Energy-saving method for hydrogen-rich carbon circulating oxygen blast furnace gas decarbonization system

Abstract

The invention belongs to the technical field of removal of CO2 from metallurgical gas, and particularly discloses an energy-saving method for a hydrogen-rich carbon circulating oxygen blast furnace gas decarbonization system, which comprises the following steps: in the process of capturing CO2 in gas by a hydrogen-rich carbon circulating oxygen blast furnace, by utilizing external slag flushing water and heat in the system, steam required by a CO2 regeneration process is greatly reduced, and the CO2 regeneration process is reduced; the high-temperature spray circulating soft water of the compressor of the decarburization system is used for heating the decarburization solution in the regeneration tower, so that steam consumed by regeneration in the decarburization system can be reduced, circulating water consumed by a cooling compressor of an original system can be reduced, the consumption of the circulating water and the power consumption cost of the circulating water are reduced, and the energy consumption of the system is reduced. The latent heat of the increased saturated water can be increased by increasing the exhaust temperature of the compressor, the amount of saturated water entering the decarburization system can be increased by increasing the exhaust pressure of the compressor, the desalted water supplementing amount of the decarburization device can be reduced, and the energy consumption of the current hydrogen-rich carbon circulation oxygen blast furnace gas carbon dioxide trapping process can be greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of CO2 removal from metallurgical coal gas, and in particular to an energy-saving method for a hydrogen-rich carbon circulating oxygen blast furnace coal gas decarbonization system. Background Art

[0002] The hydrogen-rich carbon circulating oxygen blast furnace (HyCROF) is a smelting process that uses oxygen blast instead of traditional heated air blast. In order to compensate for the insufficient thermodynamic conditions required for the physical and chemical reactions in the blast furnace caused by full oxygen blast, reduction of N2 and sharp reduction in the amount of furnace gas, it is necessary to remove CO2 from the top gas to form a reducing gas medium with a higher concentration of reducing components (CO and H2) and spray it into the blast furnace.

[0003] In the prior art, one of the core processes of the hydrogen-rich carbon cycle oxygen blast furnace is the technology of removing CO2 from the top gas. The main process is that the top gas of the hydrogen-rich carbon cycle oxygen blast furnace is washed with dust removal water to reduce the gas temperature and dust content, and then pressurized by the compressor. The pressurized gas enters the lower part of the absorption tower, moves from bottom to top in the tower, and countercurrently contacts with the amine liquid lean liquid at the top of the absorption tower. The CO2 in the gas is absorbed by the amine liquid lean liquid to form purified gas, which is drawn out from the top of the tower and separated by the purified gas separator. The separated purified gas is sent to the gas heating furnace for heating and then sprayed into the hydrogen-rich carbon cycle oxygen blast furnace. The amine liquid rich liquid coming out of the bottom of the absorption tower enters the flash tank to realize pressure reduction and flash evaporation of dissolved CO2 and other gases. After flashing, the amine liquid rich liquid enters the regeneration tower from the bottom of the flash tank, and then is heated by the reboiler steam to regenerate the solution and CO2. The regenerated solution is pressurized and circulated to the absorption tower through the semi-lean liquid pump to absorb CO2 in a cycle, and the regenerated CO2 is captured and utilized.

[0004] The above decarbonization system is mainly based on power consumption and steam consumption. The power consumption is mainly used to pressurize blast furnace gas and semi-lean liquid pump to pressurize semi-lean liquid to provide the pressure working conditions required for the solution to absorb carbon dioxide. Therefore, in the decarbonization system, the power consumption of the compressor and the semi-lean liquid pump accounts for about 90% of the total power consumption. Steam is mainly used to heat the rich liquid in the regeneration tower to ensure the regeneration of its rich liquid. At present, there is no more reasonable utilization path for the waste heat of the compressor in the decarbonization system. Most of them only use circulating cooling water to cool the waste heat generated by the compressor, and the heat energy generated by the compressor is not fully utilized. At the same time, the residual pressure of the compressed high-pressure gas and the residual pressure of the flash tank are not fully utilized. In addition, the reboiler uses steam to heat the solution, the steam consumption is high, the temperature of the solution after steam heating in the regeneration tower is high, and the heat is not recovered. Therefore, it is necessary to adopt a method for energy-saving decarbonization of hydrogen-rich carbon circulating oxygen blast furnace gas device to reduce system energy consumption and supplement the heat required for reduction. Summary of the invention

[0005] The purpose of the present invention is to provide an energy-saving method for a hydrogen-rich carbon circulating oxygen blast furnace gas decarbonization system to solve the problems of waste of residual pressure of high-pressure gas and residual pressure entering a flash tank, high steam consumption when using steam to heat the solution in a reboiler, and insufficient recovery and utilization of heat and residual pressure in the entire decarbonization process.

