A method and system for desulfurization and decarbonization

Abstract

The present invention belongs to the field of environmental gas purification and energy conservation, and discloses a method and system for desulfurization and decarbonization. A desulfurization and decarbonization system includes: a flue gas absorption system, an amine liquid regeneration system; the flue gas regeneration system includes an absorption tower, a high-temperature lean-rich liquid heat exchanger, a low-temperature lean-rich liquid heat exchanger, and a heat pump system; the amine liquid regeneration system includes a regeneration tower, a thermal coupling reboiler, a high-pressure reflux tank, a reboiler, a low-pressure flash tank, a lean liquid low-temperature cooler, and a steam flash tank. A desulfurization and decarbonization method includes: in the absorption tower, the amine liquid is in countercurrent contact with the raw gas, absorbing the acidic gas in the raw gas to generate amino salt compounds, and obtaining rich amine liquid; the rich amine liquid enters the regeneration low-pressure tower and the regeneration high-pressure tower, the amino salt compounds are regenerated to release acidic gas to generate amine liquid, and then returned to the absorption tower. The present invention utilizes high-low pressure regeneration thermal coupling technology and heat pump technology to effectively reduce system energy consumption, improve overall absorption efficiency, and save equipment investment and site layout.

Description

Technical Field

[0001] The present invention belongs to the field of environmental protection gas purification and energy conservation, and relates to a method and system for desulfurization and decarbonization, specifically to a method and system for desulfurization and decarbonization from tail gas containing carbon dioxide and sulfur, and especially to a method and system for low energy consumption and high efficiency desulfurization and decarbonization for power plants, steel mills, sulfuric acid plants, etc. Background Art

[0002] As human activities expand, especially since the Industrial Revolution, industrial exhaust emissions have increased year by year. Industrial exhaust generally contains harmful substances such as carbon dioxide (CO2), sulfur dioxide (SO2), and organic sulfur, which need to be removed before they can be discharged.

[0003] Carbon dioxide is a greenhouse gas. Increased atmospheric carbon dioxide levels lead to increased absorption of longwave solar radiation, causing global temperatures to rise. This ultimately leads to melting of Arctic and Antarctic glaciers, rising sea levels, and more frequent extreme weather events such as floods, droughts, extreme cold and heat waves. Sulfur dioxide released into the atmosphere oxidizes into sulfuric acid mist or sulfate aerosols, forming acid rain and causing environmental acidification.

[0004] Currently, the most commonly used decarbonization and desulfurization method is the amine process, which uses various types of alkylolamine compounds to selectively remove acidic substances such as carbon dioxide, sulfur dioxide, and organic sulfur. Alkylolamine compounds react with acidic gases to form amino salt compounds, which decompose at high temperatures to release acidic gases. The regenerated alkylolamine compounds are then used to further absorb the acidic gases. However, the amino salt compounds require a large amount of heat to decompose during the regeneration process, resulting in high system energy consumption. Furthermore, amino salt compounds are generally highly corrosive to equipment, causing scaling. Therefore, the development of low-corrosion, low-scaling, and environmentally friendly absorption fluids and low-energy desulfurization and decarbonization processes is urgent.

[0005] Patent application CN117070256A utilizes a two-tower absorption regeneration process, resulting in high steam and circulating water consumption and high system energy consumption. The regeneration tower has only a stripping section, not a rectifying section, which easily causes amine liquid to be carried out of the tower top, resulting in significant losses. Fresh amino salt compounds on the packing in the regeneration tower fall directly into the tower bottom without being separated from the regenerated amine liquid. This prevents the amino salt compounds from being retained for regeneration, resulting in the amino salt compounds being directly discharged into the tower bottom discharge and incomplete regeneration. Summary of the Invention

[0006] The purpose of the present invention is to provide a low-energy-consumption, high-efficiency desulfurization and decarbonization equipment and process in combination with the characteristics of the desulfurization and decarbonization process, and adopt a heat comprehensive coupling utilization design to minimize energy consumption.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A desulfurization and decarbonization system, comprising: a flue gas absorption system, an amine liquid regeneration system;

[0009] The flue gas regeneration system includes an absorption tower 1, a high-temperature lean-rich liquid heat exchanger 4, a low-temperature lean-rich liquid heat exchanger 5, and a heat pump system 18; an air inlet is provided at the lower portion of the absorption tower 1, the air inlet is connected to the raw gas pipeline to allow the raw gas to enter the absorption tower from the lower portion, and an air outlet is provided at the top of the absorption tower 1, the air outlet is connected to the purified gas pipeline, and the purified gas is discharged from the air outlet; a lean liquid inlet is provided at the upper portion of the absorption tower 1, a rich liquid outlet is provided at the bottom, and a liquid collector is provided in the middle of the absorption tower 1, the liquid at the upper portion of the absorption tower 1 overflows from the liquid collector into the lower portion, and the gas at the lower portion is discharged through the liquid collector. The collector enters the upper part, and a rich liquid circulation inlet is provided in the middle below the liquid collector; a lean liquid outlet is provided in the middle of the absorption tower 1, and the lean liquid outlet is connected to the lean liquid inlet through a lean liquid circulation pipeline. The liquid collected by the liquid collector (i.e., lean amine liquid) is circulated to the absorption tower 1 through the lean liquid circulation pipeline outside the tower; the rich liquid outlet at the bottom of the absorption tower 1 is provided with a discharge pipeline and a rich liquid circulation pipeline in parallel, and the discharge pipeline is connected to the rich liquid inlet of the amine liquid regeneration system in sequence through the low-temperature lean-rich liquid heat exchanger 5 and the high-temperature lean-rich liquid heat exchanger 4, and the rich liquid circulation pipeline is connected to the rich liquid circulation inlet through the heat pump system 18;

[0010] The amine liquid regeneration system includes a regeneration tower 6, a low-pressure condenser 7, a low-pressure reflux tank 8, a thermally coupled reboiler 10, a high-pressure reflux tank 12, a reboiler 14, a low-pressure flash tank 16, a lean liquid low-temperature cooler 3, and a steam flash tank 20; the regeneration tower 6 includes an upper regeneration low-pressure tower and a lower regeneration high-pressure tower; the upper part of the regeneration low-pressure tower is a tray layer, the lower part is a packing layer, and a liquid collector is provided below the packing layer; the rich liquid inlet on the tower side of the regeneration low-pressure tower is connected to the rich liquid outlet of the high-temperature lean and rich liquid heat exchanger 4, the lower part of the regeneration low-pressure tower is equipped with a thermally coupled reboiler 10, the top gas outlet of the regeneration low-pressure tower is connected to the low-pressure condenser 7 and the low-pressure reflux tank 8 in sequence, and the liquid outlet of the low-pressure reflux tank 8 is connected to the reflux port on the upper part of the regeneration low-pressure tower; the bottom liquid outlet of the regeneration low-pressure tower is connected to the low-temperature lean and rich liquid heat exchanger 5 is connected to the rich liquid circulation pipeline; the upper part of the regeneration high-pressure tower is a tower plate layer, the lower part is a packing layer, and a liquid collector is provided below the packing layer; the rich liquid inlet of the regeneration high-pressure tower side is connected to the rich liquid outlet of the high-temperature lean-rich liquid heat exchanger 4, the lower part of the regeneration high-pressure tower is equipped with a reboiler 14, the top gas outlet of the regeneration high-pressure tower is connected to the heating medium inlet of the thermal coupling reboiler 10, and the gas phase at the top of the regeneration high-pressure tower is used as the heating heat source of the thermal coupling reboiler 10; the heating medium outlet of the thermal coupling reboiler 10 is connected to the inlet of the high-pressure reflux tank 12, the liquid outlet of the high-pressure reflux tank 12 is connected to the reflux port on the upper part of the regeneration high-pressure tower, and the gas outlet of the high-pressure reflux tank 12 is connected to the gas inlet on the upper part of the regeneration low-pressure tower, and the sulfur-containing and carbon-containing gases in the rich amine liquid are stripped by directly passing the regenerated high-temperature gas of the regeneration high-pressure tower into the regeneration low-pressure tower;

[0011] The bottom liquid outlet of the regeneration high-pressure tower is connected to the inlet of the low-pressure flash tank 16, and the liquid outlet of the low-pressure flash tank 16 is connected to the lean liquid circulation pipeline of the absorption tower 1 through the high-temperature lean-rich liquid heat exchanger 4 and the lean liquid low-temperature cooler 3 in sequence, so that the regenerated lean amine liquid is re-introduced into the absorption tower 1;

[0012] The heating medium outlet of the reboiler 14 is connected to the inlet of the steam flash tank 20, so that the reboiler steam condensate enters the steam flash tank 20. The liquid outlet of the steam flash tank 20 is respectively connected to the discharge pipeline and the steam condensate inlet of the heat pump system 18, so that part of the steam condensate is discharged out of the boundary, and the remaining steam condensate enters the heat pump system 18. The steam outlet of the heat pump system 18 is connected to the heating medium inlet of the reboiler 14, and the by-product steam obtained in the heat pump system 18 is circulated to the reboiler 14.

