Separation system suitable for low-pressure carbonyl synthesis of acetic acid

Abstract

In order to overcome the defects in the prior art, the utility model provides a separation system suitable for low-pressure carbonyl synthesis of acetic acid, the separation system comprises a reaction kettle, a light component removal tower and an evaporation system connected with the reaction kettle and the light component removal tower, the evaporation system comprises a primary evaporator and a secondary evaporator, a tower top outlet end of the light component removal tower is communicated with the reaction kettle, and a tower top outlet end of the secondary evaporator is communicated with the reaction kettle. And the inlet end is communicated with the gas phase outlet end of the second-stage evaporator. And the liquid phase outlet end of the secondary evaporator is communicated with the reaction kettle. And the inlet end of the second-stage evaporator is communicated with the liquid phase outlet end of the first-stage evaporator. And the gas phase outlet end of the first-stage evaporator is communicated with the reaction kettle. The inlet end of the first-stage evaporator is communicated with the reaction liquid outlet end of the reaction kettle. According to the utility model, the problems of large separation load, large heat and cold loss and large layering difficulty of the light component removal tower caused by the fact that a large amount of light components enter a low-pressure system after flash evaporation in the prior art are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of separation and recovery, in particular to a separation system suitable for low-pressure carbonyl synthesis of acetic acid. Background Art

[0002] At present, low-pressure carbonyl synthesis is the most important industrial production technology of acetic acid, which is favored by production enterprises. Among them, carbonyl synthesis reaction and separation are the key to carbonyl synthesis of acetic acid. Raw materials methanol and carbon monoxide enter the reactor and react to generate acetic acid under the action of a certain temperature and pressure catalyst. The reaction liquid enters the evaporator after passing through the pressure reducing valve, and flash separation is carried out in the evaporator. The gas phase of the evaporator enters the light-removing tower to remove the light components, and the liquid phase is pressurized by the catalyst circulation pump and returned to the reactor for recycling. Due to the high boiling point of acetic acid, the pressure of the evaporation system needs to be reduced to about 0.08MPa. At this pressure, about 10-25% of the light components in the reaction liquid enter the light-removing tower. Therefore, a three-stage condenser needs to be set at the top of the light-removing tower: a primary cooler, a final cooler and an aftercooler, and enters the stratifier after three-stage condensation. The light phase partly refluxes to the light-removing tower, and partly returns to the reactor through a high-speed pump, and the heavy phase returns to the reactor after being pressurized by a high-speed pump. A large amount of light components enter the lightness-removing tower and need the tower kettle to add steam to purify to the tower top and recycle through three-stage condenser condensation, causing steam consumption and circulating water consumption to be high. In addition, because the boiling point of the methyl iodide of low pressure is lower and one of the catalysts is lower, even if the content of methyl iodide in the gas phase is still higher after three-stage condensation, it is necessary to absorb and desorb by the absorption section, causing the loss of iodine and wasting steam and circulating water. As can be seen, the separation system of the existing low-pressure carbonyl synthesis of acetic acid not only consumes steam, circulating water and low-temperature water on the high side, and the excessive consumption of iodine caused by the circulation circle of iodine is high. Utility Model Content

[0003] In order to solve the deficiencies of the prior art, the utility model provides a separation system suitable for low-pressure carbonyl synthesis of acetic acid, comprising a reactor, a light removal tower and an evaporation system connecting the reactor and the light removal tower, wherein:

[0004] The top outlet of the light removal tower is connected to an inlet of the reaction kettle through a first connecting pipe, and the inlet is connected to the gas phase outlet of the secondary evaporator through a second connecting pipe.

[0005] The liquid phase outlet of the secondary evaporator is connected to a liquid phase material inlet of the reactor through a fourth connecting pipe. The inlet of the secondary evaporator is connected to the liquid phase outlet of the primary evaporator through a third connecting pipe.

