Desulfurization and decarburization method and system

Abstract

The invention belongs to the field of environment-friendly gas purification and energy conservation, and discloses a desulfurization and decarbonization method and system. The desulfurization and decarbonization system comprises a flue gas absorption system and an amine liquid regeneration system, the flue gas regeneration system comprises an absorption tower, a high-temperature rich and lean liquid heat exchanger, a low-temperature rich and lean liquid heat exchanger and a heat pump system; the amine liquid regeneration system comprises a regeneration tower, a thermal coupling reboiler, a high-pressure reflux tank, a reboiler, a low-pressure flash tank, a barren liquor low-temperature cooler and a steam flash tank. The desulfurization and decarbonization method comprises the following steps: in an absorption tower, performing countercurrent contact on amine liquid and raw material gas, and absorbing acid gas in the raw material gas to generate an amino salt compound, so as to obtain amine-rich liquid; the amine-rich liquid enters a regeneration low-pressure tower and a regeneration high-pressure tower, the amino salt compound is regenerated to release acid gas to generate amine liquid, and the amine liquid returns to the absorption tower. By utilizing a high-low pressure regenerative thermal coupling technology and a heat pump technology, the energy consumption of the system is effectively reduced, the overall absorption efficiency is improved, and the equipment investment and site arrangement are saved.

Description

Technical Field

[0001] The present invention belongs to the field of environmental protection gas purification and energy saving, and relates to a method and system for desulfurization and decarbonization, and 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] Industrial exhaust gas generally contains harmful substances such as carbon dioxide (CO2), sulfur dioxide (SO2), and organic sulfur, which need to be removed before discharge.

[0003] Carbon dioxide is a type of greenhouse gas. When the carbon dioxide content in the atmosphere increases, it will absorb more solar long-wave radiation, causing the earth's temperature to rise, and eventually leading to the melting of glaciers in the Arctic and Antarctic, rising sea levels, and frequent extreme weather such as floods, droughts, extreme cold and heat. When sulfur dioxide is emitted into the atmosphere, it will oxidize into sulfuric acid mist or sulfate aerosol to form acid rain, causing environmental acidification.

[0004] At present, the commonly used decarbonization and desulfurization method is mainly the amine method, which selectively removes acidic substances such as carbon dioxide, sulfur dioxide, and organic sulfur by using different types of alkyl alcohol amine compounds. Alkyl alcohol amine compounds react with acidic gases to form amino salt compounds, which decompose at high temperatures to release acidic gases. The regenerated alkyl alcohol amine compounds are used to continue to absorb acidic gases. However, amino salt compounds need to absorb a large amount of heat to decompose during the regeneration process, resulting in high energy consumption of the system, and generally amino salt compounds are highly corrosive to equipment and prone to scaling. Therefore, it is urgent to develop a type of low-corrosion, non-scaling, environmentally friendly absorption liquid and low-energy consumption desulfurization and decarbonization process.

[0005] Patent application CN117070256A adopts a two-tower absorption regeneration process, which consumes a lot of steam and circulating water and has high system energy consumption. The regeneration tower only has a stripping section but no rectification section, and the amine liquid is easily taken out of the top of the tower, resulting in a large loss. The fresh amino salt compounds on the packing in the regeneration tower fall directly into the tower bottom and are not separated from the regenerated amine liquid. The retention regeneration time of the amino salt compounds cannot be guaranteed, resulting in the amino salt compounds being directly discharged to 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 reduce energy consumption to the greatest extent.

