A steel plant secondary energy recycling and hydrogen metallurgical method, system and application thereof

Abstract

This invention discloses a method, system, and application for secondary energy recovery and utilization in steel plants and hydrogen metallurgy. The method includes: obtaining by-product coal gas from the steel plant, separating reducing gases, and introducing them into a hydrogen-based shaft furnace to produce sponge iron; the reducing gases include a first decarburization gas, a second decarburization gas, a third decarburization and denitrification gas, and hydrogen, or, include the first decarburization gas, the third decarburization and denitrification gas, and hydrogen; the first decarburization gas is obtained by decarburizing FINEX coal gas, the second decarburization gas is obtained by decarburizing converter gas, the third decarburization and denitrification gas is obtained by decarburizing and denitrifying the top coal gas of the hydrogen-based shaft furnace, and the hydrogen is obtained by hydrogen extraction from coke oven gas; the coke oven gas is further hydrogenated to obtain a fourth desorbed gas, which is injected into the blast furnace for low-carbon smelting to produce molten iron. This invention is of great significance for utilizing secondary energy from steel plants, reducing primary energy consumption in hydrogen-based shaft furnaces, and reducing carbon emissions from blast furnaces.

Description

Technical Field

[0001] This invention relates to the field of hydrogen metallurgy technology, and in particular to a method, system and application of secondary energy recovery and utilization in steel plants and hydrogen metallurgy. Background Technology

[0002] Hydrogen metallurgy reduces carbon emissions by replacing carbon with hydrogen during ore reduction. The main hydrogen metallurgical processes include hydrogen-rich blast furnaces and hydrogen-based shaft furnaces. Hydrogen-rich blast furnaces use hydrogen-rich gas injected through the blast furnace tuyeres to replace part of the CO reduction process, thus reducing carbon emissions. Existing hydrogen-based shaft furnaces primarily use natural gas catalytic reforming for their reducing gas (H2 and CO). The Zhongjin Taihang CSDRI shaft furnace in China uses coke oven gas reforming for its reducing gas, both requiring additional reformers and catalysts. Zhangxuan High-Tech's shaft furnace utilizes in-furnace zero-reforming of coke oven gas, requiring higher temperatures and pressures, thus placing higher demands on the furnace.

[0003] Steel mills generate large quantities of by-product gases annually, including coke oven gas and converter gas. Coke oven gas contains over 50% H2 and 20% CH4, making it suitable as injection gas for hydrogen metallurgy. Converter gas contains over 50% CO, serving as supplementary gas for hydrogen metallurgy to compensate for the heat consumed in H2 reduction and enhance the carburization of sponge iron. FINEX, a non-blast furnace smelting reduction process, has been successfully applied in South Korea. FINEX gas contains CO and H2 (over 60%), and due to its oxygen-enriched operation, its N2 content is extremely low, allowing it to be used as supplementary gas for hydrogen metallurgical reduction after decarburization.

[0004] If the reducing gases from coke oven gas, converter gas, and Finex gas can be used in hydrogen-based shaft furnace smelting, it would not only recover and utilize a large amount of secondary energy generated by steel plants (especially those with Finex units), but also reduce the equipment investment required for the conversion and reforming stages needed to produce reducing gases, thus simplifying the hydrogen-based shaft furnace process. Furthermore, if methane from coke oven gas could be injected into the blast furnace for smelting, the fuel ratio of the blast furnace could be reduced, thus decreasing carbon emissions.

[0005] Therefore, it is necessary to develop a method and system for the recovery and utilization of secondary energy in steel plants and hydrogen metallurgy, so as to provide important technical support for the recovery of secondary energy in steel plants, the reduction of primary energy consumption in hydrogen-based shaft furnaces, and the reduction of carbon emissions in the ironmaking process. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for secondary energy recovery and utilization in steel plants and hydrogen metallurgy, which reduces the equipment investment required for the conversion and reforming process to prepare reducing gases, reduces carbon emissions from hydrogen-based shaft furnaces and hydrogen-rich blast furnaces, and also provides a hydrogen metallurgy system that is non-conversion, highly efficient in reduction, and carburizing.

[0007] To achieve the above and other related objectives, the first aspect of the present invention provides a method for secondary energy recovery and utilization in steel plants and hydrogen metallurgy, comprising:

[0008] Obtain by-product coal gas from steel plants, separate the reducing gas, and introduce it into a hydrogen-based vertical shaft furnace to produce sponge iron. The top coal gas discharged from the top of the hydrogen-based vertical shaft furnace is recycled.

[0009] The by-product gas from the steel plant includes FINEX gas, converter gas, hydrogen-based vertical shaft furnace top gas, and coke oven gas.

[0010] The reducing gas includes a first decarbonization gas, a second decarbonization gas, a third decarbonization and denitrification gas, and hydrogen; or, the reducing gas includes a first decarbonization gas, a third decarbonization and denitrification gas, and hydrogen.

[0011] The first decarbonized gas is obtained by separating the FINEX gas through decarbonization treatment; the second decarbonized gas is obtained by separating the converter gas through decarbonization treatment; the third decarbonized and denitrified gas is obtained by separating the hydrogen-based vertical shaft furnace top gas through decarbonization and denitrification treatment; and the hydrogen is obtained by separating the coke oven gas through hydrogen extraction treatment.

[0012] The coke oven gas is subjected to hydrogen extraction treatment to separate hydrogen and a fourth desorbed gas. The fourth desorbed gas is injected into the blast furnace for low-carbon smelting to produce molten iron. Further, the FINEX gas is subjected to decarbonization separation to obtain a first decarbonized gas and a first desorbed gas. The first desorbed gas is transported to the steelmaking workshop for CO2 steelmaking.

[0013] Furthermore, the converter gas is decarbonized to obtain the second decarbonized gas and the second desorbed gas, and the second desorbed gas is transported to the steel plant's gas pipeline network.

[0014] Furthermore, the method further includes: separating a portion of the hydrogen-based vertical furnace top gas through decarbonization and denitrification to obtain the third decarbonized and denitrified gas, and using another portion of the hydrogen-based vertical furnace top gas as the first fuel gas to heat the reducing gas; preferably, the volume fraction of the other portion of the hydrogen-based vertical furnace top gas used as the first fuel gas is 3.5 to 30.5%.

[0015] Furthermore, a portion of the hydrogen-based vertical furnace top gas is decarbonized and denitrified to obtain the third decarbonized and denitrified gas and the third desorbed gas. A portion of the third desorbed gas is used as a second fuel gas to heat the reducing gas.

[0016] Furthermore, another portion of the third desorbed gas is delivered to the steel plant's gas pipeline network.

[0017] Furthermore, the volume ratio of the first fuel gas to the second fuel gas is ≥3.

[0018] Furthermore, the converter gas underwent purification treatment before being decarbonized.

[0019] Furthermore, the coke oven gas underwent purification treatment before hydrogen extraction.

[0020] Furthermore, the FINEX gas undergoes dust removal treatment before decarbonization; preferably, the dust removal treatment of the FINEX gas includes coarse dust removal and wet dust removal; more preferably, the dust content of the FINEX gas after coarse dust removal is ≤6g / Nm³. 3 The dust content of FINEX gas after wet dust removal is ≤5mg / Nm³. 3 .

[0021] Furthermore, the hydrogen-based vertical shaft furnace top gas undergoes dust removal treatment before being decarbonized and denitrified, and before being used as the primary fuel gas; preferably, the dust removal treatment of the hydrogen-based vertical shaft furnace top gas includes coarse dust removal and dry dust removal; more preferably, the dust content of the hydrogen-based vertical shaft furnace top gas after coarse dust removal is ≤6g / Nm³. 3 The dust content of the top gas from the hydrogen-based vertical shaft furnace after dry dust removal is ≤5mg / Nm³. 3 .

[0022] Furthermore, the FINEX gas is pressurized before decarbonization; preferably, the pressurized FINEX gas has a pressure of 0.45 to 0.55 MPa, and the pressure of the first decarbonized gas obtained after decarbonization at this pressure is 0.4 to 0.5 MPa.

[0023] Furthermore, the converter gas is pressurized before decarbonization; preferably, the pressurized converter gas has a pressure of 0.45 to 0.55 MPa, and the pressure of the second decarbonized gas obtained after decarbonization at this pressure is 0.4 to 0.5 MPa.

[0024] Furthermore, the hydrogen-based vertical furnace top gas is pressurized before undergoing decarbonization and denitrification treatment; preferably, the pressurized hydrogen-based vertical furnace top gas has a pressure of 0.45 to 0.55 MPa, and the pressure of the third decarbonized and denitrified gas obtained by separating the hydrogen-based vertical furnace top gas after decarbonization and denitrification treatment at this pressure is 0.4 to 0.5 MPa.

[0025] Furthermore, the coke oven gas is pressurized before hydrogen extraction; preferably, the pressurized coke oven gas has a pressure of 0.45 to 0.55 MPa, and the hydrogen obtained by hydrogen extraction from the coke oven gas at this pressure has a pressure of 0.4 to 0.5 MPa.

[0026] Furthermore, the fourth desorbed gas is pressurized before being injected into the blast furnace; preferably, the pressurized gas pressure of the fourth desorbed gas is 0.3 to 0.4 MPa.

[0027] Furthermore, the hydrogen-based vertical shaft furnace top gas undergoes heat exchange treatment before decarbonization and denitrification, and before being used as the first fuel gas. Preferably, the heat exchange treatment includes reducing the temperature of the hydrogen-based vertical shaft furnace top gas to 40°C or below through heat exchange. More preferably, the heat exchange includes multi-stage heat exchange, comprising primary and secondary heat exchange. The primary heat exchange includes exchanging heat between the hydrogen-based vertical shaft furnace top gas and the third decarbonized and denitrified gas. The secondary heat exchange includes exchanging heat between the hydrogen-based vertical shaft furnace top gas after primary heat exchange and a cooling liquid, thereby reducing the temperature of the hydrogen-based vertical shaft furnace top gas to 40°C or below. Most preferably, after the hydrogen-based vertical shaft furnace top gas exchanges heat with the third decarbonized and denitrified gas, the temperature of the third decarbonized and denitrified gas rises to 323–439°C. Cooling water can be used as the cooling liquid.

[0028] Furthermore, the reducing gas is heated and then introduced into a hydrogen-based vertical shaft furnace to produce sponge iron; preferably, the reducing gas is heated to 950-1050°C and then introduced into a hydrogen-based vertical shaft furnace to produce sponge iron.

[0029] Furthermore, the hydrogen content of the reducing gas is 55-95.5%, and the H2 / CO ratio is ≥1.4. When the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the amount of the reducing gas introduced is 243,550-317,000 Nm³. 3 At a pressure of 0.3–0.4 MPa and a temperature of 950–1050 °C, the metallization rate of the produced sponge iron is 93–95%, and the carbon content is 0.2–3.5%.

[0030] Furthermore, when the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the flow rate of the FINEX gas is 2980–83800 Nm³. 3 / h, temperature 20~50℃; at this time, the calorific value of the first decarbonized gas obtained by the decarbonization treatment of the FINEX gas is 1.45~1.55 times that of the portion of FINEX gas, and the gas volume is 2000~56200Nm³. 3 The gas pressure is 0.4–0.5 MPa, and the temperature after heating is 950–1050 °C; furthermore, the calorific value of the first desorbed gas is 17–18% of the calorific value of the FINEX gas, and the gas volume is 985–27680 Nm³. 3 / h, temperature 20~50℃.

[0031] Furthermore, when the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the converter gas volume is 7200–100000 Nm³. 3 / h, temperature 20~50℃; at this time, the calorific value of the second decarbonized gas obtained by decarbonization treatment of the converter gas is 1.05~1.25 times that of the converter gas, and the gas volume is 5700~79000Nm³. 3 The gas pressure is 0.4–0.5 MPa, and the temperature after heating is 950–1050 °C; furthermore, the calorific value of the obtained second desorbed gas is 35–40% of the calorific value of the converter gas, and the gas volume is 1500–21200 Nm³. 3 / h, temperature 20~50℃.

[0032] Furthermore, when the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the hydrogen content of the top gas from the hydrogen-based shaft furnace is 38-72%, the CO content is 1-26.5%, and the gas volume is 248,000-319,000 Nm³. 3 / h, gas pressure 0.16~0.26MPa, temperature 418~534℃; at this time, the calorific value of the third decarbonized and denitrified gas obtained by separating a portion of the hydrogen-based vertical furnace top gas after decarbonization and denitrification treatment is 1.32~1.40 times that of a portion of the hydrogen-based vertical furnace top gas, and the gas volume is 131000~181000Nm³. 3 / h, gas pressure 0.4~0.5MPa, temperature after heating 950~1050℃; furthermore, the calorific value of the obtained third desorbed gas is 32.5~88.3% of the calorific value of a portion of the hydrogen-based vertical shaft furnace top gas, and the gas volume is 6200~60500Nm³. 3 / h, temperature 20~50℃.

