A high-temperature electrochemical hydrogen pump and water-gas shift conversion system and method for producing hydrogen from H2 / CO byproduct gas with wide concentrations

Abstract

A wide-concentration hydrogen production system and method integrating a high-temperature electrochemical hydrogen pump and water-gas shift reaction, belonging to the field of chemical technology, improves the hydrogen yield and fuel gas calorific value of the hydrogen production process from H2 / CO-containing by-product gas by means of gas membrane separation, pressure swing adsorption, and high-temperature electrochemical hydrogen pump separation technologies in different advantageous hydrogen separation ranges, and enhances the coupling of the water-gas shift reaction. The system of this invention features a "one-click adjustment" operation mode based on the hydrogen content of the by-product gas, strengthens the recovery of desorbed gas from pressure swing adsorption, and stably and economically produces fuel cell hydrogen under a wide range of raw material hydrogen and carbon monoxide concentrations, while producing high-calorific-value fuel gas as a by-product. It fundamentally avoids key problems that restrict the improvement of hydrogen yield, such as the difficulty in utilizing CO components in the by-product gas, the low hydrogen concentration in the desorbed gas from the pressure swing adsorption unit, and the difficulty in fully recovering hydrogen from the membrane separation permeate. This system meets the market demand for high-quality fuel cell hydrogen and high-calorific-value fuel gas while minimizing operating costs and overall energy consumption.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology. It improves the hydrogen yield and fuel gas calorific value in hydrogen production processes using H2 / CO byproduct gas through the cascaded integration of gas membrane separation, pressure swing adsorption (PSA), and high-temperature electrochemical hydrogen pump separation technologies across different advantageous hydrogen separation ranges, coupled with the water-gas shift reaction. The system features a "one-click adjustment" operating mode based on the hydrogen content of the byproduct gas, enhancing the recovery of desorbed gas from PSA. This allows for stable and economical production of fuel cell hydrogen under a wide range of raw material hydrogen and carbon monoxide concentrations, while also producing high-calorific-value fuel gas as a byproduct. The system proposed in this invention fundamentally avoids key problems that hinder hydrogen yield improvement, such as the difficulty in utilizing CO components in the byproduct gas, the low hydrogen concentration in the desorbed gas from the PSA unit, and the difficulty in fully recovering hydrogen from the membrane separation permeate. It meets the market demand for high-quality fuel cell hydrogen and high-calorific-value fuel gas while minimizing operating costs and overall energy consumption. Background Technology

[0002] The production of hydrogen for fuel cells is a prerequisite for realizing the future "hydrogen economy." Currently, my country's hydrogen mainly comes from fossil fuel-derived hydrogen ("grey hydrogen") and industrial by-product hydrogen. H2 / CO-containing by-product gases are widely present in fossil fuel processing, with a huge annual output. Due to differences in fossil fuels and process conditions used in different plants, their hydrogen concentration is generally higher than 20 vol%, and carbon monoxide concentration is higher than 2 vol%, making them a highly promising hydrogen production feedstock. Therefore, utilizing H2 / CO-containing by-product gases to produce fuel cell-grade high-purity hydrogen is of great significance for improving resource utilization efficiency and reducing hydrogen production costs in my country's petrochemical and coal chemical industries. Currently, the mainstream technologies for extracting hydrogen from by-product gases mainly include cryogenic separation, pressure swing adsorption (PSA), and membrane separation. Among these, cryogenic separation is energy-intensive, complex to operate, and the purity of the hydrogen obtained is usually difficult to meet the standards for fuel cell hydrogen (H2 concentration ≥ 99.97 vol%, CO concentration < 0.2 ppm, CO2 concentration < 2 ppm). While pressure swing adsorption (PSA) can produce high-purity hydrogen, the presence of CO, a difficult-to-desorb component in the by-product gas, generally results in a low hydrogen recovery rate (around 75%). A significant amount of hydrogen remains unrecovered in the desorption tail gas, often being used directly as fuel gas, leading to low-value utilization of hydrogen. Membrane separation alone offers advantages such as simple operation, low energy consumption, and high recovery rate. However, its separation selectivity is limited by the membrane material, making it difficult to obtain high-purity hydrogen in one step. Furthermore, the content of impurities such as CO and CO2 in the hydrogen product is often difficult to meet standards. Therefore, membrane separation is often coupled with PSA. First, membrane separation is used to concentrate hydrogen from low-hydrogen gases such as by-product gas or PSA desorption gas. Then, the concentrated gas is fed into the PSA unit to produce high-purity hydrogen. This combined approach achieves high recovery rate and high-purity hydrogen recovery.