[0007] The purpose of the present invention is achieved through the following technical solutions: A desulfurization and decarbonization system, comprising: a flue gas absorption system, an amine liquid regeneration system; The flue gas regeneration system comprises 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 part of the absorption tower 1, and the air inlet is connected to the raw gas pipeline to pass the raw gas into the absorption tower from the lower part; an air outlet is provided at the top of the absorption tower 1, and the air outlet is connected to the purified gas pipeline to discharge the purified gas from the air outlet; a lean liquid inlet is provided at the upper part of the absorption tower 1, and a rich liquid outlet is provided at the bottom; a liquid collector is provided in the middle part of the absorption tower 1, and the liquid at the upper part of the absorption tower 1 overflows from the liquid collector into the lower part, and the gas at the lower part is discharged through the liquid collector. The collector enters the upper part, and a rich liquid circulation inlet is provided in the middle part 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, and the liquid collected by the liquid collector (i.e. lean amine liquid) is circulated to the absorption tower 1 through a 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 through a low-temperature lean-rich liquid heat exchanger 5 and a high-temperature lean-rich liquid heat exchanger 4 in turn, and the rich liquid circulation channel is connected to the rich liquid circulation inlet through a heat pump system 18; The amine liquid regeneration system comprises 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 comprises an upper regeneration low-pressure tower and a lower regeneration high-pressure tower; the upper part of the regeneration low-pressure tower is a plate 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 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-rich liquid heat exchanger 4 through the low-temperature lean-rich liquid heat exchanger 4; 5 is connected to the rich liquid circulation channel; the upper part of the high-pressure tower of the regeneration 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 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, 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 at the top of the regeneration high-pressure tower, and the gas outlet of the high-pressure reflux tank 12 is connected to the gas inlet at the top 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 regeneration 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 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; The heat supply 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 heat supply medium inlet of the reboiler 14, and the by-product steam obtained in the heat pump system 18 is circulated to the reboiler 14.

[0008] Preferably, the absorption tower 1 is an independent tower body. 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 lean liquid inlet at the upper part of the absorption tower 1, countercurrently contacts with the raw gas to absorb the acidic gas in the raw gas to generate amino salt compounds, the liquid collected by the liquid collector (i.e. lean amine liquid) is circulated to the absorption tower 1 through the outside of the tower, the liquid collected by the liquid collector overflows to the lower part of the lower absorption tower, further countercurrently contacts with the raw gas, and obtains rich amine liquid in the bottom of the absorption tower 1, and part of the rich amine liquid enters the heat pump system 18.

[0009] Preferably, a lean liquid circulation pump 19 is provided on the lean liquid circulation pipeline.

[0010] 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 channel 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.

[0011] 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, and 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.

[0012] As a specific embodiment of the desulfurization and decarbonization system described in the present invention, the heat pump system 18 includes an evaporator, a condenser, and a compressor. The rich liquid inlet (i.e., the heating medium inlet) of the evaporator is connected to the outlet of the rich liquid pump 2, and the rich liquid outlet (i.e., the heating medium outlet) of the evaporator 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. The rich amine liquid is cooled and then 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.

[0013] 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.

[0014] The intermediate medium is a refrigerant, and specifically, the refrigerant R-454B can be used.

[0015] A packing layer is provided at the upper part and the lower part 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 and CY, or plate corrugated packing such as 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y or structured packing with a large mass transfer area (CN207981192U), preferably 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y or structured packing with a large mass transfer area (CN207981192U).

[0016] 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.

[0017] The regeneration tower 6 is a tower body divided into two independent tower bodies.

[0018] 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.

[0019] Preferably, the rich liquid inlet of the regeneration low-pressure tower is at the tower plate layer; the air inlet of the regeneration low-pressure tower is at the tower plate layer; in the regeneration low-pressure tower, the rich liquid inlet is connected higher than the air inlet.

[0020] Preferably, the rich liquid inlet of the regeneration high-pressure tower is at the tower plate layer.

[0021] Preferably, the tower plate 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 wire mesh packing such as BX and 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).

[0022] Preferably, the tray in the regeneration high-pressure tower is a sieve plate, a float valve or a bubble cap. The filler in the regeneration high-pressure tower is a wire mesh filler such as BX, CY, or a plate corrugated filler such as 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y or a large mass transfer area structured filler (CN207981192U), preferably 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y or a large mass transfer area structured filler (CN207981192U).

[0023] 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 .

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Preferably, the liquid outlet of the regeneration low-pressure tower is provided with a low-pressure tower bottom pump 11, the outlet of the low-pressure tower bottom 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.

[0028] Preferably, a high-pressure reflux pump 13 is provided at the liquid outlet of the high-pressure reflux tank 12, 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.

[0029] 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.

[0030] 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, the outlet of the regeneration compressor 15 is connected to the steam inlet of the regeneration high-pressure tower, and 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.

