CN107299175A - A kind of system and method for fluid bed gas, gas-based reduction and electric furnace steel making coupling - Google Patents
A kind of system and method for fluid bed gas, gas-based reduction and electric furnace steel making coupling Download PDFInfo
- Publication number
- CN107299175A CN107299175A CN201710606854.8A CN201710606854A CN107299175A CN 107299175 A CN107299175 A CN 107299175A CN 201710606854 A CN201710606854 A CN 201710606854A CN 107299175 A CN107299175 A CN 107299175A
- Authority
- CN
- China
- Prior art keywords
- gas
- furnace
- fluidized bed
- inlet
- coal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- 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
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/46—Gasification of granular or pulverulent flues in suspension
- C10J3/54—Gasification of granular or pulverulent fuels by the Winkler technique, i.e. by fluidisation
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Combustion & Propulsion (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The present invention relates to the system and method that a kind of fluid bed gas, gas-based reduction, electric furnace steel making are coupled, the system includes fluid bed, gas-based reduction device and electric furnace；Fluid bed includes air distribution plate, Gas injection mouth, fluid bed feed bin and gas exit；Gas-based reduction device includes the shaft furnace and iron charge tank being connected with each other；Shaft furnace includes gas entry and oxidation agglomerate feed bin, and gas entry is connected with gas exit, and iron charge tank is exported including reduced iron；Electric furnace includes reduced iron entrance, electric furnace feed bin and tapping hole, and electric furnace reduction iron entrance is connected with the outlet of iron charge tank reduced iron.The present invention is coupled by the technique of fluid bed gas gas base directly reducing electric furnace steel making, eliminate fluid bed cooling, washing, the dedusting of coal gas is made and heat up again the process of heating, reduce system investments and make full use of gas heat, reduce the energy resource consumption of shaft furnace heated by gas, and filtered out preferably parameter, whole process optimised process is found out, the Best Coupling of equipment room manufacturing parameter is realized.
Description
Technical Field
The invention relates to the technical field of chemical metallurgy, in particular to a system and a method for fluidized bed gas making, gas-based direct reduction and electric furnace steelmaking.
Background
Compared with the traditional blast furnace process, the gas-based shaft furnace direct reduction-electric furnace process has the advantages of relatively short process, no coking coal, high yield of single set of equipment, energy conservation, emission reduction of CO2Has obvious effect and other technical advantages, can help the iron and steel industry to get rid of the trip of coking coal resources, and realize energy consumption reduction and CO2Emission reduction is the mainstream technology of the coke-free iron making technology at present. The gas-based direct reduction method can improve the structure of steel products and becomes a low-carbon green advanced iron-making technology for improving the quality of the steel products, so that the gas-based direct reduction method gradually replaces the traditional blast furnace iron-making process and is widely applied in the world. The prior direct reduction process mainly uses natural gas as a reducing agent, and a reducing agent cracking heating furnace (a petrochemical furnace) is a petrochemical furnace which is difficult to exceed 900 ℃. However, petroleum and natural gas resources in China are relatively deficient, and the primary energy structure mainly based on coal in China cannot be changed for a long time in the future.
The pyrolysis is a basic process of coal thermal processing, the characteristics of the pyrolysis have great influence on the further conversion of the coal, and the reduced coal gas for reducing iron ore can be obtained from the coal and the high-quality reducing agent semi-coke can be provided for electric furnace steelmaking through the pyrolysis. The fluidized bed gasification furnace takes coal powder as a raw material, and gasifying agents (such as steam/air or oxygen) enter the gasification furnace from the bottom of the gasification furnace at a certain speed to enable the coal powder in a bed layer to be fluidized by boiling, and combustion and gasification reactions occur in the process, so that the temperature of the whole bed layer is uniformly distributed, a local overheating phenomenon cannot occur, but the gas outlet temperature is very high, the heat loss is large, a waste heat recovery system with a large scale is generally required to be arranged, and the large-area large-equipment investment is caused.
The prior art discloses a method and a system for gasifying pulverized coal and directly reducing metallurgy in a gas-based shaft furnace, wherein the pulverized coal is reacted with gasifying agent oxygen and water vapor after entering a gasification furnace to generate high-temperature gas, the high-temperature gas is quenched to 600-2The raw synthesis gas is subjected to water vapor shift and purification and then is used as a reducing agent to be conveyed to a heater to be heated to 820-960 ℃ for reaction. However, the method has long gas treatment process and large equipment investment, and the reduction gas enters the temperature reduction and temperature rise process to cause energy waste.
The prior art also discloses a combined process flow for producing direct reduced iron by using 180-kiloton/alpha scale Shell coal gasification and HYL/Energironon shaft furnace, wherein high-temperature coal gas is converted into clean coal gas through heat exchange and wet washing dust removal of a waste heat boiler, the clean coal gas enters a sulfur-tolerant shift unit after the temperature is reduced to 170 ℃, CO and H in the coal gas2O is converted into H2And CO2. Will transform netThe temperature of the coal gas is raised to 340 ℃, the coal gas is cooled by a heat exchanger and then enters a desulfurization and decarburization process, wherein the desulfurization and decarburization adopt an MDEA process, and the reduced coal gas is heated to 930 ℃ and then enters a shaft furnace to directly reduce iron ore pellets. Therefore, the process flow of the high-temperature coal gas cooling and heating, the desulfurization and decarburization transformation and the pressurization turbine decompression process is long, the equipment investment is large, the energy consumption is large, and the energy waste is also caused.
Disclosure of Invention
In view of the above technical problems, the present invention is directed to a system for coupling fluidized bed coal gas production, shaft furnace direct reduction and electric furnace steelmaking, which organically combines coal chemical industry with steel production and reduces production equipment, thereby omitting the processes of high temperature gas desulfurization and decarburization, cooling, heating and gas compression, achieving the purposes of effectively utilizing sensible heat of high temperature gas, avoiding high temperature corrosion of carbon dioxide or water vapor in the gas to the pipeline of the traditional heating furnace, reducing process equipment and reducing energy consumption.
In order to achieve the aim, the invention provides a system for coupling fluidized bed gas making, gas-based reduction and electric furnace steelmaking, which is characterized by comprising a fluidized bed, a gas-based shaft furnace and an electric furnace; wherein,
the fluidized bed comprises an air distribution plate, a gas inlet, a first material inlet and a coal gas outlet, wherein the gas inlet is arranged at the bottom of a bed layer of the fluidized bed, the air distribution plate is arranged above the gas inlet, the coal gas outlet is arranged at the top of the fluidized bed, and the first material inlet is arranged above the air distribution plate;
the gas-based shaft furnace comprises a gas inlet, a second material inlet and a reduced iron outlet, wherein the gas inlet is arranged at the bottom of the reduction section of the gas-based shaft furnace and is connected with the gas outlet, and the second material inlet is arranged at the top of the gas-based shaft furnace;
the electric furnace comprises a reduced iron inlet and a steel tapping hole, and the reduced iron inlet is connected with the reduced iron outlet through a high-temperature conveying belt.
Furthermore, the system also comprises an oxidation briquette preparation unit, wherein the oxidation briquette preparation unit is sequentially connected with a mixer, a forming unit, a screening machine, a drying kiln, a preheating furnace, a roasting furnace, a cooling unit and a screening device, the screening device comprises an oxidation briquette outlet, and the oxidation briquette outlet is connected with the oxidation briquette storage bin. Preferably, the forming unit is a briquetting machine or a pelletizer. Preferably, the cooling unit is a circular cooler.
Preferably, the system further comprises a heating furnace arranged between the fluidized bed and the gas-based shaft furnace, and the heating furnace is respectively connected with a gas outlet of the fluidized bed and a gas inlet of the gas-based shaft furnace through gas pipelines.
Further, the system also comprises a coal drying furnace, wherein the coal drying furnace is provided with a first material outlet and a high-temperature gas inlet, and the first material outlet is connected with a first material inlet of the fluidized bed.
