Method of (meth)acroleine or (meth)acrylic acid production

FIELD: chemistry.

SUBSTANCE: method of (meth)acrolein or (meth)acrylic acid production is implemented by of catalytic phase oxidation reaction of propane, propylene, isobutylene or (meth)acrolein with oxygen-containing gas. Non-organic salt is used as heat carrier for reaction temperature adjustment. Pipeline for heat carrier feeding has adjustment valve adjusting heat carrier feed and circulation rate and rotating freedom of rotation axis. Rotation axis adjoins case with capability of sliding against each other. Gasket filling material sealing the case of adjustment valve is based on mica.

EFFECT: high-precision temperature adjustment ensuring stable process of gas phase catalytic oxidation.

5 cl, 5 dwg, 2 ex

The technical field

This invention relates to a method of manufacturing (meth)acrolein or (meth)acrylic acid. More specifically, it relates to a method of production of c by using a process in which (meth)acrolein or (meth)acrylic acid effectively get gas-phase catalytic oxidation of propylene, propane or isobutylene with molecular oxygen.

The level of technology

(Meth)acrolein or (meth)acrylic acid is mainly produced by reaction of gas-phase catalytic oxidation of propylene, propane or isobutylene using novotrubnogo reactor and molecular oxygen or a molecular oxygen-containing gas in the presence of a composite oxide catalyst.

In the reference patent 1 (JP-A-8-92147) reveals the way in which the temperature of the cooling fluid (hereinafter called "the carrier") level by regulating the temperature in the reactor between its input and output to values 2-10°C or below by creating in the jacket of reactor coolant flow (parallel to the direction of flow of the reactive gas fed into the reactor, and by creating step of decreasing the coolant flow using guidelines partitions.

Currently there is a lack of proposals concerning the category of equipment for temperature control of the reaction to control the reaction, having a high dissipation.

Reference patent 1: JP-A-8-92147

Description of the invention

Tasks that should be solved by the invention

The purpose of the present invention is to provide a device capable of high-precision temperature control of the reaction, which is the basis for stable holding of the method of gas-phase catalytic oxidation, without deactivation of the catalyst reactor and method for production of (meth)acrolein or (meth)acrylic acid using this reaction.

Novotrubny reactor is mainly used in the method of gas-phase catalytic oxidation, which is a way to obtain the oxidized product of the oxidation reaction, where the solid catalyst is introduced into the reaction zone and introduced into contact with the raw material.

Because novotrubnom reactor a significant number of tubes (pipes) installed mainly vertically, the flow of process fluid can be ascending or descending, depending on the supply of process fluid from the bottom or top flange. The fluid can also be fed into the jacket through the top or bottom flange. Thus, it is possible to consider: 1) a system of parallel flow of process fluid directed downward, and the coolant flow downward; 2) the parallel system in the CMOS process fluid, upward, and the coolant flow is directed upwards; 3) the counter-current system, the fluid upward, and the coolant downward; and 4) the counter-current system, the fluid downward, and the coolant upward.

In this novotrubnom the reactor temperature required for the reaction, is maintained by circulating temperature-controlled fluid around the outer surface of the package of the reaction tubes (tube area), and at the same time introduces the way in which preventing food poisoning or deactivation of the catalyst in the tubes caused by excessive increase in the temperature of the process fluid (education section of overheating (the active site)), and by the heat exchange between the process fluid (process gas in the case of the reaction of gas-phase catalytic oxidation) and coolant, and, in addition, in chemical plants often used in the heat exchanger.

However, when the reaction gas-phase catalytic oxidation of propylene, propane or isobutylene with molecular oxygen or molecular oxygen-containing gas in the presence of the composite oxide catalyst, the heat of reaction of gas-phase catalytic oxidation is so high that in the many cases, problems arise due to lack of control in many well-known standard designed devices, even when used correctly selected catalyst, for example, the problem of catalyst poisoning caused by a very high temperature, resulting in specific locations catalyst layer, the problem of yield of the reaction under control, caused by exceeding the acceptable temperature of the catalyst, or when the catalyst becomes unsuitable for use.

One reason is that the temperature outside the package of the reaction tube in the annular zone), which is the basis of the industrial equipment, may not be set to the specified value.

The reaction of gas-phase catalytic oxidation is carried out mainly so that the fluid having a high temperature due to absorption of the heat of reaction, is cooled to a predetermined temperature, and then resume its circulation in the reactor, but if the raw material is a (meth)acrolein or (meth)acrylic acid and molecular oxygen or a molecular oxygen-containing gas, to prevent the above-mentioned output control reactions in the catalytic layer of the circulation, as a rule, carried out with the participation of the selected type and quantity of fluid in which it teplovi the bookmark becomes extremely high, that allows you to adjust the temperature difference between the inlet and outlet of the reactor (after the stage of absorption of the heat of reaction) at a level of from 1 to 3°C.

In order to adjust such a small temperature gradient in a large volume of fluid, typically use a heat exchanger and often as the coolant using the nitrate mixture nitrate)due to its temperature, but because nitrate has a high melting point and, therefore, easily hardens, its use causes a failure in operation of valve used for regulating the temperature, making fine adjustment of temperature becomes complicated, and (despite the precision design of the structure of the catalyst and reactor, which can prevent the yield of the reaction under control) in some cases the yield of the reaction of control.

The invention was created in consideration of the existing above-mentioned circumstances, and its purpose is to provide a method for producing (meth)acrolein or (meth)acrylic acid through the implementation of the reaction of gas-phase catalytic oxidation of a raw material for (meth)acrolein or (meth)acrylic acid with molecular oxygen or molecular oxygen-containing gas, which is an industrial production method, which can stably produce the product, of interest, maintaining its quality by exercising the smooth and accurate control of the temperature of the coolant and, therefore, effective prevention of the formation of sites of overheating (hot spots) and, in addition, the aim of the invention is the creation of the appropriate production equipment.

