Direct reduction ironmaking system and process method with full hydrogen-based shaft furnace

Abstract

The application provides a full-hydrogen-based shaft furnace direct reduction iron-making system and a process method, and the iron-making system comprises a shaft furnace unit, the shaft furnace unit is provided with a shaft furnace and a gas supply pipe and a heat recovery pipe connected with the shaft furnace, the shaft furnace is sequentially provided with a reduction zone, a constant pressure zone and a cooling zone from top to bottom, the gas supply pipe is connected with the lower part of the cooling zone, and the heat recovery pipe is connected with the constant pressure zone and the upper part of the reduction zone; a gas circulation unit is provided with a process gas circulation pipe connected with the top flue gas outlet of the shaft furnace and the reduction zone, a first dust remover and a dehydrator are arranged on the process gas circulation pipe; and a control unit is connected with the shaft furnace unit and the gas circulation unit. The application can solve the problems of uneven temperature distribution in the furnace and low heat energy utilization rate in the existing full-hydrogen-based shaft furnace process, and realizes the energy cascade utilization in the shaft furnace and the balanced regulation and control of the heat field in the furnace.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology, and in particular to a direct reduction ironmaking system and process method using a fully hydrogen-based vertical shaft furnace. Background Technology

[0002] Direct reduction (DRI) ironmaking in shaft furnaces is a low-carbon and efficient ironmaking process that has been widely adopted globally. This process involves introducing a gaseous reducing agent into the shaft furnace, which then reacts counter-currently with the iron-containing charge moving downwards, reducing it to produce direct reduced iron (DRI), which can be used in electric arc furnace steelmaking. Currently, mainstream gas-based shaft furnace processes primarily use natural gas as the gas source, generating a hydrogen- and carbon monoxide-rich mixed gas through reforming reactions for reduction. Representative processes include MIDREX and HYL-Energiron. These technologies have achieved mature commercialization in regions rich in natural gas resources, offering advantages such as process stability, high product quality, and relatively low carbon emissions.

[0003] However, this type of gas-based shaft furnace process relies on natural gas as a reducing gas source, making it unsuitable for regions with scarce fossil fuel resources. Furthermore, while this process significantly reduces carbon emissions compared to traditional shaft furnace processes, natural gas still contains carbon-based components, inevitably generating carbon dioxide during combustion and reduction, making complete decarbonization difficult.

[0004] With the global steel industry's push towards "dual carbon" goals, pure hydrogen metallurgy, which replaces hydrocarbon gases with hydrogen, has become a key area of ​​research and industrialization. In recent years, some studies have explored the possibility of using pure hydrogen as a reducing agent in direct reduction in vertical shaft furnaces, a system that theoretically can achieve near-zero carbon emissions in ironmaking. However, many engineering challenges remain in the pure hydrogen reduction process, such as uneven heat distribution within the furnace, low utilization efficiency, and high requirements for equipment safety and system integrity.

[0005] In summary, there is an urgent need to develop a direct reduction ironmaking system and process based entirely on hydrogen gas in a vertical shaft furnace, enabling it to have gas recycling capabilities, optimized heat management in different zones, and product cooling functions. This will promote the transformation of hydrogen metallurgy technology from demonstration to engineering implementation, and help the steel industry achieve deep decarbonization and sustainable development. Summary of the Invention

[0006] The purpose of this invention is to provide a direct reduction ironmaking system and process for a hydrogen-based vertical shaft furnace, which solves the problems of uneven temperature distribution and low thermal energy utilization in the existing hydrogen-based vertical shaft furnace process, and realizes the cascade utilization of energy in the vertical shaft furnace and the balanced control of the furnace thermal field.

[0007] The above-mentioned technical objectives of the present invention are mainly achieved through the following technical solutions.

[0008] On one hand, the present invention provides a hydrogen-based vertical shaft furnace direct reduction ironmaking system, which includes: A vertical furnace unit, comprising a vertical furnace, a gas supply pipe and a heat recovery pipe connected to the vertical furnace, wherein the vertical furnace comprises a reduction zone, a constant pressure zone and a cooling zone from top to bottom, the gas supply pipe is connected to the lower part of the cooling zone, and the heat recovery pipe is connected to the upper part of the constant pressure zone and the reduction zone; A gas circulation unit, wherein the gas circulation unit has a process gas circulation pipe connecting the flue gas outlet at the top of the vertical furnace and the reduction zone, and the process gas circulation pipe is equipped with a first dust collector and a dehydrator; The control unit is connected to the vertical furnace unit and the gas circulation unit.

[0009] In a preferred embodiment of the present invention, the all-hydrogen-based vertical shaft furnace direct reduction ironmaking system further includes: A charging unit is located at the top of the vertical furnace to feed iron-containing furnace charge into the furnace. The charging unit has a charging hopper connected to the charging port at the top of the vertical furnace. The control unit is connected to the charging unit.

[0010] In a preferred embodiment of the present invention, the all-hydrogen-based vertical shaft furnace direct reduction ironmaking system further includes: The product processing unit is located at the bottom of the vertical furnace to receive and transport direct reduced iron. The product processing unit has a safety detection device and a direct reduced iron storage and transportation device. The control unit is connected to the product processing unit.

