WO2021035821A1

WO2021035821A1 - Cyclone flashing-speed reduction direct steelmaking system and process

Info

Publication number: WO2021035821A1
Application number: PCT/CN2019/105867
Authority: WO
Inventors: 李琳; 李明明; 杨星; 邹宗树; 邵磊; 李强
Original assignee: 东北大学
Priority date: 2019-08-30
Filing date: 2019-09-16
Publication date: 2021-03-04
Also published as: CN110438277A; CN110438277B

Abstract

Provided are a cyclone flashing-speed reduction direct steelmaking system and process. The system comprises a carbon monoxide preparation device, a cyclone flashing-speed reduction furnace, an electric heating smelting separation furnace and a piece of tail gas post-treatment equipment, wherein the piece of tail gas post-treatment equipment comprises a pre-heating/pre-reduction device, a tail gas dedusting purification device, a heat exchanger and a tail gas separation device. The process comprises carrying out electrochemical reduction on carbon dioxide to prepare carbon monoxide and oxygen; spraying the carbon monoxide, the oxygen, an iron ore powder and a flux into a cyclone flashing-speed reduction furnace, and carrying out reduction at 900 to 1500℃ to obtain pre-reduced iron powder/iron drops with a metallization ratio of larger than 70%; introducing same into an electric heating smelting separation furnace so as to carry out smelting separation and final reduction; sequentially pre-heating/pre-reducing the iron ore powder and the flux through reduced and smelted tail gas, dedusting, pre-heating the oxygen, and separating same to obtain carbon monoxide and carbon dioxide; and returning same to a cyclone furnace and a carbon dioxide reduction device for recycling, respectively. The process uses electric energy for smelting and does not rely on fossil fuels, the carbon monoxide is recycled, no pollutant and carbon dioxide is discharged in the process, and clean smelting is realized.

Description

Cyclone flash reduction direct steelmaking system and process

Technical field

The invention belongs to the technical field of iron and steel metallurgy, and relates to a non-blast furnace ironmaking process, in particular to a cyclone flash reduction direct steelmaking system and process.

Background technique

Sintering → blast furnace → converter is the main process of crude steel production at present. This process integrates four process links of sintering (or pelletizing), coking, blast furnace ironmaking and converter steelmaking. It has a long production process, high energy consumption, and a strong dependence on fossils. Fuel resources and serious environmental pollution and other shortcomings. At a time when global environmental pollution and resource and energy shortages are becoming more and more serious, the implementation of energy conservation and emission reduction and the implementation of cleaner production have become the only way for the sustainable development of the global steel industry.

In view of the high pollution and high energy consumption of the traditional blast furnace ironmaking process, smelting reduction ironmaking technology can reduce the dependence on high pollution and high energy consumption processes such as agglomeration, sintering, and coking. Important technological approaches for waste gas and cleaner production, such as COREX, FINEX and HIsarna processes. The COREX method uses the upper pre-reduction shaft furnace to perform the pre-reduction of iron ore to obtain metallized pellets (DRI) with a metallization rate of 70% to 90%, and then send the DRI to the lower melting gasifier for final reduction. In the production process of this process, lump ore, pellets, sintered ore and some coke are still needed to maintain the furnace condition. The FINEX process uses fine ore as the raw material, and uses a multi-stage fluidized reactor to complete the pre-reduction of iron ore to obtain reduced iron powder with a metallization rate of about 90%. The reduced iron powder and pulverized coal are heated to agglomerate and added as furnace charge for melting The gasification furnace performs smelting final reduction. The HIsarna process uses fine ore as the main raw material and uses a cyclone melting furnace to flash smelt the fine ore. The fine ore, flux, and coal powder are sprayed into the cyclone melting furnace along the tangential direction of the furnace body with oxygen as the carrier, and the fine ore is in motion. It is reduced and melted, and then flows along the furnace wall and drips into the smelting reduction furnace for final reduction.

Patent CN101117650A proposes a method of smelting reduction and rapid pre-reduction of fine iron ore powder. The micron-sized iron ore powder is pre-reduced in a conveyor reactor or a fast fluidized bed at 580-750°C, and the pre-reduction rate is 70%-85%. The iron material is introduced into the melting gasifier through briquetting or powder spraying for final reduction. Patent CN102586527A proposes a new process for hydrogen-carbon smelting reduction ironmaking. After iron ore powder is preheated and reduced, hydrogen and coal powder are used for smelting reduction. The patents CN101906501A, CN101260448A, and CN108374067A propose a direct steelmaking process using fine ore and coal oxygen. After pre-reduction, iron ore powder is sprayed with pulverized coal and oxygen into the steelmaking furnace for steelmaking.