The authors of the present invention explained the way in which use the heat carrier in the oxidation reactor with the purpose of obtaining a (meth)acrylic acid or similar compounds, in which you can eliminate the malfunctions valve installed on the pipeline, and thus, easier to regulate the temperature of the heat carrier or transport of fluid and preventing various outputs reactions under control.

Resolving problems

The objective of the invention was performed using the following tools.

(1) Method of manufacturing (meth)acrolein or (meth)acrylic acid by the reaction of gas-phase catalytic oxidation of propane, propylene, isobutylene or (meth)acrolein oxygen-containing gas using an inorganic salt as a coolant to control the temperature of the reaction, characterized in that the material for gaskets gasket, which seals a part of the enclosure maintains the existing valve, installed on the supply and regulating the flow and speed of circulation of the coolant, and regulating the rotational degree of mobility to the axis of rotation, which is coupled with the valve body so that it may be slipping relative to each other, is a material based on mica.

(2) the Method of manufacturing (meth)acrolein or (meth)acrylic acid is carried out according to the above variant (1), where the design of the gland regulating valve provided by the heating jacket.

(3) the Method of manufacturing (meth)acrolein or (meth)acrylic acid according to the above option (1) or (2), where the drive of the regulating valve in the absence of fluid flow is set relations [sliding friction force between the valve body and an associated rod]/[maximum force drive start]equal to 0.2 or less.

(4) the Method of manufacturing (meth)acrolein or (meth)acrylic acid according to the above variant (1), where the above-mentioned inorganic salt is a nitrate mixture consisting of 53 wt.% KNO₃(potassium nitrate), 40 wt.% NaNO₂(sodium nitrite) and 7 wt.% NaNO₃(sodium nitrate).

(5) a Device for the production of (meth)acrolein or (meth)acrylic acid, which is used in sposaperfetta, described in any of the above options(1)-(4).

The advantage of the invention

The method according to the invention for the production of (meth)acrylic acid and similar compounds, characterized by the use of mica in the valve installed on the pipe of the heat carrier, which is used in the oxidation reactor for the production of (meth)acrolein and/or (meth)acrylic acid. According to the production method according to the invention, the operational failure of the valve is eliminated, and the temperature control of the heat carrier or transporting fluid is facilitated, resulting in a stable and high-quality production becomes possible.

Brief description of drawings

Figure 1 represents a variant embodiment novotrubnogo reactor type heat exchanger according to the invention is used in the method of gas-phase catalytic oxidation,

figure 2 represents another variant embodiment novotrubnogo reactor type heat exchanger, which is used according to the invention in the method of gas-phase catalytic oxidation,

figure 3 is a variant embodiment of the system novotrubnogo reactor type heat exchanger and the heat exchanger used in the invention,

figure 4 represents another variant embodiment of the system novotrubnogo reactor type heat e is mennica and heat exchanger, used in the invention, and

figure 5 is a block diagram of the example control valve used according to the invention in the regulation of the temperature and the brine.

Description of reference numbers and symbols

Reference number 1b and 1c denote the reaction tube, 2 - reactor 3a and 3b annular channels, 4a - outlet for the product, 4b - feed opening, the raw materials 5a and 5b - tube, 6a, and 6b - perforated guides partition, 7 - pump, 8a - pipe coolant, 8b - pipe to release fluid, 9 - intermediate tubular bars 10 and heat - shielding partition wall 15 - thermometer, 20 to the heat exchanger and 21 - regulating valve.

The best way of carrying out the invention

Next is a detailed description of the invention.

The invention is a method of gas-phase catalytic oxidation for the production of (meth)acrolein or (meth)acrylic acid or similar compounds, characterized by the design of the valve, is installed on the pipeline that transports the coolant used in the reactor, in which gas-phase catalytic oxidation.

According to this description of the invention the acrylic acid derived from propylene or the prop is on, and methacrylic acid, derived from isobutylene, if called in a General way, it is usually defined as (meth)acrylic acid.

The reactor may be any reactor with a fluidized bed, or a reactor with a fixed bed, but desirable Novotrubny reactor with a fixed bed.

Further details of the production of (meth)acrolein and (meth)acrylic acid.

[Reaction system]

A selection of typical examples of the industrial mode of production (meth)acrolein and (meth)acrylic acid, including single-pass system, the recycling of unreacted propylene and the recirculated exhaust gas, which is described later, and the reaction system, which includes these three systems described in this invention is not limited.

(1) single-pass system

This system is a method in which propylene, air and steam are mixed, serve and transform, mainly in the (meth)acrolein and (meth)acrylic acid during the live stages of the reaction, and the exhaust gas serves to implement the reverse reaction stage. In this case, the way in which air and steam are required for the implementation of the reverse reaction, is served at this last stage, in addition to exhaust gas from the direct reaction stage, is also common.

(2) recycling unreacted p is cut

This system is a method in which a gaseous reaction product containing (meth)acrylic acid obtained by the reverse reaction, served in the storage device for the (meth)acrylic acid, (meth)acrylic acid accumulates in the aqueous solution, and part of the unreacted propylene recycle by filing a part of the assembled device of exhaust gas containing unreacted propylene, on the site of the execution of direct reaction stage.

(3) the recirculation System exhaust gas

This system is a method in which a gaseous reaction product containing (meth)acrylic acid obtained by the reverse reaction, served in the storage device for the (meth)acrylic acid, (meth)acrylic acid accumulates in the aqueous solution, the entire amount of exhaust gas stored in the storage device, is oxidized by combustion to convert unreacted propylene and the like of the gas contained in the storage device, into carbon dioxide and water, and part of the thus obtained product of the combustion exhaust gas is injected directly step of the reaction.