[0013] Preferably, the absorption tower 1 is a stand-alone tower. A liquid collector in the middle of the absorption tower 1 divides the liquid in the absorption tower into two upper and lower circulation stages: amine liquid enters the upper lean liquid inlet of the absorption tower 1, countercurrently contacts the feed gas, absorbs the acidic gas in the feed gas, and generates amino salt compounds. The liquid collected by the liquid collector (i.e., lean amine liquid) is circulated outside the tower to the absorption tower 1. The liquid collected by the liquid collector overflows to the lower part of the lower absorption tower, further countercurrently contacts the feed gas, and obtains rich amine liquid in the bottom of the absorption tower 1. Part of the rich amine liquid enters the heat pump system 18.

[0014] Preferably, a lean liquid circulation pump 19 is provided on the lean liquid circulation pipeline.

[0015] Preferably, a rich liquid pump 2 is provided at the rich liquid outlet of the absorption tower 1; the outlet of the rich liquid pump 2 is provided with a discharge pipe and a rich liquid circulation pipe in parallel, the discharge pipe is connected to the rich liquid inlet of the low-temperature lean and rich liquid heat exchanger 5, the rich liquid outlet of the low-temperature lean and rich liquid heat exchanger 5 is connected to the rich liquid inlet of the high-temperature lean and rich liquid heat exchanger 4, the rich liquid outlet of the high-temperature lean and rich liquid heat exchanger 4 is connected to the rich liquid inlet of the amine liquid regeneration system; the rich liquid circulation pipe is connected to the rich liquid inlet of the heat pump system 18, and the rich liquid outlet of the heat pump system 18 is connected to the rich liquid circulation inlet of the absorption tower 1.

[0016] The heat pump system 18 is a conventional device in the art. The rich amine liquid in the bottom of the absorption tower 1 and the lean amine liquid in the bottom of the regenerated low-pressure tower after heat exchange with the high-temperature rich-lean liquid heat exchanger 4 enter the heat pump system 18. After heat exchange with the intermediate medium, the heat is transferred to the steam condensate from the steam flash tank 20, and steam is produced as a by-product.

[0017] As a specific embodiment of the desulfurization and decarbonization system of the present invention, the heat pump system 18 includes an evaporator, a condenser, and a compressor. The rich liquid inlet of the evaporator (i.e., the heating medium inlet) is connected to the outlet of the rich liquid pump 2, and the rich liquid outlet of the evaporator (i.e., the heating medium outlet) is connected to the rich liquid circulation inlet of the absorption tower 1. The rich amine liquid exchanges heat with the intermediate medium in the evaporator. By evaporating the intermediate medium, the heat in the rich amine liquid is transferred to the intermediate medium. After the rich amine liquid cools down, it is circulated to the absorption tower 1; the intermediate medium outlet of the evaporator is connected to the inlet of the compressor. The outlet of the compressor is connected to the heating medium inlet of the condenser, the heating medium outlet of the condenser is connected to the intermediate medium inlet of the evaporator, the steam condensate inlet of the condenser is connected to the liquid outlet of the steam flash tank 20, and the steam outlet of the condenser is connected to the heating medium inlet of the reboiler 14. The heated intermediate medium is compressed by the compressor to form a high-temperature, high-pressure gas. The high-temperature, high-pressure gas enters the condenser and exchanges heat with the steam condensate from the steam flash tank 20. Through heat exchange with the steam condensate, the heat of the intermediate medium is transferred to the steam condensate in the steam flash tank 20 to produce steam as a by-product.

[0018] Specifically, an intermediate medium storage tank may be provided on the pipeline between the heating medium outlet of the condenser and the intermediate medium inlet of the evaporator.

[0019] The intermediate medium is a refrigerant, and specifically, refrigerant R-454B can be used.

[0020] A packing layer is provided at the upper and lower parts of the absorption tower 1 respectively; the packing used in the absorption tower 1 is a structured packing, which is selected from wire mesh packing such as BX, CY, or plate corrugated packing such as 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y or a structured packing with a large mass transfer area (CN207981192U), preferably 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y or a structured packing with a large mass transfer area (CN207981192U).

[0021] Specifically, the structured packing with a large mass transfer area is the structured packing with a large mass transfer area disclosed in Example 1 of CN207981192U.

[0022] The regeneration tower 6 is a tower body divided into two independent tower bodies.

[0023] Preferably, a head is provided in the middle of the regeneration tower 6 to separate the regeneration tower 6 into an upper regeneration low-pressure tower and a lower regeneration high-pressure tower.

[0024] Preferably, the rich liquid inlet of the regeneration low-pressure tower is on the tower plate layer; the air inlet of the regeneration low-pressure tower is on the tower plate layer; in the regeneration low-pressure tower, the rich liquid inlet is connected higher than the air inlet.

[0025] Preferably, the rich liquid inlet of the regeneration high-pressure tower is at the tower plate layer.

[0026] Preferably, the trays of the regeneration low-pressure tower are sieve plates, float valves, or bubble caps. The packing of the regeneration low-pressure tower is a wire mesh packing such as BX or CY, or a plate corrugated packing such as 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y, or a structured packing with a large mass transfer area (CN207981192U), preferably 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, or a structured packing with a large mass transfer area (CN207981192U).

[0027] Preferably, the tray in the regeneration high-pressure tower is a sieve plate, a float valve or a bubble cap. The packing in the regeneration high-pressure tower is a wire mesh packing such as BX or CY, or a plate corrugated packing such as 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y or a structured packing with a large mass transfer area (CN207981192U), preferably 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y or a structured packing with a large mass transfer area (CN207981192U).

[0028] Preferably, all the liquid collected by the liquid collector in the regeneration low-pressure tower enters the thermally coupled reboiler 10 ; and all the liquid collected by the liquid collector in the regeneration high-pressure tower enters the reboiler 14 .

[0029] Preferably, the thermally coupled reboiler 10 is a built-in reboiler or a K-type kettle reboiler. The reboiler 14 is a built-in reboiler or a K-type kettle reboiler.

[0030] Preferably, the gas outlet of the low-pressure reflux tank 8 is connected to an off-site acid gas treatment system, and the non-condensable acid gas is discharged from the gas outlet of the low-pressure reflux tank 8 and enters the acid gas treatment system for treatment.

[0031] Preferably, the liquid outlet of the low-pressure reflux tank 8 is provided with a low-pressure reflux pump 9, and the outlet of the low-pressure reflux pump 9 is connected to the reflux port at the upper part of the regeneration low-pressure tower.

[0032] Preferably, the liquid outlet of the regenerated low-pressure tower is provided with a low-pressure tower kettle pump 11, the outlet of the low-pressure tower kettle pump 11 is connected to the lean liquid inlet of the low-temperature lean-rich liquid heat exchanger 5, and the lean liquid outlet of the low-temperature lean-rich liquid heat exchanger 5 is connected to the rich liquid circulation pipeline.

[0033] Preferably, the liquid outlet of the high-pressure reflux tank 12 is provided with a high-pressure reflux pump 13, and the outlet of the high-pressure reflux pump 13 is connected to the reflux port at the top of the regeneration high-pressure tower.

[0034] Preferably, the liquid outlet of the low-pressure flash tank 16 is provided with a high-pressure tower bottom pump 17, the outlet of the high-pressure tower bottom pump 17 is connected to the lean liquid inlet of the high-temperature lean-rich liquid heat exchanger 4, the lean liquid outlet of the high-temperature lean-rich liquid heat exchanger 4 is connected to the lean liquid inlet of the lean liquid low-temperature cooler 3, and the lean liquid outlet of the lean liquid low-temperature cooler 3 is connected to the lean liquid circulation pipeline at the top of the absorption tower 1.

[0035] Preferably, the amine liquid regeneration system further comprises a regeneration compressor 15; the gas outlet of the low-pressure flash tank 16 and the gas outlet of the steam flash tank 20 are respectively connected to the inlet of the regeneration compressor 15, and the outlet of the regeneration compressor 15 is connected to the steam inlet of the regeneration high-pressure tower. The flash gas in the low-pressure flash tank 16 and the steam flash tank 20 is compressed by the regeneration compressor 15 and directly enters the regeneration high-pressure tower to heat the amine liquid in the tower kettle.

[0036] Another object of the present invention is to provide a method for desulfurization and decarbonization, comprising: raw gas enters an absorption tower 1 from the bottom, and amine liquid enters the absorption tower 1 from the top; in the absorption tower 1, the amine liquid and the raw gas are in countercurrent contact, absorbing acidic gases in the raw gas to generate amino salt compounds, thereby obtaining rich amine liquid; after the rich amine liquid is heated, it enters a regeneration low-pressure tower and a regeneration high-pressure tower at the same time; the amino salt compounds release acidic gases through regeneration to generate amine liquid, which returns to the absorption tower to circulate and absorb the acidic gases in the raw gas.

[0037] Specifically, the following steps are included:

[0038] Step (1): the raw gas enters the absorption tower 1 from the bottom, and the amine liquid enters the absorption tower 1 from the top. In the absorption tower, the amine liquid contacts the raw gas in countercurrent, absorbs the acidic gas in the raw gas to generate amino salt compounds, and the purified gas is discharged from the absorption tower from the top of the tower. The lean amine liquid collected by the liquid collector is returned to the absorption tower 1 through the lean liquid circulation pipeline outside the tower. Rich amine liquid is obtained in the bottom of the absorption tower 1. A part of the rich amine liquid is sent to the heat pump system 18 through the rich liquid circulation pipeline, cooled by the heat pump system, and heat is transferred to the steam condensate from the steam flash tank 20 through the intermediate medium. The cooled rich amine liquid enters the absorption tower 1 again, and the remaining rich amine liquid enters the low-temperature lean-rich liquid heat exchanger 5 and the high-temperature lean-rich liquid heat exchanger 4 in turn. In the low-temperature lean-rich liquid heat exchanger 5, the rich amine liquid exchanges heat with the lean amine liquid regenerated from the regeneration low-pressure tower. In the high-temperature lean-rich liquid heat exchanger 4, the rich amine liquid exchanges heat with the lean amine liquid discharged from the low-pressure flash tank 16. The heated rich amine liquid enters the regeneration low-pressure tower and the regeneration high-pressure tower at the same time.

