CN219333185U - Methyl benzoic acid production system - Google Patents

Abstract

The utility model provides a methyl benzoic acid production system. The methylbenzoic acid production system comprises: a reaction subsystem and a rectification subsystem, the rectification subsystem comprising: the light component removing device comprises a light component removing tower, a light component removing condenser, a light component removing reflux tank and a light component removing control valve, wherein the top of the light component removing tower, the light component removing condenser and the light component removing reflux tank are sequentially communicated and form a circulating loop, and the light component removing control valve is arranged on a communication path between the light component removing reflux tank and the light component removing tower; the weight removing device comprises a weight removing tower, a weight removing condenser, a weight removing reflux tank and a weight removing control valve, wherein the tower top of the weight removing tower, the weight removing condenser and the weight removing reflux tank are sequentially communicated and form a circulating loop, and the weight removing control valve is arranged on a communication path between the weight removing reflux tank and the weight removing tower. The methylbenzoic acid production system of the technical scheme can solve the problems of long reaction time and low production efficiency caused by intermittent production of methylbenzoic acid by adopting the existing production system.

Description

Methyl benzoic acid production system

Technical Field

The utility model relates to the technical field of chemical substance production, in particular to a methylbenzoic acid production system.

Background

In the prior art known by the inventor, the intermittent method is mostly adopted to produce the methylbenzoic acid, namely, dimethylbenzene is added into a bubbling tower and air is introduced to carry out oxidation reaction, so that the target product methylbenzoic acid is produced, and main byproducts comprise methylbenzaldehyde, methylbenzyl alcohol, phthalic acid, benzoic acid and the like. The specific process flow is as follows: and (3) injecting quantitative dimethylbenzene raw material into the bubbling tower, heating, and then introducing compressed air from the bottom of the bubbling tower to perform reaction induction. After the reaction starts, the air inlet amount is increased, and the required reaction temperature is controlled. Unreacted air carries unreacted raw materials and water generated by the reaction to enter a condenser at the top of the bubbling tower, and the raw materials and the water are condensed and then enter a water separation bag for separation. And after the oxidation reaction of the dimethylbenzene in the bubbling tower reaches a certain time, reducing the air inlet amount and properly cooling, and finally stopping the air inlet to stop the oxidation reaction. And conveying the crude product after reaction in the bubbling tower into a distillation tower kettle, enabling the xylene steam generated after heating to enter a condenser at the top of the distillation tower, condensing and recycling unreacted xylene, and returning to the bubbling tower for continuous reaction. And conveying residues in the distillation tower to a rectification tower, heating to generate front fraction steam, and conveying the front fraction steam to a condenser at the top of the rectification tower to collect front fraction. And then increasing the reflux ratio, and enabling the generated methylbenzoic acid steam to enter a condenser at the top of the rectifying tower, and collecting the methylbenzoic acid after condensation. And finally, the residue in the rectifying tower is high-boiling residues and a small amount of methylbenzoic acid, and the residue is discharged to a waste residue tank from the rectifying tower.

Most of the existing production systems for preparing the methylbenzoic acid are production systems corresponding to batch processes, a large amount of raw materials are required to be pumped into a bubbling tower for reaction, the reaction time is long, and the production efficiency is low.

Disclosure of Invention

The utility model mainly aims to provide a methylbenzoic acid production system which can solve the problems of long reaction time and low production efficiency caused by intermittent production of methylbenzoic acid by adopting the existing production system.

In order to achieve the above object, according to an aspect of the present utility model, there is provided a methylbenzoic acid production system comprising: a reaction subsystem; and a rectification subsystem in communication with the reaction subsystem, the rectification subsystem comprising: the light component removing device comprises a light component removing tower, a light component removing condenser, a light component removing reflux tank and a light component removing control valve, wherein the top of the light component removing tower, the light component removing condenser and the light component removing reflux tank are sequentially communicated and form a circulation loop; the weight removing device comprises a weight removing tower, a weight removing condenser, a weight removing reflux tank and a weight removing control valve, wherein the tower top of the weight removing tower, the weight removing condenser and the weight removing reflux tank are sequentially communicated and form a circulation loop, and the weight removing control valve is arranged on a communication path of the weight removing reflux tank and the weight removing tower so as to control the amount of materials flowing back to the weight removing tower, and the tower bottom of the weight removing tower is communicated with an inlet of the weight removing tower.

Further, the light component removing device also comprises a light component removing reflux pump which is arranged on the communication path between the light component removing reflux tank and the light component removing tower; and/or the weight removing device further comprises a weight removing reflux pump, and the weight removing reflux pump is arranged on a communication path between the weight removing reflux tank and the weight removing tower.

Further, the light component removing device also comprises a light component removing extraction pipeline which is communicated with a communicating pipeline between the light component removing reflux tank and the light component removing tower; and/or the weight removing device further comprises a weight removing extraction pipeline which is communicated with a communicating pipeline between the weight removing reflux tank and the weight removing tower.

