A process for desalting and dechlorinating lean amine solution

Abstract

The invention discloses a process method for desalting and dechlorinating lean amine liquid, relates to the technical field of desalting and dechlorinating lean amine liquid, and comprises the following two treatment methods: a high-efficiency desalting method and a precise dechlorination method. The invention aims at the problems in the existing amine liquid, combines the technical demand for improving the energy efficiency of the amine liquid system, and realizes high-efficiency desalting and deep dechlorination in the amine liquid through the integration of multiple technologies. Through the process method for desalting and dechlorinating lean amine liquid of the invention, the heat-stable salt content in the amine liquid system is controlled to be below 1%, the chloride ion content is controlled to be below 50 mg / L, and the overall cleanliness of the amine liquid system is improved, thereby ensuring the operating efficiency of the amine liquid system. The method of the invention has a streamlined process, low investment cost, low operating cost, and significant treatment effect.

Description

Technical Field

[0001] The invention relates to the technical field of desalination and dechlorination of lean amine liquid, and in particular to a process for desalination and dechlorination of lean amine liquid. Background Art

[0002] Amine solution is a type of organic alkaline solution, usually referring to a weakly alkaline organic amine solvent used to absorb hydrogen sulfide or carbon dioxide in the desulfurization and decarbonization chemical process. There are many ethanolamines, and the common ones include monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), N-methyldiethanolamine (MDEA), etc., or their mixtures.

[0003] Amines are commonly used in chemical processes such as petroleum, natural gas, coal chemical industry, and ammonia synthesis to remove impurities such as hydrogen sulfide and carbon dioxide from feed gas by adsorption. After being heated and distilled with an organic solvent, the liquid is returned to the adsorption tower for recycling. The liquid after the hydrogen sulfide and carbon dioxide are completely released is called lean amine. After heat exchange, the lean amine temperature can be reduced to below 50°C.

[0004] The amine liquid system is the third largest logistics system in refining and chemical enterprises, second only to crude oil and circulating water systems. Its operating performance is directly related to product compliance and the smooth operation of the entire process.

[0005] In the amine desulfurization process, various anions accumulate within the system due to factors such as the degradation of the solvent amine itself, impurities in the feed gas, and material carryover, resulting in the formation of heat-stable salts. These salts cannot be regenerated and decomposed by heating (120°C) and remain stable in the organic solvent system, hence the collective term "heat-stable salts" (HSS). Common examples include chlorides, hydrochlorides, sulfates, formates, acetates, oxalates, thiocyanates, and thiosulfates.

[0006] Based on research and recent domestic equipment operation experience, the total level of heat-stable salts should not exceed 1%, and the chloride ion content should be controlled at 50 mg / L. The accumulation of heat-stable salts, especially chloride ions, can lead to a series of problems, such as equipment corrosion, organic solvent loss, filter plugging, and organic solvent foaming, which can affect subsequent hydrocracking processes and reduce product quality.

[0007] After summarizing the engineering projects, the following common problems exist in domestic amine liquid systems:

[0008] 1. High salt content, which continues to accumulate, including metal cations and anions (including heat-stable salts);

[0009] 2. Chloride ion content continues to accumulate and is difficult to remove, continuously corroding equipment and affecting subsequent processes;

[0010] 3. Oil is introduced into the system and accumulates continuously;

[0011] 4. The organic matter continues to accumulate, causing the amine solution to change color and foam;

[0012] 5. Suspended solids continue to accumulate, causing equipment corrosion and blockage. Summary of the Invention

[0013] The purpose of the present invention is to solve the problems existing in the prior art and to propose a process for desalting and dechlorinating lean amine solution.