[0006] To achieve the above object, the basic scheme provided by the present invention is: a method for energy saving in a hydrogen-rich carbon circulating oxygen blast furnace gas decarbonization system, comprising the following steps:

[0007] S1: The top gas of the hydrogen-rich carbon circulating oxygen blast furnace is dedusted and cooled by the dust removal unit. The dedusted and cooled top gas enters the compressor for pressurization. At the same time, the spray soft water in the spray soft water storage tank cools the compressor. The compressed gas and the spray soft water enter the compressor gas-liquid separator together for gas-liquid separation. The separated compressed gas is discharged from the top of the compressor gas-liquid separator, and the spray soft water is discharged from the bottom of the compressor gas-liquid separator.

[0008] S2: The liquid discharged from the bottom of the compressor gas-liquid separator enters the liquid spray soft water heat exchanger, and the compressed gas discharged from the top of the compressor gas-liquid separator enters the absorption tower and mixes with the amine lean liquid in the absorption tower. The amine lean liquid absorbs part of the CO2 in the compressed gas to form amine rich liquid. The compressed gas absorbs CO2 to form purified gas. The amine rich liquid is discharged from the bottom of the absorption tower, and the purified gas is discharged from the top of the absorption tower and divided into two paths;

[0009] S3: The amine rich liquid discharged from the bottom of the absorption tower enters the flash tank for flash evaporation. During this period, the high-pressure energy of the amine rich liquid is recovered through the hydraulic turbine device, and the high-pressure energy of the amine rich liquid is used to coaxially drive the semi-lean liquid pump;

[0010] S4: The flash steam after flash evaporation is discharged from the top of the flash tank and enters the gas network, and the amine liquid rich liquid after flash evaporation is discharged from the bottom of the flash tank and enters the regeneration tower;

[0011] S5: The rich amine liquid entering the regeneration tower is discharged from the upper end of the regeneration tower riser pipe, and is respectively heat exchanged through the reboiler, the slag water heat exchanger, and the liquid spray soft water heat exchanger. The heated rich amine liquid enters the lower end of the regeneration tower riser pipe to continue regeneration. At the same time, the condensate produced in the reboiler enters the condensate storage tank and is transported to the gas heater for heat exchange with the purified gas.

[0012] S6: The amine rich liquid after regeneration in the regeneration tower becomes semi-lean liquid, which is discharged from the bottom of the regeneration tower. After heat exchange in the semi-lean liquid heat exchanger, it enters the absorption tower to continue to adsorb CO2. The regenerated gas in the regeneration tower is discharged from the top of the regeneration tower. After passing through the regeneration gas cooler, the temperature of the regeneration gas is reduced from 50-60℃ to 30-40℃. The regeneration gas after cooling enters the regeneration gas gas-liquid separator for gas-liquid separation. The separated solution is discharged from the bottom of the regeneration gas gas-liquid separator and enters the top of the regeneration tower for recycling. The separated CO2 is discharged from the top of the regeneration gas gas-liquid separator and enters the gas storage tank.

[0013] The working principle of the present invention is as follows: the coal gas at the top of the hydrogen-rich carbon circulating oxygen blast furnace is subjected to dust removal and water washing to reduce the coal gas temperature and dust content, and then is pressurized by a compressor. At this time, the compressor generates a large amount of heat when doing work, and it is necessary to cool the compressor by spraying soft water, and the cooling water after heat exchange is used to exchange heat with the rich liquid of the subsequent regeneration tower amine liquid; the pressurized coal gas enters from the lower part of the absorption tower, moves from bottom to top in the tower, and contacts with the composite solution at the top of the absorption tower in reverse order to transfer heat and mass, CO2 in the gas is absorbed, and the purified reducing gas is drawn out from the top of the tower, and the purified reducing gas is separated from the entrained droplets by the purified gas separator and sent to the gas heating furnace for heating and then sprayed into the hydrogen-rich carbon circulating oxygen blast furnace; the rich liquid flowing out from the bottom of the absorption tower enters the flash tank to reduce the pressure and flash out the dissolved CO2 and other gases, and the rich liquid at the bottom of the flash tank enters the regeneration tower, and the rich liquid in the regeneration tower is heated by slag flushing water, liquid soft water spraying, and a reboiler to regenerate the solution, and the condensate after the steam used to heat the rich liquid is condensed is transported to the gas heater for heat exchange.