Further, the reaction subsystem comprises an oxidation reactor and a reflux device, the reflux device comprises a gas-liquid separator and a tail gas condenser, an inlet of the gas-liquid separator is communicated with an outlet of the oxidation reactor, and a light phase outlet of the gas-liquid separator, the tail gas condenser and the inlet of the oxidation reactor are sequentially communicated and form a circulation loop.

Further, the reflux device also comprises a circulating liquid-liquid phase separator, the circulating liquid-liquid phase separator is arranged on a communication path between the tail gas condenser and the oxidation reactor, an inlet of the circulating liquid-liquid phase separator is communicated with an outlet of the tail gas condenser, and an organic phase outlet of the circulating liquid-liquid phase separator is communicated with an inlet of the oxidation reactor.

Further, the reflux device further comprises a recovery storage tank and a recovery feed pump, and the recovery storage tank and the recovery feed pump are both arranged on a communication path between the circulating liquid-liquid phase separator and the oxidation reactor.

Further, the rectification subsystem further comprises a continuous concentration device, the continuous concentration device comprises a continuous concentrator and a concentration receiving tank, the heavy phase outlet of the gas-liquid separator and the heavy phase outlet of the concentration receiving tank are both communicated with the inlet of the continuous concentrator, the outlet of the continuous concentrator is communicated with the inlet of the concentration receiving tank, and the heavy phase outlet of the concentration receiving tank is also communicated with the inlet of the light component removal tower.

Further, the continuous concentration device further comprises a concentration condenser and a concentrated liquid phase separator, wherein the light phase outlet of the concentration receiving tank, the concentration condenser and the concentrated liquid phase separator are sequentially communicated, and the organic phase outlet of the concentrated liquid phase separator is communicated with the inlet of the oxidation reactor.

Further, the reaction subsystem further comprises a raw material storage tank, a catalyst storage tank, a batching device and an air compressor, wherein the outlets of the raw material storage tank and the catalyst storage tank are communicated with the inlet of the batching device, and the outlets of the air compressor and the batching device are communicated with the oxidation reactor.

Further, the reaction subsystem also comprises a mixing storage tank, and the mixing storage tank is arranged on a communication path between the batching device and the oxidation reactor.

By applying the technical scheme of the utility model, the light component removing process and the heavy component removing process are respectively realized through the light component removing device and the heavy component removing device, so that the light component removing tower and the heavy component removing tower can work simultaneously, and the methyl benzoic acid is continuously produced, thereby realizing the serialization. In addition, the light phase components produced by the light phase outlet of the light component removing tower need to be condensed and then returned to the light component removing tower for reaction, and in order to ensure the continuity, the reaction time of the light component removing tower needs to be ensured to be short only when the quantity of the reactant materials in the light component removing tower is within a preset range, therefore, a light component removing reflux tank and a light component removing control valve are arranged, the light phase components produced by the light component removing tower firstly enter the light component removing reflux tank for temporary storage, and the light phase components are gradually introduced into the light component removing tower through the light component removing control valve according to the requirement of the quantity of the reactant materials in the light component removing tower, so that the quantity of the reactant materials in the light component removing tower is always within the preset range, and the light component removing tower is ensured to realize continuous reaction; and in the same way, a weight-removing reflux tank and a weight-removing control valve are arranged, so that continuous reaction of the weight-removing tower can be realized. Through the arrangement of the weight removing device and the weight removing device, the production process of the methylbenzoic acid can realize continuity, the amount of materials entering the weight removing tower and the weight removing tower for single reaction is reduced, the reaction time is shortened, and the production efficiency is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model. In the drawings:

FIG. 1 shows a schematic connection diagram of a methylbenzoic acid production system of an embodiment of the present utility model.

Wherein the above figures include the following reference numerals:

101. a recovery storage tank; 102. an air compressor; 103. a raw material storage tank; 104. a catalyst storage tank; 105. a batching device; 106. a mixing tank; 107. an oxidation reactor; 108. a gas-liquid separator; 109. a tail gas condenser; 110. a circulating liquid-liquid phase separator; 111. a recovery feed pump; 201. a continuous concentrator; 202. a concentrating receiving tank; 203. a concentrating condenser; 204. a concentrate-liquid phase separator; 205. a concentration vacuum pump; 206. a light component removing tower; 207. a light-off condenser; 208. a light trap; 209. a light reflux drum; 210. a light-off control valve; 211. a light reflux pump; 212. a light extraction pipeline; 301. a light vacuum pump; 302. a weight removing tower; 303. a weight removing catcher; 304. a de-weighting vacuum pump; 305. a heavy-removal reflux tank; 306. a de-duplication condenser; 307. a weight-removing control valve; 308. a heavy-removal reflux pump; 309. and (5) removing the heavy extraction pipeline.