According to the invention the term "process gas" means gases involved in the reaction of gas-phase catalytic oxidation, such as substance, OK is sleeve as a raw material gas, the molecular oxygen-containing gas, the resulting product, etc.

[Composition of the raw gas]

In Novotrubny reactor serves mainly gas mixture consisting of propylene, propane or isobutylene and/or (meth)acrolein in the form of raw gas, molecular oxygen-containing gas and steam, for use in the reaction of gas-phase catalytic oxidation.

According to the invention the concentration of propylene, propane or isobutylene in the gas mixture ranges from 6 to 10 mol%, oxygen concentration from 1.5 to 2.5 mol the number of moles of propylene, propane or isobutylene, and the concentration of steam is from 0.8 to 5 moles to the number of moles of propylene, propane or isobutylene. The introduced raw material gas is distributed to the respective reaction tubes, passes through the reaction tube and subjected to reaction in the presence contained in the reactor of the oxidation catalyst.

[Novotrubny reactor]

The reaction of gas-phase catalytic oxidation, which is used in novotrubnom the reactor with a fixed bed, is a widely used method for the production of (meth)acrolein or (meth)acrylic acid from propylene or isobutylene with molecular oxygen or molecular oxygen-containing gas in the presence of a composite oxide catalyst.

According to the invention Novotrubny reactor with a porous layer mainly used in industrial scale and has no special restrictions.

For example, possible reactor, consisting of a cylindrical reactor having an inlet for supply of raw materials and an outlet for release of a product, two or more annular channels provided on the peripheral surface of the cylindrical body of the reactor coolant to enter into the housing cylindrical reactor or its output, the circulation device that links together two or more annular channels, two or more reaction tubes, which are supported by two or more tubular plates of the reactor and containing the catalyst, and two or more guide walls for changing the direction of the coolant introduced into the reactor vessel that are located in the longitudinal direction of the reaction pipes.

Furthermore, the method according to the invention the production of (meth)acrolein or (meth)acrylic acid is a method for making gas-phase catalytic oxidation of a substance oxidizable by molecular oxygen-containing gas, and is a way of gas-phase catalytic oxidation, which is carried out when filling out the above reaction tubes with the catalyst on the basis of the Mo-Bi and/or a catalyst based on Mo-V.

The following describes a variant implementation of the invention on the basis of 1, 2 and 5.

Figure 1 shows a reactor of the type m is ohorongo heat exchanger for use in a typical embodiment, the method of gas-phase catalytic oxidation according to the invention. In figure 1 the reaction tube 1b and 1c are attached to the tube gratings 5a and 5b and is installed in the housing 2 novotrubnogo reactor. Hole 4a or 4b, which becomes the intake of raw materials as an input channel for the raw material gas to a reaction or a hole for the release of the product as the output channel for the product, installed on the top or bottom of the housing 2, with one hole becomes the intake of raw materials, and the other hole for the release of the product, depending on flows if the process gas up or down. When the process gas stream is counter against the flow of the coolant hole 4b is a hole for the release of raw materials, since the direction of flow of the coolant inside the reactor vessel shown in figure 1 by the arrow as the upward flow. However, the direction of flow of the process gas can be any. The annular channel 3a coolant to enter is located on the peripheral surface of the housing 2 of the reactor. The fluid pumped by the circulation pump 7, rises inside the housing 2 of the reactor from the annular channel 3a, and then returns to the circulating pump 7 of the annular channel 3b due to the change in the direction of its flow, caused by alternating two or more perforated guides, perehara is OK 6a, having a hole within the Central part of the housing 2 of the reactor, and perforated rails partitions 6b installed in such a way that they have a hole between the peripheral part of the system and the housing 2 of the reactor. Part of the coolant that has absorbed heat of reaction, is cooled using a heat exchanger (cf. figure 3), due to the pipeline 8b to release fluid that is installed on the upper part of the circulating pump 7 and then introduced into the reactor from the pipeline 8a coolant. The heat carrier temperature adjustment is performed by adjusting the temperature or flow rate of the circulating fluid supplied from pipe 8a coolant, while watching thermometer 14 and in accordance with the temperature data.

Although it depends on the performance of the used catalyst, the temperature control of the coolant so that the temperature difference in the fluid between the pipe 8a coolant and tubing 8b for release of fluid is in the range from 1 to 10°C, preferably from 2 to 6°C.

To minimize losses of the flow velocity of the fluid at the periphery, it is desirable to install the guide plate (not shown in the drawing) on the inner surfaces of the shell ring is Breznik channels 3a and 3b. As the guide plates are porous plate, the plate with the slits and the like, and the straightening of the stream is carried out by changing the area of the holes or the distance between the slits of the porous plate so that the coolant flows from the periphery at the same flow rate. The temperature in the annular channel (3a, preferably also 3b) can be controlled by selecting two or more of thermometer 15.

The number of guide walls, mounted in the housing 2 of the reactor, are virtually unlimited, but usually it is advisable to install three guide walls (two - type 6a and one type 6b). With these guides partitions the upward flow of coolant is changed so that it rotates in the transverse direction relative to the direction of the axis of the reaction tube and the fluid accumulates in the Central part of the reactor from its peripheral part, turns toward the peripheral part by changing its direction in the guide hole of the partition wall 6a, and then reaches the outer shell of the housing. The fluid accumulates in the Central part as a result of repeated changes of direction at the periphery of the guide walls 6b, rises to the hole of the guide walls 6a, turns to the periphery VD is l top tube 5a of the housing 2 of the reactor and recycle into the pump through the ring-shaped channel 3b.

According to this variant of the invention, thermometer 11 is inserted, at least one of the reaction tubes installed in the reactor, and transmits the signal from the reactor that allows you to record the temperature distribution in the catalyst bed in the direction of the axis of the reaction tube. In the reaction tube insert one, two or more thermometers and using one of these thermometers can measure from 5 to 20 temperature measurement points in the direction of the tube axis.

