CN110423854B - A kind of electric energy full hydrogen flash reduction direct steelmaking system and process - Google Patents

Abstract

An electric power full hydrogen flash reduction direct steelmaking system and process, the system comprises an electrolysis water hydrogen production device, a cyclone flash reduction furnace, an electric heating melting furnace, and a tail gas post-treatment equipment, and the process is: water electrolysis to prepare Reducing gas hydrogen and oxygen, oxygen and steelmaking powder are injected into the cyclone flash reduction furnace, and at the same time, hydrogen is injected into the lower part, and the gas-solid two-phase reduction reaction occurs at 500-1500 ℃ during the countercurrent movement in the cyclone furnace, and the metallization is obtained. Pre-reduced iron powder/iron droplets with a rate of >80%, enter the electric heating melting furnace for melting, bottom blowing hydrogen for stirring and melting for final reduction, continuous steelmaking, reduction and smelting tail gas preheating/pre-reduction powder and dust removal and purification, The purified tail gas preheats oxygen and condenses and separates, the hydrogen is returned to the cyclone flash reduction furnace, and the condensed water is returned to the electrolyzed water to produce hydrogen; this process completely utilizes electric energy for smelting, does not rely on fossil fuels, and completely uses hydrogen as a reducing agent, and the process does not emit pollutants , to achieve high efficiency, recycling of raw materials, and clean smelting.

Description

A kind of electric energy full hydrogen flash reduction direct steelmaking system and process

technical field

The invention relates to the technical field of metallurgy, in particular to a direct steelmaking system and a process for electric energy full hydrogen flash reduction.

Background technique

Sintering → blast furnace → converter is the main process of crude steel production at present. This process integrates four process links: sintering (or pelletizing), coking, blast furnace ironmaking and converter steelmaking. It has a long production process, high energy consumption, and strong dependence on fossils. Fuel resources and serious environmental pollution. With the current global environmental pollution and resource and energy shortage problems intensifying, 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 iron and steel industry.

Aiming at the problems of high pollution and high energy consumption in the traditional blast furnace ironmaking process, smelting reduction ironmaking technology has developed in recent years because it can reduce the dependence on high pollution and high energy consumption processes such as agglomeration, sintering, and coking. Important technological approaches for waste disposal and cleaner production, such as COREX, FINEX and HIsarna processes. In the COREX method, the upper pre-reduction shaft furnace is used to pre-reduce iron ore to obtain metallized pellets (DRI) with a metallization rate of 70% to 90%, and then the DRI is sent to the lower melter-gasifier for final reduction. The production process of this process still needs to rely on lump ore, pellet ore, sinter and some coke to maintain the furnace condition. The FINEX process uses fine ore as raw material, and uses 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 gasifier performs melting and final reduction. The HIsarna process takes powder ore as the main raw material, and uses a cyclone melting furnace to smelt the powder ore at a flash speed. It is reduced and melted in the smelting reduction furnace, and then flows along the furnace wall and drips into the smelting reduction furnace for final reduction.

Patent CN101117650A proposes a method for rapidly pre-reducing fine iron ore powder by smelting reduction, pre-reducing micron-level iron ore powder in a conveying 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 melter-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. Patents CN101906501A, CN101260448A, and CN108374067A propose a direct steelmaking process with fine ore and coal oxygen. After pre-reduction, iron ore powder is injected into a steelmaking furnace with coal powder and oxygen for steelmaking.

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

In 2011, the German federal government adopted the sixth energy research program - "Research for an environmentally friendly, reliable and cheap energy supply", which is perfectly suited to the problem of energy consumption in metallurgical processes. In the research of emerging energy, electric energy is placed in the first place. The wide application of electrical energy can easily find a substitute for carbon as a reducing agent in ironmaking, namely hydrogen. Hydrogen can be produced by electrolysis of water, and the product after iron oxide reduction is water, which can be recycled. At present, China National Nuclear Corporation, Tsinghua University, Baosteel Group and other relevant units have jointly carried out cooperation in the combination of nuclear hydrogen production and hydrogen metallurgy, and the proposal for "supporting nuclear hydrogen production and green metallurgy to be included in major national science and technology projects" has been submitted. . Therefore, it can be foreseen that in the future development, electric hydrogen metallurgy technology is an important technical way to achieve cleaner production in the iron and steel industry, and it will undoubtedly be a powerful impetus for the reform of metallurgical technology.

SUMMARY OF THE INVENTION

The technical task of the present invention is to provide an electric power full hydrogen flash reduction direct steelmaking system and process aiming at the above deficiencies of the prior art.