Preferably, the shaft furnace further comprises a flue gas outlet arranged at the top of the shaft furnace, and the flue gas outlet is connected with a high-temperature gas inlet of the coal drying furnace.
The invention also provides a method for coupling fluidized bed gas making, gas-based reduction and electric furnace steelmaking by using the system, which comprises the following steps:
a, fluidized bed gas making: : adding a carbonaceous raw material and a desulfurizing agent into a fluidized bed from a first material inlet of the fluidized bed, introducing oxidizing gas from a gas inlet of the fluidized bed, and carrying out gasification reaction on the first material and the oxidizing gas to obtain coal gas; wherein the bed pressure of the fluidized bed is 0.25MPa-0.8MPa, and the bed temperature is 750-;
b, gas-based reduction: conveying the coal gas obtained in the step A to a gas-based shaft furnace through a coal gas inlet, putting an iron mineral material into the gas-based shaft furnace through a second material inlet, and performing reduction reaction and heat exchange on the coal gas and the iron mineral material to generate direct reduced iron;
c, steel making: conveying the direct reduced iron obtained in the step B by using a high-temperature conveying belt, adding the direct reduced iron into an electric furnace through a reduced iron inlet of the electric furnace, and carrying out reduction smelting to obtain finished steel and furnace slag; wherein, a reducing agent and a slagging and dephosphorizing agent are added in the smelting process.
In a preferred step C, the reducing agent is selected from coke, semi coke or anthracite, etc. for reducing the iron oxide in the direct reduced iron to metallic iron; the slagging agent is selected from dolomite, limestone or lime and the like and is used for slagging and dephosphorization.
Preferably, in step a, the carbonaceous raw material can be coal or semi-coke, and the addition mode is preferably that a spiral feeder is used for adding; the oxidizing gas may be steam, pure oxygen, or a mixture of steam and pure oxygen. Preferably, the molar ratio of carbon in the carbonaceous feedstock to the oxidizing gas is in the range of from 1.1 to 1.25: 1.
Further, the coal gas generated by the fluidized bed can be directly sent to the gas-based shaft furnace in a hot mode, or heated by a heating furnace and then sent to the gas-based shaft furnace; the furnace is preferably a radiant tube furnace.
Preferably, the fluidized bed gas making process further comprises the step of drying the carbonaceous feedstock and the desulfurizing agent before adding into the fluidized bed. The heat source for drying is preferably flue gas from the top of the shaft furnace; the temperature of the flue gas is 300-550 ℃, preferably 350-450 ℃. Further, when the carbonaceous feedstock is selected from semi-coke, then no drying process is required.
Specifically, the particle size of the carbonaceous feedstock is controlled to be 2-8 mm. The mass ratio of the carbonaceous raw material to the desulfurizing agent is controlled to be 100: 1-4.
Furthermore, the sum of the volume contents of carbon dioxide and water vapor in the coal gas obtained after the fluidized bed reaction is 7-13%; preferably 10.12 to 11.91%.
Preferably, the method further comprises the step of preparing the iron ore into oxidized lumps before the gas-based reduction; wherein, this step includes:
mixing the iron ore material with a binder and water in a mixer; conveying the obtained mixture to a forming unit and forming; conveying the obtained pellets or briquettes (hereinafter referred to as briquettes) into a sieving machine to sieve the pellets or briquettes to obtain briquettes with certain granularity; drying the block mass with certain granularity by using a drying kiln; sending the dried briquette to a preheating furnace for preheating to obtain a preheated briquette; the preheated briquette is sent to a roasting furnace for oxidizing roasting; and cooling the pellets obtained after roasting by a cooling unit, screening by a screening device to obtain the oxidized pellets with a certain granularity, and conveying the oxidized pellets to the gas-based shaft furnace for reaction.
Specifically, the mass ratio of the iron ore material, the binder and the water is 100:0.8-2.0: 5-10. The iron mineral material is selected from iron concentrate powder.
Preferably, the particle size of the iron material is controlled to be less than 200 meshes and accounts for 60-80% by mass.
Further, controlling the granularity of the lumps after being screened by the screening machine to be 9-20 mm; and returning the lumps smaller than the granularity and the lumps larger than the granularity to the forming unit for forming again.
Preferably, the drying temperature in the drying kiln is 120-250 ℃. Preferably, the drying time is 3min to 10 min.
Furthermore, in the double-section preheating furnace, the preheating temperature of the 1 st-section preheating furnace is 450-600 ℃, and the preheating time is 4-10 min. The preheating temperature of the preheating furnace in the 2 nd section is 600-.
Further, the roasting temperature in the roasting furnace is 1100-1300 ℃. The roasting time is 10-30 min.
Preferably, the particle size of the oxidized agglomerates after being sieved by the sieving device is controlled to be 8-20 mm.
Further, the temperature of the gas at the inlet of the shaft furnace is controlled at 750-. The pressure in the furnace is controlled to be 0.2MPa to 0.75MPa, preferably 0.2MPa to 0.6 MPa. The residence time of the oxidation mass in the reduction section of the shaft furnace is controlled to be 3.5-9 h.
Further, the pressure in the fluidized bed is greater than the pressure in the shaft furnace of the shaft furnace, and the pressure difference between the fluidized bed and the shaft furnace is 0.05-0.15 MPa. Thus, the gas generated by the fluidized bed can be directly put into the shaft furnace for use without turbine pressure reduction.
Specifically, in the step B, the reducing agent is added in an amount so that the content of ferrous oxide in the slag obtained in the step C is controlled to be 12-20%.
Specifically, in the step C, the slagging agent and the dephosphorizing agent are added in an amount so that the alkalinity of the slag is controlled to be 1.5-2.8.
The technical scheme adopted by the invention has the following advantages:
(1) the invention provides a coupling process of fluidized bed gas making-gas base direct reduction-electric furnace steelmaking, which takes fluidized bed coal gas as a reducing agent, and the fluidized bed coal gas can be directly used in a shaft furnace without cooling, washing, dust removal and heating processes, because the coal gas made by the fluidized bed has better matching degree with the shaft furnace compared with the coal gas made by other gas making process coupling shaft furnace direct reduction, the gas making pressure is within 0.8MPa, and the direct reduction pressure of the shaft furnace is also within 0.8MPa, the coal gas generated by the fluidized bed does not need turbine depressurization, the system investment is reduced, the energy consumption of the heating of the shaft furnace coal gas is reduced by fully utilizing the sensible heat of the coal gas, and the high-temperature corrosion of carbon dioxide or vapor in the coal gas to the pipeline of the traditional heating furnace is avoided.
(2) The reduced iron is continuously and thermally conveyed to the electric furnace through the high-temperature conveyer belt, so that the power consumption is reduced, the energy consumption of the whole process is reduced by 21%, the production rate is improved by more than 16%, and the production cost is greatly reduced.
(3) Screening out better parameters, and searching out the optimal process of the whole flow, wherein the optimal coupling of production parameters among equipment is realized if the difference between the pressure of fluidized bed gas production and the pressure of the shaft furnace is 0.05-0.15 MPa.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a schematic view of a system for fluidized bed gas production-gas based direct reduction-electric furnace steelmaking according to the present invention;
1-fluidized bed, 2-gas-based shaft furnace, 3-electric furnace, 4-heating furnace and 5-gas pipeline;
11-air distribution plate, 12-gas inlet, 13-first material inlet, 14-coal gas outlet;
21-furnace body, 22-iron material tank, 23-coal gas inlet, 24-second material inlet, 25-reduced iron outlet and 26-flue gas outlet;
31-reduced iron inlet, 32-electric furnace bin and 33-steel outlet.
Detailed Description
The following detailed description of the present invention, taken in conjunction with the accompanying drawings and examples, is provided to enable the invention and its various aspects and advantages to be better understood. However, the specific embodiments and examples described below are for illustrative purposes only and are not limiting of the invention.
In the present invention, the terms "reduced iron" and "direct reduced iron" are the same as each other and may be replaced with each other.