In summary, the current smelting reduction/direct steelmaking method can achieve the emission reduction target of steel production to a certain extent, but its smelting process still relies on coal-based reductants, and the reduction process emits large amounts of greenhouse gases and pollutants. Moreover, the energy required for the production process comes from non-renewable resources such as fossil fuels, which cannot effectively solve the huge energy consumption problem in the steel production process.

Summary of the invention

technical problem

The solution to the problem

Technical solutions

The technical task of the present invention is to provide a cyclone flash reduction direct steelmaking system and process in view of the above shortcomings of the prior art.

In one aspect of the present invention, a cyclone flash reduction direct steelmaking system is provided. The system includes: a carbon monoxide preparation device, a cyclone flash reduction furnace, an electric melting furnace, and exhaust gas post-treatment equipment. The exhaust gas post-treatment equipment includes preheating /Pre-reduction device, exhaust dust purification device, heat exchanger and exhaust separation device;

The carbon monoxide preparation device includes a carbon dioxide reduction reactor, a carbon monoxide storage tank and an oxygen storage tank, and the carbon dioxide reduction reactor is connected to the carbon monoxide storage tank and the oxygen storage tank through a pipeline;

The cyclone flash reduction furnace is provided with a feed inlet, a carbon monoxide nozzle, and a tail gas outlet, the tail gas outlet is arranged on the top of the furnace body, the feed inlet is arranged on the upper part of the furnace wall, and the carbon monoxide nozzle is arranged below the feed inlet On the furnace wall of, the carbon monoxide nozzle is connected to the carbon monoxide storage tank through a pipe, and the bottom of the cyclone flash reduction furnace is connected to the electric melting furnace;

The electric melting furnace is provided with an electrode, a steel tapping port, a slag tapping port and a bottom blowing element, and the bottom blowing element is connected to a carbon monoxide storage tank through a pipeline;

The preheating/pre-reduction device is provided with an air inlet, an air outlet, a material inlet, and a material outlet. The air inlet is connected to the tail gas outlet of the cyclone flash reduction furnace, and the air outlet is connected to a dust removal and purification device. The feed port is used to add iron ore powder and flux powder, and the feed port is connected to the feed port of the cyclone flash reduction furnace through a feed pipe;

The dust removal and purification device has a tail gas inlet, a tail gas outlet, and a dust removal discharge port, the tail gas inlet is connected to a preheating/prereduction device, the tail gas outlet is connected to a heat exchanger, and the dust removal ash discharge port is connected to a feed pipe ；

The heat exchanger has a first air inlet, a first air outlet, a second air inlet, and a second air outlet. The first air inlet is connected to the exhaust outlet of the dust removal and purification device, and the first air outlet is connected to The tail gas separation device is connected, the second air inlet is connected with the oxygen storage tank pipeline, and the second air outlet is connected with the feed pipeline;

The inlet end of the tail gas separation device is connected to a heat exchanger, and the outlet end is respectively connected to a carbon dioxide reduction reactor and a carbon monoxide storage tank through a pipeline.

The pipeline connecting the oxygen storage tank and the heat exchanger is provided with an oxygen flow regulating valve, the carbon monoxide storage tank is connected to the carbon monoxide nozzle, and the carbon monoxide storage tank is connected to the bottom blowing element of the electric melting furnace. All are equipped with carbon monoxide flow regulating valve.

Further, the feed inlet of the cyclone flash reduction furnace is arranged along the tangential direction of the furnace body.

Further, the inlet of the preheating/prereduction device is in communication with the iron ore powder feed hopper and the flux powder feed hopper.

Further, the preheating/prereduction device adopts a single or multiple fluidized bed reactors connected in series, and the tail gas separation device adopts adsorption and membrane separation equipment.

Further, at least one bottom blowing element may be any one of a nozzle or a breathable brick.

Another aspect of the present invention provides a cyclone flash reduction direct steelmaking process based on the above system. The process includes the following steps:

Step 1. Feed carbon dioxide into the carbon dioxide reduction reactor and perform electrochemical reduction to obtain pure carbon monoxide and oxygen. The purity of carbon monoxide is greater than 99%, and the purity of oxygen is greater than 99%. The carbon monoxide is transported to the carbon monoxide storage tank through the pipeline, and the oxygen is transported to the oxygen through the pipeline. Storage tank;

Step 2. The oxygen in the oxygen storage tank enters the heat exchanger to obtain the preheated oxygen; the iron ore powder and the flux powder enter the preheating/prereduction device to obtain the preheating/prereduction powder; the powder and the preheating oxygen are together Inject into the cyclone flash reduction furnace, while the carbon monoxide nozzle injects carbon monoxide to control the temperature in the furnace to 900～1500℃; the powder and carbon monoxide undergo a reduction reaction during the countercurrent movement in the cyclone furnace, and the metallization rate is more than 70%. Pre-reduced iron powder/iron droplets and pre-reduced tail gas;

