Energy-saving system and method for hydrogen-rich carbon cycle oxygen blast furnace sintering low-grade waste heat coupled decarburization amine liquid regeneration

Abstract

This invention belongs to the field of waste heat utilization technology, specifically disclosing an energy-saving system for the regeneration of decarbonized amine liquid coupled with low-grade waste heat from sintering in a hydrogen-rich carbon-circulating oxygen blast furnace. The system includes an absorption tower, connected to a purified gas separator and a regeneration tower. A lean liquor cooler and a lean liquor pump are connected in series on the pipeline connecting the absorption tower and the regeneration tower. A heat exchanger is connected to the absorption tower, connected to a hot water pipe from the sintering ring cooler and a flash tank. The flash tank is connected to the regeneration tower, which is also connected to a reboiler. A regeneration gas cooler and a regeneration gas separator are connected in series on the regeneration tower. Addressing the problem of high steam consumption in existing hydrogen-rich carbon-circulating oxygen blast furnace decarbonization devices, this invention recovers low-grade waste heat (85-90℃) from the sintering ring cooler, replacing high-quality steam with waste heat. This solves the problem of high steam consumption and insufficient utilization of low-grade waste heat from the sintering ring cooler in existing hydrogen-rich carbon-circulating oxygen blast furnace decarbonization devices, resulting in energy waste.

Description

Technical Field

[0001] This invention relates to the field of waste heat utilization technology, specifically to an energy-saving system and method for regenerating low-grade waste heat from hydrogen-rich carbon-circulating oxygen blast furnace sintering coupled with decarbonized amine liquid. Background Technology

[0002] The steel industry, with its long-process smelting, has high total carbon emissions and faces enormous pressure to reduce them. Carbon capture, utilization, and storage (CCUS) technology is an indispensable core technology for achieving deep decarbonization in the industry. Among these technologies, amine-based carbon dioxide capture is mature and has stable capture efficiency, and it has been gradually implemented in industrial demonstration applications in steel projects.

[0003] Traditional amine liquor regeneration processes require high-quality steam at 110℃ and 0.3-0.4MPa for heating. Steam energy consumption accounts for a very high proportion of the total energy consumption of the decarbonization unit, significantly increasing the operating cost of the decarbonization system and becoming a key bottleneck restricting the large-scale promotion of CCUS technology for hydrogen-rich carbon-cycle oxygen blast furnaces. Meanwhile, the sintering process associated with the blast furnace has a large amount of idle low-grade waste heat resources: the sintering ring cooler can continuously produce 85-90℃ closed-loop hot water during the cooling of sintered ore, with the total waste heat capacity of the entire production line reaching 57GW, perfectly matching the heat demand for 77℃ amine liquor regeneration. However, current industry efforts to recover and utilize sintering waste heat only focus on producing medium- and high-pressure steam from high-temperature flue gas. The 85-90℃ low-temperature hot water, lacking suitable downstream heat users, is mostly directly sent to cooling towers for cooling and venting, resulting in a waste heat utilization rate of less than 30%. A large amount of low-grade heat energy is wasted, highlighting the problem of energy waste.

[0004] Current research on low-grade industrial waste heat coupled with amine liquor regeneration mainly focuses on waste heat from power plant low-temperature flue gas and steel plant slag flushing water. Energy-saving solutions for low-temperature waste heat coupled with decarburized amine liquor regeneration in sintering ring coolers are not yet mature, and existing technologies still have the following shortcomings: 1. The heat exchange point setting is unreasonable, with the CO2 pre-desorption rate reaching up to 27000 Nm³ during the rich liquor low-pressure heating stage. 3 The system suffers from several drawbacks: First, the gas-liquid two-phase operation significantly increases the heat exchanger volume and equipment investment. Second, the heat exchange equipment lacks sufficient corrosion resistance, anti-clogging, and anti-cavitation performance. Impurities in the amine solution and corrosive media can easily cause equipment leaks and frequent shutdowns, making it difficult to meet the long-cycle production requirements of steelmaking. Third, the flow and temperature control logic is too simple to adapt to the precise temperature control requirements of 77℃±2℃ in the semi-lean-rich liquor process, and waste heat fluctuations directly interfere with the stability of the main decarbonization system. Fourth, the system lacks a multi-parameter linkage intelligent control system for temperature, pressure, differential pressure, and CO2 desorption, and there are no self-stabilizing mechanisms such as automatic flushing and pressure fine-tuning, resulting in a low system utilization rate.