[0039] Step (2): the rich amine liquid enters the regeneration low-pressure tower, is heated by the thermally coupled reboiler 10, and the amino salt compound is decomposed to obtain amine liquid and acid gas. The regeneration gas containing acid gas is discharged from the top of the regeneration low-pressure tower, condensed by the low-pressure condenser 7, and enters the low-pressure reflux tank 8. The condensate is refluxed into the regeneration low-pressure tower; the lean amine liquid in the kettle of the regeneration low-pressure tower enters the low-temperature lean-rich liquid heat exchanger 5, exchanges heat with the rich amine liquid discharged from the absorption tower 1, and is sent to the heat pump system 18 after cooling. The cooled rich amine liquid is returned to the absorption tower 1;

[0040] The rich amine liquid enters the regeneration high-pressure tower and is heated by steam in the reboiler 14. The amino salt compound decomposes to produce amine liquid and acid gas. The regeneration gas containing acid gas is discharged from the top of the regeneration high-pressure tower and enters the thermally coupled reboiler 10 as a heat source for the regeneration low-pressure tower. The regeneration gas condenses, and the condensate and acid gas enter the high-pressure reflux tank 12. The liquid is refluxed to the regeneration high-pressure tower. The non-condensable acid gas is discharged from the high-pressure reflux tank to the low-pressure tower of the regeneration tower to strip out the sulfur-containing and carbon-containing gases in the rich amine liquid. The lean amine liquid in the bottom of the regeneration high-pressure tower enters the low-pressure flash tank 16 through the pressure difference. The lean amine liquid in the low-pressure flash tank is cooled in sequence through the high-temperature rich-lean liquid heat exchanger 4 and the lean liquid low-temperature cooler 3, and then enters the absorption tower 1. The steam condensate discharged from the reboiler 14 enters the steam flash tank 20. Part of the condensate in the steam flash tank 20 is discharged to the outside, and part enters the heat pump system 18 to produce steam, which is then recirculated to the reboiler 14.

[0041] In step (1), the temperature of the raw gas is 30-90°C, and the pressure is 0-300 kPa. Usually, the flue gas is discharged at normal pressure or slightly positive pressure. The higher the pressure, the better the absorption. The content of CO2 in the raw gas is 5-30% mol, and the content of COS (carbonyl sulfide) is 10-300 mg / Nm 3 , the content of H2S is 10~150mg / Nm 3 .

[0042] The amine solution is a mixed aqueous solution of an absorbent, an activator, an antioxidant, and an enhancer. The absorbent is N-methyldiethanolamine (MDEA); the activator is one or more of methylethanolamine (MMEA), diethanolamine (DEA), piperazine (PZ), methylpiperazine (N-MPZ), ethylpiperazine (N-EPZ), and dimethylaminoethoxyethanol (DMAEE); the enhancer is one of hexahydropyrimidine, 2,5-hydroxypiperazine, and 1,3,5-triazinane; and the antioxidant is one of vanadium pentoxide, potassium chromate, and potassium metavanadate. The amine solution is environmentally friendly, has low corrosiveness, and is not prone to scaling.

[0043] In the amine solution, the concentration of the absorbent is 15-60 wt%, the concentration of the activator is 1-12 wt%, the concentration of the enhancer is 0.2-1 wt%, and the concentration of the antioxidant is 0.1-1 wt%.

[0044] The operating pressure of the absorption tower 1 is consistent with the feed gas inlet pressure; the top operating temperature of the absorption tower 1 (i.e., the temperature of the purified gas) is 40-70°C, preferably 40-60°C; the bottom operating temperature (i.e., the temperature of the rich amine liquid in the bottom) is 45-80°C, preferably 48-70°C.

[0045] The gas-liquid ratio of the bottom circulation volume of the absorption tower is 100-800, preferably 110-400, and the gas-liquid ratio of the top circulation volume is 500-1500, preferably 800-1100.

[0046] The CO2 content in the purified gas is ≤0.5% mol, and the total sulfur content is ≤20 mg / Nm 3 .

[0047] The temperature of the rich liquid inlet of the heat pump system 18 is 45-80° C., preferably 48-70° C.; the temperature of the rich liquid outlet of the heat pump system 18 is 35-55° C., preferably 35-45° C. The temperatures of the rich liquid inlet and rich liquid outlet of the heat pump system 18 correspond to the temperatures of the rich amine liquid before and after heat exchange, respectively.

[0048] In step (2), the operating pressure of the regeneration low-pressure tower is 20 to 80 kPa, preferably 20 to 50 kPa; the operating temperature of the regeneration low-pressure tower is 104 to 120° C., preferably 104 to 115° C.

[0049] The operating temperature of the low-pressure condenser 7 is 30-50°C, preferably 32-42°C.

[0050] The non-condensable acidic gas in the low-pressure reflux tank is discharged outside the boundary for acid gas treatment.

[0051] The operating pressure of the regeneration high-pressure tower is 100-200 kPa, preferably 120-150 kPa; the operating temperature of the regeneration high-pressure tower is 124-140°C, preferably 124-135°C.

[0052] The operating temperature of the lean liquid low temperature cooler 3 is 20-50°C, preferably 25-43°C.

[0053] The operating pressure of the low-pressure flash tank 16 is -20 to 50 kPa, preferably 0 to 20 kPa.

[0054] The operating pressure of the steam flash tank 20 is -10 to 60 kPa, preferably 0 to 20 kPa.

[0055] The temperature of the steam condensate inlet of the heat pump system 18 (i.e., the temperature of the steam condensate) is 96-113° C., preferably 100-105° C. The temperature of the steam outlet of the heat pump system 18 (i.e., the temperature of the steam) is 125-150° C., preferably 130-145° C.

[0056] Preferably, the acid gas obtained after flash evaporation in the low-pressure flash tank 16 is compressed by the regeneration compressor 15 and then enters the regeneration high-pressure tower; the flash gas obtained after flash evaporation in the steam flash tank 20 is compressed by the regeneration compressor 15 and then enters the regeneration high-pressure tower.

[0057] The present invention has the following beneficial effects:

[0058] The present invention combines the characteristics of desulfurization and decarbonization processes, adopts high-efficiency absorption amine liquid, and utilizes high-low pressure regenerative heat coupling technology and heat pump technology to effectively reduce system energy consumption, improve overall absorption efficiency, and save equipment investment and site layout. Specifically, it is manifested as follows:

[0059] 1. Conventional decarbonization and desulfurization systems mostly adopt a one-stage absorption and one-stage regeneration mode, which consumes a lot of system regeneration energy. The amine liquid regeneration system of the present invention adopts high-low pressure thermal coupling technology, which divides the regeneration system into low-pressure regeneration and high-pressure regeneration, saving energy.

[0060] 2. In conventional decarbonization and desulfurization regeneration systems, the regenerated rich and lean amine liquids at the bottom are not isolated, resulting in a short amine liquid residence time and poor regeneration effect when the liquid level is too low. The present invention collects the rich amine liquid from the last-stage filler in the regeneration high-pressure tower and sends it to the reboiler, which then returns it to the regeneration tower kettle, effectively separating the rich amine liquid from the lean amine liquid, thereby ensuring the regeneration time and regeneration effect of the amine liquid.

[0061] 3. Conventional decarbonization and desulfurization regeneration systems release heat during the decarbonization and desulfurization reaction, causing the outlet gas temperature to be higher than the inlet temperature. This causes water in the amine liquid to be lost into the outlet gas phase, and the amine liquid concentration to continue to increase. The present invention directly heats the amine liquid by compressing the flash steam from the condensate and then passing it directly into the regeneration high-pressure tower kettle, replenishing the lost water in the system and reducing the acid gas partial pressure. This facilitates regeneration, increases the water content of the compressed gas, increases the enthalpy value, and improves the compressor COP (cooling efficiency), thus saving more electricity. Recycling the flash steam and reducing the addition of high-quality steam can save energy by over 10%. The water content in the regeneration high-pressure tower kettle increases, and the amine liquid concentration decreases, which is more conducive to amine liquid regeneration and prevents amine liquid from deteriorating.

[0062] 4. The present invention performs low-speed flash evaporation on the high-pressure lean amine liquid. The acid gas after flash evaporation is compressed and returned to the regeneration high-pressure tower. This not only further removes the acid gas dissolved in the amine liquid, but also the compressed acid gas has a high temperature and enters the regeneration high-pressure tower to heat the amine liquid, saving steam energy by more than 11%.

[0063] 5. The present invention utilizes heat pump technology to convert the by-product steam generated by the reaction heat in the absorption tower into a regeneration unit for amine liquid, thereby reducing steam and circulating water consumption, and saving more than 50% of steam consumption.