One aspect of the present invention provides an electric power full hydrogen flash reduction direct steelmaking system, the system comprising: an electrolysis water hydrogen production device, a cyclone flash reduction furnace, an electrothermal melting furnace, and a tail gas post-treatment device. The equipment includes a preheating/prereduction device, a dedusting and purification device and a heat exchanger connected by pipelines in sequence;

The electrolysis water hydrogen production device comprises an electrolysis water hydrogen production reactor, a hydrogen storage tank and an oxygen storage tank, and the electrolysis water hydrogen production reactor is connected with the hydrogen storage tank and the oxygen storage tank through a pipeline;

The top of the cyclone flash reduction furnace is provided with a tail gas outlet, the upper part of the furnace body is provided with a feed port, and a hydrogen nozzle is provided below the feed port, and the hydrogen nozzle is connected with the hydrogen storage tank through a pipeline. The bottom of the furnace is communicated with the electric heating sub-furnace;

The electrothermal melting furnace is provided with an electrode, a steel tap, a slag tap and a bottom blowing element, and the bottom blowing element is connected to the hydrogen storage tank through a pipeline;

The preheating/pre-reduction device has 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 port is used for adding iron ore powder and flux powder, and the discharge port is connected with the feeding port of the cyclone flash reduction furnace through the feeding pipeline;

The dust removal and purification device has a tail gas inlet, a tail gas outlet and a dust removal outlet, the tail gas inlet is connected to the preheating/pre-reduction device, the tail gas outlet is connected to a heat exchanger, and the dust removal and dust outlet is communicated with the feed pipeline ;

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 gas outlet of the dust removal and purification device, and the first air outlet is connected to the exhaust gas outlet of the dust removal and purification device. The hydrogen storage tank is connected with the pipeline, the second air inlet is connected with the oxygen storage tank pipeline, and the second air outlet is connected with the feed pipeline;

An oxygen flow regulating valve is arranged on the pipeline connecting the oxygen storage tank and the heat exchanger, on the pipeline connecting the hydrogen storage tank and the hydrogen nozzle, and on the pipeline connecting the hydrogen storage tank and the bottom blowing element of the electrothermal melting furnace All are equipped with hydrogen flow regulating valve.

Further, a condensed water outlet is also provided at the bottom of the heat exchanger, and the condensed water outlet is connected to the water inlet of the electrolysis water hydrogen production reactor.

Further, the feeding port of the cyclone flash reduction furnace is arranged along the tangential direction of the furnace body.

Further, the preheating/pre-reduction device is a single or multiple fluidized bed reactors in series, and the feeding port of the preheating/pre-reduction device is communicated with the iron ore powder feed hopper and the flux powder feed hopper .

Further, at least one of the bottom blowing elements may be any one of a nozzle or a ventilation brick.

Another aspect of the present invention provides an electric energy full hydrogen flash reduction direct steelmaking process based on the above system, and the process comprises the following steps:

Step 1. Add liquid water to the water electrolysis hydrogen production device, and perform water electrolysis to obtain pure hydrogen and oxygen. The purity of the obtained hydrogen is > 99%, and the purity of oxygen is > 99%. The hydrogen is transported to the hydrogen storage tank through the pipeline, and the oxygen is passed through the pipeline. delivered to the oxygen storage tank;

Step 2. The oxygen in the oxygen storage tank enters the heat exchanger to obtain preheated oxygen; the iron ore powder and the flux powder enter the preheating/prereduction device to obtain the preheated/prereduced powder; the powder and the preheated oxygen together It is sprayed into the cyclone flash reduction furnace, and at the same time hydrogen is injected from the hydrogen nozzle and the bottom ^of the electrothermal melting furnace. The inner temperature is 500～1500℃; the reduction reaction occurs between the powder and hydrogen during the countercurrent movement in the furnace, and the pre-reduced iron powder/drop and pre-reduction tail gas with metallization rate >80% are obtained;

Step 3. The pre-reduced iron powder/iron droplets formed in the cyclone flash reduction furnace fall directly into the electrothermal melting furnace connected to the lower part thereof due to the action of gravity during the rotary motion along the furnace wall, and the temperature in the electrothermal melting furnace is controlled to be 1550~ 1700 ℃, electrothermal melting of pre-reduced iron powder; under the action of blowing hydrogen at the bottom of the electrothermal melting furnace, molten pool stirring and melting final reduction are carried out; continuous steelmaking process is carried out to obtain molten steel, slag and melting tail gas, molten slag and molten steel are discharged continuously or intermittently from the slag outlet and the steel outlet of the electric heating sub-furnace respectively;