[0005] In summary, to solve the above problems, it is necessary to design an energy-saving system and method for regenerating decarbonized amine liquid coupled with the low-grade waste heat of sintering in a hydrogen-rich carbon-circulating oxygen blast furnace. This would address the issues of high steam consumption in the decarbonization device of the hydrogen-rich carbon-circulating oxygen blast furnace under existing technology, as well as the underutilization of the low-grade waste heat of the sintering ring cooler, resulting in energy waste. Summary of the Invention

[0006] The purpose of this invention is to provide an energy-saving system and method for regenerating low-grade waste heat from sintering in a hydrogen-rich carbon-circulating oxygen blast furnace coupled with decarbonization amine liquid, in order to solve the problem of high steam consumption in the existing decarbonization device of the hydrogen-rich carbon-circulating oxygen blast furnace and the failure to fully utilize the low-grade waste heat of the sintering ring cooler, resulting in energy waste.

[0007] To achieve the above objectives, the basic solution provided by this invention is as follows: an energy-saving system for regenerating low-grade waste heat coupled with decarbonized amine liquid in a hydrogen-rich carbon-circulating oxygen blast furnace sintering process, comprising an absorption tower, wherein the gas outlet of the absorption tower is connected to a purified gas separator, the liquid inlet of the absorption tower is connected to a regeneration tower, a lean liquid cooler and a first lean liquid pump are connected in series on the pipeline connecting the absorption tower and the regeneration tower, a plate heat exchanger is connected to the liquid outlet of the absorption tower, a hot water pipe of a sintering ring cooler and a flash tank are connected to the plate heat exchanger, the liquid phase outlet at the bottom of the flash tank is connected to the regeneration tower, a reboiler is connected to the regeneration tower, a condensate separator is provided at the heat source outlet of the reboiler, a regeneration gas cooler and a regeneration gas separator are connected in series at the gas phase outlet at the top of the regeneration tower, the liquid phase outlet of the regeneration gas separator is connected to the regeneration tower, and a reflux pump is provided on the pipeline connecting the regeneration gas separator and the regeneration tower.

[0008] The beneficial effects of the present invention are as follows: (1) The present invention uses the waste circulating hot water of the sintering ring cooler at 85-90℃ as a heat source, and is equipped with a polyurethane insulated distribution pipeline network to control the heat loss of the pipeline to within 3%, and is equipped with a 3000m 3 The / h variable frequency closed soft water pump station stably delivers waste heat, which can stably replace more than 40 tons of high-quality steam per hour in the decarbonization unit. The waste heat utilization rate has increased from less than 30% to more than 85%, which greatly reduces the fuel cost of the decarbonization system and reduces the fossil energy consumption caused by steam production. It lowers the operating threshold of steel CCUS projects from the source and solves the industrialization pain points of high energy consumption and poor economic efficiency of traditional amine decarbonization process. (2) In this invention, a plate heat exchanger is installed in the high-pressure rich liquid section (≥1.6MPa) before the pressure reducing valve of the absorption tower. The synergistic effect of high-pressure operation combined with low-temperature heat exchange at 77℃ fundamentally suppresses premature CO2 precipitation during the rich liquid heating process. In traditional processes, the CO2 pre-desorption capacity during the heating stage is as high as 27000 Nm³. 3 / h, the present invention can control the pre-desorption capacity at 3000 Nm 3Within a certain range, the desorption inhibition rate exceeds 88.9%, and the heat exchanger equipment volume is reduced by more than 80% compared with the traditional solution, significantly reducing equipment procurement and civil engineering investment; at the same time, it is equipped with a customized plate heat exchanger, and the pressure drop on the amine liquid side is stable at ≤28kPa, reducing the power loss of the rich liquid transfer pump; when the temperature is abnormal, the hot water flow rate is adjusted, and when the pre-desorption amount exceeds the standard, the amine liquid pressure is finely adjusted to 1.7MPa, and the operating conditions are stably controlled throughout the process, avoiding the increase of compressor and flash tank processing load by a large amount of pre-desorption gas; (3) The heat exchange core of this invention uses a fully welded plate heat exchanger, combined with an online side-filter device for amine liquid to intercept rust, dust and corrosion deposits in advance, which solves the problems of heat exchanger blockage, leakage and cavitation under corrosive amine liquid conditions. The core heat exchange equipment can run continuously and stably for more than 8,000 hours. The process operation does not affect the decarbonization and purification effect of blast furnace gas. On the basis of stable production of qualified circulating metallurgical gas and high-purity CO2 product gas, carbon emissions can be reduced by more than 105,000 tons per year, achieving zero waste of sintering waste heat, and has both industrial practical value and significant environmental benefits.

