Phase change separator and phase change separation control method

Abstract

The present invention discloses a phase change separator and a phase change separation control method, wherein the phase change separator comprises a tank body, an overflow plate, a partition, a rich phase collection pipe, a lean phase collection pipe and a sewage pipe; the overflow plate is vertically fixed inside the tank body, and the overflow plate is sequentially arranged in four pieces from back to front, and the four overflow plates divide the inner cavity of the tank body from back to front into five chambers, namely, a first static chamber, a first rich phase chamber, a second static chamber, a second rich phase chamber and a lean phase chamber, and the upper and lower parts of the overflow plates corresponding to the first rich phase chamber and the second rich phase chamber are both provided with overflow holes, and the upper part of the overflow plate corresponding to the front of the first rich phase chamber is provided with overflow holes, and the aperture of the overflow hole of the overflow plate decreases sequentially from back to front; the partition plate is correspondingly arranged between two adjacent overflow plates. The present invention can achieve a higher phase change phase separation rate under the premise of achieving efficient phase separation of the phase change absorbent, and is particularly suitable for a CO2 capture and recovery system based on a chemical absorption method.

Description

Technical Field

[0001] The present invention relates to a phase change separator for liquid phase separation and a phase change separation control method, specifically a phase change separator suitable for separating a phase change absorbent absorbing CO2 in the process of capturing CO2 by chemical absorption method and a phase change separation control method, belonging to the technical field of CO2 capture. Background Art

[0002] CCUS (Carbon Capture, Utilization and Storage) technology is a new development trend of CCS (Carbon Capture and Storage) technology, which is to collect and purify CO2 emitted from the production process of large power plants, steel mills, chemical plants and other emission sources, and then put it into new production processes for recycling, rather than simply storing it. Compared with CCS, CCUS can turn CO2 into a resource to generate economic benefits and is more practical. The capture, development and utilization of CO2 as a "potential carbon resource" has attracted more and more attention from countries around the world.

[0003] About 3 / 4 of the CO2 emitted into the atmosphere is caused by the combustion of fossil fuels. Recovering CO2 from flue gas emitted by coal-fired power plants is not only the key to carbon emission reduction in my country, but also the most economical. At present, the main methods for capturing and recovering CO2 from flue gas include chemical absorption, physical absorption, adsorption separation, membrane separation and cryogenic distillation. Among them, chemical absorption is the most commonly selected and widely used flue gas CO2 capture method in CCUS projects due to its technical maturity and application prospects. The chemical absorption method separates CO2 from other gases by selectively reacting the absorbent with the CO2 in the mixed flue gas, and regenerating it with the help of the reverse reaction of the reaction to release high-purity CO2 for enrichment. The traditional organic amine chemical absorption method has problems such as high regeneration energy consumption and insufficient absorption performance. Therefore, phase change absorbent is currently a hot research topic for CO2 absorbents. After absorbing CO2, the phase change absorbent will change from a homogeneous solution to an immiscible liquid-liquid two-phase (lean liquid phase and rich liquid phase) solution and stratify. By separating and enriching the CO2-rich rich liquid phase, the amount of regenerated liquid in the desorption tower can be greatly reduced, thereby reducing the regeneration energy consumption. However, for the absorption system that currently uses phase change absorbents to absorb CO2 and then undergoes phase change stratification, there are not only problems such as low phase change separation rate and difficulty in achieving complete separation of the lean and rich liquid phases, but also problems such as the ratio of the two phases may change from the initial ratio when they are mixed again and it is difficult to control. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention provides a phase change separator and a phase change separation control method, which can achieve a higher phase change separation rate under the premise of efficient phase separation of phase change absorbent, and is particularly suitable for CO2 capture and recovery systems based on chemical absorption.

[0005] To achieve the above purpose, the phase change separator includes a tank body, an overflow plate, a partition, a rich phase collecting pipe, a lean phase collecting pipe and a sewage pipe;

[0006] The rear end of the tank body is provided with a phase change solution input port, a flow regulating valve is provided on the phase change solution input port, and a breathing valve is provided on the top of the tank body;