[0006] The gas phase outlet end of the primary evaporator is connected to the other inlet end of the reactor through the sixth connecting pipe. The inlet end of the primary evaporator is connected to the reaction liquid outlet end of the reactor through the fifth connecting pipe.

[0007] The fourth connecting pipe, the third connecting pipe, the fifth connecting pipe and the sixth connecting pipe are respectively equipped with adjustment mechanisms.

[0008] Furthermore, the primary evaporator and the secondary evaporator have the same structure, both comprising: a cylindrical chamber with a wider top and a triangular cone-shaped chamber at the bottom that are interconnected, an evaporation tube is provided in the cylindrical chamber at the bottom near the top of the triangular cone-shaped chamber, and the inlet end of the evaporation tube extends to the outside of the cylindrical chamber as the inlet end of the evaporator. An exhaust pipe is provided at the top of the cylindrical chamber, and one end of the exhaust pipe extends to the outside of the cylindrical chamber as the gas phase outlet end of the evaporator. A liquid phase outlet end controlled by a drainage mechanism is provided at the bottom of the triangular cone-shaped chamber at the top of the triangular cone.

[0009] Furthermore, the outer wall of the cylindrical chamber is provided with an ear seat above the evaporation tube.

[0010] Furthermore, a trumpet-shaped collector is provided on the side of the exhaust pipe facing the evaporation pipe, and a demister covering the cross section of the collector is provided on the collector.

[0011] Furthermore, the fourth connecting pipe is connected to the inlet end of the first pressurizing device, and the outlet end of the first pressurizing device is connected to a liquid phase material inlet end of the reactor through the eighth connecting pipe. At this time, the regulating mechanism originally arranged on the fourth connecting pipe is changed to be arranged on the eighth connecting pipe.

[0012] Furthermore, the sixth connecting pipe is connected to the inlet end of the second pressurizing device, and the outlet end of the second pressurizing device is connected to the other inlet end of the reactor through the seventh connecting pipe.

[0013] Furthermore, the first connecting pipe is connected to the inlet end of the third pressurizing device, and the outlet end of the third pressurizing device is connected to the inlet end of the reactor through a ninth connecting pipe.

[0014] Furthermore, a base is movably mounted on the lower surface of the first-stage evaporator and the second-stage evaporator, a plurality of damping rods are fixedly connected to the upper surface of the base, a support plate is fixedly connected to the upper surface of the damping rod, and a damping spring is fixedly connected between the lower surface of the support plate and the upper surface of the base.

[0015] Furthermore, the secondary evaporator, the third connecting pipe, the fourth connecting pipe, and the eighth connecting pipe are all connected to a carbon monoxide supply system. The carbon monoxide supply system supplies carbon monoxide gas to the secondary evaporator, the third connecting pipe, the fourth connecting pipe, and the eighth connecting pipe.

[0016] The utility model has at least the following beneficial effects:

[0017] (1) The utility model changes the traditional acetic acid separation process and adopts a new energy-saving process to solve the problems in the existing process that a large amount of light components enter the low-pressure system after flash evaporation, the separation load of the light-removal tower is large, the heat and cold loss is large, and the stratification is difficult.

[0018] (2) The process of the utility model is that the light component circulates in the high-pressure circle, taking away less reaction heat. The remaining reaction heat can produce more steam as a by-product, and the by-product steam can be used in a cascade manner, thereby achieving the purpose of reducing system energy consumption and saving energy.

[0019] (3) In the present invention, most of the light components, especially methyl iodide, are directly returned to the reactor after the first-stage flash evaporation, and a very small amount enters the top of the light removal tower. After condensation, only a small amount of methyl iodide enters the absorption system, and the amount of absorbent is reduced. At the same time, the steam and circulating water consumption of the absorption system is reduced, and the small circulation loop process is adopted to significantly reduce the consumption of iodine. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the overall structure of the separation system of the utility model suitable for low-pressure carbonyl synthesis of acetic acid;

[0021] Figure 2 It is another side view of the overall structure schematic diagram of the separation system of the utility model suitable for low-pressure carbonyl synthesis of acetic acid;

[0022] Figure 3 It is a three-dimensional structural diagram of the base and its related structures of the utility model;

[0023] Figure 4 This is a schematic diagram of the structure of the evaporator of the utility model.