The invention aims to provide a system for coupling fluidized bed coal gas production, shaft furnace direct reduction and electric furnace steelmaking so as to effectively utilize sensible heat of high-temperature coal gas, avoid high-temperature corrosion of carbon dioxide or water vapor in the coal gas to a traditional heating furnace pipeline, reduce flow equipment and reduce energy consumption.
In order to achieve the above purpose, the present invention provides a coupling system of fluidized bed gas making, gas-based reduction and electric furnace steel making, as shown in fig. 1, the system comprises a fluidized bed 1, a gas-based shaft furnace 2 and an electric furnace 3; wherein,
the fluidized bed 1 comprises an air distribution plate 11, a gas inlet 12, a first material inlet 13 and a coal gas outlet 14, wherein the gas inlet 12 is arranged at the bottom of a bed layer of the fluidized bed 1, the air distribution plate 11 is arranged above the gas inlet 12, the coal gas outlet 14 is arranged at the top of the fluidized bed 1, and the first material inlet 13 is arranged above the air distribution plate 11;
the gas-based shaft furnace 2 comprises a furnace body 21 and an iron material tank 22 which are connected with each other; the furnace body 21 comprises a coal gas inlet 23 and a second material inlet 24, the coal gas inlet 23 is arranged in the middle of the furnace body 21 (namely the bottom of the reduction section) and is connected with the coal gas outlet 14, and the second material inlet 24 is arranged at the top of the furnace body 21; the iron bucket 22 comprises a reduced iron outlet 25;
the electric furnace includes a reduced iron inlet 31, an electric furnace bin 32 and a tap hole 33, and the reduced iron inlet 31 and the reduced iron outlet 25 are connected through a high temperature conveyor belt.
Further, the system further comprises an oxidation briquette preparation unit (not shown), wherein the oxidation briquette preparation unit is sequentially connected by a mixer, a forming unit, a screening machine, a drying kiln, a preheating furnace, a roasting furnace, a cooling unit and a screening device, the screening device comprises an oxidation briquette outlet, and the oxidation briquette outlet is connected with the oxidation briquette bin. Preferably, the forming unit is a briquetting machine or a pelletizer. Preferably, the cooling unit is a circular cooler.
Preferably, the system further comprises a heating furnace 4 arranged between the fluidized bed and the gas-based shaft furnace, wherein the heating furnace 4 is respectively connected with a gas outlet 14 of the fluidized bed 1 and a gas inlet of the gas-based shaft furnace through gas pipelines 5.
Further, the system further comprises a coal drying oven (not shown) having a first material outlet connected to the first material inlet 13 of the fluidized bed 1 and a high temperature gas inlet.
Preferably, the gas-based shaft furnace further comprises a flue gas outlet 26 arranged at the top of the furnace, and the flue gas outlet is connected with a high-temperature gas inlet of the coal drying furnace.
The invention also provides a method for coupling fluidized bed gas making, gas-based reduction and electric furnace steelmaking by using the system, which comprises the following steps:
A. fluidized bed gas making: adding a carbonaceous raw material and a desulfurizing agent into a fluidized bed from a first material inlet of the fluidized bed, introducing oxidizing gas from a gas inlet of the fluidized bed, and carrying out gasification reaction on the first material and the oxidizing gas to obtain coal gas; wherein the bed pressure of the fluidized bed is 0.25MPa-0.8MPa, and the bed temperature is 750-;
the obtained coal gas mainly contains CO and H2、CH4And a small amount of CO2、H2O(g)、H2S, the content of carbon dioxide and water vapor in the coal gas at the outlet of the fluidized bed is about 10 percent; the main principle of fluidized bed coal gasification is as follows:
C+H2O＝CO+H2C+O2＝CO2C+CO2methane and CnHm gas obtained by decomposing 2CO and volatile components;
B. gas-based reduction: the coal gas is introduced from a coal gas inlet at the bottom of the reduction section of the shaft furnace, and is reduced and subjected to heat exchange with iron ore added from the top of the shaft furnace from top to bottom, and the generated reduced iron is stored in an iron charge tank; wherein, the reduction principle is as follows:
2Fe2O3+CO(H2)＝Fe3O4+CO2(H2O) (1)
Fe3O4+CO(H2)＝3FeO+CO2(H2O) (2)
FeO+CO(H2)＝Fe+CO2(H2O) (3)
because the coal gas is not reformed by methane, the coal gas contains methane, water vapor and carbon dioxide, the following reactions also occur in the shaft furnace:
CH4+CO2＝CO+H2CH4+H2O＝CO+H2
C. steel making: the method comprises the steps of melting, reducing and refining the reduced iron after the reduced iron enters an electric furnace, adding a carbon-containing raw material as a reducing agent to reduce iron oxide in the reduced iron into metallic iron after a smelting process, then carrying out slagging and dephosphorization on an obtained reduction product, carrying out slagging-off after the dephosphorization is finished for preventing rephosphorization, and carrying out molten steel alloying treatment to remove impurity components such as oxygen, sulfur and the like in steel so as to ensure that the content of all elements in the finally obtained finished steel meets standard requirements. Wherein the carbonaceous raw material is selected from coke, semi coke or anthracite, etc.; the agent for slagging and dephosphorizing is selected from dolomite, limestone or lime, etc. In an electric furnace, the principle of reducing the content of ferrous oxide in direct reduced iron and slagging is as follows:
(FeO)+[C]＝[Fe]+CO，(P2O5)+3(FeO)＝3(FeO.P2O5)，P2O5+4(CaO)＝(4CaO.P2O5)
preferably, in step a, the carbonaceous raw material can be coal or semi-coke, and the addition mode is preferably that a spiral feeder is used for adding; the oxidizing gas may be steam, pure oxygen, or a mixture of steam and pure oxygen.
Furthermore, the coal gas generated by the fluidized bed can be directly sent to the shaft furnace in a hot mode or sent to the shaft furnace after being heated by a heating furnace without decarburization and desulfurization, cooling and dehydration and pressurization depressurization treatment; the furnace is preferably a radiant tube furnace.
Preferably, the fluidized bed gas making process further comprises the step of drying the carbonaceous raw material and the desulfurizing agent before adding into the fluidized bed; the heat source for drying is preferably flue gas from the top of the shaft furnace, thereby reducing the energy consumption of the system; the temperature of the flue gas is 300-550 ℃, preferably 350-450 ℃. Further, when the carbonaceous feedstock is selected from semi-coke, then no drying process is required.
Specifically, the particle size of the carbonaceous raw material is controlled to be 2-8mm, the particle size is too coarse, the heat transfer is slow, the carbon gasification rate is low, the carbon content remained in ash slag is increased, the energy waste is caused, the particle size is too fine, the dust amount carried out by water gas is increased, equipment pipelines and valves are blocked, and the energy waste is caused. The mass ratio of the carbonaceous raw material to the desulfurizer is controlled to be 100:1-4, the desulfurizer has low proportion and low desulfurization rate, sulfur enters coal gas in the form of hydrogen sulfide and finally enters the shaft furnace to directly reduce iron, and the quality of the directly reduced iron is reduced; the desulfurizing agent has too high proportion, occupies the material bed space of the fluidized bed, reduces the coal gas productivity, and the desulfurizing agent needs to absorb heat from cold to hot, thus leading to the increase of gasification energy consumption.
Furthermore, for better coupling with the shaft furnace direct reduction process, the molar ratio of carbon to steam, pure oxygen or the mixture of steam and pure oxygen in the carbonaceous raw material is controlled to be 1.1-1.25:1, and the ratio can reduce the content of carbon dioxide and steam in coal gas and does not cause waste of excessive carbon.
Specifically, the pressure in the fluidized bed is controlled to be 0.25MPa-0.8 MPa. The bed temperature is 750 ℃ and 900 ℃. The pressure in the bed is too low, the amount of the coarse coal powder brought out by the coarse coal gas is large, the coal gasification speed is low, coal resource waste is caused, the productivity is reduced, the pressure is too high, fluidized bed equipment and valve materials are easy to damage, and the maintenance cost of equipment production is increased. The temperature is too low, the coal gasification speed is low, and the productivity is reduced; the temperature is too high, and fluidized bed equipment and valve material are easily damaged, lead to the maintenance cost increase of equipment production.
