CN117947235A - Secondary energy recycling and hydrogen metallurgy method and system for steel mill and application of secondary energy recycling and hydrogen metallurgy method and system - Google Patents
Secondary energy recycling and hydrogen metallurgy method and system for steel mill and application of secondary energy recycling and hydrogen metallurgy method and system Download PDFInfo
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- CN117947235A CN117947235A CN202311801104.8A CN202311801104A CN117947235A CN 117947235 A CN117947235 A CN 117947235A CN 202311801104 A CN202311801104 A CN 202311801104A CN 117947235 A CN117947235 A CN 117947235A
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- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 614
- 239000001257 hydrogen Substances 0.000 title claims abstract description 597
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 580
- 238000000034 method Methods 0.000 title claims abstract description 271
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 76
- 239000010959 steel Substances 0.000 title claims abstract description 76
- 238000005272 metallurgy Methods 0.000 title claims abstract description 43
- 238000004064 recycling Methods 0.000 title claims abstract description 38
- 239000007789 gas Substances 0.000 claims abstract description 1708
- 238000005261 decarburization Methods 0.000 claims abstract description 316
- 238000003795 desorption Methods 0.000 claims abstract description 275
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 160
- 239000000571 coke Substances 0.000 claims abstract description 144
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 92
- 229910052742 iron Inorganic materials 0.000 claims abstract description 80
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 78
- 238000003723 Smelting Methods 0.000 claims abstract description 68
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 46
- 238000000605 extraction Methods 0.000 claims abstract description 34
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 24
- 150000002431 hydrogen Chemical class 0.000 claims abstract description 21
- 239000007788 liquid Substances 0.000 claims abstract description 10
- 239000006227 byproduct Substances 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims description 218
- 239000000428 dust Substances 0.000 claims description 180
- 239000002737 fuel gas Substances 0.000 claims description 98
- 238000005262 decarbonization Methods 0.000 claims description 45
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 34
- 229910052760 oxygen Inorganic materials 0.000 claims description 34
- 239000001301 oxygen Substances 0.000 claims description 34
- 238000009628 steelmaking Methods 0.000 claims description 34
- 238000007664 blowing Methods 0.000 claims description 26
- 238000000926 separation method Methods 0.000 claims description 24
- 238000001465 metallisation Methods 0.000 claims description 15
- 238000000746 purification Methods 0.000 claims description 15
- 239000000110 cooling liquid Substances 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000005265 energy consumption Methods 0.000 abstract description 5
- 238000010521 absorption reaction Methods 0.000 description 115
- 239000000126 substance Substances 0.000 description 76
- 239000000498 cooling water Substances 0.000 description 14
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 8
- 238000002407 reforming Methods 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 210000001015 abdomen Anatomy 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000006477 desulfuration reaction Methods 0.000 description 2
- 230000023556 desulfurization Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000284 extract Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 230000000153 supplemental effect Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005255 carburizing Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000001833 catalytic reforming Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 125000001741 organic sulfur group Chemical group 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0073—Selection or treatment of the reducing gases
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
- C21B5/001—Injecting additional fuel or reducing agents
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
- C21B5/06—Making pig-iron in the blast furnace using top gas in the blast furnace process
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
- C21B5/001—Injecting additional fuel or reducing agents
- C21B2005/005—Selection or treatment of the reducing gases
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
Abstract
The invention discloses a steel mill secondary energy recycling and hydrogen metallurgy method, a system and application thereof. The method comprises the following steps: obtaining byproduct gas of a steel mill, separating out reducing gas, and introducing a hydrogen-based shaft furnace to produce sponge iron; the reducing gas comprises a first decarbonizing gas, a second decarbonizing gas, a third decarbonizing and nitrogen removing gas and hydrogen, or comprises the first decarbonizing gas, the third decarbonizing and nitrogen removing gas and hydrogen; the first decarburization gas is obtained by decarburization of FINEX gas, the second decarburization gas is obtained by decarburization of converter gas, the third decarburization and denitrification gas is obtained by decarburization and denitrification of hydrogen-based shaft furnace top gas, and the hydrogen is obtained by hydrogen extraction of coke oven gas; the coke oven gas is subjected to hydrogen extraction to obtain fourth desorption gas, and the fourth desorption gas is blown into a blast furnace for producing liquid molten iron by low-carbon smelting. The invention has important significance for reducing the primary energy consumption of the hydrogen-based shaft furnace and reducing the carbon emission of the shaft furnace by utilizing the secondary energy of the steel mill.
Description
Technical Field
The invention relates to the technical field of hydrogen metallurgy, in particular to a secondary energy recycling and hydrogen metallurgy method and system for a steel mill and application thereof.
Background
Hydrometallurgy is the realization of carbon reduction by "replacing carbon with hydrogen" during ore reduction. The hydrogen metallurgy process mainly comprises a hydrogen-rich blast furnace and a hydrogen-based shaft furnace. The hydrogen-rich blast furnace is characterized in that the blast furnace tuyere is used for blowing hydrogen-rich gas to replace partial CO reduction, so that carbon emission is reduced. The existing hydrogen-based shaft furnace reducing gas (H 2 and CO) mainly comes from natural gas catalytic reforming, and the domestic built Zhongjin CSDRI shaft furnace reducing gas comes from coke oven gas reforming, and all extra reformers and catalysts are needed. The Zhang Xuangao family shaft furnace uses zero reforming in a coke oven gas furnace, and needs higher temperature and pressure, thereby providing higher requirements for the shaft furnace.
Iron and steel enterprises generate a large amount of byproduct gas including coke oven gas, converter gas and the like every year. The coke oven gas contains more than 50% of H 2 and 20% of CH 4, and can be used as the blowing gas for hydrogen metallurgy. The converter gas contains more than 50% of CO, and can be used as supplementary gas for hydrogen metallurgy, so that the reduction heat consumption of H 2 is compensated and the carburizing of sponge iron is increased. FINEX was successfully used in korea as a non-blast furnace smelting reduction process. The FINEX gas contains CO and H 2 (more than 60%), and the N 2 content is extremely low due to oxygen enrichment operation, and the decarbonized gas can be used as a supplementary gas for hydrogen metallurgy reduction.
If the reducing gas in the coke oven gas, the converter gas and the FINEX gas can be used for smelting the hydrogen-based shaft furnace, a large amount of secondary energy generated by a steel plant (especially the steel plant with the FINEX device) is recycled, and the equipment investment of a conversion reforming link required for preparing the reducing gas is reduced, so that the process flow of the hydrogen-based shaft furnace is simplified. In addition, if methane in the coke oven gas can be sprayed into the blast furnace for smelting, the fuel ratio of the blast furnace can be reduced, and the carbon emission can be reduced.
Therefore, it is necessary to develop a method and a system for recycling secondary energy of a steel mill and hydrogen metallurgy, which provide important technical support for recycling secondary energy of the steel mill, reducing primary energy consumption of a hydrogen-based shaft furnace and reducing carbon emission of an iron-making process.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, the present invention aims to provide a secondary energy recycling and hydrogen metallurgy method for a steel mill, which reduces equipment investment in a reforming process required for preparing a reducing gas, reduces carbon emissions of a hydrogen-based shaft furnace and a hydrogen-rich blast furnace, and also provides a hydrogen metallurgy system without conversion, efficient reduction and carburization.
To achieve the above and other related objects, a first aspect of the present invention provides a steel mill secondary energy recycling and hydrogen metallurgy method, comprising:
obtaining byproduct gas of a steel mill, separating out reducing gas, introducing the reducing gas into a hydrogen-based shaft furnace to produce sponge iron, and recycling hydrogen-based shaft furnace top gas discharged from the top of the hydrogen-based shaft furnace;
The byproduct gas of the steel plant comprises FINEX gas, converter gas, hydrogen-based shaft furnace top gas and coke oven gas;
the reducing gas comprises a first decarburization gas, a second decarburization gas, a third decarburization and dephosphorization gas and hydrogen, or the reducing gas comprises a first decarburization gas, a third decarburization and dephosphorization gas and hydrogen;
The first decarburization gas is separated from the FINEX gas through decarburization treatment, the second decarburization gas is separated from the converter gas through decarburization treatment, the third decarburization and nitrogen removal gas is obtained from the hydrogen-based shaft furnace top gas through decarburization and denitrification treatment, and the hydrogen is separated from the coke oven gas through hydrogen extraction treatment;
And the coke oven gas is subjected to hydrogen extraction treatment and separation to obtain the hydrogen and fourth desorption gas, and the fourth desorption gas is blown into a blast furnace for producing liquid molten iron by low-carbon smelting. Further, the FINEX gas is subjected to decarburization and separation to obtain the first decarburization gas and a first desorption gas, and the first desorption gas is conveyed to a steelmaking plant for CO 2 steelmaking.
Further, the converter gas is subjected to decarburization and separation to obtain the second decarburization gas and a second desorption gas, and the second desorption gas is conveyed to a steel mill gas pipe network.
Further, the method further comprises: carrying out decarburization denitrification separation on one part of the hydrogen-based shaft furnace top gas to obtain third decarburization denitrification, and taking the other part of the hydrogen-based shaft furnace top gas as a first fuel gas to heat the reducing gas; preferably, the volume fraction of the other part of the hydrogen-based shaft furnace top gas used as the first fuel gas in the hydrogen-based shaft furnace top gas is 3.5-30.5%.
Further, a part of the hydrogen-based shaft furnace top gas is subjected to decarburization denitrification separation to obtain the third decarburization and denitrification gas and a third stripping gas, and a part of the third stripping gas is used as a second fuel gas for heating the reducing gas.
Further, the other part of the third desorption gas is conveyed to a steel mill gas pipe network.
Further, the volume and the dosage ratio of the first fuel gas to the second fuel gas are more than or equal to 3.
Further, the converter gas is subjected to a cleaning treatment before being subjected to a decarburization treatment.
Further, the coke oven gas is subjected to a purification treatment before being subjected to the hydrogen extraction treatment.
Further, before decarburization treatment, the FINEX gas is subjected to dust removal treatment; preferably, the manner of dust removal treatment of the FINEX gas comprises coarse dust removal and wet dust removal; more preferably, the dust content of the FINEX gas after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the FINEX gas after wet dust removal is less than or equal to 5mg/Nm 3.
Further, the hydrogen-based shaft furnace top gas is subjected to dust removal treatment before being subjected to decarburization and denitrification treatment and before being used as the first fuel gas; preferably, the mode of dust removal treatment of the hydrogen-based shaft furnace top gas comprises coarse dust removal and dry dust removal; more preferably, the dust content of the hydrogen-based shaft furnace top gas after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the hydrogen-based shaft furnace top gas after dry dust removal is less than or equal to 5mg/Nm 3.
Further, the FINEX gas is subjected to pressurization treatment before decarburization treatment; preferably, the pressure of the FINEX gas after pressurization is 0.45-0.55 MPa, and the pressure of the first decarburization gas obtained by decarburization treatment and separation of the FINEX gas under the pressure is 0.4-0.5 MPa.
Further, the converter gas is subjected to pressurization treatment before decarburization treatment; preferably, the pressure of the converter gas after pressurization is 0.45-0.55 MPa, and the pressure of the second decarburization gas obtained by decarburization treatment and separation of the converter gas under the pressure is 0.4-0.5 MPa.
Further, the hydrogen-based shaft furnace top gas is subjected to pressurization treatment before decarburization and denitrification treatment; preferably, the pressure of the pressurized hydrogen-based shaft furnace top gas is 0.45-0.55 MPa, and the pressure of the third decarburization and nitrogen removal gas obtained by decarburization and denitrification treatment separation of the pressurized hydrogen-based shaft furnace top gas is 0.4-0.5 MPa.
Further, the coke oven gas is subjected to pressurization treatment before being subjected to hydrogen extraction treatment; preferably, the pressure of the pressurized coke oven gas is 0.45-0.55 MPa, and the pressure of the hydrogen obtained by hydrogen extraction treatment and separation of the coke oven gas under the pressure is 0.4-0.5 MPa.
Further, the fourth stripping gas is pressurized before being blown into the blast furnace; preferably, the pressure of the fourth desorption gas after pressurization is 0.3-0.4 MPa.