[0009] Option 2, a preferred embodiment of the basic option, involves an amine side-stream filter connected to the regeneration tower, with a second lean solution pump installed on the pipeline connecting the regeneration tower and the amine side-stream filter. The amine side-stream filter can filter rust, corrosion precipitates, and dust impurities from the amine solution, preventing blockage of the plate heat exchanger and the lean / rich solution heat exchanger channels; thereby reducing impurities entering the regeneration tower, lowering the amine degradation rate, and extending the solvent replacement cycle.

[0010] Option 3, a preferred option of the basic scheme, includes a purified gas expander installed on the pipeline connecting the absorption tower and the purified gas separator, and an amine liquid hydraulic turbine installed on the pipeline connecting the absorption tower and the plate heat exchanger. The purified gas expander can recover the residual pressure of the high-pressure blast furnace gas after decarbonization and convert it into electrical energy to reduce the power consumption of system pumps; the amine liquid hydraulic turbine can recover the pressure energy of the high-pressure rich liquid at the bottom of the absorption tower, reducing the energy consumption of the rich liquid transfer pump; thus further reducing the overall power consumption of the decarbonization unit.

[0011] Option 4, a preferred option of the basic scheme, features a polyurethane insulation layer on the hot water pipe of the sintered ring cooler, with an outer protective pipe surrounding the polyurethane insulation layer. This significantly reduces heat loss from the hot water pipes, ensuring that the 85-90℃ hot water reaches the plate heat exchanger at the correct temperature; it also reduces waste heat and stabilizes the rich liquid heat exchange within the range of 77℃±2℃.

[0012] Option 5, an energy-saving method for regenerating low-grade waste heat from hydrogen-rich carbon-circulating oxygen blast furnace sintering coupled with decarbonized amine liquid, characterized by comprising the following steps: S1: CO2 capture: First, the blast furnace gas is sent to the bottom of the absorption tower, so that the blast furnace gas passes through the packing layer inside the tower from bottom to top. At this time, the lean liquid in the regeneration tower is cooled by the first lean liquid pump and then transported to the top of the absorption tower and sprayed from top to bottom. At the same time, it comes into countercurrent contact with the rising blast furnace gas. At this time, the lean liquid selectively absorbs CO2 in the blast furnace gas to generate rich liquid. S2: Coupled heat exchange: First, the high-pressure rich liquid at the bottom of the absorption tower is recovered by the amine liquid hydraulic turbine. Then, the rich liquid is sent to the plate heat exchanger. The rich liquid is indirectly heated by the circulating hot water of the sintering ring cooler. After the heat exchange and temperature rise, the rich liquid enters the flash tank for flash evaporation and releases gas containing H2 and CO. The released flash vapor flows from the top of the flash tank into the gas compressor inlet manifold. S3: Amine Regeneration: First, the rich liquid at the bottom of the flash tank is sent to the regeneration tower, where it is regenerated in the upper part of the tower. The regenerated lean liquid is collected at the bottom of the tower. Then, the lean liquid at the bottom of the tower is pumped into the amine side filter to filter impurities and corrosion products. After that, it enters the reboiler from the bottom of the tower. Steam is introduced to heat the lean liquid, causing some of the amine liquid to vaporize and form a gas-liquid mixture. The gas-liquid mixture is then returned from the reboiler to the lower section of the tower to provide the high-temperature steam required for desorption.