Furthermore, the volume content of carbon dioxide and water vapor in the coal gas obtained after the fluidized bed reaction is 7-13%.
Preferably, the method further comprises the step of preparing the iron ore into oxidized lumps before the gas-based reduction; wherein, this step includes:
mixing the iron ore with a binder and water in a mixer; conveying the obtained mixture to a briquetting machine or a pelletizer and then pelletizing or briquetting; conveying the obtained pellets or briquettes (hereinafter referred to as briquettes) into a sieving machine to sieve the pellets or briquettes to obtain briquettes with certain granularity; drying the block mass with certain granularity by using a drying kiln; conveying the dried briquette to a double-section preheating furnace for preheating to obtain a preheated briquette; the preheated briquette is sent to a roasting furnace for oxidizing roasting; and cooling the pellets obtained after roasting by using an annular cooler, screening the oxidized pellets with a certain granularity by using a screening device, conveying the oxidized pellets to a shaft furnace workshop, hanging the oxidized pellets into a bin at the top of the shaft furnace, and conveying the oxidized pellets to the shaft furnace for reaction.
Specifically, the mass ratio (mass ratio) of the iron ore, the binder and the water is 100:0.8-2.0:5-10, and too high or too low of moisture and binder is not favorable for balling or briquetting. The iron ore is selected from iron concentrate powder.
Preferably, the particle size of the iron ore is controlled to be-200 mesh (the particle size is less than 200 mesh) accounting for 60-80%.
Further, controlling the granularity of the lumps after being screened by the screening machine to be 9-20 mm; wherein, the lumps with the granularity smaller than the granularity and the lumps with the granularity larger than the granularity are returned to be re-pelletized or briquetted after being re-finely ground.
Preferably, the drying temperature in the drying kiln is 120-250 ℃. The drying time is 3-10 min.
Furthermore, in the double-section preheating furnace, the preheating temperature of the 1 st-section preheating furnace is 450-600 ℃, and the preheating time is 4-10 min. The preheating temperature of the preheating furnace in the 2 nd section is 600-.
Further, the roasting temperature in the roasting furnace is 1100-1300 ℃. The roasting time is 10-30 min.
Preferably, the particle size of the oxidized agglomerates after being sieved by the sieving device is controlled to be 8-20 mm.
Further, the temperature of the gas at the inlet of the shaft furnace is controlled at 750-. The pressure in the furnace is controlled to be 0.2MPa to 0.75MPa, preferably 0.2MPa to 0.6 MPa. The residence time of the oxidation mass in the reduction zone of the shaft furnace is controlled within 3.5-9h, preferably 6-7 h.
Preferably, the tapping temperature of the reduced iron is controlled at 800 ℃ and is directly added into the electric furnace through a high-temperature conveyer belt in a continuous mode without being cooled by a cooling section.
Further, the method further comprises: in order to prevent the reoxidation of the reduced iron discharged from the furnace, before the reduced iron generated by the shaft furnace is stored in the iron charging bucket, inert gas is introduced into the iron charging bucket or a layer of coal powder or semi-coke is sprayed on the iron charging bucket.
Specifically, in order to facilitate dephosphorization, in the step C, the reducing agent is added in an amount to control the content of ferrous oxide in the slag to be 12-20%; the iron content is too high, the iron recovery rate is reduced, iron resource waste is caused, the iron content is too low, the slag oxidation degree is too low, the dephosphorization effect is poor, and the quality of steel grades is influenced.
Further, the basicity of the slag obtained after the electric furnace is reduced is controlled to be 1.5-2.8 by utilizing a slagging and dephosphorizing agent. If the proportion of the added slagging agent and the dephosphorizing agent is too small, the alkalinity is low, the dephosphorization is not facilitated, the melting temperature of the slag is reduced, and the quality in the steel is poor and the energy consumption is high. The proportion of the added slagging agent and the dephosphorizing agent is too large, the cold lime material is heated to the temperature of slag tapping and the tapping temperature to absorb heat, and the energy consumption is increased.
The fluidized bed coal gas-shaft furnace direct reduction-electric furnace steelmaking process of the present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited thereto, and reference may be made to conventional techniques for process parameters not particularly noted.
Example 1
Drying the crushed and sieved coal with the granularity of 2-8mm and lime in a drying furnace, wherein the heat source of the dried coal is gas-based direct reduction shaft furnace top gas flue gas, the temperature of the shaft furnace top gas is 450 ℃, conveying the dried and dehydrated coal powder to a fluidized bed bin for later use, and adding the coal through a spiral feeder.
Firstly, raw material coal and a desulfurizer are fed into a feeder from a bin and are added into a fluidized bed, and the mass ratio of the coal to the desulfurizer is 100: 1.5. And (3) introducing steam from the bottom of the bed layer, wherein the molar ratio of carbon to steam in the coal powder in the production process is 1.15:1 for better coupling with the shaft furnace direct reduction process. The pressure in the bed is controlled at 0.25MPa, and the temperature in the bed is 850 ℃. The contents of carbon dioxide and water vapor in the coal gas at the outlet of the fluidized bed are respectively 6.52 percent and 5.39 percent. The main principle of fluidized bed coal gasification is as follows:
C+H2O＝CO+H2，C+O2＝CO2，C+CO22CO, and methane and CnHm gas obtained by decomposition of volatile components, the main components and contents of the gas are shown in table 1.
Table 1 main components and contents of gas%
| Composition (I) | CO | H2 | CO2 | H2O | CH4 | CnHm |
| Content (wt.) | 35.16 | 45.27 | 6.52 | 5.39 | 6.35 | 0.96 |
The generated coal gas is directly conveyed to the shaft furnace to directly reduce the iron ore oxidized pellets without decarbonization, desulfurization, temperature reduction, dehydration and pressurization depressurization treatment. The main components and contents of the iron ore and the oxidized pellets are shown in tables 2 and 3.
TABLE 2 iron ore main components and contents%
| TFe | Fe2O3 | FeO | CaO | MgO | SiO2 | Al2O3 | S | P |
| 68.55 | 69.11 | 26.00 | 0.22 | 0.35 | 2.76 | 1.49 | 0.04 | 0.07 |
TABLE 3 main component content of oxidized pellets%
| TFe | Fe2O3 | FeO | CaO | MgO | SiO2 | Al2O3 | S | P |
| 66.13 | 94.00 | 0.50 | 0.22 | 0.36 | 3.25 | 1.28 | 0.01 | 0.01 |
Preparing shaft furnace oxidized pellets: uniformly mixing iron ore concentrate powder crushed and ground to 200 meshes and accounting for 60-80% of the iron ore concentrate powder, a binder and water according to the mass ratio of 100:1.0:6.5 by a mixer, and briquetting the mixture by a briquetting machine, wherein the briquetting machine is used for briquetting the mixture with too high or too low moisture and binder. Sieving the produced briquette by a sieving machine, conveying the sieved briquette 9-20mm into a drying kiln for drying at 120 ℃ for 10min, returning the briquette larger than or smaller than the granularity to grinding and briquetting, conveying the dried briquette into a 2-section preheating furnace for preheating, preheating at 600 ℃ for 5min in a 1-section preheating furnace and at 900 ℃ for 10min in a 2-section preheating furnace, conveying the briquette in the 2-section preheating furnace into a roasting furnace for roasting, and roasting at 1150 ℃ for 15 min. And (3) cooling the roasted blocks by a circular cooler, discharging the blocks out of the furnace, screening the blocks to obtain 8-20mm blocks, conveying the 8-20mm blocks to a workshop of the shaft furnace, and hoisting the blocks into a bin at the top of the shaft furnace. The briquettes are continuously added from the top of the shaft furnace, coal gas is introduced from the bottom of a reduction section of the shaft furnace, the temperature of the coal gas at an inlet of the shaft furnace is 810 ℃, the pressure in the furnace is controlled to be 0.2MPa, the iron ore briquettes stay in the reduction section for 5 hours, and the high-temperature coal gas and the briquettes from top to bottom are reduced and subjected to heat exchange, wherein the reduction principle is as follows:
2Fe2O3+CO(H2)＝Fe3O4+CO2(H2O) (1)
Fe3O4+CO(H2)＝3FeO+CO2(H2O) (2)
FeO+CO(H2)＝Fe+CO2(H2O) (3)
the solid direct reduced iron reduced by the shaft furnace is directly and continuously discharged without being cooled by a cooling section, and the main components and the content of the reduced iron are shown in table 4.