Further, the hydrogen-based shaft furnace top gas is subjected to heat exchange treatment before being subjected to decarburization and denitrification treatment and before being used as the first fuel gas; preferably, the heat exchange treatment mode includes: the temperature of the gas at the top of the hydrogen-based shaft furnace is reduced to below 40 ℃ through heat exchange; more preferably, the heat exchange means includes a multi-stage heat exchange including a primary heat exchange and a secondary heat exchange, the primary heat exchange means including: heat exchanging the hydrogen-based shaft furnace top gas with the third decarbonized and denitrogenated gas, wherein the secondary heat exchanging comprises: heat exchanging is carried out on the hydrogen-based shaft furnace top gas subjected to primary heat exchange and the cooling liquid, so that the temperature of the hydrogen-based shaft furnace top gas is reduced to 40 ℃ or lower; most preferably, after the heat exchange of the hydrogen-based shaft furnace top gas and the third decarburization and dephosphorization, the temperature of the third decarburization and dephosphorization is increased to 323-439 ℃. Wherein, the cooling liquid can adopt cooling water.
Further, after heating the reducing gas, introducing the reducing gas into a hydrogen-based shaft furnace to produce sponge iron; preferably, the reducing gas is introduced into a hydrogen-based shaft furnace to produce sponge iron after being heated to 950-1050 ℃.
Further, the hydrogen content of the reducing gas is 55-95.5%, H 2/CO is more than or equal to 1.4, when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron in year, the amount of the reducing gas introduced is 243550 ～ 317000Nm 3/H, the air pressure is 0.3-0.4 MPa, the temperature is 950-1050 ℃, the metallization rate of the produced sponge iron is 93-95%, and the carbon content is 0.2-3.5%.
Further, when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron annually, the gas quantity of the FINEX gas is 2980-83800 Nm 3/h, and the temperature is 20-50 ℃; at this time, the heat value of the first decarbonized gas obtained by decarbonizing and separating the FINEX gas is 1.45-1.55 times that of the part of the FINEX gas, the gas quantity is 2000-56200 Nm 3/h, the air pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃; further, the heat value of the obtained first desorption gas is 17-18% of that of the FINEX gas, the gas quantity is 985-27680 Nm 3/h, and the temperature is 20-50 ℃.
Further, when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron annually, the gas quantity of the converter gas is 7200-100000 Nm 3/h, and the temperature is 20-50 ℃; at this time, the heat value of the second decarbonizing gas obtained by decarbonizing treatment and separation of the converter gas is 1.05-1.25 times of the heat value of the converter gas, the gas quantity is 5700-79000 Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃; further, the heat value of the obtained second stripping gas is 35-40% of the heat value of the converter gas, the gas quantity is 1500-21200 Nm 3/h, and the temperature is 20-50 ℃.
Further, when the hydrogen-based shaft furnace annual production is 100 ten thousand tons of sponge iron, the hydrogen content of the gas at the top of the hydrogen-based shaft furnace is 38-72%, the CO content is 1-26.5%, the gas quantity is 248000 ～ 319000Nm 3/h, the gas pressure is 0.16-0.26 MPa, and the temperature is 418-534 ℃; at this time, the heat value of the third decarburization and denitrification gas obtained by separating a part of the hydrogen-based shaft furnace top gas through decarburization and denitrification treatment is 1.32-1.40 times that of a part of the hydrogen-based shaft furnace top gas, the gas quantity is 131000 ～ 181000Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃; further, the heating value of the obtained third desorption gas is 32.5-88.3% of the heating value of a part of the top gas of the hydrogen-based shaft furnace, the gas quantity is 6200-60500 Nm 3/h, and the temperature is 20-50 ℃.
Further, when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron in an annual way, the gas quantity of the coke oven gas is 69600-196000 Nm 3/h, the temperature is 20-50 ℃, and the pressure after pressurization is 0.45-0.55 MPa; at this time, the heat value of the hydrogen gas obtained by the separation of the hydrogen extraction treatment of the coke oven gas is 60-70% of the heat value of the coke oven gas, the gas quantity is 33000-93000 Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃; further, the heat value of the obtained fourth desorption gas is 1.15-1.45 times of the heat value of the coke oven gas, the gas quantity is 36600-104000 Nm 3/h, and the temperature is 20-50 ℃; the fourth desorption gas is blown into a blast furnace through a tuyere after being pressurized to carry out low-carbon smelting, oxygen enrichment is carried out while blowing, the oxygen enrichment rate is 14-58%, the coke ratio of the blast furnace is reduced by 25-78 kg/tHM, and the emission of CO 2 is reduced by 6.7-20.8%; preferably, the pressure of the fourth desorption gas after pressurization is 0.3-0.4 MPa.
The gas in the top of the hydrogen-based shaft furnace needs to be noted that the gas quantity of the hour involved in the invention is set for the shaft furnace with 100 ten thousand tons of sponge iron produced annually. When the annual production of sponge iron changes, the gas quantity also needs to be correspondingly adjusted and changed.
The second aspect of the invention provides a steel mill secondary energy recycling and hydrogen metallurgy system, which comprises a third gas treatment unit, a fourth gas treatment unit, a heating device, a hydrogen-based shaft furnace and a blast furnace, wherein the system also comprises a first gas treatment unit and a second gas treatment unit or the system also comprises a first gas treatment unit;
The first gas treatment unit is used for treating FINEX gas and comprises a first decarburization device; the first decarburization device is used for decarburizing the FINEX gas, separating the FINEX gas into first decarburization gas and first desorption gas, and is provided with a first decarburization gas outlet end which is connected with the heating device;
the second gas treatment unit is used for treating converter gas and comprises a first decarburization device; the first decarburization device is used for decarburizing the converter gas, dividing the converter gas into second decarburization gas and second stripping gas, and is provided with a second decarburization gas outlet end which is connected with the heating device;
The third gas treatment unit is used for treating the top gas of the hydrogen-based shaft furnace and comprises a third decarburization and denitrification device; the third decarburization and denitrification device is used for removing CO 2 and N 2 from the top gas of the hydrogen-based shaft furnace, dividing the top gas of the hydrogen-based shaft furnace into third decarburization and denitrification gas and third desorption gas, and is provided with a third decarburization and denitrification gas outlet end, and the third decarburization and denitrification gas outlet end is connected with the heating device;
The fourth gas treatment unit is used for treating coke oven gas and comprises a fourth hydrogen extracting device; the fourth hydrogen extracting device is used for extracting hydrogen from the coke oven gas, dividing the coke oven gas into hydrogen and fourth desorption gas, and is provided with a hydrogen outlet end and a fourth desorption gas outlet end, and the hydrogen outlet end is connected with the heating device;
The heating device is used for heating the first decarburization gas, the second decarburization gas, the third decarburization nitrogen removal gas and the hydrogen; the heating device is provided with a reducing gas outlet end which is connected with the hydrogen-based shaft furnace, and the hydrogen-based shaft furnace adopts the reducing gas to produce sponge iron;
The outlet end of the fourth desorption gas is connected with the blast furnace, and the blast furnace adopts the fourth desorption gas to carry out low-carbon smelting to produce liquid molten iron.
Further, the system also comprises a steelmaking plant, and the first decarburization device is further provided with a first stripping gas outlet which is connected with the steelmaking plant so as to send the first stripping gas into the steelmaking plant for CO 2 steelmaking.
Further, the system further comprises a gas pipe network, the second decarburization device is further provided with a second desorption gas outlet end, and the second desorption gas outlet end is connected with the gas pipe network so as to send the second desorption gas into the gas pipe network.
Further, the third decarburization denitrification device is further provided with a third desorption gas outlet end, the heating device is provided with a second fuel gas inlet end, and the third desorption gas outlet end is connected with the second fuel gas inlet end so as to send the third desorption gas into the heating device to serve as fuel gas for heating.
Further, the outlet end of the third desorption gas is also connected with a gas pipe network so as to send the third desorption gas into the gas pipe network.
Further, the second gas treatment unit further comprises a second purification device, and the second purification device is arranged before the second decarburization device and is used for purifying the converter gas.
Further, the fourth gas treatment unit further comprises a fourth purification device, and the fourth purification device is arranged before the fourth hydrogen extraction device and is used for purifying the coke oven gas.
Further, the first gas treatment unit further comprises a first dust removal device, and the first dust removal device is arranged before the first decarburization device and is used for carrying out dust removal treatment on the FINEX gas.
Further, the third gas treatment unit further comprises a third dust removal device, and the third dust removal device is used for carrying out dust removal treatment on the top gas of the hydrogen-based shaft furnace.
Further, the first gas treatment unit further comprises a first pressurizing machine, and the first pressurizing machine is used for pressurizing the FINEX gas after dust removal; preferably, the first press is disposed between the first dust removing device and the first decarburizing device.
Further, the second gas treatment unit further comprises a second pressurizing machine, and the second pressurizing machine is used for pressurizing the purified converter gas; preferably, the second pressurizing machine is disposed between the second purifying device and the second decarburizing device.
Further, the third gas treatment unit further comprises a third pressurizing machine, and the third pressurizing machine is used for pressurizing the heat-exchanged hydrogen-based shaft furnace top gas; preferably, the third press is disposed between the third dust removing device and the third decarburization and denitrification device.
Further, the fourth gas treatment unit further comprises a fourth pressurizing machine, and the fourth pressurizing machine is used for pressurizing the coke oven gas; preferably, the fourth pressurizing machine is disposed between the fourth purifying device and the fourth hydrogen extracting device.
Further, the fourth gas treatment unit further comprises a fifth pressurizing machine, and the fifth pressurizing machine is arranged between the fourth hydrogen extracting device and the blast furnace and is used for pressurizing the fourth desorption gas.
Further, the third gas treatment unit further comprises a heat exchange device, and the heat exchange device is used for carrying out heat exchange treatment on the hydrogen-based shaft furnace top gas; preferably, the heat exchange device is arranged between the third dust removal device and the third pressurizing machine, the heat exchange device comprises a multi-stage heat exchanger, the multi-stage heat exchanger comprises a primary heat exchanger and a secondary heat exchanger which are sequentially connected, the primary heat exchanger is connected with the third decarburization and nitrogen removal outlet end and is a place for heat exchange between the third decarburization and nitrogen removal device and the hydrogen-based shaft furnace top gas, and the secondary heat exchanger is a place for heat exchange between cooling liquid and the hydrogen-based shaft furnace top gas.
Further, the heating device is also provided with a first fuel gas inlet end, wherein the first fuel gas inlet end is an inlet for feeding the hydrogen-based shaft furnace top gas into the heating device so as to feed the hydrogen-based shaft furnace top gas into the heating device to be used as fuel gas for heating; preferably, the first fuel gas inlet end is connected with the top gas outlet end of the hydrogen-based shaft furnace of the heat exchange device, so that part of the top gas of the hydrogen-based shaft furnace after heat exchange is sent into the heating device to be used as fuel gas for heating.
A third aspect of the invention provides a method according to the first aspect and/or a system according to the second aspect and uses thereof in the field of hydrogen metallurgy.
As described above, the steel mill secondary energy recycling and hydrogen metallurgy method, system and application thereof have the following beneficial effects:
1) The invention extracts and utilizes H 2 in coke oven gas, CO in converter gas and CO in FINEX gas after rich hydrogen and oxygen as reducing gas, thereby fully utilizing the reducing capability of secondary energy of steel mill, replacing reforming reformer with mature and simple gas removal device, and reducing primary energy consumption and equipment investment of hydrogen-based shaft furnace.
2) In the method, the volume fraction of the reducing gas H 2 is 55-96.5%, the temperature is controlled at 950-1050 ℃, and the higher reducing capability is ensured; the CO volume fraction is 1.2-37%, and the carburization amount of 0.2-3.5% of the sponge iron can be effectively realized.
3) According to the invention, methane-rich stripping gas (namely fourth stripping gas) after hydrogen extraction of coke oven gas is blown into the blast furnace, and oxygen-enriched operation is performed at the same time, so that the coke ratio of the blast furnace can be reduced and the CO 2 emission of a combined steel plant can be reduced under the condition that the original blast furnace belly gas amount and theoretical combustion temperature are maintained to be basically unchanged.
In conclusion, the technology provided by the invention provides a new low-carbon and high-efficiency hydrogen metallurgy method for recycling secondary energy sources of steel mills and avoiding high-investment reforming conversion, and has great significance in simplifying the technological process of a hydrogen-based shaft furnace and reducing the carbon emission of the blast furnace.
