Blast furnace gas membrane separation process and blast furnace gas membrane separation system

Abstract

The invention relates to the technical field of blast furnace gas separation, in particular to a blast furnace gas membrane separation process and a blast furnace gas membrane separation system. The blast furnace gas membrane separation technology comprises the following steps that blast furnace gas is introduced into a primary membrane separation unit to be separated into first mixed gas and second mixed gas, the permeability coefficient ratio of a membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide is larger than or equal to 2, the first mixed gas is introduced into a first membrane separation unit, and the second mixed gas is introduced into a second membrane separation unit; the permeability coefficient ratio of the membrane of the first membrane separation unit to carbon monoxide and nitrogen is larger than or equal to 10, the second mixed gas is introduced into a second membrane separation unit, and the permeability coefficient ratio of the membrane of the second membrane separation unit to hydrogen and carbon dioxide is larger than or equal to 75. According to the method, all-component gas in the blast furnace gas is creatively recovered only by using membranes with different properties, and meanwhile, the purity and the recovery rate of the recovered gas in the blast furnace gas are improved.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace gas separation, and in particular to a blast furnace gas membrane separation process and a blast furnace gas membrane separation system. Background Art

[0002] As one of the major contributors to anthropogenic CO2 emissions, accounting for approximately 7% of global CO2 emissions, the steel industry is under tremendous pressure to achieve decarbonization while maintaining economic viability. This tension between environmental sustainability and industrial productivity has stimulated extensive research into innovative technologies that can bridge this gap. Among them, the efficient utilization and separation of blast furnace gas (BFG) has emerged as a promising avenue for reducing emissions and optimizing resources. BFG is a byproduct of the ironmaking process and is mainly composed of carbon monoxide (CO, 20-30%), carbon dioxide (CO2, 20-30%), hydrogen (H2, 1-5%), and nitrogen (N2, 45-55%). Traditionally, BFG has been regarded as a low-value waste and is usually burned for heat recovery or power generation. However, this approach fails to fully utilize the full potential of its component gases, especially CO and H2, which are valuable raw materials for chemical synthesis and clean energy applications. The current status of global BFG treatment shows a significant gap between its potential value and actual utilization.

[0003] Traditional blast furnace gas treatment technologies mainly include combustion power generation, chemical absorption, low-temperature separation and pressure swing adsorption. These methods have problems such as high energy consumption, low efficiency and high cost. For example, chemical absorption can effectively capture CO2 with a capture rate of 95%, but the commonly used MEA solution regeneration energy consumption is as high as 3-4 GJ / ton CO2. The low-temperature separation method uses the boiling point of each component to achieve a CO2 separation purity of 95%, but the energy consumption is as high as 0.35-0.45 kWh / m³ BFG. The pressure swing adsorption method can achieve gas separation and recovery, but studies have shown that when the pressure swing adsorption method is used to recover gas, the gas recovery rate and purity are negatively feedback, that is, when the gas purity is high, the gas recovery rate decreases.

[0004] Currently, researchers are trying to use membrane separation technology in combination with traditional processing technology to separate blast furnace gas, but they are still unable to separate and recover all gases in blast furnace gas, and the recovery rate and purity of the separated gas are not high. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that all gases in blast furnace gas cannot be separated with high recovery rate and high purity, thereby providing a blast furnace gas membrane separation process and a blast furnace gas membrane separation system, which can effectively capture and recover high-value and low-concentration H2 and CO while capturing CO2.

[0006] On the one hand, the present invention provides a blast furnace gas membrane separation process, comprising the following steps: passing blast furnace gas into a primary membrane separation unit to separate it into a first mixed gas and a second mixed gas, wherein the first mixed gas includes carbon monoxide and nitrogen, and the second mixed gas includes carbon dioxide and hydrogen, and the ratio of the permeability coefficients of the membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide is greater than or equal to 2; passing the first mixed gas into a first membrane separation unit to separate it into a mixed gas containing nitrogen and a mixed gas containing carbon monoxide, and the ratio of the permeability coefficients of the membrane of the first membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 10; passing the second mixed gas into a second membrane separation unit to separate it into a mixed gas containing carbon dioxide and a mixed gas containing hydrogen, and the ratio of the permeability coefficients of the membrane of the second membrane separation unit to hydrogen and carbon dioxide is greater than or equal to 75.

[0007] In an embodiment of the present invention, the first mixed gas separated by the primary membrane separation unit is injected into the first membrane separation unit to improve the recovery rate of carbon monoxide, and the second mixed gas is injected into the second membrane separation unit to improve the recovery rates of carbon dioxide and hydrogen. The present invention adopts a multi-stage membrane unit to control the product recovery rate and product purity. Different gases have different permeability coefficients in the membrane, and a multi-stage recovery and regulation membrane system is ingeniously designed. The recovery of all components of gas in blast furnace gas is creatively achieved by only using membranes with different properties, and at the same time, the purity and recovery rate of the recovered gas in blast furnace gas are improved.

[0008] Exemplarily, the ratio of the permeability coefficients of the membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide is 2, 5, 10, 16, 25, 30, 50, 65, 80, 84, 100 or higher. It should be noted that the higher the ratio of the permeability coefficients of the membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide, the better the separation effect.

[0009] Exemplarily, the permeability coefficient ratio of the first membrane separation unit membrane to carbon monoxide and nitrogen is 10, 12, 15, 20, 28, 30, 40, 50, 60 or higher. It should be noted that the higher the permeability coefficient ratio of the first membrane separation unit membrane to carbon monoxide and nitrogen, the better the separation effect.

[0010] Exemplarily, the ratio of the permeability coefficients of the second membrane separation unit membrane to hydrogen and carbon dioxide is 75, 80, 95, 102, 110, 120, 130, 150 or higher. It should be noted that the higher the ratio of the permeability coefficients of the second membrane separation unit membrane to hydrogen and carbon dioxide, the better the separation effect.

[0011] In order to further improve the purity of each component gas of the recovered blast furnace gas, in some embodiments, in order to improve the purity of the recovered carbon monoxide, the blast furnace gas membrane separation process further includes passing the concentrated carbon monoxide-containing mixed gas into a first purification membrane separation unit for purification to obtain carbon monoxide, and the ratio of the permeability coefficient of the membrane of the first purification membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 10. Exemplarily, the ratio of the permeability coefficient of the membrane of the first purification membrane separation unit to carbon monoxide and nitrogen is 10, 15, 20, 40, 50, 65, 80 or a higher ratio. It should be noted that the higher the ratio of the permeability coefficient of the membrane of the first purification membrane separation unit to carbon monoxide and nitrogen, the better the separation effect.