TABLE 4 reduced iron main components and contents%
| TFe | MFe | FeO | S | P | CaO | MgO | SiO2 | Al2O3 |
| 89.86 | 82.67 | 9.25 | 0.01 | 0.014 | 0.30 | 0.49 | 4.41 | 2.15 |
The reduced iron is continuously added into an electric arc furnace for steelmaking through a high-temperature conveyer belt, the tapping temperature is 800 ℃, the reduced iron is melted, reduced and refined after entering the electric furnace, and coke (the mass ratio of the reduced iron to the coke is 100:3) is added as a reducing agent after the smelting process, so that iron oxide in the reduced iron is reduced into metallic iron. In order to facilitate dephosphorization, the reducing agent is added in an amount to control the content of ferrous oxide in the slag to be 12-20%. In order to control the alkalinity of the slag to be 1.5-2.8, the adding amount ratio of the lime as a slagging and dephosphorizing agent to the direct reduced iron is 13: 100. According to the reduction and slagging principle of the ferrous oxide content in the electric furnace direct reduced iron: (FeO) + [ C]＝[Fe]+CO，(P2O5)+3(FeO)＝3(FeO.P2O5)，P2O5+4(CaO)＝(4CaO.P2O5) (ii) a In order to prevent rephosphorization, after dephosphorization is finished, slagging-off (CaO + SiO) is required2＝CaSiO3) After slagging off, molten steel alloying operation is carried out for removing oxygen, sulfur and other impurity components in the steel, and the content of all elements in the finished steel is ensured to meet the standard requirement.
Example 2
Conveying the semicoke and the calcium carbonate with the granularity of 2-8mm after crushing and screening to a fluidized bed bin for later use, and adding the coal through a spiral feeder.
Firstly, raw material coal and a desulfurizer are fed into a feeder from a bin and are added into a fluidized bed, and the mass ratio of the coal to the desulfurizer is 100:1. Pure oxygen is introduced from the bottom of the bed layer, and the molar ratio of carbon to the pure oxygen in the coal powder in the production process is 1.1:1 for better coupling with the direct reduction process of the shaft furnace. The pressure in the bed was controlled at 0.4MPa and the bed temperature was 750 ℃. The contents of carbon dioxide and water vapor in the coal gas at the outlet of the fluidized bed are respectively 6.01 percent and 5.33 percent. The main principle of fluidized bed coal gasification is as follows:
C+H2O＝CO+H2，C+O2＝CO2，C+CO22CO, and methane and CnHm gas obtained by decomposition of volatile components, the main components and contents of the gas are shown in table 1.
TABLE 5 main components and contents of gas%
| Composition (I) | CO | H2 | CO2 | H2O | CH4 | CnHm |
| Content (wt.) | 39.18 | 42.01 | 6.01 | 5.33 | 6.59 | 0.88 |
The generated coal gas is directly conveyed to the shaft furnace to directly reduce the iron ore oxidized pellets without decarbonization, desulfurization, temperature reduction, dehydration and pressurization depressurization treatment. The main components and contents of iron ore and oxidized pellets are shown in tables 6 and 7.
TABLE 6 iron ore main components and contents%
| TFe | Fe2O3 | FeO | CaO | MgO | SiO2 | Al2O3 | S | P |
| 68.55 | 69.11 | 26.00 | 0.22 | 0.35 | 2.76 | 1.49 | 0.04 | 0.07 |
TABLE 7 main component content of oxidized pellets%
| TFe | Fe2O3 | FeO | CaO | MgO | SiO2 | Al2O3 | S | P |
| 66.13 | 94.00 | 0.50 | 0.22 | 0.36 | 3.25 | 1.28 | 0.01 | 0.01 |
Preparing shaft furnace oxidized pellets: uniformly mixing iron ore concentrate powder crushed and ground to 200 meshes and accounting for 60-80% of the iron ore concentrate powder, a binder and water according to the mass ratio of 100:1.0:6.5 by a mixer, and briquetting the mixture by a briquetting machine, wherein the briquetting machine is used for briquetting the mixture with too high or too low moisture and binder. Sieving the produced briquette by a sieving machine, conveying the sieved briquette 9-20mm into a drying kiln for drying at 120 ℃ for 10min, returning the briquette larger than or smaller than the granularity to grinding and briquetting, conveying the dried briquette into a 2-section preheating furnace for preheating, preheating at 600 ℃ for 5min in a 1-section preheating furnace and at 900 ℃ for 10min in a 2-section preheating furnace, conveying the briquette in the 2-section preheating furnace into a roasting furnace for roasting, and roasting at 1150 ℃ for 15 min. And (3) cooling the roasted blocks by a circular cooler, discharging the blocks out of the furnace, screening the blocks to obtain 8-20mm blocks, conveying the 8-20mm blocks to a workshop of the shaft furnace, and hoisting the blocks into a bin at the top of the shaft furnace. The briquettes are continuously added from the top of the shaft furnace, coal gas is introduced from the bottom of a reduction section of the shaft furnace, the temperature of the coal gas at an inlet of the shaft furnace is 810 ℃, the pressure in the furnace is controlled to be 0.2MPa, the iron ore briquettes stay in the reduction section for 5 hours, and the high-temperature coal gas and the briquettes from top to bottom are reduced and subjected to heat exchange, wherein the reduction principle is as follows:
2Fe2O3+CO(H2)＝Fe3O4+CO2(H2O) (1)
Fe3O4+CO(H2)＝3FeO+CO2(H2O) (2)
FeO+CO(H2)＝Fe+CO2(H2O) (3)
because the coal gas is not reformed by methane, the coal gas contains methane, water vapor and carbon dioxide, the following reactions also occur in the shaft furnace:
CH4+CO2＝CO+H2，CH4+H2O＝CO+H2
the reduced solid-state directly-reduced iron was discharged continuously without cooling in the cooling zone, and the main components and contents of the directly-reduced iron were as shown in table 8.
TABLE 8 reduced iron main components and contents%
| TFe | MFe | FeO | S | P | CaO | MgO | SiO2 | Al2O3 |
| 87.88 | 81.56 | 9.01 | 0.02 | 0.012 | 0.31 | 0.35 | 4.22 | 2.10 |
The reduced iron is continuously added into an electric arc furnace for steelmaking through a high-temperature conveyer belt, the tapping temperature is 600 ℃, the reduced iron is melted, reduced and refined after entering the electric furnace, and semi-coke (the mass ratio of the reduced iron to the semi-coke is 100:4) is added as a reducing agent after the smelting process, so that iron oxide in the reduced iron is reduced into metallic iron. In order to facilitate dephosphorization, the reducing agent is added in an amount to control the content of ferrous oxide in the slag to be 12-20%. In order to control the alkalinity of the slag to be 1.5-2.8, the adding amount ratio of the lime as a slagging and dephosphorizing agent and the direct reduced iron is 15: 100. According to the reduction and slagging principle of the ferrous oxide content in the electric furnace direct reduced iron: (FeO) + [ C]＝[Fe]+CO，(P2O5)+3(FeO)＝3(FeO.P2O5)，P2O5+4(CaO)＝(4CaO.P2O5) (ii) a In order to prevent rephosphorization, after dephosphorization is finished, slagging-off (CaO + SiO) is required2＝CaSiO3) After slagging off, molten steel alloying operation is carried out for removing oxygen, sulfur and other impurity components in the steel, and the content of all elements in the finished steel is ensured to meet the standard requirement.