[0007] The overflow plate is vertically fixedly arranged inside the tank body corresponding to the phase change absorbent input port, the bottom edge and the side edge of the overflow plate are both tightly connected to the inner surface of the tank body, an overflow channel is formed between the top edge of the overflow plate and the inner surface of the tank body, the overflow plate is sequentially arranged in four pieces from back to front, the four overflow plates divide the inner cavity of the tank body from back to front into five chambers, namely, a first static chamber, a first phase-rich chamber, a second static chamber, a second phase-rich chamber and a lean phase chamber, the upper and lower parts of the overflow plates corresponding to the first phase-rich chamber and the second phase-rich chamber are both provided with overflow holes, the upper part of the overflow plate corresponding to the front of the first phase-rich chamber is provided with an overflow hole, and the aperture of the overflow hole of the overflow plate decreases sequentially from back to front;

[0008] The partition is correspondingly arranged between two adjacent overflow plates, the top edge and the side edge of the partition are both tightly connected to the inner surface of the tank body, and a flow channel is formed between the bottom edge of the partition and the inner surface of the tank body;

[0009] The rich phase collecting pipe is connected to the inner cavity of the tank body, and the rich phase collecting pipe is correspondingly arranged at the bottom end of the first rich phase chamber and the second rich phase chamber;

[0010] The lean phase collecting pipe is connected to the inner cavity of the tank body, and the lean phase collecting pipe is correspondingly arranged at the bottom position of the lean phase chamber;

[0011] The sewage discharge pipe is connected to the inner cavity of the tank body, and the sewage discharge pipe is correspondingly arranged at the bottom end positions of the first static chamber, the second static chamber and the lean phase chamber;

[0012] On-off valves are provided on the rich phase collecting pipe, the lean phase collecting pipe and the sewage pipe.

[0013] As a further improvement of the present invention, the tank body is a horizontal structure or a vertical structure. When the tank body is a horizontal structure, the ratio of the length of the tank body to the diameter is not less than 4; when the tank body is a vertical structure, the ratio of the height of the tank body to the diameter is not less than 4.

[0014] As a preferred embodiment of the present invention, when the tank body is a horizontal structure, the ratio of the length to the diameter of the tank body is 10-15, and when the tank body is a vertical structure, the ratio of the height to the diameter of the tank body is 10-15.

[0015] As a further improvement of the present invention, the surface roughness of the inner cavity of the tank body Ra>0.4 μm.

[0016] As a further improvement of the present invention, a guide inclined plate inclined forward and downward is provided at the top edge of the overflow plate, and the angle between the guide inclined plate and the overflow plate is 30 to 45 degrees.

[0017] A phase change separation control method based on a phase change separator, which adjusts the continuous input flow of a phase change solution including a phase change absorbent to 25L / h-75L / h by controlling a flow regulating valve, controls the phase change separation temperature to 30-60°C, realizes efficient phase separation of the phase change solution through two static separations in a first static chamber and a second static chamber, collects the rich phase through a rich phase collection pipe, collects the lean phase through a lean phase collection pipe, and collects impurities through a sewage pipe.

[0018] As a further improvement scheme of the present invention, the phase change absorbent in the phase change solution includes a first solvent, or the phase change absorbent in the phase change solution includes a first solvent and a second solvent. Based on the total mass of the solvent, the mass content of the first solvent is 15 to 80 wt%, preferably 15 to 30 wt%. The first solvent is at least one of ethanolamine, N-methyldiethanolamine, triethylenetetramine, hydroxyethylethylenediamine, 2,2-dimethylcyclopropanecarboxamide, N,N-diethylethanolamine and N,N-dimethylcyclohexylamine, and the second solvent is at least one of propanol, n-butanol, water, cyclopentane sulfone, polyether, 2-amino-2-methyl-1-propanol, 3-glycol and decanol.

[0019] As an embodiment of the phase-change absorbent of the present invention, the phase-change absorbent in the phase-change solution is solvent A, and solvent A is a mixture of ethanolamine and sulfolane, wherein the mass content of ethanolamine is 20%.

[0020] As another embodiment of the phase change absorber of the present invention, the phase change absorber in the phase change solution is solvent B, and solvent B is a mixture of triethylenetetramine, N,N-diethylethanolamine and propanol, wherein the mass content of triethylenetetramine is 30%, the mass content of N,N-diethylethanolamine is 50%, and the mass content of propanol is 20%.

[0021] As another embodiment of the phase change absorbent of the present invention, the phase change absorbent in the phase change solution is solvent C, and solvent C is a mixture of N-methyldiethanolamine, n-butanol and water, wherein the mass content of n-butanol is 30%, the mass content of water is 50%, and the mass content of N-methyldiethanolamine is 20%.

