CN111151201A

CN111151201A - Reaction device and system and method for synthesizing acetic acid by methanol carbonylation

Info

Publication number: CN111151201A
Application number: CN202010075008.XA
Authority: CN
Inventors: 陈大胜; 钱永明; 凌国珍; 朱平勇; 钟金华; 张雪峰; 陈楠
Original assignee: Shanghai Huayi Energy Chemical Co ltd
Current assignee: Shanghai Huayi Energy Chemical Co ltd
Priority date: 2020-01-22
Filing date: 2020-01-22
Publication date: 2020-05-15

Abstract

The invention provides a reaction device and a system and a method for synthesizing acetic acid by methanol carbonylation, wherein the reaction device comprises a reaction kettle and a fluid stirring part, the fluid stirring part comprises a reaction raw material distributor and a return pipe, the reaction kettle comprises a feed pipe, the reaction kettle is provided with a feed inlet, a return outlet and a return inlet, the reaction raw material distributor is arranged in the reaction kettle, the feed pipe penetrates through the feed inlet and is connected with the reaction raw material distributor, the return pipe penetrates through the return inlet, and the return outlet is connected with the return pipe. The reaction device is adopted to produce the acetic acid by methanol carbonylation, so that the phenomenon that a shaft seal and a bottom fixed bearing are easy to damage in the operation process during mechanical stirring is avoided, no dynamic sealing point exists in the whole reaction device, and the safe and stable operation of a reaction system is ensured; and meanwhile, the reactor is matched with a reaction raw material distributor, so that the raw materials in the reactor are distributed more uniformly, the gas-liquid two-phase mixing effect is improved, the reaction rate is increased, and the reaction state in the system is optimized.

Description

Reaction device and system and method for synthesizing acetic acid by methanol carbonylation

Technical Field

The invention belongs to the field of chemical industry, and relates to a reaction device, a system and a method for synthesizing acetic acid by methanol carbonylation.

Background

Acetic acid is an important chemical intermediate and solvent for chemical reactions. The most common acetic acid synthesis process used at present is the methanol low-pressure carbonyl synthesis process, which is initiated in the 70 s by Monsanto company in America, and has made a major breakthrough in device productivity, product quality and production cost after decades of innovation and development. In the aspect of process technology improvement, companies continuously seek new schemes, and it is described in patent CN 201525813 of hualu-changsheng chemical corporation that a methyl iodide circulating tower and an evaporator are arranged in front of a rectifying device to circulate methyl iodide in a reaction system, so that the amount of methyl iodide impurities mixed in acetic acid is reduced, and energy consumption required for purifying acetic acid is saved. The patent CN101665424 of Beijing Zehua chemical engineering Limited company describes that the functions executed by the existing lightness-removing tower and the existing dehydrating tower are combined in one rectifying tower, thereby simplifying the flow path of the preparation of acetic acid, reducing the equipment investment of the device, simultaneously reducing the difficulty of operation control, effectively reducing the energy consumption of the device and lowering the production cost.

At present, the technical improvement is mostly on a rectification system, the change of a reaction system is less, particularly, a reaction kettle unit still adopts a conventional mechanical stirring mode on gas-liquid stirring and mixing, and reaction equipment adopting mechanical stirring can effectively mix liquid-liquid and gas-liquid, but a shaft seal and a bearing required by mechanical transmission are extremely easy to damage in long-term operation, so that the shutdown maintenance is caused, and the continuous, stable and safe operation is difficult to realize. In recent years, gas-liquid stirring is an important direction for improving the technology of a methanol oxo acetic acid device, but the problems of poor gas-liquid mixing compared with the traditional mechanical stirring reaction device, reduced production capacity and the like exist.

Disclosure of Invention

In view of the technical problems in the prior art, the present invention aims to provide a reaction apparatus, a system and a method for methanol oxo-synthesis of acetic acid, wherein the reaction apparatus comprises a fluid stirring component, which replaces the situation that a mechanical stirring shaft seal and a bottom fixing bearing are easily damaged in the operation process, and eliminates a dynamic sealing point, thereby greatly improving the safety and stability. Meanwhile, the reactor is matched with a reaction raw material distributor, so that the distribution of reaction raw materials such as CO gas in the reactor is more uniform, the gas-liquid two-phase mixing effect is improved, the reaction rate is increased, and the reaction state is optimized.