Drawings
FIG. 1 is a schematic view showing the arrangement of a secondary energy recycling and hydrogen metallurgy system in a steel mill according to an embodiment of the present invention and examples 1 to 8.
FIG. 2 is a schematic view showing the arrangement of a secondary energy recycling and hydrogen metallurgy system in a steel mill according to another embodiment of the present invention and examples 9 to 11.
FIG. 3 is a schematic view showing the arrangement of the secondary energy recycling and hydrogen metallurgy system in the steel mill according to another embodiment of the present invention and example 12.
Reference numerals illustrate:
the first coarse dust collector 11, the first fine dust collector 12, the first pressurizing machine 13, the first decarburization device 14, the second pressurizing machine 21, the second decarburization device 22, the third coarse dust collector 31, the third fine dust collector 32, the heat exchange device 33, the third pressurizing machine 34, the third decarburization denitrification device 35, the fourth pressurizing machine 41, the fourth hydrogen extracting device 42, the fifth pressurizing machine 43, the heating device 50, the hydrogen-based shaft furnace 60, the blast furnace 70, the gas pipe network 80 and the steelmaking workshop 90.
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
The same or similar reference numbers in the drawings of embodiments of the invention correspond to the same or similar components; in the description of the present invention, it should be understood that, if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc., that indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but not for indicating or suggesting that the referred device or element must have a specific azimuth, be constructed and operated in a specific azimuth, so that the terms describing the positional relationship in the drawings are merely for exemplary illustration and should not be construed as limiting the present invention, and that the specific meaning of the above terms may be understood by those of ordinary skill in the art according to the specific circumstances.
The invention provides a secondary energy recycling and hydrogen metallurgy method for a steel mill, which comprises the following steps of:
obtaining byproduct gas of a steel mill, separating out reducing gas, introducing the reducing gas into a hydrogen-based shaft furnace to produce sponge iron, and recycling hydrogen-based shaft furnace top gas discharged from the top of the hydrogen-based shaft furnace;
The byproduct gas of the steel plant comprises FINEX gas, converter gas, hydrogen-based shaft furnace top gas and coke oven gas;
The reducing gas comprises third decarburization nitrogen removal and hydrogen, and further comprises first decarburization gas and/or second decarburization gas;
The first decarburization gas is separated from the FINEX gas through decarburization treatment, the second decarburization gas is separated from the converter gas through decarburization treatment, the third decarburization and nitrogen removal gas is obtained from the hydrogen-based shaft furnace top gas through decarburization and denitrification treatment, and the hydrogen is separated from the coke oven gas through hydrogen extraction treatment;
And the coke oven gas is subjected to hydrogen extraction treatment and separation to obtain the hydrogen and fourth desorption gas, and the fourth desorption gas is blown into a blast furnace for producing liquid molten iron by low-carbon smelting.
The composition of the reducing gas specifically comprises the following three modes:
1. The second decarburization gas, the third decarburization and nitrogen removal gas and the hydrogen are mixed to form a reducing gas;
2. the first decarburization gas, the third decarburization and nitrogen removal gas and the hydrogen are mixed to form a reducing gas;
3. The first decarbonizing gas, the second decarbonizing gas, the third decarbonizing and nitrogen removing gas and hydrogen are mixed to form the reducing gas.
The method of the embodiment extracts and utilizes H 2 in the coke oven gas, CO in the converter gas and CO and H 2 in the FINEX gas as reducing gases, fully utilizes the reduction capability of secondary energy sources of steel mills, replaces a reforming reformer with higher investment by using a mature and simple gas removal device, and reduces the primary energy consumption and equipment investment of the hydrogen-based shaft furnace; the methane-rich stripping gas (namely the fourth stripping gas) after hydrogen extraction of coke oven gas is blown into the blast furnace, and simultaneously the oxygen-rich operation is carried out, so that the coke ratio of the blast furnace can be reduced and the CO 2 emission of the combined steel mill can be reduced under the condition that the original blast furnace belly gas quantity and theoretical combustion temperature are maintained to be basically unchanged.
In another embodiment of the invention, the FINEX gas is decarbonized and separated to obtain the first decarbonized gas and the first desorbed gas, and the first desorbed gas is conveyed to a steelmaking plant for CO 2 steelmaking, so that the full utilization of the FINEX gas is realized.
In another embodiment of the invention, the converter gas is decarbonized and separated to obtain the second decarbonized gas and the second desorbed gas, and the second desorbed gas is conveyed to a steel mill gas pipe network, so that the full utilization of the converter gas can be realized.
In another embodiment of the present invention, the method further comprises: carrying out decarburization denitrification separation on one part of the hydrogen-based shaft furnace top gas to obtain third decarburization denitrification, and taking the other part of the hydrogen-based shaft furnace top gas as a first fuel gas to heat the reducing gas; preferably, the volume fraction of the other part of the hydrogen-based shaft furnace top gas used as the first fuel gas in the hydrogen-based shaft furnace top gas is 3.5-30.5%.
In another embodiment of the invention, a part of the hydrogen-based shaft furnace top gas is subjected to decarburization denitrification separation to obtain the third decarburization denitrification and a third stripping gas, and a part of the third stripping gas is used as a second fuel gas for heating the reducing gas.
In another embodiment of the present invention, the other part of the third stripping gas is delivered to a steel mill gas pipe network. According to the embodiment, the third stripping gas is divided into two parts for use, so that the full utilization of the top gas of the hydrogen-based shaft furnace is realized.
In a specific embodiment, the volume ratio of the first fuel gas to the second fuel gas is greater than or equal to 3, that is, the volume ratio of the other part of the top gas of the hydrogen-based shaft furnace is greater than or equal to 75% (i.e., the usage amount of the first fuel gas) and the volume ratio of the third stripping gas is less than or equal to 25% (i.e., the usage amount of the second fuel gas) in the fuel gas required for heating the reducing gas.
The embodiment uses the third stripping gas and a part of the hydrogen-based shaft furnace top gas as fuel gas to heat the reducing gas, so that external fuel is not needed, and self-sufficiency is realized; it should be noted that the second fuel gas is an alternative fuel gas, or may be considered a supplemental fuel gas, and that when the first fuel gas is deficient, a portion of the third desorption gas may be selected as the supplemental fuel gas for use in heating the reducing gas.
In another embodiment of the present invention, the converter gas is further subjected to a cleaning treatment before being subjected to the decarburization treatment.
In another embodiment of the invention, the coke oven gas is further subjected to a purification treatment prior to the hydrogen stripping treatment.
The purification treatment in the above embodiment means desulfurization purification treatment, namely, removal of organic sulfur and inorganic sulfur from the gas. Preferably, the total sulfur content of the coke oven/converter gas after desulfurization treatment is less than or equal to 10mg/m 3.
In another embodiment of the present invention, the FINEX gas is further subjected to a dust removal treatment before being subjected to a decarburization treatment; preferably, the manner of dust removal treatment of the FINEX gas comprises coarse dust removal and wet dust removal; more preferably, the dust content of the FINEX gas after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the FINEX gas after wet dust removal is less than or equal to 5mg/Nm 3.
In another embodiment of the invention, the hydrogen-based shaft furnace top gas is further dedusted prior to decarbonizing and denitrifying and prior to use as the first fuel gas; preferably, the mode of dust removal treatment of the hydrogen-based shaft furnace top gas comprises coarse dust removal and dry dust removal; more preferably, the dust content of the hydrogen-based shaft furnace top gas after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the hydrogen-based shaft furnace top gas after dry dust removal is less than or equal to 5mg/Nm 3.
In another embodiment of the present invention, the method further comprises: after the FINEX gas is dedusted, the FINEX gas is pressurized before decarburization treatment is performed on the FINEX gas; preferably, the pressure of the FINEX gas after pressurization is 0.45-0.55 MPa, and the pressure of the first decarburization gas obtained after decarburization treatment of the FINEX gas is 0.4-0.5 MPa.
In another embodiment of the present invention, the method further comprises: pressurizing the fourth stripping gas before blowing the fourth stripping gas into a blast furnace for low-carbon smelting; preferably, the pressure of the fourth desorption gas after pressurization is 0.3-0.4 MPa.
In another embodiment of the present invention, the method further comprises: after the converter gas is purified, pressurizing the converter gas before decarburizing the converter gas; preferably, the pressure of the converter gas after pressurization is 0.45-0.55 MPa, and the pressure of the second decarburization gas obtained after decarburization treatment of the converter gas is 0.4-0.5 MPa.
In another embodiment of the present invention, the method further comprises: pressurizing a part of the hydrogen-based shaft furnace top gas before decarburizing and denitrifying the gas; preferably, the pressure of the pressurized hydrogen-based shaft furnace top gas is 0.45-0.55 MPa, and the pressure of the third decarburization and nitrogen removal gas obtained after decarburization and denitrification treatment of a part of the hydrogen-based shaft furnace top gas is 0.4-0.5 MPa.
In another embodiment of the present invention, the method further comprises: after the coke oven gas is purified, the coke oven gas is pressurized before hydrogen extraction treatment is carried out on the coke oven gas; preferably, the pressure of the pressurized coke oven gas is 0.45-0.55 MPa, and the pressure of the hydrogen obtained by hydrogen extraction treatment of the coke oven gas is 0.4-0.5 MPa.
In another embodiment of the present invention, the method further comprises: after dedusting the hydrogen-based shaft furnace top gas, carrying out heat exchange treatment on a part of the hydrogen-based shaft furnace top gas before pressurizing, decarburizing and denitrifying the part of the hydrogen-based shaft furnace top gas and before using the other part of the hydrogen-based shaft furnace top gas as fuel gas for heating the reducing gas; preferably, the heat exchange treatment mode includes: the temperature of the gas at the top of the hydrogen-based shaft furnace is reduced to below 40 ℃ through heat exchange; more preferably, the heat exchange means includes a multi-stage heat exchange including a primary heat exchange and a secondary heat exchange, the primary heat exchange means including: heat exchanging the hydrogen-based shaft furnace top gas with the third decarbonized and denitrogenated gas, wherein the secondary heat exchanging comprises: heat exchanging is carried out on the hydrogen-based shaft furnace top gas subjected to primary heat exchange and the cooling liquid, so that the temperature of the hydrogen-based shaft furnace top gas is reduced to 40 ℃ or lower; most preferably, after the heat exchange of the hydrogen-based shaft furnace top gas and the third decarburization and dephosphorization, the temperature of the third decarburization and dephosphorization is increased to 323-439 ℃. Wherein, the cooling liquid can adopt cooling water.
According to the embodiment, the temperature of the top gas of the hydrogen-based shaft furnace is reduced through heat exchange, so that decarburization and denitrification treatment can be conveniently carried out; the third decarburization and nitrogen removal process is carried out with the gas at the top of the hydrogen-based shaft furnace, so that the waste heat of the gas at the top of the hydrogen-based shaft furnace is fully utilized, the temperature of the third decarburization and nitrogen removal process is increased, and the requirement of a heating link on fuel gas can be reduced; in addition, in order to avoid adverse effect on decarburization and denitrification caused by the too high temperature of the top gas of the hydrogen-based shaft furnace after heat exchange with the third decarburization and denitrification, the cooling liquid can be used for carrying out secondary heat exchange so as to control the temperature of the top gas of the hydrogen-based shaft furnace after heat exchange to be 40 ℃ or below.
In another embodiment of the invention, after heating the reducing gas, introducing the reducing gas into a hydrogen-based shaft furnace to produce sponge iron; preferably, the reducing gas is introduced into a hydrogen-based shaft furnace to produce sponge iron after being heated to 950-1050 ℃.
In another embodiment of the invention, the hydrogen content of the reducing gas is 55-95.5%, H 2/CO is more than or equal to 1.4, when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron in year, the amount of the reducing gas introduced is 243550 ～ 317000Nm 3/H, the air pressure is 0.3-0.4 MPa, the temperature is 950-1050 ℃, the metallization rate of the produced sponge iron is 93-95%, and the carbon content is 0.2-3.5%.
In the embodiment, the volume fraction of the reducing gas H 2 of the hydrogen-based shaft furnace is controlled to be 55-96.5%, and the temperature is controlled to be 950-1050 ℃, so that higher reducing capability is ensured; the volume fraction of CO is controlled to be 1.2-37%, so that the carburization amount of sponge iron of 0.2-3.5% can be effectively realized.
