System and method for heating CO2 and inputting CO2 into blast furnace to participate in smelting

Abstract

The invention discloses a system and a method for heating CO2 and inputting the CO2 into a blast furnace to participate in smelting, belongs to the technical field of blast furnace smelting, and aims to reduce adverse effects caused by the fact that CO2 enters the blast furnace in the prior art. The system for heating the CO2 and inputting the CO2 into the blast furnace to participate in smelting comprises a heating furnace (30), the blast furnace (31), a blast furnace flue gas CO2 separating and capturing device (32), a buffer tank (33), a heat exchanger (34), a hot blast stove flue gas CO2 separating and capturing device (35) and a hot blast stove (40). According to the system and method for heating CO2 and inputting CO2 into the blast furnace to participate in smelting, waste heat in flue gas of the heating furnace is fully utilized to heat CO2 generated by the blast furnace and CO2 in flue gas of the hot blast furnace after heat exchange, and then the CO2 and the flue gas are fed into the heating furnace, so that the influence of CO2 input into the heating furnace on temperature fluctuation is reduced, and the stability of the temperature of a tuyere rotation area of the blast furnace is maintained; and indirect reduction reaction in the furnace is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace smelting, and specifically to a system for heating CO2 and inputting it into a blast furnace for smelting, and also to a method for heating CO2 and inputting it into a blast furnace for smelting. Background Art

[0002] The main technology for realizing CO2 recycling in the ironmaking process is to inject CO2 into the blast furnace to participate in smelting. The CO2 injected into the blast furnace reacts with C to generate CO to promote indirect reduction in the furnace. However, there are currently two difficulties in injecting CO2 into the blast furnace: first, the pressure in the blast furnace is high, and the cost of pressurized CO2 injection is high, which poses a safety hazard; second, the reaction of CO2 and C in the blast furnace is a strong endothermic reaction, which will cause fluctuations in the temperature balance in the furnace and affect the smooth operation of the blast furnace.

[0003] For example, Chinese patent document CN115820954A, published on March 21, 2023, discloses "A blast furnace injection CO2-biochar tempering co-production carbon emission reduction system and application process", which introduces that a mixed gas source of CO2, O2 and air is sent into the blast furnace through a hot blast furnace to participate in smelting, solving the problem of high pressure injection difficulty in the blast furnace. However, the problem is that when CO2 is mixed into the hot blast furnace, the temperature of the hot air entering the blast furnace is reduced, and the reaction of CO2 and carbon is a strong endothermic reaction, which will cause the temperature of the tuyere vortex zone to decrease, reduce the combustion performance of coal powder, make it difficult to increase the coal ratio, increase the coke ratio, increase the cost of ironmaking, and cause energy waste. Summary of the invention

[0004] In order to reduce the adverse effects of the above-mentioned CO2 entering the blast furnace, the present invention provides a system and method for heating CO2 and inputting it into the blast furnace for smelting. The system and method for heating CO2 and inputting it into the blast furnace for smelting fully utilize the waste heat in the flue gas of the heating furnace to heat up the CO2 generated by the blast furnace and the CO2 in the flue gas of the hot blast furnace after heat exchange and then send them into the heating furnace, thereby reducing the impact of the CO2 input into the heating furnace on its temperature fluctuation, maintaining the stability of the temperature in the vortex zone of the blast furnace tuyere, and being beneficial to the indirect reduction reaction in the furnace.

[0005] The technical solution adopted by the embodiment of the present invention to solve the technical problem is:

[0006] A system for heating CO2 and inputting it into a blast furnace for smelting, comprising a heating furnace, a blast furnace, a blast furnace flue gas CO2 separation and capture device, a buffer tank, a heat exchanger, a hot blast furnace flue gas CO2 separation and capture device and a hot blast furnace;

[0007] The blast furnace flue gas generated by the blast furnace can enter the blast furnace flue gas CO2 separation and capture device for separation, and the CO2 gas separated by the blast furnace flue gas CO2 separation and capture device can enter the buffer tank;

[0008] The high-temperature flue gas generated by the heating furnace can enter the heat exchanger to release heat;

[0009] The blast furnace flue gas generated by the hot blast furnace can be separated in the hot blast furnace flue gas CO2 separation and capture device, and the CO2 gas separated by the hot blast furnace flue gas CO2 separation and capture device can enter the buffer tank;

[0010] The CO2 gas in the buffer tank can enter the heat exchanger to absorb heat for the first time;

[0011] After absorbing heat for the first time, the CO2 gas can enter the heating furnace to absorb heat for the second time;

[0012] The CO2 gas after the second heat absorption can enter the blast furnace to participate in smelting.