[0064] 6. The present invention utilizes heat pump technology to remove the reaction heat in the rich amine liquid, thereby reducing the temperature of the circulating amine liquid, achieving better absorption effect, and increasing the carbon content in the rich amine liquid. This can reduce the flow rate of the circulating amine liquid in the absorption tower, reduce the equipment size, and lower the investment cost.

[0065] Table 1. Effect of amine liquid temperature on acid gas load and circulation rate

[0066]

[0067] 7. The present invention introduces the high-temperature regeneration gas from the regeneration high-pressure tower into the regeneration low-pressure tower, breaking through the thermal pinch point temperature, making heat utilization more reasonable, stripping out the sulfur-containing and carbon-containing gases in the amine liquid, and preventing the problem of repeated acid gas pollution. It also recovers heat in the exhaust gas and reduces steam consumption.

[0068] 8. The absorption tower adopts two-stage amine liquid circulation. The bottom temperature is high, the reaction is intense and the circulation volume is large, which is conducive to the hydrolysis of carbonyl sulfide. The top circulation temperature is low, which is conducive to further absorption of unremoved acidic gases and ensures the stability of the system removal effect.

[0069] 9. The present invention integrates high-pressure and low-pressure regeneration towers into one tower, effectively saving equipment floor space. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a schematic diagram of the process of the present invention for desulfurization and decarbonization process.

[0071] Figure 1 In the figure, 1-absorption tower, 2-rich liquid pump, 3-lean liquid low-temperature cooler, 4-high-temperature lean and rich liquid heat exchanger, 5-low-temperature lean and rich liquid heat exchanger, 6-regeneration tower, 7-low-pressure condenser, 8-low-pressure reflux tank, 9-low-pressure reflux pump, 10-thermal coupling reboiler, 11-low-pressure tower bottom pump, 12-high-pressure reflux tank, 13-high-pressure reflux pump, 14-reboiler, 15-regeneration compressor, 16-low-pressure flash tank, 17-high-pressure tower bottom pump, 18-heat pump system, 19-lean liquid circulation pump, 20-steam flash tank. DETAILED DESCRIPTION

[0072] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Example 1

[0073] like Figure 1 As shown, a desulfurization and decarbonization system includes: a flue gas absorption system and an amine liquid regeneration system.

[0074] The flue gas regeneration system includes an absorption tower 1, a rich liquid pump 2, a lean liquid circulation pump 19, a high-temperature lean and rich liquid heat exchanger 4, a low-temperature lean and rich liquid heat exchanger 5, and a heat pump system 18; the absorption tower 1 is an independent tower body, a liquid collector is provided in the middle of the absorption tower 1, and an upper packing layer and a lower packing layer are provided inside the absorption tower 1; an air inlet is provided at the lower part of the absorption tower 1, the air inlet is located below the lower packing layer, the air inlet is connected to the raw gas pipeline to pass the raw gas into the absorption tower from the bottom, and an air outlet is provided at the top of the absorption tower 1, the air outlet is connected to the purified gas pipeline, and the purified gas is discharged from the air outlet; a lean liquid inlet is provided at the top of the absorption tower 1, the lean liquid inlet is located above the upper packing layer, a rich liquid outlet is provided at the bottom of the absorption tower 1, and a liquid outlet is provided at the middle of the absorption tower 1 A rich liquid circulation inlet is provided between the liquid collector and the lower packing layer; a lean liquid outlet is provided in the middle of the absorption tower 1, which is connected to the lean liquid inlet via a lean liquid circulation pipeline, and a lean liquid circulation pump 19 is provided on the lean liquid circulation pipeline; the rich liquid outlet at the bottom of the absorption tower 1 is connected to the inlet of the rich liquid pump 2, and the outlet of the rich liquid pump 2 is provided with a discharge pipeline and a rich liquid circulation pipeline in parallel, the discharge pipeline is connected to the rich liquid inlet of the low-temperature lean and rich liquid heat exchanger 5, the rich liquid outlet of the low-temperature lean and rich liquid heat exchanger 5 is connected to the rich liquid inlet of the high-temperature lean and rich liquid heat exchanger 4, the rich liquid outlet of the high-temperature lean and rich liquid heat exchanger 4 is connected to the rich liquid inlet of the amine liquid regeneration system, and the rich liquid circulation pipeline is connected to the rich liquid circulation inlet of the absorption tower 1 via the heat pump system 18;The liquid collector in the middle of the absorption tower 1 divides the liquid in the absorption tower into two upper and lower circulations: the amine liquid enters from the upper part of the absorption tower 1, contacts with the feed gas in countercurrent to absorb the acidic gas in the feed gas, and generates amino salt compounds after being absorbed. The liquid collected by the liquid collector (i.e., lean amine liquid) is circulated to the absorption tower 1 through the lean liquid circulation pipeline outside the tower. The liquid collected by the liquid collector overflows to the lower part of the lower absorption tower, and further contacts with the feed gas in countercurrent to obtain rich amine liquid in the kettle of the absorption tower 1. Part of the rich amine liquid enters the heat pump system 18, which includes an evaporator, a condenser, and a compressor. The rich liquid inlet of the evaporator is connected to the outlet of the rich liquid pump 2, the rich liquid outlet of the evaporator is connected to the rich liquid circulation inlet of the absorption tower 1, and the intermediate medium outlet of the evaporator is connected to the inlet of the compressor. The compressor outlet is connected to the heating medium inlet of the condenser, the heating medium outlet of the condenser is connected to the intermediate medium inlet of the evaporator, the steam condensate inlet of the condenser is connected to the liquid outlet of the steam flash tank 20, and the steam outlet of the condenser is connected to the heating medium inlet of the reboiler 14. The rich amine liquid exchanges heat with the refrigerant R-454B in the evaporator of the heat pump system. As the refrigerant evaporates, the heat in the rich amine liquid is transferred to the refrigerant. After the rich amine liquid cools down, it is recirculated to the absorption tower 1. The heated refrigerant is compressed by the compressor to form a high-temperature, high-pressure gas. The high-temperature, high-pressure gas enters the condenser and exchanges heat with the steam condensate from the steam flash tank 20. Through heat exchange with the steam condensate, the heat in the refrigerant is transferred to the steam condensate in the steam flash tank 20, producing steam as a by-product.

[0075] The amine liquid regeneration system includes a regeneration tower 6, a low-pressure condenser 7, a low-pressure reflux tank 8, a low-pressure reflux pump 9, a thermally coupled reboiler 10, a low-pressure tower bottom pump 11, a high-pressure reflux tank 12, a high-pressure reflux pump 13, a reboiler 14, a regeneration compressor 15, a low-pressure flash tank 16, a high-pressure tower bottom pump 17, a lean liquid low-temperature cooler 3, and a steam flash tank 20. A head is provided in the middle of the regeneration tower 6 to divide the regeneration tower 6 into two independent tower bodies, the upper section being a regeneration low-pressure tower and the lower section being a regeneration high-pressure tower. The upper part of the regeneration low-pressure tower is a tray layer, the lower part is a packing layer, and a liquid collector is provided below the packing layer. The upper part of the regeneration high-pressure tower is a tray layer, the lower part is a packing layer, and a liquid collector is provided below the packing layer. A rich liquid inlet is provided on the corresponding tray layer side of the regeneration low-pressure tower. The rich liquid inlet is on the tray. The rich liquid inlet is connected to the rich liquid outlet of the high-temperature lean-rich liquid heat exchanger 4 to pass the rich liquid into the regeneration low-pressure tower. The lower part of the regeneration low-pressure tower is equipped with a thermal coupling reboiler 10. The liquid collected by the liquid collector inside the regeneration low-pressure tower all enters the thermal coupling reboiler 10, and then enters the regeneration low-pressure tower after being heated by the thermal coupling reboiler 10. The top air outlet of the regeneration low-pressure tower is connected to the low-pressure condenser 7 (water-cooled condenser) and the low-pressure reflux tank 8 in sequence. The liquid outlet of the low-pressure reflux tank 8 is connected to the reflux port on the upper part of the regeneration low-pressure tower through a low-pressure reflux pump 9. The air outlet of the low-pressure reflux tank 8 is connected to the off-site acid gas treatment system. The gas outlet of the reflux tank 8 discharges non-condensable acidic gas; the liquid outlet at the bottom of the regeneration low-pressure tower is connected to the lean liquid inlet of the low-temperature lean-rich liquid heat exchanger 5 through the low-pressure tower kettle pump 11, and the lean liquid outlet of the low-temperature lean-rich liquid heat exchanger 5 is connected to the rich liquid circulating liquid pipeline of the absorption tower 1. The lean amine liquid in the tower kettle of the regeneration low-pressure tower is pumped into the low-temperature lean-rich liquid heat exchanger 5 by the low-pressure tower kettle pump 11, and is heat-exchanged with the rich amine liquid discharged from the absorption tower 1, and is sent to the heat pump system 18 after cooling; a rich liquid inlet is provided on the corresponding tower plate layer side of the regeneration high-pressure tower, and the rich liquid inlet is on the tower plate. The rich liquid inlet on the tower side of the regeneration high-pressure tower is connected to the rich liquid outlet of the high-temperature lean-rich liquid heat exchanger 4 to pass the rich amine liquid into the regeneration high-pressure tower, and the lower part of the regeneration high-pressure tower is equipped with a reboiler 14. All the liquid collected by the liquid collector inside the high-pressure tower enters the reboiler 14, is heated by the reboiler 14, and then enters the regenerated high-pressure tower. The reboiler 14 is heated by external steam, and the steam enters the reboiler through the heating medium inlet of the reboiler 14; the heating medium outlet of the reboiler 14 is connected to the inlet of the steam flash tank 20, so that the reboiler steam condensate enters the steam flash tank 20, and the liquid outlet of the steam flash tank 20 is respectively connected to the discharge pipeline and the steam condensate inlet of the heat pump system 18, so that part of the steam condensate is discharged out of the boundary, and the remaining steam condensate enters the heat pump system 18, and the steam outlet of the heat pump system 18 is connected to the heating medium inlet of the reboiler 14. The by-product steam obtained in the heat pump system 18 is circulated to the reboiler 14.

