Aggregate for (met)acrylic acid obtainment and method of (met)acrylic acid obtainment

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

 

The technical field to which the invention relates

The present invention relates to a device for producing (meth)acrylic acid and to a method for producing (meth)acrylic acid by gas-phase catalytic oxidation of propane, propylene, isobutylene or (meth)acrolein. In particular, the present invention relates to a device and a method for producing (meth)acrylic acid, to prevent performance degradation of the process of obtaining (meth)acrylic acid due to clogging of the heat exchanger placed between the reactor and the absorption tower, after the extraction of (meth)acrylic acid from the reaction gas mixture, which is supplied from the reactor in the absorption tower.

The level of technology

In the method of obtaining a (meth)acrylic acid, as a rule, we use a method that includes: obtaining a (meth)acrylic acid by gas-phase catalytic oxidation of propane, propylene, isobutylene or (meth)acrolein; supply of the reaction gas mixture containing the obtained (meth)acrylic acid in the absorption tower in order to introduce the reaction gas mixture in contact with the absorbing liquid, such as water; and removing the (meth)acrylic acid from the reaction gas mixture in the form of a solution (meth)acrylic acid.

This method of production on the replies: reactor, containing a catalyst for the reaction of gas-phase catalytic oxidation, which introduced the original gaseous substances; and the absorption tower. The temperature of the reaction gas mixture withdrawn from the reactor, the specified stage is usually from 250 to 350°C. At the same time, absorption tower for (meth)acrylic acid operates at a temperature of from about 50 to 150°C. Therefore, in the method of obtaining a (meth)acrylic acid is usually used the installation, in which the supply line of the gas mixture in an absorption tower contains a heat exchanger designed to cool the reaction gas mixture to extract heat energy from the reaction gas mixture, the efficiency of absorption of (meth)acrylic acid in the absorption tower and so on (see for example, JP 50-095217 A, JP 46-040609 B and JP 08-176062 A).

The reaction gas mixture in this case contains substances such as phthalic acid and maleic acid, and these compounds in the implementation of continuous process stick to the heat exchanger, which leads to clogging of the heat exchanger. When the heat exchanger is sealed, the pressure inside the reactor is increased, making it difficult to proceed normally. In this case, the operation can be continued with reduced performance of the process of obtaining meth)acrylic acid or the process must be stopped to clean the heat exchanger. Specified clogging of the heat exchanger creates difficulties for stable operation of the production plant for producing (meth)acrylic acid and reduces the performance of the process of obtaining (meth)acrylic acid.

An example of a known method of removing a substance that stuck to the heat exchanger, includes installation, comprising: a zone of deposition of the high-boiling impurities, which is placed in the pipeline for the transfer of the reaction gas mixture, to remove high boiling impurities from the reaction gas mixture; and another zone of deposition of the high-boiling impurities, is placed in the pipeline for the transfer of the reaction gas mixture, which can be cleaned in the chamber adjacent to the pipeline for transfer of the reaction gas mixture, and thereby to remove high boiling impurities from the reaction gas mixture through the zone of deposition of the high-boiling impurities (see, for example, JP 08-134012 A).

Examples of the known methods of preventing the formation of sludge in the heat exchanger include a method comprising: maintaining the temperature of the cooling surface of the heat exchanger at a level equal to or higher than the boiling point of maleic anhydride; and maintaining an average speed of flow of the reaction gas mixture at the specified level or above target levels (see, for example, JP 50-126605 A).

The man is e, there are no messages on adhesion of sludge to the heat exchanger in the plant, provided with a heat exchanger designed to cool the reaction gas mixture that is fed into the absorption tower. Thus, in the case where it is possible adhesion of the specified sediment, for a stable process, it is necessary to take additional measures.

In addition, methods of sludge removal from the heat exchanger or ways of preventing the adhesion of sludge to the heat exchanger may require the creation of large-scale plant for producing (meth)acrylic acid or the development of complex processes or methods may lead to limited cooling of the reaction gas mixture in the heat exchanger. There is no indication on how to prevent clogging of the heat exchanger, so if possible adhesion of sludge to the heat exchanger, to implement a stable operation of the installation, you must consider additional measures.

Description of the invention

Thus, an object of the present invention is a method, which eliminates the disadvantages of known methods, i.e. a method that allows you to remove heat from the reaction gas mixture, when the (meth)acrylic acid contained in the reaction gas mixture which is withdrawn from the reactor, served in the absolute is blennow tower, where it is recovered in the form of a solution of (meth)acrylic acid and provides a stable and continuous process even in the case where the heat exchanger is blocked.

According to the present invention when removing acrylic acid or methacrylic acid (hereinafter referred to acrylic acid and methacrylic acid each or both denote the General term “(meth)acrylic acid”) in the form of a solution (meth)acrylic acid by cooling the reaction gas mixture which is withdrawn from the reactor through a heat exchanger and feeding the cooled reaction gas mixture in an absorption tower, a heat exchanger designed to cool the reaction gas mixture supply bypass pipe that connects the inlet and outlet of the heat exchanger, and the pressure inside the reactor is maintained at a given level in order to prevent the degradation of the process of obtaining (meth)acrylic acid due to the decrease of the feed rate to the reactor gas flow containing source materials, by gradually opening valve installed in the bypass pipe when the pressure in the reactor increases due to clogging of the heat exchanger.

Thus, the present invention proposes a device for producing (meth)acrylic acid, which comprises: a reactor for the production of (meth)and iloveu acid by the reaction of gas-phase catalytic oxidation of one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein, from a gas mixture of original substances, containing one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein and oxygen; a heat exchanger designed to cool the reaction gas mixture containing the obtained (meth)acrylic acid; and an absorption tower, which is designed to contact the absorbing liquid, for the purpose of absorption of (meth)acrylic acid, and the reaction gas mixture so that the (meth)acrylic acid from the reaction gas mixture is absorbed by the absorbing liquid, and the device for producing (meth)acrylic acid further includes a loop pipe, intended to connect the reactor and the absorption tower without the use of an intermediate heat exchanger; and a device that regulates the flow rate, designed to regulate the speed of flow of the reaction gas mixture which flows through the bypass pipe.

In addition, the present invention proposes a method of obtaining a (meth)acrylic acid by extracting the (meth)acrylic acid, absorbed in the absorbing liquid, which comprises the following stages: formation of (meth)acrylic acid in the reactor by reaction gasof the EIT catalytic oxidation of one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein, from a gas mixture of original substances, containing one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein and oxygen; the distribution of the reaction gas mixture formed of (meth)acrylic acid, in a heat exchanger designed to cool the reaction gas mixture in an absorption tower, which is intended for contacting the reaction gas mixture with an absorbing liquid, for the purpose of absorption of (meth)acrylic acid; cooling the reaction gas the mixture entering the heat exchanger through the heat exchanger; and the contacts inside the absorption tower of the reaction gas mixture is cooled in the heat exchanger and the reaction gas mixture supplied to the absorption tower at the stage of distribution, so that (meth)acrylic acid contained in the reaction gas mixture is absorbed by the absorbing liquid, while the reaction gas mixture is distributed with the speed of the feed gas mixture starting materials in the reactor at the stage of distribution.

Brief description of drawings

Figure 1 shows schematic diagram showing the structure of the production installation in accordance with the var is the ant constructs of the present invention.

Figure 2 presents a chart showing the design novotrubnogo heat of the reactor, which is used in the method of gas-phase catalytic oxidation according to the present invention.

Figure 3 presents a chart showing the design novotrubnogo heat of the reactor, which is used in the method of gas-phase catalytic oxidation according to the present invention.

The best option is the implementation of the present invention

In industry (meth)acrolein or (meth)acrylic acid is usually produced by oxidation of propane, propylene, isobutylene and/or acrolein molecular oxygen in the presence of a solid catalyst, i.e. by so-called gas-phase catalytic oxidation.

Hereinafter in this description, examples of the method of obtaining a (meth)acrylic acid are explained on the example of acrylic acid. These examples include the following examples(1) - (3).

(1) the Method comprises: a step for acrylic acid by gas-phase catalytic oxidation of propane, propylene and/or acrolein; selection stage, where collecting the acrylic acid in the aqueous solution of acrylic acid by contacting a gas containing acrylic acid, formed at the stage of obtaining acrylic key is lots with water as the absorbing liquid; phase extraction, in which acrylic acid is extracted from the aqueous solution of acrylic acid using the appropriate extracting solvent; phase separation of acrylic acid and extracting solvent; purification stage, which carried out the purification of the obtained acrylic acid; phase extraction of acrylic acid by decomposition of high boiling liquid containing the Michael adducts of acrylic acid and a polymerization inhibitor, which are formed on the above-mentioned stages, and the stage of filing of acrylic acid at any stage after stage of selection.

(2) the Method comprises: a step for acrylic acid by gas-phase catalytic oxidation of propane, propylene and/or acrolein; selection stage, where collecting the acrylic acid in the aqueous solution of acrylic acid by contacting a gas containing acrylic acid, formed at the stage of obtaining acrylic acid, with water as the absorbing liquid; phase azeotropic separation by extraction of the crude acrylic acid from the bottom of the column for azeotropic separation by distillation of the aqueous solution of acrylic acid in the presence of an azeotropic solvent; phase separation of acetic acid by removal of acetic acid ispoluemogo crude acrylic acid; purification stage, which carried out the purification of the obtained acrylic acid; phase extraction of acrylic acid by decomposition of high boiling liquid containing the Michael adducts of acrylic acid and a polymerization inhibitor, which are formed on the above-mentioned stages, and the stage of filing of acrylic acid at any stage after stage of selection.

(3) the Method comprises: a step for acrylic acid by gas-phase catalytic oxidation of propane, propylene and/or acrolein; stage selection/separation, which carry out selection of acrylic acid in the form of an organic solution of acrylic acid by contacting a gas containing acrylic acid, formed at the stage of obtaining acrylic acid from the organic solvent with simultaneous removal of water, acetic acid, etc.; phase separation, which carried out the selection of acrylic acid from a solution of acrylic acid in an organic solvent; the stage of extraction of acrylic acid by decomposition of high boiling liquid containing the Michael adducts of acrylic acid and inhibitor of polymerization, which are formed on the above-mentioned stages; stage filing of acrylic acid at any stage after the screening stage; and a stage of partial or complete removal of organic solvent.