Step 4. The pre-reduction tail gas generated in the cyclone flash reduction furnace and the smelting tail gas in the electrothermal melting furnace are discharged from the tail gas outlet of the cyclone flash reduction furnace. The iron ore powder and flux powder are pre-reduced, and the cooled tail gas is sent to the dust removal and purification device. After purification and dust removal, purified tail gas and dust removal ash are obtained. 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. After preheating the oxygen, cooling and condensing, the hydrogen and condensed water are separated, and the hydrogen is transported to the hydrogen storage tank through the pipeline, and returned to the cyclone flash reduction furnace and the electrothermal melting furnace as reducing gas for recycling, and the condensed water is transported through the pipeline. Go to the electrolysis water reactor for electrolysis and recycle.

Further, the flux powder is one or more of lime, fluorite, and dolomite, the slag-making materials for steelmaking, and the total iron TFe content of the iron ore powder is 30-70 wt%; the particle size of the iron ore powder and the flux powder is All ≤1000μm.

Further, the iron ore powder and oxygen enter into the cyclone flash reduction furnace at a mass ratio of 1:(1-10).

Further, the addition amount of the flux powder is controlled according to the standard that the binary basicity of the molten slag in the electrothermal melting furnace is 0.8-3.0.

Further, the volume ratio of the amount of oxygen blown into the feed port of the cyclone flash reduction furnace and the amount of hydrogen blown into the hydrogen nozzle is (1-10):100.

The invention proposes a direct steel-making device and process for electric full hydrogen flash reduction. The process uses an electrolytic water reactor, a cyclone flash reduction furnace, and an electrothermal melting furnace as the main equipment, and uses the electrolytic water reactor to produce reducing gas hydrogen gas. At the same time, additional gas oxygen is obtained; oxygen and iron-containing powder are injected into the cyclone flash reduction furnace from the upper feeding port of the cyclone furnace along the tangential direction of the furnace body, and the reducing gas hydrogen is blown in from the bottom of the feeding port, and part of the hydrogen is burned. The heat release provides part of the heat in the furnace, and the gas-solid two-phase reduction reaction occurs during the countercurrent motion in the cyclone flash reduction furnace, and the pre-reduced iron powder/iron droplets with metallization rate > 80% are obtained; pre-reduced iron powder/iron The droplets fall into the electrothermal melting furnace connected to the bottom of the cyclone flash reduction furnace, and conduct electrothermal melting. At the same time, hydrogen is injected from the bottom of the electrothermal melting furnace to stir the molten pool and reduce the final smelting, so as to realize continuous steelmaking, and separate steel and slag. It is discharged from the steel tap and slag tap; high temperature reduction and smelting tail gas preheat/pre-reduce iron ore powder and flux powder, and after dust removal and purification, the dust dust is returned to the cyclone flash reduction furnace, and the purified tail gas enters the heat exchanger for use The residual heat preheats the oxygen/hydrogen, and after cooling, the condensed water and hydrogen are separated, and the condensed water is returned to the electrolyzed water system, and the hydrogen is sent to the hydrogen storage tank to realize resource recycling. The new process uses all-electric smelting, which avoids the use of non-renewable energy sources such as fossil fuels. The reducing gas uses hydrogen completely and is recycled, and the process is pollution-free, realizing the efficient and recycling of raw materials and clean production of products.

Compared with existing methods, the present invention has the following beneficial effects:

(1) Compared with the traditional iron and steel smelting process, the present invention completely uses electric energy as the energy supply 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, biomass energy, etc. , which is conducive to alleviating the problem of energy shortage;

(2) The present invention completely adopts hydrogen as the reducing gas, and the thermal conductivity of hydrogen is far greater than that of carbon monoxide, so it can accelerate the gas-solid two-phase heat exchange, and the reducing power of hydrogen is stronger than that of carbon monoxide, which is conducive to obtaining high Reduced iron powder with metallization rate; the hydrogen reduction product is water vapor, no CO ₂ emission, the water vapor can be returned to the electrolysis water hydrogen production system for recycling, which not only reduces the environmental load, but also realizes clean production;

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

(4) the present invention adopts the cyclone flash reduction furnace to carry out the pre-reduction of the iron ore powder, and the iron ore powder makes a circular downward movement along the furnace wall in the cyclone flash reduction furnace, which can prolong the residence time of the powder in the furnace and The contact time with the reducing gas is beneficial to increase the reduction rate.