[0012] In order to improve the purity of the recovered carbon dioxide, the concentrated mixed gas containing carbon dioxide is passed into the second purification membrane separation unit for purification to obtain carbon dioxide, and the ratio of the permeability coefficients of the membrane in the second purification membrane separation unit to carbon dioxide and hydrogen is greater than or equal to 160. Exemplarily, the ratio of the permeability coefficients of the membrane in the second purification membrane separation unit to carbon dioxide and hydrogen is 160, 165, 178, 180, 200, 220, 250 or a higher ratio. It should be noted that the higher the ratio of the permeability coefficients of the membrane in the second purification membrane separation unit to carbon dioxide and hydrogen, the better the separation effect.

[0013] In order to improve the purity of the recovered hydrogen, the concentrated hydrogen-containing mixed gas is passed into the third purification membrane separation unit for purification to obtain hydrogen, and the ratio of the permeability coefficients of the membrane in the third purification membrane separation unit to hydrogen and carbon dioxide is greater than or equal to 75. Exemplarily, the ratio of the permeability coefficients of the membrane in the third purification membrane separation unit to hydrogen and carbon dioxide is 75, 80, 95, 110, 150, 200, 220 or a higher ratio. It should be noted that the higher the ratio of the permeability coefficients of the membrane in the third purification membrane separation unit to hydrogen and carbon dioxide, the better the separation effect.

[0014] In order to optimize the separation efficiency of the separation process, in some embodiments, the ratio of the permeability coefficients of the membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide is greater than or equal to 16. Preferably, the membrane in the primary membrane separation unit is at least one of a hollow fiber carbon membrane and a carbon dioxide selective membrane.

[0015] The permeability coefficient ratio of the first membrane separation unit membrane to carbon monoxide and nitrogen is greater than or equal to 15, Preferably, the membrane in the first membrane separation unit is at least one of a solid facilitated transport composite membrane and a carbon monoxide selective membrane.

[0016] The permeability coefficient ratio of the second membrane separation unit membrane to hydrogen and carbon dioxide is greater than or equal to 80, Preferably, the membrane in the second membrane separation unit is at least one of a hollow fiber carbon membrane and a hydrogen selective membrane.

[0017] The permeability coefficient ratio of the membrane of the first purification membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 15; Preferably, the membrane of the first purification membrane separation unit is at least one of a solid-state facilitated transport composite membrane, a carbon monoxide selective membrane, and a nitrogen selective membrane.

[0018] The permeability coefficient ratio of the second purification membrane separation unit membrane to carbon dioxide and hydrogen is greater than or equal to 180, Preferably, the membrane of the second purification membrane separation unit is at least one of a facilitated transport composite membrane, a carbon dioxide selective membrane or a hydrogen selective membrane.

[0019] The permeability coefficient ratio of the third purification membrane separation unit membrane to hydrogen and carbon dioxide is greater than or equal to 80, Preferably, the membrane of the third purification membrane separation unit is at least one of a hollow fiber carbon membrane, a hydrogen selective membrane or a carbon dioxide selective membrane.

[0020] Furthermore, in order to optimize the separation process of blast furnace gas and improve the separation efficiency of each group of gases, in some embodiments, the gas pressure entering the primary membrane separation unit is 2-20 bar, and the gas temperature is 25-200°C; the gas pressure entering the first membrane separation unit is 2-10 bar, and the gas temperature is 25-80°C; the gas pressure entering the second membrane separation unit is 2-20 bar, and the gas temperature is 25-200°C; the gas pressure entering the first purification membrane separation unit is 2-10 bar, and the gas temperature is 25-80°C; the gas pressure entering the second purification membrane separation unit is 2-5 bar, and the gas temperature is 25-80°C; the gas pressure entering the third purification membrane separation unit is 2-20 bar, and the gas temperature is 25-200°C.

[0021] In order to further improve the recovery rate of each component of blast furnace gas, the blast furnace gas membrane separation process provided in the embodiment of the present invention also includes the step of recycling the unpurified mixed gas to the first membrane separation unit and / or the second membrane separation unit, and separating and purifying the insufficiently separated mixed gas again.

[0022] On the other hand, the present invention provides a blast furnace gas membrane separation system, which adopts the above-mentioned blast furnace gas membrane separation process, and the membrane separation system includes a primary membrane separation unit, a first membrane separation unit and a second membrane separation unit connected to the primary membrane separation unit, and the primary membrane separation unit is used to separate the blast furnace gas into a first mixed gas and a second mixed gas, wherein the first mixed gas includes carbon monoxide and nitrogen, and the second mixed gas includes carbon dioxide and hydrogen, and the permeability coefficient ratio of the membrane of the primary membrane separation unit to carbon dioxide and carbon monoxide is greater than or equal to 2, The first membrane separation unit is used to separate the first mixed gas into a mixed gas containing nitrogen and a mixed gas containing carbon monoxide, and the permeability coefficient ratio of the membrane in the first membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 10. The second membrane separation unit is used to separate the second mixed gas into a mixed gas containing carbon dioxide and a mixed gas containing hydrogen. The permeability coefficient ratio of the membrane in the second membrane separation unit to hydrogen and carbon dioxide is greater than or equal to 75.

[0023] Preferably, the primary membrane separation unit comprises a primary membrane separation assembly, a first compressor and a first heat exchanger.

[0024] In some embodiments, the first membrane separation unit is connected to a first purification membrane separation unit.

[0025] Preferably, the first membrane separation unit includes a first membrane separation assembly, and more preferably, the first membrane separation unit further includes a sixth compressor and a sixth heat exchanger.

[0026] Preferably, the first purification membrane separation unit comprises a first purification membrane separation assembly, a third compressor and a third heat exchanger.

[0027] In some embodiments, the second membrane separation unit is connected to a second purification membrane separation unit.

[0028] Preferably, the second membrane separation unit comprises a second membrane separation assembly, a second compressor and a second heat exchanger.

[0029] Preferably, the second purification membrane separation unit comprises a second purification membrane separation assembly, a fourth compressor and a fourth heat exchanger; In some embodiments, the second membrane separation unit is connected to a third purification membrane separation unit.

[0030] Preferably, the third purification membrane separation unit comprises a third purification membrane separation assembly, a fifth compressor and a fifth heat exchanger.

[0031] In some embodiments, the blast furnace gas membrane separation system further includes a first recovery unit, a second recovery unit and a third recovery unit. The first recovery unit is connected to the first purification membrane separation unit and is used to recover the mixed gas intercepted by the first purification membrane separation unit to the first membrane separation unit. The second recovery unit is connected to the second purification membrane separation unit and is used to recover the mixed gas intercepted by the second purification membrane separation unit to the first membrane separation unit. The third recovery unit is connected to the third purification membrane separation unit and is used to recover the mixed gas intercepted by the third purification membrane separation unit to the second membrane separation unit.