[0011] In a preferred embodiment of the present invention, the reduction zone comprises a preheating reduction zone and a high-temperature reduction zone from top to bottom; The top of the vertical furnace is provided with a flue gas outlet, and the side wall of the vertical furnace is provided with a cooling exhaust gas inlet that connects to the preheating reduction zone, a high temperature reducing gas inlet that connects to the high temperature reduction zone, a cooling exhaust gas outlet that connects to the constant pressure zone, and a low temperature reducing gas inlet that connects to the lower part of the cooling zone. The outlet end of the gas supply pipe is connected to the low-temperature reducing gas inlet, the two ends of the heat recovery pipe are connected to the cooling exhaust gas outlet and the cooling exhaust gas inlet respectively, and the two ends of the process gas circulation pipe are connected to the flue gas outlet and the high-temperature reducing gas inlet respectively.

[0012] In a preferred embodiment of the present invention, a compressor is further provided on the process gas circulation pipe, and the first dust collector, the dehydrator and the compressor are arranged in sequence along the flow direction of the flue gas in the process gas circulation pipe.

[0013] In a preferred embodiment of the present invention, a heat exchanger is provided between the upstream portion of the process gas circulation pipe of the first dust collector and the downstream portion of the process gas circulation pipe of the compressor.

[0014] In a preferred embodiment of the present invention, a heating furnace is provided at one end of the process gas circulation pipe connected to the reduction zone.

[0015] In a preferred embodiment of the present invention, the gas supply pipe is provided with a hydrogen storage tank and a pressure regulator.

[0016] In a preferred embodiment of the present invention, a second dust collector is provided on the heat recovery pipe.

[0017] In a preferred embodiment of the present invention, the regenerating pipe downstream of the second dust collector has a branched parallel section, the branched parallel section having two regenerating branch pipes arranged in parallel, one of which is provided with a heater.

[0018] On the other hand, the present invention also provides a direct reduction ironmaking process using a hydrogen-based vertical shaft furnace, comprising: Iron-containing furnace charge is fed into the upper part of the vertical furnace through the charging hopper, while high-temperature reducing gas is sent into the middle part of the vertical furnace to generate direct reduced iron in the reduction zone. Hydrogen-rich cooling gas is fed into the lower part of the vertical furnace to exchange heat with the direct reduced iron in the cooling zone in a countercurrent manner. After the heat exchange, the hydrogen-rich cooling gas is exported from the constant pressure zone and introduced into the reduction zone to preheat and pre-reduce the iron-containing furnace charge. The flue gas produced by the reaction of the high-temperature reducing gas and the hydrogen-rich cooling gas is discharged from the top outlet of the vertical furnace and subjected to dust removal and dehydration treatment. Then, the flue gas is used as the high-temperature reducing gas and introduced into the middle of the vertical furnace.

[0019] In a preferred embodiment of the present invention, the reduction zone comprises a preheating reduction zone and a high-temperature reduction zone from top to bottom. The hydrogen-rich cooling gas exported from the constant pressure zone is introduced into the preheating reduction zone to preheat and pre-reduce the iron-containing furnace charge. The treated flue gas is introduced into the high-temperature reduction zone to reduce the iron-containing furnace charge.

[0020] In a preferred embodiment of the present invention, the flue gas is pressurized and heated sequentially before being introduced into the vertical furnace as the high-temperature reducing gas.

[0021] In a preferred embodiment of the present invention, the pressurized flue gas is subjected to heat exchange treatment with the flue gas before dust removal treatment.

[0022] In a preferred embodiment of the present invention, the hydrogen-rich cooling gas is pressure-regulated before being introduced into the cooling zone of the vertical furnace.

[0023] In a preferred embodiment of the present invention, the hydrogen-rich cooling gas is subjected to dust removal treatment before being introduced into the reduction zone of the vertical furnace after heat exchange and heating.

[0024] In a preferred embodiment of the present invention, the hydrogen-rich cooling gas is heated before being sent into the reduction zone after dust removal.

[0025] Compared with the prior art, the technical solution of the present invention has the following characteristics and advantages: This invention establishes an integrated process of "continuous raw material supply, high-temperature reduction, countercurrent cooling, closed-loop gas circulation, and safe product handling" by constructing a vertical shaft furnace direct reduction ironmaking system and process using pure hydrogen as a reducing agent.

[0026] First, the present invention sets up a cooling zone inside the vertical furnace, and uses pure hydrogen gas introduced from the bottom of the furnace to exchange heat with the high-temperature direct reduction iron in a countercurrent manner, so that the metallized pellets are rapidly cooled to a safe temperature in the furnace before being discharged. It is equipped with dust concentration, gas composition and temperature monitoring devices, as well as an inert gas protection system, to build a safe material discharge and storage and transportation system throughout the entire process, effectively ensuring the safety of the product processing.

