Method for switching hydrogen-rich carbon circulating oxygen blast furnace process and traditional blast furnace process

Abstract

The invention belongs to the technical field of blast furnace smelting, and particularly discloses a method for mutually switching a hydrogen-rich carbon circulating oxygen blast furnace process and a traditional blast furnace process, which comprises the following steps: firstly, closing a decarburization system of a hydrogen-rich carbon circulating oxygen blast furnace, then closing a purified gas cut-off device at the top of an absorption tower and a communicating device at the outlet of a flash tank, and then a combustion-supporting air valve is opened, then nitrogen is used for conducting purging replacement on the gas pipeline and the gas heating furnace, and then the hydrogen-rich carbon circulating oxygen blast furnace can be switched into the traditional blast furnace process. In order to solve the problem that when a hydrogen-rich carbon cycle oxygen blast furnace is used for production in winter, the decarburization energy efficiency of the hydrogen-rich carbon cycle oxygen blast furnace is reduced due to the low temperature, and consequently pipe network gas is unbalanced, the hydrogen-rich carbon cycle oxygen blast furnace technology is switched into a traditional blast furnace mode; the problem that due to the low temperature in winter in the north, the decarburization energy efficiency of the hydrogen-rich carbon circulating oxygen blast furnace is reduced, and consequently pipe network gas is unbalanced is solved.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace smelting, and in particular to a method for switching between a hydrogen-rich carbon cycle oxygen blast furnace process and a traditional blast furnace process. Background Art

[0002] The hydrogen-rich carbon circulating oxygen blast furnace is a smelting process that uses cold oxygen blast to replace traditional heated air blast. It uses full oxygen blast, CO2 removal from the top gas, and circulating injection of reduced gas after heating to remove CO2 to improve the chemical energy utilization rate of blast furnace carbon. In the north, due to the recycling of the top gas of the hydrogen-rich carbon circulating oxygen blast furnace, the gas entering the pipeline network is sharply reduced, resulting in an imbalance of gas in northern steel plants in winter. It is necessary to switch the hydrogen-rich carbon circulating oxygen blast furnace process to the traditional blast furnace process. At the same time, the top gas of the hydrogen-rich carbon circulating oxygen blast furnace contains 28%-35% of CO2 acidic gas. The CO2 in the top gas is removed by the decarbonization device. When the decarbonization system cannot meet production needs or fails, it is necessary to switch the hydrogen-rich carbon circulating oxygen blast furnace process to the traditional blast furnace process.

[0003] In the existing technology, due to the difference in process, the core technology is to replace heating gas in the gas heating furnace with heating air, and at the same time, the decarbonization system needs to be put into and withdrawn, so there are safety risks such as gas explosion during the switching process. Therefore, it is necessary to design a method for switching between the hydrogen-rich carbon cycle oxygen blast furnace process and the traditional blast furnace process, which can safely complete the switching between the hydrogen-rich carbon cycle oxygen blast furnace and the traditional blast furnace, so as to solve the problem of unbalanced gas in the pipeline network caused by the low temperature during winter production, which causes the decarbonization energy efficiency of the hydrogen-rich carbon cycle oxygen blast furnace to decrease. Summary of the invention

[0004] The purpose of the present invention is to provide a method for switching between a hydrogen-rich carbon cycle oxygen blast furnace process and a conventional blast furnace process to solve the problem of 2500m 3 The decarbonization efficiency of large hydrogen-rich carbon circulating oxygen blast furnaces has been reduced, leading to an imbalance in the gas pipeline network.

[0005] To achieve the above object, the basic scheme provided by the present invention is: a method for switching between a hydrogen-rich carbon cycle oxygen blast furnace process and a traditional blast furnace process, comprising the following steps:

[0006] S1: When it is necessary to switch the hydrogen-rich carbon cycle oxygen blast furnace process to the traditional blast furnace process for production, first close the blind plate valve at the inlet of the decarbonization and fine dust removal device of the hydrogen-rich carbon cycle oxygen blast furnace;

[0007] S2: Then close the purified gas cut-off device at the top of the absorption tower;

[0008] S3: Then the staff closes the connecting device at the top outlet of the flash tank, and then opens the combustion air valve;

[0009] S4: Then open the nitrogen purge valve and purge the switched gas pipeline and hot air furnace with nitrogen for 2-3 hours, so that the gas inside the hot air furnace and the pipeline can be replaced to meet the requirements;

[0010] S5: After switching to the traditional blast furnace process, the gas from the top of the traditional blast furnace is reduced in pressure through the dust collector and the four-valve group, and then enters the hot blast furnace and other users through the gas pipeline network.