In order to achieve the technical effects, in a specific embodiment, when 100 ten thousand tons of sponge iron are produced in a hydrogen-based shaft furnace in an annual manner, the gas quantity of the FINEX gas is 2980-83800 Nm 3/h, and the temperature is 20-50 ℃; at this time, the heat value of the first decarbonized gas obtained by decarbonizing and separating the FINEX gas is 1.45-1.55 times that of the part of the FINEX gas, the gas quantity is 2000-56200 Nm 3/h, the air pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃; further, the heat value of the obtained first desorption gas is 17-18% of that of the FINEX gas, the gas quantity is 985-27680 Nm 3/h, and the temperature is 20-50 ℃.
In a specific embodiment, when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron in an annual way, the gas quantity of the converter gas is 7200-100000 Nm 3/h, and the temperature is 20-50 ℃; at this time, the heat value of the second decarbonizing gas obtained by decarbonizing treatment and separation of the converter gas is 1.05-1.25 times of the heat value of the converter gas, the gas quantity is 5700-79000 Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃; further, the heat value of the obtained second stripping gas is 35-40% of the heat value of the converter gas, the gas quantity is 1500-21200 Nm 3/h, and the temperature is 20-50 ℃.
In a specific embodiment, when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron in an annual way, the hydrogen content of the top gas of the hydrogen-based shaft furnace is 38-72%, the CO content is 1-26.5%, the gas quantity is 248000 ～ 319000Nm 3/h, the air pressure is 0.16-0.26 MPa, and the temperature is 418-534 ℃; at this time, the heat value of the third decarburization and denitrification gas obtained by separating a part of the hydrogen-based shaft furnace top gas through decarburization and denitrification treatment is 1.32-1.40 times that of a part of the hydrogen-based shaft furnace top gas, the gas quantity is 131000 ～ 181000Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃; further, the heating value of the obtained third desorption gas is 32.5-88.3% of the heating value of a part of the top gas of the hydrogen-based shaft furnace, the gas quantity is 6200-60500 Nm 3/h, and the temperature is 20-50 ℃.
In a specific embodiment, when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron in an annual way, the gas quantity of the coke oven gas is 69600-196000 Nm 3/h, the temperature is 20-50 ℃, and the pressure after pressurization is 0.45-0.55 MPa; at this time, the heat value of the hydrogen gas obtained by the separation of the hydrogen extraction treatment of the coke oven gas is 60-70% of the heat value of the coke oven gas, the gas quantity is 33000-93000 Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃; further, the heat value of the obtained fourth desorption gas is 1.15-1.45 times of the heat value of the coke oven gas, the gas quantity is 36600-104000 Nm 3/h, and the temperature is 20-50 ℃; the fourth desorption gas is blown into a blast furnace through a tuyere after being pressurized to carry out low-carbon smelting, oxygen enrichment is carried out while blowing, the oxygen enrichment rate is 14-58%, the coke ratio of the blast furnace is reduced by 25-78 kg/tHM, and the emission of CO 2 is reduced by 6.7-20.8%; preferably, the pressure of the fourth desorption gas after pressurization is 0.3-0.4 MPa.
In the above embodiment, the method of extracting hydrogen, decarbonizing and denitrifying may be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method. The above methods are all prior art, and the present invention is not described herein in detail.
It should be noted that the amount of hours involved in the above-described embodiments of the invention and in the examples that follow is set for a production of 100 ten thousand tons of sponge iron per year. When the annual production of sponge iron changes, the gas quantity also needs to be correspondingly adjusted and changed. Those skilled in the art can design and adjust the present invention according to the actual situation and needs with reference to the embodiments and examples.
The smelting reduction iron making process is an important process for iron making, is also an important research and development direction of future iron making processes, and besides the FINEX process, the smelting reduction iron making processes put into commercial production currently include COREX and HIsmolt processes. The COREX process has been successfully used in countries such as china, south africa, and india; the domestic introduction time of the HIsmolt process is relatively short, and the HIsmolt process is currently in a digestion and absorption stage, and domestic ironmaking workers are also conducting intensive research on the HIsmolt process. The blast furnace top gas, the COREX gas and the HIsmelt gas contain CO and H 2 like the FINEX gas, and can be used as supplementary gas for hydrogen-based shaft furnace reduction after decarburization. However, it should be noted that the FINEX, COREX and HIsmolt process are different in application scenario, and there is no scenario in one factory at the same time. Therefore, any one of blast furnace top gas, COREX gas and HIsmelt gas may be used instead of or in combination with at least one of FINEX gas and converter gas in the above-described embodiment/example of the present invention, and the same/similar method as in the above-described embodiment/example of the present invention is referred to for decarburization treatment and then reused.
Referring to fig. 1 to 3, an embodiment of the present invention provides a secondary energy recycling and hydrogen metallurgy system for a steel mill, which includes a third gas treatment unit, a fourth gas treatment unit, a heating device 50, a hydrogen-based shaft furnace 60, and a blast furnace 70, and further includes a first gas treatment unit and/or a second gas treatment unit;
the first gas treatment unit is used for treating FINEX gas and comprises a first decarburization device 14; the first decarbonizing device 14 is used for decarbonizing the FINEX gas, separating the FINEX gas into a first decarbonizing gas and a first stripping gas, and is provided with a first decarbonizing gas outlet end which is connected with the heating device 50;
the second gas treatment unit is used for treating converter gas and comprises a first decarburization device 14; the first decarburization device 14 is used for decarburizing the converter gas, dividing the converter gas into a second decarburization gas and a second stripping gas, and is provided with a second decarburization gas outlet which is connected with the heating device 50;
The third gas treatment unit is used for treating the top gas of the hydrogen-based shaft furnace 60 and comprises a third decarburization and denitrification device 35; the third decarbonization and denitrification device 35 is used for removing CO 2 and N 2 from the top gas of the hydrogen-based shaft furnace 60, dividing the top gas of the hydrogen-based shaft furnace 60 into third decarbonization and denitrification gas and third stripping gas, and is provided with a third decarbonization and denitrification outlet end which is connected with the heating device 50;
The fourth gas treatment unit is used for treating coke oven gas and comprises a fourth hydrogen extracting device 42; the fourth hydrogen extracting device 42 is used for extracting hydrogen from the coke oven gas, dividing the coke oven gas into hydrogen and fourth desorption gas, and is provided with a hydrogen outlet end and a fourth desorption gas outlet end, wherein the hydrogen outlet end is connected with the heating device 50;
The heating device 50 is used for heating the first decarburization gas, the second decarburization gas, the third decarburization nitrogen removal gas and the hydrogen; the heating device 50 is provided with a reducing gas outlet end which is connected with a hydrogen-based shaft furnace 60, and the hydrogen-based shaft furnace 60 adopts reducing gas to produce sponge iron;
the outlet end of the fourth desorption gas is connected with a blast furnace 70, and the blast furnace 70 adopts the fourth desorption gas to carry out low-carbon smelting to produce liquid molten iron.
In another embodiment of the present invention, the system further comprises a steelmaking plant 90, and the first decarbonization device 14 is further provided with a first stripping gas outlet connected to the steelmaking plant 90 for feeding the first stripping gas into the steelmaking plant 90 for use in the CO 2 steelmaking.
In another embodiment of the present invention, the system further comprises a gas pipe network 80, and the second decarbonization device 22 is further provided with a second stripping gas outlet connected to the gas pipe network 80 for delivering the second stripping gas into the gas pipe network 80.
In another embodiment of the present invention, the third decarbonizing and denitrifying device 35 is further provided with a third desorption gas outlet, the heating device 50 is provided with a second fuel gas inlet, 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 the fuel gas for heating.
In another embodiment of the present invention, the third stripping gas outlet is also connected to the gas pipe network 80 to send the third stripping gas into the gas pipe network 80.
In another embodiment of the invention, the second gas treatment unit further comprises a second cleaning device (not shown in the figures) arranged before the second decarbonization device 22 for cleaning the converter gas.
In another embodiment of the present invention, the fourth gas treatment unit further includes a fourth purifying device (not shown in the drawing) disposed before the fourth hydrogen extracting device 42 for purifying the coke oven gas.
In another embodiment of the present invention, the first gas treatment unit further comprises a first dust removal device, which is disposed before the first decarbonization device 14, for performing dust removal treatment on the FINEX gas.
In another embodiment of the invention, the third gas treatment unit further comprises a third dust removal device for dust removal of the top gas of the hydrogen-based shaft furnace 60.
In another embodiment of the present invention, the first gas treatment unit further includes a first pressurizing machine 13, and the first pressurizing machine 13 is used for pressurizing the FINEX gas after dust removal; preferably, the first pressurizing machine 13 is arranged between the first dust removing device and the first decarbonizing device 14.
In another embodiment of the invention, the second gas treatment unit further comprises a second pressurizing machine 21, the second pressurizing machine 21 being used for pressurizing the purified converter gas; preferably, the second pressurizing machine 21 is arranged between the second purifying device and the second decarbonizing device 22.
In another embodiment of the invention, the third gas treatment unit further comprises a third pressurizing machine 34, wherein the third pressurizing machine 34 is used for pressurizing the top gas of the hydrogen-based shaft furnace 60 after heat exchange; preferably, the third pressurizing machine 34 is disposed between the third dust removing device and the third decarbonization and denitrification device 35.
In another embodiment of the present invention, the fourth gas treatment unit further comprises a fourth pressurizing machine 41, and the fourth pressurizing machine 41 is used for pressurizing the coke oven gas; preferably, the fourth pressurizing device 41 is disposed between the fourth purifying device and the fourth hydrogen extracting device 42.
In another embodiment of the present invention, the fourth gas treatment unit further comprises a fifth pressure increasing machine 43, the fifth pressure increasing machine 43 being arranged between the fourth hydrogen-extracting device 42 and the blast furnace 70 for pressurizing the fourth stripping gas.
In another embodiment of the invention, the third gas treatment unit further comprises a heat exchange device 33, wherein the heat exchange device 33 is used for carrying out heat exchange treatment on the top gas of the hydrogen-based shaft furnace 60; preferably, the heat exchange device 33 is arranged between the third dust removing device and the third pressurizing machine 34, the heat exchange device 33 comprises a multi-stage heat exchanger, the multi-stage heat exchanger comprises a primary heat exchanger and a secondary heat exchanger which are sequentially connected, the primary heat exchanger is connected with the outlet end of the third decarburization and nitrogen removal device and is a place for heat exchange between the third decarburization and nitrogen removal device and the gas at the top of the hydrogen-based shaft furnace 60, and the secondary heat exchanger is a place for heat exchange between the cooling liquid and the gas at the top of the hydrogen-based shaft furnace 60.
In another embodiment of the present invention, the heating device 50 is further provided with a first fuel gas inlet end, wherein the first fuel gas inlet end is the inlet of the hydrogen-based shaft furnace 60 top gas fed into the heating device 50, so as to feed the hydrogen-based shaft furnace 60 top gas into the heating device 50 as the fuel gas for heating; preferably, the first fuel gas inlet end is connected to the top gas outlet end of the hydrogen-based shaft furnace 60 of the heat exchanging device 33, so that a part of the top gas of the hydrogen-based shaft furnace 60 after heat exchange is fed into the heating device 50 as the fuel gas for heating.