[0014] In order to achieve the above object, the present invention adopts the following technical solutions:

[0015] A process for desalting and dechlorinating lean amine solution, comprising the following two treatment methods:

[0016] (1) Efficient desalination method

[0017] The high-efficiency desalination method includes at least the following equipment: precision filter, wastewater tank left wastewater pump, right wastewater pump, filter A, amine liquid tank, amine liquid pump, filter B, booster pump, polar water tank, polar water pump, filter C, electrodialysis equipment, alkali tank, acid tank, regeneration pump, desalination high-speed bed;

[0018] After the lean amine liquid is transported to the lean amine liquid inlet N3, it enters the precision filter. After being filtered, the lean amine liquid enters the amine liquid tank. After reaching the liquid level set inside the amine liquid tank, it waits for startup. After the desalted water is transported to the desalted water inlet N1, it enters the wastewater tank. After reaching the liquid level in the wastewater tank, it waits for startup. The polar water tank is equipped with a 1% concentration of salt solution.

[0019] Start the amine liquid pump, right wastewater pump, and polar water pump, and start the electrodialysis equipment. The lean amine liquid, desalted water, and polar water enter the filter A, filter B, and filter C on each channel respectively, and then enter the electrodialysis equipment for cyclic desalination. Under the action of the electric field of the electrodialysis equipment, desalination is rapid.

[0020] When the salt content of the wastewater tank is greater than 15%, the wastewater discharge process is executed through the left wastewater pump, and the wastewater is discharged through the electrodialysis wastewater outlet N2, and the desalted water inlet N1 is replenished with new desalted water.

[0021] When the salt content in the amine liquid tank is close to 1%, the lean amine liquid is pumped into the desalting high-speed bed through the booster pump, and the lean amine liquid is deeply desalted by the desalting high-speed bed;

[0022] The salt content of the amine solution after treatment by the desalting high-speed bed is less than 1%, and it is discharged back to the original amine solution system through the water outlet N7;

[0023] After a period of operation, the desalination high-speed bed needs to be regenerated and flushed. The pressurized desalination water is introduced through the desalination water port N9 to flush the desalination high-speed bed. Nitrogen is introduced through the nitrogen port N8 to discharge waste liquid and scrub the desalination high-speed bed.

[0024] The acid enters the acid tank through the acid supply port N5, and the alkali enters the alkali tank through the alkali supply port N6. The acid and alkali in the acid tank and alkali tank are respectively passed into the desalination high-speed bed through the regeneration pump, and the desalination high-speed bed is used for regeneration;

[0025] The wastewater generated by the desalination high-speed bed is discharged through the wastewater outlet N10.

[0026] Precision chlorine removal method

[0027] The precision dechlorination method includes at least the following equipment: precision filter, wastewater tank, left wastewater pump, right wastewater pump, filter A, amine liquid tank, high-pressure pump, amine liquid pump, filter B, booster pump, polar water tank, polar water pump, filter C, electrodialysis equipment, spiral ion screening membrane, alkali tank, acid tank, regeneration pump, desalination high-speed bed;

[0028] After the lean amine liquid is transported to the lean amine liquid inlet N3, it enters the precision filter. After being filtered, the lean amine liquid enters the amine liquid tank. After reaching the liquid level set inside the amine liquid tank, it waits for startup. After the desalted water is transported to the desalted water inlet N1, it enters the wastewater tank. After reaching the liquid level in the wastewater tank, it waits for startup. The polar water tank is equipped with a 1% concentration of salt solution.

[0029] Start the amine liquid pump, the right wastewater pump, the pole water pump, and the electrodialysis equipment. Start the amine liquid pump, the right wastewater pump, the pole water pump, and the electrodialysis equipment. The lean amine liquid, desalted water, and pole water enter the filter A, filter B, and filter C on each channel respectively, and then enter the electrodialysis equipment for cyclic desalination. Under the action of the electric field of the electrodialysis equipment, desalination is rapid.

[0030] When the salt content of the wastewater tank is greater than 15%, the wastewater discharge process is executed through the left wastewater pump, and the wastewater is discharged through the electrodialysis wastewater outlet N2, and the desalted water inlet N1 is replenished with new desalted water.