[0011] The beneficial effect of the present invention is that during winter production, the hydrogen-rich carbon circulating oxygen blast furnace process is switched to the traditional blast furnace process, thereby solving the problem of reduced decarbonization efficiency of the hydrogen-rich carbon circulating oxygen blast furnace due to low winter temperatures, resulting in unbalanced gas in the pipeline network. During summer production, it can be switched again to the hydrogen-rich carbon circulating oxygen blast furnace for production.

[0012] Option 2 is the preferred basic option. In S1, when switching, the hydrogen-rich carbon circulating oxygen blast furnace is in a dormant state, and the dormant state lasts for 8-10 hours.

[0013] Scheme 3, which is the preferred basic scheme, in S5, after switching to the traditional blast furnace process, the contents of the top gas are: CO: 23-26%; CO2: 18.5%-23%; N2: 53%-57%; H 2： 1.5%-3%; the mass percentage of molten iron components is Si≤0.45%; Ti≤0.2%; S≤0.05%; the binary basicity of slag is controlled at R2=1.05 times-1.18 times.

[0014] Scheme 4 is the preferred basic scheme. In S5, 30%-40% of the decompressed top gas enters the hot blast furnace to heat the air. The temperature of the hot blast furnace to heat the air is 800°C-1200°C.

[0015] Scheme 5, a method for switching a conventional blast furnace process to a hydrogen-rich carbon cycle oxygen blast furnace process, characterized in that it comprises the following steps:

[0016] A: When it is necessary to switch the traditional blast furnace process to the hydrogen-rich carbon circulating oxygen blast furnace process for production, first open the blind plate valve at the fine dust removal inlet of the decarbonization system;

[0017] B: Then open the purified gas cut-off device at the top of the absorption tower, then open the connecting device at the top outlet of the flash tank, and then close the combustion air valve;

[0018] C: Open the nitrogen purge valve and purge the switched gas pipeline and gas heating furnace with nitrogen for 2-3 hours to replace the gas in the hot air furnace and pipeline to meet the requirements;

[0019] D: After switching to the hydrogen-rich carbon cycle oxygen blast furnace process, the open air supply method of oxygen-nitrogen mixture is adopted. After the coal gas is generated, the top coal gas passes through the dust collector, one way is reduced by the four-valve group, and then passes through the gas pipe network to enter the hot blast furnace or other users for use, and the other way enters the decarbonization fine dust removal device to further purify the coal gas impurities to 0.5mg / Nm 3 -2mg / Nm 3 After being pressurized to 1.3MPa-1.8MPa by a compressor, it enters from the bottom of the absorption tower, contacts with the alcoholamine solution in the absorption tower, and captures the CO2 in the hydrogen-rich carbon cycle oxygen blast furnace gas. The purified gas is discharged from the top of the absorption tower and enters the hot blast furnace through a pipeline for heating;

[0020] E: The alcohol amine rich liquid that has absorbed CO2 in the absorption tower enters the flash tank to flash out some CO2 and CO gas, which is connected to the gas network through the connecting device on the top of the flash tank and mixed. After decompression, it passes through the gas network and enters the hot air furnace or other users for use;

[0021] F: The rich alcoholamine liquid in the flash tank enters the regeneration tower from the bottom to further remove CO2. The CO2 in the rich alcoholamine liquid is regenerated in the upper part of the regeneration tower to be partially resolved and discharged from the top of the regeneration tower. The alcoholamine solution after CO2 regeneration enters the reboiler and is heated to 63℃-79℃, and then enters the lower part of the regeneration tower again for regeneration and resolution. The CO2 regenerated in the upper and lower parts of the regeneration tower enters the gas-liquid separator through the top of the regeneration tower, and the separated CO2 is liquefied through the liquefaction device, and the separated solution is refluxed to the top of the regeneration tower for use.

[0022] Option 6, which is the preferred option of the basic option, in D, the content of CO2 in the purified gas is 0.5%-3%.

[0023] Option seven, which is the preferred basic option, in D, the purified gas is heated to 800°C-1250°C in a hot blast furnace and then sprayed into the blast furnace.

[0024] Scheme 8: This is the preferred basic scheme. In D, the pressure of the purified gas is 1MPa-1.6MPa, and the calorific value of the purified gas after CO2 removal is 8500kJ / Nm 3 -9200kJ / Nm 3 .