[0027] Secondly, this invention constructs a highly efficient closed-loop gas circulation and heat recovery system. The process gas from the furnace top is repeatedly heated and reused after heat exchange, dust removal, dehydration, and pressurization. Combined with the cooling exhaust gas, it is drawn upward to the upper part of the vertical furnace, realizing the cascade utilization of energy and the upward balanced control of the internal thermal field.

[0028] In summary, this invention not only has significant advantages in terms of process stability, energy efficiency, and system safety, but also possesses great potential for industrial application and promotional value. Attached Figure Description

[0029] 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0030] Figure 1 This is a process flow diagram of the all-hydrogen-based vertical shaft furnace direct reduction ironmaking system described in this invention; Figure 2 This is a schematic diagram of the structure of the all-hydrogen-based vertical shaft furnace direct reduction ironmaking system described in this invention.

[0031] Explanation of reference numerals in the attached figures: 10. Vertical shaft furnace; 11. Flue gas outlet; 12. Cooling exhaust gas inlet; 13. High-temperature reducing gas inlet; 14. Cooling exhaust gas outlet; 15. Low-temperature reducing gas inlet; 16. Charging port; 17. Discharge port; 20. Gas supply pipe; 21. Hydrogen storage tank; 22. Pressure regulator; 30. Heat recovery pipe; 31. Second dust collector; 32. Heater; 40. Process gas circulation pipe; 41. Heat exchanger; 42. First dust collector; 43. Dehydrator; 44. Pressurizer; 45. Heating furnace; 50. Feeding unit. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0033] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] Implementation Method 1: This invention provides a hydrogen-based vertical shaft furnace direct reduction ironmaking system, such as... Figure 1 and Figure 2 As shown, it includes: a vertical furnace unit, which has a vertical furnace 10, and a gas supply pipe 20 and a regenerating pipe 30 connected to the vertical furnace 10. The vertical furnace 10 has a reduction zone, a constant pressure zone and a cooling zone from top to bottom. The gas supply pipe 20 is connected to the lower part of the cooling zone, and the regenerating pipe 30 is connected to the upper part of the constant pressure zone and the reduction zone; a gas circulation unit, which has a process gas circulation pipe 40 connecting the flue gas outlet 11 at the top of the vertical furnace 10 and the reduction zone. The process gas circulation pipe 40 is equipped with a first dust collector 42 and a dehydrator 43; and a control unit, which is connected to the vertical furnace unit and the gas circulation unit.

[0036] The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system of this invention constructs a highly efficient gas closed-loop circulation and heat recovery system; the flue gas at the furnace top is treated by dust removal and dehydration and then reintroduced into the reduction zone as high-temperature reducing gas, realizing the circulation of flue gas and high-temperature reducing gas; at the same time, the cooling gas in the gas supply pipe 20 is used to cool the direct reduced iron in the cooling zone, and then the heated cooling gas is introduced into the reduction zone for preheating and pre-reduction of the furnace charge, realizing the cascade utilization of energy and the upward balanced control of the furnace internal thermal field.

[0037] The following section will provide a detailed description of the specific structure of each part of the all-hydrogen-based vertical shaft furnace direct reduction ironmaking system described in this invention, as well as the positional relationships and pipeline connections between each part.

[0038] The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system of the present invention has a vertical shaft furnace unit, such as... Figure 1 and Figure 2 As shown, the vertical furnace unit is the core part of the present invention. The vertical furnace unit has a vertical furnace 10, and a gas supply pipe 20 and a heat recovery pipe 30 connected to the vertical furnace 10.

[0039] like Figure 2As shown, the vertical shaft furnace 10 adopts a vertical structure design. From top to bottom, the furnace consists of a reduction zone, a constant pressure zone, and a cooling zone, used to complete the gas-solid reduction reaction of oxidized pellets (containing iron charge), and the cooling and discharge of direct reduced iron (DRI) products. In the reduction zone, the oxidized pellets react with the reducing agent (hydrogen) to produce elemental iron (direct reduced iron). In the cooling zone, the DRI produced by the reaction can be cooled in various ways to prevent it from re-oxidizing after being tapped from the furnace. The inner wall of the vertical shaft furnace 10 is constructed with refractory materials to withstand the high-temperature reaction environment and provide insulation; the outer shell is a steel structure to provide sufficient mechanical strength.

[0040] like Figure 2 As shown, a low-temperature reducing gas inlet 15, connecting to the lower part of the cooling zone, is provided on the side wall of the vertical furnace 10. The outlet end of the gas supply pipe 20 is connected to the low-temperature reducing gas inlet 15, used to introduce low-temperature reducing gas (usually low-temperature hydrogen-rich reducing gas, i.e., hydrogen-rich cooling gas as described below) into the cooling zone. The low-temperature reducing gas entering the cooling zone can cool the direct reduced iron generated above, thereby reducing the temperature of the direct reduced iron. The hydrogen-rich reducing gas (hydrogen-rich cooling gas) uses room-temperature hydrogen with a purity of 99.9%.