Detailed Description

It should be noted that, without conflict, the embodiments of the present utility model and features of the embodiments may be combined with each other. The utility model will be described in detail below with reference to the drawings in connection with embodiments.

Referring to fig. 1, the present utility model provides a methylbenzoic acid production system comprising: a reaction subsystem; and a rectification subsystem in communication with the reaction subsystem, the rectification subsystem comprising: the light component removing device comprises a light component removing tower 206, a light component removing condenser 207, a light component removing reflux tank 209 and a light component removing control valve 210, wherein the top of the light component removing tower 206, the light component removing condenser 207 and the light component removing reflux tank 209 are sequentially communicated and form a circulation loop, and the light component removing control valve 210 is arranged on the communication path between the light component removing reflux tank 209 and the light component removing tower 206 so as to control the quantity of materials which are refluxed to the light component removing tower 206; and a weight removing device, comprising a weight removing tower 302, a weight removing condenser 306, a weight removing reflux drum 305 and a weight removing control valve 307, wherein the top of the weight removing tower 302, the weight removing condenser 306 and the weight removing reflux drum 305 are sequentially communicated and form a circulation loop, the weight removing control valve 307 is arranged on the communication path between the weight removing reflux drum 305 and the weight removing tower 302 to control the amount of materials flowing back to the weight removing tower 302, and the tower bottom of the weight removing tower 206 is communicated with the inlet of the weight removing tower 302.

In this embodiment, the light removal process is implemented by a light removal device, the heavy removal process is implemented by a heavy removal device, and the heavy removal tower 302 can perform the heavy removal process while the light removal tower 206 performs the light removal process, that is, the light removal process and the heavy removal process can be performed simultaneously, compared with the mode that the light removal process and the heavy removal process are implemented by a rectifying tower in the prior art, in this embodiment, the light removal process and the heavy removal process are performed by two devices respectively, so that the continuity of production can be realized. In addition, the light phase component produced at the light phase outlet of the light component removing tower 206 needs to be condensed and then returns to the light component removing tower 206 for reaction again, so as to ensure the maximum output of the reaction materials, and in order to ensure the continuity, the reaction time of the light component removing tower 206 needs to be ensured to be short within a predetermined range, and the continuity of production is further realized, therefore, the light phase component produced by the light component removing tower 206 is firstly sent to the light component removing reflux tank 209 for temporary storage, the light phase component is gradually sent to the light component removing tower 206 from the top of the light component removing tower 206 through the light component removing control valve 210 according to the requirement of the amount of the reaction materials of the light component removing tower 206, so that the amount of the reaction materials in the light component removing tower 206 is always within the predetermined range, and the light component removing tower 206 is ensured to realize continuous rectification. Similarly, the light phase component produced at the light phase outlet of the heavy-removal column 302 needs to be condensed and then returns to the heavy-removal column 302 again for rectification so as to ensure the maximum yield of the reaction materials, and in order to ensure the continuity, the reaction time of the heavy-removal column 302 needs to be ensured to be short so as to realize continuity, therefore, the heavy-removal reflux tank 305 and the heavy-removal control valve 307 are arranged, the light phase component produced by the heavy-removal column 302 firstly enters the heavy-removal reflux tank 305 for temporary storage, the light phase component is gradually introduced into the heavy-removal column 302 from the top of the heavy-removal column 302 through the heavy-removal control valve 307 according to the requirement of the yield of the reaction materials of the heavy-removal column 302, and the yield of the reaction materials in the heavy-removal column 302 is ensured to be always in the preset range so as to ensure that the heavy-removal column 302 can realize continuous rectification.

By arranging the weight removing device and the weight removing device, on one hand, the production process of the methylbenzoic acid can realize continuity, the amount of materials entering the weight removing tower 206 and the weight removing tower 302 for single reaction is reduced, the reaction time is shortened, and the production efficiency is improved; on the other hand, due to the reduced amount of reaction materials, the volume of the light component removal column 206 is reduced compared with the volume of the rectifying column in the prior art, and the volume of the heavy component removal column 302 is also reduced compared with the volume of the rectifying column in the prior art, so that the manufacturing cost of the light component removal column 206 or the heavy component removal column 302 is reduced, and the cost is reduced; on the other hand, since the amounts of the reaction materials in the light component removal column 206 and the heavy component removal column 302 are reduced, the reaction time is also reduced, that is, the time for heating the materials is reduced, and it is possible to avoid the low yield of the reaction materials due to the excessively long heating time.

The light phase outlet of the light phase removal column 206 is located at the top of the light phase removal column 206, and the light phase outlet of the heavy phase removal column 302 is located at the top of the heavy phase removal column 302. The rectification material is the material entering the light component removal tower 206 or the heavy component removal tower 302 for rectification.