As shown in fig. 1, an embodiment of the present invention provides a secondary energy recycling and hydrogen metallurgy system for a steel mill, which comprises a second gas treatment unit, a third gas treatment unit, a fourth gas treatment unit, a heating device 50, a hydrogen-based shaft furnace 60, a blast furnace 70 and a gas pipe network 80;
Specifically, the second gas treatment unit comprises a second purifying device, a second pressurizing machine 21 and a second decarburization device 22 which are sequentially connected, the converter gas is purified by the second purifying device, the converter gas is pressurized by the second pressurizing machine 21 and then enters the second decarburization device 22 to be decarburized, the converter gas is divided into second decarburization gas and second desorption gas, the second decarburization device 22 is provided with a second decarburization gas outlet end and a second desorption gas outlet end, wherein the second decarburization gas outlet end is connected with the heating device 50, and the second desorption gas outlet end is connected with the gas pipe network 80 so as to send the second desorption gas into the gas pipe network 80;
The third gas treatment unit comprises a third dust collector, a heat exchanger 33, a third pressurizing machine 34 and a third decarburization and denitrification device 35 which are sequentially connected from a gas outlet at the top of the hydrogen shaft furnace, wherein the third dust collector comprises a third coarse dust collector 31 and a third fine dust collector 32, the third fine dust collector 32 is preferably a dry dust collector, and after coarse dust collection and dry dust collection, the top gas of the hydrogen shaft furnace 60 is subjected to primary heat exchange with third decarburization and denitrification in the heat exchanger 33 and then subjected to secondary heat exchange with cooling liquid; then, a part of the top gas of the hydrogen-based shaft furnace 60 enters a third pressurizing machine 34, enters a third decarburization and denitrification device 35 after being pressurized, removes CO 2 and N 2 and is divided into a third decarburization and denitrification gas and a third desorption gas, wherein the third decarburization and denitrification device 35 is provided with a third decarburization and denitrification gas outlet end and a third desorption gas outlet end, the third decarburization and denitrification gas outlet end is connected with the heating device 50, the third desorption gas outlet end is connected with a second fuel gas inlet end so as to send the third desorption gas into the heating device 50 as fuel gas for heating, and the third desorption gas outlet end is also connected with the gas pipe network 80 so as to send the third desorption gas into the gas pipe network 80; the other part of the gas on the top of the hydrogen-based shaft furnace 60 directly enters the heating device 50 to be used as fuel gas after heat exchange;
The fourth gas treatment unit comprises a fourth purifying device, a fourth pressurizing machine 41, a fourth hydrogen extracting device 42 and a fifth pressurizing machine 43 which are sequentially connected, coke oven gas is purified by the fourth purifying device, pressurized by the fourth pressurizing machine 41, enters the fourth hydrogen extracting device 42 to extract hydrogen and is divided into hydrogen and fourth desorption gas, the fourth hydrogen extracting device 42 is provided with a hydrogen outlet end and a fourth desorption gas outlet end, wherein the hydrogen outlet end is connected with the heating device 50, the fourth desorption gas outlet end and the fifth pressurizing machine 43 are sequentially connected with the blast furnace 70, and the fourth desorption gas is blown into the blast furnace 70 through a tuyere to carry out low-carbon smelting after being pressurized by the fifth pressurizing machine 43;
The heating device 50 is used for heating the hydrogen, the second decarburization gas and the third decarburization and dephosphorization gas, and the hydrogen, the second decarburization gas and the third decarburization and dephosphorization 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 with a hydrogen-based shaft furnace 60, and the hydrogen-based shaft furnace 60 adopts reducing gas to produce sponge iron;
The blast furnace 70 performs low-carbon smelting by using the fourth stripping gas to produce liquid molten iron.
As shown in fig. 2, another embodiment of the present invention provides a secondary energy recycling and hydrogen metallurgy system for a steel mill, which comprises a first gas treatment unit, a third gas treatment unit, a fourth gas treatment unit, a heating device 50, a hydrogen-based shaft furnace 60, a blast furnace 70, a gas pipe network 80 and a steel-making shop 90;
Specifically, the first gas treatment unit comprises a first dust removing device, a first pressurizing machine 13 and a first decarburization device 14 which are sequentially connected from a FINEX gas outlet, the first dust removing device comprises a first coarse dust remover 11 and a first fine dust removing device, the first fine dust removing device is preferably a wet dust remover, the FINEX gas enters the first decarburization device 14 for decarburization after coarse dust removal, wet dust removal and pressurization and is divided into first decarburization gas and first desorption gas, the first decarburization device 14 is provided with a first decarburization gas outlet end and a first desorption gas outlet end, wherein the first decarburization gas outlet end is connected with the heating device 50, and the first desorption gas outlet end is connected with the steelmaking workshop 90 so as to send the first desorption gas into the steelmaking workshop 90 for CO 2 steelmaking;
The third gas treatment unit comprises a third dust removing device, a heat exchanging device 33, a third pressurizing machine 34 and a third decarburization and denitrification device 35 which are sequentially connected from a gas outlet at the top of the hydrogen shaft furnace, wherein the third dust removing device comprises a first coarse dust remover 11 and a dry dust remover, and after coarse dust removal and dry dust removal, the gas at the top of the hydrogen shaft furnace 60 is subjected to primary heat exchange with third decarburization and denitrification in the heat exchanging device 33 and then subjected to secondary heat exchange with cooling liquid; then, a part of the top gas of the hydrogen-based shaft furnace 60 enters a third pressurizing machine 34, enters a third decarburization and denitrification device 35 after being pressurized, removes CO 2 and N 2 and is divided into a third decarburization and denitrification gas and a third desorption gas, wherein the third decarburization and denitrification device 35 is provided with a third decarburization and denitrification gas outlet end and a third desorption gas outlet end, the third decarburization and denitrification gas outlet end is connected with the heating device 50, the third desorption gas outlet end is connected with a second fuel gas inlet end so as to send the third desorption gas into the heating device 50 as fuel gas for heating, and the third desorption gas outlet end is also connected with the gas pipe network 80 so as to send the third desorption gas into the gas pipe network 80; the other part of the gas on the top of the hydrogen-based shaft furnace 60 directly enters the heating device 50 to be used as fuel gas after heat exchange;
the fourth gas treatment unit comprises a fourth purifying device, a fourth pressurizing machine 41 and a fourth hydrogen extracting device 42 which are sequentially connected, coke oven gas is purified by the fourth purifying device, the fourth pressurizing machine 41 is pressurized, hydrogen is extracted by the fourth hydrogen extracting device 42 and is divided into hydrogen and fourth desorption gas, the fourth hydrogen extracting device 42 is provided with a hydrogen outlet end and a fourth desorption gas outlet end, wherein the hydrogen outlet end is connected with the heating device 50, and the fourth desorption gas outlet end is connected with the blast furnace 70;
The heating device 50 is used for heating the hydrogen, the second decarburization gas, the third decarburization and dephosphorization gas and the first decarburization gas, and the hydrogen and the third decarburization and dephosphorization 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 with a hydrogen-based shaft furnace 60, and the hydrogen-based shaft furnace 60 adopts reducing gas to produce sponge iron;
The blast furnace 70 performs low-carbon smelting by using the fourth stripping gas to produce liquid molten iron.
As shown in fig. 3, another embodiment of the present invention provides a secondary energy recycling and hydrogen metallurgy system for a steel mill, which comprises 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 shaft furnace 60, a blast furnace 70, a gas pipe network 80 and a steel-making shop 90;
Specifically, the first gas treatment unit comprises a first dust removing device, a first pressurizing machine 13 and a first decarburization device 14 which are sequentially connected from a FINEX gas outlet, wherein the first dust removing device comprises a second coarse dust remover and a second fine dust removing device, the FINEX gas enters the first decarburization device 14 for decarburization after coarse dust removal, wet dust removal and pressurization, and is divided into first decarburization gas and first desorption gas, the first decarburization device 14 is provided with a first decarburization gas outlet end and a first desorption gas outlet end, the first decarburization gas outlet end is connected with the heating device 50, and the first desorption gas outlet end is connected with the steelmaking workshop 90 so as to send fourth desorption gas into the steelmaking workshop 90 for CO 2 steelmaking;
The second gas treatment unit comprises a second purifying device, a second pressurizing machine 21 and a second decarburization device 22 which are sequentially connected, converter gas enters the second decarburization device 22 for decarburization after being purified by the second purifying device and pressurized by the second pressurizing machine 21, and is divided into second decarburization gas and second desorption gas, the second decarburization device 22 is provided with a second decarburization gas outlet end and a second desorption gas outlet end, wherein the second decarburization gas outlet end is connected with the heating device 50, and the second desorption gas outlet end is connected with the gas pipe network 80 so as to send the second desorption gas into the gas pipe network 80;
The third gas treatment unit comprises a third dust removing device, a heat exchanging device 33, a third pressurizing machine 34 and a third decarburization and denitrification device 35 which are sequentially connected from a gas outlet at the top of the hydrogen shaft furnace, wherein the third dust removing device comprises a first coarse dust remover 11 and a dry dust remover, and after coarse dust removal and dry dust removal, the gas at the top of the hydrogen shaft furnace 60 is subjected to primary heat exchange with third decarburization and denitrification in the heat exchanging device 33 and then subjected to secondary heat exchange with cooling liquid; then, a part of the top gas of the hydrogen-based shaft furnace 60 enters a third pressurizing machine 34, enters a third decarburization and denitrification device 35 after being pressurized, removes CO 2 and N 2 and is divided into a third decarburization and denitrification gas and a third desorption gas, wherein the third decarburization and denitrification device 35 is provided with a third decarburization and denitrification gas outlet end and a third desorption gas outlet end, the third decarburization and denitrification gas outlet end is connected with the heating device 50, the third desorption gas outlet end is connected with a second fuel gas inlet end so as to send the third desorption gas into the heating device 50 as fuel gas for heating, and the third desorption gas outlet end is also connected with the gas pipe network 80 so as to send the third desorption gas into the gas pipe network 80; the other part of the gas on the top of the hydrogen-based shaft furnace 60 directly enters the heating device 50 to be used as fuel gas after heat exchange;
the fourth gas treatment unit comprises a fourth purifying device, a fourth pressurizing machine 41 and a fourth hydrogen extracting device 42 which are sequentially connected, coke oven gas is purified by the fourth purifying device, the fourth pressurizing machine 41 is pressurized, hydrogen is extracted by the fourth hydrogen extracting device 42 and is divided into hydrogen and fourth desorption gas, the fourth hydrogen extracting device 42 is provided with a hydrogen outlet end and a fourth desorption gas outlet end, wherein the hydrogen outlet end is connected with the heating device 50, and the fourth desorption gas outlet end is connected with the blast furnace 70;
The heating device 50 is used for heating the hydrogen, the second decarburization gas, the third decarburization and dephosphorization gas and the first decarburization gas, and the hydrogen and the third decarburization and dephosphorization 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 with a hydrogen-based shaft furnace 60, and the hydrogen-based shaft furnace 60 adopts reducing gas to produce sponge iron;
The blast furnace 70 performs low-carbon smelting by using the fourth stripping gas to produce liquid molten iron.
In summary, the technology provided by the embodiment of the invention provides a new low-carbon and high-efficiency hydrogen metallurgy method for avoiding the technical problems of high investment reforming conversion by utilizing secondary energy of a steel mill, and has very important significance for reducing primary energy consumption of a hydrogen-based shaft furnace and reducing carbon emission of the shaft furnace.
The following specific exemplary examples illustrate the invention in detail. It is also to be understood that the following examples are given solely for the purpose of illustration and are not to be construed as limitations upon the scope of the invention, as many insubstantial modifications and variations are within the scope of the invention as would be apparent to those skilled in the art in light of the foregoing disclosure. The specific process parameters and the like described below are also merely examples of suitable ranges, i.e., one skilled in the art can make a suitable selection from the description herein and are not intended to be limited to the specific values described below.
Example 1
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting the system shown in fig. 1, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 1, after pressurizing and extracting hydrogen from the purified coke oven gas, obtaining hydrogen and a fourth desorption gas, heating the hydrogen to be used as a part of reducing gas, and blowing the fourth desorption gas into a blast furnace through a tuyere after pressurizing to perform low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 144647Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 60% of the heat value of the coke oven gas, the gas quantity is 68500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.45 times of that of the coke oven gas, the gas quantity is 76147Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa.
The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 32%. The coke ratio of the blast furnace is reduced by 50kg/tHM, and the emission of CO 2 is reduced by 13.3%.
(3) Converter gas treatment process
And pressurizing and decarbonizing the purified converter gas to obtain second decarbonizing gas and second desorption gas, heating the second decarbonizing gas to serve as a part of reducing gas, and conveying the second desorption gas to a steel mill gas pipe network. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas flow of the converter gas is 93252Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the second decarbonization gas is 1.17 times of that of the converter gas, the gas quantity is 73500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the second desorption gas is 38% of the heat value of the converter gas, the gas quantity is 19752Nm 3/h, the temperature is 40 ℃ and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 38.6%, the CO content is 12.2%, the gas quantity is 299064Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 507 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 15.4% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at the top of the hydrogen-based shaft furnace, and raising the temperature of the third decarbonized and denitrified third decarbonized to 412 ℃.
The heat value of the third decarburization and nitrogen removal is 1.35 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 149835Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The heating value of the third desorption gas is 87.7% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 58113Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the second decarbonization gas and the third decarbonization and denitrification gas become reducing gas of the hydrogen-based shaft furnace after mixed heating, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 55.8%, H 2/CO 3.2, the gas flow 295824Nm 3/H, the gas pressure 0.4MPa, and the temperature 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 2.0 percent.