[0041] like Figure 2 As shown, the side wall of the vertical furnace 10 has a cooling exhaust gas outlet 14 connecting to the constant pressure zone and a cooling exhaust gas inlet 12 connecting to the reduction zone; the inlet and outlet ends of the regenerator pipe 30 are connected to the cooling exhaust gas outlet 14 and the cooling exhaust gas inlet 12, respectively. The cooling exhaust gas (heated hydrogen-rich reducing gas) generated after heat exchange and heating in the cooling zone enters the constant pressure zone and can be discharged from the cooling exhaust gas outlet 14 into the vertical furnace 10 and into the regenerator pipe 30. Then, it re-enters the vertical furnace 10 through the cooling exhaust gas inlet 12 and comes into contact with the falling iron-containing furnace charge in the upper reduction zone to preheat and pre-reduce the iron-containing furnace charge. After that, it is discharged from the top of the furnace, thereby realizing the recovery and utilization of heat.

[0042] The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system of the present invention also has a gas circulation unit for treating the flue gas generated by the vertical shaft furnace 10 to achieve recycling of the flue gas as process gas, such as... Figure 1 and Figure 2 As shown, the process gas circulation treatment unit mainly has a process gas circulation pipe 40 connected to the vertical furnace 10.

[0043] like Figure 2As shown, the top of the vertical shaft furnace 10 has a flue gas outlet 11, and the side wall of the vertical shaft furnace 10 has a high-temperature reducing gas inlet 13 that connects to the reduction zone; the inlet and outlet ends of the process gas circulation pipe 40 are connected to the flue gas outlet 11 and the high-temperature reducing gas inlet 13, respectively. The flue gas generated after the reduction reaction occurs in the reduction zone of the vertical shaft furnace 10 can enter the process gas circulation pipe 40 through the flue gas outlet 11. The source of the flue gas is the cooling tail gas entering the reduction zone from the cooling tail gas inlet 12, and the high-temperature reducing gas entering the reduction zone from the high-temperature reducing gas inlet 13.

[0044] like Figure 2 As shown, the process gas circulation pipe 40 is equipped with a first dust collector 42 and a dehydrator 43. The first dust collector 42 uses wet dust removal to remove dust particles and some water vapor from the flue gas; the dehydrator 43 is used to remove liquid water from the flue gas. The purified flue gas, as high-temperature reducing gas, re-enters the reduction zone of the vertical furnace 10 through the high-temperature reducing gas inlet 13, realizing a closed-loop circulation of high-temperature reducing gas and flue gas. During the circulation process, the cooling tail gas entering through the cooling tail gas inlet 12 continuously replenishes the hydrogen content in the circulating gas. The main component of the high-temperature reducing gas produced after flue gas treatment is hydrogen, and its temperature needs to reach the reaction temperature required by the reduction zone in the vertical furnace 10, which is usually around 1000℃.

[0045] The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system described in this invention also has a control unit, such as... Figure 1 and Figure 2 As shown, the control unit is used for unified management of the system's process, and to monitor and adjust key parameters such as raw material supply, gas composition, temperature distribution, and furnace pressure in real time to ensure stable system operation and efficient and controllable reaction process.

[0046] The control unit consists of a control cabinet, a sensor network, and actuators. The control cabinet integrates advanced process control algorithms to achieve automated control of the entire system. The sensor network monitors key parameters such as temperature, pressure, flow rate, and gas composition in real time, while the actuators adjust the operating status of each device according to control commands. This control unit has functions such as parameter optimization, fault diagnosis, and safety interlocking.

[0047] This invention achieves the organic synergy of efficient gas utilization, stable reduction reaction, and stepwise heat recovery, resulting in a metallization rate of over 92% for direct reduced iron products. The functions of each unit are clearly defined and closely integrated, constructing a fully hydrogen-based vertical shaft furnace direct reduction ironmaking system with high metallization rate, high energy efficiency, and high safety, demonstrating excellent industrial adaptability and promising prospects for widespread application.

[0048] The following will further explain the structure and technical effects of the preferred embodiment of the all-hydrogen-based vertical shaft furnace direct reduction ironmaking system described in this invention.

[0049] According to one embodiment of the present invention, such as Figure 1 and Figure 2 As shown, the all-hydrogen-based vertical shaft furnace direct reduction ironmaking system also includes a charging unit 50, which is located at the top of the vertical shaft furnace 10 to feed iron-containing furnace charge into the vertical shaft furnace 10. The charging unit 50 has a charging hopper connected to the charging port 16 at the top of the vertical shaft furnace 10, and the control unit is connected to the charging unit 50.

[0050] The charging unit 50 consists of a charging hopper, a raw material pretreatment device, and a feeding device. The charging hopper is used to store iron-containing furnace materials (such as oxide pellets); the raw material pretreatment device performs necessary pretreatment on the iron-containing furnace materials, such as screening and drying, to ensure that the quality of the raw materials meets the requirements of the reduction process; the feeding device is responsible for quantitatively feeding the raw materials into the vertical furnace 10.

[0051] During raw material storage, transportation, and feeding, high-purity hydrogen is used for pressure equalization in the feeding hopper and equipment purging to prevent other gases from contaminating the hydrogen purity of the system, thereby ensuring the stability of the reducing atmosphere and reaction efficiency. The feeding unit 50 ensures the continuity and stability of raw material supply.