[0003] High-temperature electrochemical hydrogen pumps are a novel hydrogen separation technology that enables the efficient recovery of low-hydrogen, CO-containing gases (H2 < 30.0 vol%; CO < 5.0 vol%), with an H2 recovery rate exceeding 99%. High-purity (≥ 99.97 vol%) pressurized hydrogen is obtained at the cathode. Due to the high operating temperature (>150℃) of the high-temperature polybenzimidazole proton exchange membrane used, the adsorption and poisoning effects of CO on the electrodes can be suppressed. This provides a new solution for the resource utilization of low-concentration hydrogen-containing gases containing CO generated in membrane and pressure swing adsorption units during by-product gas hydrogen extraction processes. The proposed solution achieves one-step purification and pressurization of CO-containing low-hydrogen gas, thereby saving on compressor investment and operating costs in the hydrogen production system. However, due to the high CO content in the by-product gas (CO > 2.0 vol%) and the enrichment of CO during subsequent purification, directly using a high-temperature electrochemical hydrogen pump to purify hydrogen from the H2 / CO-containing by-product gas can lead to severe electrode poisoning, resulting in low operating current density and hydrogen permeation, affecting the hydrogen separation performance of the high-temperature electrochemical hydrogen pump. Therefore, it is necessary to convert the CO component in the hydrogen extraction process to reduce its impact on the membrane electrode of the high-temperature electrochemical hydrogen pump. Furthermore, CO is a potential hydrogen production component that can be obtained through a water-gas shift reaction, a simple process with mild reaction conditions. Converting CO can effectively increase hydrogen production and improve the operating conditions of the high-temperature electrochemical hydrogen pump, enabling efficient recovery of low-hydrogen CO-containing gas and fundamentally improving the hydrogen yield in the H2 / CO-containing by-product gas hydrogen production process.

[0004] In summary, this invention proposes a wide-concentration hydrogen production system for H2 / CO byproduct gas containing a high-temperature electrochemical hydrogen pump and a water-gas shift converter, which can simultaneously and efficiently produce hydrogen from wide-concentration byproduct gas, fuel cell hydrogen at carbon monoxide concentrations, and high-calorific-value fuel gas. The system utilizes a hydrogen membrane to concentrate hydrogen from the feedstock, followed by pressure swing adsorption (PSA) for high-purity hydrogen. A PSA is used to convert CO in the permeate side of the hydrogen membrane, increasing hydrogen production. Finally, the high-temperature electrochemical hydrogen pump purifies the PSA-desorbed hydrogen and the PSA gas, producing fuel cell hydrogen at the cathode. The remaining gas at the anode is decarbonized and dehydrated to obtain high-calorific-value fuel gas, maximizing hydrogen production to enhance the economic advantages of the H2 / CO byproduct gas hydrogen production process. Summary of the Invention

[0005] The purpose of this invention is to provide a wide-concentration hydrogen production system for H2 / CO byproduct gas containing a high-temperature electrochemical hydrogen pump and a water-gas shift reaction. This system leverages the separation advantages of different hydrogen separation units within their preferred hydrogen concentration ranges, and utilizes the water-gas shift reaction to convert CO into hydrogen, thereby increasing hydrogen production. The high-temperature electrochemical hydrogen pump then separates high-purity hydrogen from the low-hydrogen CO-containing gas and performs simultaneous compression, improving the hydrogen yield in the byproduct gas hydrogen production process and reducing compression energy consumption. To achieve the above objectives, the technical solution of this invention is as follows: A high-temperature electrochemical hydrogen pump and water-gas conversion integrated wide-concentration H2 / CO by-product gas hydrogen production system, the hydrogen production system including a hydrogen-rich separation unit, a low-hydrogen separation unit, a fuel gas treatment unit, and a water-gas conversion unit; The hydrogen production system includes a hydrogen-rich separation unit, a low-hydrogen separation unit, a fuel gas processing unit, and a water-gas conversion unit. In the hydrogen-rich separation unit, the H2 / CO by-product gas feedstock is compressed, membrane separated and pressure swing adsorption processes to concentrate hydrogen from the hydrogen-containing by-product gas and produce high-purity hydrogen product gas; at the same time, hydrogen-containing desorption gas and low-hydrogen permeate gas are generated for subsequent unit processing. The low-hydrogen separation unit uses high-temperature electrochemical hydrogen pump technology to purify low-hydrogen gas, further recover hydrogen gas and produce high-purity hydrogen; the anode outlet gas of the high-temperature electrochemical hydrogen pump is used as fuel gas product. The water-gas shift unit utilizes a water-gas shift reactor to react low-hydrogen permeate gas containing a high concentration of carbon monoxide with water vapor, converting it into hydrogen. Simultaneously, a heat exchanger recovers the heat from the reaction products, achieving gas composition adjustment and thermal energy utilization. The fuel gas processing unit cools, separates, and removes carbon dioxide from the gas from upstream to obtain a high-calorific-value fuel gas product that meets the requirements; and separates free water and carbon dioxide and discharges them from the system.