[0013] A method for heating CO2 and inputting it into a blast furnace for smelting, wherein the method for heating CO2 and inputting it into a blast furnace for smelting adopts the above-mentioned system for heating CO2 and inputting it into a blast furnace for smelting, and the method for heating CO2 and inputting it into a blast furnace for smelting comprises the following steps in sequence:

[0014] The blast furnace flue gas generated by the blast furnace enters the blast furnace flue gas CO2 separation and capture device for separation, and the CO2 gas separated by the blast furnace flue gas CO2 separation and capture device enters the buffer tank;

[0015] The high-temperature flue gas generated by the combustion of air and gas during heating enters the heat exchanger to release heat;

[0016] The blast furnace flue gas generated by the hot blast furnace enters the hot blast furnace flue gas CO2 separation and capture device for separation, and the CO2 gas separated by the hot blast furnace flue gas CO2 separation and capture device enters the buffer tank;

[0017] The CO2 gas in the buffer tank enters the heat exchanger and absorbs heat for the first time;

[0018] The CO2 gas after the first heat absorption enters the heating furnace, and the air and fuel gas enter the heating furnace for combustion. The CO2 gas after the first heat absorption absorbs heat for the second time.

[0019] The CO2 gas after the second heat absorption enters the blast furnace to participate in smelting.

[0020] The beneficial effects of the embodiments of the present invention are:

[0021] 1. A two-stage heating method is adopted. The first stage heating uses the waste heat in the flue gas generated by the combustion of air and gas to heat CO2, thereby improving the recycling rate of energy; the second stage heating uses a heating furnace to heat CO2 to the temperature required for smelting in a blast furnace. The consumption of air and gas is reduced through graded heating, thereby realizing the recycling of energy.

[0022] 2. The CO2 in the flue gas after heat exchange in the hot blast furnace and the CO2 in the blast furnace smelting process are integrated together and sprayed into the blast furnace to participate in smelting, which improves the utilization rate of coal powder, promotes the indirect reduction reaction in the furnace, and reduces the carbon consumption and carbon emissions of blast furnace smelting.

[0023] 3. The heated CO2 is sprayed into the blast furnace, which compensates for the temperature fluctuation caused by the strong endothermic reaction of CO2 and C in the tuyere whirlpool area, ensures the stability of the theoretical combustion temperature of the tuyere, and is conducive to the smooth operation of the furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 It is a schematic diagram of the system for heating CO2 and inputting it into a blast furnace for smelting according to the present invention.

[0026] The following are the descriptions of the reference numerals:

[0027] 1. Gas release valve; 2. Gas combustion valve; 3. Gas shut-off valve; 4. Gas regulating valve; 5. CO2 shut-off valve; 6. Combustion-supporting air shut-off valve; 7. Combustion-supporting air regulating valve; 8. Flue gas shut-off valve; 9. Hot blast furnace flue gas CO2 shut-off valve; 10. Hot blast furnace flue gas shut-off valve; 11. Blast furnace gas CO2 shut-off valve; 12. Buffer tank CO2 shut-off valve; 13. CO2 release valve; 14. Blind valve; 15. Ball valve; 16. Hot blast furnace flue gas shut-off valve; 17. Heating furnace flue gas shut-off valve;

[0028] 20, first pipeline; 21, second pipeline; 22, third pipeline; 23, air supply pipeline; 24, gas transmission pipeline; 25, fourth pipeline; 26, fifth pipeline; 27, sixth pipeline; 28, seventh pipeline; 29, eighth pipeline; 210, ninth pipeline; 211, tenth pipeline;

[0029] 30. Heating furnace; 31. Blast furnace; 32. Blast furnace flue gas CO2 separation and capture device; 33. Buffer tank; 34. Heat exchanger; 35. Hot blast furnace flue gas CO2 separation and capture device; 36. Chimney; 37. Blower; 38. Induced draft fan; 39. Gas pipeline network; 40. Hot blast furnace; 41. Gas pipeline network;

[0030] 50. Temperature measuring element; 51. Pressure measuring element. DETAILED DESCRIPTION