[0031] When the salt content in the amine liquid tank 6 is close to 1%, the lean amine liquid is pumped into the spiral ion screening membrane through a high-pressure pump, and the chloride ions are screened by the spiral ion screening membrane, thereby enriching the lean amine liquid containing a high concentration of chloride ions;

[0032] The lean amine solution rich in chloride ions produced by the spiral ion screening membrane is passed into the desalination high-speed bed. The chloride ion content of the amine solution treated by the desalination high-speed bed is less than 50 mg / L and is discharged back to the original amine solution system through the water outlet N7;

[0033] After a period of operation, the desalination high-speed bed and the spiral ion screening membrane need to be regenerated and flushed. Pressurized desalination water is introduced through the desalination water port N9 to flush the desalination high-speed bed. Nitrogen is introduced through the nitrogen port N8 to discharge waste liquid and scrub the desalination high-speed bed.

[0034] The acid enters the acid tank and the alkali tank through the acid supply port N5, and the alkali enters the alkali tank through the alkali supply port N6. The acid and alkali in the acid tank and the alkali tank are respectively passed into the desalination high-speed bed and the spiral ion screening membrane through the regeneration pump, and the desalination high-speed bed and the spiral ion screening membrane are used for regeneration;

[0035] The wastewater generated by the spiral ion screening membrane is discharged through the wastewater outlet N4, and the wastewater generated by the desalination high-speed bed is discharged through the wastewater outlet N10.

[0036] The above technical solution further includes:

[0037] The precision filter is filled with a microporous pleated filter element with a filtration accuracy of 0.1 μm.

[0038] The above technical solution further includes:

[0039] The right wastewater pump, amine liquid pump and extreme water pump are low-pressure centrifugal fluoroplastic pumps with a lift of less than 15 meters. The high-pressure pump is a variable frequency centrifugal pump with a lift of 200 meters. The booster pump is a centrifugal pump with a lift of 40 meters.

[0040] The above technical solution further includes:

[0041] The left wastewater pump and the regeneration pump are centrifugal fluoroplastic pumps.

[0042] The above technical solution further includes:

[0043] The wastewater tank, amine liquid tank, extreme water tank, alkali tank and acid tank are normal pressure storage tanks and are nitrogen-sealed.

[0044] The above technical solution further includes:

[0045] The filter A, filter B and filter C are filled with filter bags with a filtration accuracy of 1 μm.

[0046] The above technical solution further includes:

[0047] The electrodialysis equipment is a homogeneous membrane two-compartment membrane stack, the membrane stack is modular, and each group of membrane stacks consists of 50 pairs.

[0048] The above technical solution further includes:

[0049] The rolled ion screening membrane is a rolled membrane assembly, and its structure refers to the reverse osmosis membrane assembly 8040. The rolled ion screening membrane is a polyamide membrane, which has high selectivity for chloride ions. At the same time, the membrane assembly contains a strong alkaline anion resin, which can be used to first adsorb other anions in the lean amine solution enriched with chloride ions.

[0050] The above technical solution further includes:

[0051] The desalination high-speed bed is a resin bed designed using flat bed ion exchange desalination technology, with an operating flow rate of up to 80 meters per hour and a resin particle size of 0.1-0.3 mm.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The present invention addresses the problems in existing amine liquids, combines the technical requirements for improving the energy efficiency of amine liquid systems, and integrates multiple technologies to achieve efficient desalination and deep dechlorination in amine liquids. Through a process for desalting and dechlorinating lean amine liquids according to the present invention, the heat-stable salt content in the amine liquid system is controlled to be below 1%, the chloride ion content is controlled to be below 50 mg / L, and the overall cleanliness of the amine liquid system is improved, thereby ensuring the operating efficiency of the amine liquid system. The method of the invention has a streamlined process, low investment cost, low operating cost, and significant treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a schematic diagram of a process for desalting and dechlorinating lean amine solution proposed by the present invention.