[0006] The hydrogen-rich separation unit includes a first compressor K-1, a second compressor K-2, a third compressor K-3, a first hydrogen membrane HM-1, a second hydrogen membrane HM-2, and a pressure swing adsorption (PSA) tower. The inlet of the first compressor K-1 is connected to the H2 / CO byproduct gas 1-1, and its outlet is connected to the inlet side of the first hydrogen membrane HM-1, supplying pressurized byproduct gas 1-2 to the first hydrogen membrane HM-1. The concentrated hydrogen outlet on the permeate side of the first hydrogen membrane HM-1 is connected to the inlet of the first mixer MIX-1, supplying first hydrogen membrane permeate gas 1-3 to the first mixer MIX-1. The inlet of the first mixer MIX-1 is also connected to the concentrated hydrogen outlet on the permeate side of the second hydrogen membrane HM-2, which supplies second hydrogen membrane permeate gas 1-9 to the first mixer MIX-1. The second hydrogen membrane HM-2 and the first mixer... A third control valve V-3 is installed between MIX-1; the outlet of the first mixer MIX-1 is connected to the inlet of the second compressor K-2, providing the second compressor K-2 with membrane separation mixed permeate gas 1-4; the outlet of the second compressor K-2 is connected to the inlet of the pressure swing adsorption tower PSA, providing the pressure swing adsorption tower PSA with pressurized hydrogen-rich permeate gas 1-5; the high-purity hydrogen H1-1 at the top of the pressure swing adsorption tower is separated from the high-purity hydrogen H1-2 output from the first electrochemical hydrogen pump EHP-1 and the high-purity hydrogen H1-2 output from the second electrochemical hydrogen pump EHP-2 in the low-hydrogen separation unit. The high-purity hydrogen H1-3 at the cathode of the electrochemical hydrogen pump is mixed and then sent out of the system as fuel cell hydrogen product H1-4. The PSA desorption gas outlet of the pressure swing adsorption tower is connected to the inlet of the third compressor K-3 via the first three-way valve S-1 and the first control valve V-1, which is used to supply the PSA desorption gas 1-6 to the third compressor K-3. The PSA desorption gas 1-6 is divided into two paths via the first three-way valve S-1. One path is connected to the third compressor K-3 via the first control valve V-1, and the other path is connected to the anode of the second electrochemical hydrogen pump EHP-2 via the second control valve V-2. The outlet of the third compressor K-3 is connected to the inlet of the second hydrogen membrane HM-2, supplying pressurized hydrogen-rich desorption gas 1-8 to the second hydrogen membrane HM-2; the outlet of the second hydrogen membrane HM-2 on the permeate side is connected to the second mixer MIX-2 via the fourth control valve V-4, for supplying the second hydrogen membrane low-hydrogen permeate gas 2-2 to the second mixer MIX-2, so that the second hydrogen membrane low-hydrogen permeate gas 2-2 enters the low-hydrogen separation unit; the outlet of the first hydrogen membrane HM-1 on the permeate side is connected to the inlet of the water-gas shift reactor WGS, supplying the first hydrogen membrane high-CO low-hydrogen permeate gas 3-1 to the water-gas shift reactor WGS, so that the first hydrogen membrane high-CO low-hydrogen permeate gas 3-1 enters the water-gas shift unit.

[0007] The low-hydrogen separation unit includes a first electrochemical hydrogen pump EHP-1 and a second electrochemical hydrogen pump EHP-2; the low-hydrogen permeate gas 2-2 from the second hydrogen membrane of the hydrogen-rich separation unit and the cooled shift gas 3-5 from the water-gas shift unit are mixed by the second mixer MIX-2 to obtain the anode inlet gas 2-3 of the first electrochemical hydrogen pump; the outlet of the second mixer MIX-2 is connected to the anode inlet side of the first electrochemical hydrogen pump EHP-1, supplying the anode inlet gas 2-3 of the first electrochemical hydrogen pump EHP-1; the first The anode outlet of the electrochemical hydrogen pump is connected to the inlet of the second heat exchanger E-2 of the fuel gas treatment unit, supplying the anode outlet gas F1-1 of the first electrochemical hydrogen pump to the second heat exchanger E-2; the pressure swing adsorption desorption gas 1-6 from the hydrogen-rich separation unit is connected to the anode inlet of the second electrochemical hydrogen pump EHP-2 via the first three-way valve S-1 and the second control valve V-2; the anode outlet gas of the second electrochemical hydrogen pump EHP-2 is mixed with the de-CO2 fuel gas F1-4 from the fuel gas treatment unit and then leaves the system as fuel gas product F1-5.

[0008] The water-gas shift unit includes a water-gas shift reactor (WGS) and a first heat exchanger (E-1). The inlet of the water-gas shift reactor (WGS) is also connected to medium-pressure steam (3-2), and the outlet is connected to the inlet of the second mixer (MIX-2) via the first heat exchanger (E-1). The high-CO, low-hydrogen permeate gas (3-1) from the permeate side of the first hydrogen membrane (HM-1) of the hydrogen-rich separation unit is mixed with the medium-pressure steam (3-2) to obtain the inlet gas (3-3) of the water-gas shift reactor. After passing through the water-gas shift reactor (WGS), the outlet low-hydrogen shift gas (3-4) of the water-gas shift reactor is obtained. After being cooled by heat recovery in the first heat exchanger (E-1), the shift gas (3-5) is sent to the low-hydrogen separation unit.