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] like Figure 1 As shown, a system for heating CO2 and inputting it into a blast furnace for smelting according to an embodiment of the present invention comprises a heating furnace 30, a blast furnace 31, a blast furnace flue gas CO2 separation and capture device 32, a buffer tank 33, a heat exchanger 34, a hot blast furnace flue gas CO2 separation and capture device 35 and a hot blast furnace 40;

[0033] The blast furnace flue gas generated by the blast furnace 31 can enter the blast furnace flue gas CO2 separation and capture device 32 for separation into CO2 and blast furnace gas. The CO2 gas separated by the blast furnace flue gas CO2 separation and capture device 32 can enter the buffer tank 33 for storage;

[0034] The high-temperature flue gas generated by the heating furnace 30 can enter the heat exchanger 34 to release heat;

[0035] The blast furnace flue gas generated by the hot blast furnace 40 can enter the hot blast furnace flue gas CO2 separation and capture device 35 for separation into CO2 and hot flue gas. The CO2 gas separated by the hot blast furnace flue gas CO2 separation and capture device 35 can enter the buffer tank 33 for storage;

[0036] The CO2 gas in the buffer tank 33 can enter the heat exchanger 34 to absorb heat for the first time;

[0037] The CO2 gas after the first heat absorption can enter the heating furnace 30 to absorb heat for the second time;

[0038] The CO2 gas after the second heat absorption can enter the blast furnace 31 to participate in smelting.

[0039] The flue gas outlet of the blast furnace 31 is connected to the inlet of the buffer tank 33 through the first pipeline 20. A blast furnace gas CO2 shut-off valve 11 is provided on the first pipeline 20. The blast furnace gas CO2 shut-off valve 11 is located between the blast furnace 31 and the buffer tank 33. The blast furnace flue gas CO2 separation and capture device 32 is located on the first pipeline 20. The blast furnace flue gas CO2 separation and capture device 32 can separate the blast furnace flue gas into CO2 and blast furnace gas. The blast furnace gas outlet of the blast furnace flue gas CO2 separation and capture device 32 is connected to the gas pipeline network 41 through the third pipeline 22. The blast furnace gas separated by the blast furnace flue gas CO2 separation and capture device 32 can enter the gas pipeline network 41 through the third pipeline 22.

[0040] like Figure 1As shown, the heating furnace 30 is connected to an air supply pipeline 23 and a gas delivery pipeline 24. Along the direction from the inlet end of the air supply pipeline 23 to the outlet end of the air supply pipeline 23, a combustion-supporting air regulating valve 7 and a combustion-supporting air shut-off valve 6 are sequentially arranged on the air supply pipeline 23. The inlet end of the air supply pipeline 23 is connected to a blower 37. Along the direction from the inlet end of the gas delivery pipeline 24 to the outlet end of the gas delivery pipeline 24, a gas regulating valve 4, a gas shut-off valve 3, a gas combustion valve 2 and a gas release valve 1 are sequentially arranged on the gas delivery pipeline 24. The inlet end of the gas delivery pipeline 24 is connected to the gas pipeline network 39.

[0041] The first flue gas outlet of the heating furnace 30 is connected to the heat release medium inlet of the heat exchanger 34 through the second pipe 21. The first flue gas outlet of the heating furnace 30 is externally connected to a temperature measuring element 50. The heat release medium outlet of the heat exchanger 34 is connected to the chimney 36 through the fourth pipe 25. The heat exchanger 34 contains a heat exchange medium, which can store heat (released by the high-temperature flue gas generated by the heating furnace 30 entering the heat exchanger 34).

[0042] The flue gas outlet of the hot blast stove 40 is connected to the inlet of the hot blast stove flue gas CO2 separation and capture device 35 through the fifth pipeline 26, and the hot blast stove flue gas CO2 separation and capture device 35 is provided with a hot blast stove flue gas cut-off valve 10. The hot blast stove flue gas CO2 separation and capture device 35 can separate the flue gas discharged from the hot blast stove 40 into CO2 and flue gas. The CO2 outlet of the hot blast stove flue gas CO2 separation and capture device 35 is connected to the inlet of the buffer tank 33 through the sixth pipeline 27, and the hot blast stove flue gas CO2 cut-off valve 9 and the induced draft fan 38 are provided on the sixth pipeline 27. The buffer tank 33 is connected to a pressure measuring element 51. The flue gas outlet of the hot blast stove flue gas CO2 separation and capture device 35 is connected to the chimney 36 through the seventh pipeline 28, and the seventh pipeline 28 is provided with a hot blast stove flue gas cut-off valve 16.