[0055] In the figure: 1. Precision filter; 2. Wastewater tank; 3. Left wastewater pump; 4. Right wastewater pump; 5. Filter A; 6. Amine liquid tank; 7. High-pressure pump; 8. Amine liquid pump; 9. Filter B; 10. Booster pump; 11. Electrode water tank; 12. Electrode water pump; 13. Filter C; 14. Electrodialysis equipment; 15. Rolled ion screening membrane; 16. Alkali tank; 17. Acid tank; 18. Regeneration pump; 19. Desalination high-speed bed. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0057] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0058] like Figure 1 As shown, the present invention proposes a process for desalting and dechlorinating lean amine solution, which includes the following two treatment methods:

[0059] (1) Efficient desalination method

[0060] The high-efficiency desalination method includes at least the following equipment: precision filter 1, wastewater tank 2, left wastewater pump 3, right wastewater pump 4, filter A5, amine liquid tank 6, amine liquid pump 8, filter B9, booster pump 10, extreme water tank 11, extreme water pump 12, filter C13, electrodialysis equipment 14, alkali tank 16, acid tank 17, regeneration pump 18, desalination high-speed bed 19;

[0061] After being transported to the lean amine liquid inlet N3, the lean amine liquid enters the precision filter 1. After being filtered, the lean amine liquid enters the amine liquid tank 6. After reaching the liquid level set inside the amine liquid tank 6, it waits for startup. After being transported to the desalted water inlet N1, the desalted water enters the wastewater tank 2. After reaching the liquid level set inside the wastewater tank 2, it waits for startup. The polar water tank 11 is configured with a 1% concentration of salt solution.

[0062] Start the amine liquid pump 8, the right wastewater pump 4, the polar water pump 12, and the electrodialysis device 14. The lean amine liquid, desalted water, and polar water enter the filter A5, filter B9, and filter C13 on each channel respectively, and then enter the electrodialysis device 14 for cyclic desalination. Under the action of the electric field of the electrodialysis device 14, desalination is rapid.

[0063] When the salt content of wastewater tank 2 is greater than 15%, the wastewater discharge process is performed through the left wastewater pump 3, and the wastewater is discharged through the electrodialysis wastewater outlet N2 and replenished with new desalted water through the desalted water inlet N1;

[0064] When the salt content in the amine liquid tank 6 is close to 1%, the lean amine liquid is pumped into the desalting high-speed bed 19 through the booster pump 10, and the lean amine liquid is deeply desalted by the desalting high-speed bed 19;

[0065] The salt content of the amine solution after treatment by the desalting high-speed bed 19 is less than 1%, and it is discharged back to the original amine solution system through the water outlet N7;

[0066] After a period of operation, the desalination high-speed bed 19 needs to be regenerated and flushed. The pressurized desalted water enters through the desalted water port N9 to flush the desalination high-speed bed 19. Nitrogen enters through the nitrogen port N8 to discharge waste liquid and scrub the desalination high-speed bed 19.

[0067] The acid enters the acid tank 17 and the alkali tank 16 through the acid supply port N5, and the alkali enters the alkali supply port N6 respectively. The acid and alkali in the acid tank 17 and the alkali tank 16 are respectively passed into the desalination high-speed bed 19 through the regeneration pump 18, and the desalination high-speed bed 19 is used for regeneration;

[0068] The wastewater generated by the desalination high-speed bed 19 is discharged through the wastewater outlet N10.

[0069] After treatment with the high-efficiency desalination method, the thermally stable salt content of the amine solution system is controlled to <1%, sodium and other metal cations are <500mg / L, and suspended solids and oil substances are <100mg / L. The high-efficiency desalination method has a large salt capacity and can desalinate up to 100kg / h.

[0070] (2) Precision chlorine removal method

[0071] The precision dechlorination method includes at least the following equipment: precision filter 1, wastewater tank 2, left wastewater pump 3, right wastewater pump 4, filter A5, amine liquid tank 6, high-pressure pump 7, amine liquid pump 8, filter B9, booster pump 10, polar water tank 11, polar water pump 12, filter C13, electrodialysis equipment 14, spiral ion screening membrane 15, alkali tank 16, acid tank 17, regeneration pump 18, desalination high-speed bed 19;

[0072] After being transported to the lean amine liquid inlet N3, the lean amine liquid enters the precision filter 1. After being filtered, the lean amine liquid enters the amine liquid tank 6. After reaching the liquid level set inside the amine liquid tank 6, it waits for startup. After being transported to the desalted water inlet N1, the desalted water enters the wastewater tank 2. After reaching the liquid level set inside the wastewater tank 2, it waits for startup. The polar water tank 11 is configured with a 1% concentration of salt solution.