[0024] In the figure: 1, light-removal tower; 2, first connecting pipe; 3, second connecting pipe; 4, secondary evaporator; 5, third connecting pipe; 6, fourth connecting pipe; 7, primary evaporator; 8, fifth connecting pipe; 9, sixth connecting pipe; 10, second pressurizing device; 11, seventh connecting pipe; 12, reactor; 13, eighth connecting pipe; 14, first pressurizing device; 15, regulating mechanism; 16, base; 17, damping rod; 18, support plate; 19, damping spring; 20, third pressurizing device; 21, ninth connecting pipe. DETAILED DESCRIPTION

[0025] Now the utility model is further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the components related to the utility model.

[0026] Please note that the terms "above", "below", "left", "right", "top", "top", "bottom", "bottom", etc. used in the present invention to describe the positional relationship do not represent the absolute positional relationship between the modules / components / assemblies / components / parts, but the relative positional relationship between the modules / components / assemblies / components / parts.

[0027] The utility model exemplarily provides a separation system suitable for low-pressure carbonyl synthesis of acetic acid, such as Figure 1 and Figure 2 As shown, it includes a reactor 12, a light-removal tower 1, and an evaporation system connecting the reactor 12 and the light-removal tower 1, wherein the evaporation system includes: a primary evaporator 7 and a secondary evaporator 4, wherein:

[0028] The outlet end of the light removal tower 1 is connected to an inlet end of the reaction kettle 12 through a first connecting pipe 2 , and the inlet end is connected to the gas phase outlet end of the secondary evaporator 4 through a second connecting pipe 3 .

[0029] The liquid phase outlet of the secondary evaporator 4 is connected to a liquid phase material inlet of the reactor 12 through the fourth connecting pipe 6. The inlet of the secondary evaporator 4 is connected to the liquid phase outlet of the primary evaporator 7 through the third connecting pipe 5.

[0030] The gas phase outlet end of the primary evaporator 7 is connected to the other inlet end of the reaction kettle 12 through the sixth connecting pipe 9. The inlet end of the primary evaporator 7 is connected to the reaction liquid outlet end of the reaction kettle 12 through the fifth connecting pipe 8.

[0031] The fourth connecting pipe 6, the third connecting pipe 5, the fifth connecting pipe 8 and the sixth connecting pipe 9 are respectively provided with an adjusting mechanism 15. The adjusting mechanism 15 may be a pressure reducing valve, a regulating valve or the like as required.

[0032] Compared with the prior art, the utility model improves the evaporation system. At this time, the reaction liquid in the reactor 12 enters the primary evaporator 7 for primary flash evaporation, and 40-95% of light components such as methyl iodide and methyl acetate and a small amount of water and acetic acid are separated, and the separated gas phase returns to the reactor 12 for recycling.

[0033] The secondary evaporator 4 is at the same pressure level as the light-removal tower 1. The discharge from the primary evaporator 7 enters the secondary evaporator 4. The remaining 5-60% of light components such as methyl iodide and methyl acetate and a large amount of acetic acid and water are separated by further reduced-pressure flash evaporation. The gas-liquid mixture enters the light-removal tower 1, and the remaining mother liquor containing the catalyst is returned to the reactor 12 for recycling.