[0025] Scheme 9, which is the preferred basic scheme, in E, the calorific value of the top gas of the hydrogen-rich carbon circulating oxygen blast furnace is 6500kJ / Nm 3 -7100kJ / Nm 3 The calorific value after mixing with the CO2 and CO gas flashed out of the flash tank is 3000kJ / Nm 3 -3500kJ / Nm3 ; It has reached the conventional calorific value that can be used by pipeline network users, making it easy to put into use. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process flow diagram of a method for switching between a large-scale hydrogen-rich carbon cycle oxygen blast furnace process and a traditional blast furnace process according to the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below through specific embodiments:

[0028] The figure marks in the drawings of the specification include: 1. Hydrogen-rich carbon circulating oxygen blast furnace; 2. Dust collector; 3. Decarbonization and fine dust removal device; 4. Four-valve group; 5. Blind plate valve; 6. Hot blast furnace; 7. Pressurizer; 8. Absorption tower; 9. Flash tank; 10. Interconnecting device; 11. Regeneration tower; 12. Liquefaction device; 13. Reboiler; 14. Gas-liquid separator; 15. Gas pipeline network; 16. Purified gas cut-off device; 17. Combustion air valve; 18. Nitrogen purge valve.

[0029] Example 1

[0030] like Figure 1 As shown, a method for switching a hydrogen-rich carbon cycle oxygen blast furnace process to a conventional blast furnace process comprises the following steps:

[0031] S1: When it is necessary to switch the hydrogen-rich carbon cycle oxygen blast furnace process to the conventional blast furnace process for production, first close the blind plate valve 5 at the inlet of the decarbonization fine dust removal device 3 of the hydrogen-rich carbon cycle oxygen blast furnace 1;

[0032] S2: Then close the purified gas cut-off device 16 at the top of the absorption tower 8;

[0033] S3: Then the staff closes the connecting device 10 at the top outlet of the flash tank 9, and then opens the combustion air valve 17;

[0034] S4: Then open the nitrogen purge valve 18, and purge the switched gas pipeline and the hot blast furnace 6 with nitrogen for 2-3 hours, so that the gas inside the hot blast furnace 6 and the pipeline can be replaced to meet the requirements;

[0035] S5: After switching to the conventional blast furnace process, the gas from the top of the conventional blast furnace is decompressed by the dust collector 2 and the four-valve group 4 and then enters the hot blast furnace 6 and other users through the gas pipe network 15; 30%-40% of the top gas after decompression enters the hot blast furnace 6 for heating air, and the hot blast furnace 6 heats the air to 800°C-1200°C and then passes it into the blast furnace; the contents of the top gas after switching to the conventional blast furnace process are: CO: 23-26%; CO2: 18.5%-23%; N2: 53%-57%; H 2：1.5%-3%; the mass percentage of molten iron composition is Si≤0.45%; Ti≤0.2%; S≤0.05%; the binary basicity of slag is controlled at R2=1.05 times-1.18 times;

[0036] Through the above method, the hydrogen-rich carbon circulating oxygen blast furnace process is switched to the traditional blast furnace process during winter production, which solves the problem of unbalanced gas in the pipeline network caused by the reduced decarbonization efficiency of the hydrogen-rich carbon circulating oxygen blast furnace due to the low temperature in northern winter.

[0037] Example 2

[0038] like Figure 1 As shown, a method for switching a traditional blast furnace process to a hydrogen-rich carbon cycle oxygen blast furnace process is characterized by comprising the following steps:

[0039] A: When it is necessary to switch the conventional blast furnace process to the hydrogen-rich carbon circulating oxygen blast furnace process for production, first open the blind plate valve 5 at the inlet of the decarbonization fine dust removal device 3;

[0040] B: Then open the purified gas cut-off device 16 at the top of the absorption tower 8, then open the connecting device 10 at the top outlet of the flash tank 9, and then close the combustion air valve 17;

[0041] C: Open the nitrogen purge valve 18, and purge the switched gas pipeline and gas heating furnace with nitrogen for 2-3 hours, so that the gas inside the hot blast furnace 6 and the pipeline can be replaced to meet the requirements;