[0009] The fuel gas treatment unit includes a second heat exchanger E-2, a liquid separator SEP, and a decarbonization unit CO2-SEP. The outlet of the second heat exchanger E-2 is connected to the inlet of the liquid separator SEP. Free water (Water) leaves the system from the liquid phase outlet of the liquid separator SEP, and the gas phase outlet of the liquid separator SEP is connected to the inlet of the decarbonization unit CO2-SEP. The gas from the anode outlet of the first electrochemical hydrogen pump EHP-1 from the low-hydrogen separation unit is cooled by the second heat exchanger E-2, dehydrated by the liquid separator SEP, and decarbonized by the decarbonization unit CO2-SEP to obtain decarbonized fuel gas F1-4. The CO2 removed by the decarbonization unit CO2-SEP leaves the system.

[0010] A method for producing hydrogen from H2 / CO byproduct gas with a wide concentration range, integrating a high-temperature electrochemical hydrogen pump with water-gas shift conversion, is disclosed. The hydrogen production system using the H2 / CO byproduct gas has two operating modes: I) a two-stage membrane-single hydrogen pump, and II) a single-stage membrane-dual hydrogen pump. Mode I is used when the hydrogen content of the feedstock is higher than 50 vol%, and Mode II is used when the hydrogen content of the feedstock is lower than 50 vol%, as detailed below: (I) Two-stage membrane-single hydrogen pump mode By fully leveraging the advantages of single-hydrogen concentration through membrane separation, the hydrogen recovery rate of the membrane separation-pressure swing adsorption (PSA) integrated unit can be maximized. At this point, only the first electrochemical hydrogen pump, EHP-1, needs to be activated, reducing the separation load and investment cost of the electrochemical hydrogen pump. This achieves efficient hydrogen production while minimizing the unit hydrogen separation cost. In this mode, the H2 / CO byproduct gas 1-1 is pressurized by the first compressor K-1 to obtain pressurized byproduct gas 1-2, which enters the first hydrogen membrane HM-1; the high-CO and low-hydrogen permeate gas 3-1 from the first hydrogen membrane is mixed with medium-pressure steam 3-2 to obtain the inlet gas 3-3 of the water-gas shift reactor, which enters the water-gas shift reactor WGS; the permeate gas 1-3 from the first hydrogen membrane and the permeate gas 1-9 from the second hydrogen membrane are mixed by the first mixer MIX-1 to obtain membrane separation mixed permeate gas 1-4, which enters the second compressor K-2; After pressurization, pressurized hydrogen-rich permeate gas 1-5 is obtained, which enters the pressure swing adsorption tower (PSA) for purification. The high-purity hydrogen H1-1 at the top of the PSA tower is high-purity fuel cell hydrogen. The low-pressure PSA desorption gas 1-6 passes through the first three-way valve S-1 and the first control valve V-1 to obtain the first three-way first stage outlet gas 1-7, which enters the third compressor K-3 for pressurization. After pressurization, pressurized hydrogen-rich desorption gas 1-8 is obtained, which enters the second hydrogen membrane HM-2 for further concentration to obtain the second hydrogen membrane permeate gas 1-9. After being mixed with the first hydrogen membrane permeate gas 1-3, it is recycled into the pressure swing adsorption tower PSA for purification. The low-hydrogen permeate gas 2-2 from the second hydrogen membrane and the cooled shift gas 3-5 from the water-gas shift unit are mixed by the second mixer MIX-2 to obtain the anode inlet gas 2-3 of the first electrochemical hydrogen pump, which enters the first electrochemical hydrogen pump EHP-1 to separate low hydrogen; the cathode side obtains the high-purity hydrogen H1-2 of the first electrochemical hydrogen pump cathode, which is mixed with the high-purity hydrogen H1-1 from the top of the pressure swing adsorption tower and then sent out as fuel cell hydrogen product H1-4. The anode outlet gas F1-1 of the first electrochemical hydrogen pump EHP-1 is obtained. After being cooled by the second heat exchanger E-2, it becomes the liquid phase F1-2 at the inlet of the separator. It then enters the separator for SEP to remove free water. The gas F1-3 at the top of the separator further enters the decarbonization unit CO2-SEP to remove carbon dioxide CO2, resulting in decarbonized fuel gas F1-4. Finally, high-calorific-value fuel gas product F1-5 is obtained.