[0032] The technical solution of the present invention has the following advantages: 1. A blast furnace gas membrane separation process provided by the present invention comprises the following steps: passing blast furnace gas into a primary membrane separation unit to separate it into a first mixed gas and a second mixed gas, wherein the first mixed gas comprises carbon monoxide and nitrogen, and the second mixed gas comprises carbon dioxide and hydrogen, and the ratio of the permeability coefficients of the membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide is greater than or equal to 2; passing the first mixed gas into a first membrane separation unit to separate it into a mixed gas containing nitrogen and a mixed gas containing carbon monoxide, and the ratio of the permeability coefficients of the membrane of the first membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 10; controlling the recovery rate of carbon monoxide; passing the second mixed gas into a second membrane separation unit to separate it into a mixed gas containing carbon dioxide and a mixed gas containing hydrogen, and the ratio of the permeability coefficients of the membrane of the second membrane separation unit to hydrogen and carbon dioxide is greater than or equal to 75, and controlling the recovery rates of carbon dioxide and hydrogen at the same time. The present invention adopts a multi-stage membrane unit to control the product recovery rate and product purity. Different gases have different permeability coefficients in the membrane, and a multi-stage recovery and regulation membrane system is ingeniously designed. The recovery of all components of gas in blast furnace gas is creatively achieved by only using membranes with different properties, and at the same time, the purity and recovery rate of the recovered gas in blast furnace gas are improved.

[0033] 2. The present invention provides a blast furnace gas membrane separation process, which also includes passing carbon monoxide into a first purification membrane separation unit to purify carbon monoxide and control the purity of carbon dioxide; passing carbon dioxide into a second purification membrane separation unit to purify carbon dioxide; and passing hydrogen into a third purification membrane separation unit to purify hydrogen. Under the premise of realizing the recovery of all components of blast furnace gas, the present invention adds a step of purifying each recovered gas by membrane treatment, further improving the recovery purity of single-component gas of blast furnace gas, wherein a plurality of series-parallel combinations are set in the form of the first membrane separation unit and the second membrane separation unit in parallel, the first membrane separation unit and the first purification membrane separation unit in series, the second membrane separation unit and the second purification membrane separation unit and the third purification membrane separation unit in series to improve the separation of each gas component of blast furnace gas, at the same time, the first recovery unit, the second recovery unit and the third recovery unit are set, and the recovery rate of each gas component of blast furnace gas is improved by a three-way reflux method, and the first membrane separation unit can directly discharge nitrogen that meets the emission standards by setting a bypass, simplifying the recovery process and improving the recovery efficiency, and the present invention achieves the best separation effect by setting strategies including series-parallel combination, reflux and bypass. This flexible configuration allows the system to be dynamically adjusted according to the feed composition and target product requirements, and can control the energy consumption at 0.1-0.15 kWh / m³ / BFG.

[0034] 3. The blast furnace gas membrane separation process provided by the present invention has a gas pressure of 2-20 bar and a gas temperature of 25-200°C when entering the primary membrane separation unit; a gas pressure of 2-10 bar and a gas temperature of 25-80°C when entering the first membrane separation unit; a gas pressure of 2-20 bar and a gas temperature of 25-200°C when entering the second membrane separation unit; a gas pressure of 2-10 bar and a gas temperature of 25-80°C when entering the first purification membrane separation unit; a gas pressure of 2-5 bar and a gas temperature of 25-80°C when entering the second purification membrane separation unit; and a gas pressure of 2-20 bar and a gas temperature of 25-200°C when entering the third purification membrane separation unit. By optimizing the gas pressure and temperature entering each membrane separation unit, the present invention can promote the gas to pass through the membrane in each membrane separation unit on the one hand, and can accurately control the separation effect of each separation stage on the other hand, thereby achieving the improvement of the purity and recovery rate of each component gas.

[0035] 4. The present invention provides a blast furnace gas membrane separation system, which adopts the above-mentioned blast furnace gas membrane separation process; wherein the membrane separation system comprises a primary membrane separation unit, a first membrane separation unit connected to the primary membrane separation unit, and a second membrane separation unit. The present invention realizes efficient blast furnace gas full component separation through continuous operation of multi-stage membrane separation units, occupies a small area, has low operating costs, and is environmentally friendly.

[0036] 5. The blast furnace gas membrane separation system provided by the present invention can not only provide strong technical support for the green transformation of the steel industry, but also have a profound impact on multiple fields such as energy utilization, environmental protection, and chemical production. The high recovery rate of each gas component means higher resource utilization efficiency. The efficient separation and utilization of blast furnace gas can significantly reduce greenhouse gas emissions in the steel industry. In particular, the efficient separation of CO2 provides a basis for subsequent carbon capture and utilization or storage technology, which helps to achieve the goal of carbon neutrality. High-purity gas products give products higher economic value and open up new business areas for steel companies. They can be extended to gas production or chemical raw material suppliers, adding new profit growth points. For example, high-purity carbon monoxide can be used to synthesize downstream high-value-added chemicals; high-purity hydrogen can be used in fuel cells or as clean energy; high-purity carbon dioxide can be used in the food industry or chemical raw materials; high-purity nitrogen is widely used in electronics, food and other industries. This technology significantly reduces the cost of hydrogen production and provides strong support for the development of the hydrogen energy economy. It is worth mentioning that the present invention is not only applicable to the steel industry, but may also be applied to other industrial fields, such as chemical industry, petrochemical industry, etc., with huge technical output and market potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 is a schematic diagram of a blast furnace gas membrane separation system in Example 1 of the present invention; Figure 2 This is a flow chart of the blast furnace gas membrane separation process in Example 1 of the present invention; Reference numerals: 1-pretreatment unit; 2-primary membrane separation unit; 3-first membrane separation unit; 4-first purification membrane separation unit; 5-first recovery unit; 6-second membrane separation unit; 7-second purification membrane separation unit; 8-third purification membrane separation unit; 9-second recovery unit 10- The third recovery unit; 11-first compressor; 12-first heat exchanger; 61-second compressor; 62-second heat exchanger; 41-third compressor; 42-third heat exchanger; 71-fourth compressor; 72-fourth heat exchanger; 81-fifth compressor; 82-fifth heat exchanger. DETAILED DESCRIPTION The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0039] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0040] This embodiment provides a blast furnace gas membrane separation process, in which the blast furnace gas treated by the pretreatment unit is passed into a primary membrane separation unit. After separation by the primary membrane assembly of the primary membrane separation unit, the blast furnace gas is separated into a first mixed gas and a second mixed gas, wherein the first mixed gas includes carbon monoxide and nitrogen, and the second mixed gas includes carbon dioxide and hydrogen.

[0041] The primary membrane separation unit comprises a primary membrane assembly, a first compressor and a first heat exchanger. The membrane of the primary membrane assembly has high selectivity for hydrogen and carbon dioxide, can block the first mixed gas on the interception side, and permeate the second mixed gas to the permeation side, thereby achieving separation of the first mixed gas and the second mixed gas.