Selection guide walls in the invention does not limited provided that they have such a construction, in which they have a hole around the Central part of the reactor, and the partition includes an opening between the peripheral part and the outer shell of the housing and the fluid changes its direction at the respective openings, which prevents bypass flow of coolant and changes the rate of its flow, and illustrative examples of the shape of the guide walls include walls of the segment type disk partitions disk shape, etc.

Figure 2 shows the reactor type novotrubnogo heat exchanger, which is used in another typical embodiment, the method of gas-phase catalytic oxidation according to the invention. Figure 2 uses the item numbers of the elements in common with a number of the mi positions of the elements, described in the Chapter 1.

The reactor shown in figure 2, is a variant of the invention, in which the housing 2 of the reactor shown in figure 1, is divided intermediate tube plate 9, and the way in which you use this reactor is also included in the method according to the invention. In the divided spaces circulate various fluids, the temperature regulate. In figure 2 the direction of coolant flow is upward according to the arrow. The raw material gas can be fed either from the hole 4a, or from the hole 4b, but it is desirable that he was a counter-flow relative to the flow of the coolant. In this case, the hole 4b is a hole for the intake of raw materials and the raw material gas supplied from the hole 4b, sequentially subjected to the reaction in the reaction tubes of the reactor.

Fluids having different temperatures are in the upper and lower (A and B) zone of the reactor, separated by an intermediate tube plate 9, in accordance with Novotrubny reactor, shown in figure 2. Ways to fill each reaction tube is divided into three cases: 1) when the tube is uniformly filled with the same catalyst and the reaction is carried out by changing the temperature at the inlet for the feed gas and at the outlet of the reaction tube 2) to the da input part for inputting the raw gas are filled with catalyst, but for rapid cooling of the reaction product outlet portion not filled with catalyst, leaving the tube blank, or fill it with an inert substance with no reaction activity, and 3) when the input portion of the inlet feed gas and the output part of the reaction tube is filled by different catalysts, but for rapid cooling of the reaction product of the intermediate part is not filled with catalyst, leaving the tube blank, or fill it with an inert substance with no reaction activity.

For example, in Novotrubny reactor, shown in figure 2, propylene, propane or isobutylene is served in the form of a gas mixture with a molecular oxygen-containing gas holes 4b, is used as a raw material feed opening. First, at the first stage, for the implementation of the direct reaction stage (which corresponds to the area of A reaction tube, sometimes called "part of the direct reaction"), the propylene, propane or isobutylene used in the invention is converted into (meth)acrolein, and then, in the second stage, for reverse reaction stage (which corresponds to the area B of the reaction tube, sometimes referred to as the "site feedback"), oxidation (met)acrolein get (meth)acrylic acid. Plots of the reaction tube, intended for the implementation of the first and Vtorov the stage, fill different catalysts, and the reaction is carried out at optimum conditions, and handling them when appropriate different temperatures. It is desirable that an inert substance that does not apply to reactions, filled that part of the reaction tube, where the intermediate tubular bars 9 between stage direct part and parcel of the reverse stage of the reaction tube.

When the temperature difference between the parcel direct stage and a plot of the reverse stage exceeds 100°C, it is desirable to use two or more heat-shielding partition in position, approximately 10 cm above and 10 cm below the intermediate tube 9 to prevent heat transfer.

Although the direction of flow of the coolant inside the reactor vessel in figure 1 and 2 indicated by the arrow as the direction of the upward flow, in the invention it is also possible and reverse the direction of flow. In a downward direction of the circulating flow of coolant is necessary to avoid the phenomenon in which the gas, which may be at the upper end of the housing 2 of the reactor and circulating pump 7, for example nitrogen or a similar inert gas, is drawn into the flow of coolant. If the coolant flow is upward (figure 1), when the gas is drawn into the upper part of the circulating pump 7, the circus is acinom the pump occurs cavitation effect, causing, in the worst case, damage to the pump. When the coolant flow is downward, this effect also occurs in the upper part of the reactor, so that the upper part of the body formed a plot stagnant gas phase, and the upper portion of the reaction tube, it is impossible to cool the coolant.

To prevent stagnation important gas in the gas layer to replace the gas cooled by setting degassing line, and for this purpose to create a high pressure in the gas layer. For this purpose it is proposed to create in the body increased pressure of the fluid for which the pipeline 8a coolant and tubing 8b to release fluid set as much as possible, a high location. It is advisable to install the pipeline for release of fluid, at least on the upper side of the tube 5a.

When Novotrubny reactor, shown in figure 1, is used as novotrubnogo reactor for the oxidation of propylene, propane or isobutylene with molecular oxygen-containing gas and the process gas flow is downward, i.e., when the raw gas is fed through 4b, and product release through 4a, (meth)acrolein, a product of interest, has a high concentration and is heated by the heat of reaction in the hole 4a of the reactor, which is designed to release the PR, the product, or near it, so that the temperature of the process gas becomes higher. Therefore, in this case, it is advisable to install the heat exchanger in position 4a of the reactor or her, in accordance with figure 1, in consequence of which the process gas is substantially cooled, and (meth)acrolein is not subjected to the reaction of autoxidation.

In addition, when using Novotrubny reactor, shown in figure 2, and the process gas flow is downward, i.e., when the raw gas is fed through 4b, and product release through 4a, (meth)acrolein is a product of interest, has a high concentration and is heated by the heat of reaction at the intermediate tubular lattice 9, or near it, because it is a place of completion of the first stage reaction (zone a reaction tube), so that the temperature of the process gas becomes higher. When the catalyst fill only a part of the first stage (zone A reaction tube: 5a-6a-6b-6a-9), the reaction does not proceed actively on the part of the second stage of the reaction tubes 1b and 1c (zone B of the reaction tube: between 9 and 5b), so that the process gas is cooled by coolant flowing in the side channel of the body, and (meth)acrolein does not give rise to a reaction of autoxidation. In this case, the catalyst does not fill the area B of the reaction tubes 1b and 1c (between 9 and 5b), forming thus PU is the case tube, or it is filled solid with no reaction activity. Last, it is desirable to enhance the performance of heat transfer.