Description of drawings

Fig. 1 is the system structure schematic diagram of the present invention;

Reference numerals: 1- electrolyzed water hydrogen production reactor, 2- hydrogen storage tank, 3- oxygen storage tank, 4- iron ore powder feeding hopper, 5- flux powder feeding hopper, 6- cyclone flash reduction furnace, 7- Electrothermal melting furnace, 8- Oxygen flow control valve for cyclone flash reduction furnace, 9- Hydrogen flow control valve for cyclone flash reduction furnace, 10- Hydrogen flow control valve for electrothermal melting furnace, 11- Preheating/pre-reduction device , 12- dust removal and purification device, 13- heat exchanger, 14- feed pipeline;

Among them, the cyclone flash reduction furnace includes: 601 - feed inlet, 602 - hydrogen nozzle, 603 - tail gas outlet;

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

Wherein, the heat exchanger includes, 1301-first air inlet, 1302-first air outlet, 1303-second air inlet, 1304-second air outlet, and 1305-condensate water outlet;

A- iron ore powder, B- flux powder, C- liquid water, D- hydrogen, E- oxygen, F- slag, G- molten steel, H- tail gas, I- preheated/pre-reduced powder, J- cooling Dust-containing exhaust gas, K-dust dust;

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

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below 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 to limit the present invention.

As shown in FIG. 1, the present invention provides a direct steelmaking system with electric power full hydrogen flash reduction, the system includes: an electrolysis water hydrogen production device, a cyclone flash reduction furnace, an electric heating melting furnace, and a tail gas post-treatment equipment, all of which are The exhaust gas post-processing equipment includes a preheating/prereduction device, a dust removal and purification device and a heat exchanger connected by pipelines in sequence;

The electrolyzed water hydrogen production device comprises an electrolytic water hydrogen production reactor 1, a hydrogen storage tank 2 and an oxygen storage tank 3, and the electrolytic water hydrogen production reactor is connected with the hydrogen storage tank and the oxygen storage tank through a pipeline;

The top of the cyclone flash reduction furnace 6 is provided with a tail gas outlet 603, the upper part of the furnace body is provided with a feed port 601, the feed port is arranged along the tangential direction of the cyclone flash reduction furnace, and a hydrogen nozzle 602 is provided below the feed port , the hydrogen nozzle is connected with the hydrogen storage tank through a pipeline, a hydrogen flow regulating valve 9 is arranged on the connecting pipeline, and the bottom of the cyclone flash reduction furnace is communicated with the electrothermal melting furnace 7;

The electrothermal melting furnace is provided with an electrode 701, a steel tapping port 703, a slag tapping port 704 and a bottom blowing element 702. The steel 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 hydrogen storage tank through a pipeline, and a hydrogen flow regulating valve 10 is arranged on the connecting pipeline;

The preheating/prereduction device 11 adopts a single or multiple fluidized bed reactors in series, and has a gas inlet, a gas outlet, a material inlet, and a material outlet, and the gas inlet is connected to the tail gas outlet of the cyclone flash reduction furnace. , the air outlet is connected to the dust removal and purification device 12, the feed port is used to add iron ore powder and flux powder, and the feed port is communicated with the iron ore powder feed hopper 4 and the flux powder feed hopper 5. The discharge port is connected with the feed port of the cyclone flash reduction furnace through the feeding pipeline 14;

The dust removal and purification device has a tail gas inlet, a tail gas outlet and a dust removal outlet. The tail gas inlet is connected to the preheating/pre-reduction device, the tail gas outlet is connected to the heat exchanger 13, and the dust removal and dust outlet is connected to the feed pipeline. 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 gas outlet of the dust removal and purification device. An air outlet is connected to the pipeline of the hydrogen storage tank, the second air inlet is connected to the pipeline of the oxygen storage tank, the connecting pipeline is provided with an oxygen flow regulating valve 8, and the second air outlet is connected to the feed pipeline.

Wherein, at least one of the bottom blowing elements of the electrothermal melting furnace may be any one of a nozzle or a breathable brick.

As an improvement of the technical solution, a condensed water outlet 1305 is also provided at the bottom of the heat exchanger, and the condensed water outlet is connected with the water inlet of the electrolyzed water hydrogen production reactor.

