Circulating fluidized bed hydrogen metallurgy system and method with microwave heating function
By introducing microwave heating and stepwise reduction technology into the circulating fluidized bed hydrogen metallurgy system, the problems of high-temperature agglomeration and flow loss of iron ore powder and low reduction rate were solved, realizing efficient hydrogen utilization and carbon-free metallurgy, and improving the performance of the reduction system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-12
- Publication Date
- 2026-03-13
AI Technical Summary
Existing circulating fluidized bed hydrogen metallurgy technology suffers from problems such as high-temperature agglomeration and loss of iron ore powder, low reduction rate, and low hydrogen utilization rate, which limit its large-scale application.
A microwave heating subsystem is used to pretreat the pre-reduction fluidized bed reactor, which is then combined with a circulating fluidized bed reactor for stepwise reduction. A gas-solid separation device and a return material device are used to achieve a dual enhancement of iron ore powder.
It improves the reduction rate of iron ore powder and the utilization rate of hydrogen, avoids high-temperature adhesion and loss of flow, realizes carbon-free metallurgy, and improves the output and efficiency of the reduction system.
Smart Images
Figure CN121653304A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of iron and steel metallurgy technology, and in particular to a circulating fluidized bed hydrogen metallurgy system and method with microwave heating. Background Technology
[0002] The steel industry is a crucial pillar of the national economy, but also a major consumer of energy and emitter of carbon dioxide. my country's steel industry is dominated by the blast furnace-converter long process, with the blast furnace ironmaking process accounting for 70% of the total energy consumption and carbon emissions. Under the dual-carbon strategy, replacing coal with clean energy is an urgent need for the steel industry to significantly reduce carbon emissions. In 2021, the State Council's "Action Plan for Achieving Carbon Peak by 2030" listed the steel industry as a key area for industrial carbon peaking, pointing out the need to promote clean energy substitution in the steel industry and explore research and demonstration applications of hydrogen metallurgy. In 2022, the Ministry of Industry and Information Technology, the National Development and Reform Commission, and other departments jointly issued the "Implementation Plan for Carbon Peaking in the Industrial Sector," listing carbon peaking in the steel industry as a major action, stating that by 2030, breakthroughs will be achieved in technologies such as hydrogen-rich carbon-cycle blast furnace smelting and hydrogen-based vertical shaft furnace direct reduction iron. Therefore, developing "hydrogen metallurgy" is an inevitable direction for the low-carbon transformation of my country's steel industry. Driven by the dual-carbon strategy, hydrogen-rich blast furnace smelting and gas-based vertical shaft furnace direct reduction have become the mainstream hydrogen metallurgical technologies, and significant progress has been made both domestically and internationally.
[0003] However, both of these routes still rely on iron ore pellets as raw material, especially gas-based shaft furnaces which require high-grade iron ore powder, resulting in limited carbon reduction effects across the entire process. Compared to shaft furnace technology, circulating fluidized bed technology directly uses iron ore powder as raw material, with reducing gas reacting in contact with fluidized iron ore powder. This offers advantages such as a large gas-solid contact area, high reaction efficiency, and low raw material costs, making it a promising direct reduction ironmaking technology and a crucial tool for deep decarbonization in the ironmaking process. Although circulating fluidized bed hydrogen metallurgy technology has attracted considerable attention due to its significant advantages, problems limiting its large-scale application, such as high-temperature agglomeration and flow loss of iron ore powder, low reduction rate, and low hydrogen utilization, have not yet been resolved. Further research is needed to explore circulating fluidized bed systems that can suppress ore powder agglomeration to facilitate the advancement and promotion of hydrogen metallurgy technology. Summary of the Invention
[0004] To address the technical problems of high-temperature agglomeration and flow loss of iron ore powder, low reduction rate, and low hydrogen utilization rate in existing circulating fluidized bed hydrogen metallurgy technologies, this invention provides a circulating fluidized bed hydrogen metallurgy system and method with microwave heating.