[0022] Compared with the prior art, the phase change separator and phase change separation control method utilize two static separations of the first static chamber and the second static chamber to achieve efficient phase separation of the phase change solution. On the other hand, the different input flow rates of the phase change solution are controlled according to the different components of the phase change absorbent, and the phase change separation temperature is controlled according to the different components of the phase change absorbent, thereby achieving a higher phase change separation rate, which is particularly suitable for CO2 capture and recovery systems based on chemical absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the phase change separator of the present invention when it adopts a horizontal structure;

[0024] Figure 2 It is a structural schematic diagram of the phase change separator of the present invention when it adopts a vertical structure.

[0025] In the figure: 1. tank body, 11. phase change solution inlet, 12. breathing valve, 13. first static chamber, 14. first rich phase chamber, 15. second static chamber, 16. second rich phase chamber, 17. lean phase chamber, 2. overflow plate, 21. overflow hole, 22. guide inclined plate, 3. partition, 4. rich phase collecting pipe, 5. lean phase collecting pipe, 6. sewage pipe. DETAILED DESCRIPTION

[0026] The phase change separator and phase change separation control method achieve efficient phase separation of the phase change absorbent by controlling the flow rate and the static state. Figure 1 , Figure 2 The left side direction is described as the rear).

[0027] The phase change separator comprises a tank body 1, an overflow plate 2, a partition plate 3, a rich phase collecting pipe 4, a lean phase collecting pipe 5 and a sewage discharge pipe 6.

[0028] like Figure 1 , Figure 2 As shown, the tank body 1 can be a horizontal structure or a vertical structure. When the horizontal structure is adopted, the ratio of the length to the diameter of the tank body 1 is not less than 4, preferably 10 to 15. When the vertical structure is adopted, the ratio of the height to the diameter of the tank body 1 is not less than 4, preferably 10 to 15. A phase change solution input port 11 is provided at the rear end of the tank body 1, and a flow regulating valve is provided on the phase change solution input port 11. A breathing valve 12 is provided at the top of the tank body 1. To facilitate the flow of the phase change solution, the surface roughness Ra of the inner cavity of the tank body 1 is greater than 0.4μm.

[0029] The overflow plate 2 is vertically fixedly arranged inside the tank body 1 corresponding to the phase change absorbent input port 11. The bottom edge and the side edge of the overflow plate 2 are both tightly connected to the inner surface of the tank body 1. An overflow channel is formed between the top edge of the overflow plate 2 and the inner surface of the tank body 1. A guide inclined plate 22 is arranged to be inclined forward and downward at the top edge of the overflow plate 2. The angle between the guide inclined plate 22 and the overflow plate 2 is 30-45°. The overflow plates 2 are arranged in four pieces from back to front. The four overflow plates are arranged to be The plate 2 divides the inner cavity of the tank body 1 from back to front into five chambers, namely a first static chamber 13, a first rich phase chamber 14, a second static chamber 15, a second rich phase chamber 16 and a lean phase chamber 17. Overflow holes 21 are provided at the upper and lower parts of the overflow plate 2 located behind the first rich phase chamber 14 and the second rich phase chamber 16, and overflow holes 21 are provided at the upper part of the overflow plate 2 located in front of the first rich phase chamber 14, and the aperture of the overflow holes 21 of the overflow plate 2 decreases successively from back to front.

[0030] The partition 3 is correspondingly arranged between two adjacent overflow plates 2 , the top edge and the side edge of the partition 3 are both tightly connected to the inner surface of the tank body 1 , and a flow channel is formed between the bottom edge of the partition 3 and the inner surface of the tank body 1 .

[0031] The rich phase collecting pipe 4 is connected to the inner cavity of the tank body 1 , and the rich phase collecting pipe 4 is correspondingly arranged at the bottom end positions of the first rich phase chamber 14 and the second rich phase chamber 16 .

[0032] The lean phase collecting pipe 5 is connected to the inner cavity of the tank body 1 , and the lean phase collecting pipe 5 is correspondingly arranged at the bottom position of the lean phase chamber 17 .

[0033] The sewage discharge pipe 6 is connected to the inner cavity of the tank body 1 , and the sewage discharge pipe 6 is correspondingly arranged at the bottom ends of the first static chamber 13 , the second static chamber 15 and the lean phase chamber 17 .

[0034] The rich phase collecting pipe 4, the lean phase collecting pipe 5 and the sewage discharge pipe 6 are all provided with on-off valves.