The present invention provides a direct steel-making process based on the above-mentioned system with full hydrogen flash reduction of electric energy. The process flow is shown in Figure 2 and includes the following steps:

Step 1. Add liquid water to the water electrolysis hydrogen production device, and carry out water electrolysis to obtain pure hydrogen D and oxygen E. The purity of the obtained hydrogen is > 99%, and the purity of oxygen is > 99%. The hydrogen is transported to the hydrogen storage tank through the pipeline, and the oxygen Piped to the oxygen storage tank;

Step 2. The oxygen in the oxygen storage tank enters the heat exchanger, and is preheated by the high-temperature purified exhaust gas to obtain preheated oxygen; the iron ore powder A and the flux powder B enter the preheating/pre-reduction device from the feeding hopper, and are passed through the high-temperature exhaust gas. Preheating/prereduction to obtain preheated/prereduced powder and purified exhaust gas; the powder and preheated oxygen are sprayed into the cyclone flash reduction furnace along the tangential direction of the furnace body from the feeding port, and the hydrogen in the hydrogen storage tank is The hydrogen nozzle located below the feed port and the bottom of the electrothermal melting furnace are blown into the furnace. The hydrogen blowing intensity of the electrothermal melting furnace to the bottom of the molten pool is 0.01-0.5m ³ /(tFe·min), and the temperature in the furnace is controlled at 500-1500 ℃; the powder and hydrogen undergo a reduction reaction in the process of countercurrent movement in the furnace to obtain pre-reduced iron powder/droplets and pre-reduced tail gas with a metallization rate >80%; at the same time, part of the hydrogen and oxygen undergoes combustion reaction and exothermic heat, which is the furnace The internal reduction process provides part of the physical heat;

Step 3. The pre-reduced iron powder/iron droplets formed in the cyclone flash reduction furnace directly fall into the electrothermal melting furnace connected with the lower part of the cyclone flash speed reduction furnace due to the action of gravity during the rotational movement along the furnace wall, and the electrothermal melting furnace passes through the furnace. Electrode heating, the furnace temperature is controlled at 1550-1700 °C, and the pre-reduced iron powder is electrothermally smelted; under the action of blowing hydrogen at the bottom of the electrothermal smelting furnace, the molten pool is stirred and the final reduction of melting is performed; the continuous steelmaking process is carried out to obtain Molten steel G, slag F and smelting tail gas, slag and molten steel are discharged continuously or intermittently from the slag outlet and steel outlet of the electric heating sub-furnace respectively;

Step 4. The reduction tail gas generated in the cyclone flash reduction furnace and the smelting tail gas in the electrothermal melting furnace are discharged from the tail gas outlet located at the top of the cyclone flash reduction furnace. Heat/pre-reduce iron ore powder and flux powder to obtain pre-heated/pre-reduced powder I, and the dust-containing exhaust gas J after cooling is sent to the dedusting and purification device. Flash reduction furnace, purified exhaust gas enters the heat exchanger for waste heat utilization, preheats oxygen, and at the same time cools down and condenses, separates hydrogen and condensed water, and transports hydrogen to hydrogen storage tank through pipeline, and returns to cyclone furnace and cyclone as reducing gas. The electric furnace is recycled, and the condensed water is transported to the electrolysis water reactor through the pipeline for electrolysis and recycled.

Wherein, the flux powder is one of slag-forming materials lime, fluorite and dolomite, the total iron TFe content of the iron ore powder is 30-70wt%; the particle size of the iron ore powder and the flux powder is ≤1000μm.

Wherein, the iron ore powder and oxygen enter into the cyclone flash reduction furnace at a mass ratio of 1:(1-10).

Wherein, the addition amount of the flux is controlled with the standard that the binary basicity of the molten slag in the electric furnace is 0.8-3.0.

Wherein, the volume ratio of the amount of oxygen blown into the feed port of the cyclone flash reduction furnace and the amount of hydrogen blown into the hydrogen nozzle is (1-10):100.

Among them, in the direct steel-making process with full hydrogen flash reduction, the energy required for the entire system (including the water electrolysis device and the electrothermal melting furnace) comes from electric energy, and the electric energy generation method can be any non-fossil fuel power generation such as nuclear energy, solar energy, water power, etc. .

Among them, in the direct steel-making process with full hydrogen flash reduction, the electrolyzed water comes from the internal circulation, and the lost part is supplied from the outside.

Wherein, in the method for direct steelmaking by full hydrogen flash reduction, the temperature in the cyclone flash reduction furnace is controlled at 500-1500°C, and a part of the heat in the furnace comes from the combustion and exotherm of hydrogen in the furnace, and a part comes from the cyclone. The lower part of the flash reduction furnace is heated by an electrothermal melting furnace.

Wherein, in the method for direct steelmaking by full hydrogen flash reduction, the temperature of the electric heating melting furnace is controlled at 1550-1700°C, and the heat is provided by electric energy.