[0005] Therefore, the present invention provides the following technical solution: A circulating fluidized bed hydrogen metallurgical system with microwave heating includes a raw material feeding subsystem, a hydrogen compressor, a pre-reduction fluidized bed reactor, a microwave heating subsystem, an electric heating subsystem, a circulating fluidized bed reactor, a hydrogen production subsystem, an air separation subsystem, a nitrogen compressor, a gas-solid separation device, a return material device, and a gas circulation subsystem. The discharge end of the raw material feeding subsystem is connected to the feed inlet of the pre-reduction fluidized bed reactor; the gas outlet of the hydrogen production subsystem is connected to the gas inlet of the hydrogen compressor; the gas outlet of the air separation subsystem is connected to the gas inlet of the nitrogen compressor; and the gas outlets of the hydrogen compressor and the nitrogen compressor merge and are connected to the bottom gas inlet of the pre-reduction fluidized bed reactor. The microwave heating subsystem is surrounded and arranged outside the pre-reduction fluidized bed reactor; the discharge port of the pre-reduction fluidized bed reactor is connected to the feed end of the circulating fluidized bed reactor through a pipeline; the electric heating subsystem is surrounded and arranged outside the riser pipe of the circulating fluidized bed reactor; the discharge end of the circulating fluidized bed reactor is connected to the feed end of the gas-solid separation device; the solid phase discharge end of the gas-solid separation device is connected to the feed end of the return device; and the discharge end of the return device is connected to the feed end of the circulating fluidized bed reactor. The gas circulation subsystem includes a heat exchange device and a dehydration device; the gas phase outlet of the gas-solid separation device is connected to the hot fluid inlet of the heat exchange device, and the hot fluid outlet of the heat exchange device is connected to the inlet of the dehydration device; the gas phase outlet of the dehydration device is connected to the cold fluid inlet of the heat exchange device, and the cold fluid outlet of the heat exchange device is connected to the air inlet of the circulating fluidized bed reactor; the liquid phase outlet of the dehydration device is connected to the water inlet of the water pump. The outlet of the water pump is connected to the inlet of the hydrogen production subsystem.
[0006] Furthermore, the microwave heating subsystem includes a microwave heater and has a cavity structure that is wrapped around the outside of the pre-reduction fluidized bed reactor.
[0007] Furthermore, in the gas circulation subsystem, a dust removal device is connected in series between the heat exchange device and the dehydration device. The gas phase discharged from the gas-solid separation device flows sequentially through the hot fluid channel of the heat exchange device and the dust removal device before entering the dehydration device.
[0008] Furthermore, it also includes a melting pool, the feed end of which is connected to the bottom discharge end of the circulating fluidized bed reactor via a pipeline; the outlet end of the hydrogen compressor is connected to the feed end of the melting pool.
[0009] Furthermore, the hydrogen production subsystem consists of a photovoltaic power generation unit and an alkaline water electrolysis hydrogen production unit, with the photovoltaic power generation unit providing electrical energy to the alkaline water electrolysis hydrogen production unit.
[0010] A hydrogen metallurgical method based on the aforementioned microwave-heated circulating fluidized bed hydrogen metallurgical system includes the following steps: S1. Start the hydrogen production subsystem, power it with its photovoltaic power generation unit, and produce hydrogen using the alkaline water electrolysis hydrogen production unit; at the same time, start the air separation subsystem to separate nitrogen and start the raw material feeding subsystem to feed iron ore powder into the pre-reduction fluidized bed reactor. S2: Nitrogen separated by the air separation subsystem is introduced into the pre-reduction fluidized bed reactor through the nitrogen compressor to maintain an inert atmosphere in the pre-reduction reactor; then the nitrogen input channel is closed, the hydrogen compressor is turned on, and the hydrogen produced by the hydrogen production subsystem is introduced into the pre-reduction fluidized bed reactor. At the same time, the microwave heating subsystem is started to pre-treat the iron ore powder in the pre-reduction fluidized bed reactor with microwave heating. S3. After pretreatment, maintain the flow of hydrogen into the pre-reduction fluidized bed reactor. After preliminary reduction, the iron ore powder in the pre-reduction fluidized bed reactor enters the circulating fluidized bed reactor through the discharge port. Start the electric heating subsystem to heat the riser section of the circulating fluidized bed reactor. The iron ore powder undergoes a reduction reaction in the circulating fluidized bed reactor. The gas-solid mixture after the reaction enters the gas-solid separation device from the discharge end of the circulating fluidized bed reactor. After gas-solid separation, the solid material enters the return device and is sent back to the circulating fluidized bed reactor to continue the reaction until the iron ore powder is completely reduced. S4. The high-temperature reducing tail gas separated by the gas-solid separation unit enters the heat exchange device of the gas circulation subsystem; the high-temperature tail gas flows through the hot fluid channel of the heat exchange device and then enters the dehydration device for dehydration treatment; the dehydrated tail gas enters the cold fluid channel of the heat exchange device for heat absorption and preheating, and the preheated tail gas is sent to the circulating fluidized bed reactor through the cold fluid outlet of the heat exchange device to participate in the reaction; the water removed by the dehydration device is pumped to the alkaline electrolysis water production unit of the hydrogen production subsystem to realize the recycling of water resources.