The invention is realized by the following technical scheme:

the invention provides a reaction device, which comprises a reaction kettle and a fluid stirring part, wherein the fluid stirring part comprises a reaction raw material distributor and a return pipe, the reaction kettle comprises a feeding pipe, the reaction kettle is provided with a feeding hole, a return outlet and a return inlet, the reaction raw material distributor is arranged in the reaction kettle, the feeding pipe penetrates through the feeding hole and is connected with the reaction raw material distributor, the return pipe penetrates through the return inlet, and the return outlet is connected with the return pipe.

Preferably, the reaction kettle is further provided with a reaction liquid outlet for outputting the reaction liquid.

Preferably, a nozzle is arranged at the end part of the material returning pipe arranged in the reaction kettle.

More preferably, the spray head is of a reducing structure.

More preferably, the spray head is located below the liquid level of the reaction device, and the distance between the spray head and the return inlet is 1/5-1/2 of the height of the reaction kettle barrel, such as 1/5-2/5 or 2/5-1/2.

Preferably, the spray head is positioned in the middle of the reaction kettle.

Preferably, the feed inlet is arranged at the bottom of the reaction kettle.

Preferably, the return material outlet is arranged in the middle of the reaction kettle.

Preferably, the return material inlet is arranged at the top of the reaction kettle.

Preferably, the fluid stirring part further comprises a pump part and/or a cooling unit, and the return outlet is connected with the return pipe through the pump part and/or the cooling unit.

More preferably, the pump assembly comprises one or more pumps in parallel.

Preferably, the reaction raw material distributor is provided with air holes, the diameter of each air hole is 2-10 mm, and the distance between the air holes is 20-40 mm.

Preferably, the reaction raw material distributor is arranged at the bottom of the reaction kettle.

Preferably, the reaction raw material distributor is provided with an annular first distribution unit and a plurality of second distribution units, and the plurality of second distribution unit annular arrays are arranged on the annular first distribution unit.

The invention provides a system for synthesizing acetic acid by methanol carbonylation, which comprises the reaction device, a flash separator and a refining unit which are communicated in sequence.

Preferably, the flash separator is provided with a gas phase outlet and a liquid phase outlet, the gas phase outlet is communicated with the refining unit, and the liquid phase outlet is communicated with the reaction device.

The third aspect of the invention provides a method for synthesizing acetic acid by methanol carbonylation, which adopts the reaction device, and introduces reaction raw materials comprising methanol, CO and catalyst into the reaction device through the feeding pipe and the reaction raw material distributor in sequence, and adopts the fluid stirring component to stir the materials, and the materials react under the action of the catalyst to generate the acetic acid.

Preferably, the method further comprises the following steps: carrying out flash separation on the reaction liquid to respectively obtain a gas-phase material and a liquid-phase material; and refining the gas-phase material to obtain an acetic acid product, and refluxing the liquid-phase material to the reaction device.

Preferably, the flow speed of the reaction raw materials discharged from the reaction raw material distributor is 5-25 m/s.

Preferably, the flow velocity of the fluid sprayed by the spray head is 5-20 m/s.

Preferably, the fluid flow provided by the pump is 300-700 m³/h。

The reaction device comprises a fluid stirring part and a reaction raw material distributor, is used for producing the acetic acid by methanol oxo synthesis, avoids the phenomenon that a shaft seal and a bottom fixed bearing are easy to damage in the operation process in mechanical stirring, has no dynamic sealing point in the whole reaction device, eliminates the potential shutdown hazard possibly caused by mechanical seal leakage in the mechanical stirring and the replacement required by the failure of the stirring part in a kettle due to corrosion, ensures the safe and stable operation of a reaction system, and saves the expenditure of investment, operation and maintenance cost; meanwhile, the reaction kettle is matched with a reaction raw material distributor, the distribution of reaction raw materials such as CO gas and the like and circulating mother liquor is improved, particularly the gas-liquid mixing effect at the position close to the wall is improved, the gas-liquid phase in the reaction kettle is fully mixed, the reaction speed is improved, the reaction state in the system is optimized, and therefore the productivity is improved.

Drawings

FIG. 1 is a schematic view of the structure of the upper part of a reaction apparatus.

FIG. 2 is a schematic view of the structure of the bottom of the reaction apparatus.

FIG. 3 is a schematic diagram of a reaction material distributor.

FIG. 4 is a schematic view of the overall structure of the reaction apparatus.

FIG. 5 shows a system for synthesizing acetic acid by methanol carbonylation.