[0073] Start the amine pump 8, the right wastewater pump 4, the polar water pump 12, and the electrodialysis device 14. Start the amine pump 8, the right wastewater pump 4, the polar water pump 12, and the electrodialysis device 14. The lean amine solution, desalted water, and polar water enter the filter A5, filter B9, and filter C13 on each channel respectively, and then enter the electrodialysis device 14 for circulated desalination. Under the action of the electric field of the electrodialysis device 14, desalination is rapid;

[0074] When the salt content of wastewater tank 2 is greater than 15%, the wastewater discharge process is performed through the left wastewater pump 3, and the wastewater is discharged through the electrodialysis wastewater outlet N2 and replenished with new desalted water through the desalted water inlet N1;

[0075] When the salt content in the amine liquid tank 6 is close to 1%, the lean amine liquid is pumped into the spiral ion screening membrane 15 by the high-pressure pump 7, and the chloride ions are screened by the spiral ion screening membrane 15, thereby enriching the lean amine liquid containing a high concentration of chloride ions;

[0076] The lean amine solution rich in chloride ions produced by the spiral ion screening membrane 15 is passed into the desalination high-speed bed 19. The chloride ion content of the amine solution treated by the desalination high-speed bed 19 is less than 50 mg / L, and the solution is discharged back to the original amine solution system through the water outlet N7.

[0077] After a period of operation, the desalination high-speed bed 19 and the spiral ion screening membrane 15 need to be regenerated and flushed. Pressurized desalted water is introduced through the desalination inlet N9 to flush the desalination high-speed bed 19. Nitrogen is introduced through the nitrogen inlet N8 to drain the waste liquid and scrub the desalination high-speed bed 19.

[0078] The acid enters the acid tank 17 and the alkali tank 16 through the acid supply port N5, and the alkali enters the alkali tank 16 through the alkali supply port N6. The acid and alkali in the acid tank 17 and the alkali tank 16 are respectively passed into the desalination high-speed bed 19 and the spiral ion-sieving membrane 15 through the regeneration pump 18, and the desalination high-speed bed 19 and the spiral ion-sieving membrane 15 are used for regeneration;

[0079] The wastewater generated by the spiral ion screening membrane 15 is discharged through the wastewater outlet N4, and the wastewater generated by the desalination high-speed bed 19 is discharged through the wastewater outlet N10.

[0080] After precise dechlorination treatment, the heat-stable salt content of the amine solution system is controlled to be less than 1%, the chloride ion content is less than 50 mg / L, the metal cations such as sodium are less than 500 mg / L, and the suspended solids and oil substances are less than 100 mg / L.

[0081] Furthermore, the precision filter 1 is filled with a microporous pleated filter element with a filtration accuracy of 0.1 μm.

[0082] Furthermore, the right wastewater pump 4, amine liquid pump 8 and extreme water pump 12 are low-pressure centrifugal fluoroplastic pumps with a lift of less than 15 meters, the high-pressure pump 7 is a variable frequency centrifugal pump with a lift of 200 meters, and the booster pump 10 is a centrifugal pump with a lift of 40 meters.

[0083] Furthermore, the left wastewater pump 3 and the regeneration pump 18 are centrifugal fluoroplastic pumps.

[0084] Furthermore, the wastewater tank 2, the amine liquid tank 6, the polar water tank 11, the alkali tank 16 and the acid tank 17 are normal pressure storage tanks and are nitrogen-sealed.

[0085] Furthermore, filter A5, filter B9, and filter C13 are filled with filter bags, and the filtration accuracy is 1 μm.