[0043] like Figure 1 As shown, the outlet of the buffer tank 33 is connected to the heat absorbing medium inlet of the heat exchanger 34 through the eighth pipeline 29, and the CO2 discharged from the buffer tank 33 can enter the heat exchanger 34 to absorb heat. The heat absorbing medium outlet of the heat exchanger 34 is connected to the heating furnace 30 through the ninth pipeline 210. The buffer tank CO2 shut-off valve 12, the CO2 release valve 13, the blind plate valve 14 and the ball valve 15 are sequentially arranged on the eighth pipeline 29. The heating furnace 30 is connected to the blast furnace 31 through the tenth pipeline 211, and the tenth pipeline 211 is provided with a CO2 shut-off valve 5.

[0044] The following is a method for heating CO2 and inputting it into a blast furnace for smelting. The method for heating CO2 and inputting it into a blast furnace for smelting adopts the above-mentioned system for heating CO2 and inputting it into a blast furnace for smelting. The method for heating CO2 and inputting it into a blast furnace for smelting comprises the following steps in sequence:

[0045] The blast furnace flue gas generated by the blast furnace 31 enters the blast furnace flue gas CO2 separation and capture device 32 and is separated into CO2 gas and blast furnace gas. The CO2 gas separated by the blast furnace flue gas CO2 separation and capture device 32 enters the buffer tank 33;

[0046] Air and gas enter the heating furnace 30 and burn to generate high-temperature flue gas which enters the heat exchanger 34 to release heat;

[0047] The blast furnace flue gas generated by the hot blast furnace 40 enters the hot blast furnace flue gas CO2 separation and capture device 35 and is separated into CO2 gas and flue gas. The CO2 gas separated by the hot blast furnace flue gas CO2 separation and capture device 35 enters the buffer tank 33;

[0048] The CO2 gas in the buffer tank 33 enters the heat exchanger 34 to absorb heat for the first time;

[0049] The CO2 gas after the first heat absorption enters the heating furnace 30, and the air and fuel gas enter the heating furnace 30 for combustion. The CO2 gas after the first heat absorption absorbs heat for the second time.

[0050] The CO2 gas after the second heat absorption enters the blast furnace 31 to participate in smelting.

[0051] Specifically, the flue gas outlet of the blast furnace 31 enters the blast furnace flue gas CO2 separation and capture device 32 through the first pipeline 20, and is separated into CO2 gas and blast furnace gas. The CO2 gas separated by the blast furnace flue gas CO2 separation and capture device 32 enters the buffer tank 33, and the separated blast furnace gas is sent to the gas network 41 through the third pipeline 22;

[0052] The combustion air shut-off valve 6 and the combustion air regulating valve 7 are opened, and the blower 37 blows air into the heating furnace 30. At the same time, the gas combustion valve 2, the gas shut-off valve 3 and the gas regulating valve 4 are opened, and gas is input into the heating furnace 30 through the gas pipeline network 39. The air and gas begin to burn in the heating furnace 30 and the flue gas shut-off valve 8 is opened. The high-temperature flue gas generated enters the heat exchanger 34 through the second pipeline 21, and the heat in the flue gas is stored in the heat exchanger 34 by heating the heat exchange unit (i.e., the heat exchange medium) in the heat exchanger 34. The flue gas after heat exchange is discharged through the chimney 36 through the fourth pipeline 25.

[0053] The hot blast furnace flue gas generated by the hot blast furnace 40 after heat exchange enters the hot blast furnace flue gas CO2 separation and capture device 35 through the fifth pipeline 26, and the separated CO2 is pressurized by the induced draft fan 38 and transported to the buffer tank 33 through the sixth pipeline 27, and the remaining high-temperature flue gas is discharged through the seventh pipeline 28 through the chimney 36.

[0054] The CO2 in the buffer tank 33 enters the heat exchanger 34 through the eighth pipeline 29 for primary preheating. The preheated CO2 enters the heating furnace 30 through the ninth pipeline 210 for secondary heating. After the CO2 gas is heated by the heating furnace 30 to reach the temperature required for blast furnace smelting, the CO2 shut-off valve 5 is opened, and the CO2 in the heating furnace 30 is input into the blast furnace 31 through the tenth pipeline 211 to participate in smelting.