Reference numerals

1 reaction apparatus

11 reaction kettle

1111 feed pipe

1112 feed inlet

1122 return outlet

1123 return material inlet

12 fluid agitating member

121 reaction raw material distributor

1211 air vent

1212 annular first distribution unit

1213 second distribution unit

122 return pipe

1221 spray head

123 pump component

1231 pump

124 cooling unit

2 flash separator

21 gas phase outlet

22 liquid phase outlet

3 refining unit

Detailed Description

The technical solution of the present invention is illustrated by specific examples below. It is to be understood that one or more method steps mentioned in the present invention do not exclude the presence of other method steps before or after the combination step or that other method steps may be inserted between the explicitly mentioned steps; it should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Moreover, unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention in which the invention may be practiced, and changes or modifications in the relative relationship may be made without substantially changing the technical content.

A reaction device, as shown in fig. 1, fig. 2 and fig. 4, comprising a reaction vessel 11 and a fluid stirring component 12, wherein the fluid stirring component 12 includes a reaction raw material distributor 121 and a return pipe 122, the reaction vessel 11 includes a feeding pipe 1111, the reaction vessel 11 is provided with a feeding port 1112, a return outlet 1122 and a return inlet 1123, the reaction raw material distributor 121 is disposed in the reaction vessel 11, the feeding pipe 1111 penetrates through the feeding port 1112 and is connected to the reaction raw material distributor 121, the return pipe 122 penetrates through the return inlet 1123, and the return outlet 1122 is connected to the return pipe 122.

The reaction device is adopted to produce the acetic acid by methanol carbonylation, so that the phenomenon that a shaft seal and a bottom fixed bearing are easy to damage in the operation process during mechanical stirring is avoided, no dynamic sealing point exists in the whole reaction device, and the safe and stable operation of a reaction system is ensured; and meanwhile, the reactor is matched with a reaction raw material distributor, so that the raw materials in the reactor are distributed more uniformly, the gas-liquid two-phase mixing effect is improved, the reaction rate is increased, and the reaction state in the system is optimized.

In a preferred embodiment, the reaction vessel 11 is further provided with a reaction liquid outlet for outputting the reaction liquid.

In a preferred embodiment, a spray nozzle 1221 is disposed at the end of the return pipe 122 disposed in the reaction vessel 11. The nozzle 1221 is preferably of a reducing structure, so that the injection speed of the circulating reaction liquid can be obviously increased, and the degree of gas-liquid mixing can be improved.

In a preferred implementation, the spray nozzle 1221 is positioned below the liquid level of the reaction device, and the distance between the spray nozzle 1221 and the return material inlet 1123 is 1/5-1/2 of the height of the reaction kettle barrel.

In a preferred embodiment, the flow rate of the reaction material exiting the reaction material distributor may be 5 to 25 m/s.

In a preferred embodiment, the flow rate of the fluid sprayed from the spray head may be 5 to 20 m/s.

In a preferred embodiment, the nozzle 1221 is preferably located in the middle of the inside of the reaction vessel 11.

In a preferred embodiment, the feed port 1112 is preferably disposed at the bottom of the reaction vessel 11.

In a preferred embodiment, the return outlet 1122 is provided in the middle of the reaction vessel 11.

In a preferred embodiment, the return feed inlet 1123 is located at the top of the reaction vessel 11. The reaction liquid flows down from a high position, so that higher speed can be provided, and better stirring effect can be generated.

In a preferred embodiment, the fluid stirring unit 12 further includes a pump unit 123 and/or a cooling unit 124, and the return outlet 1122 is connected to the return pipe 122 via the pump unit 123 and/or the cooling unit 124. The reaction liquid is transported to the next unit under the power of the pump component. The cooling unit is used for cooling the reaction liquid.

The reaction liquid in the reaction device flows out from a return outlet 1122, the return outlet 1122 is arranged in the middle of the reaction kettle 11, and can be conveyed to the cooling unit 124 for cooling under the power action of the pump part 123 and then conveyed to the return inlet 1123, the reaction liquid flows downwards at a high speed along the return pipe 122 and is sprayed out by the spray head 1221, the peripheral liquid is driven to change the vector, and the reaction liquid is turned over from the kettle bottom of the reaction device to form different circulating flow states of a plurality of main flow layers.