[0042] The ratio of the permeability coefficients of the membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide is greater than or equal to 2. Preferably, the ratio of the permeability coefficients of the membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide is greater than or equal to 16.

[0043] Furthermore, after the first mixed gas is passed into the first membrane separation unit, nitrogen and carbon monoxide are separated. The first membrane separation unit includes a first membrane separation component, which has a strong selectivity for carbon monoxide and can block nitrogen at the interception side of the first membrane separation component, and carbon monoxide enters the permeation side through the first membrane separation component, thereby achieving separation of nitrogen and carbon monoxide.

[0044] The permeability coefficient ratio of the membrane in the first membrane separation component to carbon monoxide and nitrogen is greater than or equal to 10. Preferably, the permeability coefficient ratio of the membrane in the first membrane separation component to carbon monoxide and nitrogen is greater than or equal to 15.

[0045] Furthermore, the carbon monoxide concentrated on the permeate side of the first membrane separation component passes through the first purification membrane separation unit to purify the carbon monoxide. The first purification membrane separation unit includes a first purification membrane component, a second compressor and a second heat exchanger. The first purification membrane component has high selectivity for carbon monoxide. The carbon monoxide on the permeate side of the first membrane separation component passes through the first purification membrane component. The carbon monoxide permeates to the permeate side of the first purification membrane component, and other mixed gases are blocked on the interception side of the first purification membrane component. The mixed gas blocked on the interception side is recovered to the feed side of the first membrane separation component through the first recovery unit, and separated again to improve the recovery rate of carbon monoxide in blast furnace gas.

[0046] The ratio of the permeability coefficients of the membrane of the first purification membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 10. Preferably, the ratio of the permeability coefficients of the membrane of the first purification membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 15.

[0047] After the second mixed gas is passed into the second membrane separation unit, separation of hydrogen and carbon dioxide is achieved. The second membrane separation unit includes a second membrane separation component, a third compressor and a third heat exchanger. The membrane of the second membrane separation component has a strong high selectivity for hydrogen and can block carbon dioxide on the interception side of the second membrane separation component, while hydrogen enters the permeation side through the second membrane separation component, thereby separation of hydrogen and carbon dioxide is achieved.

[0048] The permeability coefficient ratio of the second membrane separation unit membrane to hydrogen and carbon dioxide is greater than or equal to 75. Preferably, the permeability coefficient ratio of the second membrane separation unit membrane to hydrogen and carbon dioxide is greater than or equal to 80.

[0049] Furthermore, the carbon dioxide blocked at the interception side of the second membrane separation component is introduced into the second purification membrane separation unit, which includes a second purification membrane separation component, a third compressor and a third heat exchanger. The membrane of the second purification membrane separation component has a strong selectivity for carbon dioxide, and can allow the concentrated carbon dioxide to enter the permeation side through the second purification membrane separation component, and block other mixed gases at the interception side. The mixed gas blocked at the interception side is recovered to the feed side of the first membrane separation unit through the second recovery unit, and is separated again, thereby improving the recovery rate of carbon monoxide in blast furnace gas.

[0050] The permeability ratio of the second purification membrane separation unit membrane to carbon dioxide and hydrogen is greater than or equal to 160. Preferably, the permeability ratio of the second purification membrane separation unit membrane to carbon dioxide and hydrogen is greater than or equal to 180.

[0051] Furthermore, the hydrogen on the permeate side of the second membrane separation assembly is purified by a third purification membrane separation unit, the third purification membrane separation unit includes a third purification membrane separation assembly, a fourth compressor and a fourth heat exchanger, the membrane of the third purification membrane separation assembly has a strong selectivity for hydrogen, when the hydrogen passes into the third purification membrane separation assembly, the hydrogen enters the permeate through the third purification membrane separation assembly, and the mixed gas is blocked on the interception side of the third purification membrane separation assembly, the mixed gas blocked on the interception side is recovered to the feed side of the second membrane separation unit through the third recovery unit, and separated again, thereby improving the recovery rate of hydrogen in the blast furnace gas.

[0052] The permeability coefficient ratio of the third purification membrane separation unit membrane to hydrogen and carbon dioxide is greater than or equal to 75. Preferably, the permeability coefficient ratio of the third purification membrane separation unit membrane to hydrogen and carbon dioxide is greater than or equal to 80.

[0053] Furthermore, the present embodiment provides a blast furnace gas membrane separation system, comprising a primary membrane separation unit, the primary membrane separation unit comprising a primary membrane assembly, the primary membrane assembly in the primary membrane separation unit separating the blast furnace gas into a first mixed gas and a second mixed gas, the first mixed gas comprising carbon monoxide and nitrogen, the second mixed gas comprising carbon dioxide and hydrogen, The embodiment of the present invention does not limit the membrane in the primary membrane assembly, as long as it can achieve preferential permeation of carbon dioxide and hydrogen. Preferably, the membrane in the primary membrane assembly can be at least one of a hollow fiber carbon membrane and a carbon molecular sieve membrane.

[0054] More preferably, a hollow fiber carbon membrane, named Cellulose carbon hollow fiber membrane, is the membrane of the primary membrane assembly (referenced from ACS Sustainable Chemistry & Engineering, 2024, 12(8):3344–3354, DOI: 10.1021 / acssuschemeng.3c08236), its permeability coefficient to CO2 is 8.5GPU, its permeability coefficient to N2 is 0.28GPU, its permeability coefficient to H2 is 20.3GPU, and its permeability coefficient to CO is 0.67GPU. Therefore, the selectivity of the hollow fiber carbon membrane to H2 and CO is 30.3, the selectivity to H2 and N2 is 72.5, and the selectivity to CO2 and CO is 12.7. Therefore, in the working process, when the hollow fiber carbon membrane is used as the membrane of the primary membrane assembly of the primary membrane separation unit, when the primary membrane assembly separates CO2 and H2 from CO and N2, the CO2 and H2 in the blast furnace gas enter the permeation test through the primary membrane assembly, while CO and N2 are blocked on the interception side of the membrane, effectively separating CO and N2 from CO2 and H2.

[0055] The primary membrane separation unit also includes a first compressor and a first heat exchanger, wherein the first compressor is used to control the pressure of the gas when passing through the primary membrane assembly, and the first heat exchanger is used to control the temperature of the gas when passing through the primary membrane assembly to ensure that the primary membrane assembly can fully exert its separation performance.

[0056] Exemplarily, the first compressor adjusts the pressure of the mixed gas entering the primary membrane module to 8 bar, and the first heat exchanger adjusts the temperature of the mixed gas entering the primary membrane module to 80°C.

[0057] The blast furnace gas membrane separation system also includes a first membrane separation unit connected to the primary membrane separation unit, the first membrane separation unit includes a first membrane separation assembly, and the first membrane separation assembly realizes gas separation according to the permeability of the membrane of the first membrane separation assembly to the gas to be separated.