[0035] When the phase change separator is used for phase change separation, the continuous input flow rate of the phase change solution is adjusted by controlling the flow regulating valve (25L / h~75L / h), and the phase change separation temperature is controlled (30~60°C). The phase change solution containing the phase change absorbent absorbing CO2 enters the first static chamber 13 of the tank body 1 through the phase change solution input port 11, and a static stratification occurs. Most of the rich phase at the bottom of the liquid surface flows forward through the overflow hole 21 located at the lower part of the overflow plate 2 to enter the first rich phase chamber 14, and the phase change solution containing the lean phase and part of the rich phase at the top of the liquid surface flows forward through the overflow hole 21 located at the upper part of the overflow plate 2 and the guide inclined plate 22. It passes through the first rich phase chamber 14 in turn and enters the second static chamber 15, and Secondary static stratification occurs in the second static chamber 15, and the rich phase at the bottom of the liquid surface in the second static chamber 15 continues to flow forward through the overflow hole 21 located at the lower part of the overflow plate 2 and enters the second rich phase chamber 16, and the lean phase at the top of the liquid surface in the second static chamber 15 continues to flow forward through the overflow hole 21 located at the upper part of the overflow plate 2 and the guide inclined plate 22 and sequentially passes through the second rich phase chamber 16 into the lean phase chamber 17 for storage. The partition 3 can play a role in blocking and forcing static backflow. The two static separations of the first static chamber 13 and the second static chamber 15 can achieve efficient phase separation of the phase change solution, and the rich phase can be collected through the rich phase collection pipe 4, the lean phase can be collected through the lean phase collection pipe 5, and the impurities can be collected through the sewage pipe 6.

[0036] The phase-change absorbent in the phase-change solution includes a first solvent, or the phase-change absorbent in the phase-change solution includes a first solvent and a second solvent. Based on the total mass of the solvent, the mass content of the first solvent is 15 to 80 wt%, preferably 15 to 30 wt%. The first solvent can be at least one of ethanolamine (MEA), N-methyldiethanolamine, triethylenetetramine, hydroxyethylethylenediamine, 2,2-dimethylcyclopropanecarboxamide, N,N-diethylethanolamine and N,N-dimethylcyclohexylamine, and the second solvent can be at least one of 1-propanol, n-butanol, water, cyclopentane sulfone, polyether, 2-amino-2-methyl-1-propanol, 3-glycol and decanol.

[0037] As an implementation manner of the phase-change absorbent in the phase-change solution, the phase-change absorbent in the phase-change solution is solvent A, and solvent A is a mixture of ethanolamine (MEA) and sulfolane, wherein the mass content of ethanolamine is 20%.

[0038] Example 1: Solvent A is used as the phase change absorbent in the phase change solution, and the ratio of the length to the diameter of the tank body 1 is 5 (the tank body 1 is a horizontal structure) or the ratio of the height to the diameter of the tank body 1 is 5 (the tank body 1 is a vertical structure), the flow rate of the phase change solution is controlled to 25L / h, and the separation temperature is controlled to 40°C. Then, when using this phase change separator for phase change separation, the phase separation rate can reach 90%.

[0039] Example 2: Solvent A is used as the phase change absorbent in the phase change solution, and the ratio of the length to the diameter of the tank body 1 is 10 (the tank body 1 is a horizontal structure) or the ratio of the height to the diameter of the tank body 1 is 10 (the tank body 1 is a vertical structure), the flow rate of the phase change solution is controlled to 50L / h, and the separation temperature is controlled to 50°C. When the phase change separation is performed using this phase change separator, the phase separation rate can reach 85%.

[0040] Example 3: Solvent A is used as the phase change absorbent in the phase change solution, and the ratio of the length to the diameter of the tank body 1 is 15 (the tank body 1 is a horizontal structure) or the ratio of the height to the diameter of the tank body 1 is 15 (the tank body 1 is a vertical structure), the flow rate of the phase change solution is controlled to 75L / h, and the separation temperature is controlled to 30°C. Then, when using this phase change separator for phase change separation, the phase separation rate can reach 80%.

[0041] As another embodiment of the phase change absorber in the phase change solution, the phase change absorber in the phase change solution is solvent B, and solvent B is a mixture of triethylenetetramine, N,N-diethylethanolamine and propanol, wherein the mass content of triethylenetetramine is 30%, the mass content of N,N-diethylethanolamine is 50%, and the mass content of propanol is 20%.