[0034] The utility model exemplarily provides a pipeline connection method, such as Figure 1 and Figure 2As shown, it includes: the fourth connecting pipe 6 is connected to the inlet end of the first pressurizing device 14, and the outlet end of the first pressurizing device 14 is connected to a liquid phase material inlet end of the reactor 12 through the eighth connecting pipe 13. At this time, the regulating mechanism 15 originally arranged on the fourth connecting pipe 6 is changed to be arranged on the eighth connecting pipe 13. Since a certain reaction pressure needs to be set in the reactor 12, the additional first pressurizing device 14 can be used to adjust the pressure of the mother liquid transported from the secondary evaporator 4 to the reactor 12, which can increase the transport efficiency on the one hand, and prevent the liquid phase components in the reactor 12 from flowing back to the secondary evaporator 4 on the other hand.

[0035] The present invention exemplarily provides a first pressurizing device 14 which is a circulation pump, specifically a mother liquid circulation pump.

[0036] The utility model exemplarily provides a pipeline connection method, such as Figure 1 and Figure 2 As shown, it includes: the sixth connecting pipe 9 is connected to the inlet end of the second pressurizing device 10, and the outlet end of the second pressurizing device 10 is connected to the other inlet end of the reactor 12 through the seventh connecting pipe 11. Since a certain reaction pressure needs to be set in the reactor 12, the additional second pressurizing device 10 can be used to adjust the pressure of the gas phase component transported from the primary evaporator 7 to the reactor 12, which can increase the transport efficiency on the one hand, and prevent the gas phase component in the reactor 12 from flowing back to the primary evaporator 7 on the other hand.

[0037] The present invention exemplarily provides a second pressurizing device 10 which is a compressor.

[0038] The working principle of the above mechanism is that when the low-pressure carbonyl synthesis acetic acid separation work is carried out, the reaction liquid enters the first-stage flash evaporation through the pressure reducing valve 15, and 40-95% of the light components such as methyl iodide and methyl acetate and a small amount of water and acetic acid are separated. The separated gas phase is pressurized by the compressor and returned to the reactor 12 for recycling. The pressure of the primary flash evaporation is adjusted by controlling the compressor outlet pressure, and the liquid level of the primary evaporator 7 is controlled by the discharge regulating valve. The discharge of the primary evaporator 7 enters the secondary evaporator 4 through the third connecting pipe 5 after passing through the pressure reducing valve 15. The pressure of the secondary evaporator 4 is controlled between 0.03-0.3MPaG. The remaining 5-60% of light components such as methyl iodide and methyl acetate and a large amount of acetic acid and water are separated by further reduced pressure flash evaporation. The gas-liquid mixture enters the light-removing tower 1 through the second connecting pipe 3. The remaining mother liquor containing the catalyst is returned to the reactor 12 from the eighth connecting pipe 13 through the fourth connecting pipe 6 through the first catalyst pressurizing device 14 for recycling. The secondary evaporator 4 is at the same pressure level as the light-removing tower 1 and the low-pressure absorption tower. The pressure of the secondary evaporator 4 is controlled by the pressure of the low-pressure absorption tower, and the liquid level of the secondary evaporator 4 is controlled by the outlet flow of the catalyst circulation pump. In order to maintain the stability of the catalyst, carbon monoxide is introduced into the secondary evaporator 4, and a relatively high carbon monoxide partial pressure is controlled to protect the catalyst and reduce the loss of the catalyst. The reactor 12 controls a certain temperature and pressure to generate acetic acid through carbon monoxide, methanol and various auxiliary materials returned from the rear system under the action of the catalyst, and the eighth connecting pipe 13 and the first connecting pipe 2 are used in conjunction with the seventh connecting pipe 11. The primary evaporator 7 uses part of the reaction heat to reduce the pressure and separates 40-95% of the light components such as methyl iodide and methyl acetate in the reaction liquid and a small amount of water and acetic acid in the primary evaporator 7. The gas phase of the primary evaporator 7 is pressurized by the second pressurizing device 10 in conjunction with the sixth connecting pipe 9. The separated light components are returned to the reactor 12 through the seventh connecting pipe 11. In addition, the pressure control of the primary evaporator 7 is realized through the outlet or reflux. The secondary evaporator 4 separates a small amount of methyl iodide, methyl acetate and a large amount of acetic acid and water in the liquid phase of the primary evaporator 7 by further reducing the pressure. The gas-liquid mixture at the top of the secondary evaporator 4 enters the light removal tower 1, and the liquid phase returns to the reactor 12 through the catalyst circulation pump. The first pressurizing device 14 provides power to send the discharge of the secondary evaporator 4 back to the reactor 12 to realize the recycling of the catalyst. The light removal tower 1 purifies the light components and part of the water and acetic acid to the top of the tower, and returns to the reactor 12 for recycling after the primary or secondary condensation through the first connecting pipe 2.