[0011] Furthermore, in step S2, the microwave frequency of the microwave heating subsystem is 2.45 GHz.
[0012] Furthermore, in step S3, the particle size range of the heated iron ore powder is 0-8 mm; the temperature of the reduction reaction zone in the circulating fluidized bed reactor is 800-950℃, the temperature difference between different parts of the reduction reaction zone in the circulating fluidized bed reactor is 0-80℃, and the apparent fluidization velocity of the circulating fluidized bed is 4-5 m / s.
[0013] Furthermore, in step S4, if the gas circulation subsystem includes a dust removal device, the high-temperature exhaust gas flows through the hot fluid channel of the heat exchange device, first enters the dust removal device to remove dust, and then enters the dehydration device for dehydration treatment; the preheating temperature of the hydrogen gas after dehydration by the dehydration device is 300-450℃.
[0014] Furthermore, in step S3, the direct reduced iron generated in the circulating fluidized bed reactor is transported to the molten pool through its bottom discharge end; hydrogen is introduced into the molten pool through a hydrogen compressor to form a reducing atmosphere and prevent the oxidation of the molten direct reduced iron.
[0015] Advantages and positive effects of the present invention: The iron ore powder in the pre-reduction fluidized bed reactor is pretreated by a microwave heating subsystem. Microwave heating has the characteristics of uniform heat penetration and controllable heating rate, which can avoid the local overheating and softening of iron ore powder and particle agglomeration caused by traditional heating methods. It also avoids the fluidized bed loss problem caused by high temperature agglomeration and ensures the continuity of the reduction reaction.
[0016] By employing a pre-reduction fluidized bed reactor and a circulating fluidized bed reactor for reduction, the reduction process is divided into two steps, extending the contact reaction time between iron ore powder and hydrogen. Simultaneously, a return feed device sends the incompletely reduced solid material after gas-solid separation back to the circulating fluidized bed reactor to participate in the reaction again, avoiding material waste. This improves hydrogen utilization, ultimately achieving a dual increase in both iron ore powder reduction rate and hydrogen utilization rate. This significantly improves the metal reduction rate and increases the output of the reduction system.
[0017] Direct hydrogen reduction of iron ore is a fully hydrogen-based metallurgical technology. Replacing carbon with hydrogen and coke with gas is an important technological direction for the steel industry to achieve carbon neutrality. Circulating fluidized beds have the advantage of good adaptability to iron ore raw materials, and can directly use concentrate powder without sintering process. In addition, compared with traditional vertical shaft furnaces, circulating fluidized beds have the significant advantage of zero carbon dioxide emissions. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of a circulating fluidized bed hydrogen metallurgical system with microwave heating provided by the present invention.
