Atmosphere-adjustable gas-based direct reduction ironmaking process

Abstract

To provide a gas-based direct reduction ironmaking system and method having advantages such as diversification, low cost, low energy consumption, low emission, atmosphere adjustable, stable and efficient, and environmental friendliness.SOLUTION: An atmosphere-adjustable gas-based direct reduction ironmaking system includes a shaft furnace, a primary cooling device, a filtration device, a secondary cooling device, a pressurizing device, a combustion gas mixing device, a reduction gas mixing device, a preheating furnace, and a reforming furnace. The combustion gas mixing device and the reduction gas mixing device are respectively provided with a plurality of gas inlet passages. A top gas outlet of the shaft furnace is connected by a conduit to one gas inlet passage of each of the combustion gas mixing device and the reduction gas mixing device through the primary cooling device, the filtration device, the secondary cooling device, and the pressurizing device in sequence. A gas outlet passage of the reducing gas mixing device is connected to the gas inlet of the shaft furnace by a pipe line through the preheating furnace and the reforming furnace in sequence. A gas outlet passage of the combustion gas mixing device is connected to a burner of the reforming furnace by a pipe line.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an adjustable atmosphere gas-based direct reduction iron making system and method, which belongs to the technical field of iron and steel smelting. [Background technology]

[0002] The steel industry is facing enormous pressure to reduce CO2 emissions, and the development of a new generation of green, low-carbon metallurgical technologies has become an unavoidable path for steel enterprises to achieve sustainable development.

[0003] One approach to reducing CO2 emissions is to improve energy utilization efficiency, while the other is to seek clean energy alternatives. Research into the former focuses primarily on highly efficient energy recovery and utilization and breaking through the chemical limitations of low primary energy utilization rates in reactors. With regard to energy alternatives, hydrogen energy is currently the most promising. Hydrogen reduction has the advantages of a fast reaction rate and no pollution from the products, making it an effective way to reduce CO2 emissions. Gas-based direct reduction (a direct reduction steelmaking process in which iron ore is reduced using gas as a reducing agent) is currently the mainstream of hydrogen reduction.

[0004] Currently, hydrogen metallurgy primarily involves reducing iron ore in a gas-fired shaft furnace using a mixture of hydrogen and CO to produce direct reduced iron (DRI), which is then used as feedstock for the subsequent process of arc furnace steelmaking. In recent years, DRI production has continued to increase due to market demand and the implementation of green low-carbon initiatives. Internationally, hydrogen direct reduction projects include the Swedish HYBRIT and MIDREX H2. Advanced steelmaking countries around the world are accelerating their low-carbon metallurgy strategies, with hydrogen metallurgy as a breakthrough. With the implementation of the "carbon peak-out and carbon neutral" strategy, direct reduction has become one of the most important applications of hydrogen metallurgy. Therefore, while building on existing processes and production practices, the development of process technologies and equipment continues, and the development of diversified, low-cost, low-energy, low-emission, stable, highly efficient, and environmentally friendly hydrogen metallurgy refining technologies is a future trend.

[0005] The following briefly describes some prior art related to the technical solution of the present invention.

[0006] Prior art 1 related to the present invention: Technical proposal of Prior Art 1: The reducing gas used in the MIDREX process is obtained by catalytic cracking of natural gas, with furnace gas used as the cracking agent. The furnace gas contains approximately 70% CO and H2, and is pressurized before being introduced into a mixing chamber where it is uniformly mixed with an equivalent amount of natural gas. The resulting mixed gas first enters a heat exchanger that uses the reformer exhaust gas as its heat source and is preheated. The preheated mixed gas is then sent to a group of nickel-based catalytic reaction tubes in the reformer, where it undergoes a catalytic cracking reaction and is reformed into reducing gas. The total CO and H2 content in the reducing gas is approximately 95%, and the temperature is 850-900°C.

[0007] The remaining furnace gas is mixed with an appropriate amount of natural gas as fuel in a mixing chamber and then supplied to the combustion space outside the reaction tubes of the reformer. In addition, the combustion promotion air is also preheated in a heat exchanger to increase the combustion temperature.

[0008] The reformer combustion exhaust gas contains less than 1% O2. The high-temperature exhaust gas is first sent to a heat exchanger, where it preheats the combustion-promoting air and the mixed feed gas in sequence. A portion of the exhaust gas discharged from the heat exchanger is cleaned, pressurized, and supplied as seal gas to the gas seal devices at the top and bottom of the furnace, while the remainder is discharged into the atmosphere by a smoke exhauster.

[0009] Disadvantages of Prior Art 1: The MIDREX process is only suitable for natural gas, which limits the type of gas source and the gas ratio. Meanwhile, the MIDREX process uses wet dust collection, resulting in poor dust purification efficiency and a complex water treatment system. The pipes and equipment used in the wet dust collector are prone to corrosion, resulting in defective products and hindering the recovery and reuse of by-products. Sludge discharged from the dust collector can also cause secondary pollution. Furthermore, because the process consumes a certain amount of water, care must be taken to prevent freezing in cold regions; if the equipment is installed outdoors, it may freeze in winter.

[0010] Prior art 2 related to the present invention: Technical proposal of Prior Art 2: The basic principle of the HYL process is the reduction of iron ore with reducing gas in a fixed bed. The reducing gas hydrocarbons (natural gas or coke oven gas) used are produced by incomplete combustion and reforming in the furnace through the catalytic action of metallic iron in the reduction reactor. The process flow is characterized by incomplete combustion of the reducing gas, gas reforming at the bottom of the reduction zone of the reactor, and adjustable reaction gas composition. The HYL-ZR technology, a gas self-reforming technology developed by Mexico's HYL, allows the HYL process to directly use gas produced from coal using oxygen / steam as an oxidant.

[0011] Disadvantages of Prior Art 2: On the other hand, the HYL process obtains reduced gas through wet reforming of natural gas and steam. However, the use of gas self-reforming technology results in a low ratio of active ingredients in the reduced gas, resulting in poor reduction efficiency. Meanwhile, the HYL process employs wet dust collection, resulting in poor dust purification. The piping and equipment used in the wet dust collector are prone to corrosion, resulting in defective products and hindering the recovery and reuse of by-products. Sludge discharged from the dust collector can also cause secondary pollution. Furthermore, because the process consumes a certain amount of water, care must be taken to prevent freezing in cold regions, and if the equipment is installed outdoors, it may freeze in winter.