[0039] Compared with the existing acetic acid production system, the utility model innovates the classic process of the acetic acid industry, mainly in that: according to the characteristics of large difference in boiling points between methyl iodide, methyl acetate, acetic acid and water, the utility model changes the reaction liquid from one-stage separation to multi-stage flash separation. The utility model separates 40-95% of light components such as methyl iodide and methyl acetate and a small amount of water and acetic acid through one-stage separation and directly returns them to the reactor, instead of sending 40-95% of light components such as methyl iodide and methyl acetate into a light removal tower to be steamed to the top of the tower, and then sent into the reactor by a high-speed pump after three-stage condensation, and the light components are returned to the reactor after a large cycle, resulting in repeated waste of energy.

[0040] After two-stage flash evaporation, almost all light components return to the reactor, and only a small amount of light components enter the light-removing tower. The separation load of the light-removing tower is reduced. Not only the steam in the tower reboiler will be reduced, but also the load of the top condenser will be reduced. Multi-stage condensation and stratification are not required. Therefore, the amount of desalted water added to the top reflux tank will be reduced (only the water consumed by the water vaporization reaction needs to be added), and the load of the dehydration tower will be reduced accordingly. The classical process requires the installation of high-speed pumps for returning the light phase and the heavy phase at the same time. The utility model only needs to install one high-speed pump, and the one-time investment and maintenance costs of static equipment will be reduced. In addition, the allowable fluctuation range of the temperature of the sensitive plate of the light-removing tower is increased, and the difficulty of operation is greatly reduced.

[0041] In addition, the utility model also reduces the circulation loop of light components, reduces iodine consumption and reduces absorption load. In the classic process, a large amount of light components enter the low-pressure system. Even if the light-removing tower is provided with three-stage condensation, some methyl iodide still enters the absorption system with the low-pressure venting air. Therefore, it is necessary to add a large amount of absorbent to recover the methyl iodide in the venting air and then return to the reactor. The larger the circulation loop, the higher the energy consumption and the greater the loss. The utility model solves this problem well. Most of the light components, especially methyl iodide, directly return to the reactor after the first-stage flash evaporation, and a very small amount enters the top of the light-removing tower. After condensation, only a trace amount of methyl iodide enters the absorption system, and the amount of absorbent is reduced, while reducing the steam and circulating water consumption of the absorption system. The most important thing is that the small circulation loop process is adopted to greatly reduce the consumption of iodine.

[0042] The utility model exemplarily provides a pipeline connection method, such as Figure 1 and Figure 2 As shown, the first connecting pipe 2 is connected to the inlet end of the third pressurizing device 20, and the outlet end of the third pressurizing device 20 is connected to the other inlet end of the reactor 12 through the ninth connecting pipe 21. Since a certain reaction pressure needs to be set in the reactor 12, the additional third pressurizing device 20 can be used to adjust the pressure of the material transported from the lightness removal tower 1 to the reactor 12, which can increase the transport efficiency on the one hand, and prevent the material in the reactor 12 from flowing back to the lightness removal tower 1 on the other hand.

[0043] The present invention exemplarily provides a third pressurizing device 20 which is a pump or a compressor.