[0031] 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 is in countercurrent contact with the raw gas, absorbs the acidic gas in the raw gas to generate amino salt compounds, and obtains rich amine liquid; the rich amine liquid enters a regeneration low-pressure tower and a regeneration high-pressure tower at the same time after being heated, and 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 gas in the raw gas.

[0032] Specifically, the steps include: 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; 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, and enters the low-pressure reflux tank 8 after being condensed by the low-pressure condenser 7. 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 being cooled. The cooled rich amine liquid is returned to the absorption tower 1; The rich amine liquid enters the high-pressure tower of the regeneration tower, and is heated by steam in the reboiler 14. The amino salt compounds are decomposed to obtain amine liquid and acidic gas. The regeneration gas containing acidic 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 is condensed, and the condensate and acidic gas enter the high-pressure reflux tank 12. The liquid is refluxed to the regeneration high-pressure tower. The non-condensable acidic gas is discharged from the high-pressure reflux tank to the low-pressure tower of the regeneration tower for stripping out the sulfur-containing and carbon-containing gases in the rich amine liquid; the lean amine liquid in the high-pressure tower kettle of the regeneration tower enters the low-pressure flash tank 16 through the pressure difference, and the lean amine liquid in the low-pressure flash tank is cooled by the high-temperature rich-lean liquid heat exchanger 4 and the lean liquid low-temperature cooler 3 in turn, and enters the absorption tower 1; the steam condensate discharged from the reboiler 14 enters the steam flash tank 20, and 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, and then recirculates to the reboiler 14.

[0033] 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 CO2 content in the raw gas is 5-30% mol, and the COS (carbonyl sulfide) content is 10-300 mg / Nm 3 , the content of H2S is 10~150mg / Nm 3 .

[0034] The amine liquid 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-triazine; the antioxidant is one of vanadium pentoxide, potassium chromate, and potassium metavanadate. The amine liquid of the present invention is an environmentally friendly absorbent with low corrosiveness and low scaling.

[0035] In the amine solution, the concentration of the absorbent is 15-60wt%, the concentration of the activator is 1-12wt%, the concentration of the enhancer is 0.2-1wt%, and the concentration of the antioxidant is 0.1-1 wt%.

[0036] 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.

[0037] 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.

[0038] The CO2 in the purified gas is ≤0.5% mol, and the total sulfur is ≤20mg / Nm 3 .

[0039] 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 the rich liquid outlet of the heat pump system 18 correspond to the temperatures of the rich amine liquid before and after heat exchange, respectively.

[0040] In step (2), the operating pressure of the regeneration low-pressure tower is 20-80 kPa, preferably 20-50 kPa; the operating temperature of the regeneration low-pressure tower is 104-120°C, preferably 104-115°C.

[0041] The operating temperature of the low-pressure condenser 7 is 30-50°C, preferably 32-42°C.

[0042] The non-condensable acidic gas in the low-pressure reflux tank is discharged outside the boundary for acid gas treatment.

[0043] 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.

[0044] The operating temperature of the lean liquid cryogenic cooler 3 is 20-50°C, preferably 25-43°C.

[0045] The operating pressure of the low-pressure flash tank 16 is -20 to 50 kPa, preferably 0 to 20 kPa.

[0046] The operating pressure of the steam flash tank 20 is -10 to 60 kPa, preferably 0 to 20 kPa.

[0047] 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.

[0048] 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 high-pressure tower of the regeneration 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 high-pressure tower of the regeneration tower.

[0049] The present invention has the following beneficial effects: The present invention combines the characteristics of desulfurization and decarbonization processes, adopts high-efficiency absorption amine liquid, and utilizes high-low pressure regeneration 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: 1. Conventional decarbonization and desulfurization systems mostly adopt a one-stage absorption and one-stage regeneration mode, and the system consumes a lot of regeneration energy; the amine liquid regeneration system of the present invention adopts high-low pressure thermal coupling technology, and divides the regeneration system into low-pressure regeneration and high-pressure regeneration, saving energy consumption.

[0050] 2. In conventional decarbonization and desulfurization regeneration systems, the regenerated rich and poor amine liquids at the bottom are not isolated, resulting in a short residence time of the amine liquid and a poor regeneration effect when the liquid level is too low. The present invention collects the rich amine liquid of 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 from the reboiler, effectively separating the rich amine liquid from the lean amine liquid, thereby ensuring the regeneration time and regeneration effect of the amine liquid.