Step 3. The pre-reduced iron powder/iron droplets formed in the cyclone flash reduction furnace directly fall into the electric melting furnace connected to the lower part due to gravity during the rotating movement along the furnace wall, and the electric heating melting furnace is controlled by the electrode heating The temperature is 1600～1750℃, the pre-reduced iron powder/iron droplets are electrothermally fused; at the same time, carbon monoxide is blown at the bottom, the molten pool is stirred and the melting is finalized, and the carbon monoxide blowing intensity is 0.01～0.2m ³ /(tFe·min) ; Carry out the continuous steelmaking process to obtain molten steel, slag and smelting tail gas. The molten slag and molten steel are discharged continuously or intermittently from the slag tap and the steel tap;

Step 4. The reduction tail gas produced in the cyclone flash reduction furnace and the smelting tail gas in the electric furnace are discharged from the tail gas outlet and enter the tail gas post-processing equipment; first, the high-temperature dust-containing tail gas is passed through the preheating/prereduction device, and the waste heat is used for preheating/prereducing Iron ore powder and flux powder, the cooled tail gas is sent to the dust removal purification device, after purification and dust removal, purified tail gas and dust removal ash are obtained, and the dust removal ash is returned to the cyclone flash reduction furnace, and the purified tail gas enters the heat exchanger for waste heat utilization and preheating The oxygen enters the tail gas separation device after cooling down to separate carbon monoxide and carbon dioxide. The carbon monoxide is transported to the carbon monoxide storage tank through the pipeline, and returned to the cyclone flash reduction furnace and the electric melting furnace as the reducing gas for recycling, and the carbon dioxide is transported to the carbon dioxide through the pipeline Reduce the reactor and recycle it.

Further, the flux powder in step 2 is one or more of the steelmaking slagging agent lime, fluorite, and dolomite, and the total iron TFe content of the iron ore powder is ≥50wt%; iron ore powder and flux powder The average particle size is less than 2mm.

Further, the mass ratio of iron ore powder to oxygen entering the cyclone flash reduction furnace in step 2 is 1:(1-9).

Further, the amount of flux added in step 2 is controlled so that the binary basicity of the slag in the electric melting furnace is 1.0-3.0.

Further, in the step 2, the volume ratio of oxygen blown from the feed port to carbon monoxide blown from the carbon monoxide nozzle is (1-9):100.

The present invention provides a cyclone flash reduction direct steelmaking system and process. The system uses a carbon dioxide reduction reactor, a cyclone flash reduction furnace, and an electric melting furnace as the main equipment, and uses the carbon dioxide electrochemical reduction method to prepare the reducing gas carbon monoxide. Obtain additional gas oxygen; oxygen and iron-containing powders are sprayed into the cyclone furnace from the upper feed port of the cyclone flash reduction furnace along the tangential direction of the furnace body, while the reducing gas carbon monoxide is blown in from below the feed port, and part of the carbon monoxide burns and emits heat To provide part of the heat in the furnace, the gas-solid two-phase reduction reaction occurs during the countercurrent movement in the cyclone flash reduction furnace to obtain pre-reduced iron powder/iron droplets with a metallization rate of >70%; pre-reduced iron powder/iron droplets Drop into the electric melting sub-furnace connected to the bottom of the cyclone flash reduction furnace for electro-thermal melting. At the same time, carbon monoxide is sprayed from the bottom of the electric melting sub-furnace for molten pool stirring and smelting final reduction to achieve continuous steelmaking. Steel and slag are separated from each other. Discharge from steel tap and slag tap; high temperature reduction and smelting tail gas preheating/pre-reduction of iron ore powder and flux powder, and after dust removal and purification, the dust removal ash returns to the cyclone flash reduction furnace, and the purified tail gas enters the heat exchanger to use the waste heat The oxygen/carbon monoxide is preheated, and the low-temperature purification tail gas is separated to obtain carbon dioxide and carbon monoxide. The carbon dioxide is returned to the carbon dioxide reduction reactor, and the carbon monoxide is sent to the carbon monoxide storage tank to realize resource recycling. The new process completely uses electricity for smelting, avoiding the use of non-renewable energy sources such as fossil fuels. The reducing gas carbon monoxide is recycled during the production process. Not only does the process emit no greenhouse gases and pollutants, it achieves clean production, but also uses carbon dioxide to produce carbon monoxide. , Can realize the resource utilization of carbon dioxide.