Example 3
Drying the crushed and sieved coal with the granularity of 2-8mm and dolomite in a drying furnace, wherein the heat source of the dried coal is gas-based direct reduction shaft furnace top gas flue gas, the temperature of the shaft furnace top gas is 350 ℃, conveying the dried and dehydrated coal powder to a fluidized bed bin for later use, and adding the coal through a spiral feeder.
Firstly, raw material coal and a desulfurizer are fed into a feeder from a bin and are added into a fluidized bed, and the mass ratio of the coal to the desulfurizer is 100: 1.5. And (3) completely introducing a mixture of water vapor and pure oxygen from the bottom of the bed layer, wherein the molar ratio of the mixture of carbon in the coal powder and the water vapor and the pure oxygen in the production process is 1.15:1 for better coupling with the direct reduction process of the shaft furnace. The pressure in the bed was controlled at 0.8MPa and the bed temperature was 750 ℃. The contents of carbon dioxide and water vapor in the coal gas at the outlet of the fluidized bed are respectively 6.25 percent and 5.12 percent. The main principle of fluidized bed coal gasification is as follows:
C+H2O＝CO+H2，C+O2＝CO2，C+CO22CO, and methane and CnHm gas obtained by decomposition of volatile components, the main components and contents of the gas are shown in table 9.
TABLE 9 main components and contents of gas%
| Composition (I) | CO | H2 | CO2 | H2O | CH4 | CnHm |
| Content (wt.) | 36.10 | 45.44 | 6.25 | 5.12 | 6.17 | 0.92 |
The generated coal gas is directly conveyed to the shaft furnace to directly reduce the iron ore oxidized pellets without decarbonization, desulfurization, temperature reduction, dehydration and pressurization depressurization treatment. The main components and contents of iron ore and its oxidized pellets are shown in tables 10 and 11.
TABLE 10 iron ore main components and contents%
| TFe | Fe2O3 | FeO | CaO | MgO | SiO2 | Al2O3 | S | P |
| 68.55 | 69.11 | 26.00 | 0.22 | 0.35 | 2.76 | 1.49 | 0.04 | 0.07 |
TABLE 11 main component content of oxidized pellets%
| TFe | Fe2O3 | FeO | CaO | MgO | SiO2 | Al2O3 | S | P |
| 65.18 | 95.10 | 0.50 | 0.27 | 0.31 | 3.24 | 1.26 | 0.01 | 0.01 |
Preparing shaft furnace oxidized pellets: uniformly mixing iron ore concentrate powder which is crushed and ground to-200 meshes and accounts for 60-80% with a binder and water according to the ratio of 100:2.0:5 by a mixer, and pelletizing by a pelletizer, wherein the water content and the binder are too high and too low to be harmful to pelletizing. Sieving the pellets by a sieving machine, conveying the sieved pellets of 9-20mm to a drying kiln for drying at 120 ℃ for 10min, returning the pellets larger than or smaller than the granularity to grinding and pelletizing, conveying the dried pellets to 2 sections of preheating furnaces for preheating, preheating at 450 ℃ for 3min in a 1 section of preheating furnace and at 600 ℃ for 8min in a 2 section of preheating furnace, conveying the pellets in the 2 sections of preheating furnaces to a roasting furnace for roasting, and roasting at 1300 ℃ for 10 min. And cooling the roasted blocks by a circular cooler, discharging the blocks out of the furnace, screening out pellets of 8-20mm, conveying the pellets of 8-20mm to a workshop of the shaft furnace, and hoisting the pellets into a bin at the top of the shaft furnace. The pellets are continuously added from the top of the shaft furnace, coal gas is introduced from the bottom of a reduction section of the shaft furnace, the temperature of the coal gas at an inlet of the shaft furnace is 950 ℃, the pressure in the furnace is controlled to be 0.65MPa, the iron ore pellets stay for 5 hours in the reduction section, and the high-temperature coal gas and the pellets from top to bottom are subjected to reduction and heat exchange, wherein the reduction principle is as follows:
2Fe2O3+CO(H2)＝Fe3O4+CO2(H2O) (1)
Fe3O4+CO(H2)＝3FeO+CO2(H2O) (2)
FeO+CO(H2)＝Fe+CO2(H2O) (3)
the solid reduced iron reduced by the shaft furnace was discharged continuously without cooling in the cooling zone, and the main components and contents of the reduced iron were as shown in table 12.
TABLE 12 reduced iron main components and contents%
| TFe | MFe | FeO | S | P | CaO | MgO | SiO2 | Al2O3 |
| 89.86 | 82.67 | 9.25 | 0.01 | 0.014 | 0.30 | 0.49 | 4.41 | 2.15 |
The reduced iron is continuously added into an electric arc furnace for steelmaking through a high-temperature conveyer belt, the tapping temperature is 500 ℃, the reduced iron is melted, reduced and refined after entering the electric furnace, anthracite coal (the mass ratio of the reduced iron to the anthracite coal is 100:3) is added as a reducing agent after the smelting process, and iron oxide in the reduced iron is reduced into metallic iron. In order to facilitate dephosphorization, the reducing agent is added in an amount to control the content of ferrous oxide in the slag to be 12-20%. In order to control the alkalinity of the slag within the range of 1.5-2.8, the adding amount ratio of the limestone used as a slagging and dephosphorizing agent and the direct reduced iron is 13: 100. According to the reduction and slagging principle of the ferrous oxide content in the electric furnace direct reduced iron: (FeO) + [ C]＝[Fe]+CO，(P2O5)+3(FeO)＝3(FeO.P2O5)，P2O5+4(CaO)＝(4CaO.P2O5) (ii) a In order to prevent rephosphorization, after dephosphorization is finished, slagging-off (CaO + SiO) is required2＝CaSiO3) After slagging off, molten steel alloying operation is carried out for removing oxygen, sulfur and other impurity components in the steel, and the content of all elements in the finished steel is ensured to meet the standard requirement.
Example 4
Drying the crushed and sieved coal with the granularity of 2-8mm and dolomite in a drying furnace, wherein the heat source of the dried coal is gas-based direct reduction shaft furnace top gas flue gas, the temperature of the shaft furnace top gas is 550 ℃, conveying the dried and dehydrated coal powder to a fluidized bed bin for later use, and adding the coal through a spiral feeder.
Firstly, raw material coal and a desulfurizer are fed into a feeder from a bin and are added into a fluidized bed, and the mass ratio of the coal to the desulfurizer is 100: 4. And (3) completely introducing a mixture of water vapor and pure oxygen from the bottom of the bed layer, wherein the molar ratio of the mixture of carbon in the coal powder and the water vapor and the pure oxygen in the production process is 1.25:1 for better coupling with the direct reduction process of the shaft furnace. The pressure in the bed is controlled at 0.3MPa, and the temperature in the bed is 900 ℃. The contents of carbon dioxide and water vapor in the coal gas at the outlet of the fluidized bed are respectively 6.01 percent and 4.11 percent. The main principle of fluidized bed coal gasification is as follows:
C+H2O＝CO+H2，C+O2＝CO2，C+CO22CO, and methane and CnHm gas obtained by decomposition of volatile components, the main components and contents of the gas are shown in table 13.
Table 13 gas main components and contents%
| Composition (I) | CO | H2 | CO2 | H2O | CH4 | CnHm |
| Content (wt.) | 33.16 | 47.27 | 6.01 | 4.11 | 8.46 | 0.99 |
The produced coal gas does not need decarburization and desulfurization, cooling and dewatering and pressurization and depressurization treatment, and the outlet coal gas is heated by a radiant tube type heating furnace and then sent to a shaft furnace to directly reduce the iron ore oxidized pellets. The main components and contents of iron ore and its oxidized pellets are shown in tables 14 and 15.