[0014] The beneficial effects of the present invention are as follows: in the process of capturing carbon dioxide in coal gas by a hydrogen-rich carbon circulating oxygen blast furnace, the system consumes a large amount of energy media. By utilizing external slag flushing water and heat inside the system, the steam required for the CO2 regeneration process can be greatly reduced. By using the high-temperature liquid spray circulating soft water of the decarbonization system compressor to heat the decarbonization solution in the regeneration tower, the steam consumed by the regeneration in the decarbonization system can be greatly reduced. The large amount of circulating water consumed by the original system cooling compressor can be greatly reduced, thereby reducing the consumption of circulating water and the electricity consumption cost of circulating water. Increasing the exhaust temperature of the compressor can increase the sensible heat brought into the absorption tower by the coal gas and the latent heat of the saturated water increased by the temperature increase. By increasing the exhaust pressure of the compressor, the amount of saturated water entering the decarbonization system can be increased, the amount of desalted water replenished in the decarbonization device can be reduced, and the energy consumption of the current hydrogen-rich carbon circulating oxygen blast furnace coal gas carbon dioxide capture process can be greatly reduced. The invention has broad application prospects.

[0015] Scheme 2 is the preferred basic scheme. In step S2, the purified gas is discharged from the top of the absorption tower and is divided into a priority route and a secondary route:

[0016] Priority route: The purified gas is led out from the top of the absorption tower, and the temperature of the purified gas is heated from 40-50°C to 80-100°C by a gas heater. The heated purified gas enters the expander;

[0017] Secondary route: Add a branch from the priority route and use a three-valve group to reduce the pressure of the purified gas from 1300-1600KPa to 350-500KPa. The decompressed purified gas enters the purified gas separation tank and is sent to the gas heating furnace system after gas-liquid separation. The temperature of the purified gas is heated from 40-50℃ to 900-1200℃. The heated purified gas enters the hydrogen-rich carbon circulating oxygen blast furnace.

[0018] Option 3: This is the preferred option of Option 2. The expander is coaxially connected to the compressor through a clutch. The purified gas entering the expander is divided into an energy supply part and a circulation part.

[0019] Energy supply part: After the purified gas enters the expander, the expander absorbs the high-pressure energy of the purified gas and is driven coaxially with the compressor;

[0020] Circulation part: When the energy of the purified gas supplying energy to the expander is sufficient, the redundant purified gas is decompressed by the expander, and the pressure of the redundant purified gas is reduced from 1300-1600KPa to 300-500Kpa. The decompressed purified gas is discharged from the expander and enters the purified gas separation tank. The separated purified gas enters the gas heating furnace for heating, and then is sprayed into the hydrogen-rich carbon circulating oxygen blast furnace for recycling.

[0021] Option 4 is the preferred option of Option 3. The gas heating furnace heats the purified gas from 80-100°C to 900-1200°C.

[0022] Scheme 5, which is the preferred basic scheme, the specific process of heating the rich amine solution in the regeneration tower in step S5 is as follows:

[0023] Before heating: the amine rich liquid is discharged from the upper end of the regeneration tower riser pipe. The discharged amine rich liquid is divided into two paths. One path enters the slag flushing water heat exchanger to exchange heat with the high-temperature slag flushing water, and the other path enters the liquid spraying soft water heat exchanger to exchange heat with the 85°C compressor liquid spraying soft water. After heat exchange in the slag flushing water heat exchanger and the liquid spraying soft water heat exchanger, the temperature of the amine rich liquid rises from 60-68°C to between 70-78°C.

[0024] After heating: If the temperature of the amine rich liquid after heat exchange through the slag water heat exchanger and the spray softening water heat exchanger is between 70-78°C, it will directly enter from the lower end of the regeneration tower; if the temperature of the amine rich liquid after heat exchange through the slag water heat exchanger and the spray softening water heat exchanger does not reach 70°C, open the reboiler pipeline valve, and the amine rich liquid will enter the reboiler for secondary heating. After the temperature of the amine rich liquid reaches 70°C, it will be discharged from the top of the reboiler and enter from the lower end of the regeneration tower.