[0013] Waste heat can be utilized to reduce steam consumption at the source and lower the operating costs of carbon capture.

[0014] Option 6, a preferred option of Option 5, involves the purified gas (after CO2 removal) exiting from the top of the absorption tower in S1. The purified gas then passes through a purified gas expander to recover residual pressure. Next, a purified gas separator collects free moisture and condensate from the purified gas. Finally, the purified gas is cooled and fed into the blast furnace as circulating metallurgical gas. Simultaneous recovery of residual gas pressure enables power generation, achieving multi-stage energy recovery. The separator removes amine droplets entrained in the gas, preventing amine loss with the circulating gas and reducing reagent consumption.

[0015] Option 7, a preferred option of Option 5, in S2, the circulating hot water temperature of the sintering ring cooler is 85-90℃, the rich liquid temperature before heat exchange is 45℃, the rich liquid temperature after heat exchange is 77±2℃, and the rich liquid flow rate is 3400 m³ / h. 3 / h.

[0016] Option 8, a preferred option of Option 5, involves adjusting the circulating hot water flow rate of the sintering ring cooler to 3200 m³ / h in S2 if the amine liquid heat exchange temperature is <75℃. 3 / h; When the amine liquid heat exchange temperature is >79℃, the circulating hot water flow rate of the sintering ring cooler is adjusted to 2800m³ / h. 3 / h, the rich liquid pressure is adjusted to 1.7MPa.

[0017] Option 9, a preferred option of Option 5, involves the CO2-rich desorbed gas generated during rich liquid regeneration in S3. After being cooled by a regeneration gas cooler, the gas enters a regeneration gas separator for liquid separation. The separated gas is sent to the venting system, while the condensed amine liquid and condensate are returned to the regeneration tower via a reflux pump. The CO2 desorption rate is ≤3000 Nm³. 3 / h. All condensed amine liquid is recycled back to the regeneration tower, significantly reducing the amount of amine liquid replenished and saving reagent costs. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an energy-saving system for regenerating low-grade waste heat coupled with decarbonized amine liquid in a hydrogen-rich carbon-circulating oxygen blast furnace sintering process, according to the present invention.

[0019] The reference numerals in the accompanying drawings of the instruction manual include: 1. Absorption tower; 2. Purified gas separator; 3. Regeneration tower; 4. Lean liquid cooler; 5. First lean liquid pump; 6. Plate heat exchanger; 7. Hot water pipe of sintering ring cooler; 8. Flash tank; 9. Reboiler; 10. Condensate separator; 11. Regeneration gas cooler; 12. Regeneration gas separator; 13. Reflux pump; 14. Amine liquid bypass filter; 15. Second lean liquid pump; 16. Purified gas expander; 17. Amine liquid hydraulic turbine. Detailed Implementation

[0020] The present invention will be further described in detail below through specific embodiments: Example like Figure 1 As shown, an energy-saving system for regenerating low-grade waste heat from blast furnace sintering coupled with decarbonization amine liquor in a hydrogen-rich carbon-cycled oxygen blast furnace includes an absorption tower 1. A purified gas expander 16 and a purified gas separator 2 are connected in series at the outlet of the absorption tower 1. A regeneration tower 3 is connected to the inlet of the absorption tower 1. A lean liquor cooler 4 and a first lean liquor pump 5 are connected in series on the pipeline connecting the absorption tower 1 and the regeneration tower 3. An amine liquor hydraulic turbine 17 and a plate heat exchanger 6 are connected in series at the outlet of the absorption tower 1. A sintering ring cooler hot water pipe 7 and a flash tank 8 are connected to the plate heat exchanger 6. A polyurethane coating is installed on the sintering ring cooler hot water pipe 7. The insulation layer is a polyurethane insulation layer with an outer protective pipe. The liquid phase outlet at the bottom of the flash tank 8 is connected to the regeneration tower 3. The regeneration tower 3 is connected to a reboiler 9 and an amine liquid side filter 14. The heat source outlet of the reboiler 9 is equipped with a condensate separator 10. A second lean liquid pump 15 is installed on the pipeline connecting the regeneration tower 3 and the amine liquid side filter 14. The gas phase outlet at the top of the regeneration tower 3 is connected in series with a regeneration gas cooler 11 and a regeneration gas separator 12. The liquid phase outlet of the regeneration gas separator 13 is connected to the regeneration tower 3. A reflux pump 13 is installed on the pipeline connecting the regeneration gas separator 12 and the regeneration tower 3.