When different catalysts fill a part of the first stage reaction zone A reaction tube: 5a-6a-6b-6a-9) and part of the second stage (zone B of the reaction tube: 9-6a'-6b'-6a'-5b) novotrubnogo reactor, shown in figure 2, and (meth)acrolein is produced from propylene, propane or isobutylene in the first stage, and (meth)acrylic acid is obtained in the second stage, the temperature of the catalyst layer corresponding to the first stage, becomes higher than the temperature of the catalyst layer corresponding to the second stage. Illustrative, as the temperature becomes higher at the site of the completion of the second stage reaction (6a-9) and around the site of initiation of the second stage of the reaction (9-6a'), it is desirable that the reaction in this half were not in order, thus, the process gas was cooled by a coolant flowing in a side channel of the body, and (meth)acrolein are not subjected to the reaction of autoxidation. In this case, the plot is not filled with the catalyst, set around the intermediate tube 9 (around positions 6a-9-6a' of the reaction tubes 1b and 1c), forming thus an empty tube, or it is filled solid with no reaction activity. The village is ednie it is desirable to enhance the performance of heat transfer.

[The diameter of the reaction tube]

The inner diameter of the reaction tube novotrubnogo reactor is mainly from 10 to 50 mm, preferably from 20 to 30 mm, although it depends on the amount of heat of reaction and the size of the catalyst particles in the reaction tube. When the inner diameter of the reaction tube is very small, the amount of fill her catalyst decreases, resulting in increase the number of reaction tubes that are required to maintain the required amount of catalyst in the reactor, which, therefore, causes an increase in the cost of the reactor and, consequently, the deterioration of economic efficiency. On the other hand, when the inner diameter of the reaction tube is very large, it causes a deterioration in the efficiency of the heat sink.

[The coolant and the heat transfer coefficient]

Because the coolant is served in the annular zone, nitrate, a mixture of (sometimes referred to hereinafter as "nitrate"), organic liquid diphenyl ether or the like According to the invention as a specific desirable examples of the coolant consider the mixture of nitrates.

An example of the composition of the nitrate - 53 wt.% KNO₃(potassium nitrate), 40 wt.% NaNO₂(sodium nitrite) and 7 wt.% NaNO₃(sodium nitrate). When its composition is formed in various weight ratios, temperatures, the melting of the mixture changes. The acceptable range of compositions of nitrate depends on the temperature of its use.

It is desirable to use industrial products having a purity of 95 wt.% or more, for example KNO₃(potassium nitrate), NaNO₂(sodium nitrite) and NaNO₃(sodium nitrate). When the purity is less than 95 wt.%, this causes a tendency to manifest a large deviation of the melting temperature of the mixture from the set.

Heat of reaction in the reaction tube is given a stream of coolant. The coolant introduced into the reactor vessel from the annular channels intended for input of the heat carrier (for example, 3a of figure 1), has an area where it flows from the peripheral part to the Central part of the reactor, and the area in the Central part, where it changes its direction of flow is reversed and heat effect in these areas varies greatly. When the direction of the coolant flow and the direction of the axis of the reaction tube are at right angles to each other, the heat transfer coefficient ranges from 1000 to 2000 W/m²·°C. When the flow direction of the coolant and the direction of the axis of the reaction tube does not form a right angle with each other, the heat transfer coefficient depends on the flow velocity and flow direction, but is in the range from 100 to 300 W/m²·°C.

Because the cylinder is UNT heat transfer catalyst layer, inside the reaction tube depends on the flow rate of the raw gas and is about 100 W/m²·°C, stage, determining the flow rate of the heat carrier is phase heat transfer in the gas phase in the tube. When the direction of the coolant flow and the direction of the axis of the reaction tube are at right angles to each other, thermal resistance outside of the tube is about 1/10-1/20, which is the gas in the tube, thus, the effect of the flow rate of the coolant at the total thermal resistance is small. However, when the flow of fluid parallel to the axis of the reaction tube, the heat transfer coefficient inside and outside the reaction tube is almost the same, thus, the heat transfer coefficient when the heat sink is heavily dependent on the state of the liquid coolant. For example, when thermal resistance of the fluid outside the tube is 100 W/m²·°C, total heat transfer coefficient is half of it, and change half thermal resistance outside of the tube affects the full transfer coefficient.

[Catalyst]

Since the catalysts used in the production of (meth)acrolein or (meth)acrylic acid obtained by the reaction of gas-phase catalytic oxidation, should prisutstvie the VAT as those are used to direct the reaction of olefin to unsaturated aldehyde or unsaturated, and those that are used to reverse the reaction from the unsaturated aldehyde to unsaturated acids, and they can be applied for each of the reactions according to the invention.

Compounds represented by the following formula composition (I), can be explained by the example of the composite oxide catalyst on the basis of the Mo-Bi used in direct reaction stage.

The formula of structure (I): MO_aW_bBi_cFe_dA_eB_fC_gD_hE_iO_x

In the formula of part (I) Mo is molybdenum, W is tungsten, Bi is bismuth, Fe is iron, A is at least one element selected from Nickel and cobalt, B is at least one element selected from sodium, potassium, rubidium, cesium and thallium, C is at least one element selected from alkaline-earth metal, D is at least one element selected from phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic, boron and zinc, E is at least one element selected from silicon, aluminum, titanium and zirconium, and O is oxygen. The letters a, b, c, d, e, f, g, h, i and x, respectively, denote the atomic relations of Mo, W, Bi, Fe, A, B, C, D, E, and O, and when a is 12, b is from 0 to 10, p is from 0 to 10 (preferably, from 0.1 to 10, d is from 0 to 10 (preferably, from 0.1 to 10, e is 0 to 15, f is from 0 to 10 (preferably, from 0.001 to 10), g is from 0 to 10, h is 0 to 4, i is from 0 to 30, and x is a value that is determined by the oxidation state of each element.