[0051] 3. Conventional decarbonization and desulfurization regeneration systems release heat during the decarbonization and desulfurization reaction process, resulting in an outlet gas temperature higher than the inlet temperature, water in the amine liquid being lost to the outlet gas phase, and the amine liquid concentration continuously increasing; the present invention directly passes the steam flashed out of the steam condensate into the regeneration high-pressure tower kettle after compression, directly heats the amine liquid, replenishes the lost water in the system, reduces the acid gas partial pressure, is easy to regenerate, increases the water content of the compressed gas, increases the enthalpy value, increases the COP (refrigeration efficiency) of the compressor, and saves more electricity. Recycling flash steam and reducing the addition of high-quality steam can save more than 10% of energy, increase the water content in the regeneration high-pressure tower kettle, and reduce the concentration of amine liquid, which is more conducive to the regeneration of amine liquid, and the amine liquid is not easy to deteriorate.

[0052] 4. The present invention performs low-flash evaporation on the high-pressure lean amine liquid, and the acid gas after flash evaporation is compressed and returned to the regeneration high-pressure tower, which can not only further remove the acid gas dissolved in the amine liquid, but also the acid gas after compression has a high temperature and enters the regeneration high-pressure tower to heat the amine liquid, thereby saving steam energy by more than 11%.

[0053] 5. The present invention utilizes heat pump technology to convert the by-product steam generated by the reaction heat in the absorption tower into regeneration of the amine liquid, thereby reducing the consumption of steam and circulating water, and the steam consumption can be saved by more than 50%.

[0054] 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 reduce the investment cost.

[0055] Table 1. Effect of amine liquid temperature on acid gas load and circulation rate

[0056] 7. The present invention introduces the high-temperature regeneration gas of the regeneration high-pressure tower into the regeneration low-pressure tower, breaking through the thermal pinch point temperature, making heat utilization more reasonable, and stripping out the sulfur-containing and carbon-containing gases in the amine liquid without the problem of repeated acid gas pollution, recovering the heat in the exhaust gas, and reducing steam consumption.

[0057] 8. The absorption tower adopts two-stage amine liquid circulation. The bottom temperature is high, the reaction is violent 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.

[0058] 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

[0059] Figure 1 It is a schematic diagram of the process of the present invention for desulfurization and decarbonization process.

[0060] Figure 1In 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-thermally coupled 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

[0061] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Example 1

[0062] like Figure 1 As shown, a desulfurization and decarbonization system includes: a flue gas absorption system and an amine liquid regeneration system.

[0063] The flue gas regeneration system comprises 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, 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 part 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 body collector and the lower packing layer; 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 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 channel 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, countercurrently contacts with the raw gas to absorb the acidic gas in the raw gas to generate 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, further countercurrently contacts with the raw gas, and rich amine liquid is obtained in the kettle of the absorption tower 1, and part of the rich amine liquid enters the heat pump system 18, the heat pump system 18 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 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 rich amine liquid exchanges heat with the refrigerant R-454B in the evaporator of the heat pump system. The heat in the rich amine liquid is transferred to the refrigerant by evaporating the refrigerant. The rich amine liquid is cooled and then circulated 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. By exchanging heat with the steam condensate, the heat in the refrigerant is transferred to the steam condensate in the steam flash tank 20 to produce steam. ;

[0064] The amine liquid regeneration system comprises 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 cryogenic 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 is a regeneration low-pressure tower, and the lower section is a regeneration high-pressure tower; the upper part of the regeneration low-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 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; A rich liquid inlet is provided on the corresponding plate layer side of the regeneration low-pressure tower. The rich liquid inlet is on the plate. 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. A thermal coupling reboiler 10 is provided at the lower part of the regeneration low-pressure tower. All the liquids collected by the liquid collector inside the regeneration low-pressure tower enter the thermal coupling reboiler 10, and enter the regeneration low-pressure tower after being heated by the thermal coupling reboiler 10. The top gas 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 gas 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 bottom liquid outlet 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 heat is 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, and 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, and the regeneration tower 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, and the by-product steam obtained in the heat pump system 18 is circulated to the reboiler 14.