In this way parents just paid constraints can be applied to any method of obtaining a (meth)acrylic acid by the reaction of gas-phase catalytic oxidation.

A method of obtaining a (meth)acrylic acid of the present invention involves the following stages: education (meth)acrylic acid in the reactor by the reaction of gas-phase catalytic oxidation of one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein, from a gas mixture of original substances, containing one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein and oxygen; the distribution of the reaction gas mixture formed of (meth)acrylic acid, in a heat exchanger designed to cool the reaction gas mixture and in the absorption tower, designed to probe the reaction gas mixture with an absorbing liquid, for the purpose of absorption of (meth)acrylic acid; cooling the reaction gas mixture fed to the heat exchanger, using the heat exchanger; and the contacts inside the absorption tower of the reaction gas mixture is cooled in the heat exchanger and the reaction gas mixture supplied to the absorption tower at the stage of distribution, so that (meth)acrylic acid contained in the reaction gas mixture is absorbed by the absorbing liquid.

According to the present invention, the stage of education (meth)acrylic acid, cooling reacts the availability of the gas mixture using a heat exchanger and absorption of (meth)acrylic acid absorbing liquid can be conducted using known devices, such as the well known setting or known by the node.

In the present invention the stage of distribution of the reaction gas mixture includes the distribution of the reaction gas mixture obtained at the stage of formation of (meth)acrylic acid in the heat exchanger and in the absorption tower. The distribution is carried out with the speed of the feed gas mixture starting materials in the reactor in order to prevent the decrease in the rate of supply of the gas mixture starting materials in the reactor.

In the case where a gas mixture of original substances fed into the reactor using a pressure differential between the pressure inside the reactor and the pressure of a gas mixture of original substances, the phase distribution is carried out taking into account the pressure of the gas mixture of original substances, which serves at the reactor inlet in order to prevent the decrease in the rate of supply of the gas mixture starting materials in the reactor, caused by the fact that the increase in pressure inside the reactor leads to the fact that it becomes identical to the pressure of the gas mixture of original substances, which are served in the reactor.

At the stage of distribution of the ratio of the reaction gas mixture is directed into the heat exchanger and absorption column, is not specifically limited, provided that there is the required rate of supply of the gas mixture starting materials in the reactor. For example, the reaction gas, see the camping, formed in the reactor can be completely sent to the heat exchanger.

At the stage of distribution of the reaction gas mixture mainly distributed in such a way as to obtain a practically constant speed feed gas mixture starting materials in the reactor in order to ensure stable production of (meth)acrylic acid. The expression “almost constant” in this case means that the feed rate of the gas mixture starting materials in the reactor is in the range that does not affect the production of (meth)acrylic acid. This range varies depending on the size of the installation and the like, however, it is approximately ±5% vol. feed rate of the gas mixture starting materials in the reactor at the initial stage of the production installation.

In the case where a gas mixture of original substances fed into the reactor using a pressure difference between the pressure inside the reactor and the pressure of a gas mixture of original substances, the reaction gas mixture mainly distributed in such a way as to ensure that at the stage of distribution is almost constant pressure of the gas mixture of the original substances at the entrance to the reactor in order to ensure stable production of (meth)acrylic acid. The expression “almost constant” means in this case, h is about the pressure must fall within the range, depending on the above numerical value of the velocity of the feed gas mixture of original substances, and is approximately ±4 kPa relative to the pressure of the gas mixture of original substances at the entrance to the reactor at the initial stage of the production installation.

Stage distribution can be performed with the use of the bypass pipe, designed to guide the reaction gas mixture to bypass the heat exchanger, and a device for regulating the speed of flow of the reaction gas mixture inside the bypass pipe, such as a valve. The flow velocity of the reaction gas mixture inside the bypass pipe can be adjusted manually, but, preferably, it is regulate by means of an automatic valve, functioning in concert with a flow meter, which determines the speed of the feed gas mixture starting materials in the reactor, or with pressure gauge, which determines the pressure of the gas mixture of the original substances at the entrance to the reactor.

A method of obtaining a (meth)acrylic acid of the present invention can conveniently be applied to obtain the(meth)acrylic acid of the present invention, which is described below.

Figure 1 shows an example of a plant for producing (meth)acrylic acid used in the present invention. Production plant includes the: reactor 1; the heat exchanger 20, which is designed for cooling the reaction product obtained in the reactor 1; absorption tower 30 intended for absorption into the absorbing fluid of the specified component from the reaction product is cooled in the heat exchanger 20; loop pipe 40, intended to connect the tubing from the heat exchanger 20 to the reactor 1, and the tubing from the heat exchanger 20 to the absorption tower 30; and automatic valve 50 that is designed to regulate the flow of the reaction product, which flows through the bypass pipe 40. Automatic valve 50 is opened or locked depending on the magnitude of the pressure, which registers the pressure gauge 60, designed to determine the pressure of the gas mixture of the original substances from the inlet to the reactor 1, through which a gas mixture of original substances into the reactor 1. The production plant is equipped with optional not specified on the drawing, such as a distillation column and the decomposition reactor column, which is used in subsequent stages of the process.

The reactor 1 is a device for the formation of (meth)acrylic acid by the reaction of gas-phase catalytic oxidation of one or two or more source compounds comprising propane, propylene, isobutylene (meth)acrolein, from the gas mixture of original substances, containing one, or two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein and oxygen.

The present invention includes a method of obtaining acrylic acid by gas-phase oxidation of propylene and/or acrolein using molecular oxygen. Typical examples of commercial methods for producing acrolein and acrylic acid by gas-phase catalytic oxidation include single-stage system, recycling the unreacted propylene and the recirculated exhaust gases, which are considered in this description. The system of carrying out the reaction according to the present invention is not limited, provided that it allows to obtain a (meth)acrylic acid by the reaction of gas-phase catalytic oxidation using three of the above systems.

(1) One-step system

One-step system includes: mixing and feeding of propylene, air and steam for the implementation of the primary reaction; the conversion of the mixture mainly acrolein and acrylic acid; and the flow of exhaust gas to implement a secondary reaction without isolating the product from the flue gas. At this stage a common way for secondary reactions, in addition to on the ACI exhaust gas, also includes the supply of air and water vapor required for secondary reactions.

(2) recycling unreacted propylene

The system of recycling unreacted propylene, intended for recycling part of the unreacted propylene, includes: feeding the reaction gas mixture containing acrylic acid, which is obtained by the implementation of secondary reactions in the collection, designed to collect acrylic acid; collecting the acrylic acid in the aqueous solution; and returning part of the waste gas mixture containing unreacted propylene from the collector to the primary reaction.

(3) the System of recirculation of exhaust gases

The recirculated exhaust gases includes: the direction of the gaseous reaction products containing acrylic acid obtained by carrying out the secondary reactions in the collection, designed to collect acrylic acid; collecting the acrylic acid in aqueous solution; the burning of waste gases removed from the collection; the conversion of unreacted propylene and the like contained in the waste gas, mainly carbon dioxide and water; and returning the parts of the received exhaust gas to the primary reaction.

The reactor 1 is not specifically limited, provided that it represents the mouth of eusto, which allows to carry out the reaction in the above reaction system. The example of the reactor 1 includes Novotrubny reactor with a fixed catalyst bed. The reaction of gas-phase catalytic oxidation using novotrubnogo reactor with a fixed catalyst bed is a technique that is widely used to obtain (meth)acrolein or (meth)acrylic acid from propane, propylene or isobutylene in the presence of a mixed oxide catalyst using molecular oxygen or gas containing molecular oxygen.

In the present invention is applied Novotrubny reactor with a fixed catalyst bed, which is usually used in industry without any restrictions. Reactors of other types include plate reactor with a fixed catalyst bed and the reactor with a fluidized bed of catalyst, which can also be used as a reactor according to the present invention.

Next, a specific type of reactor 1 is described with reference to figure 2 and 3.

As shown in figure 2, the reactor 1 (hereinafter denoted as “Novotrubny reactor”), for example, includes: a housing 2; the holes 4A and 4b, available at both ends of the body 2 and serving as a loading opening through which gas serves a mixture of original substances, or open the I for unloading product, through which divert the reaction gas mixture containing the product; two tubular lattice 5A and 5b, which divide the interior space of the reactor 2 in the transverse direction; multiple reactor tubes 1b and 1C, which pass through the tubular lattice 5A and 5b and attached thereto; an annular tube 3A and 3b, intended for circulation of the coolant in the inner space of the housing 2, formed by two tubular bars and the outer casing of the housing 2; and perforated baffles 6a and 6b, which are alternately arranged in the longitudinal direction of the housing 2 in the space of the housing 2, formed by two tubular bars.

The reactor tube 1b and 1C are filled with catalyst or a similar substance. In addition, in each reactor tube 1b and 1C put thermometer 11. The catalyst or similar substance, which fills the reactor tube 1b and 1C describe later.

The annular tube 3A and 3b is provided with: a circulating pump 7, intended to circulate the coolant between the circular pipes 3A and 3b and the housing 2; line coolant 8A, intended for feeding fluid into the annular tube 3A and 3b; line drain coolant 8b intended to exhaust the coolant from the annular tubes 3A and 3b; and several thermometers 14 and 15, record the temperature Teflon is sites.

Each of the perforated baffles 6a and 6b is positioned so that it extends in the transverse direction inside the housing 2 and is fixed on the reactor tubes 1b and 1C. Perforated baffle 6a, for example, is a perforated wall of a toroidal shape, which extends from the inner peripheral wall of the casing 2 to the Central part of the housing 2, thereby forming an open area near the Central part of the housing 2. Perforated baffle 6b, for example, is a perforated wall of cylindrical shape, which extends from the Central part to the inner peripheral wall of the reactor 2, thereby forming an open area between the inner peripheral wall of the housing 2 and the edge of the perforated baffle 6b.

The shape and placement of each of the perforated baffles 6a and 6b are selected so that the projection of all of perforated partitions fills the cross section of the housing 2, when all of a perforated partition mounted in the housing 2, are projected on the cross section of the housing 2, in order to prevent the formation of hot spots (overheated parts) in the reactor tubes 1b and 1C.