[0033] Furthermore, when the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the volume of coke oven gas is 69,600–196,000 Nm³. 3 The gas flow rate is 20–50℃, and the pressurized gas pressure is 0.45–0.55 MPa. At this time, the hydrogen obtained from the coke oven gas after hydrogen extraction has a calorific value of 60–70% of the calorific value of the coke oven gas, and the gas flow rate is 33000–93000 Nm³. 3 The gas pressure is 0.4–0.5 MPa, and the temperature after heating is 950–1050 °C; furthermore, the calorific value of the obtained fourth desorbed gas is 1.15–1.45 times that of the coke oven gas, and the gas volume is 36600–104000 Nm³. 3 / h, temperature 20~50℃; the fourth desorbed gas is pressurized and injected into the blast furnace through the tuyeres for low-carbon smelting, and oxygen enrichment is carried out at the same time as injection, with an oxygen enrichment rate of 14~58%, the coke ratio of the blast furnace is reduced by 25~78kg / tHM, and CO2 emissions are reduced by 6.7~20.8%; preferably, the pressure of the fourth desorbed gas after pressurization is 0.3~0.4MPa.

[0034] It should be noted that the hourly gas volume mentioned in this invention is set for a 1 million-ton-per-year sponge iron shaft furnace. When the annual production of sponge iron changes, the gas volume also needs to be adjusted accordingly.

[0035] The second aspect of the present invention provides a secondary energy recovery and utilization system for steel plants and a hydrogen metallurgical system, the system comprising a third gas treatment unit, a fourth gas treatment unit, a heating device, a hydrogen-based vertical shaft furnace and a blast furnace, the system further comprising a first gas treatment unit and a second gas treatment unit, or the system further comprising a first gas treatment unit.

[0036] The first gas processing unit is used to process FINEX gas and includes a first decarbonization device. The first decarbonization device is used to decarbonize the FINEX gas, separate the FINEX gas into a first decarbonized gas and a first desorbed gas, and is provided with a first decarbonized gas outlet end, which is connected to the heating device.

[0037] The second gas treatment unit is used to treat converter gas and includes a first decarbonization device. The first decarbonization device is used to decarbonize the converter gas, divide the converter gas into a second decarbonized gas and a second desorbed gas, and is provided with a second decarbonized gas outlet end, which is connected to the heating device.

[0038] The third gas treatment unit is used to treat the top gas of the hydrogen-based vertical furnace, including a third decarbonization and denitrification device; the third decarbonization and denitrification device is used to remove CO2 and N2 from the top gas of the hydrogen-based vertical furnace, divide the top gas of the hydrogen-based vertical furnace into third decarbonization and denitrification gas and third desorption gas, and is provided with a third decarbonization and denitrification gas outlet end, which is connected to the heating device;

[0039] The fourth gas processing unit is used to process coke oven gas, including a fourth hydrogen extraction device; the fourth hydrogen extraction device is used to extract hydrogen from coke oven gas, divide the coke oven gas into hydrogen and a fourth desorbed gas, and is provided with a hydrogen outlet end and a fourth desorbed gas outlet end, the hydrogen outlet end being connected to the heating device.

[0040] The heating device is used to heat the first decarburized gas, the second decarburized gas, the third decarburized and denitrified gas, and hydrogen; the heating device is provided with a reducing gas outlet end, which is connected to the hydrogen-based vertical furnace, and the hydrogen-based vertical furnace uses the reducing gas to produce sponge iron;

[0041] The fourth desorption gas outlet is connected to the blast furnace, and the blast furnace uses the fourth desorption gas for low-carbon smelting to produce liquid iron.

[0042] Furthermore, the system also includes a steelmaking workshop, and the first decarburization device is further provided with a first desorption gas outlet end, which is connected to the steelmaking workshop to send the first desorption gas into the steelmaking workshop for CO2 steelmaking.

[0043] Furthermore, the system also includes a gas pipeline network, and the second decarbonization device is further provided with a second desorption gas outlet end, which is connected to the gas pipeline network to send the second desorption gas into the gas pipeline network.

[0044] Furthermore, the third decarbonization and denitrification device is also provided with a third desorption gas outlet end, and the heating device is provided with a second fuel gas inlet end. The third desorption gas outlet end is connected to the second fuel gas inlet end so as to send the third desorption gas into the heating device as fuel gas for heating.

[0045] Furthermore, the third desorption gas outlet is also connected to the gas pipeline network to deliver the third desorption gas into the gas pipeline network.

[0046] Furthermore, the second gas treatment unit also includes a second purification device, which is installed before the second decarbonization device and is used to purify the converter gas.

[0047] Furthermore, the fourth gas treatment unit also includes a fourth purification device, which is located before the fourth hydrogen extraction device and is used to purify the coke oven gas.

[0048] Furthermore, the first gas treatment unit also includes a first dust removal device, which is installed before the first decarbonization device and is used to remove dust from the FINEX gas.

[0049] Furthermore, the third gas treatment unit also includes a third dust removal device, which is used to remove dust from the top gas of the hydrogen-based vertical furnace.

[0050] Furthermore, the first gas treatment unit also includes a first compressor, which is used to pressurize the dust-removed FINEX gas; preferably, the first compressor is disposed between the first dust removal device and the first decarbonization device.

[0051] Furthermore, the second gas treatment unit also includes a second compressor, which is used to pressurize the purified converter gas; preferably, the second compressor is disposed between the second purification device and the second decarbonization device.

[0052] Furthermore, the third gas treatment unit also includes a third compressor, which is used to pressurize the top gas of the hydrogen-based vertical furnace after heat exchange; preferably, the third compressor is located between the third dust removal device and the third decarbonization and denitrification device.

[0053] Furthermore, the fourth gas treatment unit also includes a fourth compressor, which is used to pressurize the coke oven gas; preferably, the fourth compressor is located between the fourth purification device and the fourth hydrogen extraction device.

[0054] Furthermore, the fourth gas treatment unit also includes a fifth compressor, which is located between the fourth hydrogen extraction device and the blast furnace and is used to pressurize the fourth desorbed gas.

[0055] Furthermore, the third gas treatment unit also includes a heat exchange device for heat exchange treatment of the top gas from the hydrogen-based vertical furnace. Preferably, the heat exchange device is located between the third dust removal device and the third compressor. The heat exchange device includes a multi-stage heat exchanger, which includes a primary heat exchanger and a secondary heat exchanger connected in sequence. The primary heat exchanger is connected to the outlet end of the third decarbonized and denitrified gas and serves as the site for heat exchange between the third decarbonized and denitrified gas and the top gas from the hydrogen-based vertical furnace. The secondary heat exchanger serves as the site for heat exchange between the coolant and the top gas from the hydrogen-based vertical furnace.

[0056] Furthermore, the heating device is also provided with a first fuel gas inlet, which is the inlet for feeding hydrogen-based vertical furnace top gas into the heating device, so as to feed hydrogen-based vertical furnace top gas into the heating device as fuel gas for heating; preferably, the first fuel gas inlet is connected to the hydrogen-based vertical furnace top gas outlet of the heat exchange device, so as to feed a portion of the hydrogen-based vertical furnace top gas after heat exchange into the heating device as fuel gas for heating.

[0057] A third aspect of the present invention provides the method according to the first aspect and / or the system according to the second aspect in the field of hydrogen metallurgy and their application.

[0058] As described above, the steel plant secondary energy recovery and utilization and hydrogen metallurgy method, system and application of the present invention have the following beneficial effects:

[0059] 1) This invention extracts and utilizes H2 from coke oven gas, CO from converter gas, and CO from hydrogen- and oxygen-enriched FINEX gas as reducing gases. This not only makes full use of the steel plant's secondary energy reduction capacity, but also uses a mature and simple gas removal device to replace the reforming converter, which has a higher investment cost, thus reducing the primary energy consumption and equipment investment of the hydrogen-based vertical shaft furnace.

[0060] 2) In the method of the present invention, the volume fraction of reducing gas H2 is 55-96.5%, and the temperature is controlled at 950-1050℃, which ensures a high reducing capacity; the volume fraction of CO is 1.2-37%, which can effectively achieve a carburization amount of 0.2-3.5% for sponge iron.

[0061] 3) This invention injects the methane-rich desorbed gas (i.e., the fourth desorbed gas) after hydrogen extraction from coke oven gas into the blast furnace, while simultaneously performing oxygen enrichment operations. This can reduce the coke ratio of the blast furnace and decrease CO2 emissions from the combined steel plant while maintaining the original blast furnace belly gas volume and theoretical combustion temperature basically unchanged.

[0062] In summary, the technology provided by this invention addresses the technical problems of secondary energy recovery and utilization in steel plants and avoidance of high-investment reforming and conversion, offering a low-carbon and efficient new method for hydrogen metallurgy. This is of great significance for simplifying the process flow of hydrogen-based vertical shaft furnaces and reducing carbon emissions from blast furnaces. Attached Figure Description

[0063] Figure 1 The diagram shows the layout of the secondary energy recovery and hydrogen metallurgy system in a steel plant according to one embodiment and Examples 1-8 of the present invention.

[0064] Figure 2 The diagram shows the layout of the secondary energy recovery and hydrogen metallurgy system in a steel plant in another embodiment and Examples 9-11 of the present invention.

[0065] Figure 3 The diagram shows the layout of the secondary energy recovery and hydrogen metallurgy system in a steel plant in another embodiment and Example 12 of the present invention.

[0066] Explanation of reference numerals in the attached figures:

[0067] First coarse dust collector 11, first fine dust collector 12, first press 13, first decarburization device 14, second press 21, second decarburization device 22, third coarse dust collector 31, third fine dust collector 32, heat exchange device 33, third press 34, third decarburization and denitrification device 35, fourth press 41, fourth hydrogen extraction device 42, fifth press 43, heating device 50, hydrogen-based vertical shaft furnace 60, blast furnace 70, gas pipeline network 80, steelmaking workshop 90. Detailed Implementation

[0068] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0069] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0070] One embodiment of the present invention provides a method for secondary energy recovery and utilization in steel plants and hydrogen metallurgy, comprising the following steps:

[0071] Obtain by-product coal gas from steel plants, separate the reducing gas, and introduce it into a hydrogen-based vertical shaft furnace to produce sponge iron. The top coal gas discharged from the top of the hydrogen-based vertical shaft furnace is recycled.

[0072] The by-product gas from the steel plant includes FINEX gas, converter gas, hydrogen-based vertical shaft furnace top gas, and coke oven gas.

[0073] The reducing gas includes a third decarbonization and denitrification gas and hydrogen, and also includes a first decarbonization gas and / or a second decarbonization gas;

[0074] The first decarbonized gas is obtained by separating the FINEX gas through decarbonization treatment; the second decarbonized gas is obtained by separating the converter gas through decarbonization treatment; the third decarbonized and denitrified gas is obtained by separating the hydrogen-based vertical shaft furnace top gas through decarbonization and denitrification treatment; and the hydrogen is obtained by separating the coke oven gas through hydrogen extraction treatment.

[0075] The coke oven gas is separated into hydrogen and a fourth desorbed gas after hydrogen extraction treatment. The fourth desorbed gas is injected into the blast furnace for low-carbon smelting to produce liquid iron.

[0076] The composition of reducing gases specifically includes the following three methods:

[0077] 1. It is a reducing gas composed of a mixture of the second decarbonization gas, the third decarbonization and denitrification gas, and hydrogen.

[0078] 2. The reducing gas is composed of a mixture of the first decarbonization gas, the third decarbonization and denitrification gas, and hydrogen.

[0079] 3. The reducing gas is composed of a mixture of the first decarbonization gas, the second decarbonization gas, the third decarbonization and denitrification gas, and hydrogen.

[0080] The method described above extracts and utilizes H2 from coke oven gas, CO from converter gas, and CO and H2 from finex gas as reducing gases. This fully utilizes the reducing capacity of the steel plant's secondary energy source and replaces the more expensive reforming converter with a mature and simple gas removal device, reducing the primary energy consumption and equipment investment of the hydrogen-based vertical shaft furnace. By injecting the methane-rich desorbed gas (i.e., the fourth desorbed gas) after hydrogen extraction from coke oven gas into the blast furnace and simultaneously performing oxygen enrichment, the coke ratio of the blast furnace can be reduced while maintaining the original blast furnace belly gas volume and theoretical combustion temperature basically unchanged, thereby reducing CO2 emissions from the combined steel plant.