Specifically, a pump is disposed on a communication path between the bottom of the light component removal column 206 and the inlet of the heavy component removal column 302 to provide power for the feed liquid produced by the bottom of the light component removal column 206 to be fed to the heavy component removal column 302.

Specifically, the gas phase outlet of the lightness-removing condenser 207 is communicated with a lightness-removing trap 208 and a lightness-removing vacuum pump 301, and the lightness-removing trap 208 is used for cooling the light phase component of the lightness-removing column 206 again; the tower top operation temperature of the light component removal tower 206 is 80-140 ℃, the tower bottom operation temperature of the light component removal tower 206 is 140-170 ℃, and the operation pressure is-0.07-0.098 MPa. The gas phase outlet of the de-weight condenser 306 is communicated with a de-weight catcher 303 and a de-weight vacuum pump 304, and the de-weight catcher 303 is used for cooling the light phase component of the de-weight tower 302 again; the tower top operation temperature of the weight removing tower 302 is 150-180 ℃, the tower bottom operation temperature of the weight removing tower 302 is 180-250 ℃, and the operation pressure is-0.07 MPa to-0.098 MPa.

Referring to fig. 1, in one embodiment of the present utility model, the light component removing apparatus further includes a light component removing reflux pump 211, wherein the light component removing reflux pump 211 is disposed on a communication path between the light component removing reflux drum 209 and the light component removing tower 206; the de-duplication apparatus further includes a de-duplication reflux pump 308, and the de-duplication reflux pump 308 is provided in a communication path between the de-duplication reflux drum 305 and the de-duplication column 302.

In this embodiment, the light component removing reflux pump 211 is used to provide power for the condensed light phase component in the light component removing reflux tank 209, so that the light phase component can smoothly reflux into the light component removing tower 206, and rectification processing is repeated to fully utilize the reaction materials in the light component removing tower 206. Similarly, the heavy-removal reflux pump 308 is used for providing power for the condensed light phase component in the heavy-removal reflux tank 305, so that the light phase component can smoothly reflux into the heavy-removal column 302, and rectification is repeatedly performed, so that the rectified material in the heavy-removal column 302 is fully utilized.

Referring to fig. 1, in one embodiment of the present utility model, the light component removing device further includes a light component removing extraction pipe 212, and the light component removing extraction pipe 212 is connected to a communication pipe between the light component removing reflux drum 209 and the light component removing tower 206; the de-duplication apparatus further includes a de-duplication extraction pipe 309, and the de-duplication extraction pipe 309 is connected to a connection pipe between the de-duplication reflux drum 305 and the de-duplication column 302.

In this embodiment, the light extraction pipeline 212 is provided with a valve, on one hand, when the condensed light phase component is filled in the light reflux tank 209, so that the light reflux tank 209 cannot continuously accommodate more condensed light phase components, the valve on the light extraction pipeline 212 can be opened to output the condensed light phase component in the light reflux tank 209, so that the light reflux tank 209 can continuously accommodate more condensed light phase components; on the other hand, the light phase components produced from the light phase outlet of the light phase removal column 206 are residual meta-xylene, methylbenzyl alcohol and methylbenzaldehyde, and when other processes need the light phase components, the valve on the light phase removal extraction pipeline 212 can be opened to output the condensed light phase components in the light phase removal reflux tank 209 to the corresponding process positions.

The valve is also arranged on the heavy-removal extraction pipeline 309, the light phase component produced from the light phase outlet of the heavy-removal tower 302 is unreacted complete reaction material and gaseous methylbenzoic acid, wherein the gaseous methylbenzoic acid forms a methylbenzoic acid product after passing through the heavy-removal condenser 306, and at the moment, the valve on the heavy-removal extraction pipeline 309 is opened, so that the methylbenzoic acid product can be output, and the operations such as subsequent slicing and the like can be performed.

Referring to fig. 1, in one embodiment of the present utility model, the reaction subsystem includes an oxidation reactor 107 and a reflux device, the reflux device includes a gas-liquid separator 108 and a tail gas condenser 109, an inlet of the gas-liquid separator 108 is communicated with an outlet of the oxidation reactor 107, and a light phase outlet of the gas-liquid separator 108, the tail gas condenser 109 and an inlet of the oxidation reactor 107 are sequentially communicated and form a circulation loop.

In this embodiment, the substances produced from the outlet of the oxidation reactor 107 enter the gas-liquid separator 108 to perform gas-liquid separation, the substances include a light phase component and a heavy phase component, the gas-liquid separator 108 separates the light phase component from the heavy phase component, most of the light phase component enters the tail gas condenser 109 to be condensed, the condensed light phase component enters the oxidation reactor 107 again to perform oxidation reaction, so that the oxidized substances can be fully reacted, the utilization rate of the oxidized substances is improved, the material loss is saved, and the oxidized substances are the mixed materials in the following mixed storage tank 106.