In the reactor 1 shown in figure 2, the direction of flow used in the process gas (a gas mixture of original substances, the reaction gas mixture or both the x mixes together) is not specifically limited, provided that the flow directions are used in the process gas and the carrier opposite. In figure 2 the direction of flow of the fluid inside the housing 2 as indicated by arrows upward flow and, thus, the designation 4b indicates a hole for the filing of the original substances. A gas mixture of original substances, which are served through the hole for the filing of the original substances 4b, then reacts in the reactor tubes 1b and 1C of the reactor 1.

The fluid under pressure created by the circulating pump 7, rises up inside the housing 2 of an annular tube 3A, while it absorbs the heat generated in the reactor tubes 1b and 1C in the process of reaction of gas-phase catalytic oxidation. The flow direction of the coolant supplied into the housing 2, is changing a lot alternately installed perforated baffles 6A having an open area near the Central part of the housing 2, and a perforated baffle 6b, forming an open area near the inner peripheral wall of the reactor 2. Then, the coolant is returned to the circulation pump 7 through the annular tube 3b.

Part of the coolant that absorbs emitted during the reaction heat from exhaust coolant 8b attached to the upper part of the circulating pump 7, is cooled in the exchanger is Annika (not shown), again introduced into the annular tube 3A of the supply line fluid 8A and comes back into the case 2. The temperature of the coolant regulate by controlling the temperature or flow rate of the return fluid, which is injected through the supply line fluid 8A, based on the temperature, which, for example, is determined with the aid of thermometer 14.

The temperature regulating so that the difference in temperature of the coolant in the supply line of the fluid 8A and in-line exhaust fluid 8b was in the range from 1 to 10°C, preferably from 2 to 6°C, although it depends on the efficiency of the catalyst.

In the wall of the casing of each of the circular tubes 3A and 3b, preferably, is a plate that regulates the flow rate (not shown), to minimize the difference in the speed of flow of the coolant that passes through the cross-section of the tube, and including part of the plate that regulates the flow rate. As the plate that regulates the flow rate, use of a porous plate or a plate provided with slots, and an exposed surface of the porous plate or the intervals between the slits is changed so that the flow rate of coolant inside the case 2 was the same at any point of the cross section of the tube. The temperature inside the annular tube (3A, preferably, the e and 3b) can be controlled using several thermometers 15.

The number of perforated baffles 6 installed inside the housing 2, is not specifically limited, however, usually preferably set three perforated deflector (2 perforated baffle type 6A and 1 perforated deflector type 6b). Perforated baffles 6 prevent the formation of a simple upward flow of the coolant, changing the flow of the heat carrier in a lateral direction relative to the axial direction of the reactor tubes. The coolant is directed from the peripheral wall portion in the Central part of the housing 2, changes its direction in the open area of the perforated baffle 6A, rises upwards in the direction of the peripheral wall part of the housing 2 and reaches the peripheral wall of the housing 2.

The coolant again changes its direction in the peripheral wall under the action of the perforated baffle 6b is directed to the Central part of the housing 2, it is understood up through the open area of the perforated baffle 6A, flows through the tubular lattice 5A toward the peripheral wall of the housing 2 and is returned to the circulation pump through an annular tube 3b.

thermometer 11 is placed in the reactor tube 1b and 1C, are installed inside the reactor 1, and they transmit signals are transmitted outside of the reactor 1, and those with the most recorded temperature distribution in the catalyst layers in the axial direction of the reactor 1. In the reactor tubes 1 install multiple thermometers, and one thermometer measures temperatures in 5-20 points in the reactor tubes 1b and 1C in the axial direction.

As the reactor 1 is used, for example, the reactor shown in figure 3. Novotrubny reactor, shown in figure 3, has the same structure as Novotrubny the reactor shown in figure 2, except that the reactor is equipped with: an intermediate tubular wall 9, intended for additional separation space inside the housing 2, which is already divided tubular bars 5A and 5b; perforated baffles 6A and 6b as in space, the tubular bars 5A and the intermediate tubular wall 9 and in space, the intermediate tubular wall 9 and the tubular bars 5b; and annular tubes 3A and 3b, intended for the circulation of the coolant as in space, the tubular bars 5A and the intermediate tubular wall 9 and in space, the intermediate tubular wall 9 and the tubular bars 5b.

In spaces separated by an intermediate tubular wall 9 inside the housing 2, support different temperature by supplying different fluids. A gas mixture of original substances can either be supplied h is cut the hole 4A, either through the opening 4b. Figure 3 flow direction of the coolant inside the housing 2 as indicated by the arrows upward flow and, thus, the designation 4b indicates a hole for the filing of the original substances, while reacting gas mixture flows countercurrent relative to the coolant flow. The original substance, which serves through the hole for the filing of the original substances 4b, then reacts in the reactor tubes 1b and 1C of the reactor 1.

Novotrubny reactor, shown in figure 3, may include a coolant, the temperature of which is different in space, the tubular bars 5A and the intermediate tubular wall 9 (area And figure 3), and in space, the intermediate tubular wall 9 and the tubular bars 5b (area In figure 3). This difference in the temperature zones can be effectively used depending on the requirements of filling of the reactor tubes with the catalyst, etc.

Examples of this situation include: 1) the case when each of the reactor tubes completely filled with the same catalyst, and the temperature of the gas mixture of the starting substances for the purposes of carrying out the reaction is changed to the inlet and outlet of the reactor tube; 2) the case when the portion of the tube into which is introduced a gas mixture of original substances, filled with a catalyst, and that frequent the tube, from which divert the reaction gas mixture does not contain catalyst, i.e. is empty or filled with an inert substance that does not have reactivity with the purpose of rapid cooling of the reaction product; and 3) the case when the input and output parts are filled in with different catalysts, and the interval between them has no catalyst, i.e. is empty or filled with an inert substance that does not have reactivity with the purpose of rapid cooling of the reaction product.

For example, a gas mixture containing propylene, propane or isobutylene, and a gas containing molecular oxygen, is introduced into Novotrubny reactor, shown in figure 3,through the opening for the filing of the original substances 4b. First gas mixture is converted to (meth)acrolein in the first stage (area And the reactor tubes in the flow of the primary reaction, and then (meth)acrolein is oxidized in the second stage (the area In the reactor tubes) the result of the occurrence of secondary reactions and thus get a (meth)acrylic acid.

Part of the reactor tubes, which participates in the implementation of the first stage reaction (hereinafter describe it can also be referred to as “portion for holding the first stage”), and part of the reactor tubes, which participates in the implementation of the second stage of the reaction (the op is Saniya it can also be referred to as “portion for holding the second stage”), is filled with different catalysts and in them, with the goal of creating the optimal reaction conditions, support different temperature. An inert substance that does not participate in the reaction, mainly placed between the portion for holding the first stage and a portion for holding the second stage of the reactor tube (the part that is located in an intermediate tubular wall 9 and near it).

On each of 2 and 3, the flow direction of the coolant inside the housing 2 is shown as a bottom-up flow. However, the present invention can be applied in the case when the flow direction is opposite. With regard to the circulation of the coolant, the coolant circulates mainly in such a way as to prevent the capture of gas coolant, in particular, the seizure of inert gas, such as nitrogen, which is present in the upper parts of the housing 2 and the circulating pump 7, to ensure stable production of (meth)acrylic acid.

Line to drain coolant 8b preferably is located at least above the tubular bars 5A, in order to increase the pressure inside the housing 2. This construction prevents the stagnation of gas in the housing 2 or in the annular tubes 3A and 3b and to prevent cavitation within the circulation pump 7. In the case when the top cha the tee body 2 is formed a stagnant portion of the gas, the upper part of the reactor tubes, trapped in the stagnant zone of the gas may be cooled by the coolant, however, such construction allows to eliminate inefficient temperature control fluid.

In novotrubnom reactor oxidation of propylene, propane or isobutylene using a gas containing molecular oxygen, using novotrubnogo reactor shown in figure 2, in the case where the stream used in the process gas is downward, i.e. in the case when the gas mixture of original substances are served through the hole 4b, and the product is brought out through the hole 4A, the target product, (meth)acrolein, has a high concentration and hot due to the emitted during the reaction heat. Thus, the temperature used in the process gas may also increase near the hole 4A through which the discharged product.

In addition, novotrubnom reactor using novotrubnogo reactor, shown in figure 3, in the case where the stream used in the process gas is downward, i.e. in the case when the gas mixture of original substances are served through the hole 4b, and the product is brought out through the hole 4A, the target product, (meth)acrolein, has a high concentration and hot due to the emitted during the reaction heat, and thus, the temperature used in which the process gas may also increase near the intermediate tubular walls 9, which is located at the end of the course of the first phase (area And reactor tubes).

In the case when the catalyst is filled only with the purpose of the first phase region And the reactor tubes: 5A-6A-6b-6A-9), the reaction is suppressed in the second part of the reactor tubes 1b and 1C (the area In the reactor tubes: between 9 and 5b), and used in the process gas is cooled by the coolant, which flows through the area In the inside of the housing 2 in order to prevent the reaction of oxidation (meth)acrolein. In this case, the region In the reactor tubes 1b and 1C (between 9 and 5b) is not filled with catalyst, i.e. is empty or filled with a solid substance which has no reactivity. The second option is preferred from the viewpoint of improvement of the heat.

In addition, in the case when conducting the filling tubes of different catalysts for the first phase (area And reactor tubes: 5A-6A-6b-6A-9) and for the second phase (the area In the reactor tubes: 9-6A'-6b'-6A'-5b) novotrubnogo reactor, shown in figure 3, which is used to obtain a (meth)acrolein of propylene, propane or isobutylene in the first phase of the process and to obtain a (meth)acrylic acid in the second phase of the process, the temperature of the catalyst layer for the first phase the process can be higher compared to the temperature is th layer of the catalyst for the second phase. In particular, the first phase (6A-9) near the end point of the reaction and the second phase (9-6A') near the starting point of the reaction have a higher temperature.

Thus, preferably, the reaction is not carried out in these parts and used in the process gas is cooled by the coolant, which flows in the housing 2 near the intermediate tubular partition wall 9 in order to prevent the reaction of oxidation (meth)acrolein. In this case, near the intermediate tubular walls 9 are the part not filled with catalyst (parts inside 6A-9 6A' of the reactor tubes 1b and 1C), which are empty or filled with a solid substance which has no reactivity. The second option is preferred from the viewpoint of improvement of the heat.