[0011] (II) Single-stage membrane-dual hydrogen pump mode Fully leverage the advantages of electrochemical hydrogen pumps in one-step purification and pressurization of low-hydrogen and low-pressure gases, reduce compressor investment and the operating power consumption of the second compressor K-2 in the hydrogen-rich separation unit, and reduce the unit comprehensive energy consumption and equipment investment of the hydrogen production system. In this mode, the H2 / CO byproduct gas 1-1 is pressurized by the first compressor K-1 to obtain pressurized byproduct gas 1-2, which enters the first hydrogen membrane HM-1; the first hydrogen membrane permeate gas 1-3 and the second hydrogen membrane permeate gas 1-9 are mixed by the first mixer MIX-1 to obtain membrane separation mixed permeate gas 1-4, which enters the second compressor K-2; after pressurization, pressurized hydrogen-rich permeate gas 1-5 is obtained, which enters the pressure swing adsorption (PSA) tower for purification, and the high-purity hydrogen H1-1 at the top of the PSA tower is high-purity fuel cell hydrogen; the first hydrogen membrane high CO Low-hydrogen permeate gas 3-1 is mixed with medium-pressure steam 3-2 to obtain inlet gas 3-3 of the water-gas shift reactor, which enters the water-gas shift reactor WGS to obtain low-hydrogen shift gas 3-4 at the outlet of the water-gas shift reactor; after heat recovery in the first heat exchanger E-1, cooled shift gas 3-5 is obtained, which enters the first electrochemical hydrogen pump EHP-1 to separate low-hydrogen; high-purity hydrogen H1-2 is obtained at the cathode side of the first electrochemical hydrogen pump cathode, which is mixed with high-purity hydrogen H1-1 at the top of the pressure swing adsorption tower and then sent out as fuel cell hydrogen product H1-4. The anode outlet gas F1-1 from the first electrochemical hydrogen pump is obtained. After being cooled by the second heat exchanger E-2, the liquid phase F1-2 is obtained as the inlet gas of the separator. It enters the separator for SEP to remove free water. The gas F1-3 at the top of the separator further enters the decarbonization unit CO2-SEP to remove carbon dioxide CO2, resulting in decarbonized fuel gas F1-4. Finally, high-calorific-value fuel gas product F1-5 is obtained. The desorbed gas 1-6 from the pressure swing adsorption (PSA) tower passes through the first three-way valve S-1 and the second control valve V-2 to obtain the second outlet gas 2-1 of the first three-way valve, which then enters the second electrochemical hydrogen pump EHP-2. Fuel gas is obtained at the anode outlet and mixed with the CO2-removed fuel gas F1-4 to form the fuel gas product. High-purity hydrogen H1-3 from the cathode of the second electrochemical hydrogen pump is obtained at the cathode and mixed with high-purity hydrogen H1-2 from the cathode of the first electrochemical hydrogen pump and high-purity hydrogen H1-1 from the top of the PSA tower, then exported as fuel cell hydrogen product H1-4. The beneficial effects of this invention are: by integrating gas membrane separation, pressure swing adsorption, and high-temperature electrochemical hydrogen pump separation technologies in different advantageous hydrogen separation ranges and coupling them with the water-gas shift reaction, the hydrogen yield and calorific value of the fuel gas in the H2 / CO by-product hydrogen production process are improved; for different raw material hydrogen contents, the separation order of membrane separation and electrochemical hydrogen pump can be flexibly switched through a "one-click adjustment" control unit, allowing for flexible and efficient recovery of PSA desorbed hydrogen even under fluctuating raw material hydrogen content. The system proposed in this invention fundamentally avoids the key problems of high yield and high purity recovery and the difficulty in efficient utilization of CO components that cannot be achieved simultaneously by single membrane separation and pressure swing adsorption. It utilizes the advantages of synergistic coupling and efficiency enhancement of multiple separation technologies with water-gas shift, and flexibly switches appropriate separation processes according to the rich hydrogen content of the gas, ensuring the optimal operation of the system under a wide range of hydrogen concentrations. While substantially improving the hydrogen yield, it significantly reduces the unit consumption and cost of hydrogen separation, which has significant economic benefits and environmental effects in today's rapidly developing "hydrogen economy". Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the system of the present invention.

[0013] K-1, First compressor; K-2, Second compressor; K-3, Third compressor; HM-1, First hydrogen membrane; HM-2, Second hydrogen membrane; PSA, Pressure Swing Adsorption; EHP-1, First electrochemical hydrogen pump; EHP-2, Second electrochemical hydrogen pump; WGS, Water-Gas Shift Reactor; E-1, First heat exchanger; E-2, Second heat exchanger; SEP, Separator; CO2-SEP, Decarbonization unit.

[0014] 1-1. Byproduct gas containing H2 / CO; 1-2. Pressurized byproduct gas; 1-3. First hydrogen membrane permeate gas; 1-4. Membrane separation mixed permeate gas; 1-5. Pressurized hydrogen-rich permeate gas; 1-6. Pressure swing adsorption desorption gas; 1-7. First stage outlet gas of the first three-way valve; 1-8. Pressurized hydrogen-rich desorption gas; 1-9. Second hydrogen membrane permeate gas; 2-1. Outlet gas from the second stage of the first three-way valve; 2-2. Residual gas from the low-hydrogen permeation of the second hydrogen membrane; 2-3. Inlet gas from the anode of the first electrochemical hydrogen pump; 3-1. High-CO, low-hydrogen permeate gas from the first hydrogen membrane; 3-2. Medium-pressure steam; 3-3. Inlet gas of the water-gas shift reactor; 3-4. Low-hydrogen shift gas at the outlet of the water-gas shift reactor; 3-5. Shift gas after cooling; H1-1, High-purity hydrogen from the top of the pressure swing adsorption tower; H1-2, High-purity hydrogen from the cathode of the first electrochemical hydrogen pump; H1-3, High-purity hydrogen from the cathode of the second electrochemical hydrogen pump; H1-4, Hydrogen products delivered to fuel cells. Water, free water; CO2, removed carbon dioxide; F1-1, Anode outlet gas of the first electrochemical hydrogen pump; F1-2, Inlet gas of the separator (containing liquid phase); F1-3, Top gas of the separator; F1-4, Fuel gas after CO2 removal; V-1, First control valve; V-2, Second control valve; V-3, Third control valve; V-4, Fourth control valve; S-1, First three-way valve; MIX-1, First mixer; MIX-2, Second mixer. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0016] See Figure 1 The system of the present invention includes a first compressor K-1, a second compressor K-2, a third compressor K-3, a first hydrogen membrane HM-1, a second hydrogen membrane HM-2, a pressure swing adsorption (PSA), a first electrochemical hydrogen pump EHP-1, a second electrochemical hydrogen pump EHP-2, a water-gas shift reactor (WGS), a first heat exchanger E-1, a second heat exchanger E-2, a liquid separator (SEP), and a decarbonization unit CO2-SEP.