In a preferred implementation, the pump assembly 123 includes one or more pumps 1231 in parallel. For example, the pump components may be two pumps connected in parallel, as shown in fig. 5, which can satisfy the requirement of sufficient gas-liquid two-phase mixing in a large-volume reaction device. The flow rate of the fluid provided by the pump can be 300-700 m³H, e.g. 300 to 530m³H or 530 to 700m³/h。

In a preferred embodiment, the reaction material distributor 121 is provided with air holes 1211, the diameter of the air holes 1211 is 2 to 10mm, and the distance between the air holes is 20 to 40 mm. No dead angle is left in the plane area of the reaction device, the whole reaction device presents the ascending trend of operation, and the reaction raw materials in the space of the whole reaction device are uniformly distributed along with the coalescence and separation of bubbles. The flow rate of the reaction raw material out of the reaction raw material distributor may be 5 to 25 m/s.

In a preferred embodiment, the reactant material distributor 121 is disposed at the bottom of the reaction vessel 11.

In a preferred embodiment, as shown in fig. 3, the reactant material distributor 121 is provided with an annular first distribution unit 1212 and a plurality of second distribution units 1213, the plurality of second distribution units 1213 being arranged in an annular array on the annular first distribution unit 1212. The reaction raw material distributor is convenient for the distribution of the reaction raw materials on the whole cross section of the reaction device, is suitable for a large-diameter reactor, simultaneously ensures the uniform distribution of the reaction raw materials in the vertical direction, especially ensures the full reaction of the upper reaction liquid under the condition of weakened stirring of the fluid, and improves the gas-liquid two-phase mixing reaction effect.

A system for synthesizing acetic acid by methanol carbonylation, as shown in figure 5, comprises the reaction device 1, a flash separator 2 and a refining unit 3 which are communicated in sequence.

In a preferred embodiment, the flash separator 2 is provided with a gas phase outlet 21 and a liquid phase outlet 22, the gas phase outlet 21 being in communication with the refining unit 3 and the liquid phase outlet 22 being in communication with the reaction device 1.

Comparative example

The industrial equipment for synthesizing acetic acid by using methyl alcohol carbonyl adopts mechanical stirring device and ring-type pipe body CO distributor before the reactor is reformed, and on the distributor there is no straight pipe section, and the material-returning mouth is positioned above the liquid level and has no reducing diameter. Under certain temperature and pressure and in the presence of catalyst, methanol and CO produce carbonylation reaction to produce acetic acid.

Example 1

In the industrial device for synthesizing acetic acid by methanol carbonylation, after a reactor is transformed, the fluid stirring component shown in figures 1 and 2 and the reaction raw material distributor shown in figure 3 (an annular first distribution unit and 5 second distribution units, wherein 5 second distribution unit ring-shaped arrays are arranged on the annular first distribution unit) are adopted, the spray nozzle 1221 is positioned below the liquid level of the reaction device, and the distance between the spray nozzle 1221 and the return material inlet 1123 is 1/3 of the height of the cylinder of the reaction kettle. Under the conditions of certain temperature and pressure and the existence of a catalyst, methanol and CO are subjected to carbonylation reaction to generate acetic acid, and the outlet flow of a material returning circulating pump is 300m³The productivity was increased by 10% compared to the comparative example (as shown in FIG. 5).

Example 2

In the industrial device for synthesizing acetic acid by methanol carbonylation, after the reactor is reformed, the fluid stirring part shown in figure 1 and figure 2 and the reaction raw material distributor (an annular first distribution unit and 8 second distribution units, 8 second distribution units are arranged in an annular first distribution unit annular array) shown in figure 3 are adoptedOn the distribution unit), the spray head 1221 is positioned below the liquid level of the reaction device, and the distance between the spray head 1221 and the return material inlet 1123 is 1/2 of the height of the reaction kettle barrel. Under the conditions of certain temperature and pressure and the existence of a catalyst, methanol and CO are subjected to carbonylation reaction to generate acetic acid, and the outlet flow of a material returning circulating pump is 700m³The productivity is improved by 20 percent compared with the comparative example

Example 3

In the industrial device for synthesizing acetic acid by methanol carbonylation, after a reactor is transformed, the fluid stirring component shown in figures 1 and 2 and the reaction raw material distributor shown in figure 3 (an annular first distribution unit and 4 second distribution units, wherein 4 second distribution unit ring arrays are arranged on the annular first distribution unit) are adopted, the spray nozzle 1221 is positioned below the liquid level of the reaction device, and the distance between the spray nozzle 1221 and the material returning inlet 1123 is 1/5 of the height of the cylinder of the reaction kettle. Under the conditions of certain temperature and pressure and the existence of a catalyst, methanol and CO are subjected to carbonylation reaction to generate acetic acid, and the outlet flow of a material returning circulating pump is 530m³And h, the productivity is improved by 15 percent compared with that of the comparative example.