Examples of the catalyst used for the reaction of gas-phase catalytic oxidation, with the purpose of obtaining a (meth)acrylic acid or (meth)acrolein include: catalyst, which is used for the primary reaction of obtaining unsaturated aldehyde or unsaturated acids from olefins; and the catalyst that is used for secondary reactions obtain unsaturated acids from unsaturated aldehyde. In the present invention can be applied to any of these catalysts.

In response gasof the importance of catalytic oxidation in the initial reaction (reaction conversion of the olefin to an unsaturated aldehyde or an unsaturated acid), with the aim of obtaining mainly acrolein, may be used a catalyst based on a mixed oxide of Mo-Bi. Examples of the catalyst based on a mixed oxide of Mo-Bi include the compound represented by the General formula (I):

MoaWbBicFedAeBfCgDhEiOx(I)

(where Mo is molybdenum; W denotes tungsten; Bi means bismuth; Fe denotes iron; And means, at least one element selected from Nickel and cobalt; means, at least one element selected from the group comprising sodium, potassium, rubidium, cesium and Tali; means, at least one element selected from alkaline earth metals; D is at least one element selected from the group comprising phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic, boron and zinc; E denotes at least one element selected from the group comprising silicon, aluminum, titanium and zirconium; O means oxygen; a, b, c, d, e, f, g, h, i and x denote the atomic relations of Mo, W, Bi, Fe, A, B, C, D, E, and O, respectively; and when a = 12, then 0 ≤ b ≤ 10, 0 < c ≤ 10 (preferably, of 0.1 ≤ b ≤ 10), 0 < d ≤ 10 (preferably, of 0.1 ≤ d ≤ 10), 2 ≤ e ≤ 15, 0 < f ≤ 10 (preferably of 0.001 < f ≤ 10), 0 ≤ g ≤ 10, 0 ≤ h ≤ 4 and 0 ≤ i ≤ 30; and meant the e x is determined by the oxidation States of the respective elements).

In the reaction of gas-phase catalytic oxidation when conducting secondary reactions (reaction conversion of unsaturated aldehyde to unsaturated acid), with the aim of oxidation acrolein obtaining acrylic acid, may be used a catalyst based on a mixed oxide of Mo-V. examples of the catalyst based on a mixed oxide of Mo-V include the compound represented by the General formula (II):

MoaVbWcCudXeYfOg(II)

(where Mo is molybdenum; V means vanadium; W denotes tungsten; Cu means copper; X is at least one element selected from the group comprising Mg, Ca, Sr and BA; Y represents at least one element selected from the group comprising Ti, Zr, Ce, Cr, Mn, Fe, Co, Ni, Zn, Nb, Sn, Sb, Pb and Bi; O means oxygen; a, b, c, d, e, f and g denote the atomic relations of Mo, V, W, Cu, X, Y and O, respectively; and when a = 12, then 2 ≤ b ≤ 14, 0 ≤ c ≤ 12, 0 < d ≤ 6, 0 ≤ e ≤ 3 and 0 ≤ f ≤ 3; and the value of g is determined by the oxidation States of the respective elements).

The above catalysts can be obtained by the methods disclosed in JP 63-054942 A, JP 06-013096B, H 06-038918B etc.

The catalyst used in the present invention may be formed by molding by extrusion or by the method of p is escolania in the form of tablets or can be a catalyst on the carrier, which is obtained by applying the mixed oxide catalyst composed of the catalyst components on an inert carrier such as silicon carbide, aluminum oxide, zirconium oxide or titanium oxide.

The shape of the catalyst used in the present invention is not specifically limited and may be spherical, columnar, cylindrical, star-shaped, ring-shaped, amorphous, etc.

The above catalyst may be used in combination with an inert substance, such as a diluent. The inert substance is not specifically limited, provided that the inert substance is stable in the reaction conditions and has no reactivity with respect to the original substance and the product. Specific examples of inert substances include such inert substances as aluminum oxide, silicon carbide, silicon oxide, zirconium oxide and titanium oxide.

The form of inert substances, by analogy with the catalyst is not limited, and it may be spherical, columnar, cylindrical, star-shaped, ring-shaped, fragmented, mixed, amorphous and the like, the Amount of inert substances can be set depending on the diameter of the reactor tube and differential pressure.

The amount of the inert substance, which serves as a diluent, determine rosolino depending on the desired catalytic activity.

Examples of the method of filling the catalyst and inert substances for these purposes include: a method which consists in dividing the Packed layer in the reactor tube, increasing the number of inert substances used in the part of the reactor tube, where the injected gas mixture of original substances, with the aim of decreasing the catalytic activity and suppressing the formation of heat, and reduce the amount of inert substances used in the part of the reactor tube, where removing the reaction gas mixture, in order to enhance catalytic activity and accelerate the reaction; and a method, which consists in filling the reactor tubes of a catalyst and an inert substance in a single layer with a fixed ratio mixing of the components.

Examples of changes of catalytic activity in the reactor tube include: regulation of the composition of the catalytic composition so that it was possible to use a catalyst with different catalytic activity; and the mixture of catalyst particles and particles of inert substances, with the aim of diluting the catalyst and the regulation of its catalytic activity.

Specific examples of two-layer filling include the use of a catalyst with a high proportion of particles of inert substances, i.e. in this case the proportion of particles of inert substances, for example the t from 0.3 to 0.7, in relation to the total number of nozzles in the part of the reactor tubes, where the injected gas mixture of original substances; and a catalyst, with a lower proportion of particles of inert substances (the proportion of particles of inert substances, for example, ranges from 0.5 to 1.0, relative to the total number of nozzles) for that part of the reaction gas mixture which is withdrawn from the reactor tubes.

The number of layers of catalyst, which is formed in the axial direction in novotrubnom the reactor with a fixed bed of catalyst is not specifically limited. However, too many layers of catalyst requires a large labor costs associated with filling of the catalyst, so that the number of layers of the catalyst is usually from 1 to 10. The thickness of each of the catalytic layers is determined arbitrarily depending on the type of catalyst, amount of catalyst, reaction conditions, etc.

A gas mixture containing propylene, propane, isobutylene and/or (meth)acrolein, a gas containing molecular oxygen, and water vapor mainly serves as a gas mixture of starting materials in Novotrubny reactor, which is used for the implementation of the reaction of gas-phase catalytic oxidation.

According to the present invention, the concentration of propylene, propane or isobutylene in the gas with the art of the original substance is from 6 to 10 mol.%. The oxygen concentration is from 1.5 to 2.5-fold molar excess relative to the concentration of propylene, propane or isobutylene, and the concentration of water vapor is from 0.8 to 5-fold excess relative to the concentration of propylene, propane or isobutylene. The supplied gas mixture of original substances distributed in the respective reactor tubes, passes through each reactor tube and reacts in the presence in them of the oxidation catalyst.

The heat exchanger 20 is not specifically limited, provided that it is a device for cooling the reaction gas mixture formed in the reactor 1. As the heat exchanger 20 may be any type of heat exchanger, such as Novotrubny the heat exchanger, plate heat exchanger or a spiral heat exchanger. The most preferred may be the use of novotrubnogo heat exchanger, which allows easy cleaning of the heat exchanger in the case when there is accumulation of high-boiling substances.

In this case, the reaction gas mixture can flow along the tubes and along the casing of the heat exchanger 20. However, the reaction gas mixture mainly flows along the tubes and thereby reduces the pressure drop in the reaction gas mixture and the region is gchat removal of sediment.

The flow rate of the gas mixture starting materials in novotrubnom the heat exchanger is from 5 to 25 m/s, mainly from 5 to 15 m/sec. Too little gas flow rate is undesirable and leads to increased adhesion of the high-boiling substance to the heat exchanger. Too high speed of the gas flow is undesirable and leads to increased pressure drop in the heat exchanger and thereby increases the pressure of the reaction.

The temperature of the coolant (refrigerant) in the heat exchanger 20 is in the range from 100 to 250°C., preferably from 120 to 200°C. Too low a temperature is undesirable because the heat energy of the reaction gas mixture cannot be allocated in the form of water vapor. Too high temperature is undesirable because it reduces the number of extracted thermal energy.

Examples of methods of cooling of the reaction gas mixture is cooled in the heat exchanger 20 includes: cooling with organic coolant; cooling with water under pressure; cooling with boiling water. In the present invention without particular problems can be used with any method.

Absorption tower 30 is a device for absorption of the absorbing liquid (meth)acrylic acid contained in the reaction gas mixture, put the m contact of the absorbing liquid, intended for the absorption of (meth)acrylic acid from the reaction gas mixture. As such absorption tower 30 can be used tower, which includes: an insertion opening for the reaction gas mixture in the lower part of the tower; the insertion opening for absorbing fluid in the upper part of the tower; a nozzle or plate located between the said holes; and a hole for drainage in the bottom of the tower.

Inside the absorption tower 30 is a nozzle or plate. Specific examples of dishes include nozzle plates, each of which have a drain Cup / tube sheet plates, cap plates, plates SUPERFRAC, diaphragm plates, plates MAX-FRAC and plates with dual flow without drain cups.

Examples of nozzles includes a nozzle stacked rows, and a nozzle in bulk. Examples of stacked rows of nozzles include: nozzle SULZER PACKING, supplied by Sulzer Brothers Ltd.; SUMITOMO SULZER PACKING, supplied by Sumitomo Heavy Industries, Ltd.; MELLAPAK, supplied by Sumitomo Heavy Industries, Ltd.; GEM-PAK supplied by Koch-Glitsch, LP; MONTZ-PAK supplied by Julius Montz GmbH; GOOD ROLL PACKING, supplied by Tokyo Tokushu Kanaami K.K.; HONEYCOMB PACK supplied by NGK Insulators, Ltd.; IMPULSE PACKING supplied by the company Nagaoka International Corporation; and MC PACK, supplied by Mitsubishi Chemical Engineering Corporation.

Examples of what Asadi in bulk include: INTALOX SADDLES, supplied by the company Saint-Gobain NorPro; TELLERETT supplied by Nittetsu Chemical Engineering Ltd.; PALL RINGS, supplied by BASF Aktiengesellschaft; CASCADE MINI-RING, supplied by Mass Transfer Ltd.; and FLEXI RINGS supplied by the company JGC Corporation.