[0025] Scheme 6, which is the preferred basic scheme, in step S6, the specific method of semi-lean liquid heat exchange is:

[0026] When heat storage is required, the valve of the heating unit is fully opened, the valve of the soft water cooling unit is fully closed, and the semi-lean liquid enters the semi-lean liquid heat exchanger to exchange heat with the cold water in the heating unit, reducing the temperature of the semi-lean liquid from 60-68°C to 48-58°C;

[0027] When heat storage is not required, the heating unit valve is fully closed and the soft water cooling unit valve is fully opened. The semi-lean liquid enters the semi-lean liquid heat exchanger and exchanges heat with the cold water in the soft water cooling unit, reducing the temperature of the semi-lean liquid from 60-68°C to 48-58°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of an energy-saving method for a hydrogen-rich carbon circulating oxygen blast furnace gas decarbonization system of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below through specific embodiments:

[0030] The figure marks in the drawings of the specification include: 1. Hydrogen-rich carbon cycle oxygen blast furnace, 2. Compressor, 3. Liquid spray soft water storage tank, 4. Compressor gas-liquid separator, 5. Liquid spray soft water heat exchanger, 6. Absorption tower, 7. Flash tank, 8. Hydraulic turbine device, 9. Semi-lean liquid pump, 10. Gas pipeline network, 11. Regeneration tower, 12. Reboiler, 13. Slag flushing water heat exchanger, 14. Heating unit, 15. Condensate storage tank, 16. Gas heater, 17. Semi-lean liquid heat exchanger, 18. Regeneration gas cooler, 19. Regeneration gas gas-liquid separator, 20. Gas storage tank, 21. Expander, 22. Three-valve group, 23. Purified gas separation tank, 24. Gas heating furnace, 25. Reboiler pipeline valve, 26. Heating unit valve, 27. Soft water cooling unit valve, 28. Soft water cooling unit.

[0031] Example

[0032] Implementation example Figure 1 As shown: A method for energy saving in a hydrogen-rich carbon circulating oxygen blast furnace gas decarbonization system, comprising the following steps:

[0033] S1: The top gas of the hydrogen-rich carbon circulating oxygen blast furnace 1 is dedusted and cooled by the dust removal unit. The dedusted and cooled top gas enters the compressor 2 for pressurization. At the same time, the sprayed soft water in the sprayed soft water storage tank 3 cools the compressor 2. The compressed gas and the sprayed soft water enter the compressor gas-liquid separator 4 for gas-liquid separation. The separated compressed gas is discharged from the top of the compressor gas-liquid separator 4, and the sprayed soft water is discharged from the bottom of the compressor gas-liquid separator 4.

[0034] S2: The liquid discharged from the bottom of the compressor gas-liquid separator 4 enters the liquid spray soft water heat exchanger 5, and the compressed gas discharged from the top of the compressor gas-liquid separator 4 enters the absorption tower 6 and mixes with the amine liquid lean liquid in the absorption tower 6. The amine liquid lean liquid absorbs part of the CO2 in the compressed gas to form an amine liquid rich liquid. The compressed gas absorbs CO2 to form purified gas. The amine liquid rich liquid is discharged from the bottom of the absorption tower 6, and the purified gas is discharged from the top of the absorption tower 6 and divided into two routes. After being discharged from the top of the absorption tower 6, the purified gas is divided into a priority route and a secondary route:

[0035] Priority route: The purified gas is led out from the top of the absorption tower 6, and the purified gas temperature is heated from 40-50°C to 80-100°C by the gas heater 16. The heated purified gas enters the expander 21.

[0036] Secondary route: add a branch from the priority route, and use the three-valve group 22 to reduce the pressure of the purified gas from 1300-1600KPa to 350-500KPa. The purified gas after decompression enters the purified gas separation tank 23, and is sent to the gas heating furnace 24 after gas-liquid separation. The temperature of the purified gas is heated from 40-50℃ to 900-1200℃. The heated purified gas enters the hydrogen-rich carbon circulating oxygen blast furnace 1.

[0037] The expander 21 is coaxially connected to the compressor 2 through the clutch 22. The purified gas entering the expander 21 is divided into an energy supply part and a circulation part:

[0038] Energy supply part: After the purified gas enters the expander 21, the expander 21 absorbs the high-pressure energy of the purified gas and drives coaxially with the compressor 2.