[0020] In the diagram: 1. Air separation subsystem; 2. Nitrogen compressor; 3. Hydrogen production subsystem; 4. Hydrogen compressor; 1'. Circulating fluidized bed reactor; 2'. Gas-solid separation device; 3'. Return material device; 4'. Pre-reduction fluidized bed reactor; 5. Microwave heating subsystem; 6. Electric heating subsystem; 7. Raw material feeding subsystem; 8. Heat exchange device; 9. Dust removal device; 10. Dehydration device; 11. Melting tank; 12. Water pump. Detailed Implementation
[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0022] This invention provides a circulating fluidized bed hydrogen metallurgical system with microwave heating, such as... Figure 1 As shown, it includes a raw material feeding subsystem 7, a hydrogen compressor 4, a pre-reduction fluidized bed reactor 4', a microwave heating subsystem 5, an electric heating subsystem 6, a circulating fluidized bed reactor 1', a hydrogen production subsystem 3, an air separation subsystem 1, a nitrogen compressor 2, a gas-solid separation device 2', a return material device 3', and a gas circulation subsystem.
[0023] The discharge end of the raw material feeding subsystem 7 is connected to the inlet of the pre-reduction fluidized bed reactor 4'; the gas outlet of the hydrogen production subsystem 3 is connected to the gas inlet of the hydrogen compressor 4; the gas outlet of the air separation subsystem 1 is connected to the gas inlet of the nitrogen compressor 2; and the gas outlets of the hydrogen compressor 4 and the nitrogen compressor 2 merge and are connected together to the bottom gas inlet of the pre-reduction fluidized bed reactor 4'.
[0024] The hydrogen production subsystem 3 consists of a photovoltaic power generation unit and an alkaline water electrolysis hydrogen production unit. The photovoltaic power generation unit provides electricity to the alkaline water electrolysis hydrogen production unit.
[0025] The microwave heating subsystem 5 is arranged around the outside of the pre-reduction fluidized bed reactor 4'; the microwave heating subsystem 5 includes a microwave heater and is a cavity structure that is wrapped around the outside of the pre-reduction fluidized bed reactor 4'.
[0026] The discharge port of the pre-reduction fluidized bed reactor 4' is connected to the feed end of the circulating fluidized bed reactor 1' via a pipeline. The electric heating subsystem 6 is arranged around the outside of the riser pipe of the circulating fluidized bed reactor 1'. The discharge end of the circulating fluidized bed reactor 1' is connected to the feed end of the gas-solid separation device 2'. The solid phase discharge end of the gas-solid separation device 2' is connected to the feed end of the return material device 3'. The discharge end of the return material device 3' is connected to the feed end of the circulating fluidized bed reactor 1'.
[0027] The gas circulation subsystem includes a heat exchange device 8 and a dehydration device 10. The gas phase outlet of the gas-solid separation device 2' is connected to the hot fluid inlet of the heat exchange device 8, and the hot fluid outlet of the heat exchange device 8 is connected to the inlet of the dehydration device 10. The gas phase outlet of the dehydration device 10 is connected to the cold fluid inlet of the heat exchange device 8, and the cold fluid outlet of the heat exchange device 8 is connected to the air inlet of the circulating fluidized bed reactor 1'. The liquid phase outlet of the dehydration device 10 is connected to the water inlet of the water pump 12. In the gas circulation subsystem, a dust removal device 9 is connected in series between the heat exchange device 8 and the dehydration device 10. The gas phase discharged from the gas-solid separation device 2' flows sequentially through the hot fluid channel of the heat exchange device 8 and the dust removal device 9 before entering the dehydration device 10.
[0028] The outlet of water pump 12 is connected to the inlet of hydrogen production subsystem 3.
[0029] The hydrogen metallurgical system also includes a molten pool 11, the feed end of which is connected to the bottom discharge end of the circulating fluidized bed reactor 1' via a pipeline; the outlet end of the hydrogen compressor 4 is connected to the feed end of the molten pool 11.
[0030] A hydrogen metallurgical method based on the aforementioned microwave-heated circulating fluidized bed hydrogen metallurgical system includes the following steps: S1. Start the hydrogen production subsystem 3, which is powered by its photovoltaic power generation unit, and use the alkaline water electrolysis hydrogen production unit to produce hydrogen; at the same time, start the air separation subsystem 1 to separate nitrogen, and start the raw material feeding subsystem 7 to feed iron ore powder into the pre-reduction fluidized bed reactor 4'.