The type of plates and nozzles in the present invention is not limited, and, in accordance with conventional practice, one or more types of each of the plates or nozzles can be used in combination with each other.

The absorbing liquid is not specifically limited, provided that it absorbs (meth)acrylic acid from the reaction gas mixture. Examples of such absorbing liquids include water, an organic solvent, such as diethyltartrate, and a mixture of water and an organic solvent.

The method of supplying absorption liquid in the absorption tower 30 is not specifically limited, provided that the method allows for the contacting of the reaction gas mixture from absorbing liquid. According to the present invention, it is possible to use any method, including: method of submission of the absorbing liquid, which is intended to come into contact with the reaction gas mixture, in the form of a counter current; a method of creating a parallel flow of the reaction gas mixture and absorbing fluid; and a process comprising contacting the reaction gas mixture with Zara is its sprayed absorbing liquid, the total cooling of the reagent and the absorbance of the reaction gas mixture through the absorbing fluid.

Air pipe 40 is not specifically limited, provided that it is a pipe connecting the reactor 1 and the absorption tower 30 without intermediate heat exchanger 20. Air pipe 40 may be directly attached to the main body of the heat exchanger 20 or attached to the pipeline, which is connected to the heat exchanger 20. Air pipe 40 may not be present in the singular, and can be used multiple bypass pipes.

Automatic valve 50 is a device for regulating the speed of flow of the reaction gas mixture which flows through the bypass pipe 40. In a variant design of the present invention apply the automatic valve 50, however, in the present invention may without limitation be applied to various devices, provided that the valve is a device capable of regulating the rate of flow of the reaction gas mixture in the bypass pipe 40. Examples of the device for controlling the flow rate, which can easily be used in the present invention include: valve, which is able to adjust the degree of its opening automatically; and a valve, the degree of opening of which the ore necessary, you can change manually.

Examples of the types of valves include ball valve, needle valve, shut-off valve and the throttle valve, but may be any valve, provided that it is capable of changing the degree of its opening.

Materials for different nozzles, body pillars, reboiler, piping, reflective gratings (including upper grille), etc. that represent the various components of the distillation columns used in the device for producing (meth)acrylic acid of the present invention, is chosen depending on the easily polymerizable compounds such as (meth)acrylate, starting compound to obtain and intermediate compounds, and temperature. However, according to the present invention, the material is not specifically limited, provided that the materials do not cause problems in the implementation of the methods of the present invention.

For example, as such materials for producing (meth)acrylic acid and (meth)acrylate, which is a typical easily polymerizable compounds, often use stainless steel, and these metals may be used as materials in the present invention. However, materials are not limited to stainless steels. Examples of materials for the various components include SUS 34, SUS 304L, SUS 316, SUS 316L, SUS 317, SUS 317L, SUS 327 and Hastelloy. The materials for the various components can be selected in accordance with the physical properties of each fluid with regard to corrosion resistance, etc.

In the reactor 1 of the above gas mixture of original substances fed into the housing 2 through the opening 4b, and then a gas mixture of original substances enters the reactor tube 1b and 1C, filled with the above catalyst, and thereby obtaining the (meth)acrylic acid. The reaction gas mixture containing the obtained (meth)acrylic acid, away from reactor 1 with a temperature of from 200 to 350°C.

The reaction gas mixture which take away from the reactor 1, is fed into the heat exchanger 20, is cooled and thereby dissipate heat energy from the reaction gas mixture. At the first stage of the automatic valve 50 may be completely closed.

The reaction gas mixture is cooled to 150-250°C in the heat exchanger 20, is fed into the absorption tower 30. The reaction gas mixture supplied to the absorption tower 30, rises up the tower from the bottom of the absorption tower 30 and comes into contact with an absorbing liquid (e.g. water), which is sprayed into the upper part of the absorption tower 30. The reaction gas mixture and the absorption liquid is effectively put into contact with each other by means of plates or nozzles in absor the traditional tower 30, and (meth)acrylic acid contained in the reaction gas mixture is absorbed by the absorbing liquid. An aqueous solution of (meth)acrylic acid obtained at the specified contacts, collect in the lower part of the absorption tower 30 and away from the absorption tower 30.

Components of gas mixtures, which are not absorbed by the absorption liquid in the absorption tower 30, discharged through the upper part of the absorption tower 30 and partially returned to the reactor 1 or enter the station detoxification, and then released into the atmosphere.

An aqueous solution of (meth)acrylic acid, which take away from the absorption tower 30, is subjected to dehydration, separating the low-boiling components, etc. the usual known manner and produce a purified acrylic acid from aqueous solution of (meth)acrylic acid.

Meanwhile, the reaction gas mixture which take away from the reactor 1 contains a substance with a high boiling point, such as maleic anhydride, terephthalic acid or trimellitate acid. Specified substance with a high boiling point sticks to the heat exchanger 20 and gradually increases the pressure drop in the heat exchanger 20. Thus, for continuous production gradually increases the pressure in the gas mixture of the original substances at the entrance to the reactor 1, the pressure inside the reactor tubes in re store 1 and the pressure at the outlet of the reactor 1.

When the pressure of the gas mixture of the original substances at the entrance to the reactor 1 is compared with the pressure, which serves the reaction gas mixture, the gas mixture of original substances hardly enters the reactor 1. Thus, the flow rate of the gas mixture starting materials in the reactor 1 should be reduced, so that the method could be implemented with reduced performance of the process of obtaining (meth)acrylic acid, or the process must be stopped for cleaning of the heat exchanger 20.

In a variant design of the present invention, the automatic valve 50 opens the loop pipe 40 in accordance with the reading of the pressure gauge 60 and thereby maintains a constant pressure of the gas mixture of the original substances at the entrance to the reactor 1. Thus, the pressure of the gas mixture of the original substances at the entrance to the reactor 1 is reduced and the production of (meth)acrylic acid can be continued without changing the feed rate of the gas mixture starting materials in the reactor 1.

Automatic valve 50 can continuously adjust the degree of its opening, or the operator may, if necessary, from time to time to alter the degree of opening of the valve in order to maintain a constant pressure in the reactor 1 or the constant feed rate of the gas mixture starting materials in the reactor 1.

Automatic valve 50 preemptive what about the completely closed at the beginning of the process, to increase the quantity of heat withdrawn from the reaction gas mixture. However, the automatic valve 50 can be opened immediately after the beginning of the process, in order to prevent clogging of the heat exchanger 20 and to adjust the temperature of the reaction gas mixture.

In particular, examples of the method of regulating the pressure of the gas mixture of original substances at the entrance to the reactor 1 includes: the method lies in the process from the beginning with an open automatic valve 50 by a fixed amount and in further gradual opening of the automatic valve 50, when the pressure of the gas mixture of the original substances at the entrance to the reactor 1 is increased due to the buildup of substances with high boiling point, and thus is maintained at a constant pressure of the gas mixture of the original substances at the entrance to the reactor 1; and the method lies in the gradual opening of the automatic valve 50, when the pressure of the gas mixture of the original substances at the entrance to the reactor 1 is compared with the pressure of the reaction gas mixture in the reactor 1, there are difficulties in the supply of the gas mixture of starting compounds and created obstacles to the safe production of (meth)acrylic acid, and thereby regulating the pressure of the gas mixture of the original substances at the entrance to the reactor 1. This method is a Ki is preferred from the viewpoint of maintaining constant performance of the process of obtaining (meth)acrylic acid.

In a variant design of the present invention the pressure of the gas mixture of the original substances at the entrance to the reactor 1 is determined with a pressure gauge 60 in order to adjust the degree of opening or closing of the automatic valve 50. However, the location and number of automatic valves 50 is not specifically limited, provided that the gauge may register pressure where the pressure inside the reactor 1 is increased due to clogging. To detect a difference in the rate of supply of the gas mixture starting materials in the reactor 1, the pressure gauge 60, mainly located at the entrance of the gas mixture starting materials in the reactor 1. However, the pressure gauge 60 may be located in any position within the reactor tubes 1b and 1C, at the exit of the reactor 1, the inside of the heat exchanger 20, in the intermediate space between the heat exchanger 20 and the reactor 1 and so on

In a variant design of the present invention decreases the feed rate of the gas mixture starting materials in the reactor 1 is determined with a pressure gauge 60, however, the registration device is not specifically limited, provided that the device is able to determine the feed rate of the gas mixture starting materials in the reactor 1. For example, instead of the pressure gauge 60 to determine the flow rate of the gas mixture source of substances with the same success can at enetica flow.

The design variant according to the present invention allows to dissipate heat energy from the reaction gas mixture; and to prevent a decrease in the rate of supply of the gas mixture starting materials in the reactor 1, which is caused by the clogging of the heat exchanger 20 and reduces the performance of the process of obtaining (meth)acrylic acid.

The design variant according to the present invention can be easily used in any existing installations, because the simple design of the bypass tube 40 and device for regulating the speed of flow of the reaction gas mixture in the bypass tube 40 allows: to withdraw heat energy from the reaction gas mixture and to prevent lowering of the yield of products.

EXAMPLES

<Example 1>

Acrylic acid is obtained by the reaction of gas-phase catalytic oxidation of propylene in the production installation is shown in figure 1. As reactor 1 used Novotrubny reactor, shown in figure 3.

The reactor tube novotrubnogo reactor in the first stage (the test description is designated as “first reactor”) is filled with a catalyst composed of a mixed oxide with an atomic ratio of Mo : Bi : Co : Ni : Fe : Na : Mg : B : K : Si= 12 : 5 : 2 : 3 : 0,4 : 0,1 : 0,4 : 0,2 : 0,08 : 24, which is disclosed in JP 06-013096 B as an oxidation catalyst for oxidation about Elena and the predominant obtain acrolein.

On the other hand, the reactor tube novotrubnogo reactor in the second stage (the test description is designated as “second reactor”) is filled with a catalyst composed of a mixed oxide with an atomic ratio of Mo : V : Nb : Sb : Sn : Ni : Cu : Si= 35 : 7 : 3 : 100 : 3 : 43 : 9 : 80, which is disclosed in JP 11-035519 And as a catalyst for oxidation of acrolein with the formation of acrylic acid.