Specifically, the light phase component of the gas-liquid separator 108 is unreacted air in the oxidation reactor 107 carrying unreacted xylene and water produced by the reaction; the heavy phase component of the gas-liquid separator 108 is the crude product of methyl benzoic acid generated by the reaction in the oxidation reactor 107 and a part of the mixture which is not completely reacted. The tail gas condenser 109 includes a gas phase outlet and a liquid phase outlet, the gas phase outlet generates air carrying a small amount of uncondensed xylene after the light phase component of the gas-liquid separator 108 is condensed by the tail gas condenser 109, the air is adsorbed by an activated carbon adsorption device (not shown) and then is emptied, and the liquid phase outlet generates xylene and water.

Specifically, the gas-liquid separator 108 is one of separation devices employing separation principles such as baffle separation, cyclone separation, and packed separation.

Referring to fig. 1, in one embodiment of the present utility model, the reflux apparatus further includes a circulating liquid-liquid phase separator 110, the circulating liquid-liquid phase separator 110 is disposed on a communication path between the off-gas condenser 109 and the oxidation reactor 107, an inlet of the circulating liquid-liquid phase separator 110 is communicated with an outlet of the off-gas condenser 109, and an organic phase outlet of the circulating liquid-liquid phase separator 110 is communicated with an inlet of the oxidation reactor 107.

In this embodiment, the mixture condensed by the tail gas condenser 109 enters the circulating liquid-liquid phase separator 110, and after liquid-liquid phase separation, an organic phase and waste water are formed, the organic phase is conveyed into the oxidation reactor 107 through a pipeline to continue oxidation reaction, and the waste water is discharged from the circulating liquid-liquid phase separator 110. The water cannot perform oxidation reaction in the oxidation reactor 107, and affects the occurrence of the reaction, the more water is contained in the raw materials, the slower the reaction progress, and the oxidation rate of the intermediate state converted into a product is directly affected, resulting in the reduction of the whole production efficiency. Therefore, the water generated by the reaction is discharged through the circulating liquid-liquid phase separator 110, so that the water content in the organic phase which flows back into the oxidation reactor 107 is low, the reaction conversion rate of the system of the oxidation reactor 107 is improved, and the energy consumption of the oxidation reactor 107 is saved to the greatest extent.

Specifically, pumps are arranged on the conveying pipelines of the wastewater and the organic phase and used for providing power for conveying the wastewater and the organic phase, the organic phase is liquid rich in dimethylbenzene, and the wastewater is liquid rich in water.

Specifically, the circulating liquid-liquid phase separator 110 further includes a tail gas port for discharging tail gas.

Referring to fig. 1, in one embodiment of the present utility model, the reflux apparatus further includes a recovery tank 101 and a recovery feed pump 111, both of which are disposed on a communication path of the circulating liquid-liquid phase separator 110 and the oxidation reactor 107.

In this embodiment, since the present system is a continuous reaction system, it is necessary to make the amount of the reaction material entering the oxidation reactor 107 within a predetermined range, so as to ensure that the time for the oxidation reaction of the reaction material in the oxidation reactor 107 is short, thereby realizing the continuity of production. The recovery storage tank 101 can temporarily store the organic phase produced by the circulating liquid-liquid phase separator 110, and convey the organic phase into the oxidation reactor 107 through the recovery feed pump 111 according to a predetermined flow rate, so as to ensure that the total amount of the organic phase and the reaction materials entering the oxidation reactor 107 is within a predetermined range, further ensure that the oxidation reactor 107 can be matched with the rectification subsystem, and realize the continuity of production.

Referring to fig. 1, in one embodiment of the present utility model, the rectification subsystem further includes a continuous concentrating device, the continuous concentrating device includes a continuous concentrator 201 and a concentrating and receiving tank 202, the heavy phase outlet of the gas-liquid separator 108 and the heavy phase outlet of the concentrating and receiving tank 202 are both in communication with the inlet of the continuous concentrator 201, the outlet of the continuous concentrator 201 is in communication with the inlet of the concentrating and receiving tank 202, and the heavy phase outlet of the concentrating and receiving tank 202 is also in communication with the inlet of the light component removal column 206.

In this embodiment, the continuous concentrator 201 performs reduced pressure concentration of the heavy phase component of the gas-liquid separator 108, and continues to evaporate unreacted components such as xylene, that is, the light phase component of the concentrating and receiving tank 202. The continuous concentrator 201 replaces a reaction kettle in the prior art, has high heat transfer efficiency, high concentration efficiency, stable concentration process and convenient operation, can automatically control continuous production, and can effectively save energy consumption compared with the reaction kettle.

Specifically, the continuous concentrator 201 is one or more of falling film concentration and thin film concentration. The operation temperature of the continuous concentrator 201 is 100-180 ℃, and the operation pressure is-0.07 MPa to-0.095 MPa.