[0021] Based on the above-mentioned energy-saving system of low-grade waste heat coupled with decarbonized amine liquor regeneration in a hydrogen-rich carbon-circulating oxygen blast furnace, an energy-saving method for regenerating low-grade waste heat coupled with decarbonized amine liquor in a hydrogen-rich carbon-circulating oxygen blast furnace is provided, specifically including the following steps: S1: CO2 capture: First, blast furnace gas is fed into the bottom of absorption tower 1, allowing it to pass through the packing layer inside the tower from bottom to top. At this time, the lean liquid that has been regenerated in regeneration tower 3 is cooled by the first lean liquid pump 5 and then transported to the top of absorption tower 1 and sprayed from top to bottom. At the same time, it comes into countercurrent contact with the rising blast furnace gas. At this time, the lean liquid selectively absorbs CO2 from the blast furnace gas to generate rich liquid. The purified gas after CO2 removal is discharged from the top of absorption tower 1, and then passes through the purified gas expander 16 to recover the residual pressure of the purified gas. After passing through the purified gas separator 2, the free water and condensate in the purified gas are collected. Then, the purified gas is cooled and sent back to the blast furnace as circulating metallurgical gas. S2: Coupled Heat Exchange: First, energy is recovered from the high-pressure rich liquid at the bottom of absorption tower 1 using an amine liquid hydraulic turbine 17. Then, the rich liquid is sent to plate heat exchanger 6. The pressure at the bottom of absorption tower 1 is ≥1.6 MPa. Indirect heat exchange occurs between the rich liquid and circulating hot water from an 85-90℃ sintering ring cooler, heating the rich liquid from 45℃ to 77±2℃. The circulating hot water flow rate of the sintering ring cooler is 3000 m³ / h. 3 / h, rich solution flow rate is 3400m³ 3 / h, rich liquid pressure ≥1.8MPa, amine liquid side operating pressure drop ≤28kPa, if amine liquid heat exchange temperature <75℃, then adjust the circulating hot water flow rate of the sintering ring cooler to 3200m³ / h. 3 / h; When the amine liquid heat exchange temperature is >79℃, the circulating hot water flow rate of the sintering ring cooler is adjusted to 2800m³ / h. 3 / h, the rich liquid pressure is adjusted to 1.7MPa; after heat exchange and heating, the rich liquid enters the flash tank 8 for flash evaporation and releases gas containing H2 and CO. The released flash vapor flows from the top of the flash tank 8 into the gas compressor inlet manifold, mixes with the blast furnace gas, is compressed, and then sent back into the absorption tower 1. S3: Amine Regeneration: First, the rich liquid at the bottom of flash tank 8 is fed into regeneration tower 3, flowing downwards through the packing to further remove CO2 from the rich liquid. The rich liquid is regenerated in the upper part of regeneration tower 3, generating CO2-rich desorbed gas. The CO2 desorption rate is ≤3000 Nm³. 3 / h, then the CO2-rich desorbed gas is discharged from the top of the regeneration tower 3, cooled by the regeneration gas cooler 11, and enters the regeneration gas separator 12 for liquid separation. The gas separated by the regeneration gas separator 12 is sent to the venting system, while the condensed amine liquid and condensate are returned to the regeneration tower 3 by the reflux pump 13 to reduce solvent loss and maintain the system water balance. Then the lean liquid after decarbonization is collected at the bottom of the regeneration tower 3. The lean liquid at the bottom of the regeneration tower 3 enters the amine liquid side filter 14 through the second lean liquid pump 15 to filter impurities and corrosion products, and then enters the reboiler 9 from the bottom of the regeneration tower 3. Steam is introduced to heat the lean liquid, causing part of the amine liquid to vaporize and form a gas-liquid mixture. Then the gas-liquid mixture returns from the reboiler 9 to the lower section of the regeneration tower 3, thereby providing the high-temperature steam required for desorption in the regeneration tower 3.