While the invention has been described with respect to a preferred embodiment, it will be understood by those skilled in the art that the foregoing and other changes, omissions and deviations in the form and detail thereof may be made without departing from the scope of this invention. Those skilled in the art can make various changes, modifications and equivalent arrangements, which are equivalent to the embodiments of the present invention, without departing from the spirit and scope of the present invention, and which may be made by utilizing the techniques disclosed above; meanwhile, any changes, modifications and variations of the above-described embodiments, which are equivalent to those of the technical spirit of the present invention, are within the scope of the technical solution of the present invention.

Claims

1. The utility model provides a reaction unit, characterized in that, includes reation kettle (11) and fluid mixing part (12), fluid mixing part (12) are including reaction raw material distributor (121) and returning charge pipe (122), reation kettle (11) include inlet pipe (1111), reation kettle (11) are equipped with feed inlet (1112), returning charge export (1122) and returning charge import (1123), reaction raw material distributor (121) are located in reation kettle (11), inlet pipe (1111) run through feed inlet (1112) and with reaction raw material distributor (121) are connected, returning charge pipe (122) run through returning charge import (1123), returning charge export (1122) with returning charge pipe (122) are connected.

2. The reactor device according to claim 1, characterized in that it further comprises at least one of the following technical features:

1) the reaction kettle (11) is also provided with a reaction liquid outlet for outputting reaction liquid;

2) a spray head (1221) is arranged at the end part of the return pipe (122) arranged in the reaction kettle (11);

3) the spray head (1221) is positioned in the middle of the inside of the reaction kettle (11);

4) the feed inlet (1112) is arranged at the bottom of the reaction kettle (11);

5) the return outlet (1122) is arranged in the middle of the reaction kettle (11);

6) the material returning inlet (1123) is arranged at the top of the reaction kettle (11);

7) the fluid stirring part (12) further comprises a pump part (123) and/or a cooling unit (124), and the return material outlet (1122) is connected with the return pipe (122) through the pump part (123) and/or the cooling unit (124);

8) the reaction raw material distributor (121) is arranged at the bottom of the reaction kettle (11).

3. The reactor according to claim 2, characterized in that in feature 2) at least one of the following technical features is also included:

1) the spray head (1221) is of a reducing structure;

2) the spray head (1221) is located below the liquid level of the reaction device, and the distance between the spray head (1221) and the return material inlet (1123) is 1/5-1/2 of the height of the reaction kettle barrel.

4. A reactor device as claimed in claim 2, characterized in that, in feature 7), the pump means (123) comprise one or more pumps (1231) connected in parallel.

5. The reaction apparatus according to claim 1, wherein the reaction material distributor (121) is provided with air holes (1211), the diameter of the air holes (1211) is 2 to 10mm, and the distance between the air holes is 20 to 40 mm.

6. The reaction apparatus according to claim 1, wherein the reaction raw material distributor (121) is provided with an annular first distribution unit (1212) and a plurality of second distribution units (1213), the plurality of second distribution units (1213) being arranged in an annular array on the annular first distribution unit (1212).

7. A system for methanol oxo-synthesis of acetic acid, characterized by comprising a reaction apparatus (1) according to any one of claims 1 to 6, a flash separator (2) and a refining unit (3) in sequential communication.

8. A system for methanol oxo-acetic acid according to claim 7, wherein the flash separator (2) is provided with a gas phase outlet (21) and a liquid phase outlet (22), the gas phase outlet (21) being in communication with the refining unit (3) and the liquid phase outlet (22) being in communication with the reaction unit (1).

9. A method for synthesizing acetic acid by methanol carbonylation is characterized in that a reaction device of any one of claims 1 to 6 is adopted, reaction raw materials comprising methanol, CO and a catalyst are introduced into the reaction device through the feeding pipe and the reaction raw material distributor in sequence, the materials are stirred by the fluid stirring component, and the materials react under the action of the catalyst to generate the acetic acid.

10. The method of methanol oxo acetic acid according to claim 9, further comprising at least one of the following technical features:

1) also comprises the following steps: carrying out flash separation on the reaction liquid to respectively obtain a gas-phase material and a liquid-phase material; refining the gas-phase material to obtain an acetic acid product, and refluxing the liquid-phase material to the reaction device;

2) the flow speed of the reaction raw materials out of the reaction raw material distributor is 5-25 m/s;

3) the flow velocity of the fluid sprayed by the spray head is 5-20 m/s;

4) the flow rate of the fluid provided by the pump is 300-700 m³/h。