[0031] S2: Nitrogen separated by air separation subsystem 1 is introduced into pre-reduction fluidized bed reactor 4' via nitrogen compressor 2 to maintain an inert atmosphere inside pre-reduction reactor 4'; then the nitrogen input channel is closed, hydrogen compressor 4 is turned on, and hydrogen prepared by hydrogen production subsystem 3 is introduced into pre-reduction fluidized bed reactor 4'. At the same time, microwave heating subsystem 5 is started to pre-treat the iron ore powder in pre-reduction fluidized bed reactor 4' with microwave heating; the microwave frequency of microwave heating subsystem 5 is 2.45 GHz.
[0032] S3. After pretreatment, maintain the flow of hydrogen into the pre-reduction fluidized bed reactor 4'. After preliminary reduction, the iron ore powder in the pre-reduction fluidized bed reactor 4' enters the circulating fluidized bed reactor 1' through the discharge port. Start the electric heating subsystem 6 to heat the riser section of the circulating fluidized bed reactor 1', and the iron ore powder undergoes a reduction reaction in the circulating fluidized bed reactor 1'. The iron ore powder entering the circulating fluidized bed reactor 1' can quickly undergo a reduction reaction with hydrogen, and the reaction equation for the reduction reaction is: .
[0033] The gas-solid mixture after the reaction enters the gas-solid separation device 2' from the outlet end of the circulating fluidized bed reactor 1'. After gas-solid separation, the solid phase material enters the return device 3', which sends it back to the circulating fluidized bed reactor 1' to continue the reaction until the iron ore powder is completely reduced. The particle size range of the heated iron ore powder is 0-8 mm. The temperature of the reduction reaction zone in the circulating fluidized bed reactor 1' is 800-950℃. Due to the fluidization and circulation of a large amount of iron ore powder, the temperature in the entire circulating fluidized bed is relatively uniform, and the temperature difference between different parts is controlled within the range of 0-80℃. The apparent fluidization velocity of the circulating fluidized bed is 4-5 m / s.
[0034] The direct reduced iron generated in the circulating fluidized bed reactor 1' will gradually sink to the bottom of the reactor due to the greater specific gravity of iron than iron ore powder. The direct reduced iron generated in the reduction reaction will be continuously or intermittently transported to the molten pool 11 through the bottom discharge end. Hydrogen is introduced into the molten pool 11 through the hydrogen compressor 4 to form a reducing atmosphere and prevent the oxidation of the molten direct reduced iron.
[0035] S4. The high-temperature reduction tail gas separated by the gas-solid separation device 2' enters the heat exchange device 8 of the gas circulation subsystem; the high-temperature reduction tail gas mainly contains unreacted hydrogen, water vapor and dust.
[0036] The high-temperature exhaust gas flows through the hot fluid channel of the heat exchanger 8 and then enters the dehydration device 10 for dehydration. The dehydrated exhaust gas then enters the cold fluid channel of the heat exchanger 8 for heat absorption and preheating. The preheated exhaust gas is then sent from the cold fluid outlet of the heat exchanger 8 to the circulating fluidized bed reactor 1' for recycling and reaction. The water removed by the dehydration device 10 is pumped by the water pump 12 to the alkaline water electrolysis hydrogen production unit of the hydrogen production subsystem 3, realizing the recycling of water resources. If the gas circulation subsystem includes a dust removal device 9, the high-temperature exhaust gas flows through the hot fluid channel of the heat exchanger 8, first enters the dust removal device 9 to remove dust, and then enters the dehydration device 10 for dehydration. The preheating temperature of the dehydrated hydrogen in the dehydration device 10 is 300-450℃.
[0037] This invention eliminates the need for coking and sintering processes in traditional blast furnace ironmaking, thus achieving "carbon-free metallurgy" with zero carbon dioxide emissions throughout the entire process.
[0038] This invention utilizes iron ore powder, eliminating the sintering process compared to traditional blast furnaces. The circulating fluidized bed exhibits high heat and mass transfer efficiency, long residence time, and high gas-solid reaction rate; therefore, the reduction efficiency of hydrogen for iron ore powder is significantly higher than that of a vertical shaft furnace. Furthermore, this invention employs gas recirculation, fully utilizing the system's heat and simultaneously improving the reduction rate of iron ore in the circulating fluidized bed.