[0012] Therefore, there is an urgent need in the art to provide a novel, adjustable atmosphere, gas-based, direct reduction iron making system and method. Summary of the Invention

[0013] The present invention has been made to solve the above problems, and an object of the present invention is to provide a gas-based direct reduction iron-making system capable of adjusting the atmosphere.

[0014] Another object of the present invention is to provide a gas-based direct reduction ironmaking process with adjustable atmosphere. [Means for solving the problem]

[0015] In order to achieve the above object, in one aspect, the present invention provides an atmosphere-adjustable gas-based direct reduction iron-making system including a shaft furnace, a primary cooling device, a filtration device, a secondary cooling device, a pressurizing device, a combustion gas mixing device, a reducing gas mixing device, a preheating furnace, and a reforming furnace, wherein the combustion gas mixing device and the reducing gas mixing device are each provided with a plurality of gas inlet passages, a furnace top gas outlet of the shaft furnace is connected by a pipe to one gas inlet passage of each of the combustion gas mixing device and the reducing gas mixing device, via a primary cooling device, a filtering device, a secondary cooling device, and a pressurizing device in this order; and a gas outlet passage of the reducing gas mixing device is connected by a pipe to the gas inlet of the shaft furnace, via a preheating furnace and a reforming furnace in this order; The gas outlet passage of the combustion gas mixing device is connected to a burner of the reformer by a pipe, and an atmosphere-adjustable gas-based direct reduction iron-making system is provided.

[0016] As a specific embodiment of the above-mentioned atmosphere-adjustable gas-based direct reduction ironmaking system according to the present invention, the system further includes a reducing gas mixing device and a supplemental reducing gas source, the gas outlet of the reformer furnace is connected to the gas inlet of the shaft furnace via a pipe through the reducing gas mixing device, and the supplemental reducing gas source is connected to the supplemental reducing gas inlet of the reducing gas mixing device via a pipe.

[0017] In a specific embodiment of the above-described atmosphere-adjustable gas-based direct reduction ironmaking system according to the present invention, the furnace top gas outlet of the shaft furnace is further connected by a pipeline to the reducing gas mixer via a primary cooling device, a filtration device, a secondary cooling device, and a pressurization device in this order, thereby cooling and lowering the temperature of the mixed gas in the reducing gas mixer. In this case, the temperature-lowering cooler and / or the heating device can be selectively closed as needed, so that the mixed gas in the reducing gas mixer can be cooled and lowered using only a portion of the purified and pressurized furnace top gas.

[0018] In a specific embodiment of the above-mentioned atmosphere-adjustable gas-based direct reduction ironmaking system according to the present invention, the system further includes a temperature-reducing / cooling device and / or a heating device, and the gas outlet of the reformer furnace or the outlet of the reducing gas mixing device is connected to the gas inlet of the shaft furnace by a pipeline via the temperature-reducing / cooling device and / or the heating device. The temperature-reducing / cooling device and / or the heating device is provided at the shaft furnace inlet to adjust the temperature of the gas entering the shaft furnace, thereby matching the reduction reaction environment in the shaft furnace corresponding to different gas sources.

[0019] In a specific embodiment of the above-mentioned atmosphere-adjustable gas-based direct reduction iron-making system according to the present invention, a high-temperature flue gas outlet of a burner of the reformer furnace is connected by a pipe to a preheating medium gas inlet of the preheating furnace to preheat the target gas entering the preheating furnace.

[0020] In a specific embodiment of the above-described atmosphere-adjustable gas-based direct reduction iron-making system according to the present invention, the system further includes a chimney, and a preheating medium gas outlet of the preheating furnace is connected to the chimney by a pipe.

[0021] In a specific embodiment of the above-described atmosphere-adjustable gas-based direct reduction iron-making system according to the present invention, the system further includes a blower for blowing air into the reformer furnace.

[0022] In one specific embodiment of the above-described atmosphere-controllable gas-based direct reduction ironmaking system according to the present invention, the filtering device is a dry dust collector. A dry dust collector is a dust collector that dry-discharges ash removed from dust-containing gases, such as flue gas or gas, to be treated. A dry dust collector uses a bag filter to filter the dust-containing gas. When the dust-containing gas enters the bag filter, large particles with a high specific gravity settle by gravity and fall into a hopper, while gas containing relatively fine dust particles is blocked as it passes through the filter media, resulting in a purified dust-containing gas. As the dust on the surface of the bag filter increases, the programmer begins to operate, opening the pulse valves one by one to blow compressed air into the bag filter from the spout, rapidly inflating the bag filter. The reverse airflow rapidly detaches the dust adhering to the surface of the bag filter from the bag filter and drops it into the ash silo, where it is discharged through the dust discharge valve at the bottom of the ash silo.

[0023] In a specific embodiment of the above-mentioned atmosphere-adjustable gas-based direct reduction ironmaking system according to the present invention, the system further includes a plurality of gas surge tanks, and the plurality of gas inlet passages of the combustion gas mixing device, the plurality of gas inlet passages of the reducing gas mixing device, and the supplemental reducing gas inlet of the reducing gas mixing device are connected to the gas surge tanks, respectively.

[0024] In the present invention, when different gas sources are used, the ratio of CO to H in the generated reducing gas is different, and the direct reduction reaction atmosphere in the shaft furnace is accordingly different. Therefore, in the system provided by the present invention, the combustion gas mixing device and the reducing gas mixing device are each provided with multiple gas inlet passages, which can be used according to parameters such as the calorific value, flow rate, and pressure of the different gas sources.

[0025] To achieve such basic functions, the atmosphere-adjustable gas-based direct reduction iron-making system provided by the present invention may further include main equipment such as a power supply system, a control system, and a detection system.