[0058] For example, the membrane of the first membrane separation component can be a solid-state facilitated transport composite membrane, which has a strong permeability to carbon monoxide, such as PEGBEM-g-PMA (7:3) / AgBF4 / MgO-NS (referenced from Park CH, Lee JH, Kim NU, et al. Solid-state facilitated transport of carbon monoxide through mixed matrix membranes[J].Journal of MembraneScience, 2019, 592:117373-.DOI:10.1016 / j.memsci.2019.117373.), its permeability coefficient to CO2 is 6.6GPU, its permeability coefficient to N2 is 5.4GPU, its permeability coefficient to H2 is 8GPU, and its permeability coefficient to CO is 79GPU. Therefore, the selectivity of the membrane to CO and N2 is 14.7. Therefore, in the working process, when the solid-state facilitated transfer membrane is used to separate carbon monoxide and hydrogen in the first mixed gas, after the first mixed gas passes through the first membrane separation component, carbon monoxide and a small amount of mixed gas pass through the membrane into the permeation side, while nitrogen is blocked on the retention side, thereby achieving the separation of carbon monoxide and nitrogen. It should be noted that the nitrogen blocked on the retention side can meet the emission standards and can be directly discharged or utilized.

[0059] In some of the embodiments, a compressor, an expander and a heat exchanger may be added between the primary membrane unit and the first membrane separation unit according to the selected membrane. Preferably, the first membrane separation unit includes a first membrane separation component, a sixth compressor and a sixth heat exchanger.

[0060] In order to collect carbon monoxide with higher purity, an embodiment of the present invention is provided with a first purification membrane separation unit, which is connected to the first membrane separation unit. The first purification membrane separation unit includes a first purification membrane assembly. The membrane of the first purification membrane assembly can be made of the same material as the membrane of the first membrane separation assembly. During operation, carbon monoxide and a small amount of mixed gas pass through the first purification membrane assembly, and the high-purity carbon monoxide gas enters the permeate side, while the mixed gas is blocked on the interception side.

[0061] The first purification membrane separation unit also includes a second compressor and a second heat exchanger, wherein the second compressor is used to control the pressure of the gas when passing through the first purification membrane assembly, and the second heat exchanger is used to control the temperature of the gas when passing through the first purification membrane assembly to ensure that the first purification membrane assembly can fully exert its separation performance.

[0062] Exemplarily, the second compressor adjusts the pressure of the mixed gas when passing into the first purification membrane module to 8 bar, and the second heat exchanger adjusts the temperature of the mixed gas when passing into the first purification membrane module to 80°C.

[0063] In order to improve the capture rate of each gas in the blast furnace gas, the embodiment of the present invention is provided with a first recovery unit on the interception side of the first purification membrane assembly. The first recovery unit recovers the mixed gas on the interception side of the first purification membrane assembly to the feed side of the first membrane separation unit, thereby improving the capture rate of each gas in the blast furnace gas.

[0064] The blast furnace gas membrane separation system further comprises a second membrane separation unit connected to the primary membrane separation unit, wherein the second membrane separation unit comprises a second membrane separation assembly, and the second membrane separation assembly separates gases according to the permeability of the membrane of the second membrane separation assembly to the gas to be separated. For example, the membrane of the second membrane separation component can be a hollow fiber carbon membrane, which has a strong permeability to hydrogen, such as a membrane model CHFM-850 (referenced from the literature Nature Communications, 12, 268(2021). DOI:10.1038 / s41467-020-20628-9), its permeability coefficient to CO2 is 1.77GPU, its permeability coefficient to N2 is 0.185GPU, its permeability coefficient to H2 is 148.2GPU, and its permeability coefficient to CO is 0.19GPU. The selectivity of the membrane to H2 and CO2 is 83.9. Therefore, during the working process, when this type of membrane is used as the membrane of the second membrane separation component to separate the gas in the second mixed gas, hydrogen enters the permeation side through the second membrane separation component, and carbon dioxide is blocked on the retention side, thereby realizing the separation of carbon dioxide and hydrogen.

[0065] The second membrane separation unit also includes a third compressor and a third heat exchanger. The third compressor is used to control the pressure of the gas when passing through the second membrane separation assembly, and the second heat exchanger is used to control the temperature of the gas when passing through the second membrane separation assembly to ensure that the second membrane separation assembly can fully exert its separation performance.

[0066] Exemplarily, the third compressor adjusts the pressure of the mixed gas when entering the second membrane separation assembly to 8 bar, and the third heat exchanger adjusts the temperature of the mixed gas when entering the second membrane separation assembly to 130°C.

[0067] In order to further obtain carbon dioxide gas with higher purity, the embodiment of the present invention further provides a second purification membrane separation unit, which is connected to the first membrane separation unit and is used to further purify the carbon dioxide on the interception side of the first membrane separation component. The second purification membrane separation unit includes a second purification membrane component, and the membrane of the second purification membrane component has a strong permeability to carbon dioxide.

[0068] Exemplarily, the membrane of the second purification membrane assembly can be a facilitated transport composite membrane, for example, a membrane with a model number of PVP-co-PVAc / MWNTs, which has a permeability coefficient of 1451GPU for CO2, a permeability coefficient of 8.879GPU for N2, a permeability coefficient of 8.83GPU for H2, and a permeability coefficient of 100GPU for CO, and the selectivity of the membrane to CO2 and N2 is 165. Therefore, when the membrane with a model number of PVP-co-PVAc / MWNTs is used as the membrane of the second purification membrane assembly, during operation, the carbon dioxide on the retention side of the first membrane separation assembly is passed into the second purification membrane assembly, and the carbon dioxide enters the permeation side through the second purification membrane assembly, while other mixed gases are blocked on the retention side, thereby achieving purification of the carbon dioxide.

[0069] The second purification membrane unit further includes a fourth compressor and a fourth heat exchanger. The fourth compressor is used to control the pressure of the gas when passing through the second purification membrane module, and the fourth heat exchanger is used to control the temperature of the gas when passing through the second purification membrane module to ensure that the second purification membrane module can fully exert its separation performance.

[0070] Exemplarily, the fourth compressor adjusts the pressure of the mixed gas when entering the second purification membrane module to 4 bar, and the fourth heat exchanger adjusts the temperature of the mixed gas when entering the second purification membrane module to 67°C.

[0071] In order to improve the capture rate of each gas in the blast furnace gas, the embodiment of the present invention is provided with a second recovery unit on the interception side of the second purification membrane assembly. The second recovery unit recovers the mixed gas on the interception side of the second purification membrane assembly to the feed side of the first membrane separation unit, thereby improving the capture rate of each gas in the blast furnace gas.

[0072] In order to further obtain hydrogen gas with higher purity, the embodiment of the present invention further provides a third purification membrane separation unit, which is connected to the second membrane separation unit and is used to further purify the hydrogen on the permeation side of the first membrane separation component. The third purification membrane separation unit includes a third purification membrane component, and the membrane of the third purification membrane component has a strong permeability to hydrogen.