[0081] In another embodiment of the present invention, the FINEX gas is decarbonized to obtain the first decarbonized gas and the first desorbed gas. The first desorbed gas is transported to the steelmaking workshop for CO2 steelmaking, thereby realizing the full utilization of the FINEX gas.

[0082] In another embodiment of the present invention, the converter gas is decarbonized to obtain the second decarbonized gas and the second desorbed gas. The second desorbed gas is transported to the steel plant gas pipeline network, which can realize the full utilization of the converter gas.

[0083] In another embodiment of the present invention, the method further includes: separating a portion of the hydrogen-based vertical furnace top gas through decarbonization and denitrification to obtain the third decarbonized and denitrified gas, and using another portion of the hydrogen-based vertical furnace top gas as a first fuel gas to heat the reducing gas; preferably, the volume fraction of the other portion of the hydrogen-based vertical furnace top gas used as the first fuel gas is 3.5 to 30.5%.

[0084] In another embodiment of the present invention, a portion of the top gas from the hydrogen-based vertical furnace is decarbonized and denitrified to obtain the third decarbonized and denitrified gas and the third desorbed gas. A portion of the third desorbed gas is used as a second fuel gas to heat the reducing gas.

[0085] In another embodiment of the present invention, another portion of the third desorbed gas is supplied to the steel plant's gas pipeline network. The above embodiments utilize the third desorbed gas in two parts, achieving full utilization of the hydrogen-based vertical shaft furnace top gas.

[0086] In one specific embodiment, the volume ratio of the first fuel gas to the second fuel gas is ≥3. That is, in the fuel gas required for heating the reducing gas, the volume percentage of the other part of the hydrogen-based vertical furnace top gas is ≥75% (i.e., the amount of the first fuel gas used), and the volume percentage of the third desorbed gas is ≤25% (i.e., the amount of the second fuel gas used).

[0087] The above-described embodiment uses the third desorbed gas and a portion of the hydrogen-based vertical shaft furnace top gas as fuel gas to heat the reducing gas, thus eliminating the need for external fuel and achieving self-sufficiency. It should be noted that the second fuel gas is an optional fuel gas or can be considered as supplementary fuel gas. When the first fuel gas is insufficient, a portion of the third desorbed gas can be selected as supplementary fuel gas for heating the reducing gas.

[0088] In another embodiment of the present invention, the converter gas is further purified before being decarbonized.

[0089] In another embodiment of the present invention, the coke oven gas is further purified before being subjected to hydrogen extraction.

[0090] The purification treatment in the above embodiments refers to desulfurization purification treatment, that is, removing organic and inorganic sulfur from the coal gas. Preferably, the total sulfur content of the coke oven / converter gas after desulfurization treatment is ≤10mg / m³. 3 .

[0091] In another embodiment of the present invention, the FINEX gas undergoes dust removal treatment before decarbonization; preferably, the dust removal treatment of the FINEX gas includes coarse dust removal and wet dust removal; more preferably, the dust content of the FINEX gas after coarse dust removal is ≤6g / Nm³. 3 The dust content of FINEX gas after wet dust removal is ≤5mg / Nm³. 3 .

[0092] In another embodiment of the present invention, the hydrogen-based vertical shaft furnace top gas undergoes dust removal treatment before being decarbonized and denitrified, and before being used as the first fuel gas; preferably, the dust removal treatment of the hydrogen-based vertical shaft furnace top gas includes coarse dust removal and dry dust removal; more preferably, the dust content of the hydrogen-based vertical shaft furnace top gas after coarse dust removal is ≤6g / Nm³. 3 The dust content of the top gas from the hydrogen-based vertical shaft furnace after dry dust removal is ≤5mg / Nm³. 3 .

[0093] In another embodiment of the present invention, the method further includes: pressurizing the FINEX gas after dust removal and before decarbonization treatment; preferably, the pressurized FINEX gas has a pressure of 0.45 to 0.55 MPa, and the first decarbonized gas obtained after decarbonization treatment has a pressure of 0.4 to 0.5 MPa.

[0094] In another embodiment of the present invention, the method further includes: pressurizing the fourth desorbed gas before injecting it into the blast furnace for low-carbon smelting; preferably, the pressurized fourth desorbed gas has a pressure of 0.3 to 0.4 MPa.

[0095] In another embodiment of the present invention, the method further includes: pressurizing the converter gas after purification treatment and before decarbonization treatment; preferably, the pressurized converter gas has a pressure of 0.45-0.55 MPa, and the pressure of the second decarbonized gas obtained after decarbonization treatment of the converter gas is 0.4-0.5 MPa.

[0096] In another embodiment of the present invention, the method further includes: pressurizing a portion of the hydrogen-based vertical furnace top gas before decarbonizing and denitrifying it; preferably, the pressurized hydrogen-based vertical furnace top gas has a pressure of 0.45 to 0.55 MPa, and the pressure of the third decarbonized and denitrified gas obtained after decarbonizing and denitrifying the portion of the hydrogen-based vertical furnace top gas is 0.4 to 0.5 MPa.

[0097] In another embodiment of the present invention, the method further includes: pressurizing the coke oven gas after purification treatment and before hydrogen extraction treatment; preferably, the pressurized coke oven gas has a pressure of 0.45-0.55 MPa, and the hydrogen obtained after hydrogen extraction treatment of the coke oven gas has a pressure of 0.4-0.5 MPa.

[0098] In another embodiment of the present invention, the method further includes: after dust removal from the top gas of the hydrogen-based vertical furnace, before pressurizing and decarbonizing / denitrifying a portion of the top gas of the hydrogen-based vertical furnace, and before using another portion of the top gas of the hydrogen-based vertical furnace as fuel gas for heating reducing gases, performing heat exchange treatment on it; preferably, the heat exchange treatment includes: reducing the temperature of the top gas of the hydrogen-based vertical furnace to 40°C or below through heat exchange; more preferably, the heat exchange includes multi-stage heat exchange, the multi-stage heat exchange includes primary heat exchange and secondary heat exchange, the primary heat exchange includes: exchanging heat between the top gas of the hydrogen-based vertical furnace and the third decarbonized / denitrified gas, the secondary heat exchange includes: exchanging heat between the top gas of the hydrogen-based vertical furnace after primary heat exchange and a cooling liquid, so as to reduce the temperature of the top gas of the hydrogen-based vertical furnace to 40°C or below; most preferably, after the top gas of the hydrogen-based vertical furnace exchanges heats with the third decarbonized / denitrified gas, the temperature of the third decarbonized / denitrified gas increases to 323-439°C. Cooling water can be used as the coolant.

[0099] The above-described implementation method reduces the temperature of the top gas of the hydrogen-based vertical furnace through heat exchange, which facilitates decarbonization and denitrification treatment. By exchanging heat with the third decarbonization and denitrification gas, the residual heat of the top gas of the hydrogen-based vertical furnace is fully utilized to increase the temperature of the third decarbonization and denitrification gas, which can reduce the demand for fuel gas in the heating process. In addition, in order to avoid the excessively high temperature of the top gas of the hydrogen-based vertical furnace after heat exchange with the third decarbonization and denitrification gas, which may have an adverse effect on decarbonization and denitrification, a secondary heat exchange with coolant can be used to control the temperature of the top gas of the hydrogen-based vertical furnace at 40°C or below.

[0100] In another embodiment of the present invention, the reducing gas is heated and then introduced into a hydrogen-based vertical shaft furnace to produce sponge iron; preferably, the reducing gas is heated to 950-1050°C and then introduced into a hydrogen-based vertical shaft furnace to produce sponge iron.

[0101] In another embodiment of the present invention, the hydrogen content of the reducing gas is 55-95.5%, and the H2 / CO ratio is ≥1.4. When the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the amount of reducing gas introduced is 243,550-317,000 Nm³. 3 At a pressure of 0.3–0.4 MPa and a temperature of 950–1050 °C, the metallization rate of the produced sponge iron is 93–95%, and the carbon content is 0.2–3.5%.

[0102] In the above embodiments, the volume fraction of the reducing gas H2 in the hydrogen-based vertical furnace is controlled at 55-96.5%, and the temperature is controlled at 950-1050℃, thus ensuring a high reduction capacity; the volume fraction of CO is controlled at 1.2-37%, which can effectively achieve a carburization amount of 0.2-3.5% for sponge iron.

[0103] To achieve the aforementioned technical effects, in one specific embodiment, when the hydrogen-based shaft furnace produces 1 million tons of sponge iron annually, the flow rate of the FINEX gas is 2980–83800 Nm³. 3 / h, temperature 20~50℃; at this time, the calorific value of the first decarbonized gas obtained by the decarbonization treatment of the FINEX gas is 1.45~1.55 times that of the portion of FINEX gas, and the gas volume is 2000~56200Nm³. 3 The gas pressure is 0.4–0.5 MPa, and the temperature after heating is 950–1050 °C; furthermore, the calorific value of the first desorbed gas is 17–18% of the calorific value of the FINEX gas, and the gas volume is 985–27680 Nm³. 3 / h, temperature 20~50℃.

[0104] In one specific embodiment, when the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the converter gas flow rate is 7200-100000 Nm³. 3 / h, temperature 20~50℃; at this time, the calorific value of the second decarbonized gas obtained by decarbonization treatment of the converter gas is 1.05~1.25 times that of the converter gas, and the gas volume is 5700~79000Nm³. 3 The gas pressure is 0.4–0.5 MPa, and the temperature after heating is 950–1050 °C; furthermore, the calorific value of the obtained second desorbed gas is 35–40% of the calorific value of the converter gas, and the gas volume is 1500–21200 Nm³. 3 / h, temperature 20~50℃.

[0105] In one specific embodiment, when the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the hydrogen content of the top gas from the hydrogen-based shaft furnace is 38-72%, the CO content is 1-26.5%, and the gas volume is 248,000-319,000 Nm³. 3 / h, gas pressure 0.16~0.26MPa, temperature 418~534℃; at this time, the calorific value of the third decarbonized and denitrified gas obtained by separating a portion of the hydrogen-based vertical furnace top gas after decarbonization and denitrification treatment is 1.32~1.40 times that of a portion of the hydrogen-based vertical furnace top gas, and the gas volume is 131000~181000Nm³. 3 / h, gas pressure 0.4~0.5MPa, temperature after heating 950~1050℃; furthermore, the calorific value of the obtained third desorbed gas is 32.5~88.3% of the calorific value of a portion of the hydrogen-based vertical shaft furnace top gas, and the gas volume is 6200~60500Nm³. 3 / h, temperature 20~50℃.

[0106] In one specific embodiment, when the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the coke oven gas volume is 69,600–196,000 Nm³. 3 The gas flow rate is 20–50℃, and the pressurized gas pressure is 0.45–0.55 MPa. At this time, the hydrogen obtained from the coke oven gas after hydrogen extraction has a calorific value of 60–70% of the calorific value of the coke oven gas, and the gas flow rate is 33000–93000 Nm³. 3 The gas pressure is 0.4–0.5 MPa, and the temperature after heating is 950–1050 °C; furthermore, the calorific value of the obtained fourth desorbed gas is 1.15–1.45 times that of the coke oven gas, and the gas volume is 36600–104000 Nm³. 3 / h, temperature 20~50℃; the fourth desorbed gas is pressurized and injected into the blast furnace through the tuyeres for low-carbon smelting, and oxygen enrichment is carried out at the same time as injection, with an oxygen enrichment rate of 14~58%, the coke ratio of the blast furnace is reduced by 25~78kg / tHM, and CO2 emissions are reduced by 6.7~20.8%; preferably, the pressure of the fourth desorbed gas after pressurization is 0.3~0.4MPa.

[0107] In the above embodiments, the methods for hydrogen extraction, decarbonization, and decarbonization / denitrification can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption. These methods are all prior art, and will not be described in detail here.

[0108] It should be noted that the hourly gas volume involved in the above embodiments and subsequent embodiments of the present invention is set for a production capacity of 1 million tons of sponge iron per year. When the annual production capacity of sponge iron changes, the gas volume also needs to be adjusted accordingly. Those skilled in the art can refer to the embodiments and examples of the present invention to design and adjust according to actual conditions and needs.