[0026] In another aspect, the present invention provides (1) After cooling, purifying, and pressurizing the top gas of the shaft furnace, a portion of the top gas is sent to a reducing gas mixing device as a reducing gas and mixed with one or more reducing gas sources, the mixed reducing gas is sent to a preheating furnace and preheated, and another portion is sent to a combustion gas mixing device as a fuel gas and mixed with one or more fuel gas sources, the mixed fuel gas is sent to a burner of a reformer, and heat energy is supplied to the reformer; (2) feeding the preheated reducing gas into a reformer, catalytically reforming the preheated reducing gas by the catalytic action of a reforming catalyst to obtain a reducing gas, and then directly feeding the reducing gas into a shaft furnace to reduce and smelt the iron ore to produce direct reduced iron; Alternatively, when a reforming catalyst is not added to the reformer furnace, the present invention provides a gas-based direct reduction iron-making method capable of adjusting the atmosphere, which includes sending a preheated reducing gas to the reformer furnace to re-preheat it, and sending the re-preheated mixed gas to a shaft furnace to cause a self-reforming reaction in the shaft furnace to produce direct reduced iron.

[0027] As a specific embodiment of the above-mentioned atmosphere-adjustable gas-based direct reduction ironmaking method according to the present invention, the method further includes mixing the reducing gas discharged from the gas outlet of the reformer furnace with a supplemental reducing gas source in a reducing gas mixing device, and sending the resulting mixed gas directly to a shaft furnace to reduce and smelt iron ore to produce direct reduced iron.

[0028] In a specific embodiment of the above-mentioned atmosphere-adjustable gas-based direct reduction ironmaking method according to the present invention, the supplemental reducing gas source is hydrogen gas.

[0029] In a specific embodiment of the above-mentioned atmosphere-adjustable gas-based direct reduction ironmaking method according to the present invention, the method further includes feeding a portion of the purified and pressurized furnace top gas into a reducing gas mixing device, and cooling the mixed gas in the reducing gas mixing device to lower the temperature.

[0030] As a specific embodiment of the above-described atmosphere-adjustable gas-based direct reduction ironmaking method according to the present invention, the method further includes adjusting the temperature of the gas (which may be the reducing gas obtained after the reformer reaction, a mixed gas of the reducing gas obtained after the reformer reaction and a supplementary reducing gas source, or a mixed gas re-preheated in the reformer) entering the shaft furnace through the gas inlet of the shaft furnace by a temperature-lowering cooling device and / or a heating device.

[0031] In a specific embodiment of the above-described atmosphere-adjustable gas-based direct reduction ironmaking method according to the present invention, the method further includes preheating a target gas entering the preheating furnace with high-temperature flue gas generated by combustion in a burner of the reformer furnace.

[0032] In a specific embodiment of the above-mentioned atmosphere-adjustable gas-based direct reduction ironmaking method according to the present invention, the reducing gas source and the fuel gas source each include a combination of one or more of coalbed gas, natural gas, coke oven gas, reformed gas, and hydrogen gas, and the reformed gas includes a reformed gas enriched in one or more of CO, H, and CH.

[0033] In the present invention, the reducing gas source and the fuel gas source may be the same or different.

[0034] In one specific example of the atmosphere-adjustable gas-based direct reduction ironmaking method according to the present invention, the mixed reducing gas contains H, CO, and CH in a total volume ratio of 70% or more, Preferably, when a supplemental reducing gas source is used in the method, the combined volume of H (in this case, H may be H in the reducing gas mixture and H in the supplemental reducing gas source, or may be H only in the supplemental reducing gas source), CO, and CH in the combined reducing gas and supplemental reducing gas source is 70% or more of the total volume of the combined reducing gas and supplemental reducing gas source.

[0035] In one specific embodiment of the atmosphere-adjustable gas-based direct reduction ironmaking method according to the present invention, the furnace temperature of the reforming furnace is 1000 to 1100°C.

[0036] In the present invention, the furnace temperature of the reformer depends on parameters such as the components and calorific value of the gas source, and since the required thermal energy differs depending on the gas source, the furnace temperature of the corresponding reformer also differs.

[0037] In step (1) of the above-described atmosphere-adjustable gas-based direct reduction ironmaking method provided by the present invention, a portion of the purified and pressurized furnace top gas is fed as a reducing gas into a reducing gas mixing device and mixed with one or more reducing gas sources. The mixed reducing gas is then fed into a preheating furnace and preheated. Here, the mixing ratio of the purified and pressurized furnace top gas and the reducing gas source is adjusted depending on the type of reducing gas source. That is, the reducing gas ratio after mixing must be matched to the reducing gas source. The mixing ratio varies depending on the gas source, and the ratio of CO to H in the resulting reducing agent also varies.

[0038] In step (1) of the above-described gas-based direct reduction ironmaking process with adjustable atmosphere provided by the present invention, another portion of the purified and pressurized furnace top gas is fed as fuel gas to a combustion gas mixer and mixed with one or more fuel gas sources. The mixed fuel gas is fed to a burner of a reformer to supply thermal energy to the reformer. Here, the mixing ratio of the purified and pressurized furnace top gas and the fuel gas source is adjusted according to the properties and parameters of the fuel gas source. That is, when mixing two types of gases, the purified and pressurized furnace top gas and the fuel gas source, the ratio of the combustion gas obtained after mixing must be adjusted to match the gas source, and the thermal energy required for the catalytic reaction differs depending on the gas source.

[0039] In the method provided by the present invention, different gas sources need to be passed through the corresponding gas inlet passages of the combustion gas mixing device and the reducing gas mixing device, and at the same time, the ratio of CO and H in the reducing gas produced can be controlled by adjusting the gas mixing ratio, heating temperature, amount and particle size of the reforming catalyst corresponding to the gas sources.

[0040] In a preferred embodiment of the present invention, the reforming catalyst must be a nickel-based catalyst that can reform methane and carbon dioxide in gases such as coalbed gas into a reducing gas containing hydrogen and carbon monoxide in a predetermined ratio. This catalyst must have high activity, high selectivity, high temperature resistance, and carbon deposition resistance to meet the requirements for iron reduction using a hydrogen-based shaft furnace. The reforming catalyst must also have low gas resistance and low pressure drop so that the reducing gas outlet pressure meets the requirements for the inlet of the hydrogen-based shaft furnace. The particle size of the reforming catalyst must also be selected based on the height and diameter of the reforming furnace. For example, the particle size of the reforming catalyst used is 13 mm in diameter, adjustable within a range of 10 to 20 mm.

[0041] The reforming catalyst used in the present invention is a common catalyst used in the art, and may be commercially available or homemade in a laboratory.