Liquefied propylene is passed through the evaporator and fed into the reactor 1 in a gaseous state as the source connection. Oxygen, which is used for the implementation of the oxidation reaction, is fed into the reactor 1, compressing the air compressor. At the same time in the reactor 1 serves water vapor in order to prevent the formation of explosive concentration range of polypropylene. A gas mixture of original substances containing the above substances fed into the reactor 1 with the following fixed composition, vol.%:

Propylene8,0
The air68,6
water vapor23,4

The temperature in the first reactor filled with a catalyst for oxidation of polypropylene and obtain mainly acrolein support at UB is 320°C. Next, the temperature in the second reactor filled with a catalyst for oxidation of acrolein and obtain acrylic acid, supported at the level of 260°C.

Containing acrylic acid in the reaction gas mixture, which is discharged from the reactor 1, is cooled to 150°C with the formation of water vapor with a temperature of 130°C. using novotrubnogo heat exchanger 20 and served in the absorption tower 30 for extracting acrylic acid.

Absorption tower 30 for extracting acrylic acid is supplied with 50 bumper plates. Water, which is used as the absorbing liquid, spray towards the plates from the top of the tower, and acrylic acid from the reaction gas mixture fed to the absorption tower, and discharged in the form of an aqueous solution from the bottom of the plates.

At the beginning of the process pressure at the inlet of the reactor 1 is 60 kPa, but after 6 months the heat exchanger 20 at the entrance to the absorption tower 30 is partially blocked. The inlet pressure in the reactor 1 is increased to 70 kPa, which causes difficulties for the supply of the gas mixture of the starting materials. In the end, it becomes difficult to maintain a constant composition of the gas mixture starting materials in the reactor 1 and the flow rate of the gas mixture of the original substances at the entrance to the reactor 1.

Then the valve 50 installed in PBE the ne tube 40 of the heat exchanger 20 at the entrance to the absorption tower, opened to bring the pressure at the inlet to the first reactor 1 to a value of 60 kPa. A gas mixture of original substances may be filed with the original ratio of the components and with the original speed, and thereby it becomes possible to perform the continuous production of acrylic acid.

Applicability in industry

According to the present invention the use of a heat exchanger makes it possible to extract heat energy from the reaction gas mixture, and the regulation of the flow rate of the reaction gas mixture, which bypasses the heat exchanger, enables a stable supply of the gas mixture source material, even in the case where the precipitate adheres to the heat exchanger, and thereby ensures stable and continuous production of (meth)acrylic acid.

According to the present invention, the regulation of the flow rate of the gas mixture of the original substances flowing through the bypass pipe, to ensure almost constant pressure of the gas mixture of the original substances at the entrance to the reactor, it is more efficient from the point of view of the implementation of stable and continuous production of (meth)acrylic acid and prevent performance degradation of the process of obtaining (meth)acrylic acid.

1. Device for producing (meth)acrylic acid, which comprises:
the reactor for the production of (methacrylic acid by the reaction of gas-phase catalytic oxidation of one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein in the gas mixture of original substances, containing one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein and oxygen; coupled with the reactor, the heat exchanger used for cooling the reaction gas mixture containing the obtained (meth)acrylic acid; and
connected to the heat exchanger absorption tower, which is designed to contact the absorbing liquid, for the purpose of absorption of (meth)acrylic acid, and the reaction gas mixture so that the (meth)acrylic acid from the reaction gas mixture is absorbed by the absorbing liquid,
however, the installation further comprises:
the loop pipe, intended to connect the reactor and the absorption tower without the use of an intermediate heat exchanger; and
a device that regulates the flow rate, designed to regulate the speed of flow of the reaction gas mixture which flows through the bypass pipe;
where a device designed to regulate the speed of flow, regulates the flow rate of the reaction gas mixture which flows through the bypass pipe, thus to provide a virtually constant speed feed gas mixture source is exist in the reactor, or nearly constant pressure of the gas mixture of the original substances at the entrance to the reactor.

2. A method of obtaining a (meth)acrylic acid by extracting the (meth)acrylic acid, absorbed in the absorbing liquid, which comprises the following stages:
education (meth)acrylic acid in the reactor by the reaction of gas-phase catalytic oxidation of one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein in the gas mixture of original substances, containing one, two or more source compounds comprising propane, propylene, isobutylene and (meth)acrolein and oxygen;
the distribution of the reaction gas mixture formed of (meth)acrylic acid, in a heat exchanger designed to cool the reaction gas mixture in an absorption tower, which is intended for contacting the reaction gas mixture with an absorbing liquid, for the purpose of absorption of (meth)acrylic acid;
cooling of the reaction gas mixture fed to the heat exchanger, using the heat exchanger; and
the contacts inside the absorption tower of the reaction gas mixture is cooled in the heat exchanger and the reaction gas mixture supplied to the absorption tower at the stage of distribution, so that (meth)acrylic acid, soda is jamaca in the reaction gas mixture, absorbed by the absorbing liquid,
while the reaction gas mixture is distributed in such a way as to ensure that at the stage of distribution is almost constant speed feed gas mixture starting materials in the reactor, or nearly constant pressure of the gas mixture of the original substances at the entrance to the reactor.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: present invention pertains to improvement of the method of producing (met)acrylic acid or (met)acrolein using a multi-pipe reactor with a fixed bed. The reactor has several pipes, with at least one catalyst bed in the direction of the axis of the pipe. A heat carrier can regulate temperature outside the flow of the reaction pipe. In the reaction pipes, there is gas-phase catalytic oxidation of at least one type of oxidisable substance, propylene, propane, isobutylene and (met)acrolein by molecular oxygen or a gas, containing molecular oxygen. At the beginning of the process, the difference between the coolant temperature and the peak temperature of the catalyst is set in the interval 20-80°C, and during the process, peak temperature T(°C) of the catalyst in the direction of the axis of the pipe satisfies equation 1, given below: (equation 1), where L, T0, X and X0 stand for length of the reaction pipe, peak temperature of the catalyst in the direction of the axis of the pipe at the beginning of the process, the length up to the position which gives the peak temperature T at the input of the reaction pipe, and the length to the position which gives the peak temperature T0 at the input of the reaction pipe, respectively.

EFFECT: method allows for stable output of the target product, with high output for a long period of time, without reduction of catalyst activity.

3 dwg, 2 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to the improved method for preparing acrylic acid and selective oxidation of propylene to acrolein. Method involves carrying out reaction of propylene with oxygen in the first zone reaction with the first catalyst corresponding to the following formula: AaBbCcCadFeeBifMo12Ox wherein A means Li, Na, K, Rb and Cs and their mixtures also; B means Mg, Sr, Mn, Ni, Co and Zn and their mixtures also; C means Ce, Cr, Al, Sb, P, Ge, Sn, Cu, V and W and their mixtures also wherein a = 0.01-1.0; b and e = 1.0-10; c = 0-5.0 but preferably 0.05-5.0; d and f = 0.05-5.0; x represents a number determined by valence of other presenting elements. Reaction is carried out at enhanced temperature providing preparing acrylic acid and acrolein and the following addition of acrolein from the first reaction zone to the second reaction zone containing the second catalyst used for conversion of acrolein to acrylic acid. Method provides high conversion of propylene to acrylic acid and acrolein.

EFFECT: improved preparing method.

7 cl, 1 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: method is performed until at least one of such end products as acrylic acid, methacrylic acid are prepared that is ensured with supplying propane and/or iso-butane, molecular oxygen and a base mixture of reaction gas, containing at least one inert diluent gas at input pressure P1 at the stage of reaction being gas-impermeable with the exception of inlet for the base mixture of reaction gas, if required, other inlets for auxiliary gases, and also outlet for product gas mixture. At the specified stage of reaction, by supplying the base mixture of reaction gas at higher temperature propane and/or iso-butane are oxidised to at least one end product through the catalyst being in solid aggregate state and contained in the base mixture of reaction gas. Reaction gas mixture as containing at least one end product of product gas mixture is discharged from the reaction stage at outlet pressure P2, and at the same pressure P2 delivered to the processing stage being gas-impermeable with the exception of inlet for product gas mixture, if required, other inlets for auxiliary gases, and also outlet for residual product gas mixture. At the processing stage, the end product is coarsely separated from product gas mixture of the reaction stage thus forming the liquid phase, while residual product gas mixture containing propane and/or iso-butane, as well as, if required, propene and/or iso-butene, is delivered from the processing stage at inlet pressure P3, with P3 being less than P1. Propane or iso-butane from the residual product gas mixture is delivered back to the reaction stage where P1 is specified so that P3 is 1.5 bar or more. The residual product gas mixture is divided on two parts of the same composition with one part discharged. The other part is delivered as circulating gas and supplied back to the reaction stage as a component of the base mixture of reaction gas compressed to inlet pressure P1. The problem of heterogeneous catalytic partial direct oxidation consists in ensuring maxially higher conversion of propane and/or iso-butane at lowest temperatures and one-stage passage of reaction gas mixture through the reaction stage with simultaneous highest selectivity of end product and lowest energy consumption.

EFFECT: method improvement.

32 cl, 1 tbl, 1 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of recovering (meth)acrolein or (meth)acrylic acid, including stage of cooling of gaseous reaction mixture containing (meth)acrolein or (meth)acrylic acid obtained by reaction of catalytic oxidation in vapour phase of one or both reagents selected from (A) propane, propylene or isobutylene and (B) (meth)acrolein, with molecular oxygen or gas, containing molecular oxygen, to temperature 140-250°C; contacting of said gaseous reaction mixture with solvent, whose temperature is 20-50°C, in recovery installation for recovering (meth)acrolein or (meth)acrylic acid in solvent, where said recovery installation contains contact zone, where gaseous reaction mixture contacts with solvent, having transversal section of round form and many devices of gaseous reaction mixture supply for supplying gaseous reaction mixture into contact zone, devices of gaseous reaction mixture supply are installed in contact zone at the same height directed towards contact zone centre, gaseous reaction mixture is supplied to contact zone from devices of gaseous reaction mixture supply and is subjected to collision straight in one point of contact zone, and recovery installation does not have device which prevents direct collision of gaseous mixture supplied from devices of gaseous reaction mixture supply. Invention also relates to recovery installation for recovering (meth)acrolein or (meth)acrylic acid.

EFFECT: ensuring efficient recovering (meth)acrolein or (meth)acrylic acid from gas containing (meth)acrolein or (meth)acrylic acid, preventing polymerisation.