[0052] The entire feeding process is managed by a control unit to ensure stable system operation and efficient and controllable reaction process.

[0053] According to one embodiment of the present invention, such as Figure 1 As shown, the all-hydrogen-based vertical shaft furnace direct reduction ironmaking system also includes a product processing unit, which is located at the bottom of the vertical shaft furnace 10 and connected to the discharge port 17 to receive and transport direct reduced iron. The product processing unit has a safety detection device and a direct reduced iron storage and transportation device, and the control unit is connected to the product processing unit.

[0054] The product handling unit consists of a series of safety detection devices and direct reduced iron (DRI) storage and transportation equipment to ensure the safety of DRI storage and transportation. The safety detection devices include inert gas protection devices, dust concentration detection devices, gas concentration detection devices, and temperature detection devices. The DRI storage and transportation equipment includes transport equipment, DRI buffer silos, DRI powder silos, and DRI silos.

[0055] According to one embodiment of the present invention, such as Figure 2 As shown, the reduction zone consists of a preheating reduction zone and a high-temperature reduction zone from top to bottom; the cooling exhaust gas inlet 12 on the side wall of the vertical furnace 10 is connected to the preheating reduction zone, and the high-temperature reducing gas inlet 13 on the side wall of the vertical furnace 10 is connected to the high-temperature reduction zone.

[0056] Since the heat generated by the cooling exhaust gas after heat exchange in the cooling zone is slightly less than the heat of the high-temperature reducing gas introduced into the high-temperature reduction zone, it is introduced into the preheating reduction zone for preheating and pre-reduction to ensure the high-temperature environment in the high-temperature reduction zone and to ensure the efficient reduction reaction and product quality of the iron-containing furnace charge in the high-temperature reduction zone.

[0057] According to one embodiment of the present invention, such as Figure 2 As shown, a compressor 44 is also provided on the process gas circulation pipe 40. Along the flow direction of the flue gas in the process gas circulation pipe 40, the first dust collector 42, the dewatering device 43 and the compressor 44 are arranged in sequence.

[0058] The first dust collector 42 is placed before the dehydrator 43 and the pressurizer 44 to prevent dust in the flue gas from damaging the dehydrator 43 and the pressurizer 44. The flue gas after dust removal and dehydration is pressurized by the pressurizer 44 to increase the pressure of the flue gas to 0.3MPa~0.7MPa, so as to keep it in balance with the gas pressure in the vertical furnace 10 and avoid significant pressure fluctuations in the vertical furnace 10 due to the introduction of flue gas, so as to meet the gas pressure and flow requirements of the reduction reaction in the vertical furnace 10.

[0059] According to one embodiment of the present invention, such as Figure 2 As shown, a heat exchanger 41 is provided between a portion of the process gas circulation pipe 40 upstream of the first dust collector 42 and a portion of the process gas circulation pipe 40 downstream of the compressor 44.

[0060] The flue gas before dust removal and dehydration and the pressurized flue gas in the process gas circulation pipe 40 are subjected to heat exchange treatment. The flue gas before dust removal and dehydration has a high temperature, and its temperature decreases after passing through the heat exchanger 41, which facilitates the subsequent dust removal and dehydration processes. At the same time, the pressurized flue gas is reintroduced into the heat exchanger 41, so that heat is transferred back into the flue gas. The flue gas is cooled down and then heated up again, ensuring that the gas introduced into the high-temperature reduction zone has a high temperature and avoiding temperature fluctuations in the vertical furnace 10.

[0061] According to one embodiment of the present invention, such as Figure 2 As shown, a heating furnace 45 is provided at one end of the process gas circulation pipe 40 that is connected to the reduction zone.

[0062] The heating furnace 45 heats the pressurized flue gas to a set high temperature (950℃-1050℃) to ensure that the reducing gas entering the upper part of the vertical furnace 10 has a stable temperature and reactivity, thereby improving the reduction efficiency and production stability.

[0063] According to one embodiment of the present invention, such as Figure 2 As shown, the gas supply pipe 20 is equipped with a hydrogen storage tank 21 and a pressure regulator 22.

[0064] The hydrogen storage tank 21 contains room temperature hydrogen (about 25°C). The room temperature hydrogen is sent to the lower part of the cooling zone of the vertical furnace 10 after passing through the pressure regulator 22 as a low temperature reducing gas (cooling gas). It comes into countercurrent contact with the downward high temperature direct reduced iron to complete the cooling process.

[0065] According to one embodiment of the present invention, such as Figure 2 As shown, a second dust collector 31 is installed on the regenerator pipe 30. The cooling exhaust gas generated after heat exchange with the direct reduced iron in the cooling zone is treated to remove dust before being introduced into the preheating reduction zone, thereby avoiding pipe blockage and reducing impurities in the material.

[0066] According to one embodiment of the present invention, such as Figure 2 As shown, the regenerating pipe 30 downstream of the second dust collector 31 has a branch parallel section, which has two regenerating branch pipes arranged in parallel, one of which is equipped with a heater 32.