[0042] Compared with the prior art, the adjustable atmosphere gas-based direct reduction iron making system and method provided by the present invention can achieve the following beneficial technical effects:

[0043] (1) In the system provided by the present invention, a cooling device and / or a heating device is provided at the gas inlet of the shaft furnace to adjust the reaction temperature in the shaft furnace to correspond to gas sources with different calorific values, thereby protecting the shaft furnace equipment and preventing the impact on the life of the shaft furnace caused by the gas temperature being too high, thereby realizing the design concept that the system and method are applicable to various gas sources.

[0044] (2) The present invention uses a double cooling and dry dust collection process for the top gas of the shaft furnace. Here, the use of double cooling reduces the equipment configuration for high-pressure dust collection, thereby reducing costs. The use of dry dust collection avoids environmental pollution caused by wet dust collection, saving energy and being environmentally friendly.

[0045] (3) The present invention provides a gas-based direct reduction ironmaking system and method that is applicable to various gas sources, has an adjustable atmosphere, and is environmentally friendly. The gas-based direct reduction ironmaking system and method can control the ratio of CO to H in the generated reducing gas, i.e., the H / C ratio of the generated reducing gas, by adjusting the use of a reforming catalyst according to the type of gas source. This system and method is applicable to various gas sources, adjusts the ratio of the generated reducing gas, and solves the problems of a single gas source and limited gas ratio. Furthermore, when a reforming catalyst is not added to the reformer furnace, self-reforming occurs within the shaft furnace. When a reforming catalyst is added to the reformer furnace, reforming occurs outside the shaft furnace, i.e., within the reformer furnace.

[0046] (4) The present invention recycles the furnace top gas of the shaft furnace after double cooling, dry dust collection and pressure treatment, i.e., effectively recycles and reuses CO2, thereby further achieving the goals of energy saving and environmental protection.

[0047] As described above, the present invention realizes green, low-carbon, and environmentally friendly concepts, and provides a diversified, low-cost, low-energy-consumption, low-emission, atmosphere-controllable, stable, efficient, and green gas-based direct reduction ironmaking system and method. [Brief explanation of the drawings]

[0048] In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the drawings necessary for explaining the embodiments will be briefly described below. Obviously, the drawings in the following description are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without making any creative efforts. [Figure 1] 1 is a schematic diagram showing the configuration of a gas-based direct reduction iron-making system capable of adjusting an atmospheric gas according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram showing the configuration of an atmosphere-adjustable gas-based direct reduction iron-making system according to a second embodiment of the present invention. [Figure 3]FIG. 10 is a schematic diagram showing the configuration of an atmosphere-adjustable gas-based direct reduction iron-making system according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram showing the configuration of an atmosphere-adjustable gas-based direct reduction iron-making system according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0049] The term "comprises" and any variations thereof in the present specification, claims, and drawings described above are used with the intent to cover a non-exclusive inclusion, e.g., a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those expressly recited, but may include other steps or units not expressly recited or inherent to such process, method, product, or apparatus.

[0050] In the present invention, the orientations or positional relationships indicated by terms such as "upper," "lower," "inner," "outer," and "middle" are based on the orientations or positional relationships shown in the drawings. These terms are primarily used to better explain the present invention and its embodiments, and are not used to limit the illustrated devices, elements, or components to have a specific orientation or to be configured and operated in a specific orientation.

[0051] Furthermore, some of the above terms may be used not only to represent orientation or positional relationships but also to represent other meanings. For example, the term "on" may be used in some cases to represent a specific associated or connected relationship. The specific meanings of these terms in the present invention can be understood by those skilled in the art from specific contexts.

[0052] Furthermore, the terms "arrangement" and "connection" should be understood broadly. For example, "connection" may be a fixed connection, a detachable connection, or an integral structure, may be a mechanical connection, or an electrical connection, may be a direct connection, an indirect connection via an intermediate medium, or may be an internal connection between two devices, elements, or components. The specific meaning of the above terms in the present invention can be understood by those skilled in the art from a specific situation.

[0053] The "ranges" disclosed in this invention are expressed in terms of lower and upper limits. There can be one or more lower and upper limits. A given range is defined by selecting one lower limit and one upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are combinable, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are recited for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if the recited minimum range values ​​are 1 and 2 and the recited maximum range values ​​are 3, 4, and 5, the following ranges can all be envisioned: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0054] In the present invention, unless otherwise specified, the numerical range "ab" is an abbreviation indicating any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0 to 5" in the present invention lists all real numbers between "0 and 5," and "0 to 5" is an abbreviation for the combination of these numerical values.

[0055] In the present invention, unless otherwise specified, the embodiments and preferred embodiments described in the present invention can be combined with each other to form new technical solutions.

[0056] In the present invention, unless otherwise specified, the constituent elements and preferred constituent elements described in the present invention can be combined with each other to form a new technical solution.

[0057] In order to clarify the objectives, technical solutions, and advantages of the present invention, the present invention will be described in more detail below with reference to the accompanying tables, drawings, and examples. The examples described below are some examples described to illustrate the present invention, but are not all examples of the present invention and do not limit the scope of the present invention. All other examples made by those skilled in the art based on the examples of the present invention without any creative effort are within the patentable scope of the present invention. Unless specific conditions are specified in the examples, the procedures are carried out under normal conditions or conditions recommended by the manufacturer. Reagents and equipment used without specifying the manufacturer are ordinary commercially available products.

[0058] Example 1 This embodiment provides an atmosphere-adjustable gas-based direct reduction ironmaking system having a structural schematic diagram shown in Figure 1. As can be seen from Figure 1, the atmosphere-adjustable gas-based direct reduction ironmaking system includes: The system includes a shaft furnace 1, a primary cooling device 2, a filtration device 3, a secondary cooling device 4, a pressurization device 5, a combustion gas mixing device 6, a reducing gas mixing device 7, a preheating furnace 8, a reforming furnace 9, and a plurality of gas surge tanks (referred to as a first gas surge tank, a second gas surge tank, ..., an m-th gas surge tank, and an n-th gas surge tank, respectively), The combustion gas mixing device 6 and the reducing gas mixing device 7 are each provided with a plurality of gas inlet passages, The furnace top gas outlet of the shaft furnace 1 is connected by a pipeline to one gas inlet passage of each of the combustion gas mixer 6 and the reducing gas mixer 7 via a primary cooling device 2, a filtration device 3, a secondary cooling device 4, and a pressurizing device 5 in that order, and the gas outlet passage of the reducing gas mixer 7 is connected by a pipeline to the gas inlet of the shaft furnace 1 via a preheating furnace 8 and a reforming furnace 9 in that order, The gas outlet passage of the combustion gas mixer 6 is connected to the burner of the reformer 9 by a pipe.