The beneficial effects of the invention

Beneficial effect

Compared with the prior art, the present invention has the following beneficial effects:

(1) Compared with the traditional steel smelting process, the present invention completely uses electric energy as the energy for the smelting process, replacing non-renewable resources such as coal and other fossil fuels; electric energy can be generated by renewable and clean energy such as nuclear energy, solar energy, and biomass energy. , Is conducive to alleviating the problem of energy shortage;

(2) The reducing gas carbon monoxide of the present invention is recycled during the production process without carbon dioxide and pollutant emissions, which not only realizes clean production, but also uses carbon dioxide electrochemical reduction method to prepare reducing gas, which can realize the resource utilization of carbon dioxide;

(3) The present invention makes full use of fine ore resources, gets rid of coking, sintering, pelletizing and other processes, does not require converter decarburization, thereby simplifying the steelmaking process, and is expected to improve the high pollution and high energy consumption problems caused by traditional smelting processes;

(4) The present invention uses a cyclone furnace to perform the pre-reduction of iron ore powder. The iron ore powder moves downward along the furnace wall in a circular rotation in the cyclone furnace, which can prolong the residence time of the powder in the furnace and the contact time with the reducing gas. , Is conducive to increase the reduction rate.

Brief description of the drawings

Description of the drawings

Figure 1 is a schematic diagram of the system structure of the present invention;

Reference signs: 1-carbon dioxide reduction reactor, 2-carbon monoxide storage tank, 3-oxygen storage tank, 4-iron ore powder feed hopper, 5-flux powder feed hopper, 6-cyclone flash reduction furnace, 7- Electric melting furnace, 8-cyclone flash reduction furnace oxygen flow control valve, 9-cyclone flash reduction furnace carbon monoxide flow control valve, 10-electric melting furnace carbon monoxide bottom blowing flow control valve, 11-preheating/pre-reduction device , 12- Dust removal and purification device, 13- heat exchanger; 14- tail gas separation device, 15- feed pipeline;

Among them, the cyclone flash reduction furnace includes: 601-feeding port, 602-carbon monoxide nozzle, 603-exhaust gas outlet;

Among them, the electric melting furnace includes: 701-electrode, 702-bottom blowing element, 703-steel outlet, 704-slag outlet;

Among them, the heat exchanger includes, 1301-first air inlet, 1302-first air outlet, 1303-second air inlet, 1304-second air outlet;

A-iron ore powder, B-flux powder, C-carbon dioxide, D-carbon monoxide, E-oxygen, F-slag, G-molten steel, H-tail gas, I-preheated/pre-reduced powder, J-high temperature containing Dust exhaust, K-dust removal;

Figure 2 is a process flow diagram of the present invention.

Invention embodiment

Embodiments of the present invention

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not used to limit the present invention.

As shown in Figure 1, the present invention provides a cyclone flash reduction direct steelmaking system, which includes: a carbon monoxide preparation device, a cyclone flash reduction furnace, an electric melting furnace, and exhaust gas after-treatment equipment, the exhaust gas after-treatment equipment Including preheating/pre-reduction device, exhaust dust removal and purification device, heat exchanger and exhaust separation device;

The carbon monoxide preparation device includes a carbon dioxide reduction reactor 1, a carbon monoxide storage tank 2 and an oxygen storage tank 3. The carbon dioxide reduction reactor is connected to the carbon monoxide storage tank and the oxygen storage tank through a pipeline;

The cyclone flash reduction furnace 6 is provided with a feed inlet 601, a carbon monoxide nozzle 602, and a tail gas outlet 603. The tail gas outlet is set on the top of the furnace body, and the feed inlet is set on the upper part of the furnace wall, and is reduced along the cyclone flash speed. The furnace is arranged tangentially, the carbon monoxide nozzle is arranged on the furnace wall below the inlet, the carbon monoxide nozzle is connected to the carbon monoxide storage tank through a pipe, and the pipe is provided with a carbon monoxide flow regulating valve 9 to control the flow. The cyclone flash reduction The bottom of the furnace is connected with the electric melting furnace;

The electrothermal melting sub-furnace 7 is provided with an electrode 701, a bottom blowing element 702, a tapping port 703 and a slag tapping port 704. The tapping port is set at the bottom of the furnace wall, and the slag tapping port is set below the slag layer. The bottom blowing element is connected to the carbon monoxide storage tank through a pipeline, and the flow is controlled by a carbon monoxide flow regulating valve 10 arranged on the pipeline;