[0065] The gas outlet at the top of the regeneration high-pressure tower is connected to the heat 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 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 at 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 at 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 regeneration 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 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

[0066] The desulfurization and decarbonization system according to Example 1 desulfurizes and decarbonizes the sulfur- and carbon-containing raw gas, comprising the following steps: Step (1): Raw gas from the off-site pipeline (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 filler, pressure: 15kPa) from the lower air inlet, amine liquid (amine liquid is 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℃) is introduced into absorption tower 1 from the upper lean liquid inlet, and the gas-liquid ratio of the top circulation volume of the absorption tower is controlled to be 800, and the gas-liquid ratio of the bottom circulation volume is 180. In absorption tower 1, the raw gas contacts with the amine liquid in countercurrent, and the acidic gas in the raw gas is absorbed by the amine liquid to generate amino salt compounds, and the purified gas (temperature: 50℃, CO2 content: 0.3% mol, total sulfur content: 12 mg / Nm 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 further contacts with the feed gas in countercurrent, and obtains 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 a rich liquid pump 2, and a part of the rich amine liquid enters the heat pump system 17. 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; another 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 which the rich amine liquid exchanges heat with the lean amine liquid regenerated from the regeneration low-pressure tower and is heated to 85°C, and 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, and the rich amine liquid after heat exchange simultaneously enters the regeneration low-pressure tower and the regeneration high-pressure tower of the regeneration tower 6; Step (2): The rich amine liquid enters the low-pressure tower of the regeneration tower (filler: 250Y corrugated packing, tower plate: floating valve tower plate, temperature: 107°C, pressure: 21 kPa), countercurrently contacts with the non-condensable acidic gas from the high-pressure reflux tank 12, and then passes through the thermal coupling reboiler 10 (K-type kettle reboiler) for heating, and the amino salt compound is decomposed to obtain amine liquid and acidic gas. The regenerated acidic gas enters the low-pressure condenser 7 (temperature: 35°C, pressure: 21kPa) condensation, condensate and acid gas enter low-pressure reflux tank 8, condensate is refluxed back into the tower through low-pressure reflux pump 9, non-condensable acid gas is discharged from low-pressure reflux tank 8 to the outside for acid gas treatment; the lean amine liquid (acid gas load mol / mol amine: 4) in the low-pressure kettle of the regeneration tower is pumped into the low-temperature lean-rich liquid heat exchanger 5 by the low-pressure kettle pump 11 for heat exchange with the rich amine liquid from the adsorption tower 1, and then merged with the rich amine liquid from the absorption tower 1 to enter the heat pump system 18; The rich amine liquid enters the high-pressure tower of the regeneration tower (filler: 250Y corrugated packing, tower plate: floating valve tower plate, temperature: 127°C, pressure: 120kPa), and is heated by steam in the reboiler 14 (K-type kettle reboiler). The amino salt compound is decomposed to obtain amine liquid and acid gas. The regenerated acid gas enters the thermal coupling reboiler 10 (temperature: 125°C, pressure: 120kPa) from the top of the tower as a heating heat source for the low-pressure tower of the regeneration tower. The regenerated acid gas is condensed to obtain 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 low-pressure tower of the regeneration tower from the air inlet of the regeneration low-pressure tower. The non-condensable acid gas is countercurrently contacted with the rich amine liquid entering the regeneration low-pressure tower to strip out the sulfur-containing and carbon-containing gases in the rich amine liquid. The lean amine liquid in the high-pressure kettle of the regeneration tower enters the low-pressure flash tank 16 (pressure: 0 kPa), and the acid gas after flashing is compressed back into the high-pressure kettle of the regeneration tower by the regeneration compressor 15. 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: 32°C) by the high-pressure kettle pump 17 in sequence to exchange heat with the rich amine liquid and circulating water respectively, and is cooled to 32°C, and then enters the absorption tower 1 from the lean liquid inlet; The steam condensate from the reboiler 14 enters the steam flash tank 20 (temperature: 100°C, pressure: 0 kPa), and the flash gas is compressed by the regeneration compressor 15 and returned to the high-pressure kettle of the regeneration tower. 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 and high-pressure gas formed by the refrigerant compressed by the compressor, and low-pressure steam (temperature: 140°C) is produced as a by-product, and the steam is circulated to the reboiler 14. Example 3