[0059] In this embodiment, when the reforming catalyst is loaded into the reforming furnace 9, the system may further include a reducing gas mixing device 10 and a supplemental reducing gas source, and the gas outlet of the reforming furnace 9 is connected by a pipe to the gas inlet of the shaft furnace 1 via the reducing gas mixing device 10, and the supplemental reducing gas source is connected by a pipe to the supplemental reducing gas inlet of the reducing gas mixing device 10.

[0060] In this embodiment, the system further includes a temperature-reducing / cooling device 11 and / or a heating device 12, and the gas outlet of the reforming furnace 9 or the outlet of the reducing gas mixing device 10 is connected by a pipe to the gas inlet of the shaft furnace 1 via the heating device 12 and / or the temperature-reducing / cooling device 11.

[0061] In this embodiment, the hot flue gas outlet of the burner of the reformer furnace 9 is connected by a pipe to the preheating medium gas inlet of the preheating furnace 8 to preheat the target gas entering the preheating furnace 8.

[0062] In this embodiment, the system further includes a chimney, and the preheating medium gas outlet of the preheating furnace 8 is connected to the chimney by a pipe.

[0063] In this embodiment, the system further includes a blower 13 for blowing air into the reformer 9 .

[0064] In this embodiment, the filtering device 3 is a dry dust collector.

[0065] In this embodiment, the plurality of gas inlet passages of the combustion gas mixing device 6, the plurality of gas inlet passages of the reducing gas mixing device 7, and the supplementary reducing gas inlet of the reducing gas mixing device 10 are connected to a first gas surge tank, a second gas surge tank, ..., an mth gas surge tank, and an nth gas surge tank, respectively.

[0066] Example 2 This embodiment provides an atmosphere-adjustable gas-based direct reduction ironmaking system having a structural schematic diagram shown in Figure 2. As can be seen from Figure 2, the atmosphere-adjustable gas-based direct reduction ironmaking system includes: The system includes a shaft furnace 1, a primary cooling device 2, a filtration device 3, a secondary cooling device 4, a pressurization device 5, a combustion gas mixing device 6, a reduction gas mixing device 7, a preheating furnace 8, a reforming furnace 9, a temperature-reducing and cooling device 11, a heating device 12, and one gas surge tank 100. The combustion gas mixing device 6 and the reducing gas mixing device 7 are each provided with a plurality of gas inlet passages, The furnace top gas outlet of the shaft furnace 1 is connected by a pipeline to one gas inlet passage of each of the combustion gas mixer 6 and the reducing gas mixer 7, via a primary cooling device 2, a filtration device 3, a secondary cooling device 4, and a pressurizing device 5 in that order; the gas outlet passage of the reducing gas mixer 7 is connected by a pipeline to the gas inlet of the shaft furnace 1, via a preheating furnace 8, a reforming furnace 9, a heating device 12, and a temperature-reducing / cooling device 11 in that order; The gas outlet passage of the combustion gas mixer 6 is connected to the burner of the reformer 9 by a pipe.

[0067] In this embodiment, the hot flue gas outlet of the burner of the reformer furnace 9 is connected by a pipe to the preheating medium gas inlet of the preheating furnace 8 to preheat the target gas entering the preheating furnace 8.

[0068] In this embodiment, the system further includes a chimney, and the preheating medium gas outlet of the preheating furnace 8 is connected to the chimney by a pipe.

[0069] In this embodiment, the system further includes a blower 13 for blowing air into the reformer 9 .

[0070] In this embodiment, the filtering device 3 is a dry dust collector.

[0071] In this embodiment, one of the plurality of gas inlet passages of the combustion gas mixing device 6 and one of the plurality of gas inlet passages of the reducing gas mixing device 7 are each connected to a gas surge tank 100 by a pipe, and the gas surge tank 100 is connected to an outside air source.

[0072] Example 3 This embodiment provides an atmosphere-adjustable gas-based direct reduction ironmaking system having a structural schematic diagram shown in Figure 3. As can be seen from Figure 3, the atmosphere-adjustable gas-based direct reduction ironmaking system includes: The system includes a shaft furnace 1, a primary cooling device 2, a filtration device 3, a secondary cooling device 4, a pressurization device 5, a combustion gas mixing device 6, a reducing gas mixing device 7, a preheating furnace 8, a reforming furnace 9, a reducing gas mixing device 10, a temperature-lowering and cooling device 11, a heating device 12, and two gas surge tanks (referred to as a first gas surge tank 200 and a second gas surge tank 300, respectively), and a supplemental H gas source is connected by a pipe to a supplemental reducing gas inlet of the reducing gas mixing device 10 via the second gas surge tank 300; The combustion gas mixing device 6 and the reducing gas mixing device 7 are each provided with a plurality of gas inlet passages, The furnace top gas outlet of the shaft furnace 1 is connected by a pipeline to one gas inlet passage of each of the combustion gas mixer 6 and the reducing gas mixer 7, via a primary cooling device 2, a filtration device 3, a secondary cooling device 4, and a pressurizing device 5 in that order; the gas outlet passage of the reducing gas mixer 7 is connected by a pipeline to the gas inlet of the shaft furnace 1, via a preheating furnace 8, a reforming furnace 9, a reducing gas mixer 10, a heating device 12, and a temperature-lowering / cooling device 11 in that order; The gas outlet passage of the combustion gas mixer 6 is connected to the burner of the reformer 9 by a pipe.

[0073] In this embodiment, the hot flue gas outlet of the burner of the reformer furnace 9 is connected by a pipe to the preheating medium gas inlet of the preheating furnace 8 to preheat the target gas entering the preheating furnace 8.

[0074] In this embodiment, the system further includes a chimney, and the preheating medium gas outlet of the preheating furnace 8 is connected to the chimney by a pipe.

[0075] In this embodiment, the system further includes a blower 13 for blowing air into the reformer 9 .

[0076] In this embodiment, the filtering device 3 is a dry dust collector.

[0077] In this embodiment, one of the plurality of gas inlet passages of the combustion gas mixing device 6 and one of the plurality of gas inlet passages of the reducing gas mixing device 7 are each connected to a first gas surge tank 200 by a pipe, and the first gas surge tank 200 is connected to an outside air source.