Compounds represented by the following formula composition (II)can be explained by the example of the composite oxide catalyst based on Mo-V, used to reverse the reaction.

The formula of structure (II): Mo_aV_bW_cCu_dX_eY_fO_g

In the formula of structure (II) Mo is molybdenum, V is vanadium, W is tungsten, Cu is copper, X is at least one element selected from Mg, Ca, Sr and Ba, Y is at least one element selected from Ti, Zr, Ce, Cr, Mn, Fe, Co, Ni, Zn, Nb, Sn, Sb, Pb and Bi, and O is oxygen. The letters a, b, c, d, e, f and g, respectively, mean atomic relations Mo, V, W, Cu, X, Y and O, and when a is 12, b is from 0 to 14, p is from 0 to 12, d is from 0 to 6, e is 0 to 3, f is 0 to 3 and g is equal to the value, which is determined by the oxidation state of each element.

The above catalysts are produced, for example, using methods disclosed in JP-A-63-54942, JP-B-6-13096, JP-B-6-38918 etc.

The above catalysts can be catalysts manufactured by pressing, extrusion or pelletizing, or supported catalysts, in which component catalyst comprising a composite oxide supported on an inert carrier such as silicon carbide, aluminum oxide, dioxide CID is one, the titanium oxide or the like

The choice of the form of the catalyst is practically nothing limited, and its examples include spherical, columnar, cylindrical, star-shaped, ring-shaped, shapeless, etc.

[Thinner]

The above-mentioned catalyst can also be used by mixing with an inert substance used as a diluent.

The choice of inert matter, practically nothing is not limited, provided that it is a substance, which is stable under the conditions of the above reaction does not react with the raw material and the product and can represent, for example, aluminum oxide, silicon carbide, silica, zirconium oxide, titanium oxide, and other similar substances used as a catalyst carrier.

Moreover, the choice of its shape almost nothing limited, as in the case of the catalyst, and thus, it can be of any shape, for example, spherical, columnar, cylindrical, star-shaped, ring-shaped, the shape of a small coin, EcoObraz, amorphous, etc. the Size is based on diameter of the reaction tube and the pressure drop.

<the catalyst is Mixed with the diluent>

The amount of the inert substance used as a diluent, depends on the catalyst activity, representing the I interest may be obtained. For example, you can increase the used quantity of the inert substance filling layer located around the opening for the intake of raw materials or in the same area, where the catalytic activity is reduced in order to control the exothermic heat of the reaction tube. The amount of inert substances can also lower in the water layer, located around the outlet openings of the reaction gas or similar area where the catalytic activity is increased. Alternatively, the catalyst and the diluent can be mixed in a predetermined ratio and to fill it to the reaction tube in a single layer.

In the used method in the case of filling two layers as catalyst with a high proportion of particles of inert substances located in that part of the reaction tube, which is designed for the intake of raw gas, used particles of inert substances, the proportion of which is from 0.3 to 0.7, and to fill the outlet of the reaction tube is used catalyst with a low proportion of diluent or not containing such, with the proportion of inert substances from 0 to 0.5.

The number of layers of catalyst, created along the axis direction novotrubnogo reactor with fixed bed, practically unlimited, but it mainly is about the 1 to 10 layers. When the number of layers of the catalyst is very high, to fill the reactor with the catalyst requires a significant effort. The length of each catalyst layer can be defined based on the type of catalyst, amount of catalyst, reaction conditions, etc.

[Method of regulating the temperature of the heat carrier]

According to the invention the selection of the method of regulating the temperature of the heat carrier virtually no limits.

For example, according to the example system of reactor and heat exchanger, shown in figure 3, the coolant temperature can be adjusted by cooling using a heat exchanger 20 of figure 3 of part or all of the heat carrier, loaded with the upper end of the circulating pump 7 of the reactor through line 8b for the production of brine, followed by circulation of chilled coolant in the reactor by returning it to the reactor system through line 8a coolant. The number of the loaded carrier is brought to the desired volume using the control valve 21. According to another variant embodiment of the invention shown in figure 4, the carrier loaded through line 8b for release of the fluid installed at the lower end of the circulating pump 7 of the reactor may be recycled to the reactor system through line 8a for supplying warm the media, mounted at the upper end of the circulation pump 7. None of these options is carried out in accordance with the apparatus conditions, raw materials, etc.

When the coolant temperature becomes high due to the absorption of heat by the coolant temperature is mainly increased by the value from 1 to 10°S, preferably from 2 to 6°C, to prevent the formation of stretch overheating (the active site), from the viewpoint of protection of the catalyst.

The choice of the type of heat exchanger is virtually unfettered. Its illustrative examples include stationary tubular bars of the upright type, a stationary tubular lattice of horizontal, U-shaped tube, double tube, spiral tube, the tube in the form of angle etc.

Examples of materials, although they do not have special restrictions include carbon steel, stainless steel and other similar materials that you can choose, taking into account thermal resistance, corrosion resistance, cost effectiveness etc.

[Regulating valve installed on the device or piping for coolant]

Since the temperature difference is very small, as described above (generally from 1 to 10° (C)requires precise control of the valve which controls the amount of heated fluid supplied to heat obmennik. On the other hand, since the coolant consists of substances with high melting point, under the influence of the outgoing radiation or heat, it immediately hardens, so that the valve becomes unstable or defective.

