CN116790836A - A method for hydrogen-based direct reduced iron production and long-distance hot charging electric furnace - Google Patents

Abstract

The invention relates to a method for producing hydrogen-based direct reduced iron and a long-distance hot charging electric furnace, and belongs to the technical field of hydrogen-based direct reduced iron in the metallurgical industry. The technical solution is: Step 1: Load the iron ore pellets into the shaft furnace reactor (01) from the top of the shaft furnace reactor (01), and at the same time inject the purified hydrogen-based reducing gas from the lower part of the shaft furnace reactor (01) From the shaft furnace reactor (01), the hydrogen-based reducing gas and iron ore pellets flow counter-currently in the shaft furnace reactor (01) and react to form direct reduced iron, which is alternately put into the pressurized exhaust through the discharge buffer tank (08). In the silo (09); Step 2: Discharge the direct reduced iron in the pressurized discharge bin (09) into the direct reduced iron can (19) in an orderly manner; Step 3: Pass the direct reduced iron can (19) through the train Transported to the electric furnace workshop for use in electric furnace steelmaking. The beneficial effects of the invention are: optimizing the hydrogen reduction shaft furnace process, saving energy and reducing consumption, and realizing the long-distance hot charging electric furnace of hydrogen-based direct reduced iron.

Description

A method for hydrogen-based direct reduced iron production and long-distance hot charging electric furnace

Technical field

The invention relates to a method for hydrogen-based direct reduced iron production and long-distance hot charging electric furnace, and belongs to the technical field of hydrogen-based direct reduced iron production and hot charging electric furnace in the metallurgical industry.

Background technique

The metallic iron obtained by reducing ore in solid state using H ₂ etc. as energy and reducing agent is called direct reduced iron (DRI). It is a very ideal smelting raw material and can replace part or even all scrap steel in electric furnace steelmaking. For a long time, due to the influence of electric furnace steelmaking costs, resources and other factors, the power to drive the promotion of hydrogen reduction shaft furnace technology has been limited. The research on hydrogen reduction shaft furnace technology has not received enough attention. However, with the gradual increase of environmental protection pressure and human With the continuous development of clean energy sources such as hydrogen energy, it will not be far away to apply the hydrogen reduction shaft furnace process to a wider range in the future to meet the growing commercial demand for DRI.

Carbon emissions will bring pressure to human survival, and a consensus has gradually been reached around the world. The steel industry has always been a major emitter. According to domestic and international situations, various steel companies have successively introduced emission reduction measures. The direct reduction + electric furnace short process process is used to replace the previous blast furnace + converter long process process, which has fully demonstrated its advantages in reducing carbon emissions. Among them, the preparation of direct reduced iron in gas-based shaft furnaces has become the preferred direct reduction smelting process. This process currently still has energy There are issues such as waste and environmental protection. In addition, the method of loading direct reduced iron into the electric furnace in hot state is the pneumatic conveying system developed by Tenon Hill Company, which uses nitrogen as the conveying medium and the conveying method is pipeline conveying; the other is Meade Developed by Rex, it is transported using plate and belt conveyors or heat-resistant containers. The pneumatic conveying developed by Hill Company cannot meet the requirements for long-distance transportation; although the process developed by Midrex can meet the transportation distance requirements of 100 to 200m, the plate and belt conveyor method has a large heat loss during transportation. ; When transported in heat-resistant containers, due to the low carbon content of direct reduced iron, there is a problem of easy re-oxidation.

Contents of the invention

The purpose of the present invention is to provide a method for hydrogen-based direct reduced iron production and long-distance hot charging electric furnace, optimize the hydrogen reduction shaft furnace process, save energy and reduce consumption, and realize hydrogen-based direct reduced iron long-distance hot charging electric furnace to solve the background technology problems existing in.