[0044] The utility model exemplarily provides a primary evaporator 7 and a secondary evaporator 4, wherein the primary evaporator 7 and the secondary evaporator 4 have the same structure, such as Figure 4 As shown, they all include: a cylindrical chamber with a wider top and a triangular cone-shaped chamber at the bottom that are interconnected, an evaporation tube is provided in the cylindrical chamber at the bottom near the top of the triangular cone-shaped chamber, and the inlet end of the evaporation tube extends to the outside of the cylindrical chamber as the inlet end of the evaporator. An exhaust pipe is provided at the top of the cylindrical chamber, and one end of the exhaust pipe extends to the outside of the cylindrical chamber as the gas phase outlet end of the evaporator. A liquid phase outlet end controlled by a drainage mechanism is provided at the bottom of the triangular cone-shaped chamber at the top of the triangular cone. This evaporator can realize the flash evaporation process of the utility model with very few steps.

[0045] The utility model exemplarily provides an evaporator, such as Figure 4 As shown, the evaporator is provided with an ear seat on the outer wall of the cylindrical chamber above the evaporation tube. Due to the special structure of the generator, the added ear seat mechanism allows the evaporator to be connected to the fixing mechanism through the ear seat, thereby increasing the stability of the installation.

[0046] The utility model exemplarily provides an exhaust pipe, such as Figure 4 As shown, a trumpet-shaped collector is provided on the side of the exhaust pipe facing the evaporation pipe, and a defoamer covering the collector cross section is provided on the collector. Since the utility model needs to collect the gas phase components after flash evaporation as much as possible and transport them to the next mechanism, the trumpet-shaped collector can be added to increase the collection surface of the gas phase components and improve the collection efficiency.

[0047] The utility model exemplarily provides a noise reduction mechanism, such as Figure 3 As shown, it includes: the lower surfaces of the first-stage evaporator 7 and the second-stage evaporator 4 are both movably mounted with a base 16, the upper surface of the base 16 is fixedly connected with a plurality of damping rods 17, the upper surface of the damping rod 17 is fixedly connected with a support plate 18, and a damping spring 19 is fixedly connected between the lower surface of the support plate 18 and the upper surface of the base 16.

[0048] When the primary evaporator 7 and the secondary evaporator 4 are in operation, vibration force is generated, which is transmitted to the support plate 18 at the bottom through the vibration force, and then the damping spring 19 is squeezed and buffered to unload the force. The damping spring 19 is moved up and down in a stable horizontal manner in cooperation with the damping rod 17 on the base 16, thereby ensuring the stability of shock absorption, thereby reducing the vibration of the primary evaporator 7 and the secondary evaporator 4 and reducing the noise generated by the vibration force.

[0049] The working principle of the above mechanism is that when the primary evaporator 7 and the secondary evaporator 4 are in operation, vibration force will be generated, which will be transmitted to the support plate 18 at the bottom through the vibration force, and then the damping spring 19 will be squeezed and buffered to unload the force, and the damping rod 17 on the base 16 will move the damping spring 19 up and down in a stable horizontal manner, thereby ensuring the stability of shock absorption, thereby reducing the vibration of the primary evaporator 7 and the secondary evaporator 4 and reducing the noise generated by the vibration force.

[0050] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without deviating from the technical concept of the utility model through the above description. The technical scope of the utility model is not limited to the content of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A separation system for low-pressure carbonyl synthesis of acetic acid, comprising a reaction kettle (12), a lightness removal tower (1), and an evaporation system connecting the reaction kettle (12) and the lightness removal tower (1), characterized in that: The evaporation system comprises: a primary evaporator (7) and a secondary evaporator (4), wherein: The top outlet of the light-removal tower (1) is connected to an inlet of the reaction kettle (12) through a first connecting pipe (2), and the inlet is connected to the gas phase outlet of the secondary evaporator (4) through a second connecting pipe (3); The liquid phase outlet end of the secondary evaporator (4) is connected to a liquid phase material inlet end of the reaction kettle (12) through a fourth connecting pipe (6); the inlet end of the secondary evaporator (4) is connected to the liquid phase outlet end of the primary evaporator (7) through a third connecting pipe (5); The gas phase outlet end of the primary evaporator (7) is connected to the other inlet end of the reaction kettle (12) through a sixth connecting pipe (9); the inlet end of the primary evaporator (7) is connected to the reaction liquid outlet end of the reaction kettle (12) through a fifth connecting pipe (8); The fourth connecting pipe (6), the third connecting pipe (5), the fifth connecting pipe (8) and the sixth connecting pipe (9) are respectively installed with an adjustment mechanism (15).