7 cl, 5 dwg, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of obtaining (meth)acrylic acid or (meth)acrolein, which includes process of catalytic gas-phase oxidation for obtaining (met)acrylic acid or (meth)acrolein by supplying propylene, propane or isobutylene and gas, containing molecular oxygen, into reactor, filled with catalyst, which contains composition of metal oxides, including Mo, where gas, containing molecular oxygen, is continuously supplied from outside on catalyst both during installation operation, and during stoppage of catalytic gas-phase oxidation process.

EFFECT: obtaining gaseous reaction product, which includes (meth)acrylic acid or (meth)acrolein, in which reduction of catalyst activity and selectivity of target product formation do not occur when installation operation is restarted after stoppage of catalytic gas-phase oxidation process.

2 cl, 2 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: object of the present invention is to develop method for making catalyst to produce methacrylic acid by gaseous catalytic oxidation of metacrolein, isobutyl aldehyde or isobutyric acid. There is disclosed method for making catalyst to produce methacrylic acid by gaseous catalytic oxidation of metacrolein, isobutyl aldehyde or isobutyric acid, involving as follows: (a) the stage of mixing water and compounds, each containing any Mo, V, P, Cu, Cs or NH4, to prepare aqueous solution or dispersed compounds (further, both mentioned as a suspension); (b) the stage of drying suspension produced at the stage (a), to make dry suspension; (c) the stage of burning dry suspension produced at the stage (b), to make burnt substance; (d) the stage of filtrating mixed burnt substance produced at the stage (c) and water to separate aqueous solution and water-insoluble substance; and (e) the stage of drying water-insoluble substance produced at the stage (d) to make dry water-insoluble substance; and (f) the stage of coating the carrier with dry water-insoluble substance produced at the stage (e), with using a binding agent to make coated mould product, and (g) the stage of burning coated mould product produced at the stage (f) in inert gas atmosphere, in the air or with reducing agent added.

EFFECT: making catalyst with long life, high activity and selectivity.

8 cl, 9 tbl, 9 ex

FIELD: chemistry.

SUBSTANCE: present invention pertains to improvement of the method of producing (met)acrylic acid and complex (met)acrylic esters, involving the following stages: (A) reacting propane, propylene or isobutylene and/or (met)acrolein with molecular oxygen or with a gas, containing molecular oxygen through gas-phase catalytic oxidation, obtaining crude (met)acrylic acid; (B) purification of the obtained crude (met)acrylic acid, obtaining a (met)acrylic acid product; and (C) reacting raw (met)acrylic acid with alcohol, obtaining complex (met)acrylic esters, in the event that the installation used in any of the stages (B) and (C), taking place concurrently, stops. The obtained excess crude (met)acrylic acid is temporarily stored in a tank. After restoring operation of the stopped installation, the crude (met)acrylic acid, stored in the tank, is fed into the installation, used in stage (B), and/or into the installation used in stage (C). (Met)acrylic acid output of the installation used in stage (A) should be less than total consumption of (met)acrylic acid by installations used in stages (B) and (C).

EFFECT: the method allows for processing (met)acrylic acid, temporarily stored in a tank, when stage (B) or (C) stops, without considerable change in workload in stage (A).

2 ex

FIELD: chemistry.

SUBSTANCE: present invention pertains to improvement of the method of producing (met)acrylic acid or (met)acrolein using a multi-pipe reactor with a fixed bed. The reactor has several pipes, with at least one catalyst bed in the direction of the axis of the pipe. A heat carrier can regulate temperature outside the flow of the reaction pipe. In the reaction pipes, there is gas-phase catalytic oxidation of at least one type of oxidisable substance, propylene, propane, isobutylene and (met)acrolein by molecular oxygen or a gas, containing molecular oxygen. At the beginning of the process, the difference between the coolant temperature and the peak temperature of the catalyst is set in the interval 20-80°C, and during the process, peak temperature T(°C) of the catalyst in the direction of the axis of the pipe satisfies equation 1, given below: (equation 1), where L, T0, X and X0 stand for length of the reaction pipe, peak temperature of the catalyst in the direction of the axis of the pipe at the beginning of the process, the length up to the position which gives the peak temperature T at the input of the reaction pipe, and the length to the position which gives the peak temperature T0 at the input of the reaction pipe, respectively.

EFFECT: method allows for stable output of the target product, with high output for a long period of time, without reduction of catalyst activity.

3 dwg, 2 ex

FIELD: chemistry.

SUBSTANCE: present invention pertains to improvement of the method of producing (met)acrylic acid or (met)acrolein using a multi-pipe reactor with a fixed bed. The reactor has several pipes, with at least one catalyst bed in the direction of the axis of the pipe. A heat carrier can regulate temperature outside the flow of the reaction pipe. In the reaction pipes, there is gas-phase catalytic oxidation of at least one type of oxidisable substance, propylene, propane, isobutylene and (met)acrolein by molecular oxygen or a gas, containing molecular oxygen. At the beginning of the process, the difference between the coolant temperature and the peak temperature of the catalyst is set in the interval 20-80°C, and during the process, peak temperature T(°C) of the catalyst in the direction of the axis of the pipe satisfies equation 1, given below: (equation 1), where L, T0, X and X0 stand for length of the reaction pipe, peak temperature of the catalyst in the direction of the axis of the pipe at the beginning of the process, the length up to the position which gives the peak temperature T at the input of the reaction pipe, and the length to the position which gives the peak temperature T0 at the input of the reaction pipe, respectively.

EFFECT: method allows for stable output of the target product, with high output for a long period of time, without reduction of catalyst activity.

3 dwg, 2 ex

FIELD: chemistry.

SUBSTANCE: present invention pertains to perfection of the method of obtaining at least, one product of partial oxidation and/or ammoxidising of propylene, chosen from a group, comprising propylene oxide, acrolein, acrylic acid and acrylonitrile. The starting material is raw propane. a) At the first stage, raw propane, in the presence and/or absence of oxygen, is subjected to homogenous and/or heterogeneous catalysed dehydrogenation and/or oxydehydrogenation. Gas mixture 1, containing propane and propylene is obtained. b) If necessary, a certain quantity of the other components in gas mixture 1, obtained in the first stage, besides propane and propylene, such as hydrogen and carbon monoxide is separated and/or converted to other compounds, such as water and carbon dioxide. From gas mixture 1, gas mixture 1' is obtained, containing propane and propylene, as well as other compounds, besides oxygen, propane and propylene. c) At the third stage, gas mixture 1 and/or gas mixture 1' as a component, containing molecular oxygen, of gas mixture 2, is subjected to heterogeneous catalysed partial gas-phase oxidation and/or propylene, contained in gas mixture 1 and/or gas mixture 1', undergoes partial gas-phase ammoxidising. Content of butane-1 in gas mixture 2 is ≤1 vol.%. The method increases output of desired products and efficiency of the process.

EFFECT: increased output of desired products and efficiency of the process.

72 cl, 10 ex

FIELD: heating.

SUBSTANCE: invention concerns improved method of catalytic oxidation in vapour phase which supplies effective removing of reactionary heat, excludes hot spot formation, and supplies effective receipt of base product. Method of catalytic oxidation is disclosed in the vapour phase (a) of propylene, propane or isobutene by the instrumentality of molecular oxygen for receiving (meth)acrolein, and/or oxidation (b) of (meth)acrolein by molecular oxygen for receiving (meth)acryl acid, by the instrumentality of multiple-tubular reactor, contained: cylindrical reactor vessel, outfitted by initial material supply inlet hole and discharge hole for product, variety of reactor coolant pipes, located around the cylindrical reactor vessel and used for insertion the heat carrier into cylindrical reactor vessel or for removing the heat carrier from it, circulator for connection of variety loop pipeline to each other, variety of reaction tube, mounted by the instrumentality of tube reactor lattices, with catalyst. Also multiple-tubular reactor contains: variety of partitions, located lengthways of reaction tubes and used for changing heat carrier direction, inserted into reactor vessel. According to this heat carrier coolant flow is analysed and there are defined zones in reactor which have heat-transfer coefficient of heat carrier less than 1000 W/(m2·K); also reaction of catalytic oxidation is averted in the vapour phase in mentioned zones of reactor and reaction of catalytic oxidation is implemented in the vapour phase in reactor.

EFFECT: receiving of improved method catalytic oxidation in vapour phase which supplies effective removing of reactionary heat, excludes hot spot formation, and supplies effective receipt of base product.

3 cl, 6 dwg, 2 ex

FIELD: industrial organic synthesis.

SUBSTANCE: invention relates to improved process to produce acrylic acid via heterogeneously catalyzed gas-phase partial oxidation of propane wherein starting reactive gas mixture containing propane, molecular oxygen, and at least one gas diluent is passed at elevated temperature over a multimetal oxide bulk depicted by total stoichiometry as Mo1VbM1сM2вOn (I), in which M1 = Te and/or Sb and M2 is at least one element from group comprising Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Ga, Fe, Ru, Co, Rh, Ni, Pd, Pt, La, Bi, B, Ce, Zn, Si, and In; b = 0.01 to 1, c = >0 to 1, d = >0 to 1, and n = number, which is determined by valence and number of non-oxygen elements in (I). Propane is partially oxidized to produce acrylic acid in a process wherein composition of starting reaction mixture is at least two times varied in the course of process such that molar percentage of gas diluent (water steam) in starting reaction gas mixture decreases relative to molar percentage of propane contained in starting gas mixture.

EFFECT: reduced amount of water steam in gas mixture without loss in selectivity and activity of catalyst regarding target product.

5 cl, 1 dwg, 10 ex

FIELD: chemistry.

SUBSTANCE: invention refers to advanced method of production of (meth)acrylic acid ester including (meth)acrylic acid purification by contacting raw (meth)acrylic acid containing manganese as an impurity manganese, and cation-exchange resin to remove manganese. To ensure contacting raw (meth)acrylic acid and cation-exchange resin, water is pre-added to (meth)acrylic acid. Besides, the method involves reaction of purified (meth)acrylic acid and alcohol with acid catalyst added.

EFFECT: method allows preventing effectively deactivation of the acid catalyst used in etherification reaction, equipment plugging and can ensure stable ester manufacturing.