[0073] Specifically, the membrane of the third purification membrane assembly may be a hollow fiber carbon membrane. More specifically, the membrane of the third purification membrane assembly in the embodiment of the present invention may be the same as or different from the membrane of the second membrane separation assembly.

[0074] The third purification membrane unit further includes a fifth compressor and a fifth heat exchanger. The fifth compressor is used to control the pressure of the gas when passing through the third purification membrane module, and the fifth heat exchanger is used to control the temperature of the gas when passing through the third purification membrane module to ensure that the third purification membrane module can fully exert its separation performance.

[0075] Exemplarily, the fifth compressor adjusts the pressure of the mixed gas when passing through the third purification membrane module to 8 bar, and the fifth heat exchanger adjusts the temperature of the mixed gas when passing through the third purification membrane module to 130°C.

[0076] In order to improve the capture rate of each gas in the blast furnace gas, the embodiment of the present invention is provided with a third recovery unit on the interception side of the third purification membrane assembly. The third recovery unit recovers the mixed gas on the interception side of the third purification membrane assembly to the feed side of the second membrane separation unit, thereby improving the capture rate of each gas in the blast furnace gas.

[0077] In order to ensure that the blast furnace gas entering the membrane system is clean and dry and prevent membrane pollution, the blast furnace gas membrane separation system provided in an embodiment of the present invention also includes a pretreatment unit, which includes a desulfurization module, a filtration module and a dehumidification module. The blast furnace gas enters the primary membrane separation unit after being treated by the pretreatment unit.

[0078] Among them, the main function of the desulfurization module is to remove sulfides from blast furnace gas to prevent it from corroding and polluting the membrane system. The filtration module is responsible for removing particulate matter and impurities in blast furnace gas, thereby protecting the normal operation of the membrane separation device. The dehumidification module removes moisture from blast furnace gas through technologies such as condensation and adsorption to avoid the impact of excessive humidity on membrane separation efficiency. The module setting of the pretreatment unit can be adjusted accordingly according to the selection of subsequent membranes. Different membranes have different requirements for humidity and impurities in blast furnace gas. Therefore, the design and optimization of the pretreatment unit are crucial to ensure the efficient and stable operation of the membrane separation system. Through reasonable pretreatment, the negative impact on the subsequent membrane separation unit can be reduced, thereby ensuring that the membrane separation system maintains efficient separation capabilities during long-term operation.

[0079] Example 1 See also Figure 1 As shown, this embodiment provides a blast furnace gas membrane separation system, and the specific structure and membrane material are as follows: The blast furnace gas membrane separation system comprises a pretreatment unit 1 , a primary membrane separation unit 2 , a first membrane separation unit 3 , a second membrane separation unit 6 , a first purification membrane separation unit 4 , a second purification membrane separation unit 7 and a third purification membrane separation unit 8 .

[0080] The pretreatment unit includes a desulfurization module, a filtration module and a dehumidification module.

[0081] The primary membrane separation unit comprises a primary membrane assembly, the membrane in the primary membrane assembly is a hollow fiber carbon membrane, specifically named Cellulose carbon hollow fiber membrane, and the primary membrane separation unit further comprises a first compressor and a first heat exchanger.

[0082] The first membrane separation unit is connected to the primary membrane separation unit, and the first membrane separation unit includes a first membrane separation assembly. The membrane of the first membrane separation assembly can be a solid-state facilitated transfer composite membrane, and the specific membrane name is PEGBEM-g-PMA (7:3) / AgBF4 / MgO-NS.

[0083] The first purification membrane separation unit is connected to the first membrane separation unit, the first purification membrane separation unit includes a first purification membrane assembly, the membrane of the first purification membrane assembly can be made of the same material as the membrane of the first membrane separation assembly, and the first purification membrane separation unit also includes a second compressor and a second heat exchanger.

[0084] In this embodiment, a first recovery unit 5 is connected to the first purification membrane separation unit. The first recovery unit recovers the mixed gas on the interception side of the first purification membrane separation unit to the feed side of the first membrane separation unit.

[0085] The primary membrane separation unit is also connected to a second membrane separation unit, which includes a second membrane separation component, a third compressor and a third heat exchanger. The membrane of the second membrane separation component is a hollow fiber carbon membrane, and the name of the membrane is CHFM-850 membrane.

[0086] The second purification membrane separation unit is connected to the second membrane separation unit, and the second purification membrane separation unit includes a second purification membrane assembly, a fourth compressor and a fourth heat exchanger. The membrane of the second purification membrane assembly is a facilitated transfer composite membrane, and the name of the membrane is a PVP-co-PVAc / MWNTs membrane.

[0087] The second purification membrane separation unit is also connected to a second recovery unit 9, which recovers the mixed gas on the interception side of the second purification membrane module to the feed side of the first membrane separation unit.

[0088] The third purification membrane separation unit is connected to the second membrane separation unit, and the third purification membrane separation unit comprises a third purification membrane assembly, a fifth compressor and a fifth heat exchanger. The membrane of the third purification membrane assembly is a hollow fiber carbon membrane, and the name of the membrane is CHFM-850 membrane.

[0089] In this embodiment, a third recovery unit 10 is connected to the third purification membrane separation unit, and the third recovery unit recovers the mixed gas on the interception side of the third purification membrane module to the feed side of the second membrane separation unit.

[0090] Using the above-mentioned blast furnace gas membrane separation system, this embodiment provides a blast furnace gas membrane separation process, see Figure 2 The specific steps are as follows: In this embodiment, the blast furnace gas treated by the pretreatment unit includes 16 vol% CO2, 26 vol% CO, 3 vol% H2, and 55 vol% N2, and the pretreated blast furnace gas is passed into the primary membrane separation unit 2.

[0091] The first compressor 11 adjusts the pressure of the mixed gas entering the primary membrane assembly to 8 bar, and the first heat exchanger 12 adjusts the temperature of the mixed gas entering the primary membrane assembly to 80° C. A hollow fiber carbon membrane is used as the membrane of the primary membrane assembly of the primary membrane separation unit 2. CO2 and H2 in the blast furnace gas enter the permeate side through the primary membrane assembly to form a second mixed gas, while CO and N2 are blocked on the interception side of the membrane to form a first mixed gas, effectively separating CO and N2 from CO2 and H2.

[0092] The first mixed gas separated by the primary membrane separation unit enters the first membrane separation unit 3 for separation. The first mixed gas on the feed side of the first membrane separation unit includes 1.85 vol% CO2, 40.9 vol% CO, 0.2 vol% H2, and 57.1 vol% N2.

[0093] The solid-state facilitated transfer composite membrane is used as the membrane of the first membrane separation component. After the first mixed gas passes through the first membrane separation component, carbon monoxide and a small amount of mixed gas pass through the membrane into the permeation side, while nitrogen is blocked on the retention side, thereby achieving the separation of carbon monoxide and nitrogen. It should be noted that the content of nitrogen blocked on the retention side is 93.19 vol%, which meets the emission standards and can be directly discharged or utilized.