Example 1

A kind of electric energy full hydrogen flash reduction direct steelmaking process using the above system and process, the process parameters involved in each step are as follows:

Step 1. Add liquid water to the water electrolysis hydrogen production device, carry out water electrolysis to obtain pure hydrogen and oxygen, the obtained hydrogen purity>99%, oxygen purity>99%;

Step 2. Add the iron ore powder and the flux powder into the preheating/pre-reduction device, the total iron TFe content of the iron ore powder is 30wt%, and the particle size is less than or equal to 1000 μm to obtain the preheated/pre-reduced powder, iron ore powder and flux The powder is injected into the cyclone flash reduction furnace together with the preheated oxygen, wherein the mass ratio of iron ore powder and oxygen is 1:5, the hydrogen nozzle is blown into hydrogen, and the volume ratio of the hydrogen injection amount to the oxygen injection amount is 100:5 , control the temperature in the reduction furnace to be 500-1500 °C; the powder and hydrogen undergo a reduction reaction during the countercurrent movement in the cyclone flash reduction furnace, and obtain pre-reduced iron powder/iron droplets and pre-reduced tail gas with a metallization rate > 80% ;

Step 3. Control the temperature in the electrothermal melting furnace to be 1700°C, and control the amount of flux added so that the binary basicity of the slag in the electrothermal melting furnace is 0.8, the slag-forming agent is lime powder, and the particle size is less than or equal to 1000 μm; the bottom of the electrothermal melting furnace The hydrogen with an intensity of 0.05m ³ /(tFe·min) was injected, the molten pool was stirred, and the final reduction of melting was completed at the same time. The molten steel and slag obtained by the final reduction were discharged from the tapping port and the slag tapping port respectively; the prepared molten steel was The molten steel with a mass fraction of C of 0.01-0.40% and a temperature of 1700°C is used for the subsequent refining process to produce ultra-pure steel;

Step 4. Reduction and smelting tail gas preheating/pre-reduction powder and dedusting purification, purification tail gas preheating oxygen and condensation separation, hydrogen return to cyclone flash reduction furnace, condensed water return to electrolyzed water to produce hydrogen.

Example 2

A kind of electric energy full hydrogen flash reduction direct steelmaking process using the above system and process, the process parameters involved in each step are as follows:

Step 1. Add liquid water to the water electrolysis hydrogen production device, carry out water electrolysis to obtain pure hydrogen and oxygen, the obtained hydrogen purity>99%, oxygen purity>99%;

Step 2. Add the iron ore powder and the flux powder into the preheating/pre-reduction device, the iron ore powder has a total iron TFe content of 50wt%, the particle size is less than or equal to 1000 μm, and the iron ore powder and the flux powder are blown into the cyclone flash together with the preheated oxygen. A high-speed reduction furnace, in which the mass ratio of iron ore powder to oxygen is 1:7, the hydrogen nozzle is blown into hydrogen, the volume ratio of the hydrogen injection amount to the oxygen injection amount is 100:7, and the temperature in the reduction furnace is controlled to be 500-1500 ℃; the reduction reaction occurs between the powder and hydrogen during the countercurrent movement in the cyclone flash reduction furnace, and the pre-reduced iron powder/droplet and the pre-reduction tail gas with metallization rate > 80% are obtained;

Step 3. Control the temperature in the electrothermal melting furnace to be 1650°C, and control the amount of flux added so that the binary basicity of the slag in the electrothermal melting furnace is 2.0, the slag-forming agent is lime powder, and the particle size is less than or equal to 1000 μm; the bottom of the electrothermal melting furnace Hydrogen with an intensity of 0.1m ³ /(tFe·min) was injected, the molten pool was stirred, and the final reduction of melting was completed at the same time. The molten steel and slag obtained by the final reduction were discharged from the tapping port and the slag tapping port respectively; the prepared molten steel was The molten steel with a mass fraction of C of 0.01-0.40% and a temperature of 1650°C is used for the subsequent refining process to produce ultra-pure steel;

Step 4. Reduction and smelting tail gas preheating/pre-reduction powder and dedusting purification, purification tail gas preheating oxygen and condensation separation, hydrogen return to cyclone flash reduction furnace, condensed water return to electrolyzed water to produce hydrogen.