3 cl, 5 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to improved method of recovering (meth)acrolein or (meth)acrylic acid, including stage of cooling of gaseous reaction mixture containing (meth)acrolein or (meth)acrylic acid obtained by reaction of catalytic oxidation in vapour phase of one or both reagents selected from (A) propane, propylene or isobutylene and (B) (meth)acrolein, with molecular oxygen or gas, containing molecular oxygen, to temperature 140-250°C; contacting of said gaseous reaction mixture with solvent, whose temperature is 20-50°C, in recovery installation for recovering (meth)acrolein or (meth)acrylic acid in solvent, where said recovery installation contains contact zone, where gaseous reaction mixture contacts with solvent, having transversal section of round form and many devices of gaseous reaction mixture supply for supplying gaseous reaction mixture into contact zone, devices of gaseous reaction mixture supply are installed in contact zone at the same height directed towards contact zone centre, gaseous reaction mixture is supplied to contact zone from devices of gaseous reaction mixture supply and is subjected to collision straight in one point of contact zone, and recovery installation does not have device which prevents direct collision of gaseous mixture supplied from devices of gaseous reaction mixture supply. Invention also relates to recovery installation for recovering (meth)acrolein or (meth)acrylic acid.

EFFECT: ensuring efficient recovering (meth)acrolein or (meth)acrylic acid from gas containing (meth)acrolein or (meth)acrylic acid, preventing polymerisation.

7 cl, 5 dwg, 4 ex

FIELD: chemistry.

SUBSTANCE: method of (meth)acrylic acid purification includes the stages as follows: distillations of the liquid containing raw (meth)acrylic acid being acrylic acid or methacrylic acid with one or more polymerisation inhibitors added as chosen from group consisting of phenol derivative, phenothiazine derivative, copper (meth)acrylate and copper dithiourethane, for the purpose to produce condensate of (meth)acrylic acid, containing (meth)acrylic acid of purity at least 90%; adding polymerisation inhibitor containing phenol derivative to condensate; and delivery of oxygen-containing gas that contains oxygen to condensate of (meth)acrylic acid in reflux tank wherein condensate of (meth)acrylic acid is collected, wherein oxygen-containing gas is delivered to condensate in reflux tank with using small-size bubble liquid injector, and pressure connection for oxygen-containing gas delivery to liquid injector whereat ratio (nm/tn) of oxygen delivery in oxygen-containing gas and condensate flow supplied to reflux tank at 0°C, 1 atm complies with ratio shown in equation 0.004≤A/B≤1.0, where A stands for O2 delivery (nm3/hour), B stands for condensate flow (tn/hour) of the condensate supplied to reflux tank, and symbol n in nm3/hour specifies the value under normal conditions (0°C, 1 atm: normal conditions).

EFFECT: effective method of high purity acid production wherein acid polymer formation in made condensate is prevented.

12 cl, 6 dwg, 7 ex

FIELD: chemistry.

SUBSTANCE: method of obtaining product - purified carboxylic acid, includes: (a) oxidation of aromatic initial materials in primary oxidation zone with formation of raw carboxylic acid suspension; where raw carboxylic acid suspension contains terephthalic acid; where said oxidation is carried out at temperature within the range from 120°C to 200°C; (b) withdrawal of admixtures from raw suspension of carboxylic acid, removed at temperature from 140°C to 170°C from stage of oxidation of paraxylol in primary oxidation zone and containing terephthalic acid, catalyst, acetic acid and admixtures, realised in zone of solid products and liquid separation with formation of mother liquid flow and product in form of suspension; where part of said catalyst in said suspension of raw carboxylic acid is removed in said mother liquid flow; and where into said zone of solid products and liquid separation optionally additional solvent is added; (c) oxidation of said product in form of suspension in zone of further oxidation with formation of product of further oxidation; where said oxidation is carried out at temperature within the range from 190°C to 280°C; and where said oxidation takes place in said zone of further oxidation at temperature higher than in said primary oxidation zone; (d) crystallisation of said product of further oxidation in crystallisation zone with formation of crystallised product in form of suspension; (e) cooling of said crystallised product in form of suspension in cooling zone with formation of cooled suspension of purified carboxylic acid; and (i) filtration and optionally drying of said cooled suspension of purified carboxylic acid in filtration and drying zone in order to remove part of solvent from said cooled suspension of carboxylic acid with obtaining of said product - purified carboxylic acid.

EFFECT: purified carboxylic acid with nice colour and low level of admixtures, without using stages of purification like hydration.

8 cl, 1 tbl, 1 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: method lies in the following: concentrated solution of lithium salt is introduced into mixture of sodium salts of naphthenic acids, mixed and left for separation into layers and formation of viscous mass of lithium salt of naphthenic acid high-molecular fraction with molecular weight more than 200 in sediment, and in upper water layer - of low-molecular fraction of naphthenic acids lithium salt with molecular weight less than 200, with subsecutive separation.

EFFECT: separation of concentrated water solutions of naphthetic acids lithium salts according to their molecular weight.

2 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method, by which the carboxylic acid/diol mixture, that is suitable as the initial substance for the manufacture of polyester, obtained from the decolourised solution of carboxylic acid without actually isolating the solid dry carboxylic acid. More specifically, the invention relates to the method of manufacturing a mixture of carboxylic acid/diol, where the said method includes the addition of diol to the decolourised solution of carboxylic acid, which includes carboxylic acid and water, in the zone of the reactor etherification, where diol is located at a temperature sufficient for evaporating part of the water in order to become the basic suspending liquid with the formation of the specified carboxylic acid/diol mixture; where the said carboxylic acid and diol enter into a reaction in the zone of etherification with the formation of a flow of a complex hydroxyalkyl ether. The invention also relates to the following variants of the method: the method of manufacture of the carboxylic acid/diol mixture, where the said method includes the following stages: (a) mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of damp carboxylic acid; where the said carboxylic acid is selected from the group, which includes terephthalic acid, isophthatic acid, naphthalenedicarboxylic acid and their mixtures; (b) discolourisation of aforesaid solution of damp carboxylic acid in the zone for reaction obtaining the decolourised solution of carboxylic acid; (c) not necessarily, instantaneous evaporation of the said decolourised solution of carboxylic acid in the zone of instantaneous evaporation for the removal of part of the water from the decolourised solution of carboxylic acid; and (d) addition of diol to the decolourised solution of carboxylic acid in the zone of the reactor of the etherification, where the said diol is located at a temperature, sufficient for the evaporation of part of the water in order to become the basic suspending liquid with the formation of the carboxylic acid/diol mixture; where the aforesaid carboxylic acid and diol then enter the zone of etherification with the formation of the flow of complex hydroxyalkyl ether; and relates to the method of manufacture of carboxylic acid/diol, where the said method includes the following stages: (a) the mixing of the powder of damp carboxylic acid with water in the zone for mixing with the formation of the solution of carboxylic acid; (b) discolourisation of the said solution of damp carboxylic acid in the reactor core with the formation of the decolourised solution of carboxylic acid; (c) crystallisation of the said decolourised solution of carboxylic acid in the zone of crystallisation with the formation of an aqueous suspension; and (d) removal of part of the contaminated water in the aforesaid aqueous solution and addition of diol into the zone of the removal of liquid with the obtaining of the said carboxylic acid/diol mixture, where diol is located at a temperature sufficient for evaporating part of the contaminated water from the said aqueous suspension in order to become the basic suspending liquid.

EFFECT: obtaining mixture of carboxylic acid/diol.

29 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: invention pertains to the perfection of the method of regulating quantities of dissolved iron in liquid streams during the process of obtaining aromatic carboxylic acids or in the process of cleaning technical aromatic carboxylic acids, characterised by that, to at least, part of the liquid stream for regulating the quantity of dissolved iron in it, at least one peroxide with formula R1-O-O-R2 is added. Here R1 and R2 can be the same or different. They represent hydrogen or a hydrocarbon group, in quantities sufficient for precipitation of the dissolved iron from the liquid. The invention also relates to the perfection of the method of obtaining an aromatic carboxylic acid, through the following stages: A) contacting the crude aromatic material which can be oxidised, with molecular oxygen in the presence of an oxidising catalyst, containing at least, one metal with atomic number from 21 to 82, and a solvent in the form of C2-C5 aliphatic carboxylic acid in a liquid phase reaction mixture in a reactor under conditions of oxidation with formation of a solid product. The product contains technical aromatic carboxylic acid, liquid, containing a solvent and water, and an off-gas, containing water vapour and vapour of the solvent; B) separation of the solid product, containing technical aromatic carboxylic acid from the liquid; C) distillation of at least part of the off gas in a distillation column, equipped with reflux, for separating vapour of the solvent from water vapour. A liquid then forms, containing the solvent, and in the upper distillation cut, containing water vapour; D) returning of at least, part of the liquid from stage B into the reactor; E) dissolution of at least, part of the separated solid product, containing technical aromatic carboxylic acid, in a solvent from the cleaning stage with obtaining of a liquid solution of the cleaning stage; F) contacting the solution from the cleaning stage with hydrogen in the presence of a hydrogenation catalyst and under hydrogenation conditions, sufficient for formation of a solution, containing cleaned aromatic carboxylic acid, and liquid, containing a cleaning solvent; G) separation of the cleaned aromatic carboxylic acid from the solution, containing the cleaning solvent, which is obtained from stage E, with obtaining of solid cleaned aromatic carboxylic acid and a stock solution from the cleaning stage; H) retuning of at least, part of the stock solution from the cleaning stage, to at least, one of the stages B and E; I) addition of at least, one peroxide with formula R1-O-O-R2, where R1 and R2 can be the same or different, and represent hydrogen or a hydrocarbon group, in a liquid from at least one of the other stages, or obtained as a result from at least one of these stages, to which the peroxide is added, in a quantity sufficient for precipitation of iron from the liquid.

EFFECT: controlled reduction of the formation of suspension of iron oxide during production of technical aromatic acid.

19 cl, 1 dwg, 6 ex, 4 tbl

FIELD: organic chemistry.

SUBSTANCE: invention relates to method for purification of monochloroacetic acid from dichloroacetic acid impurities. Claimed method includes hydrogenolysis in presence of hydrogen in film regime at 135-145°C in cascade of sequentially bonded reactors with fixed bed of heterogeneous catalyst namely palladium on activated carbon. Preferably reactor cascade with intermediate cooling with cold flow of monochloroacetic acid as cooling agent is used.

EFFECT: simplified process; product of improved quality.

3 cl, 7 ex, 3 dwg

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