Specifically, a pump is provided on a path in which the heavy phase outlet of the gas-liquid separator 108 communicates with the inlet of the continuous concentrator 201 to supply power to the continuous concentrator 201 for the heavy phase component of the gas-liquid separator 108, and a pump is also provided on a path in which the heavy phase outlet of the concentration receiving tank 202 communicates with the inlet of the continuous concentrator 201 to supply power to the continuous concentrator 201 for the heavy phase component of the concentration receiving tank 202. The gas-liquid separator 108 is connected to a connection pipe between the heavy phase outlet of the concentration receiving tank 202 and the inlet of the continuous concentrator 201, so that the heavy phase component of the gas-liquid separator 108 can be completely mixed with the heavy phase component of the concentration receiving tank 202 and then enter the continuous concentrator 201. A pump is also provided in the path of communication between the heavy phase outlet of the concentrate receiving tank 202 and the inlet of the light ends column 206 to provide the motive force for the heavy phase components of the concentrate receiving tank 202 to be delivered to the light ends column 206.

Referring to fig. 1, in one embodiment of the present utility model, the continuous concentrating apparatus further includes a concentrating condenser 203 and a concentrate-liquid phase separator 204, the light phase outlet of the concentrating receiving tank 202, the concentrating condenser 203 and the concentrate-liquid phase separator 204 are sequentially connected, and the organic phase outlet of the concentrate-liquid phase separator 204 is connected to the inlet of the oxidation reactor 107.

In this embodiment, the light phase component concentrated by the continuous concentrator 201 enters the concentrating condenser 203, is condensed by the concentrating condenser 203, enters the concentrated liquid-liquid phase separator 204, forms an organic phase and waste water after liquid-liquid phase separation, the organic phase flows back into the recovery storage tank 101, and enters the oxidation reactor 107 together with the organic phase produced by the circulating liquid-liquid phase separator 110, so that the unconcentrated and complete reaction material after passing through the continuous concentrator 201 can enter the oxidation reactor 107 again for oxidation reaction, the utilization rate of oxidized materials is improved for the second time, and the material loss is saved.

The primary improvement in the utilization ratio of the oxidized substance is achieved by the gas-liquid separator 108, the off-gas condenser 109, and the circulating liquid-liquid separator 110. The oxidized substances are the following mixed materials and compressed air.

Specifically, the concentrate liquid phase separator 204 further includes a gas phase outlet in communication with a concentrate vacuum pump 205.

Referring to fig. 1, in one embodiment of the present utility model, the reaction subsystem further includes a raw material storage tank 103, a catalyst storage tank 104, a batching device 105, and an air compressor 102, wherein the outlets of the raw material storage tank 103 and the catalyst storage tank 104 are respectively communicated with the inlet of the batching device 105, and the outlets of the air compressor 102 and the batching device 105 are respectively communicated with an oxidation reactor 107.

In this embodiment, the raw material storage tank 103 is used for storing fresh xylene raw materials, the catalyst storage tank 104 is used for storing catalysts, the batching device 105 is used for uniformly mixing the fresh xylene raw materials and the catalysts to form a mixed material, and the air compressor 102 is used for introducing compressed air into the oxidation reactor 107 according to a predetermined flow rate so as to enable the mixed material and the compressed air to react together. By the arrangement of the batching device 105, fresh dimethylbenzene raw materials and catalysts can be fully mixed before oxidation reaction, and the sufficiency and high efficiency of subsequent oxidation reaction are ensured.

Specifically, a pump is provided in the communication path between the raw material storage tank 103 and the dosing device 105 for supplying power to the dosing device 105 for fresh xylene raw material, and a pump is also provided in the communication path between the catalyst storage tank 104 and the dosing device 105 for supplying power to the catalyst to be supplied to the dosing device 105.

Specifically, the inlet of the oxidation reactor 107 is located at the bottom thereof.

Referring to FIG. 1, in one embodiment of the present utility model, the reaction subsystem further comprises a mixing tank 106, the mixing tank 106 being disposed in a communication path between the batching device 105 and the oxidation reactor 107.

In this embodiment, the mixed materials fully mixed by the batching device 105 firstly enter the mixing storage tank 106, a pump is further arranged on a communication path between the mixing storage tank 106 and the oxidation reactor 107, and the amount of the mixed materials conveyed into the oxidation reactor 107 can be controlled by the pump, so that on one hand, the amount of the reaction materials in the oxidation reactor 107 is ensured to be within a predetermined range, and on the other hand, when the batching time of the batching device 105 is shorter than the oxidation time of the oxidation reactor 107, the mixed materials in the batching device 105 can firstly enter the mixing storage tank 106 for temporary storage, so that a large amount of mixed materials are prevented from entering the oxidation reactor 107, and further, the continuous implementation can be ensured to be smoothly realized.