Example 2
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting the system shown in fig. 1, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 1, after pressurizing and extracting hydrogen from the purified coke oven gas, obtaining hydrogen and a fourth desorption gas, heating the hydrogen to be used as a part of reducing gas, and blowing the fourth desorption gas into a blast furnace through a tuyere after pressurizing to perform low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 161540Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 76500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 85040Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while the blowing, wherein the oxygen enrichment rate is 39%. The coke ratio of the blast furnace is reduced by 60kg/tHM, and the emission of CO 2 is reduced by 16%.
(3) Converter gas treatment process
And pressurizing and decarbonizing the purified converter gas to obtain second decarbonizing gas and second desorption gas, heating the second decarbonizing gas to serve as a part of reducing gas, and conveying the second desorption gas to a steel mill gas pipe network. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas flow of the converter gas is 67243Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the second decarbonization gas is 1.17 times of that of converter gas, the gas quantity is 53000Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the second desorption gas is 38% of the heat value of the converter gas, the gas quantity is 14243Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 47.3 percent, the CO content is 9.2 percent, the gas quantity is 294491Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 484 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 14.5% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at 389 ℃.
The heat value of the third decarburization and nitrogen removal is 1.37 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 157531Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The heating value of the third desorption gas is 82.3% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 44190Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the second decarbonization gas and the third decarbonization and denitrification gas become reducing gas of the hydrogen-based shaft furnace after mixed heating, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 66.5%, H 2/CO was 5.1, the gas flow was 291505Nm 3/H, the gas pressure was 0.4MPa, and the temperature was 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 1.3 percent.
Example 3
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting the system shown in fig. 1, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 1, after pressurizing and extracting hydrogen from the purified coke oven gas, obtaining hydrogen and a fourth desorption gas, heating the hydrogen to be used as a part of reducing gas, and blowing the fourth desorption gas into a blast furnace through a tuyere after pressurizing to perform low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 171043Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 81000Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 90043Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 44%. The coke ratio of the blast furnace is reduced by 68kg/tHM, and the CO 2 emission is reduced by 18.1%.
(3) Converter gas treatment process
And pressurizing and decarbonizing the purified converter gas to obtain second decarbonizing gas and second desorption gas, heating the second decarbonizing gas to serve as a part of reducing gas, and conveying the second desorption gas to a steel mill gas pipe network. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas flow of the converter gas is 51384Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the second decarbonization gas is 1.17 times of that of converter gas, the gas quantity is 40500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the second desorption gas is 38% of the heat value of the converter gas, the gas quantity is 10884Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 52.6%, the CO content is 7.3%, the gas quantity is 289212Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 466 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 14.2% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at 371 deg.c.
The heat value of the third decarburization and nitrogen removal is 1.38 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 160173Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The heating value of the third desorption gas is 79.2% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 35346Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the second decarbonization gas and the third decarbonization and denitrification gas become reducing gas of the hydrogen-based shaft furnace after mixed heating, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 73.2%, H 2/CO was 7.2, the gas flow was 286135Nm 3/H, the gas pressure was 0.4MPa, and the temperature was 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 0.7 percent.
Example 4
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting the system shown in fig. 1, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 1, after pressurizing and extracting hydrogen from the purified coke oven gas, obtaining hydrogen and a fourth desorption gas, heating the hydrogen to be used as a part of reducing gas, and blowing the fourth desorption gas into a blast furnace through a tuyere after pressurizing to perform low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 186880Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 88500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 98380Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 52%. The coke ratio of the blast furnace is reduced by 73kg/tHM, and the CO 2 emission is reduced by 19.5%.
(3) Converter gas treatment process
And pressurizing and decarbonizing the purified converter gas to obtain second decarbonizing gas and second desorption gas, heating the second decarbonizing gas to serve as a part of reducing gas, and conveying the second desorption gas to a steel mill gas pipe network. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas flow of the converter gas is 24740Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the second decarbonization gas is 1.17 times of that of the converter gas, the gas quantity is 19500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the second desorption gas is 38% of the heat value of the converter gas, the gas quantity is 5240Nm 3/h, the temperature is 40 ℃ and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 63.2%, the CO content is 3.7%, the gas quantity is 287905Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 447 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 13.1% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at 352 ℃.
The heat value of the third decarburization and nitrogen removal is 1.37 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 172011Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The heating value of the third desorption gas is 74.3% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 20480Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the second decarbonization gas and the third decarbonization and denitrification gas become reducing gas of the hydrogen-based shaft furnace after mixed heating, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 85.6%, the H 2/CO was 17.3, the gas flow was 284559Nm 3/H, the gas pressure was 0.4MPa, and the temperature was 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 0.3 percent.
Example 5
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting the system shown in fig. 1, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 1, after pressurizing and extracting hydrogen from the purified coke oven gas, obtaining hydrogen and a fourth desorption gas, heating the hydrogen to be used as a part of reducing gas, and blowing the fourth desorption gas into a blast furnace through a tuyere after pressurizing to perform low-carbon and low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 195960Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 92800Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 103160Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 57%. The coke ratio of the blast furnace is reduced by 76kg/tHM, and the CO 2 emission is reduced by 20.3%.
(3) Converter gas treatment process
And pressurizing and decarbonizing the purified converter gas to obtain second decarbonizing gas and second desorption gas, heating the second decarbonizing gas to serve as a part of reducing gas, and conveying the second desorption gas to a steel mill gas pipe network. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas amount of the converter gas is 7232Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the second decarbonization gas is 1.17 times of that of the converter gas, the gas quantity is 5700Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the second desorption gas is 38% of the heat value of the converter gas, the gas quantity is 1532Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 71.8%, the CO content is 1.1%, the gas quantity is 282312Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 426 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 12.3% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at the top of the hydrogen-based shaft furnace, and raising the temperature of the third decarbonized and denitrified third decarbonized to 331 ℃.
The heat value of the third decarburization and nitrogen removal is 1.33 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 181078Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The heating value of the third desorption gas is 70.3% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 10461Nm 3/h, the temperature is 40 ℃ and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the second decarbonization gas and the third decarbonization and denitrification gas become reducing gas of the hydrogen-based shaft furnace after mixed heating, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 95.5%, H 2/CO was 64.3, the gas flow was 279736Nm 3/H, the gas pressure was 0.4MPa, and the temperature was 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 0.2 percent.
Example 6
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting the system shown in fig. 1, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 1, after pressurizing and extracting hydrogen from the purified coke oven gas, obtaining hydrogen and a fourth desorption gas, heating the hydrogen to be used as a part of reducing gas, and blowing the fourth desorption gas into a blast furnace through a tuyere after pressurizing to perform low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 140424Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 66500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 73924Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 31%. The coke ratio of the blast furnace is reduced by 48kg/tHM, and the CO 2 emission is reduced by 12.8%.
(3) Converter gas treatment process
And pressurizing and decarbonizing the purified converter gas to obtain second decarbonizing gas and second desorption gas, heating the second decarbonizing gas to serve as a part of reducing gas, and conveying the second desorption gas to a steel mill gas pipe network. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas flow of the converter gas is 93252Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the second decarbonization gas is 1.17 times of that of the converter gas, the gas quantity is 73500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the second desorption gas is 38% of the heat value of the converter gas, the gas quantity is 19752Nm 3/h, the temperature is 40 ℃ and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 38.3 percent, the CO content is 12.1 percent, the gas quantity is 301836Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 512 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 13.7% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at the top of the hydrogen-based shaft furnace, and raising the temperature of the third decarbonized and denitrified third decarbonized to 417 ℃.
The heat value of the third decarburization and nitrogen removal is 1.35 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 154468Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The heating value of the third desorption gas is 87.6% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 54086Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the second decarbonization gas and the third decarbonization and denitrification gas become reducing gas of the hydrogen-based shaft furnace after mixed heating, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 15%, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 85%.
The hydrogen content of the reducing gas was 55.2%, H 2/CO 3.2, the gas flow 299317Nm 3/H, the gas pressure 0.4MPa, and the temperature 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 1.8 percent.
Example 7
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting the system shown in fig. 1, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 1, after pressurizing and extracting hydrogen from the purified coke oven gas, obtaining hydrogen and a fourth desorption gas, heating the hydrogen to be used as a part of reducing gas, and blowing the fourth desorption gas into a blast furnace through a tuyere after pressurizing to perform low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 137679Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 65200Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 72479Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 30%. The coke ratio of the blast furnace is reduced by 45kg/tHM, and the CO 2 emission is reduced by 12.0%.
(3) Converter gas treatment process
And pressurizing and decarbonizing the purified converter gas to obtain second decarbonizing gas and second desorption gas, heating the second decarbonizing gas to serve as a part of reducing gas, and conveying the second desorption gas to a steel mill gas pipe network. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas flow of the converter gas is 93252Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the second decarbonization gas is 1.25 times of that of the converter gas, the gas quantity is 73500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the second desorption gas is 35% of the heat value of the converter gas, the gas quantity is 19752Nm 3/h, the temperature is 40 ℃ and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 38.2%, the CO content is 12.1%, the gas quantity is 30550Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 514 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 12.4% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at the top of the hydrogen-based shaft furnace, and raising the temperature of the third decarbonized and denitrified third decarbonized to 419 ℃.
The heat value of the third decarburization and nitrogen removal is 1.34 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 158906Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The heating value of the third desorption gas is 87.5% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 51155Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the second decarbonization gas and the third decarbonization and denitrification gas become reducing gas of the hydrogen-based shaft furnace after mixed heating, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 25%, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 75%.
The hydrogen content of the reducing gas was 55.2%, H 2/CO 3.2, the gas flow 301185Nm 3/H, the gas pressure 0.4MPa, and the temperature 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 1.6 percent.
Example 8
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting the system shown in fig. 1, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 1, after pressurizing and extracting hydrogen from the purified coke oven gas, obtaining hydrogen and a fourth desorption gas, heating the hydrogen to be used as a part of reducing gas, and blowing the fourth desorption gas into a blast furnace through a tuyere after pressurizing to perform low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 153094Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.45MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 72500Nm 3/h, the gas pressure is 0.4MPa, and the temperature after heating is 1050 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 80594Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.3MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 30%. The coke ratio of the blast furnace is reduced by 45kg/tHM, and the CO 2 emission is reduced by 12.0%.
(3) Converter gas treatment process
And pressurizing and decarbonizing the purified converter gas to obtain second decarbonizing gas and second desorption gas, heating the second decarbonizing gas to serve as a part of reducing gas, and conveying the second desorption gas to a steel mill gas pipe network. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas flow of the converter gas is 100230Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.45MPa. The heat value of the second decarbonizing gas is 1.05 times of that of the converter gas, the gas quantity is 79000Nm 3/h, the gas pressure is 0.4MPa, and the temperature after heating is 1050 ℃. The heat value of the second desorption gas is 40% of the heat value of the converter gas, the gas quantity is 21230Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 40.1 percent, the CO content is 12.7 percent, the gas quantity is 318767Nm 3/h, the gas pressure is 0.16MPa, and the temperature is 534 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 17.1% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.45MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at 439 deg.C.
The heat value of the third decarburization and nitrogen removal is 1.32 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 159740Nm 3/h, the gas pressure is 0.4MPa, and the furnace is further heated to 1050 ℃. The heating value of the third desorption gas is 88.3% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 60510Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the second decarbonization gas and the third decarbonization and denitrification gas become reducing gas of the hydrogen-based shaft furnace after mixed heating, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 55.8%, H 2/CO 3.2, the gas flow 317686Nm 3/H, the gas pressure 0.3MPa, and the temperature 1050 ℃. The metallization rate of the sponge iron is more than or equal to 95 percent, and the carbon content is 1.9 percent.
Example 9
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting a system shown in fig. 2, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 2, after pressurizing and extracting hydrogen from the purified coke oven gas, hydrogen and a fourth desorption gas are obtained, the hydrogen is heated and used as a part of reducing gas, and the fourth desorption gas is pressurized and then blown into a blast furnace through a tuyere for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 69684Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 33000Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 36684Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while the blowing, wherein the oxygen enrichment rate is 14%. The coke ratio of the blast furnace is reduced by 25kg/tHM, and the CO 2 emission is reduced by 6.7%.