[0055] When the pressure in the buffer tank 33 is greater than 0.5MPa, the blast furnace flue gas generated by the hot blast furnace 40 cannot enter the hot blast furnace flue gas CO2 separation and capture device 35, and the CO2 gas separated by the blast furnace flue gas CO2 separation and capture device 32 cannot enter the buffer tank 33; when the pressure in the buffer tank 33 is less than 0.4MPa, the blast furnace flue gas generated by the hot blast furnace 40 can enter the hot blast furnace flue gas CO2 separation and capture device 35, the CO2 gas separated by the hot blast furnace flue gas CO2 separation and capture device 35 can enter the buffer tank 33, and the CO2 gas separated by the blast furnace flue gas CO2 separation and capture device 32 can also enter the buffer tank 33.

[0056] Specifically, when the pressure in the buffer tank 33 is measured by the second pressure measuring element 51 to be greater than 0.5MPa, the hot blast furnace flue gas CO2 shut-off valve 9, the hot blast furnace flue gas shut-off valve 10, the blast furnace gas CO2 shut-off valve 11 and the induced draft fan 38 are closed; when the buffer tank pressure is less than 0.4MPa, the blast furnace flue gas CO2 shut-off valve 9, the hot blast furnace flue gas shut-off valve 10, the blast furnace gas CO2 shut-off valve 11 and the induced draft fan 38 are opened.

[0057] The buffer tank CO2 shut-off valve 12, the blind plate valve 14, the hot blast stove flue gas shut-off valve 16 and the heating furnace flue gas shut-off valve 17 are in a normally open state. When an emergency occurs and it is necessary to stop injecting CO2 into the blast furnace 31, the buffer tank CO2 shut-off valve 12 and the blind plate valve 14 are closed, and the CO2 release valve 13 is opened.

[0058] Specifically, under normal circumstances, the buffer tank CO2 shut-off valve 12, the blind plate valve 14, the hot blast furnace flue gas shut-off valve 16 and the heating furnace flue gas shut-off valve 17 are all in the normally open state. When an emergency occurs and it is necessary to stop injecting CO2 into the blast furnace 31, the buffer tank CO2 shut-off valve 12 and the blind plate valve 14 are closed, and the CO2 release valve 13 is opened.

[0059] When the flue gas temperature in the heating furnace 30 is greater than or equal to 300° C., the supply of fuel gas and air to the heating furnace 30 is stopped; when the flue gas temperature in the heating furnace 30 is lower than 250° C., fuel gas and air can be supplied to the heating furnace 30 .

[0060] Specifically, when the temperature of the flue gas in the heating furnace 30 reaches above 300°C as measured by the temperature measuring element 50, the combustion air shut-off valve 6 and the blower 37 are closed, and the gas combustion valve 2, the gas shut-off valve 3 and the gas regulating valve 4 are closed. When the temperature of the flue gas in the heating furnace 30 is lower than 250°C, the combustion air shut-off valve 6 and the blower 37 are opened, and the gas combustion valve 2, the gas shut-off valve 3 and the gas regulating valve 4 are opened.

[0061] The method of heating CO2 and inputting it into a blast furnace for smelting described in the present invention captures CO2 generated by blast furnace smelting and CO2 generated by hot blast furnace combustion, and feeds it into the blast furnace for smelting through a graded heating method, thereby promoting the indirect reduction reaction in the blast furnace and realizing the recycling of resources.

[0062] The source of CO2 consists of two parts. The first part is produced by blast furnace smelting. The blast furnace gas produced during the smelting process is separated from the blast furnace gas by the blast furnace gas CO2 separation and capture device, and then input into the buffer tank through the CO2 pipeline.

[0063] The second part is generated by the combustion of the hot blast furnace. According to the current process flow of the hot blast furnace, the hot blast furnace flue gas after heat exchange is discharged through the chimney. This scheme separates CO2 from the hot blast furnace flue gas after heat exchange through the hot blast furnace flue gas CO2 separation and capture device, and inputs it into the buffer tank through the CO2 pipeline.