The preheating/prereduction device 11 adopts a single or multiple fluidized bed reactors connected in series, and is provided with an air inlet, an air outlet, a material inlet, and a material outlet. The air inlet and the cyclone flash reduction furnace tail gas outlet Connected, the air outlet is connected to the dust removal and purification device 12, the inlet is used to add iron ore powder and flux powder, and the inlet is connected with the iron ore powder feed hopper 4 and the flux powder feed hopper 5, so The discharge port is connected to the feed port of the cyclone flash reduction furnace through a feed pipe 15;

The dust removal and purification device has a tail gas inlet, a tail gas outlet, and a dust removal discharge port. The tail gas inlet is connected to a preheating/prereduction device, the tail gas outlet is connected to the heat exchanger 13, and the dust removal ash discharge port is connected to a feed pipe Connected

The heat exchanger has a first air inlet 1301, a first air outlet 1302, a second air inlet 1303, and a second air outlet 1304. The first air inlet is connected to the exhaust outlet of the dust removal and purification device. An air outlet is connected to the tail gas separation device 14, the second air inlet is connected to the oxygen storage tank pipeline, and the flow is controlled by an oxygen flow regulating valve 8 set on the pipeline, and the second air outlet is connected to the feed pipeline;

The tail gas separation device can adopt adsorption and membrane separation equipment, the inlet end is connected with a heat exchanger, and the outlet end is respectively connected with a carbon dioxide reduction reactor and a carbon monoxide storage tank through a pipeline.

Wherein, at least one bottom blowing element can be any one of a nozzle or a breathable brick.

Step 1. Feed carbon dioxide C into the carbon dioxide reduction reactor and perform electrochemical reduction to obtain pure carbon monoxide D and oxygen E. The purity of carbon monoxide is greater than 99%, and the purity of oxygen is greater than 99%. The carbon monoxide is transported to the carbon monoxide storage tank through the pipeline, and the oxygen is passed through the pipeline. Transport to the oxygen storage tank;

Step 2. The oxygen in the oxygen storage tank enters the heat exchanger, and the high-temperature purified tail gas is preheated to obtain pre-heated oxygen; iron ore powder A and flux powder B enter the preheating/pre-reduction device from the feed hopper, and pass the high-temperature tail gas Preheating/pre-reduction to obtain pre-heating/pre-reduction powder I and dust-containing tail gas; the powder and pre-heating oxygen are blown into the cyclone furnace along the tangential direction of the furnace body from the upper feed port of the cyclone flash reduction furnace together with the pre-heating oxygen, and the carbon monoxide tank is at the same time The carbon monoxide in the carbon monoxide is blown into the cyclone flash reduction furnace from the carbon monoxide nozzle located below the feed port. The temperature in the furnace is controlled at 900～1500℃; the powder and carbon monoxide undergo a reduction reaction during the countercurrent movement in the cyclone furnace to obtain the metallization rate. It is more than 70% of the pre-reduced iron powder/iron droplets and the pre-reduced tail gas; at the same time, part of the carbon monoxide and oxygen undergo a combustion reaction to release heat, which provides part of the physical heat for the reduction process in the furnace;

Wherein, the flux powder is one or more of the steelmaking slagging agent lime, fluorite, and dolomite, the total iron TFe content of the iron ore powder is ≥50wt%; the average particle size of the iron ore powder and the flux powder are both ≤2mm, The mass ratio of iron ore powder to oxygen entering the cyclone flash reduction furnace is 1:(1-9), and the ratio of oxygen blown from the feed port to the volume of carbon monoxide blown from the carbon monoxide nozzle is (1-9):100;

Step 3. The pre-reduced iron powder/iron droplets formed in the cyclone flash reduction furnace fall directly into the electric melting furnace connected to the lower part of the cyclone flash reduction furnace during the rotating movement along the furnace wall due to gravity, and the electric melting furnace passes through Electrode heating, the furnace temperature is controlled at 1600～1750℃, and the pre-reduced iron powder/iron droplets are electrothermally separated; at the same time, carbon monoxide is blown into the molten pool from the electrothermal melting sub-furnace, the molten pool is stirred and melted for final reduction, and carbon monoxide is sprayed The strength is 0.01～0.2m ³ /(tFe·min); the continuous steelmaking process is carried out to obtain molten steel G, slag F and smelting tail gas. The slag and molten steel are discharged continuously or intermittently from the slag outlet and the steel outlet respectively;

Step 4. The reduction tail gas produced in the cyclone flash reduction furnace and the smelting tail gas in the electric melting furnace are discharged from the tail gas outlet located at the top of the cyclone flash reduction furnace, and enter the tail gas post-treatment equipment; first, the tail gas H is preheated/pre-reduced The device uses waste heat to preheat/pre-reduce iron ore powder and flux powder. The high-temperature dust-containing tail gas J is sent to the dust removal purification device. After purification and dust removal, purified tail gas and dust removal ash K are obtained, and the dust removal ash is returned to the cyclone flash reduction furnace to purify the tail gas It enters the heat exchanger for waste heat utilization, preheats the oxygen, and enters the tail gas separator after cooling to separate carbon monoxide and carbon dioxide. The carbon monoxide is transported to the carbon monoxide storage tank through the pipeline, and is returned as the reducing gas to the cyclone flash reduction furnace and the electric melting point. The furnace is recycled, and the carbon dioxide is transported to the carbon dioxide reduction reactor through the pipeline for recycling.