(3) FINEX gas treatment process
And (3) carrying out wet dust removal, pressurization and decarburization on part of the FINEX gas to obtain first decarburization gas and first desorption gas, wherein the first decarburization gas is heated and then used as part of reducing gas, and the first desorption gas is conveyed to a steelmaking workshop CO 2 for steelmaking. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas quantity of the FINEX gas is 83881Nm 3/h, the dust content after coarse dust removal is less than or equal to 6g/Nm 3, the dust content after wet dust removal is less than or equal to 5mg/Nm 3, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the first decarbonizing gas is 1.5 times of that of the FINEX gas, the gas quantity is 56200Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the first desorption gas is 17.9% of that of FINEX gas, the gas quantity is 27681Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 39.7%, the CO content is 26.5%, the gas quantity is 248043Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 485 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 17.9% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at 390 deg.c.
The heat value of the third decarburization and nitrogen removal is 1.40 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 149593Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The heating value of the third desorption gas is 32.5% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 32684Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the third decarbonizing and denitrating gas and the first decarbonizing gas are mixed and heated to become the reducing gas of the hydrogen-based shaft furnace, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 55.1%, H 2/CO was 1.47, the gas flow was 243550Nm 3/H, the gas pressure was 0.4MPa, and the temperature was 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 3.5 percent.
Example 10
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting a system shown in fig. 2, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 2, after pressurizing and extracting hydrogen from the purified coke oven gas, hydrogen and a fourth desorption gas are obtained, the hydrogen is heated and used as a part of reducing gas, and the fourth desorption gas is pressurized and then blown into a blast furnace through a tuyere for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 195115Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 92400Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 102715Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 58%. The coke ratio of the blast furnace is reduced by 78kg/tHM, and the emission of CO 2 is reduced by 20.8%.
(3) FINEX gas treatment process
And (3) carrying out wet dust removal, pressurization and decarburization on part of the FINEX gas to obtain first decarburization gas and first desorption gas, wherein the first decarburization gas is heated and then used as part of reducing gas, and the first desorption gas is conveyed to a steelmaking workshop CO 2 for steelmaking. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas quantity of the FINEX gas is 2985Nm 3/h, the dust content after coarse dust removal is less than or equal to 6g/Nm 3, the dust content after wet dust removal is less than or equal to 5mg/Nm 3, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the first decarbonizing gas is 1.45 times of that of the FINEX gas, the gas quantity is 2000Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the first desorption gas is 18% of that of FINEX gas, the gas quantity is 985Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 70.2%, the CO content is 1.0%, the gas quantity is 276415Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 418 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 3.5% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at the top of the hydrogen-based shaft furnace, and raising the temperature of the third decarbonized and denitrified third decarbonized to 323 ℃.
The heat value of the third decarburization and nitrogen removal is 1.36 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 173971Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The third desorption gas heat value is 71.9% of the heat value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 6249Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the third decarbonizing and denitrating gas and the first decarbonizing gas are mixed and heated to become the reducing gas of the hydrogen-based shaft furnace, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 94.6%, H 2/CO was 75, the gas flow was 273320Nm 3/H, the gas pressure was 0.4MPa, and the temperature was 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 0.2 percent.
Example 11
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting a system shown in fig. 2, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 2, after pressurizing and extracting hydrogen from the purified coke oven gas, hydrogen and a fourth desorption gas are obtained, the hydrogen is heated and used as a part of reducing gas, and the fourth desorption gas is pressurized and then blown into a blast furnace through a tuyere for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 84466Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 70% of the heat value of the coke oven gas, the gas quantity is 40000Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 1050 ℃.
(2) Blast furnace low-carbon smelting process
The heating value of the fourth desorption gas delivered to the blast furnace is 1.15 times of that of the coke oven gas, the gas quantity is 44466Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 30%. The coke ratio of the blast furnace is reduced by 30kg/tHM, and the CO 2 emission is reduced by 8%.
(3) FINEX gas treatment process
And (3) carrying out wet dust removal, pressurization and decarburization on part of the FINEX gas to obtain first decarburization gas and first desorption gas, wherein the first decarburization gas is heated and then used as part of reducing gas, and the first desorption gas is conveyed to a steelmaking workshop CO 2 for steelmaking. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas quantity of the FINEX gas is 81940Nm 3/h, the dust content after coarse dust removal is less than or equal to 6g/Nm 3, the dust content after wet dust removal is less than or equal to 5mg/Nm 3, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the first decarbonizing gas is 1.55 times of that of the FINEX gas, the gas quantity is 54900Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 1050 ℃. The heat value of the first desorption gas is 17% of that of FINEX gas, the gas quantity is 27040Nm 3/h, the temperature is 40 ℃, and the air pressure is 0.02MPa.
(4) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 43.6%, the CO content is 25.1%, the gas quantity is 268191Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 504 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 15.9% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at 411 ℃.
The heat value of the third decarburization and nitrogen removal is 1.36 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 163771Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 1050 ℃. The heating value of the third desorption gas is 34.7% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 30950Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(5) Hydrogen-based shaft furnace smelting process
The hydrogen, the third decarbonizing and denitrating gas and the first decarbonizing gas are mixed and heated to become the reducing gas of the hydrogen-based shaft furnace, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 58.8%, H 2/CO 1.7, the gas flow 264147Nm 3/H, the gas pressure 0.4MPa, and the temperature 1050 ℃. The metallization rate of the sponge iron is more than or equal to 95 percent, and the carbon content is 0.2 percent.
Example 12
The secondary energy recycling and hydrogen metallurgy method of the steel mill is carried out by adopting a system shown in fig. 3, and comprises the following specific steps:
(1) Coke oven gas treatment process
As shown in fig. 3, after pressurizing and extracting hydrogen from the purified coke oven gas, hydrogen and a fourth desorption gas are obtained, the hydrogen is heated and used as a part of reducing gas, and the fourth desorption gas is pressurized and then blown into a blast furnace through a tuyere for low-carbon smelting. The hydrogen extraction method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The gas amount of the coke oven gas is 117196Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the hydrogen is 65% of the heat value of the coke oven gas, the gas quantity is 55500Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃.
(2) Blast furnace low-carbon smelting process
The heat value of the fourth desorption gas delivered to the blast furnace is 1.3 times of that of the coke oven gas, the gas quantity is 61696Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.4MPa. The pressurized fourth desorption gas is blown into a blast furnace through a tuyere to carry out low-carbon smelting, and oxygen enrichment is carried out while blowing, wherein the oxygen enrichment rate is 25%. The coke ratio of the blast furnace is reduced by 45kg/tHM, and the CO 2 emission is reduced by 12.0%.
(3) Converter gas treatment process
And pressurizing and decarbonizing the purified converter gas to obtain second decarbonizing gas and second desorption gas, heating the second decarbonizing gas to serve as a part of reducing gas, and conveying the second desorption gas to a steel mill gas pipe network. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas flow of the converter gas is 65974Nm 3/h, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the second decarbonization gas is 1.17 times of that of the converter gas, the gas flow is 52000Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the second desorption gas is 38% of the heat value of the converter gas, the gas quantity is 13974Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(4) FINEX gas treatment process
And (3) carrying out wet dust removal, pressurization and decarburization on part of the FINEX gas to obtain first decarburization gas and first desorption gas, wherein the first decarburization gas is heated and then used as part of reducing gas, and the first desorption gas is conveyed to a steelmaking workshop CO 2 for steelmaking. The decarburization method may be any one or more of physical absorption method, chemical absorption method, and physical-chemical absorption method.
The gas quantity of the FINEX gas is 39104Nm 3/h, the dust content after coarse dust removal is less than or equal to 6g/Nm 3, the dust content after wet dust removal is less than or equal to 5mg/Nm 3, the temperature is 40 ℃, and the pressure after pressurization is 0.55MPa. The heat value of the first decarbonizing gas is 1.5 times of that of the FINEX gas, the gas quantity is 26200Nm 3/h, the gas pressure is 0.5MPa, and the temperature after heating is 950 ℃. The heat value of the first desorption gas is 17.9% of that of FINEX gas, the gas quantity is 12904Nm 3/h, the temperature is 40 ℃, and the air pressure is 0.02MPa.
(5) Hydrogen-base shaft furnace top gas circulation process
And (3) carrying out dust removal, heat exchange, pressurization, decarburization and denitrification on the top gas of the hydrogen-based shaft furnace to obtain third decarburization and denitrification gas and third desorption gas, wherein the third decarburization and denitrification gas is heated and then used as part of reducing gas, one part of the third desorption gas is used for heating fuel gas by the reducing gas, and the other part of the third desorption gas is conveyed to a steel mill gas pipe network. The decarbonization and denitrification method can be any one or more of physical absorption method, chemical absorption method and physical-chemical absorption method.
The hydrogen content of the top gas of the hydrogen-based shaft furnace is 38.5%, the CO content is 14.8%, the gas quantity is 273076Nm 3/h, the gas pressure is 0.26MPa, and the temperature is 487 ℃; the dust content of the top gas of the hydrogen-based shaft furnace after coarse dust removal is less than or equal to 6g/Nm 3, and the dust content of the top gas of the hydrogen-based shaft furnace after dry dust removal is less than or equal to 5mg/Nm 3; the temperature of the top gas of the hydrogen-based shaft furnace is reduced to be less than or equal to 40 ℃ after two-stage heat exchange with third decarburization and nitrogen removal and cooling water; 30.5% of the top gas of the hydrogen-based shaft furnace after heat exchange is used as fuel gas for heating the reducing gas; pressurizing the rest part of the top gas of the hydrogen-based shaft furnace after heat exchange, and raising the pressure to 0.55MPa; and performing primary heat exchange between the decarbonized and denitrified third decarbonized and denitrified gas at the top of the hydrogen-based shaft furnace, and raising the temperature of the third decarbonized and denitrified third decarbonized to 392 ℃.
The heat value of the third decarburization and nitrogen removal is 1.35 times of that of the top gas of the hydrogen-based shaft furnace, the gas quantity is 131908Nm 3/h, the gas pressure is 0.5MPa, and the furnace is further heated to 950 ℃. The heating value of the third desorption gas is 77.3% of the heating value of the top gas of the hydrogen-based shaft furnace, the gas quantity is 58065Nm 3/h, the temperature is 40 ℃, and the gas pressure is 0.02MPa.
(6) Hydrogen-based shaft furnace smelting process
The hydrogen, the second decarbonizing gas, the third decarbonizing and the first decarbonizing gas are mixed and heated to become the reducing gas of the hydrogen-based shaft furnace, and qualified sponge iron is produced. The fuel gas heated by the reducing gas is hydrogen-based shaft furnace top gas subjected to third desorption gas and heat exchange, the volume fraction of the third desorption gas is 0, and the volume fraction of the hydrogen-based shaft furnace top gas subjected to heat exchange is 100%.
The hydrogen content of the reducing gas was 55.7%, H 2/CO was 2.6, the gas flow was 271761Nm 3/H, the gas pressure was 0.4MPa, and the temperature was 950 ℃. The metallization rate of the sponge iron is more than or equal to 93 percent, and the carbon content is 3.1 percent.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (15)
1. A steel mill secondary energy recycling and hydrogen metallurgy method is characterized by comprising the following steps:
obtaining byproduct gas of a steel mill, separating out reducing gas, introducing the reducing gas into a hydrogen-based shaft furnace to produce sponge iron, and recycling hydrogen-based shaft furnace top gas discharged from the top of the hydrogen-based shaft furnace;
The byproduct gas of the steel plant comprises FINEX gas, converter gas, hydrogen-based shaft furnace top gas and coke oven gas;
the reducing gas comprises a first decarburization gas, a second decarburization gas, a third decarburization and dephosphorization gas and hydrogen, or the reducing gas comprises a first decarburization gas, a third decarburization and dephosphorization gas and hydrogen;
The first decarburization gas is separated from the FINEX gas through decarburization treatment, the second decarburization gas is separated from the converter gas through decarburization treatment, the third decarburization and nitrogen removal gas is obtained from the hydrogen-based shaft furnace top gas through decarburization and denitrification treatment, and the hydrogen is separated from the coke oven gas through hydrogen extraction treatment;
And the coke oven gas is subjected to hydrogen extraction treatment and separation to obtain the hydrogen and fourth desorption gas, and the fourth desorption gas is blown into a blast furnace for producing liquid molten iron by low-carbon smelting.