2. The separation system suitable for low-pressure carbonyl synthesis of acetic acid according to claim 1, characterized in that: The primary evaporator (7) and the secondary evaporator (4) have the same structure, both comprising: a cylindrical chamber with a wider top and a triangular cone-shaped chamber at the bottom, which are interconnected; an evaporation tube is provided in the cylindrical chamber at the bottom near the top of the triangular cone-shaped chamber, and the inlet end of the evaporation tube extends to the outside of the cylindrical chamber to serve as the inlet end of the evaporator; an exhaust pipe is provided at the top of the cylindrical chamber, and one end of the exhaust pipe extends to the outside of the cylindrical chamber to serve as the gas phase outlet end of the evaporator; and a liquid phase outlet end controlled by a drainage mechanism is provided at the bottom of the triangular cone-shaped chamber at the top of the triangular cone.

3. The separation system suitable for low-pressure carbonyl synthesis of acetic acid according to claim 2, characterized in that: The outer wall of the cylindrical chamber is provided with an ear seat above the evaporation tube.

4. The separation system suitable for low-pressure carbonyl synthesis of acetic acid according to claim 2, characterized in that: A trumpet-shaped collector is arranged on one side of the exhaust pipe facing the evaporation pipe, and a defoamer covering the cross section of the collector is arranged on the collector.

5. The separation system suitable for low-pressure carbonyl synthesis of acetic acid according to claim 1, characterized in that: The fourth connecting pipe (6) is connected to the inlet end of the first pressurizing device (14), and the outlet end of the first pressurizing device (14) is connected to a liquid phase material inlet end of the reaction kettle (12) through the eighth connecting pipe (13). At this time, the regulating mechanism (15) originally arranged on the fourth connecting pipe (6) is changed to be arranged on the eighth connecting pipe (13).

6. The separation system suitable for low-pressure carbonyl synthesis of acetic acid according to claim 1, characterized in that: The sixth connecting pipe (9) is connected to the inlet end of the second pressurizing device (10), and the outlet end of the second pressurizing device (10) is connected to the other inlet end of the reaction kettle (12) through the seventh connecting pipe (11).

7. The separation system suitable for low-pressure carbonyl synthesis of acetic acid according to claim 1, characterized in that: The first connecting pipe (2) is connected to the inlet end of the third pressurizing device (20), and the outlet end of the third pressurizing device (20) is connected to the other inlet end of the reaction kettle (12) through a ninth connecting pipe (21).

8. The separation system suitable for low-pressure carbonyl synthesis of acetic acid according to claim 1, characterized in that: A base (16) is movably mounted on the lower surface of the primary evaporator (7) and the secondary evaporator (4); a plurality of damping rods (17) are fixedly connected to the upper surface of the base (16); a support plate (18) is fixedly connected to the upper surface of the damping rod (17); and a damping spring (19) is fixedly connected between the lower surface of the support plate (18) and the upper surface of the base (16).

9. The separation system suitable for low-pressure carbonyl synthesis of acetic acid according to claim 5, characterized in that: The secondary evaporator (4), the third connecting pipe (5), the fourth connecting pipe (6), and the eighth connecting pipe (13) are all connected to a carbon monoxide supply system; the carbon monoxide supply system supplies carbon monoxide gas to the inside of the secondary evaporator (4), the third connecting pipe (5), the fourth connecting pipe (6), and the eighth connecting pipe (13).

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