[0039] Circulating fluidized beds (CFBs) are the optimal reactors for gas-solid reactions. Due to the two-phase fluidized state within the reactor, they offer advantages such as high heat and mass transfer efficiency, fast chemical reaction rates, and long residence times, making them widely used in chemical processes, coal combustion, and coal gasification. Achieving the direct reduction reaction of hydrogen with iron ore in a CFB falls under the category of hydrogen metallurgy, completely eliminating carbon dioxide emissions and holding significant importance for achieving carbon neutrality in the steel industry.
[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A circulating fluidized bed hydrogen metallurgical system with microwave heating, characterized in that, It includes a raw material feeding subsystem (7), a hydrogen compressor (4), a pre-reduction fluidized bed reactor (4'), a microwave heating subsystem (5), an electric heating subsystem (6), a circulating fluidized bed reactor (1'), a hydrogen production subsystem (3), an air separation subsystem (1), a nitrogen compressor (2), a gas-solid separation device (2'), a return material device (3'), and a gas circulation subsystem; The discharge end of the raw material feeding subsystem (7) is connected to the feed inlet of the pre-reduction fluidized bed reactor (4'); the gas outlet of the hydrogen production subsystem (3) is connected to the gas inlet of the hydrogen compressor (4); the gas outlet of the air separation subsystem (1) is connected to the gas inlet of the nitrogen compressor (2); and the gas outlets of the hydrogen compressor (4) and the nitrogen compressor (2) merge and are connected to the bottom gas inlet of the pre-reduction fluidized bed reactor (4'). The microwave heating subsystem (5) is arranged around the outside of the pre-reduction fluidized bed reactor (4'); the outlet of the pre-reduction fluidized bed reactor (4') is connected to the feed end of the circulating fluidized bed reactor (1') through a pipe; the electric heating subsystem (6) is arranged around the outside of the riser pipe of the circulating fluidized bed reactor (1'); the outlet of the circulating fluidized bed reactor (1') is connected to the feed end of the gas-solid separation device (2'); the solid phase outlet of the gas-solid separation device (2') is connected to the feed end of the return device (3'); and the outlet of the return device (3') is connected to the feed end of the circulating fluidized bed reactor (1'). The gas circulation subsystem includes a heat exchange device (8) and a dehydration device (10); the gas phase outlet of the gas-solid separation device (2') is connected to the hot fluid inlet of the heat exchange device (8), and the hot fluid outlet of the heat exchange device (8) is connected to the inlet of the dehydration device (10); the gas phase outlet of the dehydration device (10) is connected to the cold fluid inlet of the heat exchange device (8), and the cold fluid outlet of the heat exchange device (8) is connected to the air inlet of the circulating fluidized bed reactor (1'); the liquid phase outlet of the dehydration device (10) is connected to the water inlet of the water pump (12). The outlet of the water pump (12) is connected to the inlet of the hydrogen production subsystem (3).
2. The circulating fluidized bed hydrogen metallurgical system with microwave heating according to claim 1, characterized in that, The microwave heating subsystem (5) includes a microwave heater and is a cavity structure that is wrapped around the outside of the pre-reduction fluidized bed reactor (4').
3. The circulating fluidized bed hydrogen metallurgical system with microwave heating according to claim 1, characterized in that, In the gas circulation subsystem, a dust removal device (9) is connected in series between the heat exchange device (8) and the dehydration device (10). The gas phase discharged from the gas-solid separation device (2') flows sequentially through the hot fluid channel of the heat exchange device (8) and the dust removal device (9) before entering the dehydration device (10).
4. A circulating fluidized bed hydrogen metallurgical system with microwave heating according to claim 1, characterized in that, It also includes a melting pool (11), the feed end of which is connected to the bottom discharge end of the circulating fluidized bed reactor (1') via a pipe; the outlet end of the hydrogen compressor (4) is connected to the feed end of the melting pool (11).
5. A circulating fluidized bed hydrogen metallurgical system with microwave heating according to claim 1, characterized in that, The hydrogen production subsystem (3) consists of a photovoltaic power generation unit and an alkaline water electrolysis hydrogen production unit, with the photovoltaic power generation unit providing electrical energy to the alkaline water electrolysis hydrogen production unit.