[0064] The fan blows combustion-supporting air into the heating furnace, and the gas pipeline network inputs gas into the heating furnace. The air and gas burn in the heating furnace to produce high-temperature flue gas. The high-temperature flue gas is sent to the heat exchanger through the flue gas duct, and the heat it carries is stored in the heat exchanger. The flue gas from the heating furnace after heat exchange is input into the chimney through the flue gas duct for discharge.

[0065] The CO2 in the buffer tank is transported to the heat exchanger through the CO2 pipeline, and the heat stored in the flue gas of the heating furnace is used to achieve primary preheating to 180℃-250℃ (i.e. the temperature of CO2 after the first heat absorption is 180℃-250℃), and then it is input into the heating furnace through the CO2 gas pipeline for secondary preheating, heated to 1000℃-1250℃ (i.e. the temperature of CO2 after the second heat absorption is 180℃-250℃), and then it is input into the blast furnace through the CO2 pipeline to participate in smelting.

[0066] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the protection scope of the present invention should still fall within the scope of the present invention. In addition, the technical features of the present invention can be freely combined with each other, with technical features and technical solutions, with technical solutions and embodiments.

Claims

1. A system for heating CO2 and inputting it into a blast furnace for smelting, characterized in that: The system for heating CO2 and inputting it into a blast furnace for smelting comprises a heating furnace (30), a blast furnace (31), a blast furnace flue gas CO2 separation and capture device (32), a buffer tank (33), a heat exchanger (34), a hot blast furnace flue gas CO2 separation and capture device (35) and a hot blast furnace (40); The blast furnace flue gas generated by the blast furnace (31) can enter the blast furnace flue gas CO2 separation and capture device (32) for separation, and the CO2 gas separated by the blast furnace flue gas CO2 separation and capture device (32) can enter the buffer tank (33); The high-temperature flue gas generated by the heating furnace (30) can enter the heat exchanger (34) to release heat; The blast furnace flue gas generated by the hot blast furnace (40) can enter the hot blast furnace flue gas CO2 separation and capture device (35) for separation, and the CO2 gas separated by the hot blast furnace flue gas CO2 separation and capture device (35) can enter the buffer tank (33); The CO2 gas in the buffer tank (33) can enter the heat exchanger (34) to absorb heat for the first time; The CO2 gas after the first heat absorption can enter the heating furnace (30) to absorb heat for the second time; The CO2 gas after the second heat absorption can enter the blast furnace (31) to participate in smelting.

2. The system for heating CO2 and inputting it into a blast furnace for smelting according to claim 1 is characterized in that: The flue gas outlet of the blast furnace (31) is connected to the inlet of the buffer tank (33) through a first pipeline (20); the blast furnace flue gas CO2 separation and capture device (32) is located on the first pipeline (20); the blast furnace gas outlet of the blast furnace flue gas CO2 separation and capture device (32) is connected to the gas network (41) through a third pipeline (22); the blast furnace gas separated by the blast furnace flue gas CO2 separation and capture device (32) can enter the gas network (41) through the third pipeline (22).

3. The system for heating CO2 and inputting it into a blast furnace for smelting according to claim 1, characterized in that: The heating furnace (30) is connected to an air supply pipeline (23) and a gas delivery pipeline (24). A combustion-supporting air regulating valve (7) and a combustion-supporting air shut-off valve (6) are sequentially arranged on the air supply pipeline (23) along the direction from the inlet end of the air supply pipeline (23) to the outlet end of the air supply pipeline (23). A blower (37) is connected to the inlet end of the air supply pipeline (23). A gas regulating valve (4), a gas shut-off valve (3) and a gas combustion valve (2) are sequentially arranged on the gas delivery pipeline (24) along the direction from the inlet end of the gas delivery pipeline (24) to the outlet end of the gas delivery pipeline (24). The inlet end of the gas delivery pipeline (24) is connected to a gas pipeline network (39).

4. The system for heating CO2 and inputting it into a blast furnace for smelting according to claim 1, characterized in that: The first smoke outlet of the heating furnace (30) is connected to the heat release medium inlet of the heat exchanger (34) through the second pipe (21), the first smoke outlet of the heating furnace (30) is externally connected to a temperature measuring element (50), the heat release medium outlet of the heat exchanger (34) is connected to the chimney (36) through the fourth pipe (25), and the heat exchanger (34) contains a heat exchange medium, which can store heat.