[0042] D: After switching to the hydrogen-rich carbon cycle oxygen blast furnace process, the open air supply method of oxygen-nitrogen mixture is adopted. After the coal gas is generated, the top coal gas passes through the dust collector 2, one way is reduced by the four-valve group 4, and then passes through the gas pipe network 15 to enter the hot blast furnace 6 or other users for use, and the other way enters the decarbonization fine dust removal device 3 to further purify the coal gas impurities to 0.5mg / Nm 3 -2mg / Nm 3 After being pressurized to 1.3MPa-1.8MPa by the compressor 7, it enters from the bottom of the absorption tower 8, contacts with the alcohol amine solution in the absorption tower 8, and captures the CO2 in the hydrogen-rich carbon cycle oxygen blast furnace 1 gas. The purified gas is discharged from the top of the absorption tower 8. The pressure of the purified gas is 1MPa-1.6MPa, and the content of CO2 in the purified gas is 0.5%-3%. The calorific value of the purified gas after removing CO2 is 8500kJ / Nm 3 -9200kJ / Nm 3 , enters the hot blast furnace 6 through the pipeline for heating, and is sprayed into the blast furnace after being heated to 800℃-1250℃;

[0043] E: The alcohol amine rich liquid that has absorbed CO2 in the absorption tower 8 enters the flash tank 9 to flash out some CO2 and CO gas, which is connected to the gas network 15 through the connecting device 10 on the top of the flash tank 9 and mixed. The calorific value of the mixed furnace top gas is 3000kJ / Nm 3 -3500kJ / Nm 3 , after being decompressed, it passes through the gas pipe network 15 and enters the hot air furnace 6 or other users for use;

[0044] F: The alcohol amine rich liquid in the flash tank 9 enters the regeneration tower 11 from the bottom to further remove CO2. The CO2 in the alcohol amine rich liquid is regenerated in the upper part of the regeneration tower 11 to partially resolve and is discharged from the top of the regeneration tower 11. The alcohol amine solution after CO2 regeneration enters the reboiler 13 and is heated to 63°C-79°C, and then enters the lower part of the regeneration tower 11 again for regeneration and resolution. The CO2 regenerated in the upper and lower parts of the regeneration tower 11 enters the gas-liquid separator 14 through the top of the regeneration tower, and the separated CO2 is liquefied by the liquefaction device 12, and the separated solution is refluxed to the top of the regeneration tower 11.

[0045] Through the above method, during summer production, it is possible to switch again to the hydrogen-rich carbon circulating oxygen blast furnace process for production, using full oxygen blasting, top gas to remove CO2, and reduced gas circulating injection technology after heating to remove CO2, thereby improving the chemical energy utilization rate of carbon in the blast furnace.

[0046] In summary, the present invention achieves the safe switching between the hydrogen-rich carbon circulating oxygen blast furnace process and the traditional blast furnace process, and solves the problem of unbalanced coal gas in the pipeline network caused by the reduced decarbonization efficiency of the hydrogen-rich carbon circulating oxygen blast furnace during production due to the low temperature in northern winter.

[0047] 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 switching a hydrogen-rich carbon cycle oxygen blast furnace process to a conventional blast furnace process, characterized in that: The following steps are involved: S1: When it is necessary to switch the hydrogen-rich carbon cycle oxygen blast furnace process to the conventional blast furnace process for production, first close the blind plate valve (5) at the inlet of the decarbonization fine dust removal device (3) of the hydrogen-rich carbon cycle oxygen blast furnace (1); S2: Then close the purified gas cut-off device (16) at the top of the absorption tower (8); S3: The staff then closes the connecting device (10) at the top outlet of the flash tank (9), and then opens the combustion air valve (17); S4: Then open the nitrogen purge valve (18) and purge the switched gas pipeline and the hot air furnace (6) with nitrogen for 2-3 hours, so that the gas in the hot air furnace (6) and the pipeline can be replaced to meet the requirements; S5: After switching to the conventional blast furnace process, the coal gas at the top of the conventional blast furnace is reduced in pressure by passing through the dust collector (2) and the four-valve group (4) and then enters the hot blast furnace (6) through the gas pipeline network (15) and is used by other users.

2. The method for switching a hydrogen-rich carbon cycle oxygen blast furnace process to a conventional blast furnace process according to claim 1, characterized in that: In S1, when switching, the hydrogen-rich carbon circulating oxygen blast furnace (1) is in a dormant state, and the dormant state lasts for 8-10 hours.

3. The method for switching a hydrogen-rich carbon cycle oxygen blast furnace process to a conventional blast furnace process according to claim 1, characterized in that: In S5, after switching to the conventional blast furnace process, the contents of the top gas are: CO: 23-26%; CO2: 18.5%-23%; N2: 53%-57%; H 2： 1.5%-3%; the mass percentage of molten iron components is Si≤0.45%; Ti≤0.2%; S≤0.05%; the binary basicity of slag is controlled at R2=1.05 times-1.18 times.