The technical solution of the present invention is:

A method for hydrogen-based direct reduced iron production and long-distance hot charging electric furnace, including the following steps:

Step 1: Load the iron ore pellets into the shaft furnace reactor from the top of the shaft furnace reactor, and at the same time, pressurize the purified hydrogen-based reducing gas through the hydrogen-based reducing gas pressurizing system and inject it from the lower part of the shaft furnace reactor into the shaft furnace reactor. Furnace reactor, hydrogen-based reducing gas and iron ore pellets flow counter-currently and react in the shaft furnace reactor;

The waste gas after the reaction between the hydrogen-based reducing gas and the pellets is discharged from the top of the shaft furnace reactor, and passes through the waste heat recovery system, cooling and dust removal system, pressurization system, _CO2 removal system and heating furnace in sequence, and then passes through the shaft furnace reactor Inject in the middle to form recycling;

The direct reduced iron formed after the reaction between hydrogen-based reducing gas and pellets is discharged from the bottom of the shaft furnace reactor, enters the discharge buffer tank, and is alternately placed into the pressurized discharge bin through the discharge buffer tank;

Step 2: Discharge the direct reduced iron in the pressurized discharge bin into the direct reduced iron tank in an orderly manner;

Step 3: Transport the direct reduced iron cans containing direct reduced iron to the electric furnace workshop by train to be used in the electric furnace for steelmaking.

In the third step, when the train is transporting the direct reduced iron can, nitrogen is filled into the direct reduced iron can to inert the atmosphere in the direct reduced iron can.

The direct reduction iron tank is equipped with a sliding cover, and nitrogen is filled into the direct reduction iron tank through the nitrogen storage tank, the nitrogen pressurization valve and the sliding cover.

In the second step, the temperature of the direct reduced iron discharged from the pressurized discharge bin is 500-600°C.

In the first step, the purified hydrogen-based reducing gas is pressurized through the hydrogen-based reducing gas pressurizing system and then part of it is injected from the lower part of the shaft furnace reactor into the shaft furnace reactor, and the other part is used as fuel gas for the heating furnace.

The beneficial effects of the invention are: optimizing the hydrogen reduction shaft furnace process, and realizing the long-distance hot charging electric furnace of hydrogen-based direct reduced iron, which not only saves energy and reduces consumption, but also ensures that the direct reduced iron will not be re-oxidized, and improves the use of direct reduced iron. efficiency, reduce the cost of electric furnace steelmaking, and help promote the rapid development of direct reduction and electric furnace processes.

Description of the drawings

Figure 1 is a schematic diagram of the invention;

In the picture: shaft furnace reactor 01, waste heat recovery system 02, cooling and dust removal system 03, pressurization system 04, CO2 removal system 05, heating furnace 06, hydrogen-based reducing gas pressurization system 07, discharge buffer tank 08, adding Pressure discharge bin 09, material flow cut-off valve 10, normal pressure charging bin 11, pressurized charging bin 12, nitrogen pressure reducing valve 13, nitrogen pressurizing valve 14, sliding cover 15, hanging ear 16, tanker 17, nitrogen 18 storage tanks, 19 direct reduction iron tanks, 20 overhead cranes, and 21 electric steelmaking furnaces.

Implementation

The present invention will be further described below through examples in conjunction with the accompanying drawings.

Referring to Figure 1, a method for hydrogen-based direct reduced iron production and remote hot charging electric furnace includes the following steps:

Step 1: Load the iron ore pellets into the shaft furnace reactor 01 from the top of the shaft furnace reactor 01, and at the same time, pressurize the purified hydrogen-based reducing gas through the hydrogen-based reducing gas pressurizing system 07 and then discharge it from the shaft furnace reactor 01 The lower part is injected from the shaft furnace reactor 01, and the hydrogen-based reducing gas and iron ore pellets flow countercurrently and react in the shaft furnace reactor 01;

The waste gas after the reaction between the hydrogen-based reducing gas and the pellets is discharged from the top of the shaft furnace reactor 01, and passes through the waste heat recovery system 02, the cooling and dust removal system 03, the pressurizing system 04, the CO ₂ removal system 05 and the heating furnace 06 in sequence. Then inject it from the middle of shaft furnace reactor 01 to form recycling;

The direct reduced iron formed after the reaction between the hydrogen-based reducing gas and the pellets is discharged from the bottom of the shaft furnace reactor 01, enters the discharge buffer tank 08, and is alternately placed into the pressurized discharge bin 09 through the discharge buffer tank 08;

Step 2: Orderly discharge the direct reduced iron in the pressurized discharge bin 09 to the direct reduced iron tank 19;

Step 3: Transport the direct reduced iron can 19 containing direct reduced iron to the electric furnace workshop by train to be used in the electric furnace for steelmaking.

In this embodiment, referring to Figure 1, the process flow of hydrogen-based direct reduced iron production and remote hot charging electric furnace is as follows:

High-quality pelletized iron ore is first loaded into the atmospheric pressure silo 11, which acts as a buffer to ensure continuous charging of the shaft furnace;

The normal pressure silo 1 discharges materials to the pressurized silo 12. The function of the pressurized silo 12 is to raise the pressure of high-quality pellets 20 to 25Kpa higher than the shaft furnace reactor to facilitate loading into the shaft furnace reactor;

The high-quality pellets loaded into the shaft furnace reactor 01 are in counter-current contact with the reducing gas (gas mixed with the circulating gas and the hydrogen-based reducing gas injected from the cone of the shaft furnace reactor 01); the pellets lose their content of oxygen to form direct reduced iron with high metallization rate; the direct reduced iron is discharged from the lower part of the shaft furnace reactor 01 to the discharge buffer tank 08. The discharge buffer tank 08 buffer chamber plays a buffering role and can alternately charge the direct reduced iron. into two pressurized discharge bins 09; each of the two pressurized discharge bins 09 is provided with a material flow cut-off valve at the lower part, and the material flow cut-off valve switch is used to control the direct reduced iron to be alternately discharged into the direct reduced iron tank 19.

Hydrogen-based reducing gas is used as a supplementary gas source. The supplementary gas source is controlled at about 10% of the participating reducing gas volume. The supplementary gas is injected from the cone of the shaft furnace reactor 01, flows upward, and merges with the circulating gas to form reducing gas; the reducing gas and After the reaction of high-quality pellets, the waste gas is discharged from the top of the shaft furnace reactor 01. The waste gas discharged from the top passes through the waste heat recovery system 02 to recover heat, the cooling and dust removal system 03 for purification, the compressor system is pressurized to provide circulation power, and the CO ₂ removal system After 05 removes excess CO ₂ and heating furnace 06 provides the heat source for the reduction reaction, it has the reduction capability again. After the circulating gas has the reduction capability, it is injected from the middle of the shaft furnace reactor 01 to form a cycle.

The direct reduced iron discharged from the pressurized discharge bin 09 has a temperature of 500-600°C and is loaded into a direct reduced iron tank 19. The direct reduced iron in the tank is transported to the electric furnace workshop by train and used in the electric furnace for steelmaking.

The outer shell of the direct reduced iron tank 19 is made of cast iron, and the interior is made of masonry. The masonry method is two layers. The side close to the cast iron shell is made of heat-insulating bricks, and the layer contacting the direct reduced iron is made of wear-resistant castables. The direct reduction iron tank 19 is provided with a sliding cover 15. The sliding cover 15 is made of cast iron. The sliding cover 15 is in contact with the edge of the direct reduction iron tank 19 through a chute. The loading and unloading can move along the slot. The inside of the sliding cover 15 is also The masonry is carried out in two layers. The side close to the cast iron shell is made of heat-insulating bricks, and the layer in contact with the direct reduced iron is made of wear-resistant castables. The sliding cover 15 and the direct reduction iron can 19 must be tightly engaged, and the masonry size requirements are strict, so that the sealing and heat preservation effect can be achieved.

Since direct reduced iron is prone to re-oxidation when it comes into contact with air under high temperature conditions, a nitrogen charging device is provided on the sliding cover 15 of the direct reduced iron tank. By filling nitrogen, the atmosphere in the tank is inert, so that the direct reduced iron is isolated from the air and does not Will occur in the oxidation phenomenon. The nitrogen filling device is equipped with a stamping valve and a pressure reducing valve. The stamping valve presses the iron tank to protect the direct reduced iron from reacting; the pressure reducing valve releases pressure from the iron tank and is used when loading and unloading the direct reduced iron.

The direct reduction iron can 19 is transported to the electric furnace workshop for steelmaking using a direct reduction iron tank truck 17, and a nitrogen storage tank 18 is provided on the direct reduction iron tank truck 17 as a gas source for nitrogen charging.

After using the direct reduction iron tank car 17 to transport the direct reduction iron can 19 to the electric furnace workshop, open the nitrogen pressure reducing valve of the direct reduction iron can 19 to discharge the nitrogen in the tank, and use the overhead crane 20 of the electric furnace workshop to hook the direct reduction iron can Lift the iron can with the lifting lugs 19, then open the sliding cover 15 of the direct reduced iron can along the groove, pour the direct reduced iron in the can into the electric furnace, and use it for steelmaking.

Long-distance transportation can be achieved by transporting direct reduced iron to electric furnaces by train. Nitrogen sealing can ensure that direct reduced iron will not be re-oxidized. The masonry direct reduced iron cans are stored during transportation and can be sealed and insulated. The entire process can be realized Hydrogen-based direct reduced iron long-distance hot charging electric furnace.

Claims (5)

1. A method for hydrogen-based direct reduced iron production and long-distance hot charging electric furnace, which is characterized by: including the following steps: Step 1: Load the iron ore pellets into the shaft furnace reactor (01) from the top of the shaft furnace reactor (01), and at the same time pressurize the purified hydrogen-based reducing gas through the hydrogen-based reducing gas pressurizing system (07) Injected into the shaft furnace reactor (01) from the lower part of the shaft furnace reactor (01), the hydrogen-based reducing gas and iron ore pellets flow countercurrently and react in the shaft furnace reactor (01); The waste gas after the reaction between the hydrogen-based reducing gas and the pellets is discharged from the top of the shaft furnace reactor (01), and passes through the waste heat recovery system (02), cooling and dust removal system (03), pressurization system (04), and CO2 removal in sequence System (05) and heating furnace (06) are then injected from the middle of the shaft furnace reactor (01) to form recycling; The direct reduced iron formed after the reaction between hydrogen-based reducing gas and pellets is discharged from the bottom of the shaft furnace reactor (01), enters the discharge buffer tank (08), and is alternately put into the pressurized tank through the discharge buffer tank (08) In the discharge bin (09); Step 2: Orderly discharge the direct reduced iron in the pressurized discharge bin (09) into the direct reduced iron tank (19); Step 3: Transport the direct reduced iron can (19) containing direct reduced iron to the electric furnace workshop by train to be used in the electric furnace for steelmaking. 2. A method for hydrogen-based direct reduced iron production and long-distance hot charging electric furnace according to claim 1, characterized in that: in the third step, the train transports the direct reduced iron can (19) to the direct The reduced iron tank (19) is filled with nitrogen to inert the atmosphere in the direct reduced iron tank (19). 3. A method for hydrogen-based direct reduced iron production and long-distance hot charging electric furnace according to claim 2, characterized in that: the direct reduced iron tank (19) is provided with a sliding cover (15), and nitrogen gas passes through it. The storage tank (18), nitrogen pressure valve (14) and sliding cover (15) are charged into the direct reduced iron tank (19). 4. A method for hydrogen-based direct reduced iron production and remote hot charging electric furnace according to claim 1, characterized in that: in step two, the temperature of the direct reduced iron discharged from the pressurized discharge bin (09) is 500~600℃. 5. A method for producing hydrogen-based direct reduced iron and long-distance hot charging electric furnace according to claim 1, characterized in that: in the step one, the purified hydrogen-based reducing gas passes through a hydrogen-based reducing gas pressurizing system. (07) After pressurization, part of it is injected into the shaft furnace reactor (01) from the lower part of the shaft furnace reactor (01), and the other part is used as fuel gas by the heating furnace (06).