[0022] In summary, this invention utilizes the closed-loop circulating hot water of an 85-90℃ sintering ring cooler as a heat source, and arranges the heat exchange unit in the high-pressure rich liquid section (≥1.6MPa) before the pressure reducing valve of the absorption tower. Relying on the synergistic effect of high pressure and low temperature, the CO2 pre-desorption capacity during the heating stage is reduced from 27000 Nm³. 3 / h decreased to 3000 Nm 3 Within a certain range, the investment in heat exchange equipment is significantly reduced. The system is equipped with a polyurethane-insulated waste heat distribution network, plate heat exchangers, and an online side-stream filtration structure for amine liquid, controlling the pressure drop on the amine liquid side to within 28 kPa, thus solving problems of corrosion, blockage, and cavitation. In terms of process operation, the entire process sequentially completes blast furnace gas CO2 capture, high-pressure rich liquid waste heat exchange and heating, flash pretreatment, regeneration tower desorption and regeneration, lean liquid filtration and circulation, and regeneration gas separation and recovery, maintaining a stable regeneration temperature of 77℃±2℃. The waste heat system can replace more than 40 tons of high-quality steam per hour, increasing the waste heat utilization rate to over 85%, and the overall system utilization rate can reach over 98.5%. Simultaneously, through the purification gas expander, the amine liquid hydraulic turbine recovery system for residual pressure, the multi-stage separator for recovering entrained amine liquid in the gas phase, and the flash vapor return to the main gas pipe for recovering combustible components, energy cascade utilization and solvent loss are achieved. Without affecting the decarbonization and purification effect of blast furnace gas, more than 100,000 tons of carbon emissions can be reduced annually.

[0023] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An energy-saving system for regenerating low-grade waste heat from hydrogen-rich carbon-circulating oxygen blast furnace sintering coupled with decarbonized amine liquid, characterized in that, The system includes an absorption tower (1), the outlet of which is connected to a purified gas separator (2), the inlet of which is connected to a regeneration tower (3), a lean liquid cooler (4) and a first lean liquid pump (5) connected in series on the pipeline connecting the absorption tower (1) and the regeneration tower (3), a plate heat exchanger (6) connected to the outlet of the absorption tower (1), a sintering ring cooler hot water pipe (7) and a flash tank (8) connected to the plate heat exchanger (6), and the bottom of the flash tank (8) The liquid phase outlet of the part is connected to the regeneration tower (3), and a reboiler (9) is connected to the regeneration tower (3). The heat source outlet of the reboiler (9) is equipped with a condensate separator (10). The gas phase outlet at the top of the regeneration tower (3) is connected in series with a regeneration gas cooler (11) and a regeneration gas separator (12). The liquid phase outlet of the regeneration gas separator (12) is connected to the regeneration tower (3). A reflux pump (13) is provided on the pipeline connecting the regeneration gas separator (12) and the regeneration tower (3).

2. The energy-saving system for regenerating low-grade waste heat coupled with decarbonized amine liquid in a hydrogen-rich carbon-circulating oxygen blast furnace sintering process, as described in claim 1, is characterized in that... The regeneration tower (3) is connected to an amine side filter (14), and a second lean liquid pump (15) is provided on the pipeline connecting the regeneration tower (3) and the amine side filter (14).

3. The energy-saving system for regenerating low-grade waste heat coupled with decarbonized amine liquid in a hydrogen-rich carbon-circulating oxygen blast furnace sintering process, as described in claim 1, is characterized in that... A purified gas expander (16) is installed on the pipeline connecting the absorption tower (1) and the purified gas separator (2), and an amine liquid hydraulic turbine (17) is installed on the pipeline connecting the absorption tower (1) and the plate heat exchanger (6).

4. The energy-saving system for regenerating low-grade waste heat coupled with decarbonized amine liquid in a hydrogen-rich carbon-circulating oxygen blast furnace sintering process, as described in claim 1, is characterized in that... The hot water pipe (7) of the sintered ring chiller is provided with a polyurethane insulation layer, and an outer protective pipe is provided outside the polyurethane insulation layer.