4. The method for switching a hydrogen-rich carbon cycle oxygen blast furnace process to a conventional blast furnace process according to claim 1, characterized in that: In S5, 30%-40% of the decompressed top gas enters the hot blast furnace (6) to heat the air. The temperature of the air heated by the hot blast furnace (6) is 800°C-1200°C.

5. A method for switching a conventional blast furnace process to a hydrogen-rich carbon cycle oxygen blast furnace process, characterized in that: The following steps are involved: A: When it is necessary to switch the conventional blast furnace process to the hydrogen-rich carbon circulating oxygen blast furnace process for production, first open the blind plate valve (5) at the inlet of the decarbonization fine dust removal device (3); B: Then open the purified gas cut-off device (16) at the top of the absorption tower (8), then open the connecting device (10) at the top outlet of the flash tank (9), and then close the combustion air valve (17); C: Open the nitrogen purge valve (18) and purge the switched gas pipeline and the hot air furnace (6) with nitrogen for 2-3 hours, so that the gas in the hot air furnace (6) and the pipeline can be replaced to meet the requirements; D: After switching to the hydrogen-rich carbon cycle oxygen blast furnace process, the open air supply method of oxygen-nitrogen mixture is adopted. After the coal gas is generated, the top coal gas passes through the dust collector (2), one way passes through the four-valve group (4) to reduce the pressure, and then passes through the coal gas pipeline (15) to enter the hot blast furnace (6) or other users for use, and the other way enters the decarbonization fine dust removal device (3) to further purify the coal gas impurities to 0.5mg / Nm 3 -2mg / Nm 3 , after being pressurized to 1.3MPa-1.8MPa by a compressor (7), the gas enters from the bottom of an absorption tower (8), contacts with the alcohol amine solution in the absorption tower (8), and then captures CO2 in the gas of a hydrogen-rich carbon cycle oxygen blast furnace (1). The purified gas is discharged from the top of the absorption tower (8) and enters a hot blast furnace (6) through a pipeline for heating; E: The alcohol amine-rich liquid that has absorbed CO2 in the absorption tower (8) enters the flash tank (9) to flash off part of the CO2 and CO gas, and is connected to the gas network (15) through the connecting device (10) on the top of the flash tank (9) and mixed. After decompression, it passes through the gas network (15) and enters the hot air furnace (6) or other users for use; F: The alcohol amine rich liquid in the flash tank (9) enters the regeneration tower (11) from the bottom to further remove CO2. The CO2 in the alcohol amine rich liquid is regenerated in the upper part of the regeneration tower (11) to be partially resolved and discharged from the top of the regeneration tower (11). The alcohol amine solution after CO2 regeneration enters the reboiler (13) and is heated to 63°C-79°C. It then enters the lower part of the regeneration tower (11) again for regeneration and resolution. The CO2 regenerated in the upper and lower parts of the regeneration tower (11) enters the gas-liquid separator (14) through the top of the regeneration tower. The separated CO2 is liquefied by the liquefaction device (12), and the separated solution is refluxed to the top of the regeneration tower (11).

6. The method for switching a conventional blast furnace process to a hydrogen-rich carbon cycle oxygen blast furnace process according to claim 5, characterized in that: In D, the CO2 content in the purified gas is 0.5%-3%.

7. The method for switching a conventional blast furnace process to a hydrogen-rich carbon cycle oxygen blast furnace process according to claim 5, characterized in that: In D, the purified gas is heated to 800°C-1250°C in a hot blast furnace (6) and then sprayed into the blast furnace.

8. The method for switching a conventional blast furnace process to a hydrogen-rich carbon cycle oxygen blast furnace process according to claim 5, characterized in that: In D, the pressure of the purified gas is 1MPa-1.6MPa, and the calorific value of the purified gas after removing CO2 is 8500kJ / Nm 3 -9200kJ / Nm 3 .

9. The method for switching a conventional blast furnace process to a hydrogen-rich carbon cycle oxygen blast furnace process according to claim 5, characterized in that: In E, the calorific value of the top gas of the hydrogen-rich carbon cycle oxygen blast furnace (1) is 6500 kJ / Nm 3 -7100kJ / Nm 3 The calorific value after mixing with the CO2 and CO gas flashed out of the flash tank (9) is 3000 kJ / Nm 3 -3500kJ / Nm 3 .

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