[0042] Example 4: Solvent B is used as the phase change absorbent in the phase change solution, and the ratio of the length to the diameter of the tank body 1 is 10 (the tank body 1 is a horizontal structure) or the ratio of the height to the diameter of the tank body 1 is 10 (the tank body 1 is a vertical structure), the flow rate of the phase change solution is controlled to 25L / h, and the separation temperature is controlled to 60°C. Then, when using this phase change separator for phase change separation, the phase separation rate can reach 95%.

[0043] Example 5: Solvent B is used as the phase change absorbent in the phase change solution, and the ratio of the length to the diameter of the tank body 1 is 8 (the tank body 1 is a horizontal structure) or the ratio of the height to the diameter of the tank body 1 is 8 (the tank body 1 is a vertical structure), the flow rate of the phase change solution is controlled to 50L / h, and the separation temperature is controlled to 50°C. Then, when the phase change separation is performed using this phase change separator, the phase separation rate can reach 92%.

[0044] Example 6: Solvent B is used as the phase change absorbent in the phase change solution, and the ratio of the length to the diameter of the tank body 1 is 10 (the tank body 1 is a horizontal structure) or the ratio of the height to the diameter of the tank body 1 is 10 (the tank body 1 is a vertical structure), the flow rate of the phase change solution is controlled to 75L / h, and the separation temperature is controlled to 30°C. Then, when using this phase change separator for phase change separation, the phase separation rate can reach 90%.

[0045] As another embodiment of the phase change absorbent in the phase change solution, the phase change absorbent in the phase change solution is solvent C, which is a mixture of N-methyldiethanolamine, n-butanol and water, wherein the mass content of n-butanol is 30%, the mass content of water is 50%, and the mass content of N-methyldiethanolamine is 20%.

[0046] Example 7: Solvent C is used as the phase change absorbent in the phase change solution, and the ratio of the length to the diameter of the tank body 1 is 8 (the tank body 1 is a horizontal structure) or the ratio of the height to the diameter of the tank body 1 is 8 (the tank body 1 is a vertical structure), the flow rate of the phase change solution is controlled to 25L / h, and the separation temperature is controlled to 40°C. Then, when using this phase change separator for phase change separation, the phase separation rate can reach 98%.

[0047] Example 8: Solvent C is used as the phase change absorbent in the phase change solution, and the ratio of the length to the diameter of the tank body 1 is 12 (the tank body 1 is a horizontal structure) or the ratio of the height to the diameter of the tank body 1 is 12 (the tank body 1 is a vertical structure), the flow rate of the phase change solution is controlled to 50L / h, and the separation temperature is controlled to 55°C. Then, when using this phase change separator for phase change separation, the phase separation rate can reach 95%.

[0048] Example 9: Solvent C is used as the phase change absorbent in the phase change solution, and the ratio of the length to the diameter of the tank body 1 is 15 (the tank body 1 is a horizontal structure) or the ratio of the height to the diameter of the tank body 1 is 15 (the tank body 1 is a vertical structure), the flow rate of the phase change solution is controlled to 75L / h, and the separation temperature is controlled to 45°C. Then, when using this phase change separator for phase change separation, the phase separation rate can reach 90%.

[0049] The phase change separator and phase change separation control method utilize two static separations of the first static chamber and the second static chamber to realize efficient phase separation of the phase change solution. On the other hand, the different input flow rates of the phase change solution are controlled according to the different components of the phase change absorbent, and the phase change separation temperature is controlled according to the different components of the phase change absorbent, thereby achieving a higher phase change separation rate. The method is particularly suitable for a CO2 capture and recovery system based on chemical absorption.