TABLE 14 iron ore main components and contents%
| TFe | Fe2O3 | FeO | CaO | MgO | SiO2 | Al2O3 | S | P |
| 68.55 | 69.11 | 26.00 | 0.22 | 0.35 | 2.76 | 1.49 | 0.04 | 0.07 |
TABLE 15 main component content of oxidized pellets%
| TFe | Fe2O3 | FeO | CaO | MgO | SiO2 | Al2O3 | S | P |
| 65.13 | 90.24 | 0.49 | 0.25 | 0.32 | 3.21 | 1.27 | 0.01 | 0.01 |
Preparing shaft furnace oxidized pellets: uniformly mixing iron ore concentrate powder crushed and ground to-200 meshes accounting for 60-80% of the total weight of the iron ore concentrate powder, a binder and water according to the ratio of 100:0.8:10 by a mixer, and briquetting the mixture by a briquetting machine, wherein the water and the binder are too high and too low to be briquetted. Sieving the produced briquette by a sieving machine, conveying the sieved briquette 9-20mm into a drying kiln for drying at 200 ℃ for 6min, returning the briquette larger than or smaller than the granularity to grinding and briquetting, conveying the dried briquette into a 2-section preheating furnace for preheating, preheating at 550 ℃ for 6min in a 1-section preheating furnace and at 800 ℃ for 7min in a 2-section preheating furnace, conveying the briquette in the 2-section preheating furnace into a roasting furnace for roasting, and roasting at 1250 ℃ for 12 min. And (3) cooling the roasted blocks by a circular cooler, discharging the blocks out of the furnace, screening the blocks to obtain 8-20mm blocks, conveying the 8-20mm blocks to a workshop of the shaft furnace, and hoisting the blocks into a bin at the top of the shaft furnace. The briquettes are continuously added from the top of the shaft furnace, coal gas is introduced from the bottom of a reduction section of the shaft furnace, the temperature of the coal gas at an inlet of the shaft furnace is 750 ℃, the pressure in the furnace is controlled to be 0.2MPa, the iron ore briquettes stay for 9 hours in the reduction section, and the high-temperature coal gas and the briquettes from top to bottom are reduced and heat exchanged, wherein the reduction principle is as follows:
2Fe2O3+CO(H2)＝Fe3O4+CO2(H2O) (1)
Fe3O4+CO(H2)＝3FeO+CO2(H2O) (2)
FeO+CO(H2)＝Fe+CO2(H2O) (3)
the solid reduced iron reduced by the shaft furnace was directly and continuously discharged without being cooled by the cooling section, and the main components and contents of the directly reduced iron were as shown in table 16.
TABLE 16 reduced iron main components and contents%
| TFe | MFe | FeO | S | P | CaO | MgO | SiO2 | Al2O3 |
| 89.86 | 82.67 | 9.25 | 0.01 | 0.014 | 0.30 | 0.49 | 4.41 | 2.15 |
Continuously adding reduced iron into an electric arc furnace for steelmaking through a high-temperature conveyer belt, discharging at 800 ℃, melting, reducing and refining after entering the electric furnace, adding coke (the mass ratio of the reduced iron to the coke is 100:4) as a reducing agent after the smelting process, and reducing iron oxides in the reduced iron into goldBelongs to iron. In order to facilitate dephosphorization, the reducing agent is added in an amount to control the content of ferrous oxide in the slag to be 12-20%. In order to control the alkalinity of the slag within the range of 1.5-2.8, the adding amount ratio of the lime as a slagging and dephosphorizing agent and the direct reduced iron is 14: 100. According to the reduction and slagging principle of the ferrous oxide content in the electric furnace direct reduced iron: (FeO) + [ C]＝[Fe]+CO，(P2O5)+3(FeO)＝3(FeO.P2O5)，P2O5+4(CaO)＝(4CaO.P2O5) (ii) a In order to prevent rephosphorization, after dephosphorization is finished, slagging-off (CaO + SiO) is required2＝CaSiO3) After slagging off, molten steel alloying operation is carried out for removing oxygen, sulfur and other impurity components in the steel, and the content of all elements in the finished steel is ensured to meet the standard requirement.
The embodiment couples the processes of gas preparation of the fluidized bed, gas-based direct reduction and electric furnace steel making, thereby omitting the processes of cooling, washing, dedusting and heating of the gas prepared by the fluidized bed, reducing the system investment, fully utilizing the sensible heat of the gas, reducing the energy consumption of heating the gas of the shaft furnace, and avoiding the high-temperature corrosion of carbon dioxide or water vapor in the gas to the pipeline of the traditional heating furnace. The reduced iron is continuously and thermally conveyed to the electric furnace through the high-temperature conveyer belt, so that the power consumption is reduced. And better parameters are screened out, the optimal process of the whole flow is found out, and the optimal coupling of the production parameters among equipment is realized.
Finally, it should be noted that: it should be understood that the above examples are only for clearly illustrating the present invention and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the scope of the invention.
Claims (10)
1. A coupling system of fluidized bed gas making, gas-based reduction and electric furnace steelmaking is characterized by comprising a fluidized bed, a gas-based shaft furnace and an electric furnace; wherein,
the fluidized bed comprises an air distribution plate, a gas inlet, a first material inlet and a coal gas outlet, wherein the gas inlet is arranged at the bottom of a bed layer of the fluidized bed, the air distribution plate is arranged above the gas inlet, the coal gas outlet is arranged at the top of the fluidized bed, and the first material inlet is arranged above the air distribution plate;
the gas-based shaft furnace comprises a gas inlet, a second material inlet and a reduced iron outlet, wherein the gas inlet is arranged at the bottom of the reduction section of the gas-based shaft furnace and is connected with the gas outlet, and the second material inlet is arranged at the top of the gas-based shaft furnace;
the electric furnace comprises a reduced iron inlet and a steel tapping hole, and the reduced iron inlet is connected with the reduced iron outlet through a high-temperature conveying belt.
2. The system according to claim 1, further comprising an oxidation mass preparation unit, wherein the oxidation mass preparation unit is sequentially connected by a mixer, a forming unit, a screening machine, a drying kiln, a preheating furnace, a roasting furnace, a cooling unit, and a screening device, wherein the screening device comprises an oxidation mass outlet, and the oxidation mass outlet is connected with the second feed inlet of the gas-based shaft furnace.
3. The system of claim 1, further comprising a heating furnace disposed between the fluidized bed and the gas-based shaft furnace, the heating furnace being connected to a gas outlet of the fluidized bed and a gas inlet of the gas-based shaft furnace by gas conduits, respectively.
4. The system of claim 1, further comprising a coal oven having a first material outlet and a hot gas inlet, the first material outlet being connected to the first material inlet of the fluidized bed.
5. The system of claim 4, wherein said gas-based shaft furnace further comprises a flue gas outlet disposed at a top of said furnace, said flue gas outlet being connected to a hot gas inlet of said coal drying furnace.
6. A method for coupling fluidized bed gas making, gas-based reduction and electric furnace steelmaking by using the system is characterized by comprising the following steps:
a, fluidized bed gas making: adding a carbonaceous raw material and a desulfurizing agent into a fluidized bed from a first material inlet of the fluidized bed, introducing oxidizing gas from a gas inlet of the fluidized bed, and carrying out gasification reaction on the first material and the oxidizing gas to obtain coal gas; wherein the bed pressure of the fluidized bed is 0.25MPa-0.8MPa, and the bed temperature is 750-;
b, gas-based reduction: conveying the coal gas obtained in the step A to a gas-based shaft furnace through a coal gas inlet, putting an iron mineral material into the gas-based shaft furnace through a second material inlet, and performing reduction reaction and heat exchange on the coal gas and the iron mineral material to generate direct reduced iron; wherein the temperature of the coal gas at the coal gas inlet of the gas-based shaft furnace is 750-800 ℃, and the tapping temperature of the direct reduced iron is 500-800 ℃;
c, steel making: b, conveying the direct reduced iron obtained in the step B by using a high-temperature conveying belt, adding the direct reduced iron into an electric furnace through a reduced iron inlet of the electric furnace, and carrying out reduction smelting to obtain finished steel and furnace slag; wherein, a reducing agent and a slagging constituent are added in the smelting process.