[0078] Example 4 This embodiment provides an atmosphere-adjustable gas-based direct reduction ironmaking system having a structural schematic diagram shown in Figure 4. As can be seen from Figure 4, the atmosphere-adjustable gas-based direct reduction ironmaking system includes: The system includes a shaft furnace 1, a primary cooling device 2, a filtration device 3, a secondary cooling device 4, a pressurization device 5, a combustion gas mixing device 6, a reducing gas mixing device 7, a preheating furnace 8, a reforming furnace 9, a temperature-reducing / cooling device 11, a heating device 12, and two gas surge tanks (referred to as a first gas surge tank 200 and a second gas surge tank 300, respectively), The combustion gas mixing device 6 and the reducing gas mixing device 7 are each provided with a plurality of gas inlet passages, The furnace top gas outlet of the shaft furnace 1 is connected by a pipeline to one gas inlet passage of each of the combustion gas mixer 6 and the reducing gas mixer 7, via a primary cooling device 2, a filtration device 3, a secondary cooling device 4, and a pressurizing device 5 in that order; the gas outlet passage of the reducing gas mixer 7 is connected by a pipeline to the gas inlet of the shaft furnace 1, via a preheating furnace 8, a reforming furnace 9, a heating device 12, and a temperature-reducing / cooling device 11 in that order; The gas outlet passage of the combustion gas mixer 6 is connected to the burner of the reformer 9 by a pipe.

[0079] In this embodiment, the high-temperature flue gas outlet of the burner of the reformer furnace 9 is connected to the preheating medium gas inlet of the preheating furnace 8 by a pipe line so as to preheat the target gas entering the preheating furnace 8 .

[0080] In this embodiment, the system further includes a chimney, and the preheating medium gas outlet of the preheating furnace 8 is connected to the chimney by a pipe.

[0081] In this embodiment, the system further includes a blower 13 for blowing air into the reformer 9 .

[0082] In this embodiment, the filtering device 3 is a dry dust collector.

[0083] In this embodiment, one of the plurality of gas inlet passages of the combustion gas mixing device 6 and one of the plurality of gas inlet passages of the reducing gas mixing device 7 are respectively connected to a first gas surge tank 200 by a pipe, and the first gas surge tank 200 is connected to an outside air source; The supplemental H2 gas source is connected by a pipe to another of the plurality of gas inlet passages of the reducing gas mixing device 7 via a second gas surge tank 300.

[0084] Example 5 This embodiment provides an atmosphere-adjustable gas-based direct reduction iron-making system that differs from the atmosphere-adjustable gas-based direct reduction iron-making system provided by embodiment 2 only in the following points.

[0085] The reforming furnace further includes a reducing gas mixing device and a supplementary reducing gas source, wherein the gas outlet of the reforming furnace is connected by a pipe to the gas inlet of the shaft furnace via the reducing gas mixing device, a heating device, and a temperature / cooling device in this order, and the supplementary reducing gas source is connected by a pipe to the supplementary reducing gas inlet of the reducing gas mixing device; The furnace top gas outlet of the shaft furnace is connected by a pipe to the reducing gas mixing device via a primary cooling device, a filtering device, a secondary cooling device and a pressurizing device in this order.

[0086] Example 6 This example provides an adjustable atmosphere gas-based direct reduction ironmaking method that utilizes the adjustable atmosphere gas-based direct reduction ironmaking system provided in Example 2. The method includes the following detailed steps:

[0087] (1) The furnace top gas (process gas) generated in the shaft furnace is cooled in a primary cooling device to a temperature where condensation does not occur in the filter, and then sent to the filter for purification and dust collection in order to significantly reduce the performance parameters and costs of the high-pressure dust collection equipment. After purification and dust collection, the gas is sent sequentially to a secondary cooling device and a pressurizing device, where secondary cooling and pressurization are performed sequentially, resulting in purified and pressurized furnace top gas. A portion of the purified and pressurized furnace top gas is sent to a reducing gas mixer as reducing gas, where it is mixed with coalbed gas (supplementary gas) and then sent to a preheating furnace for preheating. Another portion of the purified and pressurized furnace top gas is sent to a combustion gas mixer as fuel gas, where it is mixed with coalbed gas (supplementary gas). The mixed fuel gas is sent to the burner of the reformer and heat energy is supplied to the reformer so that the furnace temperature of the reformer, i.e., the catalytic reforming reaction temperature, becomes 1000-1100°C.

[0088] The data on the furnace top gas and coalbed gas used in this example, as well as the gas blending ratios in the combustion gas mixer and reducing gas mixer, are shown in Table 1 below.

[0089] [Table 1]

[0090] (2) The preheated reducing gas is sent to a reformer filled with a reforming catalyst and equipped with high-temperature radiant tubes through which the preheated reducing gas flows. The thermal energy generated by the burner combustion is transferred to the reducing gas (mixed gas) inside the tube through the high-temperature radiant tube, heating the mixed gas. Due to the catalytic action of the reforming catalyst, CO2 and CH4 undergo an endothermic catalytic reforming reaction in the reformer, converting CH4 to CO+H2>90v%, H2 / (CO+H2)>50v%, with a gas oxidation degree not exceeding 5%. After catalytic reforming, high-temperature reducing gas is generated, i.e., the reducing gas. The high-temperature flue gas generated by combustion in the reformer burner is discharged and then enters a preheater, where the reducing gas is preheated before entering the reformer and then discharged.

[0091] Furthermore, a cooling device and a heating device at the entrance of the shaft furnace are used to adjust the temperature required for the direct reduction reaction in the shaft furnace, i.e., the temperature of the high-temperature reducing gas. The adjusted high-temperature reducing gas, with an inlet temperature of 950 to 1050°C, is then directly fed into the shaft furnace to reduce and smelt the iron ore (or pellets) to produce direct reduced iron, achieving a direct reduction conversion rate of >70%.