The oxidation reactor 107 has a gas-liquid mixing member (not shown in the figure), and the gas-liquid mixture inside the oxidation reactor 107 affects not only the mass transfer efficiency but also the gas-liquid reaction rate, so that the gas-liquid mixing member is provided, and after the mixture in the mixing tank 106 enters the oxidation reactor 107, the mixture is fully mixed by the gas-liquid mixing member, so that the amplification effect caused by poor liquid distribution is reduced, the gas-liquid mixing efficiency is fully exerted, the mass transfer effect is enhanced, and the reaction conversion rate is improved.

Specifically, a pump is provided in a communication path between the mixing tank 106 and the oxidation reactor 107, and is configured to introduce the mixed material in the mixing tank 106 into the oxidation reactor 107 at a predetermined flow rate.

In another embodiment, the real-time packing inside the oxidation reactor 107 is used to extend the retention time of the mixed materials inside the oxidation reactor 107 and enhance the mass and heat transfer inside the oxidation reactor 107, and the catalyst with a suitable particle size can also function as a packing. The oxidation reactor 107 is applicable to various gas-liquid reaction types and has high applicability.

The utility model is suitable for continuous production of three products of o-methylbenzoic acid, m-methylbenzoic acid and p-methylbenzoic acid, has wide application range, and can select one methylbenzoic acid for production according to requirements. The utility model is suitable for high-temperature oxidation reaction under normal pressure or high pressure, and is also suitable for gas-liquid reaction under other conditions. The continuous oxidation reactor 107 can strengthen mass transfer and heat transfer, effectively improve the single pass conversion rate and selectivity, and improve the overall yield by 3% -5%. By adopting the continuous system, the energy consumption is saved by 10% -20% compared with an intermittent system. Realize the full continuous flow of reaction and aftertreatment, degree of automation is high, and the simple operation promotes production efficiency, saves the cost of labor, accurate control.

By adopting the system, dimethylbenzene and a catalyst are uniformly mixed, the dosage of the catalyst is consistent with that of a batch, the mixed mixture is pumped into the oxidation reactor 107 by a pump, compressed air in the air compressor 102 is introduced from the bottom of the oxidation reactor 107, gas-liquid mixing and continuous reaction are completed in the oxidation reactor 107 at one time, the conversion rate of materials is improved by the oxidation reactor 107, compressed air is saved, the materials after the oxidation reaction are concentrated and pretreated by the gas-liquid separator 108, and then 30% -50% of recovery raw materials are collected, and the energy consumption is saved by nearly 20%; the heavy phase component of the gas-liquid separator 108 enters the continuous concentrator 201 to recycle the residual unreacted raw materials, the heavy phase component of the continuous concentrator 201 enters the light component removing tower 206 through a pump, continuous light component removing treatment is carried out according to the process operation parameters, the balance in the tower is established, the tower bottom of the light component removing tower 206 starts to continuously extract the liquid and transfers the liquid to the heavy component removing tower 302 to carry out the next heavy component removing treatment, and the qualified methylbenzoic acid product is separated from the tower top of the heavy component removing tower 302 after the balance of the components in the heavy component removing tower 302 is established according to the process operation parameters.

The following table shows actual feed comparison data for the preparation of meta-methylbenzoic acid from meta-xylene:

TABLE 1 actual feed comparison data for the preparation of Methylbenzoic acid from Meta-xylene

From the above description, it can be seen that the above-described embodiments of the present utility model achieve the following technical effects: the light component removing process and the heavy component removing process are respectively realized through the light component removing device and the heavy component removing device, so that the light component removing tower and the heavy component removing tower can work simultaneously, continuously produce the methylbenzoic acid and realize serialization. In addition, the light phase components produced by the light phase outlet of the light component removing tower need to be condensed and then returned to the light component removing tower for reaction, and in order to ensure the continuity, the reaction time of the light component removing tower needs to be ensured to be short only when the quantity of the reactant materials in the light component removing tower is within a preset range, therefore, a light component removing reflux tank and a light component removing control valve are arranged, the light phase components produced by the light component removing tower firstly enter the light component removing reflux tank for temporary storage, and the light phase components are gradually introduced into the light component removing tower through the light component removing control valve according to the requirement of the quantity of the reactant materials in the light component removing tower, so that the quantity of the reactant materials in the light component removing tower is always within the preset range, and the light component removing tower is ensured to realize continuous reaction; and in the same way, a weight-removing reflux tank and a weight-removing control valve are arranged, so that continuous reaction of the weight-removing tower can be realized. Through the arrangement of the weight removing device and the weight removing device, the production process of the methylbenzoic acid can realize continuity, the amount of materials entering the weight removing tower and the weight removing tower for single reaction is reduced, the reaction time is shortened, and the production efficiency is improved.