[0109] Smelting reduction ironmaking is a crucial process in ironmaking and a key area for future research and development. Besides the FINEX process, the COREX and HIsmelt processes are currently in commercial production. The COREX process has been successfully applied in countries like China, South Africa, and India; while the HIsmelt process was introduced to China relatively recently and is currently in the process of digestion and absorption. Domestic ironmaking researchers are also conducting in-depth research on the HIsmelt process. Blast furnace top gas, COREX gas, and HIsmelt gas, like FINEX gas, contain CO and H2 and can be used as supplementary gas for hydrogen-based shaft furnace reduction after decarburization. However, it's important to note that the application scenarios for FINEX, COREX, and HIsmelt processes differ, and there is currently no scenario where they coexist in a single plant. Therefore, any one of blast furnace top gas, COREX gas, and HISmelt gas can be used to replace the FINEX gas in the above embodiments / examples of the present invention, or the blast furnace top gas can be used in combination with at least one of the FINEX gas and converter gas in the above embodiments / examples of the present invention, and then decarbonized according to the same / similar methods in the above embodiments / examples of the present invention before reuse.

[0110] Please refer to Figures 1 to 3 One embodiment of the present invention provides a secondary energy recovery and utilization system for steel plants and a hydrogen metallurgical system, including a third gas treatment unit, a fourth gas treatment unit, a heating device 50, a hydrogen-based vertical shaft furnace 60 and a blast furnace 70. The system also includes a first gas treatment unit and / or a second gas treatment unit.

[0111] The first gas processing unit is used to process FINEX gas, including a first decarbonization device 14. The first decarbonization device 14 is used to decarbonize the FINEX gas, separate the FINEX gas into a first decarbonized gas and a first desorbed gas, and is provided with a first decarbonized gas outlet end, which is connected to the heating device 50.

[0112] The second gas treatment unit is used to treat converter gas, including a first decarbonization device 14. The first decarbonization device 14 is used to decarbonize the converter gas, divide the converter gas into second decarbonized gas and second desorbed gas, and is provided with a second decarbonized gas outlet end, which is connected to the heating device 50.

[0113] The third gas treatment unit is used to treat the top gas of the hydrogen-based vertical furnace 60, including the third decarbonization and denitrification device 35; the third decarbonization and denitrification device 35 is used to remove CO2 and N2 from the top gas of the hydrogen-based vertical furnace 60, divide the top gas of the hydrogen-based vertical furnace 60 into the third decarbonization and denitrification gas and the third desorption gas, and is provided with the third decarbonization and denitrification gas outlet end, which is connected to the heating device 50;

[0114] The fourth gas processing unit is used to process coke oven gas, including the fourth hydrogen extraction device 42; the fourth hydrogen extraction device 42 is used to extract hydrogen from coke oven gas, divide coke oven gas into hydrogen and fourth desorbed gas, and is provided with a hydrogen outlet end and a fourth desorbed gas outlet end, the hydrogen outlet end being connected to the heating device 50.

[0115] The heating device 50 is used to heat the first decarburized gas, the second decarburized gas, the third decarburized and denitrified gas and hydrogen; the heating device 50 is provided with a reducing gas outlet end, which is connected to the hydrogen-based vertical furnace 60, which uses reducing gas to produce sponge iron.

[0116] The fourth desorption gas outlet is connected to blast furnace 70, which uses the fourth desorption gas for low-carbon smelting to produce molten iron.

[0117] In another embodiment of the present invention, the system further includes a steelmaking workshop 90, and the first decarburization device 14 is further provided with a first desorption gas outlet end, which is connected to the steelmaking workshop 90 to send the first desorption gas into the steelmaking workshop 90 for CO2 steelmaking.

[0118] In another embodiment of the present invention, the system further includes a gas pipeline network 80, and the second decarbonization device 22 is further provided with a second desorption gas outlet end, which is connected to the gas pipeline network 80 to send the second desorption gas into the gas pipeline network 80.

[0119] In another embodiment of the present invention, the third decarbonization and denitrification device 35 is further provided with a third desorption gas outlet end, and the heating device 50 is provided with a second fuel gas inlet end. The third desorption gas outlet end is connected to the second fuel gas inlet end so as to send the third desorption gas into the heating device 50 as fuel gas for heating.

[0120] In another embodiment of the present invention, the third desorption gas outlet is also connected to the gas pipeline 80 to send the third desorption gas into the gas pipeline 80.

[0121] In another embodiment of the present invention, the second gas treatment unit further includes a second purification device (not shown in the figure), which is disposed before the second decarbonization device 22 and is used to purify the converter gas.

[0122] In another embodiment of the present invention, the fourth gas treatment unit further includes a fourth purification device (not shown in the figure), which is disposed before the fourth hydrogen extraction device 42 and is used to purify the coke oven gas.

[0123] In another embodiment of the present invention, the first gas treatment unit further includes a first dust removal device, which is disposed before the first decarbonization device 14 and is used to perform dust removal treatment on the FINEX gas.

[0124] In another embodiment of the present invention, the third gas treatment unit further includes a third dust removal device for dust removal treatment of the top gas of the hydrogen-based vertical furnace 60.

[0125] In another embodiment of the present invention, the first gas treatment unit further includes a first compressor 13, which is used to pressurize the dust-removed FINEX gas; preferably, the first compressor 13 is disposed between the first dust removal device and the first decarbonization device 14.

[0126] In another embodiment of the present invention, the second gas treatment unit further includes a second pressurizer 21, which is used to pressurize the purified converter gas; preferably, the second pressurizer 21 is disposed between the second purification device and the second decarbonization device 22.

[0127] In another embodiment of the present invention, the third gas treatment unit further includes a third pressurizer 34, which is used to pressurize the top gas of the hydrogen-based vertical furnace 60 after heat exchange; preferably, the third pressurizer 34 is disposed between the third dust removal device and the third decarbonization and denitrification device 35.

[0128] In another embodiment of the present invention, the fourth gas treatment unit further includes a fourth pressurizer 41, which is used to pressurize the coke oven gas; preferably, the fourth pressurizer 41 is disposed between the fourth purification device and the fourth hydrogen extraction device 42.

[0129] In another embodiment of the present invention, the fourth gas treatment unit further includes a fifth compressor 43, which is disposed between the fourth hydrogen extraction device 42 and the blast furnace 70, and is used to pressurize the fourth desorbed gas.

[0130] In another embodiment of the present invention, the third gas treatment unit further includes a heat exchange device 33, which is used to perform heat exchange treatment on the top gas of the hydrogen-based vertical furnace 60. Preferably, the heat exchange device 33 is disposed between the third dust removal device and the third compressor 34. The heat exchange device 33 includes a multi-stage heat exchanger, which includes a primary heat exchanger and a secondary heat exchanger connected in sequence. The primary heat exchanger is connected to the outlet end of the third decarbonized and denitrified gas and serves as the site for heat exchange between the third decarbonized and denitrified gas and the top gas of the hydrogen-based vertical furnace 60. The secondary heat exchanger serves as the site for heat exchange between the coolant and the top gas of the hydrogen-based vertical furnace 60.

[0131] In another embodiment of the present invention, the heating device 50 is further provided with a first fuel gas inlet end, which is the inlet for feeding the top coal gas of the hydrogen-based vertical furnace 60 into the heating device 50, so as to feed the top coal gas of the hydrogen-based vertical furnace 60 into the heating device 50 as fuel gas for heating; preferably, the first fuel gas inlet end is connected to the outlet end of the top coal gas of the hydrogen-based vertical furnace 60 of the heat exchange device 33, so as to feed a portion of the top coal gas of the hydrogen-based vertical furnace 60 after heat exchange into the heating device 50 as fuel gas for heating.

[0132] like Figure 1 As shown, one embodiment of the present invention provides a secondary energy recovery and utilization system for steel plants and a hydrogen metallurgical system, including a second gas treatment unit, a third gas treatment unit, a fourth gas treatment unit, a heating device 50, a hydrogen-based vertical shaft furnace 60, a blast furnace 70, and a gas pipeline network 80.

[0133] Specifically, the second gas treatment unit includes a second purification device, a second compressor 21, and a second decarbonization device 22 connected in sequence. After being purified by the second purification device and pressurized by the second compressor 21, the converter gas enters the second decarbonization device 22 for decarbonization and is divided into second decarbonized gas and second desorbed gas. The second decarbonization device 22 is provided with a second decarbonized gas outlet and a second desorbed gas outlet. The second decarbonized gas outlet is connected to the heating device 50, and the second desorbed gas outlet is connected to the gas pipeline network 80 to send the second desorbed gas into the gas pipeline network 80.

[0134] The third gas treatment unit includes a third dust removal device, a heat exchange device 33, a third compressor 34, and a third decarbonization and denitrification device 35, sequentially connected from the top gas outlet of the hydrogen-based vertical furnace. The third dust removal device includes a third coarse dust collector 31 and a third fine dust collector 32, with the third fine dust collector 32 preferably being a dry dust collector. After coarse and dry dust removal, the top gas from the hydrogen-based vertical furnace 60 undergoes a primary heat exchange with the third decarbonization and denitrification gas in the heat exchange device 33, followed by a secondary heat exchange with the coolant. Then, a portion of the top gas from the hydrogen-based vertical furnace 60 enters the third compressor 34, and after pressurization, it enters the third decarbonization and denitrification device 35. 5. After removing CO2 and N2, the gas is divided into third decarbonization and denitrification gas and third desorption gas. The third decarbonization and denitrification device 35 is equipped with a third decarbonization and denitrification gas outlet and a third desorption gas outlet. The third decarbonization and denitrification gas outlet is connected to the heating device 50, and the third desorption gas outlet is connected to the second fuel gas inlet to send the third desorption gas into the heating device 50 as fuel gas for heating. The third desorption gas outlet is also connected to the gas pipeline 80 to send the third desorption gas into the gas pipeline 80. Another part of the top gas from the hydrogen-based vertical furnace 60 is directly fed into the heating device 50 after heat exchange as fuel gas.

[0135] The fourth gas treatment unit includes a fourth purification device, a fourth pressurizer 41, a fourth hydrogen extraction device 42, and a fifth pressurizer 43 connected in sequence. After being purified by the fourth purification device and pressurized by the fourth pressurizer 41, the coke oven gas enters the fourth hydrogen extraction device 42 to extract hydrogen and is divided into hydrogen and fourth desorbed gas. The fourth hydrogen extraction device 42 is provided with a hydrogen outlet and a fourth desorbed gas outlet. The hydrogen outlet is connected to the heating device 50. The fourth desorbed gas outlet and the fifth pressurizer 43 are connected in sequence to the blast furnace 70. After being pressurized by the fifth pressurizer 43, the fourth desorbed gas is injected into the blast furnace 70 through the tuyeres for low-carbon smelting.

[0136] The heating device 50 is used to heat hydrogen, the second decarburization gas and the third decarburization and denitrification gas. The hydrogen, the second decarburization gas and the third decarburization and denitrification gas are mixed in the heating device 50 to form a reducing gas. The heating device 50 is provided with a reducing gas outlet end, which is connected to the hydrogen-based vertical furnace 60. The hydrogen-based vertical furnace 60 uses the reducing gas to produce sponge iron.

[0137] Blast Furnace 70 uses the fourth desorption gas for low-carbon smelting to produce liquid iron.

[0138] like Figure 2 As shown, another embodiment of the present invention provides a secondary energy recovery and utilization system for steel plants and a hydrogen metallurgical system, including a first gas treatment unit, a third gas treatment unit, a fourth gas treatment unit, a heating device 50, a hydrogen-based vertical shaft furnace 60, a blast furnace 70, a gas pipeline network 80, and a steelmaking workshop 90.

[0139] Specifically, the first gas treatment unit includes a first dust removal device, a first compressor 13, and a first decarbonization device 14 connected in sequence from the FINEX gas outlet. The first dust removal device includes a first coarse dust collector 11 and a first fine dust collector. The first fine dust collector is preferably a wet dust collector. After coarse dust removal, wet dust removal, and pressurization, the FINEX gas enters the first decarbonization device 14 for decarbonization and is divided into first decarbonized gas and first desorbed gas. The first decarbonization device 14 is provided with a first decarbonized gas outlet end and a first desorbed gas outlet end. The first decarbonized gas outlet end is connected to the heating device 50, and the first desorbed gas outlet end is connected to the steelmaking workshop 90 to send the first desorbed gas into the steelmaking workshop 90 for CO2 steelmaking.