Wherein, the process further includes controlling the amount of flux powder added in step 2 so that the binary basicity of the slag in the electric melting furnace is 1.0-3.0.

Wherein, the temperature in the cyclone flash reduction furnace is controlled at 900-1500°C, and part of the heat in the furnace comes from the exothermic carbon monoxide combustion in the furnace, and part comes from the heating of the electric melting furnace at the lower part of the cyclone furnace.

Wherein, the temperature of the electric heating furnace is controlled at 1600-1750°C, and the heat is provided by electric energy.

Wherein, in the cyclone flash reduction direct steelmaking process, the energy required by the entire system (including carbon monoxide production system and electric melting furnace system) comes from electric energy, and the electric energy generation method can be any non-fossil fuel power generation such as nuclear energy, solar energy, hydraulic power, etc. .

Wherein, the carbon dioxide in the carbon dioxide reduction reactor comes from the internal circulation, and the loss part is supplied from the outside.

Example 1

A cyclone flash reduction direct steelmaking process using the above-mentioned system and process, the specific process parameters involved in each step are as follows:

Step 1. Feed carbon dioxide into the carbon dioxide reduction reactor and perform electrochemical reduction to obtain pure carbon monoxide and oxygen. The purity of carbon monoxide is greater than 99%, and the purity of oxygen is greater than 99%;

Step 2. Add iron ore powder and flux powder to the preheating/pre-reduction device. The total iron TFe content of the iron ore powder is 50wt% and the average particle size is 2mm. The iron ore powder and flux powder are blown into the cyclone together with the preheated oxygen. Flash reduction furnace, in which the mass ratio of iron ore powder to oxygen is 1:3, carbon monoxide is blown in, the volume ratio of carbon monoxide nozzle injection to oxygen injection is 100:3, and the temperature in the reduction furnace is controlled to 900～1500 ℃; the powder and carbon monoxide undergo a reduction reaction during the countercurrent movement in the cyclone flash reduction furnace to obtain pre-reduced iron powder/iron droplets and pre-reduced tail gas with a metallization rate> 70%;

Step 3. Control the temperature in the electric melting furnace to 1750℃, and control the amount of flux added so that the binary alkalinity of the slag in the electric furnace is 3.0, the slagging agent is lime powder, the average particle size is 2mm, and the bottom of the electric melting furnace is sprayed. Blowing strength ^{of carbon monoxide of 0.1m 3} /(tFe·min); stirring the molten pool while completing the final reduction of melting, the molten steel and molten slag obtained from the final reduction are discharged from the tap and the slag outlet respectively; the produced molten steel The molten steel with a mass fraction of C of 0.01% to 0.40% and a temperature of 1750°C is used in the subsequent refining process to produce ultra-pure steel;

Step 4. Reduction and smelting tail gas is preheated/prereduced iron ore powder and flux powder in sequence, dust is removed, oxygen is preheated, and separated to obtain carbon monoxide and carbon dioxide, which are returned to the cyclone flash reduction furnace and carbon dioxide reduction device for recycling.

Example 2

Step 2. Add iron ore powder and flux to the preheating/pre-reduction device. The total iron TFe content of the iron ore powder is 60wt% and the average particle size is 1mm. The iron ore powder and flux powder are blown into the cyclone flash together with the preheated oxygen. Rapid reduction furnace, in which the mass ratio of iron ore powder to oxygen is 1:5, carbon monoxide is blown in, the volume ratio of carbon monoxide nozzle injection to oxygen injection volume is 100:5, and the temperature in the reduction furnace is controlled to 900～1500℃ ; The powder and carbon monoxide undergo a reduction reaction during the countercurrent movement in the furnace to obtain pre-reduced iron powder/iron droplets and pre-reduced tail gas with a metallization rate> 70%;