It will be apparent that the embodiments described above are merely some, but not all, embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (10)

1. A methylbenzoic acid production system comprising:

a reaction subsystem; and

a rectification subsystem in communication with the reaction subsystem, the rectification subsystem comprising:

the light component removing device comprises a light component removing tower (206), a light component removing condenser (207), a light component removing reflux tank (209) and a light component removing control valve (210), wherein the top of the light component removing tower (206), the light component removing condenser (207) and the light component removing reflux tank (209) are sequentially communicated and form a circulation loop, and the light component removing control valve (210) is arranged on a communication path of the light component removing reflux tank (209) and the light component removing tower (206) so as to control the quantity of materials which flow back to the light component removing tower (206); and

the heavy device that takes off, heavy device includes heavy tower (302) that takes off, heavy condenser (306), heavy reflux drum (305) and heavy control valve (307) that take off, the top of heavy tower (302) that takes off heavy condenser (306) with heavy reflux drum (305) communicate in proper order and form the circulation loop, heavy control valve (307) set up on the intercommunication route of heavy reflux drum (305) with heavy tower (302) that takes off, in order to control the backward flow to the quantity of the material of heavy tower (302) that takes off, the tower cauldron of light tower (206) with the entry intercommunication of heavy tower (302) that takes off.

2. The methylbenzoic acid production system according to claim 1, wherein the light component removing device further comprises a light component removing reflux pump (211), the light component removing reflux pump (211) being disposed on a communication path of the light component removing reflux tank (209) and the light component removing column (206); and/or the number of the groups of groups,

the weight removing device further comprises a weight removing reflux pump (308), and the weight removing reflux pump (308) is arranged on a communication path of the weight removing reflux tank (305) and the weight removing tower (302).

3. The methylbenzoic acid production system according to claim 1, wherein the light component removal device further comprises a light component removal extraction line (212), the light component removal extraction line (212) being communicated with a communication line between the light component removal reflux drum (209) and the light component removal column (206); and/or the number of the groups of groups,

the weight removing device further comprises a weight removing extraction pipeline (309), and the weight removing extraction pipeline (309) is communicated with a communicating pipeline between the weight removing reflux tank (305) and the weight removing tower (302).

4. A methylbenzoic acid production system according to any one of claims 1 to 3, characterized in that the reaction subsystem comprises an oxidation reactor (107) and a reflux device comprising a gas-liquid separator (108) and a tail gas condenser (109), the inlet of the gas-liquid separator (108) being in communication with the outlet of the oxidation reactor (107), the light phase outlet of the gas-liquid separator (108), the tail gas condenser (109) and the inlet of the oxidation reactor (107) being in turn in communication and forming a circulation loop.

5. The system according to claim 4, wherein the reflux device further comprises a circulating liquid-liquid phase separator (110), the circulating liquid-liquid phase separator (110) is disposed on a communication path between the off-gas condenser (109) and the oxidation reactor (107), an inlet of the circulating liquid-liquid phase separator (110) is communicated with an outlet of the off-gas condenser (109), and an organic phase outlet of the circulating liquid-liquid phase separator (110) is communicated with an inlet of the oxidation reactor (107).

6. The methylbenzoic acid production system according to claim 5, wherein the reflux device further comprises a recovery tank (101) and a recovery feed pump (111), both the recovery tank (101) and the recovery feed pump (111) being disposed on a communication path of the circulating liquid-liquid phase separator (110) and the oxidation reactor (107).

7. The methylbenzoic acid production system according to claim 4, wherein the rectification subsystem further comprises a continuous concentration device comprising a continuous concentrator (201) and a concentration receiving tank (202), wherein the heavy phase outlet of the gas-liquid separator (108) and the heavy phase outlet of the concentration receiving tank (202) are both in communication with the inlet of the continuous concentrator (201), the outlet of the continuous concentrator (201) is in communication with the inlet of the concentration receiving tank (202), and the heavy phase outlet of the concentration receiving tank (202) is also in communication with the inlet of the light component removal column (206).

8. The methylbenzoic acid production system according to claim 7, wherein the continuous concentrating device further comprises a concentrating condenser (203) and a concentrate liquid-liquid separator (204), the light phase outlet of the concentrating receiving tank (202), the concentrating condenser (203) and the concentrate liquid-liquid separator (204) are communicated in this order, and the organic phase outlet of the concentrate liquid-liquid separator (204) is communicated with the inlet of the oxidation reactor (107).

9. The methylbenzoic acid production system according to claim 4, wherein the reaction subsystem further comprises a raw material storage tank (103), a catalyst storage tank (104), a batching device (105) and an air compressor (102), wherein the outlets of the raw material storage tank (103) and the catalyst storage tank (104) are communicated with the inlet of the batching device (105), and the outlet of the air compressor (102) and the outlet of the batching device (105) are communicated with the oxidation reactor (107).

10. The methylbenzoic acid production system according to claim 9, wherein the reaction subsystem further comprises a mixing tank (106), the mixing tank (106) being disposed on a communication path of the dosing device (105) and the oxidation reactor (107).

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