[0094] The carbon monoxide and a small amount of mixed gas separated by the first membrane separation unit enter the first purification membrane separation unit 4 for separation. The carbon monoxide and a small amount of mixed gas on the feed side of the first purification membrane separation unit include 0.9 vol% CO2, 75.5 vol% CO, 0.1 vol% H2, and 23.5 vol% N2.

[0095] The second compressor 61 adjusts the pressure of the mixed gas when passing into the first purification membrane module to 8 bar, and the second heat exchanger 62 adjusts the temperature of the mixed gas when passing into the first purification membrane module to 80°C. The carbon monoxide on the permeate side of the first membrane separation module and a small amount of mixed gas pass through the first purification membrane separation unit, and the carbon monoxide gas enters the permeate side of the first purification membrane module, while the mixed gas is blocked on the interception side.

[0096] The mixed gas blocked on the retentate side of the first purification membrane module is recovered to the feed side of the first membrane separation unit via the first recovery unit 5 and separated repeatedly.

[0097] The second mixed gas after separation by the primary membrane separation unit enters the second membrane separation unit 6 for separation. The second mixed gas on the feed side of the second membrane separation unit includes 51.5 vol% CO2, 17.2 vol% CO, 14.9 vol% H2, and 16.4 vol% N2.

[0098] The third compressor 41 adjusts the pressure of the mixed gas when entering the second membrane separation component to 8 bar, and the third heat exchanger 42 adjusts the temperature of the mixed gas when entering the second membrane separation component to 130°C, and the second mixed gas is passed into the second membrane separation unit for separation, with a hollow fiber carbon membrane named CHFM-850 as the membrane of the second membrane separation component. The hydrogen of the second mixed gas passes through the second membrane separation component into the permeation side, and the carbon dioxide is blocked on the retention side, thereby achieving the separation of carbon dioxide and hydrogen.

[0099] The gas separated by the second membrane separation unit enters the second purification membrane separation unit 7 and the third purification membrane separation unit 8 for separation, wherein the gas on the feed side of the second purification membrane separation unit includes 58.6 vol% CO2, 20.6 vol% CO, 1.2 vol% H2, and 19.6 vol% N2, and the gas on the feed side of the third purification membrane separation unit includes 16.6 vol% CO2, 0.6 vol% CO, 82.2 vol% H2, and 0.6 vol% N2.

[0100] The fourth compressor 71 adjusts the pressure of the mixed gas when passing into the second purification membrane assembly to 4 bar, and the fourth heat exchanger 72 adjusts the temperature of the mixed gas when passing into the second purification membrane assembly to 67°C, and passes the carbon dioxide on the retention side of the second membrane separation assembly into the second purification membrane separation unit to promote the transfer of the composite membrane. When the membrane named PVP-co-PVAc / MWNTs is the second purification membrane separation component, carbon dioxide can enter the permeation side, while other mixed gases are blocked on the retention side, thereby achieving the purification of carbon dioxide. The mixed gas on the retention side of the second purification membrane separation assembly is recovered to the feed side of the first membrane separation unit through the second recovery unit 9.

[0101] The gas permeated by the second membrane separation module is injected into the third purification membrane separation unit from the feed side of the third purification membrane separation unit. The fifth compressor 81 adjusts the pressure of the mixed gas when passing into the third purification membrane module to 8 bar. The fifth heat exchanger 82 adjusts the temperature of the mixed gas when passing into the third purification membrane module to 130°C. The hollow fiber carbon membrane, named CHFM-850, is used as the membrane of the third purification membrane assembly, which can allow hydrogen in the mixed gas to enter the permeation side through the third purification membrane assembly, while blocking the mixed gas on the interception side. The mixed gas is recovered to the feed side of the second membrane separation unit through the third recovery unit 10 and separated again.

[0102] The purity of CO2 separated by the blast furnace gas membrane separation process of this embodiment is 95.0vol%, the purity of CO is 97.0vol%, the purity of H2 is 99.6vol%, and the purity of N2 is 93.2vol%. The capture rates of CO2, CO and H2 can all reach more than 90vol%, and the energy consumption of this embodiment is 0.1kWh / m³.

[0103] Example 2 This embodiment provides a blast furnace gas membrane separation system, the specific structure and membrane material are the same as those of Example 1, the difference is that the permeability coefficient ratio of the membrane of the primary membrane assembly in the primary membrane separation unit to carbon dioxide and carbon monoxide is 12.

[0104] The purity of CO2, CO, H2 and N2 separated by the blast furnace gas membrane separation process of this embodiment is 94.5 vol%, 96.8 vol%, 98.8 vol% and 92.7 vol%, respectively. The capture rates of CO2, CO and H2 can all reach more than 90 vol%. The total membrane area of ​​this embodiment is 3816614 m 2 , the system energy consumption is 126730kWh.

[0105] Example 3 This embodiment provides a blast furnace gas membrane separation system, the specific structure and membrane material are the same as those of Example 1, the difference is that the permeability coefficient ratio of the membrane of the primary membrane assembly in the primary membrane separation unit to carbon dioxide and carbon monoxide is 5.

[0106] The purity of CO2, CO, H2 and N2 separated by the blast furnace gas membrane separation process of this embodiment is 94.5 vol%, 97.1 vol%, 99.0 vol% and 93.0 vol%, respectively. The capture rates of CO2, CO and H2 can all reach more than 90 vol%. The total membrane area of ​​this embodiment is 3706580 m 2 , the system energy consumption is 140212kWh.

[0107] Example 4 This embodiment provides a blast furnace gas membrane separation system, the specific structure and membrane material are the same as those of Example 1, the difference is that the permeability coefficient ratio of the membrane of the primary membrane assembly in the primary membrane separation unit to carbon dioxide and carbon monoxide is 2.

[0108] The purity of CO2, CO, H2 and N2 separated by the blast furnace gas membrane separation process of this embodiment is 94.5 vol%, 96.5 vol%, 97.8 vol% and 91.2 vol%, respectively. The capture rates of CO2, CO and H2 can all reach more than 90 vol%. The total membrane area of ​​this embodiment is 3703803m 2 , the system energy consumption is 168198kWh.

[0109] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A blast furnace gas membrane separation process, It is characterized in that The following steps are included: The blast furnace gas is introduced into a primary membrane separation unit to be separated into a first mixed gas and a second mixed gas, wherein the first mixed gas includes carbon monoxide and nitrogen, and the second mixed gas includes carbon dioxide and hydrogen, and the permeability coefficient ratio of the membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide is greater than or equal to 2, The first mixed gas is introduced into a first membrane separation unit to be separated into a mixed gas containing nitrogen and a mixed gas containing carbon monoxide, wherein the ratio of the permeability coefficient of the membrane in the first membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 10, The second mixed gas is introduced into the second membrane separation unit to be separated into a mixed gas containing carbon dioxide and a mixed gas containing hydrogen. The permeability coefficient ratio of the membrane in the second membrane separation unit to hydrogen and carbon dioxide is greater than or equal to 75.