2. The method of claim 1, further comprising at least one of the following operations ① to ④:
① The FINEX gas is subjected to decarburization and separation to obtain the first decarburization gas and a first desorption gas, and the first desorption gas is conveyed to a steelmaking workshop for CO 2 steelmaking;
② The converter gas is subjected to decarburization and separation to obtain second decarburization gas and second desorption gas, and the second desorption gas is conveyed to a steel mill gas pipe network;
③ Carrying out decarburization denitrification separation on one part of the hydrogen-based shaft furnace top gas to obtain third decarburization denitrification, and taking the other part of the hydrogen-based shaft furnace top gas as a first fuel gas to heat the reducing gas; ;
④ And a part of the hydrogen-based shaft furnace top gas is subjected to decarburization denitrification separation to obtain the third decarburization and denitrification gas and a third stripping gas, and a part of the third stripping gas is used as a second fuel gas for heating the reducing gas.
3. The method of claim 2, wherein the operation ③ further comprises: the volume fraction of the other part of the hydrogen-based shaft furnace top gas used as the first fuel gas in the hydrogen-based shaft furnace top gas is 3.5-30.5%;
And/or, the operations ④ further include: the other part of the third desorption gas is conveyed to a steel mill gas pipe network;
And/or, when the method further comprises operations ③ and ④, the volumetric usage ratio of the first fuel gas and the second fuel gas is greater than or equal to 3.
4. The method of claim 1 or 2, further comprising a pretreatment comprising at least one of a purification, dust removal, pressurization, heat exchange treatment;
The purification treatment is selected from at least one of the following operations ⑤ to ⑥:
⑤ The converter gas is further purified before decarburization treatment;
⑥ The coke oven gas is also subjected to purification treatment before hydrogen extraction treatment;
the dust removal treatment is selected from at least one of the following operations ⑦ to ⑧:
⑦ The FINEX gas is also subjected to dust removal treatment before decarburization treatment
⑧ The hydrogen-based shaft furnace top gas is subjected to dust removal treatment before being subjected to decarburization and denitrification treatment and before being used as first fuel gas;
the pressurizing treatment is selected from the following operations ⑨ to ⑨ At least one of:
⑨ Before decarburization treatment, the FINEX gas is subjected to pressurization treatment;
⑩ The converter gas is subjected to pressurization treatment before decarburization treatment;
The hydrogen-based shaft furnace top gas is subjected to pressurization treatment before decarburization and denitrification treatment;
The coke oven gas is subjected to pressurization treatment before hydrogen extraction treatment;
before the fourth desorption gas is sprayed into the blast furnace, pressurizing treatment is further carried out;
The heat exchange treatment mode comprises the following steps: the hydrogen-based shaft furnace top gas is subjected to heat exchange treatment before being subjected to decarburization and denitrification treatment and before being used as a first fuel gas.
5. The method according to claim 4, wherein: the heat exchange treatment mode comprises the following steps: the temperature of the hydrogen-based shaft furnace top gas is reduced to 40 ℃ or below by heat exchange.
6. The method according to claim 4, wherein: the heat exchange treatment mode is heat exchange, the heat exchange mode comprises multi-stage heat exchange, the multi-stage heat exchange comprises primary heat exchange and secondary heat exchange, and the primary heat exchange mode comprises the following steps: heat exchanging the hydrogen-based shaft furnace top gas with the third decarbonized and denitrogenated gas, wherein the secondary heat exchanging comprises: and carrying out heat exchange on the hydrogen-based shaft furnace top gas subjected to primary heat exchange and the cooling liquid.
7. The method according to claim 1, characterized in that: and after heating the reducing gas, introducing the reducing gas into a hydrogen-based shaft furnace to produce sponge iron.
8. The method according to claim 1, characterized in that: the hydrogen content of the reducing gas is 55-95.5%, H 2/CO is more than or equal to 1.4, when the annual production of 100 ten thousand tons of sponge iron by the hydrogen-based shaft furnace is realized, the gas quantity of the introduced reducing gas is 243550 ～ 317000Nm 3/H, the gas pressure is 0.3-0.4 MPa, the temperature is 950-1050 ℃, the metallization rate of the produced sponge iron is 93-95%, and the carbon content is 0.2-3.5%.
9. The method according to claim 8, wherein: when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron in an annual way, the gas quantity of the FINEX gas is 2980-83800 Nm 3/h, and the temperature is 20-50 ℃; at this time, the heat value of the first decarbonizing gas obtained by decarbonizing and separating the FINEX gas is 1.45-1.55 times of the heat value of the FINEX gas, the gas quantity is 2000-56200 Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃;
When the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron annually, the gas quantity of the converter gas is 7200-100000 Nm 3/h, and the temperature is 20-50 ℃; at this time, the heat value of the second decarbonizing gas obtained by decarbonizing treatment and separation of the converter gas is 1.05-1.25 times of the heat value of the converter gas, the gas quantity is 5700-79000 Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃;
When the hydrogen-based shaft furnace annual production is 100 ten thousand tons of sponge iron, the hydrogen content of the gas at the top of the hydrogen-based shaft furnace is 38-72%, the CO content is 1-26.5%, the gas quantity is 248000 ～ 319000Nm 3/h, the gas pressure is 0.16-0.26 MPa, and the temperature is 418-534 ℃; at this time, the heat value of the third decarburization and denitrification gas obtained by separating a part of the hydrogen-based shaft furnace top gas through decarburization and denitrification treatment is 1.32-1.40 times that of a part of the hydrogen-based shaft furnace top gas, the gas quantity is 131000 ～ 181000Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃;
When the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron in an annual way, the gas quantity of the coke oven gas is 69600-196000 Nm 3/h, the temperature is 20-50 ℃, and the pressure after pressurization is 0.45-0.55 MPa; at this time, the heat value of the hydrogen gas obtained by the separation of the hydrogen extraction treatment of the coke oven gas is 60-70% of the heat value of the coke oven gas, the gas quantity is 33000-93000 Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃.
10. The method according to claim 9, wherein: when the hydrogen-based shaft furnace produces 100 ten thousand tons of sponge iron in an annual way, the gas quantity of the coke oven gas is 69600-196000 Nm 3/h, the temperature is 20-50 ℃, and the pressure after pressurization is 0.45-0.55 MPa; at this time, the heat value of the hydrogen gas obtained by the separation of the hydrogen extraction treatment of the coke oven gas is 60-70% of the heat value of the coke oven gas, the gas quantity is 33000-93000 Nm 3/h, the gas pressure is 0.4-0.5 MPa, and the temperature after heating is 950-1050 ℃; the calorific value of the obtained fourth desorption gas is 1.15-1.45 times of the calorific value of the coke oven gas, the gas quantity is 36600-104000 Nm 3/h, and the temperature is 20-50 ℃; and the fourth desorption gas is blown into a blast furnace through a tuyere after being pressurized to carry out low-carbon smelting, oxygen enrichment is carried out while blowing, the oxygen enrichment rate is 14-58%, the coke ratio of the blast furnace is reduced by 25-78 kg/tHM, and the emission of CO 2 is reduced by 6.7-20.8%.
11. A steel mill secondary energy recycling and hydrogen metallurgy system is characterized in that: the system comprises a third gas treatment unit, a fourth gas treatment unit, a heating device, a hydrogen-based shaft furnace and a blast furnace, and further comprises a first gas treatment unit and a second gas treatment unit or further comprises a first gas treatment unit;
The first gas treatment unit is used for treating FINEX gas and comprises a first decarburization device; the first decarburization device is used for decarburizing the FINEX gas, separating the FINEX gas into first decarburization gas and first desorption gas, and is provided with a first decarburization gas outlet end which is connected with the heating device;
the second gas treatment unit is used for treating converter gas and comprises a first decarburization device; the first decarburization device is used for decarburizing the converter gas, dividing the converter gas into second decarburization gas and second stripping gas, and is provided with a second decarburization gas outlet end which is connected with the heating device;
The third gas treatment unit is used for treating the top gas of the hydrogen-based shaft furnace and comprises a third decarburization and denitrification device; the third decarburization and denitrification device is used for removing CO 2 and N 2 from the top gas of the hydrogen-based shaft furnace, dividing the top gas of the hydrogen-based shaft furnace into third decarburization and denitrification gas and third desorption gas, and is provided with a third decarburization and denitrification gas outlet end, and the third decarburization and denitrification gas outlet end is connected with the heating device;
The fourth gas treatment unit is used for treating coke oven gas and comprises a fourth hydrogen extracting device; the fourth hydrogen extracting device is used for extracting hydrogen from the coke oven gas, dividing the coke oven gas into hydrogen and fourth desorption gas, and is provided with a hydrogen outlet end and a fourth desorption gas outlet end, and the hydrogen outlet end is connected with the heating device;
The heating device is used for heating the first decarburization gas, the second decarburization gas, the third decarburization nitrogen removal gas and the hydrogen; the heating device is provided with a reducing gas outlet end which is connected with the hydrogen-based shaft furnace, and the hydrogen-based shaft furnace adopts the reducing gas to produce sponge iron;
The outlet end of the fourth desorption gas is connected with the blast furnace, and the blast furnace adopts the fourth desorption gas to carry out low-carbon smelting to produce liquid molten iron.
12. The system of claim 11, further comprising at least one of the following devices: the system comprises a gas pipe network, a steelmaking workshop, a second purifying device, a fourth purifying device, a first dust removing device, a third dust removing device, a first pressurizing machine, a second pressurizing machine, a third pressurizing machine, a fourth pressurizing machine, a fifth pressurizing machine and a heat exchanging device;
the first decarburization device is further provided with a first desorption gas outlet end which is connected with a steelmaking workshop so as 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 with a gas pipe network so as to send the second desorption gas into the gas pipe network;
The third decarburization denitrification device is also provided with a third desorption gas outlet end, the heating device is provided with a second fuel gas inlet end, and the third desorption gas outlet end is connected with the second fuel gas inlet end so as to send the third desorption gas into the heating device to be used as fuel gas for heating;
the third desorption gas outlet end is also connected with a gas pipe network so as to send the third desorption gas into the gas pipe network;
The second gas treatment unit further comprises a second purification device, wherein the second purification device is arranged before the second decarburization device and is used for purifying the converter gas;
the fourth gas treatment unit further comprises a fourth purification device, wherein the fourth purification device is arranged before the fourth hydrogen extracting device and is used for purifying the coke oven gas;
The first gas treatment unit further comprises a first dust removal device, wherein the first dust removal device is arranged in front of the first decarburization device and is used for carrying out dust removal treatment on the FINEX gas;
The third gas treatment unit further comprises a third dust removal device, wherein the third dust removal device is used for carrying out dust removal treatment on the top gas of the hydrogen-based shaft furnace;
The first gas treatment unit further comprises a first pressurizing machine, and the first pressurizing machine is used for pressurizing the FINEX gas after dust removal;
the second gas treatment unit further comprises a second pressurizing machine, and the second pressurizing machine is used for pressurizing the purified converter gas;
the third gas treatment unit further comprises a third pressurizing machine, and the third pressurizing machine is used for pressurizing the heat-exchanged hydrogen-based shaft furnace top gas;
the fourth gas treatment unit further comprises a fourth pressurizing machine, and the fourth pressurizing machine is used for pressurizing the coke oven gas;
The fourth gas treatment unit further comprises a fifth pressurizing machine, and the fifth pressurizing machine is arranged between the fourth hydrogen extracting device and the blast furnace and is used for pressurizing the fourth desorption gas.
The heat exchange device is used for carrying out heat exchange treatment on the gas at the top of the hydrogen-based shaft furnace.
13. The system according to claim 12, wherein: the heat exchange device comprises a multi-stage heat exchanger, the multi-stage heat exchanger comprises a primary heat exchanger and a secondary heat exchanger which are sequentially connected, the primary heat exchanger is connected with the outlet end of the third decarburization and nitrogen removal gas and is used for heat exchange between the third decarburization and nitrogen removal gas and the top gas of the hydrogen-based shaft furnace, and the secondary heat exchanger is used for heat exchange between cooling liquid and the top gas of the hydrogen-based shaft furnace.
14. The system according to claim 11, wherein: the heating device is also provided with a first fuel gas inlet end, and the first fuel gas inlet end is an inlet for feeding the hydrogen-based shaft furnace top gas into the heating device so as to feed the hydrogen-based shaft furnace top gas into the heating device to be used as fuel gas for heating.
15. Use of the method according to any one of claims 1 to 10 and/or the system according to any one of claims 11 to 14 in the field of hydrogen metallurgy.
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