[0039] Circulation part: when the purified gas energy for the expander 21 is sufficient, the redundant purified gas is decompressed by the expander 21, and the pressure of the redundant purified gas is reduced from 1300-1600KPa to 300-500KPa. The decompressed purified gas is discharged from the expander 21 and enters the purified gas separation tank 23. The separated purified gas enters the gas heating furnace 24 for heating, and then is sprayed into the hydrogen-rich carbon circulating oxygen blast furnace 1 for recycling;

[0040] S3: the amine rich liquid discharged from the bottom of the absorption tower 6 enters the flash tank 7 for flash evaporation, during which the high-pressure energy of the amine rich liquid is recovered by the hydraulic turbine device 8, and the high-pressure energy of the amine rich liquid is used to coaxially drive the semi-lean liquid pump 9;

[0041] S4: the flash steam after flash evaporation is discharged from the top of the flash tank 7 and enters the gas pipe network 10, and the amine liquid rich liquid after flash evaporation is discharged from the bottom of the flash tank 7 and enters the regeneration tower 11;

[0042] S5: The rich amine liquid entering the regeneration tower 11 is discharged from the upper end of the gas riser of the regeneration tower 11, and is respectively heat exchanged through the reboiler 12, the slag water heat exchanger 13, and the liquid spraying soft water heat exchanger 5. The specific process of heating the rich amine liquid in the regeneration tower 11 is as follows:

[0043] Before heating: the amine rich liquid is discharged from the upper end of the gas riser of the regeneration tower 11. The discharged amine rich liquid is divided into two paths. One path enters the slag flushing water heat exchanger 13 to exchange heat with the high-temperature slag flushing water, and the other path enters the liquid spraying soft water heat exchanger 5 to exchange heat with the 85°C compressor 2 liquid spraying soft water. After the slag flushing water heat exchanger 13 and the liquid spraying soft water heat exchanger 5, the temperature of the amine rich liquid rises from 60-68°C to between 70-78°C.

[0044] After heating: if the temperature of the amine rich liquid after heat exchange with the slag water heat exchanger 13 and the liquid spraying softening water heat exchanger 5 is between 70-78°C, it directly enters from the lower end of the regeneration tower 11; if the temperature of the amine rich liquid after heat exchange with the slag water heat exchanger 13 and the liquid spraying softening water heat exchanger 5 does not reach 70°C, the reboiler pipeline valve 25 is opened, and the amine rich liquid enters the reboiler 12 for secondary heating. After the temperature of the amine rich liquid reaches 70°C, it is discharged from the top of the reboiler 12 and enters from the lower end of the regeneration tower 11.

[0045] The heated amine liquid rich liquid enters the lower end of the gas riser of the regeneration tower 11 to continue regeneration, while the condensate produced in the reboiler 12 enters the condensate storage tank 15 and is transported to the gas heater 16 for heat exchange with the purified gas;

[0046] S6: The amine-rich liquid after regeneration in the regeneration tower 11 becomes a semi-lean liquid, which is discharged from the bottom of the regeneration tower 11 and is heat-exchanged in the semi-lean liquid heat exchanger 17. The specific method of heat-exchanging the semi-lean liquid is as follows:

[0047] When heat storage is required, the heating unit valve 26 is fully opened, the soft water cooling unit valve 27 is fully closed, and the semi-lean liquid enters the semi-lean liquid heat exchanger 17 to exchange heat with the cold water in the heating unit 14, reducing the temperature of the semi-lean liquid from 60-68°C to 48-58°C;

[0048] When heat storage is not required, the heating unit valve 26 is fully closed, the soft water cooling unit valve 27 is fully opened, and the semi-lean liquid enters the semi-lean liquid heat exchanger 17 to exchange heat with the cold water in the soft water cooling unit 28, reducing the temperature of the semi-lean liquid from 60-68°C to 48-58°C.

[0049] The regenerated gas enters the absorption tower 6 to continue to adsorb CO2, and the regenerated gas in the regeneration tower 11 is discharged from the top of the regeneration tower 11. After passing through the regeneration gas cooler 18, the temperature of the regeneration gas is reduced from 50-60°C to 30-40°C. The cooled regeneration gas enters the regeneration gas-liquid separator 19 for gas-liquid separation. The separated solution is discharged from the bottom of the regeneration gas-liquid separator 19 and enters the top of the regeneration tower 11 for recycling. The separated CO2 is discharged from the top of the regeneration gas-liquid separator 19 and enters the gas storage tank 20.