[0076] The gas outlet at the top of the regeneration high-pressure tower is connected to the heat supply medium inlet of the thermal coupling reboiler 10, and the gas phase at the top of the regeneration high-pressure tower is used as the heating heat source of the thermal coupling reboiler 10; the heat supply medium outlet of the thermal coupling reboiler 10 is connected to the inlet of the high-pressure reflux tank 12, the liquid outlet of the high-pressure reflux tank 12 is connected to the reflux port on the top of the regeneration high-pressure tower through the high-pressure reflux pump 13 (the reflux port is lower than the gas outlet at the top of the tower), the gas outlet of the high-pressure reflux tank 12 is connected to the gas inlet on the top of the regeneration low-pressure tower (the gas inlet of the regeneration low-pressure tower is lower than the rich liquid inlet, and the gas inlet of the regeneration low-pressure tower is on the tower plate), and the regenerated high-temperature non-condensable acidic gas of the regeneration high-pressure tower is directly introduced into the regeneration low-pressure tower to strip out the sulfur-containing and carbon-containing gases in the rich amine liquid; the liquid outlet at the bottom of the regeneration high-pressure tower is connected to the low-pressure flash tank 16 The inlet of the regenerated high-pressure tower is connected, and the lean amine liquid in the kettle of the regenerated high-pressure tower enters the low-pressure flash tank 16 through the pressure difference. The liquid outlet of the low-pressure flash tank 16 is connected to the lean liquid inlet of the high-temperature lean-rich liquid heat exchanger 4 through the high-pressure tower kettle pump 17. The lean liquid outlet of the high-temperature lean-rich liquid heat exchanger 4 is connected to the lean liquid inlet of the lean liquid low-temperature cooler 3. The lean liquid outlet of the lean liquid low-temperature cooler 3 is connected to the lean liquid circulation pipeline on the upper part of the absorption tower 1, and the regenerated lean amine liquid is re-introduced into the absorption tower 1; the air outlet of the low-pressure flash tank 16 and the air outlet of the steam flash tank 20 are respectively connected to the inlet of the regeneration compressor 15, and the outlet of the regeneration compressor 15 is connected to the steam inlet of the regeneration high-pressure tower. The flash gas in the low-pressure flash tank 16 and the steam flash tank 20 passes through the regeneration compressor 15 and directly enters the regeneration high-pressure tower to heat the kettle amine liquid. Example 2

[0077] The desulfurization and decarbonization system according to Example 1 desulfurizes and decarbonizes the sulfur- and carbon-containing raw gas, comprising the following steps:

[0078] Step (1): Raw gas from the external pipeline network (temperature: 42°C, pressure: 15 kPa, CO2 content: 22% mol, COS content: 150 mg / Nm 3 , H2S content: 40mg / Nm 3 ) enters absorption tower 1 (filler: 125Y corrugated packing, pressure: 15kPa) from the lower air inlet. Amine liquid (a mixed aqueous solution of N-methyldiethanolamine, methylethanolamine, 2,5-hydroxypiperazine, and vanadium pentoxide, N-methyldiethanolamine: 40wt%, methylethanolamine: 3wt%, 2,5-hydroxypiperazine: 0.5wt%, vanadium pentoxide: 0.2wt%; temperature: 32°C) is introduced into absorption tower 1 from the upper lean liquid inlet. The gas-liquid ratio of the absorption tower top circulation volume is controlled at 800, and the gas-liquid ratio of the bottom circulation volume is controlled at 180. Within absorption tower 1, the feed gas and amine liquid come into countercurrent contact. The acidic gases in the feed gas are absorbed by the amine liquid to form amino salt compounds. Purified gas (temperature: 50°C, CO2 content: 0.3% mol, total sulfur content: 12 mg / Nm3) is discharged from the top gas outlet of the absorption tower.3 ), the lean amine liquid at the top of the absorption tower is collected by a liquid collector, and the lean amine liquid is transported to the top of the absorption tower through a lean liquid circulation pump 19 and a lean liquid circulation pipeline; the liquid collected by the liquid collector overflows to the lower part of the lower absorption tower, and is further countercurrently contacted with the feed gas to obtain rich amine liquid in the bottom of the absorption tower 1. The rich amine liquid in the bottom of the absorption tower (acid gas load mol / mol amine: 30; temperature: 65°C) passes through the rich liquid pump 2, and a part of the rich amine liquid enters the heat pump system 18. The rich amine liquid exchanges heat with the refrigerant R-454B in the evaporator of the heat pump system. By evaporating the refrigerant, the heat in the rich amine liquid is transferred to the refrigerant, and the rich amine liquid is cooled to 40°C and recycled to the absorption tower 1. The refrigeration after heating The refrigerant is compressed by the compressor to form a high-temperature, high-pressure gas, which enters the condenser and exchanges heat with the steam condensate from the steam flash tank 20. Through the heat exchange with the steam condensate, the heat in the refrigerant is transferred to the steam condensate in the steam flash tank 20 to produce steam as a by-product; the other part of the rich amine liquid enters the low-temperature rich-lean liquid heat exchanger 5 and the high-temperature rich-lean liquid heat exchanger 4 in sequence. In the low-temperature rich-lean liquid heat exchanger 5, the rich amine liquid exchanges heat with the lean amine liquid regenerated in the regeneration low-pressure tower and is heated to 85°C. In the high-temperature rich-lean liquid heat exchanger 4, the rich amine liquid exchanges heat with the lean amine liquid discharged from the low-pressure flash tank 16 and is heated to 95°C. The rich amine liquid after heat exchange enters the regeneration low-pressure tower and the regeneration high-pressure tower of the regeneration tower 6 at the same time;

[0079] Step (2): The rich amine liquid enters the regeneration low-pressure tower (filler: 250Y corrugated packing, tower plate: float valve tower plate, temperature: 107 ° C, pressure: 21 kPa), and contacts with the non-condensable acid gas from the high-pressure reflux tank 12 in countercurrent, and then passes through the thermal coupling reboiler 10 (K-type kettle reboiler) for heating, and the amino salt compound decomposes to obtain amine liquid and acid gas. The regenerated acid gas enters the low-pressure condenser 7 (temperature: 35 ° C, pressure: The condensate and acid gases enter the low-pressure reflux tank 8. The condensate is refluxed back into the tower via the low-pressure reflux pump 9. The non-condensable acid gases are discharged from the low-pressure reflux tank 8 to the outside for acid gas treatment. The regenerated low-pressure tower bottom lean amine liquid (acid gas load mol / mol amine: 4) is pumped by the low-pressure tower bottom pump 11 into the low-temperature lean-rich liquid heat exchanger 5 for heat exchange with the rich amine liquid from the adsorption tower 1. The liquid is then combined with the rich amine liquid from the absorption tower 1 and enters the heat pump system 18.

[0080] The rich amine liquid enters the regeneration high-pressure tower (packing: 250Y corrugated packing, tower tray: float valve tray, temperature: 127°C, pressure: 120 kPa), is steam-heated in the reboiler 14 (K-type kettle reboiler), and the amino salt compound is decomposed to produce amine liquid and acid gas. The regenerated acid gas enters the thermally coupled reboiler 10 (temperature: 125°C, pressure: 120 kPa) from the top of the tower as a heating source for the regeneration low-pressure tower. The regenerated acid gas is condensed to produce condensate and acid gas. The condensate and acid gas enter the high-pressure reflux tank 12. The condensate is refluxed from the top to the regeneration high-pressure tower through the high-pressure reflux pump 13. The non-condensable acid gas (temperature: 127°C) is discharged from the high-pressure reflux tank 12 and enters the regeneration low-pressure tower from the air inlet of the regeneration low-pressure tower. The non-condensable acid gas countercurrently contacts the rich amine liquid entering the regeneration low-pressure tower, and the sulfur- and carbon-containing gases in the rich amine liquid are stripped out.