[0017] This system improves the hydrogen yield and fuel gas calorific value in the hydrogen production process containing H2 / CO byproduct gas by integrating gas membrane separation, pressure swing adsorption, and high-temperature electrochemical hydrogen pump separation technologies in different advantageous hydrogen separation ranges and coupling them with water-gas shift reaction. For different byproduct gas hydrogen contents, the system allows for flexible switching between membrane separation and electrochemical hydrogen pump through "one-click adjustment" of the control unit, and efficiently recovers hydrogen desorbed by pressure swing adsorption.

[0018] Example 1 The high-hydrogen-content coke oven gas (H2: 65 vol%, CO: 4 vol%, CH4: 17.2 vol%, N2: 8.75 vol%, CO2: 2.14 vol%, C2) after pretreatment in the purification unit of a coking plant is analyzed. + (2.91 vol%), pressure 0.5 MPa, temperature 25℃, flow rate 8000 Nm³ 3 ·h -1Using the hydrogen production process described in this system, with a hydrogen concentration higher than 50 vol%, mode (I) is activated. At this time, the hydrogen concentration and flow rate in the desorbed gas of the pressure swing adsorption (PSA) are relatively high. Therefore, mode (I) first uses the second hydrogen membrane HM-2 to concentrate the hydrogen gas, and then uses the electrochemical hydrogen pump to recover the residual hydrogen gas in the permeate gas of the second hydrogen membrane HM-2. This can reduce the separation load and energy consumption of the electrochemical hydrogen pump, thereby reducing investment and operating costs. Through the "one-key adjustment" operation mode of the control unit, the first control valve V-1, the third control valve V-3, and the fourth control valve V-4 are opened; the second control valve V-2 is closed; and the first electrochemical hydrogen pump EHP-1 is activated.

[0019] Coke oven gas 1-1 from the outside is pressurized to 3.0 MPa by the first compressor K-1 to obtain pressurized by-product gas 1-2 (pressurized coke oven gas), which enters the first hydrogen membrane HM-1; permeate gas 1-3 (H2: 94.4 vol%, CO: 0.38 vol%) is mixed with permeate gas 1-9 from the second hydrogen membrane HM-2, and the resulting stream 1-4 (H2: 94 vol%, CO: 0.33 vol%), at a pressure of 0.2 MPa, enters the second compressor K-2. The pressurized hydrogen-rich permeate gas 1-5, above 3.0 MPa, enters the pressure swing adsorption (PSA) system, where the PSA hydrogen recovery rate is 77%; residual permeate gas 3-1 (H2: 16.7 vol%, CO: 10 vol%) from the first hydrogen membrane HM-1 is mixed with medium-pressure steam 3-2 (pressure 3 MPa, temperature 250℃) and then enters the water-gas shift reactor (WGS). Temperature: 150℃, H2O / CO ratio: 1.0) converts to CO, with a CO conversion rate of 86.1%; high-purity hydrogen H1-1 (H2: 99.99 vol%) is obtained at the top of the PSA tower, along with PSA desorption gas 1-6 (H2: 78 vol%, CO: 1.2 vol%), at a pressure of 0.1 MPa. This gas enters the third compressor K-3 via three-way valve S-1 and the first control valve V-1, where it is pressurized to 3.0 MPa. The pressurized desorption gas 1-8 enters the second hydrogen membrane HM-2, and the permeate gas 1-9 (H2: 92 vol%, CO: 0.04 vol%) mixes with the permeate gas 1-3 from the first hydrogen membrane HM-1 and is then circulated and separated at a pressure of 0.2 MPa. The residual permeate gas from the second hydrogen membrane HM-2 (H2: 57.2 vol%, CO: 2.9 vol%) mixes with the cooled shifted gas 3-5 from the water-gas shift unit (H2: The hydrogen molecules (H2: 22.9 vol%, CO: 1.3 vol%, H2O: 1.2 vol%) were mixed in the second mixer MIX-2 to obtain stream 2-3 (H2: 28.5 vol%, CO: 1.5 vol%), which then entered the first electrochemical hydrogen pump EHP-1, operating at a current density of 0.96 A·cm⁻¹. -2The operating temperature is 170 ℃, the hydrogen recovery rate is 99.32%, and the cathode and anode pressures are both 3.0 MPa. High-purity hydrogen H1-2 (H2: 99.99 vol%) is obtained from the cathode, which is mixed with high-purity hydrogen H1-1 from the PSA tower top and then exported as fuel cell hydrogen product H1-4. The system hydrogen yield is […]. Taking into account raw materials and the newly added H2 from WGS, the percentage is 98.8%.