[0050] The implementation method of this embodiment is:

[0051] First, the top gas of the hydrogen-rich carbon circulating oxygen blast furnace 1 passes through the dust removal unit for dust removal and cooling. The top gas after dust removal and cooling enters the compressor 2 for pressurization. At the same time, the spray soft water in the spray soft water storage tank 3 cools the compressor 2. The compressed compressed gas and the spray soft water enter the compressor gas-liquid separator 4 for gas-liquid separation. The separated compressed gas is discharged from the top of the compressor gas-liquid separator 4, and the spray soft water is discharged from the bottom of the compressor gas-liquid separator 4. The liquid discharged from the bottom of the compressor gas-liquid separator 4 enters the spray soft water heat exchanger 5. The compressed gas discharged from the top of the compressor gas-liquid separator 4 enters the absorption tower 6 and is mixed with the amine liquid lean liquid in the absorption tower 6. The amine liquid lean liquid absorbs part of the CO2 in the compressed gas to form amine liquid rich liquid. The compressed gas is formed after absorbing CO2. The amine liquid rich liquid is discharged from the bottom of the absorption tower 6. The purified gas is discharged from the top of the absorption tower 6 and is divided into two routes. After the purified gas is discharged from the top of the absorption tower 6, it is divided into a priority route and a secondary route:

[0052] Priority route: The purified gas is led out from the top of the absorption tower 6, and the purified gas temperature is heated from 40-50°C to 80-100°C by the gas heater 16. The heated purified gas enters the expander 21.

[0053] Secondary route: add a branch from the priority route, and use the three-valve group 22 to reduce the pressure of the purified gas from 1300-1600KPa to 350-500KPa. The purified gas after decompression enters the purified gas separation tank 23, and is sent to the gas heating furnace 24 after gas-liquid separation. The temperature of the purified gas is heated from 40-50℃ to 900-1200℃. The heated purified gas enters the hydrogen-rich carbon circulating oxygen blast furnace 1.

[0054] The expander 21 is coaxially connected to the compressor 2 through the clutch 22. The purified gas entering the expander 21 is divided into an energy supply part and a circulation part:

[0055] Energy supply part: After the purified gas enters the expander 21, the expander 21 absorbs the high-pressure energy of the purified gas and drives coaxially with the compressor 2.

[0056] Circulation part: when the purified gas energy for the expander 21 is sufficient, the redundant purified gas is decompressed by the expander 21, and the pressure of the redundant purified gas is reduced from 1300-1600KPa to 300-500Kpa. The purified gas after decompression is discharged from the expander 21 and enters the purified gas separation tank 23. The separated purified gas enters the gas heating furnace 24 for heating, and is sprayed into the hydrogen-rich carbon circulating oxygen blast furnace 1 for recycling after heating. The amine liquid rich liquid discharged from the bottom of the absorption tower 6 enters the flash tank 7 for flash evaporation. During this period, the high-pressure energy of the amine liquid rich liquid is recovered by the hydraulic turbine device 8. The high-pressure energy of the amine liquid rich liquid is coaxially driven with the semi-lean liquid pump 9. The flash steam after flash evaporation is discharged from the top of the flash tank 7 and enters the gas pipe network 10. The amine liquid rich liquid after flash evaporation is discharged from the bottom of the flash tank 7 and enters the regeneration tower 11.

[0057] S5: The rich amine liquid entering the regeneration tower 11 is discharged from the upper end of the gas riser of the regeneration tower 11, and is respectively heat exchanged through the reboiler 12, the slag water heat exchanger 13, and the liquid spray soft water heat exchanger 5. The specific process of heating the rich amine liquid in the regeneration tower 11 is as follows:

[0058] Before heating: the amine rich liquid is discharged from the upper end of the gas riser of the regeneration tower 11. The discharged amine rich liquid is divided into two paths. One path enters the slag flushing water heat exchanger 13 to exchange heat with the high-temperature slag flushing water, and the other path enters the liquid spraying soft water heat exchanger 5 to exchange heat with the 85°C compressor 2 liquid spraying soft water. After the slag flushing water heat exchanger 13 and the liquid spraying soft water heat exchanger 5, the temperature of the amine rich liquid rises from 60-68°C to between 70-78°C.

[0059] After heating: if the temperature of the amine rich liquid after heat exchange with the slag water heat exchanger 13 and the liquid spraying softening water heat exchanger 5 is between 70-78°C, it directly enters from the lower end of the regeneration tower 11; if the temperature of the amine rich liquid after heat exchange with the slag water heat exchanger 13 and the liquid spraying softening water heat exchanger 5 does not reach 70°C, the reboiler pipeline valve 25 is opened, and the amine rich liquid enters the reboiler 12 for secondary heating. After the temperature of the amine rich liquid reaches 70°C, it is discharged from the top of the reboiler 12 and enters from the lower end of the regeneration tower 11.