[0081] The lean amine liquid in the regeneration high-pressure tower kettle enters the low-pressure flash tank 16 (pressure: 0 kPa). The acid gas after flashing is compressed by the regeneration compressor 15 and returned to the regeneration high-pressure tower kettle. The lean amine liquid (acid gas load mol / mol amine: 5) is pumped by the high-pressure tower kettle pump 17 into the high-temperature lean-rich liquid heat exchanger 4 and the lean liquid low-temperature cooler 3 (water-cooled cooler, temperature: 32°C) in sequence to exchange heat with the rich amine liquid and circulating water respectively, and is cooled to 32°C. It then enters the absorption tower 1 through the lean liquid inlet;

[0082] The steam condensate from the reboiler 14 enters the steam flash tank 20 (temperature: 100°C, pressure: 0 kPa). The flash gas is compressed by the regeneration compressor 15 and then returned to the regeneration high-pressure tower kettle. Part of the steam condensate is discharged to the outside, and part of the steam condensate is recovered to the heat pump system 18 to exchange heat with the high-temperature, high-pressure gas compressed by the refrigerant in the compressor, producing low-pressure steam (temperature: 140°C) as a by-product, and then the steam is circulated to the reboiler 14. Example 3

[0083] The desulfurization and decarbonization system according to Example 1 desulfurizes and decarbonizes the sulfur- and carbon-containing raw gas, comprising the following steps:

[0084] Step (1): Raw gas from the external pipeline network (temperature: 42°C, pressure: 15 kPa, CO2 content: 22% mol, COS content: 150 mg / Nm 3 , H2S content: 40mg / Nm 3) enters absorption tower 1 (filler: 125Y corrugated packing, pressure: 10kPa) from the lower air inlet. Amine liquid (a mixed aqueous solution of N-methyldiethanolamine, methylethanolamine, 2,5-hydroxypiperazine, and vanadium pentoxide, N-methyldiethanolamine: 38wt%, methylethanolamine: 3wt%, 2,5-hydroxypiperazine: 0.5wt%, vanadium pentoxide: 0.2wt%; temperature: 40°C) is introduced into the absorption tower from the upper lean liquid inlet. The gas-liquid ratio of the absorption tower top circulation volume is controlled at 800, and the gas-liquid ratio of the bottom circulation volume is controlled at 150. Within absorption tower 1, the feed gas and amine liquid come into countercurrent contact. The acidic gases in the feed gas are absorbed by the amine liquid to form amino salt compounds. Purified gas (temperature: 58°C, CO2 content: 0.5% mol, total sulfur content: 18 mg / Nm3) is discharged from the top gas outlet of the absorption tower. 3 ), the lean amine liquid at the top of the absorption tower is collected by a liquid collector, and the lean amine liquid is transported to the top of the absorption tower through a lean liquid circulation pump 19 and a lean liquid circulation pipeline; the liquid collected by the liquid collector overflows to the lower part of the lower absorption tower, and is further countercurrently contacted with the feed gas to obtain rich amine liquid in the bottom of the absorption tower 1. The rich amine liquid in the bottom of the absorption tower (acid gas load mol / mol amine: 29; temperature: 48°C) passes through the rich liquid pump 2, and a part of the rich amine liquid enters the heat pump system 18. The rich amine liquid exchanges heat with the refrigerant R-454B in the evaporator of the heat pump system. By evaporating the refrigerant, the heat in the rich amine liquid is transferred to the refrigerant, and the rich amine liquid is cooled to 40°C and recycled to the absorption tower 1. The heated product The refrigerant is compressed by the compressor to form a high-temperature, high-pressure gas. The high-temperature, high-pressure gas enters the condenser and exchanges heat with the steam condensate from the steam flash tank 20. Through the heat exchange with the steam condensate, the heat in the refrigerant is transferred to the steam condensate in the steam flash tank 20 to produce steam as a by-product; the other part of the rich amine liquid enters the low-temperature rich-lean liquid heat exchanger 5 and the high-temperature rich-lean liquid heat exchanger 4 in sequence. In the low-temperature rich-lean liquid heat exchanger 5, the rich amine liquid exchanges heat with the lean amine liquid regenerated from the regeneration low-pressure tower and is heated to 88°C. In the high-temperature rich-lean liquid heat exchanger 4, the rich amine liquid exchanges heat with the lean amine liquid discharged from the low-pressure flash tank 16 and is heated to 98°C. The rich amine liquid after heat exchange enters the regeneration low-pressure tower and the regeneration high-pressure tower of the regeneration tower 6 at the same time;

[0085] Step (2): the rich amine liquid enters the regeneration low-pressure tower (filler: 250Y corrugated packing, tower plate: float valve tower plate, temperature: 110°C, pressure: 25kPa), contacts with the non-condensable acid gas from the high-pressure reflux tank 12 in countercurrent, and then passes through the thermal coupling reboiler 10 (K-type kettle reboiler) for heating, the amino salt compound decomposes to obtain amine liquid and acid gas, the regenerated acid gas enters the low-pressure condenser 7 (temperature: 38°C, pressure: 25kPa) from the top of the tower for condensation, the condensate and the acid gas enter the low-pressure reflux tank 8, the condensate is refluxed back to the tower through the low-pressure reflux pump 9, and the non-condensable acid gas is discharged from the low-pressure reflux tank 8 to the outside for acid gas treatment; the lean amine liquid in the regeneration low-pressure tower kettle (acid gas load mol / mol amine: 4) is pumped into the low-temperature lean-rich liquid heat exchanger 5 by the low-pressure tower kettle pump 11, and merged with the rich amine liquid from the absorption tower 1 to enter the heat pump system 18;

[0086] The rich amine liquid enters the regeneration high-pressure tower (packing: 250Y corrugated packing, tower plate: float valve tower plate, temperature: 130℃, pressure: 125kPa), passes through the reboiler 14 (K-type kettle reboiler) for steam heating, and the amino salt compound decomposes to produce amine liquid and acid gas. The regenerated acid gas enters the thermal coupling reboiler 10 (temperature: 128℃, pressure: 125kPa) from the top of the tower as a heating source for the regeneration low-pressure tower. The regenerated acid gas condenses to produce condensate and acid gas. The condensate and acid gas enter the high-pressure reflux tank 12. The condensate is refluxed back into the tower through the high-pressure reflux pump 13. The non-condensable acid gas is discharged from the high-pressure reflux tank 12 and enters the regeneration low-pressure tower from the air inlet of the regeneration low-pressure tower. The non-condensable acid gas countercurrently contacts the rich amine liquid entering the regeneration low-pressure tower, and the sulfur-containing and carbon-containing gases in the rich amine liquid are stripped out.

[0087] The lean amine liquid in the regeneration high-pressure tower kettle enters the low-pressure flash tank 16 (pressure: 5kPa). The acid gas after flashing is compressed by the regeneration compressor 15 and then returns to the regeneration high-pressure tower kettle. The lean amine liquid (acid gas load mol / mol amine: 4) is pumped into the high-temperature lean-rich liquid heat exchanger 4 and the lean liquid low-temperature cooler 3 (water-cooled cooler, temperature: 40°C) by the high-pressure tower kettle pump 17 in sequence to exchange heat with the rich amine liquid and circulating water respectively, and is cooled to 40°C. It then enters the absorption tower 1 through the lean liquid inlet;

[0088] The steam condensate from the reboiler 14 enters the steam flash tank 20 (temperature: 101°C, pressure: 5 kPa). The flash gas is compressed by the regeneration compressor 15 and then returned to the regeneration high-pressure tower kettle. Part of the steam condensate is discharged to the outside, and part of the steam condensate is recovered to the heat pump system 18 to exchange heat with the high-temperature, high-pressure gas compressed by the compressor by the refrigerant. The by-product low-pressure steam (temperature: 140°C) is circulated to the reboiler 14. Example 4

[0089] The desulfurization and decarbonization system according to Example 1 desulfurizes and decarbonizes the sulfur- and carbon-containing raw gas, comprising the following steps:

[0090] Step (1): Raw gas from the external pipeline (temperature: 53°C, pressure: 6 kPa, CO2 content: 22% mol, COS content: 150 mg / Nm 3 , H2S content: 40mg / Nm 3 ) enters absorption tower 1 (filler: 125Y corrugated packing, pressure: 6 kPa) from the lower air inlet. Amine liquid (a mixed aqueous solution of N-methyldiethanolamine, methylethanolamine, 2,5-hydroxypiperazine, and vanadium pentoxide, N-methyldiethanolamine: 38 wt%, methylethanolamine: 2 wt%, 2,5-hydroxypiperazine: 0.5 wt%, vanadium pentoxide: 0.2 wt%; temperature: 43°C) is introduced into the absorption tower from the upper lean liquid inlet. The gas-liquid ratio of the absorption tower top circulation volume is controlled at 800, and the gas-liquid ratio of the bottom circulation volume is controlled at 110. Within absorption tower 1, the feed gas and amine liquid come into countercurrent contact. The acidic gases in the feed gas are absorbed by the amine liquid to form amino salt compounds. Purified gas (temperature: 59°C, CO2 content: 0.5% mol, total sulfur content: 20 mg / Nm3) is discharged from the top gas outlet of the absorption tower. 3 ), the lean amine liquid at the top of the absorption tower is collected by a liquid collector, and the lean amine liquid is transported to the top of the absorption tower through a lean liquid circulation pump 19 and a lean liquid circulation pipeline; the liquid collected by the liquid collector overflows to the lower part of the lower absorption tower, and is further countercurrently contacted with the feed gas to obtain rich amine liquid in the bottom of the absorption tower 1. The rich amine liquid in the bottom of the absorption tower (acid gas load mol / mol amine: 27; temperature: 60°C) passes through the rich liquid pump 2, and a part of the rich amine liquid enters the heat pump system 18. The rich amine liquid exchanges heat with the refrigerant R-454B in the evaporator of the heat pump system. By evaporating the refrigerant, the heat in the rich amine liquid is transferred to the refrigerant, and the rich amine liquid is cooled to 42°C and recycled to the absorption tower 1. The refrigeration after heating The refrigerant is compressed by the compressor to form a high-temperature, high-pressure gas, which enters the condenser and exchanges heat with the steam condensate from the steam flash tank 20. Through the heat exchange with the steam condensate, the heat in the refrigerant is transferred to the steam condensate in the steam flash tank 20 to produce steam as a by-product; the other part of the rich amine liquid enters the low-temperature rich-lean liquid heat exchanger 5 and the high-temperature rich-lean liquid heat exchanger 4 in sequence. In the low-temperature rich-lean liquid heat exchanger 5, the rich amine liquid exchanges heat with the lean amine liquid regenerated in the regeneration low-pressure tower and is heated to 85°C. In the high-temperature rich-lean liquid heat exchanger 4, the rich amine liquid exchanges heat with the lean amine liquid discharged from the low-pressure flash tank 16 and is heated to 95°C. The rich amine liquid after heat exchange then enters the regeneration low-pressure tower and the regeneration high-pressure tower of the regeneration tower 6 at the same time;