[0086] Furthermore, the electrodialysis equipment 14 is a homogeneous membrane two-compartment membrane stack, the membrane stack is modular, and each group of membrane stacks has 50 pairs.

[0087] Furthermore, the rolled ion screening membrane 15 is a rolled membrane assembly, and its structure refers to the reverse osmosis membrane assembly 8040. The rolled ion screening membrane is a polyamide membrane, which has high selectivity for chloride ions. At the same time, the membrane assembly contains a strong alkaline anion resin, which can be used to first adsorb other anions in the lean amine solution enriched with chloride ions.

[0088] Furthermore, the desalination high-speed bed 19 is a resin bed designed using a flat bed ion exchange desalination technology, with an operating flow rate of up to 80 m / h and a resin particle size of 0.1-0.3 mm.

[0089] Example 1

[0090] The invention discloses a lean amine liquid desalination and dechlorination process method. The lean amine liquid has a storage capacity of 500 cubic meters, an initial thermally stable salt content of 3%-5%, a chloride ion content of 100-200 mg / L, and suspended solids of 500-600 mg / L. After treatment by the process of the invention, 10-15 m3 of the lean amine liquid is treated every day for 35 days. The thermally stable salt content is less than 1%, the chloride ion content is less than 30 mg / L, and the suspended solids are less than 100 mg / L. A total wastewater production of 115 tons is achieved, and the system operates stably within 35 days.

[0091] Example 2

[0092] The present invention adopts a lean amine liquid desalination and dechlorination process method. The lean amine liquid has a storage of 100 cubic meters, an initial content of thermally stable salt of 7%-9%, a chloride ion content of 80-100 mg / L, and a solid suspended matter of 200 mg / L. After being treated by the process of the present invention, the lean amine liquid is desalinated and dechlorinated at 5-10 m3 per day for 20 days. 3 The thermally stable salt content is less than 1%, the chloride ion content is less than 20 mg / L, the suspended solids are less than 100 mg / L, the total wastewater production is 60 tons, and the operation is stable within 20 days.

[0093] Example 3

[0094] The present invention adopts a lean amine liquid desalination and dechlorination process method. The lean amine liquid has a storage capacity of 500 cubic meters, an initial content of thermally stable salt of 1%-2%, a chloride ion content of 300-500 mg / L, and a solid suspended matter of 200 mg / L. After being treated by the process of the present invention, the desalination and dechlorination of the lean amine liquid is reduced by 10-15 m3 per day for 60 days. 3 The thermally stable salt content is less than 1%, the chloride ion content is less than 50 mg / L, the suspended solids are less than 100 mg / L, the total wastewater production is 50 tons, and the operation is stable within 60 days.