[0092] Example 7 This example provides an adjustable atmosphere gas-based direct reduction ironmaking method that utilizes the adjustable atmosphere gas-based direct reduction ironmaking system provided in Example 3. The method includes the following detailed steps:

[0093] (1) The furnace top gas (process gas) generated in the shaft furnace is primarily cooled, purified, secondarily cooled, and pressurized. A portion of the purified and pressurized furnace top gas is sent to a reducing gas mixer as reducing gas, where it is mixed with coalbed gas (supplementary gas) and then sent to a preheating furnace for preheating. Another portion of the purified and pressurized furnace top gas is sent to a combustion gas mixer as fuel gas, where it is mixed with coalbed gas (supplementary gas). The mixed fuel gas is sent to the burner of the reformer, where it supplies thermal energy to the reformer so that the furnace temperature, i.e., the catalytic reforming reaction temperature, reaches 1000-1100°C.

[0094] (2) The preheated reducing gas is sent to a reformer filled with a reforming catalyst and equipped with a high-temperature radiant tube through which the preheated reducing gas flows. The thermal energy generated by the burner combustion is transferred to the reducing gas (mixed gas) inside the tube through the high-temperature radiant tube. The mixed gas is heated and the catalytic action of the reforming catalyst causes CO2 and CH4 to undergo an endothermic catalytic reforming reaction in the reformer, converting CH4 to CO + H2 > 90v%, H2 / (CO + H2) > 50v%, with a gas oxidation degree not exceeding 5%. After catalytic reforming, high-temperature reducing gas (reducing gas) is generated. This high-temperature reducing gas contains approximately 95% CO and H2. The high-temperature flue gas generated by combustion in the reformer burner is discharged and then enters a preheating furnace to preheat the reducing gas before entering the reformer.

[0095] The data on the furnace top gas and coalbed gas used in this example, as well as the gas blending ratios in the combustion gas mixer and reducing gas mixer (including the reducing gas mixer) are shown in Table 2 below.

[0096] [Table 2]

[0097] In the reducing gas mixing device, the high-temperature reducing gas is mixed proportionally with H2, and the cooling device and heating device at the entrance of the shaft furnace are used to adjust the temperature required for the direct reduction reaction in the shaft furnace. That is, the temperature of the resulting mixed reducing gas is adjusted. The adjusted mixed reducing gas with an inlet temperature of 950 to 1050°C is then directly fed into the shaft furnace to reduce and smelt iron ore (or pellets) to produce direct reduced iron, achieving a direct reduction conversion rate of >70%.

[0098] Example 8 This example provides an atmosphere-adjustable gas-based direct reduction ironmaking method that utilizes the atmosphere-adjustable gas-based direct reduction ironmaking system provided in Example 4. The method includes the following detailed steps:

[0099] (1) The furnace top gas (process gas) generated in the shaft furnace is primarily cooled, purified, secondarily cooled, and pressurized. A portion of the purified and pressurized furnace top gas is sent to a reducing gas mixer as reducing gas, where it is mixed with coalbed gas (supplementary gas) and H2 (supplementary gas), and sent to a preheating furnace for preheating. The H2 content is 70-90% by volume, and the coalbed gas content is 30-10% by volume. Another portion of the purified and pressurized furnace top gas is sent to a combustion gas mixer as fuel gas, where it is mixed with coalbed gas (supplementary gas). The mixed fuel gas is sent to the burner of the reforming furnace, where it supplies thermal energy to the reforming furnace so that the furnace temperature is 1000-1100°C. In this example, the preheating furnace is a single-stage preheating furnace, the reforming furnace is a two-stage preheating furnace, and no reforming catalyst is added to the reforming furnace.

[0100] The data on the furnace top gas and coalbed gas used in this example, as well as the gas blending ratios in the combustion gas mixer and reducing gas mixer, are shown in Table 3 below.

[0101] [Table 3]

[0102] (2) The preheated reducing gas is sent to a reforming furnace and re-preheated. The cooling and heating devices at the entrance of the shaft furnace are used to adjust the temperature required for the direct reduction reaction in the shaft furnace. In other words, the temperature of the mixed gas obtained after re-preheating is adjusted. The mixed gas, with an entrance temperature of 850 to 950°C after adjustment, is sent to the shaft furnace and undergoes a self-reforming reaction with the iron ore in the shaft furnace to produce directly reduced iron.

[0103] Here, in the self-reforming reaction process, CH4 is converted so that CO+H2>60v%, H2 / (CO+H2)>40v%, and the gas oxidation degree does not exceed 5%.

[0104] Compared with the prior art, the adjustable atmosphere gas-based direct reduction iron making system and method provided by the embodiments of the present invention can achieve the following beneficial technical effects:

[0105] (1) In the system provided by the embodiment of the present invention, in order to adjust the reaction temperature in the shaft furnace corresponding to the gas sources with different calorific values, a cooling device and / or a heating device is provided at the gas inlet of the shaft furnace to adjust the temperature of the gas entering the shaft furnace, which can protect the shaft furnace equipment and prevent the impact on the life of the shaft furnace caused by the gas temperature entering the furnace being too high, thereby realizing the design concept that the system and method are applicable to various gas sources.

[0106] (2) The embodiment of the present invention uses a double cooling and dry dust collection process for the top gas of the shaft furnace. Here, the use of double cooling reduces the equipment configuration for high-pressure dust collection, thereby reducing costs. The use of dry dust collection avoids environmental pollution caused by wet dust collection, saving energy and being environmentally friendly.

[0107] (3) An embodiment of the present invention provides a gas-based direct reduction ironmaking system and method that is applicable to various gas sources, has an adjustable atmosphere, and is environmentally friendly. The gas-based direct reduction ironmaking system and method can control the ratio of CO to H in the generated reducing gas, i.e., the H / C ratio of the generated reducing gas, by adjusting the use of a reforming catalyst according to the type of gas source. This system and method is applicable to various gas sources, adjusts the ratio of the generated reducing gas, and solves the problems of a single gas source and limited gas ratio. Furthermore, when a reforming catalyst is not added to the reformer furnace, self-reforming occurs within the shaft furnace. When a reforming catalyst is added to the reformer furnace, reforming occurs outside the shaft furnace, i.e., within the reformer furnace.

[0108] (4) The present invention further achieves the goals of energy conservation and environmental protection by recycling the furnace top gas of the shaft furnace after double cooling, dry dust collection and pressure treatment, i.e., effectively recycling and recycling CO2.

[0109] As described above, the embodiments of the present invention realize concepts such as green, low-carbon, and environmental protection, and provide a diversified, low-cost, low-energy-consumption, low-emission, adjustable-atmosphere, stable, efficient, and green gas-based direct reduction ironmaking system and method.