[0140] The third gas treatment unit includes a third dust removal device, a heat exchange device 33, a third compressor 34, and a third decarbonization and denitrification device 35, which are sequentially connected from the top gas outlet of the hydrogen-based vertical furnace. The third dust removal device includes a first coarse dust collector 11 and a dry dust collector. After coarse and dry dust removal, the top gas from the hydrogen-based vertical furnace undergoes a primary heat exchange with the third decarbonization and denitrification gas in the heat exchange device 33, followed by a secondary heat exchange with the coolant. Then, a portion of the top gas from the hydrogen-based vertical furnace enters the third compressor 34, and after pressurization, it enters the third decarbonization and denitrification device 35 to remove CO2 and N2. The gas is divided into a third decarbonization and denitrification gas and a third desorption gas. The third decarbonization and denitrification device 35 is equipped with a third decarbonization and denitrification gas outlet and a third desorption gas outlet. The third decarbonization and denitrification gas outlet is connected to the heating device 50, and the third desorption gas outlet is connected to the second fuel gas inlet to send the third desorption gas into the heating device 50 as fuel gas for heating. The third desorption gas outlet is also connected to the gas pipeline network 80 to send the third desorption gas into the gas pipeline network 80. Another part of the top gas of the hydrogen-based vertical furnace 60 is directly fed into the heating device 50 after heat exchange as fuel gas.

[0141] The fourth gas treatment unit includes a fourth purification device, a fourth pressurizer 41, and a fourth hydrogen extraction device 42 connected in sequence. After being purified by the fourth purification device and pressurized by the fourth pressurizer 41, the coke oven gas enters the fourth hydrogen extraction device 42 to extract hydrogen and is divided into hydrogen and fourth desorbed gas. The fourth hydrogen extraction device 42 is provided with a hydrogen outlet end and a fourth desorbed gas outlet end, wherein the hydrogen outlet end is connected to the heating device 50 and the fourth desorbed gas outlet end is connected to the blast furnace 70.

[0142] The heating device 50 is used to heat hydrogen, the second decarburization gas, the third decarburization and denitrification gas and the first decarburization gas. The hydrogen and the third decarburization and denitrification gas are mixed with the second decarburization gas and / or the first decarburization gas in the heating device 50 to form a reducing gas. The heating device 50 is provided with a reducing gas outlet end, which is connected to the hydrogen-based vertical shaft furnace 60. The hydrogen-based vertical shaft furnace 60 uses the reducing gas to produce sponge iron.

[0143] Blast Furnace 70 uses the fourth desorption gas for low-carbon smelting to produce liquid iron.

[0144] like Figure 3 As shown, another embodiment of the present invention provides a secondary energy recovery and utilization system for steel plants and a hydrogen metallurgical system, including a first gas treatment unit, a second gas treatment unit, a third gas treatment unit, a fourth gas treatment unit, a heating device 50, a hydrogen-based vertical shaft furnace 60, a blast furnace 70, a gas pipeline network 80, and a steelmaking workshop 90.

[0145] Specifically, the first gas treatment unit includes a first dust removal device, a first compressor 13, and a first decarbonization device 14 connected in sequence from the FINEX gas outlet. The first dust removal device includes a second coarse dust collector and a second fine dust collector. After coarse dust removal, wet dust removal, and pressurization, the FINEX gas enters the first decarbonization device 14 for decarbonization and is divided into a first decarbonized gas and a first desorbed gas. The first decarbonization device 14 is provided with a first decarbonized gas outlet end and a first desorbed gas outlet end. The first decarbonized gas outlet end is connected to the heating device 50, and the first desorbed gas outlet end is connected to the steelmaking workshop 90 to send the fourth desorbed gas into the steelmaking workshop 90 for CO2 steelmaking.

[0146] The second gas treatment unit includes a second purification device, a second compressor 21, and a second decarbonization device 22 connected in sequence. After being purified by the second purification device and pressurized by the second compressor 21, the converter gas enters the second decarbonization device 22 for decarbonization and is divided into second decarbonized gas and second desorbed gas. The second decarbonization device 22 is provided with a second decarbonized gas outlet and a second desorbed gas outlet. The second decarbonized gas outlet is connected to the heating device 50, and the second desorbed gas outlet is connected to the gas pipeline network 80 to send the second desorbed gas into the gas pipeline network 80.

[0147] The third gas treatment unit includes a third dust removal device, a heat exchange device 33, a third compressor 34, and a third decarbonization and denitrification device 35, which are sequentially connected from the top gas outlet of the hydrogen-based vertical furnace. The third dust removal device includes a first coarse dust collector 11 and a dry dust collector. After coarse and dry dust removal, the top gas from the hydrogen-based vertical furnace undergoes a primary heat exchange with the third decarbonization and denitrification gas in the heat exchange device 33, followed by a secondary heat exchange with the coolant. Then, a portion of the top gas from the hydrogen-based vertical furnace enters the third compressor 34, and after pressurization, it enters the third decarbonization and denitrification device 35 to remove CO2 and N2. The gas is divided into a third decarbonization and denitrification gas and a third desorption gas. The third decarbonization and denitrification device 35 is equipped with a third decarbonization and denitrification gas outlet and a third desorption gas outlet. The third decarbonization and denitrification gas outlet is connected to the heating device 50, and the third desorption gas outlet is connected to the second fuel gas inlet to send the third desorption gas into the heating device 50 as fuel gas for heating. The third desorption gas outlet is also connected to the gas pipeline network 80 to send the third desorption gas into the gas pipeline network 80. Another part of the top gas of the hydrogen-based vertical furnace 60 is directly fed into the heating device 50 after heat exchange as fuel gas.

[0148] The fourth gas treatment unit includes a fourth purification device, a fourth pressurizer 41, and a fourth hydrogen extraction device 42 connected in sequence. After being purified by the fourth purification device and pressurized by the fourth pressurizer 41, the coke oven gas enters the fourth hydrogen extraction device 42 to extract hydrogen and is divided into hydrogen and fourth desorbed gas. The fourth hydrogen extraction device 42 is provided with a hydrogen outlet end and a fourth desorbed gas outlet end, wherein the hydrogen outlet end is connected to the heating device 50 and the fourth desorbed gas outlet end is connected to the blast furnace 70.

[0149] The heating device 50 is used to heat hydrogen, the second decarburization gas, the third decarburization and denitrification gas and the first decarburization gas. The hydrogen and the third decarburization and denitrification gas are mixed with the second decarburization gas and / or the first decarburization gas in the heating device 50 to form a reducing gas. The heating device 50 is provided with a reducing gas outlet end, which is connected to the hydrogen-based vertical shaft furnace 60. The hydrogen-based vertical shaft furnace 60 uses the reducing gas to produce sponge iron.

[0150] Blast Furnace 70 uses the fourth desorption gas for low-carbon smelting to produce liquid iron.

[0151] In summary, the technology provided by the above embodiments of the present invention addresses the technical problem of utilizing secondary energy in steel plants and avoiding high-investment reforming and conversion, and provides a new low-carbon and efficient hydrogen metallurgical method. This is of great significance for reducing primary energy consumption of hydrogen-based vertical shaft furnaces and reducing carbon emissions from blast furnaces.

[0152] The following specific examples illustrate the present invention in detail. It should also be understood that the following examples are only for specific illustrative purposes and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0153] Example 1

[0154] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 1 The system shown will proceed as follows:

[0155] (1) Coke oven gas treatment process

[0156] like Figure 1 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0157] The volume of coke oven gas is 144647 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of hydrogen is 60% of that of coke oven gas, and the gas volume is 68500 Nm³. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0158] (2) Blast furnace low-carbon smelting process

[0159] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.45 times that of the coke oven gas, and the gas volume is 76147 Nm³. 3 / h, temperature 40℃, pressurized air pressure 0.4MPa.

[0160] The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment is applied, with an oxygen enrichment rate of 32%. This reduces the coke ratio in the blast furnace by 50 kg / tHM and lowers CO2 emissions by 13.3%.

[0161] (3) Converter gas treatment process

[0162] The purified converter gas is pressurized and decarburized to obtain a second decarburized gas and a second desorbed gas. The second decarburized gas is heated and used as part of the reducing gas, while the second desorbed gas is supplied to the steel plant's gas pipeline network. The decarburization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0163] The converter gas volume is 93252 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of the second decarbonization gas is 1.17 times that of the converter gas, and the gas volume is 73500 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the second desorbed gas is 38% of that of the converter gas, and the gas volume is 19752Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0164] (4) Hydrogen-based vertical furnace top gas circulation process

[0165] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0166] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 38.6%, the CO content is 12.2%, and the gas volume is 299064 Nm³. 3 / h, gas pressure 0.26MPa, temperature 507℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonization and denitrification gas and cooling water, resulting in a temperature reduction to ≤40℃. 15.4% of the top gas after heat exchange is used as fuel gas for heating reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonization and denitrification gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 412℃ for the third decarbonization and denitrification gas.

[0167] The calorific value of the third decarbonization and denitrification gas is 1.35 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 149,835 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 87.7% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 58113Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0168] (5) Hydrogen-based shaft furnace smelting process

[0169] Hydrogen, the second decarburization gas, and the third decarburization and denitrification gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas used for heating with the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0170] The reducing gas has a hydrogen content of 55.8%, an H2 / CO ratio of 3.2, and a flow rate of 295,824 Nm³. 3 / h, air pressure 0.4MPa, temperature 950℃. The metallization rate of sponge iron is ≥93%, and the carbon content is 2.0%.

[0171] Example 2

[0172] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 1 The system shown will proceed as follows:

[0173] (1) Coke oven gas treatment process

[0174] like Figure 1As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0175] The volume of coke oven gas is 161,540 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 76500 Nm³. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0176] (2) Blast furnace low-carbon smelting process

[0177] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 85040 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment is applied, with an oxygen enrichment rate of 39%. This reduces the coke ratio in the blast furnace by 60 kg / tHM and reduces CO2 emissions by 16%.

[0178] (3) Converter gas treatment process

[0179] The purified converter gas is pressurized and decarburized to obtain a second decarburized gas and a second desorbed gas. The second decarburized gas is heated and used as part of the reducing gas, while the second desorbed gas is supplied to the steel plant's gas pipeline network. The decarburization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0180] The converter gas volume is 67243 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of the second decarbonization gas is 1.17 times that of the converter gas, and the gas volume is 53000 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the second desorbed gas is 38% of that of the converter gas, and the gas volume is 14243Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0181] (4) Hydrogen-based vertical furnace top gas circulation process

[0182] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0183] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 47.3%, the CO content is 9.2%, and the gas volume is 294,491 Nm³. 3 / h, gas pressure 0.26MPa, temperature 484℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonized and denitrified gas and cooling water, resulting in a temperature reduction to ≤40℃. 14.5% of the top gas after heat exchange is used as fuel gas to heat the reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonized and denitrified gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 389℃ for the third decarbonized and denitrified gas.

[0184] The calorific value of the third decarbonization and denitrification gas is 1.37 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 157,531 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 82.3% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 44190Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0185] (5) Hydrogen-based shaft furnace smelting process

[0186] Hydrogen, the second decarburization gas, and the third decarburization and denitrification gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas used for heating with the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0187] The reducing gas has a hydrogen content of 66.5%, an H2 / CO ratio of 5.1, and a flow rate of 291505 Nm³. 3 / h, air pressure 0.4MPa, temperature 950℃. The metallization rate of sponge iron is ≥93%, and the carbon content is 1.3%.

[0188] Example 3

[0189] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 1 The system shown will proceed as follows:

[0190] (1) Coke oven gas treatment process

[0191] like Figure 1 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0192] The volume of coke oven gas is 171043 Nm³. 3 The gas flow rate is 81000 Nm³ / h, the temperature is 40℃, and the pressure after pressurization is 0.55 MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 81000 Nm³ / h. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0193] (2) Blast furnace low-carbon smelting process

[0194] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 90043 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment is applied, with an oxygen enrichment rate of 44%. This reduces the coke ratio in the blast furnace by 68 kg / tHM and reduces CO2 emissions by 18.1%.

[0195] (3) Converter gas treatment process

[0196] The purified converter gas is pressurized and decarburized to obtain a second decarburized gas and a second desorbed gas. The second decarburized gas is heated and used as part of the reducing gas, while the second desorbed gas is supplied to the steel plant's gas pipeline network. The decarburization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0197] The converter gas volume is 51384 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of the second decarbonization gas is 1.17 times that of the converter gas, and the gas volume is 40500 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the second desorption gas is 38% of that of the converter gas, and the gas volume is 10884Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0198] (4) Hydrogen-based vertical furnace top gas circulation process

[0199] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0200] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 52.6%, the CO content is 7.3%, and the gas volume is 289212 Nm³. 3 / h, gas pressure 0.26MPa, temperature 466℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonization and denitrification gas and cooling water, resulting in a temperature reduction to ≤40℃. 14.2% of the top gas after heat exchange is used as fuel gas for heating reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonization and denitrification gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 371℃ for the third decarbonization and denitrification gas.