[0060] The heated amine liquid rich liquid enters the lower end of the gas riser of the regeneration tower 11 to continue regeneration. At the same time, the condensate produced in the reboiler 12 enters the condensate storage tank 15 and is transported to the gas heater 16 to exchange heat with the purified gas. The amine liquid rich liquid regenerated by the regeneration tower 11 becomes a semi-lean liquid, which is discharged from the bottom of the regeneration tower 11 and is heat exchanged by the semi-lean liquid heat exchanger 17. The specific method of heat exchange of the semi-lean liquid is as follows:

[0061] When heat storage is required, the heating unit valve 26 is fully opened, the soft water cooling unit valve 27 is fully closed, and the semi-lean liquid enters the semi-lean liquid heat exchanger 17 to exchange heat with the cold water in the heating unit 14, reducing the temperature of the semi-lean liquid from 60-68°C to 48-58°C;

[0062] When heat storage is not required, the heating unit valve 26 is fully closed, the soft water cooling unit valve 27 is fully opened, and the semi-lean liquid enters the semi-lean liquid heat exchanger 17 to exchange heat with the cold water in the soft water cooling unit 28, reducing the temperature of the semi-lean liquid from 60-68°C to 48-58°C.

[0063] The regenerated gas enters the absorption tower 6 to continue to adsorb CO2, and the regenerated gas in the regeneration tower 11 is discharged from the top of the regeneration tower 11. After passing through the regeneration gas cooler 18, the temperature of the regeneration gas is reduced from 50-60°C to 30-40°C. The cooled regeneration gas enters the regeneration gas-liquid separator 19 for gas-liquid separation. The separated solution is discharged from the bottom of the regeneration gas-liquid separator 19 and enters the top of the regeneration tower 11 for recycling. The separated CO2 is discharged from the top of the regeneration gas-liquid separator 19 and enters the gas storage tank 20.

[0064] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for energy saving in a hydrogen-rich carbon cycle oxygen blast furnace gas decarbonization system, characterized in that: The following steps are involved: S1: The top gas of the hydrogen-rich carbon circulating oxygen blast furnace (1) is dedusted and cooled by a dust removal unit. The dedusted and cooled top gas enters a compressor (2) for pressurization. At the same time, the soft water in the soft water storage tank (3) cools the compressor (2). The compressed gas and the soft water enter a compressor gas-liquid separator (4) for gas-liquid separation. The separated compressed gas is discharged from the top of the compressor gas-liquid separator (4), and the soft water is discharged from the bottom of the compressor gas-liquid separator (4). S2: The liquid discharged from the bottom of the compressor gas-liquid separator (4) enters the liquid spray soft water heat exchanger (5), and the compressed coal gas discharged from the top of the compressor gas-liquid separator (4) enters the absorption tower (6) and is mixed with the amine liquid lean liquid in the absorption tower (6). The amine liquid lean liquid absorbs part of the CO2 in the compressed coal gas to form an amine liquid rich liquid. The compressed coal gas absorbs CO2 to form purified gas. The amine liquid rich liquid is discharged from the bottom of the absorption tower (6), and the purified gas is discharged from the top of the absorption tower (6) and is divided into two paths; S3: The amine rich liquid discharged from the bottom of the absorption tower (6) enters the flash tank (7) for flash evaporation, during which the high-pressure energy of the amine rich liquid is recovered through the hydraulic turbine device (8), and the high-pressure energy of the amine rich liquid is used to coaxially drive the semi-lean liquid pump (9); S4: the flash steam after flash evaporation is discharged from the top of the flash tank (7) and enters the gas pipe network (10), and the amine liquid rich liquid after flash evaporation is discharged from the bottom of the flash tank (7) and enters the regeneration tower (11); S5: the rich amine liquid entering the regeneration tower (11) is discharged from the upper end of the gas riser of the regeneration tower (11), and is respectively heat exchanged through the reboiler (12), the slag flushing water heat exchanger (13), and the liquid spraying soft water heat exchanger (5). The heated rich amine liquid enters the lower end of the gas riser of the regeneration tower (11) to continue regeneration. At the same time, the condensate generated in the reboiler (12) enters the condensate storage tank (15) and is transported to the coal gas heater (16) to exchange heat with the purified gas. S6: The amine-rich liquid after regeneration in the regeneration tower (11) becomes a semi-lean liquid. The semi-lean liquid is discharged from the bottom of the regeneration tower (11), and after heat exchange in the semi-lean liquid heat exchanger (17), enters the absorption tower (6) to continue to adsorb CO2. The regenerated gas in the regeneration tower (11) is discharged from the top of the regeneration tower (11). After passing through the regeneration gas cooler (18), the temperature of the regeneration gas is reduced from 50-60°C to 30-40°C. The cooled regeneration gas enters the regeneration gas-liquid separator (19) for gas-liquid separation. The separated solution is discharged from the bottom of the regeneration gas-liquid separator (19) and enters the top of the regeneration tower (11) for recycling. The separated CO2 is discharged from the top of the regeneration gas-liquid separator (19) and enters the gas storage tank (20).