6. A hydrogen metallurgical method based on the microwave-heated circulating fluidized bed hydrogen metallurgical system according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Start the hydrogen production subsystem (3), which is powered by its photovoltaic power generation unit and uses the alkaline water electrolysis hydrogen production unit to produce hydrogen; at the same time, start the air separation subsystem (1) to separate nitrogen and start the raw material feeding subsystem (7) to feed iron ore powder into the pre-reduction fluidized bed reactor (4'). S2: Nitrogen separated by the air separation subsystem (1) is introduced into the pre-reduction fluidized bed reactor (4') through the nitrogen compressor (2) to maintain an inert atmosphere in the pre-reduction reactor (4'); then the nitrogen input channel is closed, the hydrogen compressor (4) is turned on, and the hydrogen prepared by the hydrogen production subsystem (3) is introduced into the pre-reduction fluidized bed reactor (4'). At the same time, the microwave heating subsystem (5) is started to pre-treat the iron ore powder in the pre-reduction fluidized bed reactor (4') with microwave heating. S3. After the pretreatment is completed, hydrogen is continued to flow into the pre-reduction fluidized bed reactor (4'). After the iron ore powder in the pre-reduction fluidized bed reactor (4') is initially reduced, it enters the circulating fluidized bed reactor (1') through the discharge port. The electric heating subsystem (6) is started to heat the riser section of the circulating fluidized bed reactor (1'), and the iron ore powder undergoes a reduction reaction in the circulating fluidized bed reactor (1'). The gas-solid mixture after the reaction enters the gas-solid separation device (2') from the discharge end of the circulating fluidized bed reactor (1'). After gas-solid separation, the solid material enters the return device (3') and is sent back to the circulating fluidized bed reactor (1') by the return device (3') to continue the reaction until the iron ore powder is completely reduced. S4. The high-temperature reduction tail gas separated by the gas-solid separation device (2') enters the heat exchange device (8) of the gas circulation subsystem; the high-temperature tail gas flows through the hot fluid channel of the heat exchange device (8) and then enters the dehydration device (10) for dehydration treatment; the dehydrated tail gas enters the cold fluid channel of the heat exchange device (8) for heat absorption and preheating, and the preheated tail gas is sent to the circulating fluidized bed reactor (1') through the cold fluid outlet of the heat exchange device (8) to participate in the reaction; the water removed by the dehydration device (10) is transported to the alkaline electrolysis water production unit of the hydrogen production subsystem (3) through the water pump (12) to realize the recycling of water resources.
7. The circulating fluidized bed hydrogen metallurgical method with microwave heating according to claim 6, characterized in that, In step S2, the microwave frequency of the microwave heating subsystem (5) is 2.45 GHz.
8. The circulating fluidized bed hydrogen metallurgical method with microwave heating according to claim 6, characterized in that, In step S3, the particle size range of the heated iron ore powder is 0-8mm; the temperature of the reduction reaction zone in the circulating fluidized bed reactor (1') is 800-950℃, the temperature difference between different parts of the reduction reaction zone in the circulating fluidized bed reactor (1') is 0-80℃, and the apparent fluidization velocity of the circulating fluidized bed is 4-5m / s.
9. The circulating fluidized bed hydrogen metallurgical method with microwave heating according to claim 6, characterized in that, In step S4, if the gas circulation subsystem includes a dust removal device (9), the high-temperature exhaust gas flows through the hot fluid channel of the heat exchange device (8), first enters the dust removal device (9) to remove dust, and then enters the dehydration device (10) for dehydration treatment; the hydrogen preheating temperature after dehydration by the dehydration device (10) is 300-450℃.
10. The circulating fluidized bed hydrogen metallurgy method with microwave heating according to claim 6, characterized in that, In step S3, the direct reduced iron generated in the circulating fluidized bed reactor (1') is transported to the molten pool (11) through its bottom discharge end; hydrogen is introduced into the molten pool (11) through the hydrogen compressor (4) to form a reducing atmosphere and avoid oxidation of the molten direct reduced iron.