According to the invention in the omental flap is not material based on graphite and the material on the basis of mica. When using material based on graphite nitrate penetrates the gland, which because of this becomes unworkable.

Also according to the invention it is desirable to use such a design of the shirt, which is heated sealing part of the valve. When performing this prevents the solidification of the fluid, and smooth operation of the valve is ensured for a longer period of time, which thus makes it possible to adjust accurately the corresponding small changes in temperature and flow rate.

In addition, in the actuator, use a device that has a high enough power. High enough power means driving force, which in the absence of fluid flow is set relations [sliding friction force between the valve body and an associated rod]/[maximum force drive start]equal to 0.2 or less. More preferably 0.15 or less. When the value is NII, larger 0,2, carry out the fine adjustment is not possible, because the valve is required to have a significantly higher driving force.

Also, if the valve before you begin it is necessary to conduct operational inspection (including inspection of how accurately it regulates 1%intervals) by issuing carrier (nitrate) after turning off the equipment (for example, when annual maintenance and repairs, and so on), always removing it after the equipment was cooled, and checking the equipment inside.

Specifically in the case of systems in which the system of coolant circulation and temperature control with only one valve for regulating the temperature of the coolant, defective operation of the temperature control becomes impossible, so that the strict observance of the above rules, maintenance and testing activities is very effective.

Next is described on the basis of figure 5 a typical implementation of the above-mentioned characteristics of the control valve related to the circulation of the coolant and the temperature control system equipment used in the method of gas-phase catalytic oxidation according to the invention.

Figure 5 is a structure the RNA circuit example of the control valve, used according to the invention in the system of coolant circulation and temperature control. Figure 5 as a control valve uses a spherical disc valve, but as for the type of control valve, it may be non-spherical disc valve presented on figure 5, for example, it may be spherical valve, ball valve, gate valve or double valve.

Figure 5 aluminum body of the valve is the main valve body, which can be flanged type (variant implementation presented on figure 5) or plug-in type without flange. In addition, as the material of the body, usually used carbon steel, stainless steel and so on, but this list is not limited, and the material can be selected, taking into consideration the heat resistance, corrosion resistance, cost effectiveness etc.

Using A2 (spherical disk) is the regulatory mechanism of differential fluid pressure by turning it about 90° inside the main valve body. In the case of the above-mentioned another type of control valve spherical disk A2 can be in the form of a disk, moving in a vertical direction against the fluid flow.

For remote control of regulated is the missing A3 valve (actuator) receives electric or gas (air, the nitrogen or the like) signal with a control panel located in the control room, and converts this signal into a driving force needed to start the valve. He may be a cylindrical type or diaphragm type. The driving force is converted by the actuator is transmitted to the spherical disk A2 stock A4, allowing, thus, to perform the functions of the valve. Depending on the type of valve stem A4 can either rotate against the direction of the axis, or slide in the direction of the axis. According to the invention A5 (gasket seal) inserted into the rod seal A4 and housing A1. As a material it is necessary to use material based on graphite, commonly used as a heat-resistant material, and the material on the basis of mica. In the event of a material based on graphite material undergoes corrosion caused by nitrate, which, thus, may cause sticking of piston rod stuffing part, but this is prevented by the use of materials based on mica. The material on the basis of mica used in the invention generally is an aluminosilicate containing an alkaline metal, in accordance with the chemical structure, including Muscovite, lepidolite, paragonite, vanadinite, sericite and similar Muscovite, biotite, phlogopite, lepidomelane, zinnwaldite and similar biotite, slawsonite, celadonite, etc. but cogdon used as an element of the device, in most cases, their identification is not required, as they may have similar characteristics, so they just named mica.

On the other hand, the space between the spherical disk A2 and the housing A1 sealed bond A6 (o-ring) with A7 (lock). To prevent improper operation caused by the accumulation of nitrate, A8 (steam jacket) is attached to the housing A1 and to the stuffing part. It is advisable to install a steam jacket inside of the shell, but it can take half shell, when attaching to the shell is difficult due to the structure of the valve.

In addition, taking into account the deformation caused by thermal expansion, uses the same material for making the body. High-pressure steam having a saturation temperature above the melting temperature of the coolant supplied from the A9 (inlet steam nozzle) in this steam jacket, and water for condensers extracted from A10 (steam injection nozzle).

<Examples>

For an illustrative description of the invention it is described in detail with reference to examples and comparative examples, although not limited to them.

Example 1

<Catalyst>

After dissolution 94 mass parts of paramolybdate antimony 400 mass parts of pure water when heated mass of 7.2 parts of nitrate trehu entogo iron, 25 mass parts of cobalt nitrate and 38 mass parts of Nickel nitrate were dissolved in 60 mass parts of pure water under heating. These solutions were mixed with sufficient mixing intensity.

Then 0,85 mass parts of borax and 0.36 mass parts of potassium nitrate were dissolved in 40 mass parts of pure water when heated and added to the above slurry. Then, thereto were added 64 mass parts of granulated silica and mixed by shaking. Then, thereto were added 58 mass parts of the basic carbonate of bismuth, pre-mixed with 0.8 wt.% Mg and mixed by shaking, and then this slurry was dried by heating, and maintained at 300°C for 1 hour in an atmosphere of air, the thus obtained solid substance was subjected to pelletizing at the molding machine to form tablets of 5 mm diameter and 4 mm thick, and then the tablet was subjected to calcination at 500°C for 4 hours to obtain a catalyst.

Thus obtained catalyst is a powder of a composite oxide catalyst on the basis of Mo-Bi having the formula composition Mo(12)Bi(5)Ni(3)Co(2)Fe(0,4)Na(0,2)Mg(0,4)B(0,2)K(0,1)Si(24)O(x) (x oxygen is the amount that is determined by the oxidation state of each metal).