2. The method for energy saving of a hydrogen-rich carbon cycle oxygen blast furnace gas decarbonization system according to claim 1, characterized in that: In step S2, the purified gas is discharged from the top of the absorption tower (6) and is divided into a priority route and a secondary route: Priority route: The purified gas is led out from the top of the absorption tower (6), and the purified gas is heated from 40-50°C to 80-100°C by a gas heater (16). The heated purified gas enters an expander (21) to perform work; Secondary route: A branch is added to the priority route, and the pressure of the purified gas is reduced from 1300-1600 KPa to 350-500 KPa using a three-valve group (22). The depressurized purified gas enters the purified gas separation tank (23), and is sent to the coal gas heating furnace (24) after gas-liquid separation. The heated purified gas enters the hydrogen-rich carbon circulating oxygen blast furnace (1).

3. The method for energy saving of a hydrogen-rich carbon cycle oxygen blast furnace gas decarbonization system according to claim 2, characterized in that: The expander (21) is coaxially connected to the compressor (2) via a clutch (22). The purified gas entering the expander (21) is divided into an energy supply part and a circulation part. Energy supply part: After the purified gas enters the expander (21), the expander (21) absorbs the high-pressure energy of the purified gas and is driven coaxially with the compressor (2); Circulation part: When the purified gas energy for supplying energy to the expander (21) is sufficient, the redundant purified gas is decompressed by the expander (21), and the pressure of the redundant purified gas is reduced from 1300-1600 KPa to 300-500 KPa. The decompressed purified gas is discharged from the expander (21) and enters the purified gas separation tank (23). The separated purified gas enters the coal gas heating furnace (24) for heating, and after heating, is sprayed into the hydrogen-rich carbon circulating oxygen blast furnace (1) for recycling.

4. The method for energy saving of a hydrogen-rich carbon cycle oxygen blast furnace gas decarbonization system according to claim 3 is characterized in that: The gas heating furnace (24) heats the purified gas from 80-100°C to 900-1200°C.

5. The method for energy saving of a hydrogen-rich carbon circulating oxygen blast furnace gas decarbonization system according to claim 1, characterized in that: The specific process of heating the rich amine solution in the regeneration tower (11) in step S5 is as follows: Before heating: the amine rich liquid is discharged from the upper end of the gas riser of the regeneration tower (11), and the discharged amine rich liquid is divided into two paths, one path enters the slag flushing water heat exchanger (13) to exchange heat with the high-temperature slag flushing water, and the other path enters the liquid spraying soft water heat exchanger (5) to exchange heat with the 85°C liquid spraying soft water of the compressor (2). After the heat exchange in the slag flushing water heat exchanger (13) and the liquid spraying soft water heat exchanger (5), the temperature of the amine rich liquid is increased from 60-68°C to between 70-78°C; After heating: if the temperature of the amine rich liquid after heat exchange through the slag water heat exchanger (13) and the liquid spraying softening water heat exchanger (5) is between 70-78°C, it directly enters from the lower end of the regeneration tower (11); if the temperature of the amine rich liquid after heat exchange through the slag water heat exchanger (13) and the liquid spraying softening water heat exchanger (5) does not reach 70°C, the reboiler pipeline valve (25) is opened, and the amine rich liquid enters the reboiler (12) for secondary heating. After the temperature of the amine rich liquid reaches 70°C, it is discharged from the top of the reboiler (12) and enters from the lower end of the regeneration tower (11).

6. The method for energy saving of a hydrogen-rich carbon circulating oxygen blast furnace gas decarbonization system according to claim 1, characterized in that: In step S6, the specific method of semi-lean liquid heat exchange is: When heat storage is required, the heating unit valve (26) is fully opened, the soft water cooling unit valve (27) is fully closed, and the semi-lean liquid enters the semi-lean liquid heat exchanger (17) to exchange heat with the cold water in the heating unit (14), reducing the temperature of the semi-lean liquid from 60-68°C to 48-58°C; When heat storage is not required, the heating unit valve (26) is fully closed, the soft water cooling unit valve (27) is fully opened, and the semi-lean liquid enters the semi-lean liquid heat exchanger (17) to exchange heat with the cold water in the soft water cooling unit (28), thereby reducing the temperature of the semi-lean liquid from 60-68° C. to 48-58° C.

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