[0020] The anode outlet gas of the first electrochemical hydrogen pump EHP-1 contains H2: 0.27 vol%, CO: 2.14 vol%, CH4: 48.3 vol%, N2: 24.6 vol%, CO2: 15.1 vol%, H2O: 1.47 vol%, and C2: 0.27 vol%. + The first gas (H2: 0.21 vol%) at 170℃ enters the second heat exchanger E-2, where it is cooled to 30℃ and then enters the separator SEP to remove condensate. The top gas F1-3 enters the decarbonization unit CO2-SEP, where CO2 is removed to obtain fuel gas (H2: 0.26 vol%, CO: 2.6 vol%, CH4: 57.8 vol%, N2: 29.4 vol%, H2O: 0.3 vol%, C2). + (4.43 vol%) delivered externally, calorific value 25.6 MJ·Nm³ -3 Compared to the calorific value of coke oven gas at this hydrogen content (15.2 MJ·Nm³), -3 The efficiency has increased by 1.7 times, with a unit comprehensive hydrogen production energy consumption of 4.15 kWh·kg. -1 .

[0021] Example 2 For coke oven gas with medium hydrogen content (H2: 45 vol%, CO: 8 vol%, CH4: 32.35 vol%, N2: 8.75 vol%, CO2: 3 vol%, C2) after pretreatment in a purification unit of a coking plant... + (2.85 vol%), pressure 0.5 MPa, temperature 25 ℃, flow rate 8000 Nm³ 3 ·h -1 Using the hydrogen production process described in this system, the hydrogen concentration is less than 50 vol%. Therefore, mode (II) is activated to directly use the second electrochemical hydrogen pump EHP-2 to purify the hydrogen in the low-pressure desorbed gas of PSA, reducing compressor investment and operating costs. Through the "one-key adjustment" operation mode of the control unit, the first control valve V-1, the third control valve V-3, and the fourth control valve V-4 are closed; the second control valve V-2 is opened; and the first electrochemical hydrogen pump EHP-1 and the second electrochemical hydrogen pump EHP-2 are activated.

[0022] Coke oven gas 1-1 from the outside is pressurized to 3.0 MPa by the first compressor K-1 to obtain pressurized by-product gas 1-2 (pressurized coke oven gas), which enters the first hydrogen membrane HM-1; permeate gas 1-3 (H2: 89.9 vol%, CO: 0.88 vol%), at a pressure of 0.2 MPa, enters the second compressor K-2, and hydrogen-rich permeate gas 1-5 at 3.0 MPa enters the pressure swing adsorption (PSA) system, with a PSA hydrogen recovery rate of 76%; residual permeate gas 3-1 (H2: 9 vol%, CO: 13.7 vol%) from the first hydrogen membrane HM-1 is mixed with medium-pressure steam 3-2 and then enters the water-gas shift reactor (WGS). (Temperature: 150℃, H2O / CO ratio: 1.0) CO is converted, with a CO conversion rate of 86.9%. High-purity hydrogen H1-1 (H2: 99.99 vol%) is obtained at the top of the PSA tower, along with PSA desorption gas 1-6 (H2: 68.5 vol%, CO: 2.7 vol%) at a pressure of 0.1 MPa. This gas then enters the second electrochemical hydrogen pump EHP-2 via three-way valve S-1 and second control valve V-2 to separate hydrogen. The operating temperature is 170℃, anode pressure is 0.1 MPa, cathode pressure is 3 MPa, and operating current density is 0.47 A·cm³. -2 The hydrogen recovery rate is 99.94%. High-purity hydrogen H1-3 (H2: 99.99 vol%) is obtained at the cathode, and fuel gas (H2: 0.13 vol%, CO: 8.72 vol%, CH4: 33.7 vol%, N2: 9.5 vol%, CO2: 43.2 vol%, C2) is obtained at the anode outlet. + The cooled shifted gas 3-5 (H2: 18.33 vol%, CO: 1.6 vol%, H2O: 1.6 vol%) from the water-gas shift unit enters the first electrochemical hydrogen pump EHP-1, with an operating current density of 0.97 A·cm⁻¹. -2 The operating temperature is 170 ℃, and the cathode and anode pressures are both 3.0 MPa. The hydrogen recovery rate is 96.4%. High-purity hydrogen H1-2 (H2: 99.99 vol%) is obtained from the cathode. This high-purity hydrogen is mixed with high-purity hydrogen H1-1 from the top of the PSA tower, high-purity hydrogen H1-2 from the cathode of the first electrochemical hydrogen pump, and high-purity hydrogen H1-3 from the cathode of the second electrochemical hydrogen pump, and then exported as fuel cell hydrogen product H1-4. The overall hydrogen yield of the system is […]. Taking into account raw materials and the newly added H2 from WGS, the figure is 98.2%.