[0067] The desulfurization and decarbonization system according to Example 1 desulfurizes and decarbonizes the sulfur- and carbon-containing raw gas, comprising the following steps: Step (1): Raw gas from the off-site pipeline (temperature: 42°C, pressure: 15 kPa, CO2 content: 22% mol, COS content: 150 mg / Nm 3 , H2S content: 40mg / Nm 3) enters the absorption tower 1 (filler: 125Y corrugated filler, pressure: 10kPa) from the lower air inlet, and the amine liquid (amine liquid is 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℃) is introduced into the absorption tower from the upper lean liquid inlet, and the gas-liquid ratio of the top circulation volume of the absorption tower is controlled to be 800, and the gas-liquid ratio of the bottom circulation volume is 150. In the absorption tower 1, the raw gas is countercurrently contacted with the amine liquid, and the acidic gas in the raw gas is absorbed by the amine liquid to generate amino salt compounds, and the purified gas (temperature: 58℃, CO2 content: 0.5% mol, total sulfur content: 18 mg / Nm 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 through a lean liquid circulation pipeline; 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, and obtains 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 a rich liquid pump 2, and a part of the rich amine liquid enters the heat pump system 17. 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 system 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; another 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 simultaneously enters the regeneration low-pressure tower and the regeneration high-pressure tower of the regeneration tower 6; Step (2): the rich amine liquid enters the low-pressure tower of the regeneration tower (filler: 250Y corrugated packing, tower plate: floating valve tower plate, temperature: 110°C, pressure: 25 kPa), countercurrently contacts with the non-condensable acidic gas from the high-pressure reflux tank 12, and then is heated by the thermally coupled reboiler 10 (K-type kettle reboiler), the amino salt compound is decomposed to obtain amine liquid and acidic gas, the regenerated acidic gas enters the low-pressure condenser 7 (temperature: 38°C, pressure: 25 kPa) from the top of the tower for condensation, the condensate and the acidic gas enter the low-pressure reflux tank 8, the condensate is refluxed back into the tower through the low-pressure reflux pump 9, and the non-condensable acidic gas is discharged from the low-pressure reflux tank 8 to the outside for acidic gas treatment; the lean amine liquid (acid gas load mol / mol amine: 4) in the low-pressure tower kettle of the regeneration tower is pumped into the low-temperature lean-rich liquid heat exchanger 5 by the low-pressure tower kettle pump 11, and merges with the rich amine liquid from the absorption tower 1 to enter the heat pump system 18; The rich amine liquid enters the high-pressure tower of the regeneration tower (filler: 250Y corrugated packing, tower plate: floating valve tower plate, temperature: 130°C, pressure: 125kPa), and is heated by steam in the reboiler 14 (K-type kettle reboiler). The amino salt compound is decomposed to obtain amine liquid and acid gas. The regenerated acid gas enters the thermal coupling reboiler 10 (temperature: 128°C, pressure: 125kPa) from the top of the tower as a heating heat source for the low-pressure tower of the regeneration tower. The regenerated acid gas is condensed to obtain 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 low-pressure tower of the regeneration tower from the air inlet of the regeneration low-pressure tower. The non-condensable acid gas countercurrently contacts with the rich amine liquid entering the regeneration low-pressure tower to strip out the sulfur-containing and carbon-containing gases in the rich amine liquid. The lean amine liquid in the high-pressure kettle of the regeneration tower enters the low-pressure flash tank 16 (pressure: 5 kPa), and the acid gas after flashing is compressed by the regeneration compressor 15 and then returns to the high-pressure kettle of the regeneration tower. 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 kettle pump 17 in sequence to exchange heat with the rich amine liquid and circulating water respectively, and is cooled to 40°C, and then enters the absorption tower 1 from the lean liquid inlet; The steam condensate from the reboiler 14 enters the steam flash tank 20 (temperature: 101°C, pressure: 5 kPa), and the flash gas is compressed by the regeneration compressor 15 and returned to the high-pressure kettle of the regeneration tower. 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 and high-pressure gas formed by the compression of the refrigerant by the compressor. The by-product low-pressure steam (temperature: 140°C) is circulated to the reboiler 14. Example 4