[0091] Step (2): the rich amine liquid enters the regeneration low-pressure tower (filler: 250Y corrugated packing, tower plate: float valve tower plate, temperature: 104°C, pressure: 20kPa), contacts with the non-condensable acid gas from the high-pressure reflux tank 12 in countercurrent, and then passes through the thermal coupling reboiler 10 (K-type kettle reboiler) for heating, the amino salt compound decomposes to obtain amine liquid and acid gas, the regenerated acid gas enters the low-pressure condenser 7 (temperature: 40°C, pressure: 20kPa) from the top of the tower for condensation, the condensate and the acid gas enter the low-pressure reflux tank 8, the condensate is refluxed to the regeneration low-pressure tower through the low-pressure reflux pump 9, and the non-condensable acid gas is discharged from the low-pressure reflux tank 8 to the outside for acid gas treatment; the lean amine liquid in the regeneration low-pressure tower kettle (acid gas load mol / mol amine: 3) is pumped into the low-temperature lean-rich liquid heat exchanger 5 by the low-pressure tower kettle pump 11, and merged with the rich amine liquid from the absorption tower 1 to enter the heat pump system 18;

[0092] The rich amine liquid enters the regeneration high-pressure tower (packing: 250Y corrugated packing, tower plate: float valve tower plate, temperature: 124°C, pressure: 120kPa), is steam-heated in the reboiler 14 (K-type kettle reboiler), and the amino salt compound is decomposed to produce amine liquid and acid gas. The regenerated acid gas enters the thermal coupling reboiler 10 (temperature: 122°C, pressure: 120kPa) from the top of the tower as a heating source for the regeneration low-pressure tower. The regenerated acid gas is condensed to produce condensate and acid gas. The condensate and acid gas enter the high-pressure reflux tank 12. The condensate is refluxed into the regeneration high-pressure tower through the high-pressure reflux pump 13. The non-condensable acid gas is discharged from the high-pressure reflux tank 12 and enters the regeneration low-pressure tower from the air inlet of the regeneration low-pressure tower. The non-condensable acid gas countercurrently contacts the rich amine liquid entering the regeneration low-pressure tower, and the sulfur- and carbon-containing gases in the rich amine liquid are stripped out.

[0093] The lean amine liquid in the regeneration high-pressure tower kettle enters the low-pressure flash tank 16 (pressure: 20kPa). The acid gas after flashing is compressed by the regeneration compressor 15 and then returns to the regeneration high-pressure tower kettle. The lean amine liquid (acid gas load mol / mol amine: 5) is pumped into the high-temperature lean-rich liquid heat exchanger 4 and the lean liquid low-temperature cooler 3 (water-cooled cooler, temperature: 43°C) by the high-pressure tower kettle pump 17 in sequence to exchange heat with the rich amine liquid and circulating water respectively, and is cooled to 43°C. It then enters the absorption tower 1 through the lean liquid inlet;

[0094] The steam condensate from the reboiler 14 enters the steam flash tank 20 (temperature: 104.5°C, pressure: 20 kPa), and the flash gas is compressed by the regeneration compressor 15 and returned to the regeneration high-pressure tower kettle. Part of the steam condensate is discharged to the outside, and part of the steam condensate is recovered to the heat pump system 18 as a by-product low-pressure steam (temperature: 140°C), which is exchanged with the high-temperature, high-pressure gas compressed by the compressor and circulated to the reboiler 14. Example 5

[0095] The test was conducted using a 400,000-ton CCUS device from a thermal power plant. The flue gas temperature was 42°C, the pressure was 15kPa, the CO2 content was 22% mol, and the COS content was 150 mg / Nm 3 , H2S content: 40mg / Nm 3 .

[0096] The original process of the 400,000-ton CCUS unit adopted a single-stage absorption tower plus a single-stage regeneration tower system.

[0097] The energy consumption of the decarbonization and desulfurization devices of the original process and the process of the present invention (taking Example 2 as an example) is shown in Table 2.

[0098] Table 2. Comparison of energy consumption of decarbonization and desulfurization equipment in the original process and the process of the present invention

[0099]

Claims

1. A desulfurization and decarbonization system, characterized by: include: Flue gas absorption system, amine liquid regeneration system; The flue gas absorption system includes an absorption tower, a high-temperature lean-rich liquid heat exchanger, a low-temperature lean-rich liquid heat exchanger, and a heat pump system; an air inlet is provided at the lower part of the absorption tower, which is connected to the raw gas pipeline to allow the raw gas to enter the absorption tower from the lower part; an air outlet is provided at the top of the absorption tower, and purified gas is discharged from the air outlet; a lean liquid inlet is provided at the upper part of the absorption tower, a rich liquid outlet is provided at the bottom, and a liquid collector is provided in the middle of the absorption tower. The liquid at the upper part of the absorption tower overflows from the liquid collector into the lower part, and the gas at the lower part enters the upper part through the liquid collector. A rich liquid circulation inlet is provided in the middle below the liquid collector; a lean liquid outlet is provided in the middle of the absorption tower, the lean liquid outlet is connected to the lean liquid inlet via a lean liquid circulation pipeline, and the liquid collected by the liquid collector is circulated to the absorption tower via a lean liquid circulation pipeline outside the tower; a discharge pipeline and a rich liquid circulation pipeline are provided in parallel at the rich liquid outlet at the bottom of the absorption tower, the discharge pipeline is connected to the rich liquid inlet of the amine liquid regeneration system in sequence via a low-temperature lean-rich liquid heat exchanger and a high-temperature lean-rich liquid heat exchanger, and the rich liquid circulation pipeline is connected to the rich liquid circulation inlet via a heat pump system; The amine liquid regeneration system includes a regeneration tower, a low-pressure condenser, a low-pressure reflux tank, a thermally coupled reboiler, a high-pressure reflux tank, a reboiler, a low-pressure flash tank, a lean liquid low-temperature cooler, and a steam flash tank; the regeneration tower includes an upper regeneration low-pressure tower and a lower regeneration high-pressure tower; the upper part of the regeneration low-pressure tower is a tray layer, the lower part is a packing layer, and a liquid collector is provided below the packing layer; the rich liquid inlet on the tower side of the regeneration low-pressure tower is connected to the rich liquid outlet of the high-temperature lean-rich liquid heat exchanger, the lower part of the regeneration low-pressure tower is equipped with a thermally coupled reboiler, the top gas outlet of the regeneration low-pressure tower is connected to the low-pressure condenser and the low-pressure reflux tank in sequence, and the liquid outlet of the low-pressure reflux tank is connected to the reflux port on the upper part of the regeneration low-pressure tower; the bottom liquid outlet of the regeneration low-pressure tower is connected to the rich liquid outlet of the high-temperature lean-rich liquid heat exchanger through the low-temperature lean-rich liquid heat exchanger. The regeneration high-pressure tower is connected to the liquid circulation pipeline; the upper part of the regeneration high-pressure tower is a tower plate layer, the lower part is a packing layer, and a liquid collector is provided below the packing layer; the rich liquid inlet of the regeneration high-pressure tower side is connected to the rich liquid outlet of the high-temperature lean-rich liquid heat exchanger, the lower part of the regeneration high-pressure tower is equipped with a reboiler, the top gas outlet of the regeneration high-pressure tower is connected to the heating medium inlet of the thermal coupling reboiler, and the gas phase at the top of the regeneration high-pressure tower is used as the heating heat source of the thermal coupling reboiler; the heating medium outlet of the thermal coupling reboiler is connected to the inlet of the high-pressure reflux tank, the liquid outlet of the high-pressure reflux tank is connected to the reflux port on the upper part of the regeneration high-pressure tower, and the gas outlet of the high-pressure reflux tank is connected to the gas inlet on the upper part of the regeneration low-pressure tower, and the sulfur-containing and carbon-containing gases in the rich amine liquid are stripped out by directly passing the regenerated high-temperature gas of the regeneration high-pressure tower into the regeneration low-pressure tower; The bottom liquid outlet of the regeneration high-pressure tower is connected to the inlet of the low-pressure flash tank, and the liquid outlet of the low-pressure flash tank is connected to the lean liquid circulation pipeline of the absorption tower through the high-temperature lean-rich liquid heat exchanger and the lean liquid low-temperature cooler in sequence, so that the regenerated lean amine liquid is passed into the absorption tower; The heating medium outlet of the reboiler is connected to the inlet of the steam flash tank, so that the steam condensate discharged from the reboiler enters the steam flash tank. The liquid outlet of the steam flash tank is respectively connected to the discharge pipeline and the steam condensate inlet of the heat pump system, so that part of the steam condensate is discharged out of the boundary, and the remaining steam condensate enters the heat pump system. The steam outlet of the heat pump system is connected to the heating medium inlet of the reboiler, and the steam obtained in the heat pump system is circulated to the reboiler.