[0067] If the temperature of the high-temperature reducing gas entering the furnace is limited, or if the effective height of the high-temperature reduction zone is reduced due to furnace condition fluctuations, the heater 32 is started. Part of the cooling exhaust gas in the heat recovery pipe 30 can be quickly heated to the target temperature through the heater 32 and sent into the reduction zone for supplemental heating, thereby ensuring the residence time of the oxide pellets in the reduction zone and the metallization rate of the product, making reasonable use of resources and reducing energy consumption.

[0068] Implementation Method Two: This invention also provides a direct reduction ironmaking process using a hydrogen-based vertical shaft furnace, comprising the following steps: Step S1: The iron-containing furnace charge is fed into the upper part of the vertical furnace 10 through the charging hopper, and at the same time, high-temperature reducing gas is sent into the middle part of the vertical furnace 10 to generate direct reduced iron in the reduction zone. Step S2: The hydrogen-rich cooling gas is fed into the lower part of the vertical furnace 10 to exchange heat with the direct reduced iron in the cooling zone in a countercurrent manner. After the heat exchange, the hydrogen-rich cooling gas is discharged from the constant pressure zone and introduced into the reduction zone to preheat and pre-reduce the iron-containing furnace charge. Step S3: The flue gas generated after the reaction of high-temperature reducing gas and hydrogen-rich cooling gas is discharged from the top outlet of the vertical furnace 10 and subjected to dust removal and dehydration treatment. Then, the flue gas is introduced into the middle of the vertical furnace 10 as high-temperature reducing gas.

[0069] It should be noted that the above steps are described in sequence according to the process of the iron-containing furnace charge falling in the vertical furnace 10. In actual production, the ironmaking process in the vertical furnace 10 is a continuous process, and the above steps are all carried out simultaneously.

[0070] The hydrogen-based vertical shaft furnace direct reduction ironmaking process described in this invention employs a dual-path feeding of process gas into the vertical shaft furnace 10. On one hand, the flue gas generated at the furnace top is purified and then enters the reduction zone of the vertical shaft furnace 10 as high-temperature reducing gas, providing the main heat and reducing atmosphere. On the other hand, the hydrogen-rich cooling gas, which serves as cooling gas, enters from the furnace bottom to cool the direct reduced iron and then flows back to the upper part of the furnace body to participate in the pellet preheating process again. This achieves the cascade utilization of sensible heat and effectively reduces the total energy consumption of the process.

[0071] The following section will provide a detailed description of the specific process steps of the direct reduction ironmaking process using a hydrogen-based vertical shaft furnace as described in this invention.

[0072] In step S1, the feeding and reduction processes are carried out.

[0073] The selected material has an Fe content of 67%~69%, a particle size of 8~16mm, and a bulk density of 2.1t / m³. 3 High-grade oxidized pellets are used as furnace charge. The charge is continuously fed into the vertical furnace 10 from the top via a feeding device, and moves downwards under gravity, gradually entering each functional zone to participate in the reaction. During the charge transportation and storage process, high-purity hydrogen is used for pressure equalization and equipment purging to avoid other gases from mixing in and affecting the hydrogen purity of the system, thereby ensuring the stability of the reducing atmosphere and the reaction efficiency.

[0074] High-temperature reducing gas enters the middle of the vertical furnace 10 through high-temperature reducing gas inlet 13, maintaining a stable atmosphere and temperature field in the reduction zone and providing the necessary heat and reducing agent for the reduction of the furnace charge. The iron-containing furnace charge forms a continuous column of charge falling from top to bottom, and undergoes a reduction reaction with the high-temperature reducing gas in the reduction zone to generate high-temperature direct reduced iron.

[0075] In step S2, a cooling and waste heat recovery and reuse process is carried out.

[0076] 99.9% pure room-temperature hydrogen is used as the hydrogen-rich cooling gas. The hydrogen-rich cooling gas enters the cooling zone from the bottom of the vertical furnace 10 and comes into countercurrent contact with the high-temperature direct reduced iron that has been reduced in the lower part of the furnace 10, absorbing its sensible heat to achieve product cooling and gas heating. The cooled direct reduced iron is discharged from the bottom of the vertical furnace 10 and sent to the storage and transportation system.

[0077] After being heated, the hydrogen-rich cooling gas (cooling tail gas) is discharged from the constant pressure zone and sent to the upper part of the reduction zone to mix with the high-temperature reducing gas, thereby preheating and pre-reducing the oxidized pellets and realizing the cascade utilization of sensible heat.

[0078] In step S3, the purification and circulation process of the flue gas from the furnace top is carried out.

[0079] The high-temperature reducing gas and cooling tail gas after the reaction mix in the vertical shaft furnace 10 and converge at the top to form top flue gas. The top flue gas is a mixture containing water vapor, dust, and some unreacted hydrogen. After the gas passes through a wet dust collector to remove water vapor and dust, and a dehydrator to remove liquid water, it is reintroduced into the reduction zone of the vertical shaft furnace 10 as high-temperature reducing gas, thus achieving a closed-loop circulation of high-temperature reducing gas and flue gas.