Step 3. Control the temperature in the electric melting furnace to 1700℃, and at the same time control the amount of flux added so that the binary alkalinity of the slag in the electric furnace is 2.0, the slagging agent is lime powder, the average particle size is 1mm, and the bottom of the electric melting furnace is sprayed. Blowing strength ^{of carbon monoxide of 0.05m 3} /(tFe·min); stirring the molten pool while completing the final reduction of melting, the molten steel and slag obtained from the final reduction are discharged from the tap and slag outlet respectively; the produced molten steel is The molten steel with a mass fraction of C of 0.01% to 0.40% and a temperature of 1700°C is used in the subsequent refining process to produce ultra-pure steel;

Example 3

Step 2. Add iron ore powder and flux to the preheating/pre-reduction device. The total iron TFe content of the iron ore powder is 68wt% and the average particle size is 0.5mm. The iron ore powder and flux powder are blown into the cyclone together with the preheated oxygen. Flash reduction furnace, in which the mass ratio of iron ore powder to oxygen is 1:9, carbon monoxide is blown in, the volume ratio of carbon monoxide nozzle injection to oxygen injection is 100:9, and the temperature in the reduction furnace is controlled to 900～1500 ℃; the powder and carbon monoxide undergo a reduction reaction during the countercurrent movement in the furnace to obtain pre-reduced iron powder/iron droplets and pre-reduced tail gas with a metallization rate> 70%;

Step 3. Control the temperature in the electric melting furnace to 1600℃, and control the amount of flux added so that the binary basicity of the slag in the electric furnace is 1.0, the slag-forming agent is lime powder, the average particle size is 0.5mm, and the bottom of the electric melting furnace Inject carbon monoxide with a strength of 0.02m ³ /(tFe·min); stir the molten pool and complete the final reduction of melting at the same time. The molten steel and slag obtained by the final reduction are discharged from the tapping port and the slag tapping port respectively; the prepared molten steel The molten steel with a mass fraction of C of 0.01% to 0.40% and a temperature of 1600°C is used in the subsequent refining process to produce ultra-pure steel;

The above technical solutions illustrate the technical ideas of the present invention, and cannot be used to limit the scope of protection of the present invention. Any changes and modifications made to the above technical solutions based on the technical essence of the present invention without departing from the technical solutions of the present invention belong to The protection scope of the technical solution of the present invention.

Claims

A cyclone flash reduction direct steelmaking system, characterized in that, the system includes:

Carbon monoxide preparation device, cyclone flash reduction furnace, electric melting furnace and tail gas post-treatment equipment, said tail gas post-treatment equipment including preheating/pre-reduction device, tail gas dust removal and purification device, heat exchanger and tail gas separation device;

The carbon monoxide preparation device includes a carbon dioxide reduction reactor, a carbon monoxide storage tank and an oxygen storage tank, and the carbon dioxide reduction reactor is connected to the carbon monoxide storage tank and the oxygen storage tank through a pipeline;

The cyclone flash reduction furnace is provided with a feed inlet, a carbon monoxide nozzle, and a tail gas outlet, the tail gas outlet is arranged on the top of the furnace body, the feed inlet is arranged on the upper part of the furnace wall, and the carbon monoxide nozzle is arranged below the feed inlet On the furnace wall of, the carbon monoxide nozzle is connected to the carbon monoxide storage tank through a pipe, and the bottom of the cyclone flash reduction furnace is connected to the electric melting furnace;

The electric melting furnace is provided with an electrode, a steel tapping port, a slag tapping port and a bottom blowing element, and the bottom blowing element is connected to a carbon monoxide storage tank through a pipeline;

The preheating/pre-reduction device is provided with an air inlet, an air outlet, a material inlet, and a material outlet. The air inlet is connected to the tail gas outlet of the cyclone flash reduction furnace, and the air outlet is connected to a dust removal and purification device. The feed port is used to add iron ore powder and flux powder, and the feed port is connected to the feed port of the cyclone flash reduction furnace through a feed pipe;

The dust removal and purification device has a tail gas inlet, a tail gas outlet, and a dust removal discharge port, the tail gas inlet is connected to a preheating/prereduction device, the tail gas outlet is connected to a heat exchanger, and the dust removal ash discharge port is connected to a feed pipe ；

The heat exchanger has a first air inlet, a first air outlet, a second air inlet, and a second air outlet. The first air inlet is connected to the exhaust outlet of the dust removal and purification device, and the first air outlet is connected to The tail gas separation device is connected, the second air inlet is connected with the oxygen storage tank pipeline, and the second air outlet is connected with the feed pipeline;

The inlet end of the tail gas separation device is connected to a heat exchanger, and the outlet end is respectively connected to a carbon dioxide reduction reactor and a carbon monoxide storage tank through a pipeline;