2. The blast furnace gas membrane separation process according to claim 1, It is characterized in that The blast furnace gas membrane separation process further comprises passing the concentrated carbon monoxide-containing mixed gas into a first purification membrane separation unit for purification to obtain carbon monoxide, wherein the ratio of the permeability coefficient of the membrane in the first purification membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 10; and / or, Passing the concentrated carbon dioxide-containing mixed gas into a second purification membrane separation unit for purification to obtain carbon dioxide, wherein the ratio of the permeability coefficients of the membrane in the second purification membrane separation unit to carbon dioxide and hydrogen is greater than or equal to 160; and / or, The concentrated hydrogen-containing mixed gas is passed into a third purification membrane separation unit for purification to obtain hydrogen. The permeability coefficient ratio of the third purification membrane separation unit membrane to hydrogen and carbon dioxide is greater than or equal to 75.

3. The blast furnace gas membrane separation process according to claim 2, It is characterized in that The ratio of the permeability coefficients of the membrane in the primary membrane separation unit to carbon dioxide and carbon monoxide is greater than or equal to 16; and / or, The permeability coefficient ratio of the first membrane separation unit membrane to carbon monoxide and nitrogen is greater than or equal to 15; and / or, The permeability coefficient ratio of the second membrane separation unit membrane to hydrogen and carbon dioxide is greater than or equal to 80; and / or, The ratio of the permeability coefficients of the membrane of the first purification membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 15; and / or, The permeability coefficient ratio of the second purification membrane separation unit membrane to carbon dioxide and hydrogen is greater than or equal to 180; and / or, The permeability coefficient ratio of the third purification membrane separation unit membrane to hydrogen and carbon dioxide is greater than or equal to 80.

4. The blast furnace gas membrane separation process according to claim 3, It is characterized in that The membrane in the primary membrane separation unit is at least one of a hollow fiber carbon membrane and a carbon dioxide selective membrane; and / or, The membrane in the first membrane separation unit is at least one of a solid facilitated transport composite membrane and a carbon monoxide selective membrane; and / or, The membrane in the second membrane separation unit is at least one of a hollow fiber carbon membrane and a hydrogen selective membrane; and / or, The membrane of the first purification membrane separation unit is at least one of a solid facilitated transport composite membrane, a carbon monoxide selective membrane, and a nitrogen selective membrane; and / or, The membrane of the second purification membrane separation unit is at least one of a facilitated transport composite membrane, a carbon dioxide selective membrane or a hydrogen selective membrane; and / or, The membrane of the third purification membrane separation unit is at least one of a hollow fiber carbon membrane, a hydrogen selective membrane or a carbon dioxide selective membrane.

5. The blast furnace gas membrane separation process according to claim 4, It is characterized in that The gas pressure introduced into the primary membrane separation unit is 2-20 bar, and the gas temperature is 25-200° C.; and / or, The gas pressure introduced into the first membrane separation unit is 2-10 bar, and the gas temperature is 25-80° C.; and / or, The gas pressure introduced into the second membrane separation unit is 2-20 bar, and the gas temperature is 25-200° C.; and / or, The gas pressure introduced into the first purification membrane separation unit is 2-10 bar, and the gas temperature is 25-80° C.; and / or, The gas pressure introduced into the second purification membrane separation unit is 2-5 bar, and the gas temperature is 25-80° C.; and / or, The gas pressure introduced into the third purification membrane separation unit is 2-20 bar, and the gas temperature is 25-200°C.

6. The blast furnace gas membrane separation process according to any one of claims 1 to 5, It is characterized in that The method further comprises the step of recycling the unpurified mixed gas to the first membrane separation unit and / or the second membrane separation unit.

7. A blast furnace gas membrane separation system, It is characterized in that Adopting the blast furnace gas membrane separation process according to any one of claims 1 to 6; The membrane separation system comprises a primary membrane separation unit, a first membrane separation unit connected to the primary membrane separation unit and a second membrane separation unit. The primary membrane separation unit is used to separate blast furnace gas into a first mixed gas and a second mixed gas, wherein the first mixed gas includes carbon monoxide and nitrogen, and the second mixed gas includes carbon dioxide and hydrogen, and the permeability coefficient ratio of the membrane of the primary membrane separation unit to carbon dioxide and carbon monoxide is greater than or equal to 2, The first membrane separation unit is used to separate the first mixed gas into a mixed gas containing nitrogen and a mixed gas containing carbon monoxide, and the permeability coefficient ratio of the membrane in the first membrane separation unit to carbon monoxide and nitrogen is greater than or equal to 10. The second membrane separation unit is used to separate the second mixed gas into a mixed gas containing carbon dioxide and a mixed gas containing hydrogen. The permeability coefficient ratio of the membrane in the second membrane separation unit to hydrogen and carbon dioxide is greater than or equal to 75.

8. The blast furnace gas membrane separation system according to claim 7, It is characterized in that The first membrane separation unit is connected to a first purification membrane separation unit; and / or, The second membrane separation unit is connected to a second purification membrane separation unit; and / or, The second membrane separation unit is connected to a third purification membrane separation unit.

9. The blast furnace gas membrane separation system according to claim 8, It is characterized in that The primary membrane separation unit comprises a primary membrane separation assembly, a first compressor and a first heat exchanger; and / or, The first membrane separation unit comprises a first membrane separation assembly; and / or, The second membrane separation unit comprises a second membrane separation assembly, a second compressor and a second heat exchanger; and / or, The first purification membrane separation unit comprises a first purification membrane separation assembly, a third compressor and a third heat exchanger; and / or, The second purification membrane separation unit comprises a second purification membrane separation assembly, a fourth compressor and a fourth heat exchanger; and / or, The third purification membrane separation unit includes a third purification membrane separation assembly, a fifth compressor and a fifth heat exchanger.

10. The blast furnace gas membrane separation system according to claim 9, It is characterized in that The blast furnace gas membrane separation system further comprises a first recovery unit, a second recovery unit and a third recovery unit. The first recovery unit is connected to the first purification membrane separation unit and is used to recover the mixed gas intercepted by the first purification membrane separation unit to the first membrane separation unit. The second recovery unit is connected to the second purification membrane separation unit and is used to recover the mixed gas intercepted by the second purification membrane separation unit to the first membrane separation unit. The third recovery unit is connected to the third purification membrane separation unit and is used to recover the mixed gas intercepted by the third purification membrane separation unit to the second membrane separation unit; and / or, The first membrane separation unit further includes a sixth compressor and a sixth heat exchanger.

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