2. The desulfurization and decarbonization system according to claim 1, characterized in that: A lean liquid circulation pump is provided on the lean liquid circulation pipeline; a rich liquid pump is provided at the rich liquid outlet of the absorption tower; a discharge pipeline and a rich liquid circulation pipeline are provided in parallel at the outlet of the rich liquid pump, and the discharge pipeline is connected to the rich liquid inlet of the low-temperature lean and rich liquid heat exchanger.

3. The desulfurization and decarbonization system according to claim 1, characterized in that: A packing layer is provided at the upper and lower parts of the absorption tower respectively; the packing used in the absorption tower is a structured packing, and the packing is selected from BX, CY wire mesh packing, or 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y plate corrugated packing; The tray of the regeneration low-pressure tower is a sieve plate, a float valve or a bubble cap; the packing of the regeneration low-pressure tower is a BX or CY wire mesh packing, or a 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X or 750Y plate corrugated packing; The tower plates in the regeneration high-pressure tower are sieve plates, float valves or bubble caps; the fillers in the regeneration high-pressure tower are BX, CY wire mesh fillers, or 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y plate corrugated fillers.

4. The desulfurization and decarbonization system according to claim 1, characterized in that: The liquid outlet of the low-pressure reflux tank is provided with a low-pressure reflux pump, and the outlet of the low-pressure reflux pump is connected to the reflux port on the upper part of the regeneration low-pressure tower; The liquid outlet of the regeneration low-pressure tower is provided with a low-pressure tower kettle pump, the outlet of the low-pressure tower kettle pump is connected to the lean liquid inlet of the low-temperature lean-rich liquid heat exchanger, and the lean liquid outlet of the low-temperature lean-rich liquid heat exchanger is connected to the rich liquid circulation pipeline; The liquid outlet of the high-pressure reflux tank is provided with a high-pressure reflux pump, and the outlet of the high-pressure reflux pump is connected to the reflux port on the upper part of the regeneration high-pressure tower; The liquid outlet of the low-pressure flash tank is provided with a high-pressure tower kettle pump, the outlet of the high-pressure tower kettle pump is connected to the lean liquid inlet of the high-temperature lean-rich liquid heat exchanger, the lean liquid outlet of the high-temperature lean-rich liquid heat exchanger is connected to the lean liquid inlet of the lean liquid low-temperature cooler, and the lean liquid outlet of the lean liquid low-temperature cooler is connected to the lean liquid circulation pipeline of the absorption tower.

5. The desulfurization and decarbonization system according to claim 1, characterized in that: The amine liquid regeneration system also includes a regeneration compressor; the gas outlet of the low-pressure flash tank and the gas outlet of the steam flash tank are respectively connected to the inlet of the regeneration compressor, and the outlet of the regeneration compressor is connected to the steam inlet of the regeneration high-pressure tower.

6. A method for desulfurization and decarbonization based on the system according to claim 1, characterized in that: The steps include: Step (1): the raw gas enters the absorption tower from the bottom, and the amine liquid enters the absorption tower from the top. In the absorption tower, the amine liquid contacts the raw gas in a countercurrent manner, absorbs the acidic gas in the raw gas to generate amino salt compounds, and the purified gas is discharged from the absorption tower from the top of the tower. The lean amine liquid collected by the liquid collector is returned to the absorption tower through the lean liquid circulation pipeline outside the tower. Rich amine liquid is obtained in the absorption tower kettle. A part of the rich amine liquid is sent to the heat pump system through the rich liquid circulation pipeline, and heat is transferred to the steam condensate from the steam flash tank through the intermediate medium. The cooled rich amine liquid enters the absorption tower again, and the remaining rich amine liquid enters the low-temperature lean-rich liquid heat exchanger and the high-temperature lean-rich liquid heat exchanger in turn. In the low-temperature lean-rich liquid heat exchanger, the rich amine liquid exchanges heat with the lean amine liquid regenerated from the regeneration low-pressure tower. In the high-temperature lean-rich liquid heat exchanger, the rich amine liquid exchanges heat with the lean amine liquid discharged from the low-pressure flash tank. The heated rich amine liquid enters the regeneration low-pressure tower and the regeneration high-pressure tower at the same time. Step (2): The rich amine liquid enters the regeneration low-pressure tower, is heated by a thermally coupled reboiler, and the amino salt compound is decomposed to obtain amine liquid and acid gas. The regeneration gas containing acid gas is discharged from the top of the regeneration low-pressure tower, condensed by a low-pressure condenser, and enters the low-pressure reflux tank. The condensate is refluxed to the regeneration low-pressure tower; The lean amine liquid in the kettle of the regenerated low-pressure tower enters the low-temperature lean-rich liquid heat exchanger, exchanges heat with the rich amine liquid discharged from the absorption tower, and is sent to the heat pump system after cooling. The cooled rich amine liquid is then returned to the absorption tower; The rich amine liquid enters the regeneration high-pressure tower and is heated by steam in the reboiler. The amino salt compounds are decomposed to produce amine liquid and acid gas. The regeneration gas containing acid gas is discharged from the top of the regeneration high-pressure tower and enters the thermally coupled reboiler as a heat source for the regeneration low-pressure tower. The regeneration gas is condensed, and the condensate and acid gas enter the high-pressure reflux tank. The liquid returns to the regeneration high-pressure tower. The non-condensable acid gas is discharged from the high-pressure reflux tank to the regeneration low-pressure tower for stripping out the sulfur-containing and carbon-containing gases in the rich amine liquid; the lean amine liquid in the bottom of the regeneration high-pressure tower enters the low-pressure flash tank through the pressure difference, and the lean amine liquid in the low-pressure flash tank is cooled in turn through the high-temperature rich-lean liquid heat exchanger and the lean liquid low-temperature cooler, and enters the absorption tower; the steam condensate discharged from the reboiler enters the steam flash tank, part of the condensate in the steam flash tank is discharged outside the boundary, and part enters the heat pump system to produce steam and is recycled to the reboiler.

7. The desulfurization and decarbonization method according to claim 6, characterized in that: In step (1), the pressure of the raw gas is 0-300 kPa; the content of CO2 in the raw gas is 5-30 mol%, and the content of COS is 10-300 mg / Nm 3 , the content of H2S is 10~150mg / Nm 3 ; CO2≤0.5 mol%, total sulfur≤20mg / Nm 3 .

8. The method for desulfurization and decarbonization according to claim 6, characterized in that: In step (1), the operating pressure of the absorption tower is consistent with the feed gas inlet pressure; the operating temperature of the absorption tower top is 40-70°C; the operating temperature of the absorption tower kettle is 45-80°C; The gas-liquid ratio of the bottom circulation volume of the absorption tower is 100-800, and the gas-liquid ratio of the top circulation volume is 500-1500; The temperature of the rich liquid inlet of the heat pump system is 45-80°C; the temperature of the rich liquid outlet of the heat pump system is 35-55°C; In step (2), the operating pressure of the regeneration low-pressure tower is 20-80 kPa; the operating temperature of the regeneration low-pressure tower is 104-120°C; The operating temperature of the low-pressure condenser is 30-50°C; The operating pressure of the regeneration high-pressure tower is 100-200 kPa; the operating temperature of the regeneration high-pressure tower is 124-140°C; The operating temperature of the lean liquid cryogenic cooler is 20-50°C; The operating pressure of the low-pressure flash tank is -20 to 50 kPa; The operating pressure of the steam flash tank is -10 to 60 kPa; The temperature of the steam condensate inlet of the heat pump system is 96-113°C; The temperature of the steam outlet of the heat pump system is 125-150°C.

9. The desulfurization and decarbonization method according to claim 8, characterized in that: In step (1), the operating temperature of the absorption tower top is 40-60°C; the operating temperature of the absorption tower kettle is 48-70°C; The gas-liquid ratio of the bottom circulation volume of the absorption tower is 110-400, and the gas-liquid ratio of the top circulation volume is 800-1100; The temperature of the rich liquid inlet of the heat pump system is 48-70°C; the temperature of the rich liquid outlet of the heat pump system is 35-45°C; In step (2), the operating pressure of the regeneration low-pressure tower is 20-50 kPa; the operating temperature of the regeneration low-pressure tower is 104-115°C; The operating temperature of the low-pressure condenser is 32-42°C; The operating pressure of the regeneration high-pressure tower is 120-150 kPa; the operating temperature of the regeneration high-pressure tower is 124-135°C; The operating temperature of the lean liquid cryogenic cooler is 25-43°C; The operating pressure of the low-pressure flash tank is 0-20 kPa; The operating pressure of the steam flash tank is 0-20 kPa; The temperature of the steam condensate inlet of the heat pump system is 100-105°C; The temperature of the steam outlet of the heat pump system is 130-145°C.

10. The desulfurization and decarbonization method according to claim 6, characterized in that: The acid gas obtained after flash evaporation in the low-pressure flash tank is compressed by the regeneration compressor and then enters the regeneration high-pressure tower; the flash gas obtained after flash evaporation in the steam flash tank is compressed by the regeneration compressor and then enters the regeneration high-pressure tower.

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