass of the catalysts is at least one multimetal oxide, containing molybdenum and/or tungsten, as well as at least one element from a group consisting of bismuth, tellurium, antimony, tin and copper, so that, conversion of propene in a single passage is ≥93 mol % and associated selectivity of formation of acrolein, as well as formation of acrylic acid by-product together is ≥90 mol %, temperature of the product gaseous mixture 1 leaving the first reaction stage is reduced if necessary through direct and/or indirect cooling, and if necessary, molecular oxygen and/or inert gas is added to the product gaseous mixture 1, and after that, the product gaseous mixture 1, acting as initial reaction mixture 2, which contains acrolein, molecular oxygen and at least one inert gas, where molecular oxygen and acrolein are in molar ratio O2:C3H4O≥0.5, is passed through a second fixed catalyst bed 2 at high temperature at the second reaction stage, where the active mass of the catalysts is at least one multimetal oxide, containing molybdenum and vanadium so that, conversion of acrolein in a single passage is ≥90 mol % and selectivity of the resultant formation of acrylic acid at both stages is ≥80 mol % in terms of converted propene, and temperature of each fixed catalyst bed is increased independently of each other. Partial oxidation in gaseous phase is interrupted at least once and at temperature of fixed catalyst bed 1 ranging from 250 to 550°C and temperature of fixed catalyst bed 2 ranging from 200 to 450°C, gaseous mixture G, which consists of molecular oxygen, inert gas and water vapour if necessary, is first passed through fixed catalyst bed 1, and then, if necessary, through an intermediate cooler and then finally through fixed catalyst bed 2, in which at least a single interruption takes place before temperature of the fixed catalyst bed 2 increases by 8°C or 10°C, wherein prolonged increase of temperature by 8°C or 10°C, is possible when virtual passage of temperature of the fixed catalyst bed in the period of time on the leveling curve running through the measuring point using the Legendre-Gauss method of the least sum of squares of errors, temperature increase of 7°C or 10°C is achieved.

EFFECT: method increases service life of catalyst.

24 cl, 1 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing maleic anhydride in a fluidised bed by oxidising material which contains C4 hydrocarbons with molecular oxygen or oxygen-containing gas in a reactor with a fluidised bed at reactor temperature 325-500°C in the presence of a catalyst capable of working in the fluidised bed, containing mixed oxides of vanadium and phosphorus, wherein the catalyst is prepared as follows: (a) preparation of a catalyst precursor containing mixed vanadium and phosphorus oxide; (b) packing the catalyst precursor; (c) crushing the catalyst precursor to particles whose average size is less than one micrometre in diametre; (d) moulding particles which are capable of working in the fluidised bed, with bulk density greater than or equal to 0.75 g/cm3 from the packed crushed catalyst precursor; and (e) annealing said particles in boiling conditions, where output of the maleic anhydride is increased by adding a compensating catalyst into the reactor with the fluidised bed, wherein said compensating catalyst contains alkyl ether of orthophosphoric acid of formula (RO)3P=O, where R is hydrogen or C1-C4 alkyl and at least one R is C1-C4 alkyl, where the compensating catalyst is prepared by saturating the catalyst obtained according to steps (a) to (e) with alkyl ether of orthophosphoric aid. The invention also discloses a method of improving operation of the mixed vanadium-phosphorus oxide catalyst for producing maleic anhydride from butane in a fluidised bed. The invention also relates to a catalyst capable of working in the fluidised bed, for producing maleic acid by oxidising material which contains C4 hydrocarbons.

EFFECT: invention ensures high output of the end product at low working temperatures.

31 cl, 2 tbl, 2 ex

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