[0068] The desulfurization and decarbonization system according to Example 1 desulfurizes and decarbonizes the sulfur- and carbon-containing raw gas, comprising the following steps: Step (1): Raw gas from the off-site pipeline (temperature: 53°C, pressure: 6 kPa, CO2 content: 22% mol, COS content: 150 mg / Nm 3 , H2S content: 40mg / Nm 3 ) enters the absorption tower 1 (filler: 125Y corrugated filler, pressure: 6kPa) from the lower air inlet, and the amine liquid (amine liquid is a mixed aqueous solution of N-methyldiethanolamine, methylethanolamine, 2,5-hydroxypiperazine and vanadium pentoxide, N-methyldiethanolamine: 38wt%, methylethanolamine 2wt%, 2,5-hydroxypiperazine 0.5wt%, vanadium pentoxide 0.2wt%; temperature: 43°C) is introduced into the absorption tower from the upper lean liquid inlet, and the gas-liquid ratio of the top circulation volume of the absorption tower is controlled to be 800, and the gas-liquid ratio of the bottom circulation volume is 110. In the absorption tower 1, the raw gas is countercurrently contacted with the amine liquid, and the acidic gas in the raw gas is absorbed by the amine liquid to generate amino salt compounds, and the purified gas (temperature: 59°C, CO2 content: 0.5% mol, total sulfur content: 20 mg / Nm 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 further contacts with the feed gas in countercurrent, and obtains 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 a rich liquid pump 2, and a part of the rich amine liquid enters the heat pump system 17. 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; another 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 which the rich amine liquid exchanges heat with the lean amine liquid regenerated from the regeneration low-pressure tower and is heated to 85°C, in which 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, and 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; Step (2): the rich amine liquid enters the low-pressure tower of the regeneration tower (filler: 250Y corrugated packing, tower plate: floating valve tower plate, temperature: 104°C, pressure: 20 kPa), countercurrently contacts with the non-condensable acidic gas from the high-pressure reflux tank 12, and then is heated by the thermally coupled reboiler 10 (K-type kettle reboiler), the amino salt compound is decomposed to obtain amine liquid and acidic gas, the regenerated acidic gas enters the low-pressure condenser 7 (temperature: 40°C, pressure: 20 kPa) from the top of the tower for condensation, the condensate and the acidic 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 acidic gas is discharged from the low-pressure reflux tank 8 to the outside for acidic gas treatment; the lean amine liquid (acid gas load mol / mol amine: 3) in the kettle of the low-pressure tower of the regeneration tower is pumped into the low-temperature lean-rich liquid heat exchanger 5 by the low-pressure tower kettle pump 11, and merges with the rich amine liquid from the absorption tower 1 to enter the heat pump system 18; The rich amine liquid enters the regeneration high-pressure tower (filler: 250Y corrugated packing, tower plate: floating valve tower plate, temperature: 124°C, pressure: 120kPa), and is heated by steam in the reboiler 14 (K-type kettle reboiler). The amino salt compound is decomposed to obtain 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 heat source for the regeneration low-pressure tower. The regenerated acid gas is condensed to obtain 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 with the rich amine liquid entering the regeneration low-pressure tower to strip out the sulfur-containing and carbon-containing gases in the rich amine liquid. The lean amine liquid in the high-pressure kettle of the regeneration tower enters the low-pressure flash tank 16 (pressure: 20 kPa), and the acid gas after flashing is compressed by the regeneration compressor 15 and then returns to the high-pressure kettle of the regeneration tower. 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 kettle pump 17 in sequence to exchange heat with the rich amine liquid and circulating water respectively, and is cooled to 43°C, and then enters the absorption tower 1 from the lean liquid inlet; 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 high-pressure kettle of the regeneration tower. 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 produce low-pressure steam (temperature: 140°C) as a by-product, which exchanges heat with the high-temperature, high-pressure gas compressed by the compressor and circulates to the reboiler 14. Example 5

[0069] 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 .

[0070] The original process of the 400,000-ton CCUS unit adopted a single-stage absorption tower plus a single-stage regeneration tower system.

[0071] The energy consumption of the decarbonization and desulfurization device of the original process and the process of the present invention (taking Example 2 as an example) is shown in Table 2.