7. The process of claim 6, wherein in step A, the molar ratio of carbon in the carbonaceous feedstock to the oxidizing gas is from 1.1 to 1.25: 1.
8. The method according to claim 6, wherein in step B, the furnace pressure of the gas-based shaft furnace is controlled to be 0.2MPa to 0.75 MPa.
9. The method according to claim 6, further comprising the step of preparing the iron ore into an oxidized briquette before the gas-based reduction; wherein, this step includes:
mixing the iron ore material with a binder and water in a mixer; conveying the obtained mixture to a forming unit and forming; conveying the obtained pellets or blocks into a sieving machine for sieving to obtain blocks with certain granularity; drying the block mass with certain granularity by using a drying kiln; sending the dried briquette to a preheating furnace for preheating to obtain a preheated briquette; the preheated briquette is sent to a roasting furnace for oxidizing roasting; and cooling the pellets obtained after roasting by a cooling unit, screening by a screening device to obtain the oxidized pellets with a certain granularity, and conveying the oxidized pellets to the gas-based shaft furnace for reaction.
10. The method of claim 6, wherein in step C, the ferrous oxide content of the slag is 12-20%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710606854.8A CN107299175A (en) | 2017-07-24 | 2017-07-24 | A kind of system and method for fluid bed gas, gas-based reduction and electric furnace steel making coupling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710606854.8A CN107299175A (en) | 2017-07-24 | 2017-07-24 | A kind of system and method for fluid bed gas, gas-based reduction and electric furnace steel making coupling |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN107299175A true CN107299175A (en) | 2017-10-27 |
Family
ID=60133544
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710606854.8A Pending CN107299175A (en) | 2017-07-24 | 2017-07-24 | A kind of system and method for fluid bed gas, gas-based reduction and electric furnace steel making coupling |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107299175A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109355108A (en) * | 2018-09-18 | 2019-02-19 | 华中科技大学 | A concentrated solar energy gasification biomass system for synthesis gas preparation and metal smelting |
| CN111961784A (en) * | 2020-08-31 | 2020-11-20 | 山东大学 | Method and system for reduction reaction of iron ore powder in bubbling bed |
| CN114921602A (en) * | 2022-06-16 | 2022-08-19 | 山东省红森林新材料科技有限公司 | Ultrashort flow steelmaking device system |
| CN115516115A (en) * | 2020-03-20 | 2022-12-23 | 技术资源有限公司 | Biomass direct reduced iron |
| CN115522007A (en) * | 2021-06-25 | 2022-12-27 | 中晋冶金科技有限公司 | Production process of hot pellet reduced iron |
| TWI802162B (en) * | 2021-03-31 | 2023-05-11 | 日商Ｊｆｅ鋼鐵股份有限公司 | Operation method of reduction furnace |
| CN116356097A (en) * | 2023-04-13 | 2023-06-30 | 中冶赛迪工程技术股份有限公司 | Process and system for producing direct reduced iron using electric furnace flue gas and hydrogen-rich gas |
| CN116926258A (en) * | 2023-07-14 | 2023-10-24 | 太原理工大学建筑设计研究院有限公司 | Method for directly reducing iron by gas-based shaft furnace |
| US12276002B2 (en) | 2019-12-25 | 2025-04-15 | Kobe Steel, Ltd. | Molten steel production method |
-
2017
- 2017-07-24 CN CN201710606854.8A patent/CN107299175A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109355108A (en) * | 2018-09-18 | 2019-02-19 | 华中科技大学 | A concentrated solar energy gasification biomass system for synthesis gas preparation and metal smelting |
| CN109355108B (en) * | 2018-09-18 | 2020-02-21 | 华中科技大学 | A concentrated solar energy gasification biomass system for synthesis gas preparation and metal smelting |
| US12276002B2 (en) | 2019-12-25 | 2025-04-15 | Kobe Steel, Ltd. | Molten steel production method |
| CN115516115A (en) * | 2020-03-20 | 2022-12-23 | 技术资源有限公司 | Biomass direct reduced iron |
| CN111961784A (en) * | 2020-08-31 | 2020-11-20 | 山东大学 | Method and system for reduction reaction of iron ore powder in bubbling bed |
| TWI802162B (en) * | 2021-03-31 | 2023-05-11 | 日商Ｊｆｅ鋼鐵股份有限公司 | Operation method of reduction furnace |
| CN115522007A (en) * | 2021-06-25 | 2022-12-27 | 中晋冶金科技有限公司 | Production process of hot pellet reduced iron |
| CN115522007B (en) * | 2021-06-25 | 2024-07-12 | 中晋冶金科技有限公司 | Production process of hot-pellet reduced iron |
| CN114921602A (en) * | 2022-06-16 | 2022-08-19 | 山东省红森林新材料科技有限公司 | Ultrashort flow steelmaking device system |
| CN114921602B (en) * | 2022-06-16 | 2023-10-10 | 山东省红森林新材料科技有限公司 | Ultrashort flow steelmaking device system |
| CN116356097A (en) * | 2023-04-13 | 2023-06-30 | 中冶赛迪工程技术股份有限公司 | Process and system for producing direct reduced iron using electric furnace flue gas and hydrogen-rich gas |
| CN116926258A (en) * | 2023-07-14 | 2023-10-24 | 太原理工大学建筑设计研究院有限公司 | Method for directly reducing iron by gas-based shaft furnace |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107299175A (en) | A kind of system and method for fluid bed gas, gas-based reduction and electric furnace steel making coupling | |
| CN115491455B (en) | Prereduced pellet preparation device and prereduced pellet preparation method based on belt roasting machine | |
| CN110923387B (en) | A system and method for stepwise waste heat recovery and direct reduction of iron-containing metallurgical slag particles | |
| CN104212930B (en) | A kind of BAOSHEREX iron-smelting process of two-step smelting molten iron | |
| CN101519703B (en) | A Low Coke Ratio Blast Furnace Ironmaking Process | |
| CN102057060A (en) | Method and device for producing primary products of pig iron or liquid steel | |
| CN105838838B (en) | Method for preparing pure steel by coal gas direct reduction one-step method | |
| Kurunov | The direct production of iron and alternatives to the blast furnace in iron metallurgy for the 21st century | |
| CN105112663A (en) | Combined production process for high-carbon ferro-chrome and semi-coke | |
| CN101928800A (en) | Method for directly reducing carbon-bearing ferromagnetic metal pellets by adopting sensible heat of raw gases | |
| WO2024221684A1 (en) | Method and device for treating nickel laterite ore leaching residue | |
| CN107447068A (en) | A kind of method and system of coal pyrolysis gas reduction schreyerite | |
| JP4427295B2 (en) | Reducing gas desulfurization method, blast furnace operating method and reducing gas utilization method | |
| CN107118807B (en) | System and method for preparing reducing gas by lignite double-bed gasification | |
| CN103667565B (en) | Middle low-rank coal vaporizing system standby reduction air cooling send fluidized-bed to smelt novel method and system | |
| CN102127610B (en) | Ironmaking equipment and process for direct smelting reduction of iron ore | |
| KR101607254B1 (en) | Combiner Ironmaking facilities | |
| CN207130291U (en) | A kind of system of fluid bed gas, gas-based reduction and electric furnace steel making coupling | |
| CN101463404A (en) | Production process for producing spongy iron by dry coal powder gasification high furnace | |
| CN103667568B (en) | Middle low-rank coal vaporizing system is for reducing gas moving-bed novel process for smelting and system | |
| CN102181776A (en) | Technique and device for producing high-grade nickel and stainless steel by reduction pelletization | |
| CN108048611A (en) | A kind of system and method for no coal method production ferrochrome | |
| CN107267701A (en) | A kind of pyrolysis of coal, pyrolysis gas heating and the system and method for schreyerite reduction coupling | |
| CN223620410U (en) | System for high-efficient utilization of iron-making energy based on B-MIF smelting reduction | |
| CN207738786U (en) | A kind of system of no coal method production ferrochrome |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |