Plasma heating hydrogen-rich direct reduction ironmaking system and method

Abstract

The invention provides a plasma heating hydrogen-rich direct reduction ironmaking system and method. The system comprises a plasma shaft furnace, a heat exchanger, a washer, a desulfurization device, a dehydration device and a pressurization device, the plasma shaft furnace comprises a feeding area, a reduction area, a blanking area and a plasma heating area from top to bottom; the plasma heating area is provided with a hydrogen plasma torch, a thermal reduction gas circulation outlet and a hydrogen inlet; and the hydrogen plasma torch is used for heating and ionizing hydrogen entering from the hydrogen inlet. According to the system and method, the green electricity hydrogen plasma torch is adopted for heating and ionizing hydrogen, then sponge iron is heated and reduced to produce molten iron, compared with a traditional hydrogen heating mode, the heating speed is high, the temperature is high, carbon-containing fuel is not combusted, safety and hydrogen embrittlement are achieved, compared with a traditional shaft furnace for producing sponge iron, low-quality ore can be adopted for producing molten iron, and the production cost is low. The control is convenient.

Description

Technical Field

[0001] The present invention relates to a system and method for directly reducing iron by plasma heating hydrogen-rich gas, belonging to the technical field of iron and steel metallurgy. Background Art

[0002] In the long process of steel production (blast furnace ironmaking + converter steelmaking), the potential for further reducing CO 2 , 2 , 2 , 2 , 2 , 2 , 2 , 2 , 2 emissions is very limited, and new breakthrough processes must be found to solve the problem of high CO 2 emissions in the steel industry. The CO 2 emissions per ton of steel produced by the short process are much lower than those of the long process. As an ideal green metallurgy model, the hydrogen metallurgy process is generally a non-blast furnace ironmaking process mainly represented by gas-based shaft furnace direct reduction, where the hydrogen content in the reducing gas entering the furnace is greater than 55% to reduce iron ore to produce DRI.

[0003] Hydrogen metallurgy has the following advantages: (1) Fast reaction rate: H 2 as a reducing gas has the advantages of fast mass transfer rate, good anti-bonding property, large rate constant, and green reduction products; at high temperatures, the reduction ability of H 2 is higher than that of CO, and the reaction equilibrium concentration is lower than that of CO. At the same temperature, the higher the H 2 content in the reducing atmosphere, the greater the reduction reaction rate. (2) Clean products: Thermodynamically, it is difficult for other elements to be reduced by hydrogen except iron, laying a foundation for the production of pure steel; and hydrogen reduction does not use solid reducing agents, with less P, S, etc. brought in, and fewer impurities in the steelmaking process. (3) Low environmental load: The product of hydrogen metallurgy is water, which can not only reduce or even avoid air pollution by CO 2 , and the reduction products are easy to remove, and energy and water resources can be recycled.

[0004] Currently, the world's advanced direct reduced iron technology is gas-based shaft furnace direct reduction technology, which mainly uses natural gas as raw material. After being converted into a gas rich in H 2 and CO, it directly undergoes solid-state reduction with iron ore at high temperatures to produce sponge iron. The inevitable trend of reducing CO 2 emissions in the steel industry is to develop hydrogen metallurgy. Using all-hydrogen ironmaking can utilize the chemical energy of hydrogen, but the heat energy of the system is insufficient. If other fuels are used for heating, it will inevitably increase carbon emissions. While using green electricity heating and hydrogen smelting can utilize the chemical energy of hydrogen without increasing carbon emissions. Using hydrogen plasma torch heating to produce sponge iron is an optimal technical route for carbon emission reduction and an important direction suitable for the development of new ironmaking technologies in China.

[0005] Generally speaking, the Midrex and HYL methods in the gas-based shaft furnace process have an absolute advantage. With the development of technology, the requirements for reducing gas are more extensive, and hydrogen-rich, pure hydrogen, and pressures greater than 0.1 Mpa can all be used. When using pure hydrogen as the reducing gas, the gas needs to be heated. Traditional heating methods generally use fuel combustion or electric heating. When using the fuel combustion method, the flue gas is bound to contain a large amount of carbon dioxide, increasing carbon emissions. Moreover, when heating pure hydrogen, hydrogen embrittlement is likely to occur, posing a great challenge to the material of the heating furnace, resulting in limited heating temperature. When using the electric heating method, especially green electricity, it reduces the CO 2 generated by fuel combustion. However, the development of pure hydrogen smelting is restricted by the limitations of the heating furnace material and heating temperature. Traditional MIDREX and ENERGIRON shaft furnaces are divided into a top feeding system, a reduction system, a cooling system, and a discharging system. Among them, the reduction system occupies a relatively small height of the entire shaft furnace, while the cooling system and the discharging system account for a large proportion, resulting in energy waste and complex control. Based on this, it is necessary to develop a direct reduction ironmaking system and method with green electricity heating, simple control, and fewer restrictions on hydrogen heating.

[0006] CN115522009A discloses a pure hydrogen plasma smelting reduction ironmaking method, which includes the following steps: S1, loading iron ore into a smelting furnace and discharging the air in the smelting furnace; S2, using nitrogen or inert gas as the arc starting medium and starting a hydrogen plasma torch, and inputting the high-temperature nitrogen or inert gas plasma flame generated by the hydrogen plasma torch into the smelting furnace from the lower side of the smelting furnace to heat the temperature in the smelting furnace to 400 - 500 °C; S3, gradually increasing the flow rate of pure H 2 gas input into the hydrogen plasma torch, and gradually reducing the input amount of nitrogen or inert gas. Utilize the easy ionization characteristic of nitrogen or inert gas to keep the high-temperature flame stable. After the H 2 gas flow rate is stable and can be stably ionized to form a stable arc, completely switch to H 2 as the working gas, and use the high-temperature H 2 plasma flame generated by the ion torch to heat and reduce the iron ore to form molten iron. This method has pure H 2 O steam as the exhaust gas, reducing the emissions of greenhouse gas CO 2 . However, this method is a pure hydrogen plasma smelting reduction ironmaking method, which is carried out in a smelting furnace, and the exhaust gas is directly discharged, wasting hydrogen resources.

[0007] CN115044718A discloses a method for heating coal gas by a plasma torch. The method includes the following steps: S1: Inputting coal gas into the plasma torch for heating; S2: Passing the heated coal gas into a blast furnace to reduce iron oxides. This patent application also discloses the equipment for heating coal gas by a plasma torch, as well as the application of this method or equipment in blast furnace ironmaking. This method or equipment can use a high-power plasma torch to heat coal gas, with the coal gas having a fast temperature rise, avoiding the problem of carbon deposition, overcoming technical biases, reducing the generation of nitrogen and sulfur compounds, reducing environmental pollution caused by the metallurgical industry, and having a high thermoelectric efficiency. The technical solution of this patent application mainly uses a hydrogen plasma torch to heat coal gas for blast furnace ironmaking, belonging to the category of the long blast furnace process, with carbon emissions higher than those of the short-process shaft furnace process, and unable to fundamentally solve the problem of high CO 2 emissions. Summary of the Invention

[0008] To solve the problems of relatively high carbon emissions in ironmaking, unsafe hydrogen heating, heat waste in traditional shaft furnaces, and complex control, the purpose of the present invention is to provide a system and method for plasma heating of hydrogen-rich direct reduction ironmaking. By using a hydrogen plasma torch to heat molten sponge iron, hydrogen gas heated rapidly in molten iron water, and the ionized hydrogen gas is directly sent to the reduction section for smelting reactions.

[0009] To achieve the above object, the present invention provides a system for plasma heating of hydrogen-rich direct reduction ironmaking. Among them, the system for plasma heating of hydrogen-rich direct reduction ironmaking includes: a plasma shaft furnace, a heat exchanger, a scrubber, a desulfurization device, a dehydration device, and a pressurization device; where:

[0010] The plasma shaft furnace includes a feeding area, a reduction area, a blanking area, and a plasma heating area from top to bottom;

[0011] The reduction area is provided with a top gas outlet, and the top gas outlet is connected to the inlet of the first heat exchange channel of the heat exchanger;

[0012] The plasma heating area is provided with a hydrogen plasma torch, a hot reducing gas circulation outlet, a hydrogen gas inlet, a hot reducing gas discharge outlet, a slag outlet, and a molten iron outlet;

[0013] The outlet of the first heat exchange channel of the heat exchanger, the scrubber, the desulfurization device, the dehydration device, the pressurization device, and the inlet of the second heat exchange channel of the heat exchanger are connected in sequence; a hydrogen gas supplement inlet is provided on the connecting pipeline between the pressurization device and the inlet of the second heat exchange channel of the heat exchanger;

[0014] The outlet of the second heat exchange channel of the heat exchanger is connected to the hydrogen plasma torch through the hydrogen inlet, and the hydrogen plasma torch is used to heat and ionize the incoming hydrogen. Among them, the outlet of the hot reducing gas circulation is communicated with the pipeline between the outlet of the second heat exchange channel of the heat exchanger and the hydrogen plasma torch.

[0015] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the feeding area is provided with a feeding bin and an iron ore inlet, and the feeding bin adds iron ore into the plasma shaft furnace through the iron ore inlet.

[0016] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, the first heat exchange channel of the heat exchanger is connected to the top gas outlet of the plasma shaft furnace. After the top gas leaves the plasma shaft furnace, it enters the first heat exchange channel. The second heat exchange channel of the heat exchanger is connected to the outlet of the pressurizing device. The top gas (process gas) after being pressurized by the pressurizing device and the supplemented hydrogen form a mixed gas and enter the second heat exchange channel. Heat exchange can be achieved between the first heat exchange channel and the second heat exchange channel to heat the mixed gas.

[0017] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the reduction area is further provided with a perforated flap valve.

[0018] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the discharging area is provided with a conical discharging device, a sleeve discharging pipe, and a reducing gas inlet; the reduction area is connected to the discharging area through the sleeve discharging pipe and the conical discharging device; among them, the conical discharging device is arranged above the sleeve discharging pipe, and the reducing gas inlet is located at the top of the inner pipe of the sleeve discharging pipe.

[0019] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the middle part of the conical discharging device is provided with air holes.

[0020] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the conical discharging device is of a fixed structure or a rotary structure.

[0021] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the inner pipe of the sleeve discharging pipe is provided with openings in the reduction area, and the annular gap between the inner pipe and the outer pipe of the sleeve discharging pipe is a sponge iron channel.

[0022] The plasma shaft furnace of the present invention consists of a perforated slide valve and a conical feeding device to form a feeding and gas supply device, which can control the falling of sponge iron; during stable operation, the perforated slide valve is normally open, and the feeding rate in the reduction zone can be controlled through the conical feeding device to disperse the reducing gas. When the reaction situation is relatively stable, the perforated slide valve can be normally open. When adjustment is required, the opening degree of the valve is controlled to control the falling rate of the furnace charge and does not hinder the entry of the reducing gas.

[0023] In the above-mentioned system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the conical feeding device is of a rotary structure, which is fixed to the furnace wall of the plasma shaft furnace and is internally provided with a rotating mechanism, enabling the conical feeding device to rotate. The tip of the conical part of the conical feeding device faces upward, and several air holes are distributed in the tip part. There is a certain gap between both sides of the conical part and the inner wall of the plasma shaft furnace, and the sponge iron can move downward along the periphery of the conical part and thus fall into the plasma heating zone. The high-temperature hydrogen-rich gas (i.e., the reducing gas) formed in the plasma heating zone rises through the air holes in the inner pipe of the sleeve feeding pipe and enters the lower part of the conical part of the conical feeding device, and is dispersed into the reduction zone through the air holes in the conical part to heat and reduce the iron ore.

[0024] In the above-mentioned system for plasma heating hydrogen-rich direct reduction ironmaking, the thermal reduction gas circulation outlet of the plasma heating zone is connected to the process gas pipeline, which can circulate and heat hydrogen to meet the reaction requirements.

[0025] In the above-mentioned system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the inner wall of the plasma heating zone is also provided with refractory materials.

[0026] In the above-mentioned system for plasma heating hydrogen-rich direct reduction ironmaking, the thermal reduction gas discharge port is used to release the thermal reduction gas to the outside of the plasma shaft furnace.

[0027] In the above-mentioned system for plasma heating hydrogen-rich direct reduction ironmaking, the hydrogen plasma torch is used to inject high-temperature hydrogen into the plasma shaft furnace, and it is connected to the outlet of the second heat exchange pipeline of the heat exchanger.

[0028] In the above-mentioned system for plasma heating hydrogen-rich direct reduction ironmaking, the slag outlet is used for slag discharge.

[0029] In the above-mentioned system for plasma heating hydrogen-rich direct reduction ironmaking, the molten iron outlet is used to output molten iron. Preferably, the molten iron outlet is connected to a molten iron ladle.

[0030] In the above-mentioned system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the plasma heating zone is provided with hydrogen spray guns, and the number of the hydrogen spray guns ≥ 1. The hydrogen spray guns are used to supplement hydrogen additionally and adjust the temperature of the plasma heating zone.

[0031] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the number of the thermal reduction gas discharge ports ≥ 1.

[0032] The temperature and the reaction gas volume of the reaction can be adjusted through the hydrogen gas lance and the thermal reduction gas discharge port in the plasma heating zone.

[0033] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the hydrogen plasma torches are arranged around the heating zone, and the number of the hydrogen plasma torches ≥ 2.

[0034] In the above system for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the number of the thermal reduction gas circulation outlets ≥ 1.

[0035] The present invention also provides a method for plasma heating hydrogen-rich direct reduction ironmaking. Among them, this method for plasma heating hydrogen-rich direct reduction ironmaking is carried out through the above system for plasma heating hydrogen-rich direct reduction ironmaking, and it includes the following steps:

[0036] Iron ore enters from the upper part of the plasma shaft furnace, and the high-temperature hydrogen-rich gas flows from bottom to top and contacts the iron ore, and the reduction reaction of the iron ore occurs to obtain sponge iron, water and top gas;

[0037] The top gas exchanges heat, cools down, removes dust, desulfurizes, dehydrates and is pressurized outside the plasma shaft furnace, and then is mixed with supplementary hydrogen to obtain a mixed gas. After the mixed gas exchanges heat with the top gas from the plasma shaft furnace, it enters the plasma shaft furnace and is heated and ionized by the hydrogen plasma torch;

[0038] The mixed gas after being heated and ionized by the hydrogen plasma torch enters the molten iron layer in the plasma heating zone, and continues to reduce and melt the sponge iron from the reduction zone. The high-temperature hydrogen-rich gas obtained after the reaction passes through the slag layer and enters the reduction zone.

[0039] In the above method for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the temperature of the top gas (or process gas) after heat exchange and cooling and dust removal is reduced from 300 - 600 °C to below 40 °C, and then it enters the desulfurization device.

[0040] In the above method for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the desulfurization is wet desulfurization or dry desulfurization, and the sulfur content of the top gas after desulfurization ≤ 10 ppmv.

[0041] In the above method for plasma heating hydrogen-rich direct reduction ironmaking, preferably, the dehydration adopts one or a combination of several of centrifugal separation, adsorption dehydration and freeze dehydration.

[0042] In the above method for directly reducing iron by plasma heating with hydrogen-rich gas, preferably, the pressurization is to pressurize the dehydrated top gas to ≥ 0.1 MPa and then mix it with the supplemented hydrogen to obtain a mixed gas.

[0043] In the above method for directly reducing iron by plasma heating with hydrogen-rich gas, preferably, the temperature of the heat-exchanged mixed gas (i.e., hydrogen) is ≥ 200 °C, more preferably 200 - 500 °C. This mixed gas enters the molten iron layer after being ionized by heating with a hydrogen plasma torch.

[0044] In the above method for directly reducing iron by plasma heating with hydrogen-rich gas, the heat-exchanged mixed gas enters the hydrogen plasma torch. Preferably, the reducing gas component in the mixed gas

[0045] In the above method for directly reducing iron by plasma heating with hydrogen-rich gas, preferably, the power of the hydrogen plasma torch is ≥ 200 kW, more preferably ≥ 2 MW. Using a hydrogen plasma torch to ionize and heat hydrogen has a high heating temperature, can reduce potential safety hazards, and is easy to control.

[0046] In the above method for directly reducing iron by plasma heating with hydrogen-rich gas, preferably, the reaction temperature in the plasma heating zone (i.e., the reaction temperature between molten iron and hydrogen) is ≥ 1500 °C.

[0047] In the above method for directly reducing iron by plasma heating with hydrogen-rich gas, preferably, the temperature of the high-temperature hydrogen-rich gas is ≥ 1000 °C, more preferably ≥ 1100 °C.

[0048] In the above method for directly reducing iron by plasma heating with hydrogen-rich gas, the hot sponge iron is directly fed into the plasma heating zone without cooling, which can save energy.

[0049] In the above method for directly reducing iron by plasma heating with hydrogen-rich gas, preferably, the metallization rate in the reduction zone of the plasma shaft furnace is ≥ 50%, and the metallization rate in the plasma heating zone is ≥ 95%.

[0050] In the above method for directly reducing iron by plasma heating with hydrogen-rich gas, the molten iron in the plasma heating zone is intermittently discharged through a molten iron ladle, and the intermittent time is greater than 5 h; the slag layer is continuously discharged.

[0051] The present invention mainly aims at problems such as relatively high carbon emissions in ironmaking, unsafe hydrogen heating, waste of heat in the cooling section of traditional shaft furnaces, the need for high-quality iron ore, and complex control. Using green electricity, it heats and ionizes hydrogen with a hydrogen plasma torch, directly sends the hot hydrogen to shaft furnace ironmaking, and is further heated in the molten iron, then enters the reduction zone to react with iron ore to form sponge iron; the sponge iron enters the heating zone through a conical feeding device, and the sponge iron is heated, reduced, and melted under high-temperature hydrogen conditions to produce slag and molten iron, reducing the cooling section and discharging section of the traditional shaft furnace; the hydrogen that is rapidly heated in the molten iron and the ionized hydrogen are directly sent to the reduction section for smelting reaction. The top gas obtained during the reduction process (i.e., unreacted hydrogen) is sent to the plasma melting section for reduction heating after heat exchange, washing, dust removal, desulfurization, and dehydration, solving problems such as difficult hydrogen heating, hydrogen embrittlement, waste of heat in the cooling section of the shaft furnace, and difficult control of furnace charge, and having advantages such as nearly zero CO 2 emissions, high reaction efficiency, and environmental friendliness.

[0052] The innovations and beneficial effects of the plasma heating hydrogen-rich direct reduction ironmaking system and method of the present invention are as follows:

[0053] 1. The plasma heating hydrogen-rich direct reduction ironmaking system and method of the present invention use a green electricity hydrogen plasma torch to heat and ionize hydrogen, and then heat and reduce sponge iron to produce molten iron. Compared with traditional hydrogen heating methods, it has a fast heating rate, a high heating temperature, does not burn carbon-containing fuels, is safe without hydrogen embrittlement, and has low carbon emissions.

[0054] 2. The plasma heating hydrogen-rich direct reduction ironmaking system and method of the present invention remove the cooling section of the traditional shaft furnace, and the hot sponge iron directly enters the plasma heating zone, saving energy.

[0055] 3. The plasma heating hydrogen-rich direct reduction ironmaking system and method of the present invention control the reduction feeding rate of iron ore by controlling the perforated gate valve and the conical feeding device, with simple control and low failure rate.

[0056] 4. The top gas treatment process of the plasma heating hydrogen-rich direct reduction ironmaking system and method of the present invention is simple, and the control loop is concise.

[0057] 5. The reaction temperature and reaction gas volume of the plasma heating hydrogen-rich direct reduction ironmaking system and method of the present invention are adjustable, the process is safe and reliable, low-quality iron ore can be used, and the applicable range is wide.

[0058] The technical solution provided by the present invention has the advantages of simple process, rapid heating, convenient control, energy saving, and nearly zero CO 2 emissions, and is a very promising technical route for producing green steel, improving product quality, and enhancing competitiveness. Description of the Drawings

[0059] Figure 1 Schematic diagram of the plasma heating hydrogen-rich direct reduction ironmaking system provided for Example 1.

[0060] Figure 2 Partial structure diagram of the plasma heating zone in the system provided for Example 1.

[0061] Figure 3 Top view of the conical feeding device for Example 1.

[0062] Figure 4 Longitudinal section schematic diagram of the conical feeding device for Example 1.

[0063] Description of main attached drawing reference numerals:

[0064] 1 - Plasma shaft furnace; 2 - Furnace top gas outlet; 3 - Perforated flap valve; 4 - Hot reducing gas discharge port; 5 - Hot reducing gas circulation outlet; 6 - Hydrogen plasma torch; 7 - Slag layer; 8 - Sleeve feeding pipe; 9 - Molten iron layer; 10 - Molten iron ladle; 11 - Refractory material; 12 - Slag outlet; 13 - Hydrogen gas spray gun; 14 - Heat exchanger; 15 - Scrubber; 16 - Desulfurization device; 17 - Dewatering device; 18 - Pressurizing device; 19 - Conical feeding device; 20 - Feed bin; 21 - Iron ore inlet; 22 - Reducing gas inlet; 23 - Hydrogen gas inlet; 24 - Molten iron outlet; 25 - Hydrogen gas supplementary inlet; 26 - Furnace wall; 1901 - Air hole; 1902 - Support arm; 1903 - Sponge iron channel; 1904 - Ball; 1905 - Track limiting rod. Detailed implementation manners

[0065] For a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solution of the present invention will be described in detail below, but it should not be construed as a limitation on the implementable scope of the present invention.

[0066] Example 1

[0067] This example provides a plasma heating hydrogen-rich direct reduction ironmaking system, the structure of which is as Figure 1 shown. The system includes: plasma shaft furnace 1, heat exchanger 14, scrubber 15, desulfurization device 16, dewatering device 17, pressurizing device 18, etc.; where:

[0068] The plasma shaft furnace 1 includes a feeding zone, a reduction zone, a feeding zone, and a plasma heating zone from top to bottom;

[0069] The feeding zone is provided with a feed bin 20 and an iron ore inlet 21, and the feed bin 20 adds iron ore into the plasma shaft furnace 1 through the iron ore inlet 21;

[0070] The reduction zone is provided with a furnace top gas outlet 2 and a perforated flap valve 3;

[0071] The blanking area is provided with a conical blanking device 19, a sleeve blanking pipe 8, and a reducing gas inlet 22. The conical blanking device 19 is arranged above the sleeve blanking pipe 8; the reduction area is connected to the blanking area through the sleeve blanking pipe 8 and the conical blanking device 19; the sleeve blanking pipe 8 is composed of an inner pipe and an outer pipe. The lower end of the inner pipe is located inside the plasma heating area and is provided with openings to facilitate the entry of reducing gas (high-temperature hydrogen-rich gas) into the inner pipe. The top opening of the inner pipe is the reducing gas inlet 22, which is used to allow the reducing gas to enter the conical blanking device 19;

[0072] The conical blanking device 19 is generally conical in shape, with the tip of the conical part facing upward and provided with a number of air holes 1901 (as Figure 3 shown), which are used to allow the reducing gas to enter the upper reduction area. These air holes 1901 can also play a role in dispersing the reducing gas; the four peripheral edges of the conical blanking device 19 are connected to the furnace wall 26 of the plasma shaft furnace 1 through a number of support arms 1902. Moreover, there is a certain gap between the conical blanking device 19 and the furnace wall 26, namely the sponge iron channel 1903. The sponge iron can move downward along the periphery of the conical part and then fall into the annulus between the inner pipe and the outer pipe of the sleeve blanking pipe 8 through the sponge iron channel 1903, and then fall into the plasma heating area; the conical blanking device 19 can rotate. The upper surface of each support arm 1902 at the bottom is respectively provided with a pit, and a ball 1904 is arranged in the pit. At the position corresponding to the ball 1904 on the inner wall of the conical blanking device 19, there is a track limiting rod 1905. The conical blanking device 19 can rotate driven by a motor, as Figure 4 shown;

[0073] The plasma heating area is provided with refractory material 11, a hydrogen plasma torch 6, a hot reducing gas discharge port 4, a hot reducing gas circulation outlet 5, a hydrogen inlet 23, a slag outlet 12, and a molten iron outlet 24, as Figure 2 shown; the refractory material 11 is arranged on the inner wall of the plasma heating area; the slag layer 7 in the plasma heating area is discharged through the slag outlet 12, and the molten iron layer 9 is connected to the molten iron ladle 10 through the molten iron outlet 24;

[0074] The furnace top gas outlet 2 is connected to the inlet of the first heat exchange channel of the heat exchanger 14. The outlet of the first heat exchange channel of the heat exchanger 14, the scrubber 15, the desulfurization device 16, the dehydration device 17, the pressurization device 18, and the inlet of the second heat exchange channel of the heat exchanger 14 are connected in sequence;

[0075] A hydrogen supplement inlet 25 is arranged on the connecting pipe between the pressurization device 18 and the inlet of the second heat exchange channel of the heat exchanger 14. This hydrogen supplement inlet 25 is used to supplement hydrogen;

[0076] The outlet of the second heat exchange channel of the heat exchanger 14 is connected to the plasma heating zone through the hydrogen inlet 23, and a hydrogen plasma torch 6 is provided at the hydrogen inlet 23 for heating and ionizing hydrogen;

[0077] A number of hydrogen spray guns 13 are provided in the plasma heating zone, such as Figure 2 shown. The hydrogen spray gun 13 and the thermal reducing gas discharge port 4 are combined to control the reaction temperature and reaction gas volume in the plasma heating zone;

[0078] The thermal reducing gas circulation outlet 5 of the plasma heating zone is communicated with the pipeline between the outlet of the second heat exchange channel of the heat exchanger 14 and the hydrogen plasma torch 6 for circulating and heating hydrogen.

[0079] Example 2

[0080] This example provides a method for plasma heating hydrogen-rich direct reduction ironmaking, which is carried out by using the plasma heating hydrogen-rich direct reduction ironmaking system of Example 1. The method includes:

[0081] The iron ore is placed in the feed bin 20 in the upper feeding area of the plasma shaft furnace 1 and enters the reduction area of the plasma shaft furnace 1 through the iron ore inlet 21;

[0082] The high-temperature hydrogen-rich gas from the plasma heating zone of the plasma shaft furnace 1 flows from bottom to top, contacts the iron ore in the reduction area, and undergoes the reduction reaction of the iron ore to obtain sponge iron, water and top gas;

[0083] The top gas enters the first heat exchange channel of the heat exchanger 14 through the top gas outlet 2, then enters the scrubber 15 for washing, cooling and dust removal, then enters the desulfurization device 16 for desulfurization until the sulfur content ≤ 10 ppmv, then enters the dehydration device 17 to remove moisture, then enters the pressurization device 18 for pressurization greater than 0.1 MPa, and then is mixed with the hydrogen supplemented through the hydrogen supplement inlet 25 to obtain a mixed gas;

[0084] The mixed gas enters the second heat exchange channel of the heat exchanger 14 and exchanges heat with the gas in the first heat exchange channel. The mixed gas is heated to >300°C, and then enters the hydrogen plasma torch 6 through the hydrogen inlet 23, and is heated and ionized by the hydrogen plasma torch 6, and enters the plasma vertical furnace 1. The high-temperature hydrogen and ions heat, reduce and melt the sponge iron, and the heating electricity uses green electricity; the reaction temperature of the heating zone is ~1800°C, and the heated hydrogen enters the molten iron layer 9. The sponge iron and hydrogen further react, and the metallization rate is increased to more than 95%. The temperature of the hydrogen after the reaction is greater than 1000°C, and the sponge iron becomes molten iron. The molten iron in the molten iron layer 9 enters the molten iron tank 10 and is intermittently sent to the subsequent steelmaking link; hydrogen is supplemented by the hydrogen spray gun 13 to adjust the temperature and gas volume of the plasma heating zone; part of the reducing gas can enter the pipeline between the heat exchanger 14 and the hydrogen plasma torch 6 through the hot reducing gas circulation outlet 5 to heat the mixed gas and increase the gas temperature;

[0085] The unreacted reducing gas (high-temperature hydrogen-rich gas) passes through the slag layer 7 and enters the pores at the lower part of the inner tube of the sleeve feeding tube 8, and enters the bottom of the conical feeding device 19 along the inner tube, and enters the reduction zone through the pores at the conical part of the conical feeding device 19;

[0086] The sponge iron obtained by the reaction of the reducing gas with the iron ore in the reduction zone falls into the annular gap between the inner tube and the outer tube of the sleeve feeding tube 8 along the conical feeding device 19, and thus enters the plasma heating zone;

[0087] The plasma heating zone can release unqualified gas through the hot reduction gas release port 4, and discharge gas when the fault stops;

[0088] The plasma shaft furnace can control the drop of sponge iron through the perforated gate valve 3 and the conical unloading device 19 in the reduction zone. During stable operation, the perforated gate valve 3 is always open, and the conical unloading device 19 controls the unloading rate of the reduction section to disperse the reducing gas;

[0089] The slag in the slag layer 7 can be discharged through the slag outlet 12.​

Claims

1. A plasma heating hydrogen-rich direct reduction ironmaking system, characterized in that: The plasma-heated hydrogen-rich direct reduction ironmaking system comprises: a plasma vertical furnace (1), a heat exchanger (14), a scrubber (15), a desulfurization device (16), a dehydration device (17), and a pressurizing device (18); wherein: The plasma vertical furnace (1) comprises, from top to bottom, a feeding zone, a reduction zone, a feeding zone, and a plasma heating zone; The reduction zone is provided with a top gas outlet (2), and the top gas outlet (2) is connected to the inlet of the first heat exchange channel of the heat exchanger (14); The plasma heating zone is provided with a hydrogen plasma torch (6), a hot reducing gas circulation outlet (5), a hydrogen inlet (23), a hot reducing gas release outlet (4), a slag outlet (12), and a molten iron outlet (24); The outlet of the first heat exchange channel of the heat exchanger (14), the scrubber (15), the desulfurization device (16), the dehydration device (17), the pressurizing device (18), and the inlet of the second heat exchange channel of the heat exchanger (14) are connected in sequence; a hydrogen supplement inlet (25) is provided on the connecting pipe between the pressurizing device (18) and the inlet of the second heat exchange channel of the heat exchanger (14); The outlet of the second heat exchange channel of the heat exchanger (14) is connected to the hydrogen plasma torch (6) through the hydrogen inlet (23), and the hydrogen plasma torch (6) is used to heat and ionize the hydrogen entering through the hydrogen inlet (23), wherein the hot reducing gas circulation outlet (5) is connected to the pipeline between the outlet of the second heat exchange channel of the heat exchanger (14) and the hydrogen plasma torch (6).

2. The plasma heating hydrogen-rich direct reduction ironmaking system according to claim 1 is characterized in that: The feed zone is provided with a feed bin (20) and an iron ore inlet (21), and the feed bin (20) adds iron ore into the plasma shaft furnace (1) through the iron ore inlet (21).

3. The plasma heating hydrogen-rich direct reduction ironmaking system according to claim 1 is characterized in that: The reduction zone is also provided with a plug valve (3) with a hole.

4. The plasma heating hydrogen-rich direct reduction ironmaking system according to claim 1 is characterized in that: The material discharge area is provided with a conical material discharge device (19), a sleeve material discharge pipe (8), and a reducing gas inlet (22); The reduction zone is connected to the unloading zone via a sleeve unloading pipe (8) and the conical unloading device (19); Wherein, the conical feeding device (19) is arranged above the sleeve feeding pipe (8), and the reducing gas inlet (22) is located at the top of the inner tube of the sleeve feeding pipe (8).

5. The plasma heating hydrogen-rich direct reduction ironmaking system according to claim 4 is characterized in that: The middle part of the conical feeding device (19) is provided with air holes.

6. The plasma heating hydrogen-rich direct reduction ironmaking system according to claim 4 is characterized in that: The inner tube of the sleeve feed pipe (8) is provided with an opening in the reduction zone, and the annular gap between the inner tube and the outer tube of the sleeve feed pipe (8) is a sponge iron channel.

7. The plasma heating hydrogen-rich direct reduction ironmaking system according to claim 1 is characterized in that: The inner wall of the plasma heating zone is also provided with refractory material (11).

8. A plasma heating hydrogen-rich direct reduction ironmaking method, characterized in that: The method for plasma heating hydrogen-rich direct reduction ironmaking is carried out by the plasma heating hydrogen-rich direct reduction ironmaking system according to any one of claims 1 to 7, and comprises the following steps: Iron ore enters from the upper part of the plasma vertical furnace (1), and high-temperature hydrogen-rich gas flows from the bottom to the top to contact the iron ore to cause a reduction reaction of the iron ore, thereby obtaining sponge iron, water and top gas; The top gas is subjected to heat exchange, cooling and dust removal, desulfurization, dehydration and pressurization outside the plasma vertical furnace (1), and then mixed with supplementary hydrogen to obtain a mixed gas. The mixed gas enters the plasma vertical furnace (1) after heat exchange with the top gas from the plasma vertical furnace (1), and is heated and ionized by the hydrogen plasma torch (6); The hydrogen gas heated and ionized by the hydrogen plasma torch (6) enters the molten iron layer in the plasma heating zone, and continues to reduce and melt the sponge iron from the reduction zone. The high-temperature hydrogen-rich gas obtained after the reaction passes through the slag layer and enters the reduction zone.

9. The method for plasma heating hydrogen-rich direct reduction ironmaking according to claim 8, characterized in that: The sulfur content of the desulfurized top gas is ≤10ppmv.

10. The method for plasma heating hydrogen-rich direct reduction ironmaking according to claim 8, characterized in that: The pressurization is to pressurize the dehydrated furnace top gas to ≥0.1MPa.

11. The method for plasma heating hydrogen-rich direct reduction ironmaking according to claim 8, characterized in that: The temperature of the mixed gas after heat exchange is ≥200℃.

12. The plasma heating hydrogen-rich direct reduction ironmaking method according to claim 8, characterized in that: The temperature of the high-temperature hydrogen-rich gas is ≥1000°C.

13. The method for plasma heating hydrogen-rich direct reduction ironmaking according to claim 8, characterized in that: The metallization rate of the reduction zone of the plasma vertical furnace (1) is ≥50%, and the metallization rate of the plasma heating zone is ≥95%.

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