[0201] The calorific value of the third decarbonization and denitrification gas is 1.38 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 160173 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 79.2% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 35346Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0202] (5) Hydrogen-based shaft furnace smelting process

[0203] Hydrogen, the second decarburization gas, and the third decarburization and denitrification gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas used for heating with the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0204] The reducing gas has a hydrogen content of 73.2%, an H2 / CO ratio of 7.2, and a flow rate of 286,135 Nm³. 3 / h, air pressure 0.4MPa, temperature 950℃. The metallization rate of sponge iron is ≥93%, and the carbon content is 0.7%.

[0205] Example 4

[0206] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 1 The system shown will proceed as follows:

[0207] (1) Coke oven gas treatment process

[0208] like Figure 1 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0209] The volume of coke oven gas is 186,880 Nm³. 3 The gas flow rate is 88500 Nm³ / h, the temperature is 40℃, and the pressure after pressurization is 0.55 MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 88500 Nm³ / h. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0210] (2) Blast furnace low-carbon smelting process

[0211] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 98380 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment is applied, with an oxygen enrichment rate of 52%. This reduces the coke ratio in the blast furnace by 73 kg / tHM and reduces CO2 emissions by 19.5%.

[0212] (3) Converter gas treatment process

[0213] The purified converter gas is pressurized and decarburized to obtain a second decarburized gas and a second desorbed gas. The second decarburized gas is heated and used as part of the reducing gas, while the second desorbed gas is supplied to the steel plant's gas pipeline network. The decarburization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0214] The converter gas volume is 24740 Nm³. 3 The gas flow rate is 19500 Nm³ / h, the temperature is 40℃, and the pressurized gas pressure is 0.55 MPa. The calorific value of the second decarburization gas is 1.17 times that of the converter gas, and the gas volume is 19500 Nm³ / h. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the second desorption gas is 38% of that of the converter gas, and the gas volume is 5240Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0215] (4) Hydrogen-based vertical furnace top gas circulation process

[0216] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0217] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 63.2%, the CO content is 3.7%, and the gas volume is 287,905 Nm³. 3 / h, gas pressure 0.26MPa, temperature 447℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonization and denitrification gas and cooling water, resulting in a temperature reduction to ≤40℃. 13.1% of the top gas after heat exchange is used as fuel gas for heating reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonization and denitrification gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 352℃ for the third decarbonization and denitrification gas.

[0218] The calorific value of the third decarbonization and denitrification gas is 1.37 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 172011 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 74.3% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 20480Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0219] (5) Hydrogen-based shaft furnace smelting process

[0220] Hydrogen, the second decarburization gas, and the third decarburization and denitrification gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas used for heating with the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0221] The reducing gas has a hydrogen content of 85.6%, an H2 / CO ratio of 17.3, and a flow rate of 284,559 Nm³. 3 / h, air pressure 0.4MPa, temperature 950℃. The metallization rate of the sponge iron is ≥93%, and the carbon content is 0.3%.

[0222] Example 5

[0223] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 1 The system shown will proceed as follows:

[0224] (1) Coke oven gas treatment process

[0225] like Figure 1 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0226] The volume of coke oven gas is 195,960 Nm³. 3 The gas flow rate is 92800 Nm³ / h, the temperature is 40℃, and the pressure after pressurization is 0.55 MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 92800 Nm³ / h. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0227] (2) Blast furnace low-carbon smelting process

[0228] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 103160 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment is applied, with an oxygen enrichment rate of 57%. This reduces the coke ratio in the blast furnace by 76 kg / tHM and decreases CO2 emissions by 20.3%.

[0229] (3) Converter gas treatment process

[0230] The purified converter gas is pressurized and decarburized to obtain a second decarburized gas and a second desorbed gas. The second decarburized gas is heated and used as part of the reducing gas, while the second desorbed gas is supplied to the steel plant's gas pipeline network. The decarburization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0231] The converter gas volume is 7232 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of the second decarbonization gas is 1.17 times that of the converter gas, and the gas volume is 5700 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the second desorbed gas is 38% of that of the converter gas, and the gas volume is 1532Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0232] (4) Hydrogen-based vertical furnace top gas circulation process

[0233] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0234] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 71.8%, the CO content is 1.1%, and the gas volume is 282312 Nm³. 3 / h, gas pressure 0.26MPa, temperature 426℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonization and denitrification gas and cooling water, resulting in a temperature reduction to ≤40℃. 12.3% of the top gas after heat exchange is used as fuel gas for heating reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonization and denitrification gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 331℃ for the third decarbonization and denitrification gas.

[0235] The calorific value of the third decarbonization and denitrification gas is 1.33 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 181078 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 70.3% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 10461Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0236] (5) Hydrogen-based shaft furnace smelting process

[0237] Hydrogen, the second decarburization gas, and the third decarburization and denitrification gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas used for heating with the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0238] The reducing gas has a hydrogen content of 95.5%, an H2 / CO ratio of 64.3, and a flow rate of 279,736 Nm³. 3 / h, air pressure 0.4MPa, temperature 950℃. The metallization rate of sponge iron is ≥93%, and the carbon content is 0.2%.

[0239] Example 6

[0240] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 1 The system shown will proceed as follows:

[0241] (1) Coke oven gas treatment process

[0242] like Figure 1 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0243] The volume of coke oven gas is 140424 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 66500 Nm³. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0244] (2) Blast furnace low-carbon smelting process

[0245] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 73924 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment is applied, with an oxygen enrichment rate of 31%. This reduces the coke ratio in the blast furnace by 48 kg / tHM and decreases CO2 emissions by 12.8%.

[0246] (3) Converter gas treatment process

[0247] The purified converter gas is pressurized and decarburized to obtain a second decarburized gas and a second desorbed gas. The second decarburized gas is heated and used as part of the reducing gas, while the second desorbed gas is supplied to the steel plant's gas pipeline network. The decarburization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0248] The converter gas volume is 93252 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of the second decarbonization gas is 1.17 times that of the converter gas, and the gas volume is 73500 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the second desorbed gas is 38% of that of the converter gas, and the gas volume is 19752Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0249] (4) Hydrogen-based vertical furnace top gas circulation process

[0250] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0251] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 38.3%, the CO content is 12.1%, and the gas volume is 301,836 Nm³. 3 / h, gas pressure 0.26MPa, temperature 512℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonized and denitrified gas and cooling water, resulting in a temperature reduction to ≤40℃. 13.7% of the top gas after heat exchange is used as fuel gas for heating reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonized and denitrified gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 417℃ for the third decarbonized and denitrified gas.

[0252] The calorific value of the third decarbonization and denitrification gas is 1.35 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 154,468 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 87.6% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 54086Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0253] (5) Hydrogen-based shaft furnace smelting process

[0254] Hydrogen, the second decarburization gas, and the third decarburization and denitrification gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas heated by the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 15%, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 85%.

[0255] The reducing gas has a hydrogen content of 55.2%, an H2 / CO ratio of 3.2, and a flow rate of 299317 Nm³. 3 / h, air pressure 0.4MPa, temperature 950℃. The metallization rate of sponge iron is ≥93%, and the carbon content is 1.8%.

[0256] Example 7

[0257] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 1 The system shown will proceed as follows:

[0258] (1) Coke oven gas treatment process

[0259] like Figure 1 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0260] The volume of coke oven gas is 137679 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 65200 Nm³. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0261] (2) Blast furnace low-carbon smelting process

[0262] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 72479 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment (30%) is applied. This reduces the coke ratio in the blast furnace by 45 kg / tHM and decreases CO2 emissions by 12.0%.

[0263] (3) Converter gas treatment process

[0264] The purified converter gas is pressurized and decarburized to obtain a second decarburized gas and a second desorbed gas. The second decarburized gas is heated and used as part of the reducing gas, while the second desorbed gas is supplied to the steel plant's gas pipeline network. The decarburization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0265] The converter gas volume is 93252 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of the second decarburization gas is 1.25 times that of the converter gas, and the gas volume is 73500 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the second desorption gas is 35% of that of the converter gas, and the gas volume is 19752Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0266] (4) Hydrogen-based vertical furnace top gas circulation process

[0267] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0268] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 38.2%, the CO content is 12.1%, and the gas volume is 305108 Nm³. 3 / h, gas pressure 0.26MPa, temperature 514℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonized and denitrified gas and cooling water, resulting in a temperature reduction to ≤40℃. 12.4% of the top gas after heat exchange is used as fuel gas for heating reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonized and denitrified gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 419℃ for the third decarbonized and denitrified gas.

[0269] The calorific value of the third decarbonization and denitrification gas is 1.34 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 158906 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 87.5% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 51155Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0270] (5) Hydrogen-based shaft furnace smelting process

[0271] Hydrogen, the second decarburization gas, and the third decarburization and denitrification gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas heated by the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 25%, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 75%.

[0272] The reducing gas has a hydrogen content of 55.2%, an H2 / CO ratio of 3.2, and a flow rate of 301185 Nm³. 3 / h, air pressure 0.4MPa, temperature 950℃. The metallization rate of sponge iron is ≥93%, and the carbon content is 1.6%.

[0273] Example 8

[0274] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 1 The system shown will proceed as follows:

[0275] (1) Coke oven gas treatment process

[0276] like Figure 1 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0277] The volume of coke oven gas is 153094 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.45MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 72500 Nm³. 3 / h, air pressure 0.4MPa, temperature after heating 1050℃.

[0278] (2) Blast furnace low-carbon smelting process

[0279] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 80594 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.3MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment (30%) is applied. This reduces the coke ratio in the blast furnace by 45 kg / tHM and decreases CO2 emissions by 12.0%.

[0280] (3) Converter gas treatment process

[0281] The purified converter gas is pressurized and decarburized to obtain a second decarburized gas and a second desorbed gas. The second decarburized gas is heated and used as part of the reducing gas, while the second desorbed gas is supplied to the steel plant's gas pipeline network. The decarburization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0282] The converter gas volume is 100230 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.45MPa. The calorific value of the second decarbonization gas is 1.05 times that of the converter gas, and the gas volume is 79000 Nm³. 3 / h, gas pressure 0.4MPa, temperature after heating 1050℃. The calorific value of the second desorption gas is 40% of that of the converter gas, and the gas volume is 21230Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0283] (4) Hydrogen-based vertical furnace top gas circulation process

[0284] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0285] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 40.1%, the CO content is 12.7%, and the gas volume is 318,767 Nm³. 3 / h, gas pressure 0.16MPa, temperature 534℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical furnace undergoes two stages of heat exchange with the third decarbonized and denitrified gas and cooling water, resulting in a temperature reduction to ≤40℃. 17.1% of the top gas after heat exchange is used as fuel gas to heat the reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.45MPa. The third decarbonized and denitrified gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical furnace, resulting in a temperature increase of 439℃.

[0286] The calorific value of the third decarbonization and denitrification gas is 1.32 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 159,740 Nm³. 3 / h, gas pressure 0.4MPa, further heated to 1050℃. The calorific value of the third desorbed gas is 88.3% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 60510Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0287] (5) Hydrogen-based shaft furnace smelting process

[0288] Hydrogen, the second decarburization gas, and the third decarburization and denitrification gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas used for heating with the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0289] The reducing gas has a hydrogen content of 55.8%, an H2 / CO ratio of 3.2, and a flow rate of 317,686 Nm³. 3 / h, air pressure 0.3MPa, temperature 1050℃. The metallization rate of the sponge iron is ≥95%, and the carbon content is 1.9%.

[0290] Example 9

[0291] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 2 The system shown will proceed as follows:

[0292] (1) Coke oven gas treatment process

[0293] like Figure 2 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0294] The volume of coke oven gas is 69684 Nm³. 3 The gas flow rate is 33000 Nm³ / h, the temperature is 40℃, and the pressure after pressurization is 0.55 MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 33000 Nm³ / h. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0295] (2) Blast furnace low-carbon smelting process

[0296] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 36684 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment is applied at a rate of 14%. This reduces the coke ratio in the blast furnace by 25 kg / tHM and decreases CO2 emissions by 6.7%.

[0297] (3) FINEX gas treatment process

[0298] A portion of the FINEX gas undergoes wet dust removal, pressurization, and decarbonization to obtain first decarbonized gas and first desorbed gas. The first decarbonized gas is heated and used as part of the reducing gas, while the first desorbed gas is sent to the steelmaking workshop for CO2 steelmaking. The decarbonization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0299] The volume of FINEX gas is 83881 Nm³. 3 / h, dust content after coarse dust removal ≤6g / Nm 3 After wet dust removal, the dust content is ≤5mg / Nm³. 3The temperature was 40℃, and the pressurized gas pressure was 0.55MPa. The calorific value of the first decarbonized gas was 1.5 times that of Finex gas, and the gas volume was 56200 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the first desorbed gas is 17.9% of the calorific value of FINEX gas, and the gas volume is 27681Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0300] (4) Hydrogen-based vertical furnace top gas circulation process

[0301] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0302] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 39.7%, the CO content is 26.5%, and the gas volume is 248043 Nm³. 3 / h, gas pressure 0.26MPa, temperature 485℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonization and denitrification gas and cooling water, resulting in a temperature reduction to ≤40℃. 17.9% of the top gas after heat exchange is used as fuel gas to heat the reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonization and denitrification gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 390℃ for the third decarbonization and denitrification gas.