Example 3

A kind of electric energy full hydrogen flash reduction direct steelmaking process using the above system and process, the process parameters involved in each step are as follows:

Step 1. Add liquid water to the water electrolysis hydrogen production device, carry out water electrolysis to obtain pure hydrogen and oxygen, the obtained hydrogen purity>99%, oxygen purity>99%;

Step 2. Add the iron ore powder and the flux powder into the preheating/pre-reduction device. The iron ore powder has a total iron TFe content of 70wt%, and the particle size is less than or equal to 1000 μm. The iron ore powder and the flux powder are blown into the cyclone flash together with the preheated oxygen. A high-speed reduction furnace, in which the mass ratio of iron ore powder to oxygen is 1:10, the hydrogen nozzle is blown into hydrogen, the volume ratio of the hydrogen injection amount to the oxygen injection amount is 100:10, and the temperature in the reduction furnace is controlled to be 500-1500 ℃; the reduction reaction occurs between the powder and hydrogen during the countercurrent movement in the cyclone flash reduction furnace, and the pre-reduced iron powder/droplet and the pre-reduction tail gas with metallization rate > 80% are obtained;

Step 3. Control the temperature in the electrothermal melting furnace to be 1550°C, and control the amount of flux added to make the binary basicity of the slag in the electrothermal melting furnace be 3.0, the slag-forming agent is lime powder, and the particle size is ≤1000 μm; the electrothermal melting furnace The bottom is sprayed with hydrogen with a strength of 0.2m ³ /(tFe·min), the molten pool is stirred, and the final reduction of melting is completed at the same time. It is molten steel with a mass fraction of C of 0.01-0.40% and a temperature of 1550 ° C, which is used for the subsequent refining process to produce ultra-pure steel;

Step 4. Reduction and smelting tail gas preheating/pre-reduction powder and dedusting purification, purification tail gas preheating oxygen and condensation separation, hydrogen return to cyclone flash reduction furnace, condensed water return to electrolyzed water to produce hydrogen.

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

Claims (8)

1. An electric energy full hydrogen flash reduction direct steelmaking system, the system comprising: the system comprises an electrolytic water hydrogen production device, a cyclone flash reduction furnace, an electric hot melting furnace and tail gas post-treatment equipment, wherein the tail gas post-treatment equipment comprises a preheating/pre-reduction device, a dust removal purification device and a heat exchanger which are sequentially connected through pipelines;

the water electrolysis hydrogen production device comprises a water electrolysis hydrogen production reactor, a hydrogen storage tank and an oxygen storage tank, wherein the water electrolysis hydrogen production reactor is connected with the hydrogen storage tank and the oxygen storage tank through pipelines;

the top of the cyclone flash reduction furnace is provided with a tail gas outlet, the upper part of the furnace body is provided with a feed inlet, the feed inlet of the cyclone flash reduction furnace is arranged along the tangential direction of the furnace body, a hydrogen nozzle is arranged below the feed inlet and is connected with a hydrogen storage tank through a pipeline, the whole bottom of the cyclone flash reduction furnace is communicated with the electric hot melting furnace, and the cyclone flash reduction furnace is communicated with the inner cavity of the electric hot melting furnace to form an integrated structure;

the electric melting furnace is provided with an electrode, a steel tapping hole, a slag hole and a bottom blowing element, and the bottom blowing element is connected with a hydrogen storage tank through a pipeline;

the preheating/pre-reducing device is provided with an air inlet, an air outlet, a feeding port and a discharging port, the air inlet is connected with a tail gas outlet of the cyclone flash reducing furnace, the air outlet is connected with the dust removal and purification device, the feeding port is used for adding iron ore powder and flux powder, and the discharging port is connected with a feeding port of the cyclone flash reducing furnace through a feeding pipeline;

the dust removal purification device is provided with a tail gas inlet, a tail gas outlet and a dust removal ash discharge hole, the tail gas inlet is connected with the preheating/pre-reduction device, the tail gas outlet is connected with the heat exchanger, and the dust removal ash discharge hole is communicated with a cyclone flash reduction furnace feed pipeline;

the heat exchanger is provided with a first air inlet, a first air outlet, a second air inlet and a second air outlet, the first air inlet is connected with a tail gas outlet of the dust removal and purification device, the first air outlet is connected with a hydrogen storage tank pipeline, the second air inlet is connected with an oxygen storage tank pipeline, and the second air outlet is communicated with a feeding pipeline; the bottom of the heat exchanger is also provided with a condensed water outlet which is connected with a water inlet of the electrolyzed water hydrogen production reactor;

and an oxygen flow regulating valve is arranged on a pipeline connecting the oxygen storage tank and the heat exchanger, and hydrogen flow regulating valves are arranged on a pipeline connecting the hydrogen storage tank and the hydrogen nozzle and a pipeline connecting the hydrogen storage tank and the bottom blowing element of the electric melting furnace.