[0080] The cooled direct reduced iron (DRI) is continuously discharged from the bottom of the vertical shaft furnace 10, first entering the DRI buffer silo, and then, after screening, being sent to the DRI powder silo and DRI cylinder silo for storage. During the discharge process, a safety detection device monitors the dust concentration, hydrogen concentration, oxygen concentration, and temperature in real time. Once an abnormal signal is detected, the system will automatically activate the inert gas protection device, replacing the atmosphere in each silo with inert gas to prevent oxidation or spontaneous combustion of the DRI, ensuring the safety of product storage and transportation.

[0081] The following will provide a detailed description of the preferred embodiment of the all-hydrogen-based vertical shaft furnace direct reduction ironmaking process of the present invention.

[0082] According to one embodiment of the present invention, the reduction zone has a preheating reduction zone and a high-temperature reduction zone from top to bottom. The hydrogen-rich cooling gas exported from the constant pressure zone is introduced into the preheating reduction zone to preheat and pre-reduce the iron-containing furnace charge, and the treated flue gas is introduced into the high-temperature reduction zone to reduce the iron-containing furnace charge.

[0083] Since the heat generated by the cooling exhaust gas after heat exchange in the cooling zone is slightly less than the heat of the high-temperature reducing gas introduced into the high-temperature reduction zone, it is introduced into the preheating reduction zone for preheating and pre-reduction to ensure the high-temperature environment in the high-temperature reduction zone and to ensure the efficient reduction reaction and product quality of the iron-containing furnace charge in the high-temperature reduction zone.

[0084] According to one embodiment of the present invention, before the treated flue gas is introduced into the vertical furnace 10 as a high-temperature reducing gas, the flue gas is pressurized and heated successively.

[0085] The purified flue gas is pressurized to meet the gas pressure and flow requirements of the reduction reaction in the vertical shaft furnace 10; the pressurized hydrogen is heated to a set high temperature to ensure that the high-temperature reducing gas entering the high-temperature reduction zone of the vertical shaft furnace 10 has a stable temperature and reactivity, thereby improving the reduction efficiency and production stability.

[0086] According to one embodiment of the present invention, the pressurized flue gas is subjected to heat exchange treatment with the flue gas before dust removal treatment.

[0087] The flue gas before dust removal and dehydration and the flue gas after pressurization are subjected to heat exchange treatment. The flue gas before dust removal and dehydration has a higher temperature and the flue gas after pressurization has a lower temperature. After heat exchange, the cooled flue gas is easier to process in subsequent dust removal and dehydration processes. The heated flue gas is introduced into the high-temperature reduction zone to maintain a high temperature in the high-temperature reduction zone.

[0088] According to one embodiment of the present invention, the hydrogen-rich cooling gas is pressure-regulated before being introduced into the cooling zone of the vertical furnace 10. The pressure of the hydrogen-rich cooling gas after pressure regulation is kept consistent with the pressure inside the vertical furnace 10, thus avoiding significant pressure fluctuations inside the vertical furnace 10 caused by the introduction of the hydrogen-rich cooling gas.

[0089] According to one embodiment of the present invention, the hydrogen-rich cooling gas is subjected to dust removal treatment before being introduced into the reduction zone of the vertical furnace 10 after heat exchange and heating.

[0090] The cooling exhaust gas (hydrogen-rich cooling gas after heat exchange and heating) generated after contacting and exchanging heat with direct reduced iron in the cooling zone is treated with dust removal before being introduced into the preheating reduction zone, thereby avoiding pipe blockage and reducing impurities in the material.

[0091] According to one embodiment of the present invention, the hydrogen-rich cooling gas is heated before being sent into the reduction zone after dust removal.

[0092] If the effective height of the high-temperature reduction zone is reduced due to factors such as limited temperature of the high-temperature reducing gas entering the furnace or fluctuations in furnace conditions, some of the cooling exhaust gas is heated to the target temperature and sent into the reduction zone for reheating. This ensures the residence time of the oxidized pellets in the reduction zone and the metallization rate of the product, making reasonable use of resources and reducing energy consumption.

[0093] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hydrogen-based vertical shaft furnace direct reduction ironmaking system, characterized in that, include: A vertical furnace unit, the vertical furnace unit having a vertical furnace (10), and a gas supply pipe (20) and a heat recovery pipe (30) connected to the vertical furnace (10), the vertical furnace (10) having a reduction zone, a constant pressure zone and a cooling zone from top to bottom, the gas supply pipe (20) being connected to the lower part of the cooling zone, and the heat recovery pipe (30) being connected to the constant pressure zone and the upper part of the reduction zone; A gas circulation unit has a process gas circulation pipe (40) connecting the flue gas outlet (11) at the top of the vertical furnace (10) and the reduction zone. The process gas circulation pipe (40) is equipped with a first dust collector (42) and a dehydrator (43). The control unit is connected to the vertical furnace unit and the gas circulation unit.

2. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system according to claim 1, characterized in that, Also includes: The feeding unit (50) is located at the top of the vertical furnace (10) to feed iron-containing furnace charge into the vertical furnace (10). The feeding unit (50) has a feeding hopper connected to the feeding port (16) at the top of the vertical furnace (10). The control unit is connected to the feeding unit (50).

3. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system according to claim 1 or 2, characterized in that, Also includes: The product processing unit is located at the bottom of the vertical furnace (10) to receive and transport direct reduced iron. The product processing unit has a safety detection device and a direct reduced iron storage and transportation device. The control unit is connected to the product processing unit.

4. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system according to claim 1, characterized in that, The reduction zone consists of a preheating reduction zone and a high-temperature reduction zone from top to bottom; The top of the vertical furnace (10) is provided with a flue gas outlet (11), and the side wall of the vertical furnace (10) is provided with a cooling exhaust gas inlet (12) that connects to the preheating reduction zone, a high temperature reducing gas inlet (13) that connects to the high temperature reduction zone, a cooling exhaust gas outlet (14) that connects to the constant pressure zone, and a low temperature reducing gas inlet (15) that connects to the lower part of the cooling zone. The outlet end of the gas supply pipe (20) is connected to the low-temperature reducing gas inlet (15), the two ends of the heat recovery pipe (30) are connected to the cooling exhaust gas outlet (14) and the cooling exhaust gas inlet (12) respectively, and the two ends of the process gas circulation pipe (40) are connected to the flue gas outlet (11) and the high-temperature reducing gas inlet (13) respectively.

5. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system according to claim 1 or 4, characterized in that, A compressor (44) is also provided on the process gas circulation pipe (40). The first dust collector (42), the dehydrator (43) and the compressor (44) are arranged in sequence along the flow direction of the flue gas in the process gas circulation pipe (40).

6. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system according to claim 5, characterized in that, A heat exchanger (41) is provided between the upstream portion of the process gas circulation pipe (40) of the first dust collector (42) and the downstream portion of the process gas circulation pipe (40) of the compressor (44).

7. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system according to claim 6, characterized in that, A heating furnace (45) is provided at one end of the process gas circulation pipe (40) that is connected to the reduction zone.

8. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system according to claim 1 or 4, characterized in that, The gas supply pipe (20) is equipped with a hydrogen storage tank (21) and a pressure regulator (22).

9. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system according to claim 1 or 4, characterized in that, The heat recovery pipe (30) is equipped with a second dust collector (31).

10. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking system according to claim 9, characterized in that, The regenerating pipe (30) downstream of the second dust collector (31) has a branch parallel section, which has two regenerating branch pipes arranged in parallel, one of which is equipped with a heater (32).

11. A direct reduction ironmaking process using a hydrogen-based vertical shaft furnace, characterized in that, include: Iron-containing furnace charge is fed into the upper part of the vertical furnace (10) through the charging hopper, and high-temperature reducing gas is sent into the middle part of the vertical furnace (10) to generate direct reduced iron in the reduction zone. Hydrogen-rich cooling gas is fed into the lower part of the vertical furnace (10) to exchange heat with the direct reduced iron in the cooling zone in a countercurrent manner. After the heat exchange, the hydrogen-rich cooling gas is discharged from the constant pressure zone and introduced into the reduction zone to preheat and pre-reduce the iron-containing furnace charge. The flue gas generated after the reaction of the high-temperature reducing gas and the hydrogen-rich cooling gas is discharged from the top outlet of the vertical furnace (10) and subjected to dust removal and dehydration treatment. Then, the flue gas is introduced into the middle of the vertical furnace (10) as the high-temperature reducing gas.

12. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking process according to claim 11, characterized in that, The reduction zone consists of a preheating reduction zone and a high-temperature reduction zone from top to bottom. The hydrogen-rich cooling gas exported from the constant pressure zone is introduced into the preheating reduction zone to preheat and pre-reduce the iron-containing furnace charge. The treated flue gas is introduced into the high-temperature reduction zone to reduce the iron-containing furnace charge.

13. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking process according to claim 11 or 12, characterized in that, Before the treated flue gas is introduced into the vertical furnace (10) as the high-temperature reducing gas, the flue gas is pressurized and heated successively.

14. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking process according to claim 13, characterized in that, The pressurized flue gas is subjected to heat exchange treatment with the flue gas before dust removal treatment.

15. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking process according to claim 11 or 12, characterized in that, Before the hydrogen-rich cooling gas is introduced into the cooling zone of the vertical furnace (10), the hydrogen-rich cooling gas is subjected to pressure regulation.

16. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking process according to claim 11 or 12, characterized in that, Before the hydrogen-rich cooling gas, after heat exchange and heating, is introduced into the reduction zone of the vertical furnace (10), the hydrogen-rich cooling gas is subjected to dust removal treatment.

17. The all-hydrogen-based vertical shaft furnace direct reduction ironmaking process according to claim 16, characterized in that, Before the hydrogen-rich cooling gas after dust removal is sent into the reduction zone, the hydrogen-rich cooling gas is heated.

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