[0303] The calorific value of the third decarbonization and denitrification gas is 1.40 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 149593 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 32.5% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 32684Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0304] (5) Hydrogen-based shaft furnace smelting process

[0305] Hydrogen, the third decarbonization and denitrification gas, and the first decarbonization gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas heated by the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0306] The reducing gas has a hydrogen content of 55.1%, an H2 / CO ratio of 1.47, and a flow rate of 243,550 Nm³. 3 / h, air pressure 0.4MPa, temperature 950℃. The metallization rate of sponge iron is ≥93%, and the carbon content is 3.5%.

[0307] Example 10

[0308] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 2 The system shown will proceed as follows:

[0309] (1) Coke oven gas treatment process

[0310] like Figure 2 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0311] The volume of coke oven gas is 195115 Nm³. 3 The gas flow rate is 92400 Nm³ / h, the temperature is 40℃, and the pressure after pressurization is 0.55 MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 92400 Nm³ / h. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0312] (2) Blast furnace low-carbon smelting process

[0313] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 102715 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment is applied, with an oxygen enrichment rate of 58%. This reduces the coke ratio in the blast furnace by 78 kg / tHM and reduces CO2 emissions by 20.8%.

[0314] (3) FINEX gas treatment process

[0315] A portion of the FINEX gas undergoes wet dust removal, pressurization, and decarbonization to obtain first decarbonized gas and first desorbed gas. The first decarbonized gas is heated and used as part of the reducing gas, while the first desorbed gas is sent to the steelmaking workshop for CO2 steelmaking. The decarbonization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0316] The volume of FINEX gas is 2985 Nm³. 3 / h, dust content after coarse dust removal ≤6g / Nm 3 After wet dust removal, the dust content is ≤5mg / Nm³. 3 The temperature was 40℃, and the pressurized gas pressure was 0.55MPa. The calorific value of the first decarbonized gas was 1.45 times that of Finex gas, and the gas volume was 2000 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the first desorbed gas is 18% of the calorific value of FINEX gas, and the gas volume is 985Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0317] (4) Hydrogen-based vertical furnace top gas circulation process

[0318] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0319] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 70.2%, the CO content is 1.0%, and the gas volume is 276415 Nm³. 3 / h, gas pressure 0.26MPa, temperature 418℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonization and denitrification gas and cooling water, resulting in a temperature reduction to ≤40℃. 3.5% of the top gas after heat exchange is used as fuel gas for heating reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonization and denitrification gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 323℃ for the third decarbonization and denitrification gas.

[0320] The calorific value of the third decarbonization and denitrification gas is 1.36 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 173,971 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 71.9% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 6249Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0321] (5) Hydrogen-based shaft furnace smelting process

[0322] Hydrogen, the third decarbonization and denitrification gas, and the first decarbonization gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas heated by the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0323] The reducing gas has a hydrogen content of 94.6%, an H2 / CO ratio of 75, and a flow rate of 273,320 Nm³. 3 / h, air pressure 0.4MPa, temperature 950℃. The metallization rate of sponge iron is ≥93%, and the carbon content is 0.2%.

[0324] Example 11

[0325] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 2 The system shown will proceed as follows:

[0326] (1) Coke oven gas treatment process

[0327] like Figure 2 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0328] The volume of coke oven gas is 84466 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of hydrogen is 70% of that of coke oven gas, and the gas volume is 40000 Nm³. 3 / h, air pressure 0.5MPa, temperature after heating 1050℃.

[0329] (2) Blast furnace low-carbon smelting process

[0330] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.15 times that of the coke oven gas, and the gas volume is 44466 Nm³. 3The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment (30%) is applied. This reduces the coke ratio in the blast furnace by 30 kg / tHM and decreases CO2 emissions by 8%.

[0331] (3) FINEX gas treatment process

[0332] A portion of the FINEX gas undergoes wet dust removal, pressurization, and decarbonization to obtain first decarbonized gas and first desorbed gas. The first decarbonized gas is heated and used as part of the reducing gas, while the first desorbed gas is sent to the steelmaking workshop for CO2 steelmaking. The decarbonization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0333] The volume of FINEX gas is 81940 Nm³. 3 / h, dust content after coarse dust removal ≤6g / Nm 3 After wet dust removal, the dust content is ≤5mg / Nm³. 3 The temperature was 40℃, and the pressurized gas pressure was 0.55 MPa. The calorific value of the first decarbonized gas was 1.55 times that of Finex gas, and the gas volume was 54900 Nm³. 3 / h, gas pressure 0.5MPa, temperature after heating 1050℃. The calorific value of the first desorbed gas is 17% of the calorific value of FINEX gas, and the gas volume is 27040Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0334] (4) Hydrogen-based vertical furnace top gas circulation process

[0335] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0336] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 43.6%, the CO content is 25.1%, and the gas volume is 268,191 Nm³. 3 / h, gas pressure 0.26MPa, temperature 504℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonized and denitrified gas and cooling water, resulting in a temperature reduction to ≤40℃. 15.9% of the top gas after heat exchange is used as fuel gas for heating reducing gases. The remaining portion of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonized and denitrified gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 411℃.

[0337] The calorific value of the third decarbonization and denitrification gas is 1.36 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 163,771 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 1050℃. The calorific value of the third desorbed gas is 34.7% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 30950Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0338] (5) Hydrogen-based shaft furnace smelting process

[0339] Hydrogen, the third decarbonization and denitrification gas, and the first decarbonization gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas heated by the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0340] The reducing gas has a hydrogen content of 58.8%, an H2 / CO ratio of 1.7, and a flow rate of 264,147 Nm³. 3 / h, air pressure 0.4MPa, temperature 1050℃. The metallization rate of the sponge iron is ≥95%, and the carbon content is 0.2%.

[0341] Example 12

[0342] This embodiment of the steel plant secondary energy recovery and utilization and hydrogen metallurgy method adopts... Figure 3 The system shown will proceed as follows:

[0343] (1) Coke oven gas treatment process

[0344] like Figure 3 As shown, purified coke oven gas is pressurized and hydrogen-extracted to obtain hydrogen and a fourth desorbed gas. The hydrogen is heated and used as part of the reducing gas, while the fourth desorbed gas is pressurized and injected into the blast furnace through a tuyer for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption methods.

[0345] The volume of coke oven gas is 117196 Nm³. 3The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of hydrogen is 65% of that of coke oven gas, and the gas volume is 55500 Nm³. 3 / h, air pressure 0.5MPa, temperature after heating 950℃.

[0346] (2) Blast furnace low-carbon smelting process

[0347] The calorific value of the fourth desorption gas supplied to the blast furnace is 1.3 times that of the coke oven gas, and the gas volume is 61696 Nm³. 3 The gas is heated at 40℃ and pressurized to 0.4MPa per hour. The pressurized fourth desorbed gas is injected into the blast furnace through the tuyeres for low-carbon smelting. Simultaneously, oxygen enrichment (25%) is applied. This reduces the coke ratio in the blast furnace by 45 kg / tHM and decreases CO2 emissions by 12.0%.

[0348] (3) Converter gas treatment process

[0349] The purified converter gas is pressurized and decarburized to obtain a second decarburized gas and a second desorbed gas. The second decarburized gas is heated and used as part of the reducing gas, while the second desorbed gas is supplied to the steel plant's gas pipeline network. The decarburization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0350] The converter gas volume is 65974 Nm³. 3 The gas flow rate is 40℃, and the pressurized gas pressure is 0.55MPa. The calorific value of the second decarbonization gas is 1.17 times that of the converter gas, and the gas volume is 52000 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the second desorption gas is 38% of that of the converter gas, and the gas volume is 13974Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0351] (4) FINEX gas treatment process

[0352] A portion of the FINEX gas undergoes wet dust removal, pressurization, and decarbonization to obtain first decarbonized gas and first desorbed gas. The first decarbonized gas is heated and used as part of the reducing gas, while the first desorbed gas is sent to the steelmaking workshop for CO2 steelmaking. The decarbonization method can be any one or more of physical absorption, chemical absorption, or physical-chemical absorption.

[0353] The volume of FINEX gas is 39104 Nm³. 3 / h, dust content after coarse dust removal ≤6g / Nm 3 After wet dust removal, the dust content is ≤5mg / Nm³. 3The temperature was 40℃, and the pressurized gas pressure was 0.55MPa. The calorific value of the first decarbonized gas was 1.5 times that of Finex gas, and the gas volume was 26200 Nm³. 3 / h, gas pressure 0.5MPa, heated to 950℃. The calorific value of the first desorbed gas is 17.9% of the calorific value of FINEX gas, and the gas volume is 12904 Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0354] (5) Hydrogen-based vertical furnace top gas circulation process

[0355] After the top gas from the hydrogen-based vertical shaft furnace undergoes dust removal, heat exchange, pressurization, and decarbonization and denitrification, it yields third decarbonized and denitrified gas and third desorbed gas. The third decarbonized and denitrified gas is heated and used as part of the reducing gas. Part of the third desorbed gas is used as fuel gas for heating the reducing gas, and the other part is transported to the steel plant's gas pipeline network. The decarbonization and denitrification methods can be any one or more of physical absorption, chemical absorption, and physical-chemical absorption methods.

[0356] The hydrogen content of the top gas from the hydrogen-based vertical shaft furnace is 38.5%, the CO content is 14.8%, and the gas volume is 273076 Nm³. 3 / h, gas pressure 0.26MPa, temperature 487℃; dust content of the top gas from the hydrogen-based vertical shaft furnace after coarse dust removal ≤6g / Nm³ 3 The dust content of the top gas from the hydrogen-based vertical furnace after dry dust removal is ≤5mg / Nm³. 3 The top gas of the hydrogen-based vertical shaft furnace undergoes two stages of heat exchange with the third decarbonization and denitrification gas and cooling water, resulting in a temperature reduction to ≤40℃. 30.5% of the top gas after heat exchange is used as fuel gas to heat the reducing gases. The remaining part of the top gas after heat exchange is pressurized to a pressure of 0.55MPa. The third decarbonization and denitrification gas undergoes a first-stage heat exchange with the dust-removed top gas of the hydrogen-based vertical shaft furnace, resulting in a temperature increase of 392℃ for the third decarbonization and denitrification gas.

[0357] The calorific value of the third decarbonization and denitrification gas is 1.35 times that of the top gas from the hydrogen-based vertical shaft furnace, and the gas volume is 131908 Nm³. 3 / h, gas pressure 0.5MPa, further heated to 950℃. The calorific value of the third desorbed gas is 77.3% of the calorific value of the top gas of the hydrogen-based vertical shaft furnace, and the gas volume is 58065Nm³. 3 / h, temperature 40℃, air pressure 0.02MPa.

[0358] (6) Hydrogen-based shaft furnace smelting process

[0359] Hydrogen, the second decarburization gas, the third decarburization and denitrification gas, and the first decarburization gas are mixed and heated to become the reducing gas of the hydrogen-based vertical shaft furnace, producing qualified sponge iron. The fuel gas used for heating with the reducing gas is the third desorption gas and the top gas of the hydrogen-based vertical shaft furnace after heat exchange. The volume fraction of the third desorption gas is 0, and the volume fraction of the top gas of the hydrogen-based vertical shaft furnace after heat exchange is 100%.

[0360] The reducing gas has a hydrogen content of 55.7%, an H2 / CO ratio of 2.6, and a flow rate of 271,761 Nm³. 3 The temperature was 950℃, the pressure was 0.4 MPa, and the metallization rate of the sponge iron was ≥93%, with a carbon content of 3.1%.