2. An electric energy all-hydrogen flash reduction direct steelmaking process based on the system of claim 1, wherein the process comprises the steps of:

step 1, adding liquid water into an electrolytic water hydrogen production reactor, and electrolyzing the water to obtain pure hydrogen and oxygen, wherein the purity of the prepared hydrogen is more than 99 percent, the purity of the prepared oxygen is more than 99 percent, the hydrogen is conveyed to a hydrogen storage tank through a pipeline, and the oxygen is conveyed to an oxygen storage tank through a pipeline;

step 2, oxygen in the oxygen storage tank enters a heat exchanger to obtain preheated oxygen; feeding iron ore powder and flux powder into a preheating/pre-reducing device to obtain preheating/pre-reducing powder; the powder and preheated oxygen are sprayed into the cyclone flash reduction furnace together, meanwhile, hydrogen is blown in from the hydrogen nozzle and the bottom of the electric melting furnace, and the intensity of hydrogen blown to the bottom of the molten pool by the electric melting furnace is 0.01-0.5 m³(tFe. min), controlling the temperature in the reduction furnace to be 500-1500 ℃; the powder and hydrogen are subjected to reduction reaction in the process of countercurrent movement in the furnace to obtain metallization rate>80% of pre-reduced iron powder/iron drops and pre-reduced tail gas;

step 3, directly dropping the pre-reduced iron powder/iron drops formed in the cyclone flash reduction furnace into an electric melting furnace communicated with the lower part of the cyclone flash reduction furnace due to the action of gravity in the process of rotating the furnace wall, controlling the temperature in the electric melting furnace to be 1550-1700 ℃, and carrying out electric melting separation on the pre-reduced iron powder; under the action of bottom blowing hydrogen of the electrothermal melting furnace, carrying out molten pool stirring and final melting reduction; carrying out a continuous steelmaking process to obtain molten steel, slag and smelting tail gas, wherein the molten slag and the molten steel are continuously or intermittently discharged from a slag outlet and a steel outlet of the electrothermal smelting furnace respectively;

and 4, discharging pre-reduced tail gas generated in the cyclone flash reduction furnace and smelting tail gas in the electric heating smelting furnace from a tail gas outlet of the cyclone flash reduction furnace, firstly, passing the high-temperature tail gas through a preheating/pre-reduction device, preheating/pre-reducing iron ore powder and flux powder by utilizing waste heat, feeding the cooled tail gas into a dust removal purification device, purifying and removing dust to obtain purified tail gas and dust, returning the dust to the cyclone flash reduction furnace, feeding the purified tail gas into a heat exchanger, utilizing the waste heat, preheating oxygen, simultaneously cooling and condensing to separate hydrogen and condensed water, conveying the hydrogen to a hydrogen storage tank through a pipeline to be used as reducing gas to return to the cyclone flash reduction furnace and the electric heating smelting furnace for recycling, and conveying the condensed water to an electrolytic water reactor through a pipeline for electrolysis and recycling.

3. The electric energy total hydrogen flash reduction direct steelmaking process according to claim 2, wherein in step 2 the flux powder is one or more of steelmaking slag making materials lime, fluorite and dolomite, and the total iron TFe content of the iron ore powder is 30-70 wt%; the granularity of the iron ore powder and the flux powder is less than or equal to 1000 mu m.

4. The electric energy full hydrogen flash reduction direct steelmaking process according to claim 2, wherein the iron ore powder and oxygen enter the cyclone flash reduction furnace in a mass ratio of 1: 1-10.

5. The electric energy full hydrogen flash reduction direct steelmaking process according to claim 2, wherein the addition amount of the flux powder is controlled according to the standard that the binary basicity of the slag in the electric heating melting furnace is 0.8-3.0.

6. The electric energy full hydrogen flash reduction direct steelmaking process according to claim 2, wherein the volume ratio of the amount of oxygen blown into the feeding port of the cyclone flash reduction furnace to the amount of hydrogen blown into the hydrogen nozzle is (1-10): 100.

7. the electric energy full hydrogen flash reduction direct steelmaking process according to claim 2, wherein the heat in the electrothermal melting furnace is provided by electric energy, and the heat sources in the cyclone flash reduction furnace are as follows: hydrogen in the furnace is combusted to release heat and the lower part of the electric melting furnace is heated.

8. The electric energy all-hydrogen flash reduction direct steelmaking process of claim 2, wherein the part of the electrolyzed water used in the electrolyzed water hydrogen making reactor comes from internal circulation, and the lost part is supplied from the outside.

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