[0072] Table 2. Comparison of energy consumption of decarbonization and desulfurization devices between the original process and the process of the present invention

Claims

1. A desulfurization and decarbonization system, characterized in that: include: Flue gas absorption system, amine liquid regeneration system; The flue gas regeneration system comprises 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, and the air inlet is connected to the raw gas pipeline to pass the raw gas into 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, and the liquid at the upper part of the absorption tower overflows from the liquid collector into the lower part, and the lower gas enters through the liquid collector The upper part is provided with a rich liquid circulation inlet in the middle below the liquid collector; the middle part of the absorption tower is provided with a lean liquid outlet, which is connected to the lean liquid inlet through a lean liquid circulation pipeline, and the liquid collected by the liquid collector is circulated to the absorption tower through the lean liquid circulation pipeline outside the tower; the rich liquid outlet at the bottom of the absorption tower 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 through a low-temperature lean-rich liquid heat exchanger and a high-temperature lean-rich liquid heat exchanger in turn, and the rich liquid circulation channel is connected to the rich liquid circulation inlet through a heat pump system; The amine liquid regeneration system comprises 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 comprises an upper regeneration low-pressure tower and a lower regeneration high-pressure tower; the upper part of the regeneration low-pressure tower is a plate 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 gas outlet on the top of the regeneration low-pressure tower is connected to the low-pressure condenser and the low-pressure reflux tank in turn, and the liquid outlet of the low-pressure reflux tank is connected to the reflux port on the top of the regeneration low-pressure tower; the liquid outlet at the bottom of the regeneration low-pressure tower is connected to the rich liquid circulation tank via the low-temperature lean-rich liquid heat exchanger. The regeneration tower is connected to a loop; the upper part of the high-pressure tower of the regeneration tower is a plate layer, and the lower part is a packing layer, and a liquid collector is arranged below the packing layer; the rich liquid inlet of 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, and the gas outlet of the top 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 top of the regeneration high-pressure tower, and the gas outlet of the high-pressure reflux tank is connected to the gas inlet on the top 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 heat supply 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 heat supply 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 part and the lower part of the absorption tower respectively; the packing used in the absorption tower is a structured packing, which 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 or a large mass transfer area structured packing disclosed in CN207981192U; The tower plate 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, CY wire mesh packing, or a 125X, 125Y, 250X, 250Y, 350X, 350Y, 450X, 450Y, 500X, 500Y, 700X, 700Y, 750X, 750Y plate corrugated packing or a large mass transfer area structured packing disclosed in CN207981192U; 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 or large mass transfer area structured fillers disclosed in CN207981192U.

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 at the top 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 at the top of the regeneration high-pressure tower; The liquid outlet of the low-pressure flash tank is provided with a high-pressure tower bottom pump, the outlet of the high-pressure tower bottom 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 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 through the lean liquid circulation pipeline outside the tower. Rich amine liquid is obtained in the kettle of the absorption tower. 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 the acid gas is discharged from the top of the regeneration low-pressure tower, condensed by a low-pressure condenser, and enters a 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 returns to the absorption tower; The rich amine liquid enters the high-pressure tower of the regeneration tower, and is heated by steam in the reboiler. The amino salt compounds are decomposed to obtain 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 refluxes 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 for stripping out the sulfur-containing and carbon-containing gases in the rich amine liquid; the lean amine liquid in the kettle of the high-pressure tower of the regeneration tower enters the low-pressure flash tank through the pressure difference, and the lean amine liquid in the low-pressure flash tank is cooled by the high-temperature rich-lean liquid heat exchanger and the lean liquid low-temperature cooler in turn, and enters the absorption tower; the steam condensate discharged from the reboiler enters the steam flash tank, and part of the condensate in the steam flash tank is discharged outside the boundary, and part enters the heat pump system to produce steam, which is recycled to the reboiler.

7. The method for desulfurization and decarbonization 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 cryocooler 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 method for desulfurization and decarbonization according to claim 6 or 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 cryocooler 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 method for desulfurization and decarbonization 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 high-pressure tower of the regeneration tower; the flash gas obtained after flash evaporation in the steam flash tank is compressed by the regeneration compressor and then enters the high-pressure tower of the regeneration tower.

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