5. The system for heating CO2 and inputting it into a blast furnace for smelting according to claim 1, characterized in that: The flue gas outlet of the hot blast furnace (40) is connected to the inlet of the hot blast furnace flue gas CO2 separation and capture device (35) through a fifth pipeline (26); the CO2 outlet of the hot blast furnace flue gas CO2 separation and capture device (35) is connected to the inlet of the buffer tank (33) through a sixth pipeline (27); a hot blast furnace flue gas CO2 shut-off valve (9) and an induced draft fan (38) are provided on the sixth pipeline (27); a pressure measuring element (51) is connected to the buffer tank (33); and the flue gas outlet of the hot blast furnace flue gas CO2 separation and capture device (35) is connected to the chimney (36) through a seventh pipeline (28).

6. The system for heating CO2 and inputting it into a blast furnace for smelting according to claim 1, characterized in that: The outlet of the buffer tank (33) is connected to the heat absorbing medium inlet of the heat exchanger (34) through an eighth pipeline (29), and the heat absorbing medium outlet of the heat exchanger (34) is connected to the heating furnace (30) through a ninth pipeline (210). The eighth pipeline (29) is provided with a buffer tank CO2 cut-off valve (12), a CO2 release valve (13), a blind plate valve (14) and a ball valve (15) in sequence. The heating furnace (30) is connected to the blast furnace (31) through a tenth pipeline (211).

7. A method for heating CO2 and inputting it into a blast furnace for smelting, characterized in that: The method of heating CO2 and inputting it into a blast furnace for smelting adopts the system of heating CO2 and inputting it into a blast furnace for smelting as claimed in claim 1, and the method of heating CO2 and inputting it into a blast furnace for smelting comprises the following steps in sequence: The blast furnace flue gas generated by the blast furnace (31) enters the blast furnace flue gas CO2 separation and capture device (32) for separation, and the CO2 gas separated by the blast furnace flue gas CO2 separation and capture device (32) enters the buffer tank (33); Air and gas enter the heating furnace (30) and burn to generate high-temperature flue gas which enters the heat exchanger (34) to release heat; The blast furnace flue gas generated by the hot blast furnace (40) enters the hot blast furnace flue gas CO2 separation and capture device (35) for separation, and the CO2 gas separated by the hot blast furnace flue gas CO2 separation and capture device (35) enters the buffer tank (33); The CO2 gas in the buffer tank (33) enters the heat exchanger (34) to absorb heat for the first time; The CO2 gas after the first heat absorption enters the heating furnace (30), air and fuel gas enter the heating furnace (30) and burn, and the CO2 gas after the first heat absorption absorbs heat for the second time; The CO2 gas after the second heat absorption enters the blast furnace (31) to participate in smelting.

8. The method of heating CO2 and inputting it into a blast furnace for smelting according to claim 7, characterized in that: When the pressure in the buffer tank (33) is greater than 0.5 MPa, the blast furnace flue gas generated by the hot blast furnace (40) cannot enter the hot blast furnace flue gas CO2 separation and capture device (35), and the CO2 gas separated by the blast furnace flue gas CO2 separation and capture device (32) cannot enter the buffer tank (33); When the pressure in the buffer tank (33) is less than 0.4 MPa, the blast furnace flue gas generated by the hot blast furnace (40) can enter the hot blast furnace flue gas CO2 separation and capture device (35), the CO2 gas separated by the hot blast furnace flue gas CO2 separation and capture device (35) can enter the buffer tank (33), and the CO2 gas separated by the blast furnace flue gas CO2 separation and capture device (32) can also enter the buffer tank (33).

9. The method of heating CO2 and inputting it into a blast furnace for smelting according to claim 7, characterized in that: The buffer tank CO2 shut-off valve (12), the blind plate valve (14), the hot blast furnace flue gas shut-off valve (16) and the heating furnace flue gas shut-off valve (17) are in a normally open state. When an emergency situation occurs and it is necessary to stop injecting CO2 into the blast furnace (31), the buffer tank CO2 shut-off valve (12) and the blind plate valve (14) are closed, and the CO2 release valve (13) is opened.

10. The method of heating CO2 and inputting it into a blast furnace for smelting according to claim 7, characterized in that: When the flue gas temperature in the heating furnace (30) is greater than or equal to 300° C., the supply of fuel gas and air to the heating furnace (30) is stopped; when the flue gas temperature in the heating furnace (30) is lower than 250° C., fuel gas and air can be supplied to the heating furnace (30).

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