[0110] The above description is merely a specific example of the present invention and is not intended to limit the scope of the present invention, and therefore, any equivalent replacement of elements or equivalent changes and modifications based on the scope of the claims of the present invention should be construed as belonging to the scope of the present invention. In addition, the constituent elements of the present invention, the constituent elements and technical solutions, and the technical solutions can all be freely combined. [Explanation of symbols]

[0111] 1. Shaft furnace 2. Primary cooling device 3. Filtration device 4. Secondary cooling device 5. Pressurization device 6. Combustion gas mixing device 7. Reducing gas mixing device 8. Preheating furnace 9. Reforming furnace 10. Reducing gas mixing device 11. Temperature-lowering and cooling device 12. Heating device 13. Blower 100. Gas surge tank 200. First gas surge tank 300. Second gas surge tank

Claims

1. 1. A method for controlling atmosphere gas-based direct reduction ironmaking carried out using a controlling atmosphere gas-based direct reduction ironmaking system, comprising: the system includes a shaft furnace, a primary cooling device, a filtration device, a secondary cooling device, a pressurization device, a combustion gas mixing device having a plurality of gas inlet passages, a reduction gas mixing device having a plurality of gas inlet passages, a preheating furnace, and a reforming furnace; a furnace top gas outlet of the shaft furnace is connected by a pipeline to at least one of the gas inlet passages of the combustion gas mixing device and the reducing gas mixing device, successively via the primary cooling device, the filtration device, the secondary cooling device, and the pressurization device; a gas outlet passage of the reducing gas mixing device is connected to a gas inlet of the shaft furnace via a pipeline, successively passing through the preheating furnace and the reforming furnace; a gas outlet passage of the combustion gas mixing device connected to a burner of the reforming furnace by a pipe; The system further includes a cooling device and a heating device; a gas outlet of the reformer furnace is connected to a gas inlet of the shaft furnace via a pipeline, successively via the temperature-lowering / cooling device and the heating device; The filtering device is a dry dust collector, The method comprises: (1) After the shaft furnace top gas is primarily cooled, purified, secondarily cooled, and pressurized, a portion of the gas is sent to a reducing gas mixing device as a reducing gas and mixed with one or more reducing gas sources, the mixed reducing gas is sent to a preheating furnace and preheated, and the other portion is sent to a combustion gas mixing device as a fuel gas and mixed with one or more fuel gas sources, the mixed fuel gas is sent to a burner of a reforming furnace, and thermal energy is supplied to the reforming furnace; (2) feeding the preheated reducing gas into a reformer, catalytically reforming the preheated reducing gas by the catalytic action of a reforming catalyst to obtain a reducing gas, and then directly feeding the reducing gas into a shaft furnace to reduce and smelt the iron ore to produce direct reduced iron; Alternatively, when a reforming catalyst is not added to the reformer furnace, the method includes sending a preheated reducing gas to the reformer furnace to re-preheat it, and sending the re-preheated mixed gas to a shaft furnace to cause a self-reforming reaction in the shaft furnace to produce directly reduced iron, 1. A gas-based direct reduction ironmaking method with adjustable atmosphere, further comprising adjusting the temperature of gas entering the shaft furnace through a gas inlet of the shaft furnace by a cooling device and a heating device.

2. 2. The atmosphere-adjustable gas-based direct reduction ironmaking method according to claim 1, further comprising a reducing gas mixing device and a supplemental reducing gas source, wherein a gas outlet of the reformer furnace is connected by a pipe to a gas inlet of the shaft furnace via the reducing gas mixing device, and the supplemental reducing gas source is connected by a pipe to a supplemental reducing gas inlet of the reducing gas mixing device.

3. 3. The atmosphere-controllable gas-based direct reduction ironmaking method according to claim 2, wherein an outlet of the reducing gas mixing device is connected to a gas inlet of the shaft furnace by a pipeline via the temperature-lowering / cooling device and the heating device.

4. 2. The atmosphere-controllable gas-based direct reduction ironmaking method according to claim 1, wherein a high-temperature flue gas outlet of a burner of the reformer furnace is connected by a pipe to a preheating medium gas inlet of the preheating furnace for preheating the target gas entering the preheating furnace.

5. 5. The method of claim 4, further comprising a chimney, wherein a preheating medium gas outlet of the preheating furnace is connected to the chimney by a pipe.

6. 2. The gas-based direct reduction iron-making method according to claim 1, further comprising a blower for blowing air into the reformer furnace.

7. 2. The atmosphere-controllable gas-based direct reduction ironmaking method according to claim 1, further comprising a plurality of gas surge tanks, wherein the plurality of gas inlet passages of the combustion gas mixing device, the plurality of gas inlet passages of the reducing gas mixing device, and the supplemental reducing gas inlet of the reducing gas mixing device are connected to the gas surge tanks, respectively.

8. 2. The method of claim 1, further comprising: mixing the reducing gas discharged from the gas outlet of the reformer furnace with a supplemental reducing gas source in a reducing gas mixing device; and sending the resulting mixed gas directly to a shaft furnace to reduce and smelt iron ore to produce direct reduced iron.

9. 2. The atmosphere-controllable gas-based direct reduction ironmaking method according to claim 1, further comprising preheating the target gas entering the preheating furnace with high-temperature flue gas generated by combustion in a burner of the reformer furnace.

10. The reducing gas source and the fuel gas source each include one or more combinations of coal seam gas, natural gas, coke oven gas, reformed gas, and hydrogen gas, and the reformed gas is preferably a mixture of CO, H ２ , and C.H. ４ 2. The atmosphere-tunable gas-based direct reduction ironmaking process according to claim 1, wherein the reforming gas is enriched in one or more of the following:

11. When a supplemental reducing gas source is used, the combined reducing gas and supplemental reducing gas source contain H ２ , CO, and CH ４ 9. The atmosphere-controllable gas-based direct reduction ironmaking process according to claim 8, wherein the total volume ratio of the above is 70% or more.

12. The atmosphere-adjustable gas-based direct reduction ironmaking method as described in claim 1, characterized in that the total volume of H 2 , CO, and CH 4 accounts for 70% or more of the total volume of the mixed reducing gas.

13. The atmosphere-adjustable gas-based direct reduction ironmaking method according to claim 1, characterized in that the furnace temperature of the reforming furnace is 1000 to 1100°C.

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