5. An energy-saving method for regenerating low-grade waste heat from hydrogen-rich carbon-circulating oxygen blast furnace sintering coupled with decarbonized amine liquid, characterized in that... Includes the following steps: S1: CO2 capture: First, the blast furnace gas is sent to the bottom of the absorption tower (1) so that the blast furnace gas passes through the packing layer inside the tower from bottom to top. At this time, the lean liquid in the regeneration tower (3) is cooled by the first lean liquid pump (5) and then transported to the top of the absorption tower (1) and sprayed from top to bottom. At the same time, it comes into countercurrent contact with the rising blast furnace gas. At this time, the lean liquid selectively absorbs CO2 in the blast furnace gas to generate rich liquid. S2: Coupling heat exchange: First, the high-pressure rich liquid at the bottom of the absorption tower (1) is recovered by the amine liquid hydraulic turbine (17). Then, the rich liquid is sent to the plate heat exchanger (6). The rich liquid is indirectly heated by the circulating hot water of the sintering ring cooler. After the heat exchange and heating, the rich liquid enters the flash tank (8) to flash and release gas containing H2 and CO. The released flash vapor flows from the top of the flash tank (8) into the gas compressor intake manifold. S3: Amine regeneration: First, the rich liquid at the bottom of the flash tank (8) is sent to the regeneration tower (3) so that the rich liquid is regenerated in the upper part of the regeneration tower (3). The regenerated lean liquid is collected at the bottom of the regeneration tower (3). Then, the lean liquid at the bottom of the regeneration tower (3) is sent to the amine side filter (14) through the second lean liquid pump (15) to filter impurities and corrosion products. After that, it enters the reboiler (9) from the bottom of the regeneration tower (3). Steam is introduced to heat the lean liquid, so that part of the amine liquid is vaporized to form a gas-liquid mixture. Then, the gas-liquid mixture returns from the reboiler (9) to the lower section of the regeneration tower (3) to provide the high-temperature steam required for desorption of the regeneration tower (3).

6. The energy-saving method for regenerating low-grade waste heat coupled with decarbonized amine liquid in a hydrogen-rich carbon-circulating oxygen blast furnace sintering process, as described in claim 5, is characterized in that... In S1, the purified coal gas after CO2 removal is discharged from the top of the absorption tower (1) and then passes through the purified gas expander (16) to recover the residual pressure of the purified coal gas. Then, the purified gas is collected by the purified gas separator (2) to collect the free water and condensate in the purified coal gas. After cooling, the purified coal gas is sent to the blast furnace as circulating metallurgical coal gas.

7. The energy-saving method for regenerating low-grade waste heat coupled with decarbonized amine liquid in a hydrogen-rich carbon-circulating oxygen blast furnace sintering process, as described in claim 5, is characterized in that... In S2, the circulating hot water temperature of the sintering ring cooling machine is 85-90℃, the rich liquid temperature before heat exchange is 45℃, the rich liquid temperature after heat exchange is 77±2℃, and the rich liquid flow is 3400m 3 / h.

8. The energy-saving method for regenerating low-grade waste heat coupled with decarbonized amine liquid in a hydrogen-rich carbon-circulating oxygen blast furnace sintering process, as described in claim 5, is characterized in that... In S2, if the amine liquid heat exchange temperature is <75℃, the circulating hot water flow rate of the sintering ring cooler should be adjusted to 3200 m³ / h. 3 / h; When the amine liquid heat exchange temperature is >79℃, the circulating hot water flow rate of the sintering ring cooler is adjusted to 2800m³ / h. 3 / h, the rich liquid pressure is adjusted to 1.7MPa.

9. The energy-saving method for regenerating low-grade waste heat coupled with decarbonized amine liquid in a hydrogen-rich carbon-circulating oxygen blast furnace sintering process, as described in claim 5, is characterized in that... In S3, the CO2-rich desorbed gas generated during rich liquid regeneration is cooled by the regeneration gas cooler (11) and then enters the regeneration gas separator (12) for liquid separation. The separated gas is sent to the venting system, while the condensate and condensate are returned to the regeneration tower (3) via the reflux pump (13); CO2 desorption capacity ≤3000 Nm³ 3 / h.

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