[0361] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for secondary energy recovery and utilization in steel plants and hydrogen metallurgy, characterized in that, include: Obtain by-product coal gas from steel plants, separate the reducing gas, and introduce it into a hydrogen-based vertical shaft furnace to produce sponge iron. The top coal gas discharged from the top of the hydrogen-based vertical shaft furnace is recycled. The by-product gas from the steel plant includes FINEX gas, converter gas, hydrogen-based vertical shaft furnace top gas, and coke oven gas; or, the by-product gas from the steel plant includes FINEX gas, hydrogen-based vertical shaft furnace top gas, and coke oven gas. The reducing gas includes a first decarbonization gas, a second decarbonization gas, a third decarbonization and denitrification gas, and hydrogen; or, the reducing gas includes a first decarbonization gas, a third decarbonization and denitrification gas, and hydrogen. The first decarbonized gas is obtained by separating the FINEX gas through decarbonization treatment; the second decarbonized gas is obtained by separating the converter gas through decarbonization treatment; the third decarbonized and denitrified gas is obtained by separating the hydrogen-based vertical shaft furnace top gas through decarbonization and denitrification treatment; and the hydrogen is obtained by separating the coke oven gas through hydrogen extraction treatment. The coke oven gas is separated into hydrogen and a fourth desorbed gas after hydrogen extraction treatment. The fourth desorbed gas is injected into the blast furnace for low-carbon smelting to produce liquid iron. The method also includes the following operations ① to ④: ① The FINEX gas is decarbonized and separated to obtain the first decarbonized gas and the first desorbed gas. The first desorbed gas is transported to the steelmaking workshop for CO2 steelmaking. ②The converter gas is decarbonized and separated to obtain the second decarbonized gas and the second desorbed gas, and the second desorbed gas is transported to the steel plant gas pipeline network; ③ A portion of the hydrogen-based vertical furnace top gas is separated by decarbonization and denitrification to obtain the third decarbonized and denitrified gas, and another portion of the hydrogen-based vertical furnace top gas is used as the first fuel gas to heat the reducing gas; ④ A portion of the hydrogen-based vertical furnace top gas is decarbonized and denitrified to obtain the third decarbonized and denitrified gas and the third desorbed gas. A portion of the third desorbed gas is used as the second fuel gas to heat the reducing gas.

2. The method according to claim 1, characterized in that, Operation ③ further includes: in the hydrogen-based vertical furnace top gas, the volume fraction of the other portion of the hydrogen-based vertical furnace top gas used as the first fuel gas is 3.5~30.5%; And / or, operation ④ further includes: another portion of the third desorbed gas being delivered to the steel plant's gas pipeline network; And / or, when the method further includes operations ③ and ④, the volume ratio of the first fuel gas to the second fuel gas is ≥3.

3. The method according to claim 1, characterized in that, The method further includes a pretreatment process, which includes at least one of purification, dust removal, pressurization, and heat exchange treatment. The purification process is selected from at least one of the following operations ⑤ to ⑥: ⑤ The converter gas was purified before undergoing decarbonization treatment; ⑥ The coke oven gas was purified before being subjected to hydrogen extraction treatment; The dust removal process is selected from at least one of the following operations ⑦ to ⑧: ⑦ The FINEX gas underwent dust removal treatment before being decarbonized. ⑧ The hydrogen-based vertical furnace top gas was subjected to dust removal treatment before being decarbonized and denitrified, and before being used as the first fuel gas; The pressurization process is selected from the following operations ⑨ to At least one of the following: ⑨ The FINEX gas was pressurized before undergoing decarbonization treatment; ⑩ The converter gas was pressurized before undergoing decarbonization treatment; The top gas from the hydrogen-based vertical furnace was pressurized before undergoing decarbonization and denitrification treatment; The coke oven gas was pressurized before undergoing hydrogen extraction. Before the fourth desorbed gas is injected into the blast furnace, it is also pressurized. The heat exchange treatment method includes: the top gas of the hydrogen-based vertical furnace undergoes heat exchange treatment before being decarbonized and denitrified, and before being used as the first fuel gas.

4. The method according to claim 3, characterized in that: The heat exchange treatment method includes: reducing the temperature of the top gas of the hydrogen-based vertical furnace to 40°C or below through heat exchange.

5. The method according to claim 3, characterized in that: The heat exchange treatment method is heat exchange, which includes multi-stage heat exchange, including primary heat exchange and secondary heat exchange. The primary heat exchange method includes: exchanging heat between the hydrogen-based vertical furnace top gas and the third decarbonized and denitrified gas. The secondary heat exchange method includes: exchanging heat between the hydrogen-based vertical furnace top gas after primary heat exchange and the coolant.

6. The method according to claim 1, characterized in that: The reducing gas, after being heated, is introduced into a hydrogen-based vertical furnace to produce sponge iron.

7. The method according to claim 1, characterized in that: The reducing gas has a hydrogen content of 55-95.5% and an H2 / CO ratio ≥ 1.

4. When the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the amount of reducing gas introduced is 243,550-317,000 Nm³. 3 At a pressure of 0.3~0.4MPa and a temperature of 950~1050℃, the metallization rate of the produced sponge iron is 93~95%, and the carbon content is 0.2~3.5%.

8. The method according to claim 7, characterized in that: When the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the flow rate of the FINEX gas is 2980~83800 Nm³. 3 / h, temperature 20~50℃; at this time, the calorific value of the first decarbonized gas obtained by the decarbonization treatment of the FINEX gas is 1.45~1.55 times that of the FINEX gas, and the gas volume is 2000~56200 Nm³. 3 / h, gas pressure 0.4~0.5MPa, temperature after heating 950~1050℃; When the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the converter gas flow rate is 7200~100000 Nm³. 3 / h, temperature 20~50℃; at this time, the calorific value of the second decarbonized gas obtained by decarbonization treatment of the converter gas is 1.05~1.25 times that of the converter gas, and the gas volume is 5700~79000 Nm³. 3 / h, gas pressure 0.4~0.5MPa, temperature after heating 950~1050℃; When the hydrogen-based vertical shaft furnace produces 1 million tons of sponge iron per year, the hydrogen content of the top gas from the furnace is 38-72%, the CO content is 1-26.5%, and the gas volume is 248,000-319,000 Nm³. 3 / h, gas pressure 0.16~0.26MPa, temperature 418~534℃; at this time, the calorific value of the third decarbonized and denitrified gas obtained by separating a portion of the hydrogen-based vertical furnace top gas after decarbonization and denitrification treatment is 1.32~1.40 times that of a portion of the hydrogen-based vertical furnace top gas, and the gas volume is 131000~181000 Nm³. 3 / h, gas pressure 0.4~0.5MPa, temperature after heating 950~1050℃; When the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the coke oven gas volume is 69,600~196,000 Nm³. 3 The gas flow rate is 20~50℃, and the pressurized gas pressure is 0.45~0.55MPa. At this time, the hydrogen obtained from the coke oven gas after hydrogen extraction has a calorific value of 60~70% of the calorific value of the coke oven gas, and the gas flow rate is 33000~93000 Nm³. 3 / h, air pressure 0.4~0.5MPa, temperature after heating 950~1050℃.

9. The method according to claim 8, characterized in that: When the hydrogen-based shaft furnace produces 1 million tons of sponge iron per year, the coke oven gas volume is 69,600~196,000 Nm³. 3 The gas flow rate is 20~50℃, and the pressurized gas pressure is 0.45~0.55MPa. At this time, the hydrogen obtained from the coke oven gas after hydrogen extraction has a calorific value of 60~70% of the calorific value of the coke oven gas, and the gas flow rate is 33000~93000 Nm³. 3 The gas flow rate is 0.4~0.5MPa, and the temperature after heating is 950~1050℃; the calorific value of the resulting fourth desorbed gas is 1.15~1.45 times that of the coke oven gas, and the gas volume is 36600~104000 Nm³. 3 / h, temperature 20~50℃; the fourth desorbed gas is pressurized and injected into the blast furnace through the tuyeres for low-carbon smelting. During injection, oxygen is enriched at the same time, with an oxygen enrichment rate of 14~58%. The coke ratio of the blast furnace is reduced by 25~78 kg / tHM, and CO2 emissions are reduced by 6.7~20.8%.

10. A secondary energy recovery and utilization system for steel plants and a hydrogen metallurgical system, characterized in that: The system includes a third gas processing unit, a fourth gas processing unit, a heating device, a hydrogen-based vertical shaft furnace and a blast furnace. The system also includes a first gas processing unit and a second gas processing unit, or the system further includes a first gas processing unit. The first gas processing unit is used to process FINEX gas and includes a first decarbonization device. The first decarbonization device is used to decarbonize the FINEX gas, separate the FINEX gas into a first decarbonized gas and a first desorbed gas, and is provided with a first decarbonized gas outlet end, which is connected to the heating device. The second gas treatment unit is used to treat converter gas and includes a second decarbonization device; the first decarbonization device is used to decarbonize the converter gas, divide the converter gas into a second decarbonized gas and a second desorbed gas, and is provided with a second decarbonized gas outlet end, which is connected to the heating device. The third gas treatment unit is used to treat the top gas of the hydrogen-based vertical furnace, including a third decarbonization and denitrification device; the third decarbonization and denitrification device is used to remove CO2 and N2 from the top gas of the hydrogen-based vertical furnace, divide the top gas of the hydrogen-based vertical furnace into third decarbonization and denitrification gas and third desorption gas, and is provided with a third decarbonization and denitrification gas outlet end, which is connected to the heating device; The fourth gas processing unit is used to process coke oven gas, including a fourth hydrogen extraction device; the fourth hydrogen extraction device is used to extract hydrogen from coke oven gas, divide the coke oven gas into hydrogen and a fourth desorbed gas, and is provided with a hydrogen outlet end and a fourth desorbed gas outlet end, the hydrogen outlet end being connected to the heating device. The heating device is used to heat the first decarburized gas, the second decarburized gas, the third decarburized and denitrified gas, and hydrogen; the heating device is provided with a reducing gas outlet end, which is connected to the hydrogen-based vertical furnace, and the hydrogen-based vertical furnace uses the reducing gas to produce sponge iron; The fourth desorption gas outlet is connected to the blast furnace, and the blast furnace uses the fourth desorption gas for low-carbon smelting to produce liquid iron. The system also includes the following equipment: gas pipeline network and steelmaking workshop; The first decarbonization device is also provided with a first desorption gas outlet end, which is connected to the steelmaking workshop to send the first desorption gas into the steelmaking workshop; The second decarbonization device is also provided with a second desorption gas outlet end, which is connected to the gas pipeline network to send the second desorption gas into the gas pipeline network; The third decarbonization and denitrification device is further provided with a third desorption gas outlet end, and the heating device is provided with a second fuel gas inlet end. The third desorption gas outlet end is connected to the second fuel gas inlet end so as to send the third desorption gas into the heating device as fuel gas for heating. The third desorbed gas outlet is also connected to the gas pipeline network to send the third desorbed gas into the gas pipeline network; The heating device is also provided with a first fuel gas inlet, which is the inlet for feeding hydrogen-based vertical furnace top gas into the heating device, so as to feed hydrogen-based vertical furnace top gas into the heating device as fuel gas for heating.

11. The system according to claim 10, characterized in that, The system further includes at least one of the following devices: a second purification device, a fourth purification device, a first dust removal device, a third dust removal device, a first pressurizer, a second pressurizer, a third pressurizer, a fourth pressurizer, a fifth pressurizer, and a heat exchange device; The second gas treatment unit also includes a second purification device, which is located before the second decarbonization device and is used to purify the converter gas. The fourth gas treatment unit also includes a fourth purification device, which is located before the fourth hydrogen extraction device and is used to purify the coke oven gas. The first gas treatment unit also includes a first dust removal device, which is located before the first decarbonization device and is used to remove dust from the FINEX gas. The third gas treatment unit also includes a third dust removal device, which is used to remove dust from the top gas of the hydrogen-based vertical furnace. The first gas treatment unit also includes a first compressor, which is used to pressurize the dust-removed FINEX gas; The second gas treatment unit also includes a second compressor, which is used to pressurize the purified converter gas; The third gas processing unit also includes a third compressor, which is used to pressurize the top gas of the hydrogen-based vertical furnace after heat exchange. The fourth gas processing unit also includes a fourth compressor, which is used to pressurize the coke oven gas; The fourth gas treatment unit also includes a fifth compressor, which is located between the fourth hydrogen extraction device and the blast furnace and is used to pressurize the fourth desorbed gas. The heat exchange device is used for heat exchange treatment of the top gas of the hydrogen-based vertical furnace.

12. The system according to claim 11, characterized in that: The heat exchange device includes a multi-stage heat exchanger, which includes a primary heat exchanger and a secondary heat exchanger connected in sequence. The primary heat exchanger is connected to the outlet of the third decarbonized and denitrified gas and is the site for heat exchange between the third decarbonized and denitrified gas and the top gas of the hydrogen-based vertical furnace. The secondary heat exchanger is the site for heat exchange between the coolant and the top gas of the hydrogen-based vertical furnace.

13. The application of the method according to any one of claims 1 to 9 or the system according to any one of claims 10 to 12 in the field of hydrogen metallurgy.

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