Claims

1. A separator for separating a phase change absorbent for absorbing CO2, comprising a tank body (1), an overflow plate (2), a baffle (3), a rich phase collection pipe (4), a lean phase collection pipe (5) and a sewage discharge pipe (6); a phase change solution input port (11) is provided at the rear end of the tank body (1), a flow regulating valve is provided on the phase change solution input port (11), and a breathing valve (12) is provided at the top end of the tank body (1); the characteristics are as follows: The tank body (1) is a horizontal structure or a vertical structure. When the tank body (1) is a horizontal structure, the ratio of the length to the diameter of the tank body (1) is not less than 4. When the tank body (1) is a vertical structure, the ratio of the height to the diameter of the tank body (1) is not less than 4. The overflow plate (2) is vertically fixedly arranged inside the tank body (1) corresponding to the phase change absorbent input port (11); the bottom edge and the side edge of the overflow plate (2) are both tightly connected to the inner surface of the tank body (1); an overflow channel is formed between the top edge of the overflow plate (2) and the inner surface of the tank body (1); the overflow plates (2) are arranged in four pieces in sequence from back to front; the four overflow plates (2) divide the inner cavity of the tank body (1) from back to front into a first static chamber (13), a first phase-rich chamber (14), and a second phase-rich chamber (15). The first phase-rich chamber (14), the second static chamber (15), the second phase-rich chamber (16) and the lean phase chamber (17) are five chambers, the upper and lower parts of the overflow plate (2) located behind the first phase-rich chamber (14) and the second phase-rich chamber (16) are provided with overflow holes (21), the upper part of the overflow plate (2) located in front of the first phase-rich chamber (14) is provided with an overflow hole (21), and the aperture of the overflow hole (21) of the overflow plate (2) decreases in sequence from the back to the front; The partition plate (3) is correspondingly arranged between two adjacent overflow plates (2); the top edge and the side edge of the partition plate (3) are both tightly connected to the inner surface of the tank body (1); and a flow channel is formed between the bottom edge of the partition plate (3) and the inner surface of the tank body (1); The rich phase collecting pipe (4) is connected to the inner cavity of the tank body (1) through-through, and the rich phase collecting pipe (4) is correspondingly arranged at the bottom ends of the first rich phase chamber (14) and the second rich phase chamber (16); The lean phase collection pipe (5) is connected to the inner cavity of the tank body (1) through-through, and the lean phase collection pipe (5) is correspondingly arranged at the bottom position of the lean phase chamber (17); The sewage discharge pipe (6) is connected to the inner cavity of the tank body (1), and the sewage discharge pipe (6) is correspondingly arranged at the bottom ends of the first static chamber (13), the second static chamber (15) and the lean phase chamber (17); The rich phase collecting pipe (4), the lean phase collecting pipe (5) and the sewage discharge pipe (6) are all provided with on-off valves.

2. The separator according to claim 1, characterized in that When the tank body (1) is a horizontal structure, the ratio of the length of the tank body (1) to the diameter is 10 to 15; when the tank body (1) is a vertical structure, the ratio of the height of the tank body (1) to the diameter is 10 to 15.

3. The separator according to claim 1, characterized in that The surface roughness of the inner cavity of the tank body (1) is Ra>0.4 μm.

4. The separator according to claim 1, characterized in that A guide inclined plate (22) is provided at the top edge of the overflow plate (2) and is arranged to be inclined forward and downward, and the angle between the guide inclined plate (22) and the overflow plate (2) is 30 to 45 degrees.

5. A separation control method based on the separator according to claim 1, characterized in that: The continuous input flow rate of the phase change solution including the phase change absorbent is adjusted to 25 L / h to 75 L / h by controlling the flow regulating valve, and the separation temperature is controlled to be 30 to 60° C. The phase change solution is efficiently separated by two static separations in the first static chamber (13) and the second static chamber (15). The rich phase is collected by the rich phase collection pipe (4), the lean phase is collected by the lean phase collection pipe (5), and the impurities are collected by the sewage pipe (6).

6. The separation control method according to claim 5, characterized in that: The phase-change absorbent in the phase-change solution includes a first solvent, or the phase-change absorbent in the phase-change solution includes a first solvent and a second solvent. Based on the total mass of the solvent, the mass content of the first solvent is 15 to 80 wt %. The first solvent is at least one of ethanolamine, N-methyldiethanolamine, triethylenetetramine, hydroxyethylethylenediamine, 2,2-dimethylcyclopropanecarboxamide, N,N-diethylethanolamine and N,N-dimethylcyclohexylamine, and the second solvent is at least one of propanol, n-butanol, water, cyclopentane sulfone, polyether, 2-amino-2-methyl-1-propanol, 3-glycol and decanol.

7. The separation control method according to claim 6, characterized in that: The phase change absorbent in the phase change solution is solvent A, which is a mixture of ethanolamine and sulfolane, wherein the mass content of ethanolamine is 20%.

8. The separation control method according to claim 6, characterized in that: The phase change absorbent in the phase change solution is solvent B, which is a mixture of triethylenetetramine, N,N-diethylethanolamine and propanol, wherein the mass content of triethylenetetramine is 30%, the mass content of N,N-diethylethanolamine is 50%, and the mass content of propanol is 20%.

9. The separation control method according to claim 6, characterized in that: The phase change absorbent in the phase change solution is solvent C, which is a mixture of N-methyldiethanolamine, n-butanol and water, wherein the mass content of n-butanol is 30%, the mass content of water is 50%, and the mass content of N-methyldiethanolamine is 20%.

Images