[0095] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A process for desalting and dechlorinating lean amine solution, characterized in that: Including precise dechlorination salt method: The precise chlorine removal method comprises at least the following equipment: a precise filter (1), a wastewater tank (2), a left wastewater pump (3), a right wastewater pump (4), a filter A (5), an amine liquid tank (6), a high-pressure pump (7), an amine liquid pump (8), a filter B (9), a booster pump (10), an extreme water tank (11), an extreme water pump (12), a filter C (13), an electrodialysis device (14), a roll-type ion screening membrane (15), an alkali tank (16), an acid tank (17), a regeneration pump (18), and a desalination high-speed bed (19); After being transported to the lean amine liquid inlet N3, the lean amine liquid enters the precision filter (1). After being filtered, the lean amine liquid enters the amine liquid tank (6). After reaching the liquid level set inside the amine liquid tank (6), it waits for startup. After being transported to the desalted water inlet N1, the desalted water enters the wastewater tank (2). After reaching the liquid level set inside the wastewater tank (2), it waits for startup. The polar water tank (11) is configured with a 1% concentration of salt solution. Start the amine liquid pump (8), the right wastewater pump (4), the polar water pump (12), and start the electrodialysis device (14). Start the amine liquid pump (8), the right wastewater pump (4), the polar water pump (12), and start the electrodialysis device (14). The lean amine liquid, the desalted water, and the polar water enter the filter A (5), the filter B (9), and the filter C (13) on each channel respectively, and then enter the electrodialysis device (14) for circulated desalination. Under the action of the electric field of the electrodialysis device (14), desalination is rapid; When the salt content in the wastewater tank (2) is greater than 15%, the wastewater discharge process is performed through the left wastewater pump (3), and the wastewater is discharged through the electrodialysis wastewater outlet N2 and replenished with new desalted water through the desalted water inlet N1; When the salt content in the amine liquid tank 6 is close to 1%, the lean amine liquid is pumped into the spiral ion screening membrane (15) through the high-pressure pump (7), and the chloride ions are screened by the spiral ion screening membrane (15), thereby enriching the lean amine liquid containing a high concentration of chloride ions; The lean amine solution rich in chloride ions produced by the spiral ion screening membrane (15) is passed into the desalination high-speed bed (19). The chloride ion content of the amine solution treated by the desalination high-speed bed (19) is less than 50 mg / L, and the solution is discharged back to the original amine solution system through the water outlet N7; After a period of operation, the desalination high-speed bed (19) and the spiral ion screening membrane (15) need to be regenerated and flushed. Pressurized desalted water is introduced through the desalination water port N9 to flush the desalination high-speed bed (19). Nitrogen is introduced through the nitrogen port N8 to discharge waste liquid and gas scrub the desalination high-speed bed (19). Acid enters the interior of the acid tank (17) and alkali tank (16) through the acid supply port N5, and alkali enters the interior of the acid tank (17) and alkali tank (16) through the alkali supply port N6. The acid solution and alkali solution in the acid tank (17) and alkali tank (16) are respectively passed into the interior of the desalination high-speed bed (19) and the spiral ion screening membrane (15) through the regeneration pump (18), and regeneration is performed using the desalination high-speed bed (19) and the spiral ion screening membrane (15); The wastewater generated by the rolled ion screening membrane (15) is discharged through the wastewater outlet N4, and the wastewater generated by the desalination high-speed bed (19) is discharged through the wastewater outlet N10; The rolled ion screening membrane (15) is a rolled membrane assembly, the structure of which is similar to that of the reverse osmosis membrane assembly 8040. The rolled ion screening membrane is a polyamide membrane, and the membrane assembly contains a strong alkaline anion resin.

2. The process for desalting and dechlorinating lean amine solution according to claim 1, characterized in that: The precision filter (1) is filled with a microporous folded filter element with a filtration accuracy of 0.1 μm.

3. The process for desalting and dechlorinating lean amine solution according to claim 1, characterized in that: The right wastewater pump (4), amine liquid pump (8) and extreme water pump (12) are low-pressure centrifugal fluoroplastic pumps with a lift of less than 15 meters. The high-pressure pump (7) is a variable frequency centrifugal pump with a lift of 200 meters. The booster pump (10) is a centrifugal pump with a lift of 40 meters.

4. The process for desalting and dechlorinating lean amine solution according to claim 1, characterized in that: The left wastewater pump (3) and the regeneration pump (18) are centrifugal fluoroplastic pumps.

5. The process for desalting and dechlorinating lean amine solution according to claim 1, characterized in that: The wastewater tank (2), amine liquid tank (6), extreme water tank (11), alkali tank (16) and acid tank (17) are normal pressure storage tanks and are nitrogen-sealed.

6. The process for desalting and dechlorinating lean amine solution according to claim 1, characterized in that: The filter A (5), filter B (9), and filter C (13) are filled with filter bags with a filtration accuracy of 1 μm.

7. The process for desalting and dechlorinating lean amine solution according to claim 1, characterized in that: The electrodialysis equipment (14) is a homogeneous membrane two-compartment membrane stack, the membrane stack is modular, and each group of membrane stacks has 50 pairs.

8. The process for desalting and dechlorinating lean amine solution according to claim 1, characterized in that: The desalination high-speed bed (19) is a resin bed designed using a flat bed ion exchange desalination technology, with an operating flow rate of up to 80 m / h and a resin particle size of 0.1-0.3 mm.

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