The pipeline connecting the oxygen storage tank and the heat exchanger is provided with an oxygen flow regulating valve, the carbon monoxide storage tank is connected to the carbon monoxide nozzle, and the carbon monoxide storage tank is connected to the bottom blowing element of the electric melting furnace. All are equipped with carbon monoxide flow regulating valve.
The cyclone flash reduction direct steelmaking system according to claim 1, wherein the feed inlet of the cyclone flash reduction furnace is arranged along the tangential direction of the furnace body.
The cyclone flash reduction direct steelmaking system according to claim 1, wherein at least one bottom blowing element can be any one of a nozzle or a breathable brick.
A cyclone flash reduction direct steelmaking process based on the system of claim 1, wherein the process includes the following steps:

Step 1. Feed carbon dioxide into the carbon dioxide reduction reactor and perform electrochemical reduction to obtain pure carbon monoxide and oxygen. The purity of carbon monoxide is greater than 99%, and the purity of oxygen is greater than 99%. The carbon monoxide is transported to the carbon monoxide storage tank through the pipeline, and the oxygen is transported to the oxygen through the pipeline. Storage tank;

Step 2. The oxygen in the oxygen storage tank enters the heat exchanger to obtain the preheated oxygen; the iron ore powder and the flux powder enter the preheating/prereduction device to obtain the preheating/prereduction powder; the powder and the preheating oxygen are together Inject into the cyclone flash reduction furnace, and at the same time the carbon monoxide nozzle injects carbon monoxide to control the temperature in the furnace to 900～1500℃; the powder and carbon monoxide undergo a reduction reaction during the countercurrent movement in the cyclone furnace, and the metallization rate is more than 70%. Pre-reduced iron powder/iron droplets and pre-reduced tail gas;

Step 3. The pre-reduced iron powder/iron droplets formed in the cyclone flash reduction furnace directly fall into the electric melting furnace connected to the lower part due to gravity during the rotating movement along the furnace wall, and the electric heating melting furnace is controlled by the electrode heating The temperature is 1600～1750℃, the pre-reduced iron powder/iron droplets are electrothermally fused; at the same time, carbon monoxide is blown at the bottom, the molten pool is stirred and the melting is finalized, and the carbon monoxide blowing intensity is 0.01～0.2m 3 /(tFe·min) ; Carry out the continuous steelmaking process to obtain molten steel, slag and smelting tail gas. The molten slag and molten steel are discharged continuously or intermittently from the slag tap and the steel tap;

Step 4. The reduction tail gas produced in the cyclone flash reduction furnace and the smelting tail gas in the electric furnace are discharged from the tail gas outlet and enter the tail gas post-processing equipment; first, the high-temperature dust-containing tail gas is passed through the preheating/prereduction device, and the waste heat is used for preheating/prereducing Iron ore powder and flux powder, the cooled tail gas is sent to the dust removal purification device, after purification and dust removal, purified tail gas and dust removal ash are obtained, and the dust removal ash is returned to the cyclone flash reduction furnace, and the purified tail gas enters the heat exchanger for waste heat utilization and preheating The oxygen enters the tail gas separation device after cooling down to separate carbon monoxide and carbon dioxide. The carbon monoxide is transported to the carbon monoxide storage tank through the pipeline, and returned to the cyclone flash reduction furnace and the electric melting furnace as the reducing gas for recycling, and the carbon dioxide is transported to the carbon dioxide through the pipeline Reduce the reactor and recycle it.
The cyclone flash reduction direct steelmaking process according to claim 4, wherein the flux powder in step 2 is one or more of the steelmaking slagging agent lime, fluorite, and dolomite, The total iron TFe content of iron ore powder is ≥50wt%; the average particle size of iron ore powder and flux powder are both ≤2mm.
The cyclone flash reduction direct steelmaking process according to claim 5, wherein the mass ratio of iron ore powder to oxygen entering the cyclone flash reduction furnace in step 2 is 1:(1-9).
A cyclone flash reduction direct steelmaking process according to claim 4, wherein the process further comprises controlling the amount of flux added in step 2 so that the binary basicity of the slag in the electric melting furnace is 1.0～3.0.
A cyclone flash reduction direct steelmaking process according to claim 4, wherein the volume ratio of oxygen blown from the feed port to carbon monoxide blown from the carbon monoxide nozzle in step 2 is (1-9): 100.
The direct steelmaking process with cyclone flash reduction according to claim 4, wherein the heat in the electric melting furnace is provided by electric energy, and the source of heat in the cyclone flash reduction furnace is: The carbon monoxide combustion releases heat and the lower part is heated by an electric melting furnace.
The cyclone flash reduction direct steelmaking process according to claim 4, wherein the carbon dioxide in the carbon dioxide reduction reactor comes from an internal circulation, and the loss part is supplied from the outside.