In this example, used a lot of ruby reactor, similar to the reactor shown in figure 1.

The illustration presents Novotrubny reactor, comprising a reactor (4500 mm in internal diameter) and having 10000 reaction tube made of stainless steel, where each reaction tube has a length of 3.5 m and an internal diameter of 27 mm Reaction tube is not installed in the area of the Central round hole perforated disc-shaped guide walls 6a, with the area of the holes near the Central part of the reactor vessel. Guides partitions are mounted so that the perforated disc-shaped guide wall 6a, with the area of the holes near the Central part of the reactor, and a perforated disc-shaped guide wall 6b are located so that they have areas of holes located between the peripheral part and the housing of the reactor, forming a uniform spacing 6a-6b-6a, while the share of area of holes of each of the guide walls is 18%.

The mixture of molten salts of nitrates (nitrate) was used as a coolant and recycled by feeding from the bottom of the reactor and release of the upper part of the reactor.

Part of this fluid was released from one of the pipes 8b coolant cooled via a heat exchanger having to the construction, shown in figure 5, and then returned to another pipeline 8a coolant (cf. figure 3). The produced quantity of the fluid was adjusted by the regulating valve (21 of figure 3, details are shown in figure 5), which are provided to the piping system to supply the system 8b-exchanger-8a). The temperature of the coolant fed to the reactor was regulated by this valve and measured by a thermometer (15 of figure 1).

The control valve 21 is a valve in which the seal is used mica gasket (from commercially available mica), which, including the omentum, covered with steam jacket and positioned so that in the absence of fluid flow, it is important relations [sliding friction force between the valve body and an associated rod]/[maximum force drive start], equal to 0.2.

At the beginning of the work, check the working condition of the valve and how exactly it operates at 1%intervals.

Since the catalyst was filled in each reaction tube, the above-mentioned catalyst direct reaction stage was used after adjusting its catalytic activity carried out by mixing with silica beads having a diameter of 5 mm and not having catalytic activity, and filling out the entrance of the reaction tube so clicks the zoom, what degree of catalytic activity was 0.5, 0.7 and 1.

The raw gas was applied from the upper part of the reactor so that it formed a counter-flow with heat transfer fluid, while the raw material gas consisting of 9 mol%. propylene, and 1.9 mol%. molecular oxygen, 9 mol%. water and 80.1% of the mol. nitrogen was applied at a flow rate of 12300 standards. m³/h at a gauge pressure of 75 kPa (kilopascals). The temperature distribution in the reaction tube was measured by placing thermometer 10 measuring points located along the axis direction of the reaction tube.

After operation for 1 week by setting the temperature of the coolant at the inlet equal to 335°C, the first layer of the catalyst showed the highest maximum reaction temperature equal to 395°C, the conversion rate of propylene was 97%, and the total output acrolein and acrylic acid was 92%. As the reaction temperature used, the temperature of nitrate fed to the reactor. The temperature difference between the inlet and outlet of nitrate was 3°C.

Nitrate was applied to the heat exchanger through the regulating valve to adjust the temperature, cooled, and then returned to the reaction system from 8a.

Safe operation of the regulating valve to adjust the temperature continued for 1 year.

[Compare the sustained fashion example 1]

Operation according to the invention was carried out in the same manner as in example 1 using a control valve used in example 1 having the same shape and the mechanism of exploitation, however, as the material of the packing gland was used for the carbon in the graphite form, and in the absence of fluid flow, used the value of the ratio [sliding friction force between the valve body and an associated rod]/[maximum force drive start], changed to 0.4. 2 months after the start of operation creates operational failure, and the operation was stopped because of the difficulty in adjusting the temperature nitrate.

Example 2

Operation method according to the invention was carried out in the same manner as in example 1, but the valve was replaced, so that in the absence of fluid flow ratio [sliding friction force]/[maximum strength startup drive] was equal to 0.06. In the sealing material control valve used the same mica as in example 1.

Since the operation of this regulating valve is carried out very smoothly, the temperature control was carried out so neatly, so the valve was suitable for continuous operation for 1 year.

Since the invention has been described in detail and with reference to its specific options Khujand the exercise of, for specialists in the art it should be clear that it can be made various changes and modifications without departure from its nature and scope.

This application is based on patent application Japan, filed on may 19, 2004 (application for Japan patent No. 2004-148875), the entire contents of which are thereby incorporated by reference.

1. Method for the production of (meth)acrolein or (meth)acrylic acid through the implementation of the reaction of gas-phase catalytic oxidation of propane, propylene, isobutylene or (meth)acrolein oxygen-containing gas using an inorganic salt as a coolant to control the temperature of the reaction, characterized in that the material of the stuffing box packing which seals the housing of the control valve mounted on the pipe coolant and regulating the feed rate and the circulation of the coolant and regulating the rotational degree of mobility to the axis of rotation, which is associated with the above case so that they can slide relative to each other, is a material based on mica.

2. Method for the production of (meth)acrolein or (meth)acrylic acid according to claim 1, characterized in that the sealing part of the regulating valve has a construction in which the heat provided by Adelina shirt.

3. Method for the production of (meth)acrolein or (meth)acrylic acid according to claim 1 or 2, characterized in that the drive of the regulating valve in the absence of fluid flow has a value of the ratio (sliding friction force between the valve body and an associated rod)/(max power drive start)equal to 0.2 or less.

4. Method for the production of (meth)acrolein or (meth)acrylic acid according to claim 1, characterized in that the above-mentioned inorganic salt is a nitrate mixture consisting of 53 wt.% KNO₃(potassium nitrate), 40 wt.% NaNO₂(sodium nitrite) and 7 wt.% NaNO₃(sodium nitrate).

5. Device for the production of (meth)acrolein or (meth)acrylic acid, characterized in that it is used in the production method according to any one of claims 1 to 4.