[0023] The anode outlet gas of the first electrochemical hydrogen pump EHP-1 contains H2: 0.81 vol%, CO: 1.9 vol%, CH4: 59.4 vol%, N2: 16 vol%, CO2: 14.8 vol%, H2O: 1.92 vol%, and C2... +The first gas (H2: 5.17 vol%), at a temperature of 170℃, enters the second heat exchanger E-2 to be cooled to 30℃ and then enters the separator SEP to remove condensate (Water). The top gas F1-3 enters the decarbonization unit CO2-SEP, where CO2 is removed to obtain fuel gas F1-4 (H2: 0.96 vol%, CO: 2.3 vol%, CH4: 71.2 vol%, N2: 19.2 vol%, H2O: 0.3 vol%, C2). + The fuel gas stream, containing 1.61 vol%, is mixed with the anode outlet gas of the second electrochemical hydrogen pump EHP-2 to obtain fuel gas products (H2: 0.89 vol%, CO: 2.9 vol%, CH4: 67.6 vol%, N2: 18.3 vol%, CO2: 4.1 vol%, H2O: 0.17 vol%, C2). + (0.87 vol%), calorific value 21.9 MJ·Nm -3 Compared to the calorific value of coke oven gas at this hydrogen content (19 MJ·Nm³), -3 The efficiency has increased by 1.2 times, with a unit comprehensive hydrogen production energy consumption of 5.11 kWh·kg. -1 .

[0024] Example 3 For the low-hydrogen catalytic cracking dry gas of a certain petrochemical plant (H2: 22.7 vol%, CO: 2 vol%, CH4: 21.19 vol%, N2: 24.07 vol%, CO2: 3.5 vol%, C2...), + (26.54 vol%), pressure 0.85 MPa, temperature 40 ℃, flow rate 8000 Nm³ 3 ·h -1 Using the hydrogen production process described in this system, the hydrogen concentration is only 22.7 vol%, far lower than 50 vol%, which is a low-hydrogen H2 / CO by-product gas. Therefore, in mode (II), the second electrochemical hydrogen pump EHP-2 is used to purify the low-pressure desorbed PSA gas, reducing compressor investment and operating costs. Through the "one-click adjustment" operation mode of the control unit, the first control valve V-1, the third control valve V-3, and the fourth control valve V-4 are closed; the second control valve V-2 is opened; and the first electrochemical hydrogen pump EHP-1 and the second electrochemical hydrogen pump EHP-2 are activated.

[0025] Low-hydrogen catalytic cracking dry gas 1-1 from the outside is pressurized to 3.0 MPa by the first compressor K-1 to obtain pressurized by-product gas 1-2, which enters the first hydrogen membrane HM-1; permeate gas 1-3 (H2: 78.6 vol%, CO: 0.35 vol%), at a pressure of 0.2 MPa, enters the second compressor K-2, and hydrogen-rich permeate gas 1-5 at 3.0 MPa enters the pressure swing adsorption (PSA) system, with a PSA hydrogen recovery rate of 69.1%; residual permeate gas 3-1 (H2: 9 vol%, CO: 13.7 vol%) from the first hydrogen membrane HM-1 is mixed with medium-pressure steam 3-2 and then enters the water-gas shift reactor (WGS). The system (temperature: 150℃, H2O / CO ratio: 1.0) converts CO to hydrogen with a conversion rate of 88.3%. High-purity hydrogen H1-1 (H2: 99.99 vol%) is obtained at the top of the PSA tower, along with PSA desorption gas 1-6 (H2: 53.2 vol%, CO: 0.77 vol%) at a pressure of 0.1 MPa. This hydrogen is then separated by the second electrochemical hydrogen pump EHP-2 via a three-way valve S-1 and a second control valve V-2. The operating temperature is 170℃, the anode pressure is 0.1 MPa, the cathode pressure is 3 MPa, and the operating current density is 0.36 A·cm³. -2 The hydrogen recovery rate is 99.95%. High-purity hydrogen H1-3 (H2: 99.99 vol%) is obtained at the cathode, and fuel gas (H2: 0.06 vol%, CO: 1.65 vol%, CH4: 16.74 vol%, N2: 25.81 vol%, CO2: 38.92 vol%, C2) is obtained at the anode outlet. + The cooled shifted gas 3-5 (H2: 9.26 vol%, CO: 0.28 vol%, H2O: 0.28 vol%) from the water-gas shift unit enters the first electrochemical hydrogen pump EHP-1, with an operating current density of 0.71 A·cm⁻¹. -2 The operating temperature is 170 ℃, and the cathode and anode pressures are both 3.0 MPa. The hydrogen recovery rate is 99.12%. High-purity hydrogen H1-2 (H2: 99.99 vol%) is obtained from the cathode. This high-purity hydrogen is mixed with high-purity hydrogen H1-1 from the top of the PSA tower, high-purity hydrogen H1-2 from the cathode of the first electrochemical hydrogen pump, and high-purity hydrogen H1-3 from the cathode of the second electrochemical hydrogen pump, and then sent out as fuel cell hydrogen product H1-4. The overall hydrogen yield of the system is […]. Taking into account raw materials and the newly added H2 from WGS, the percentage is 98.5%.

[0026] The anode outlet gas of the first electrochemical hydrogen pump EHP-1 contains H2: 0.09 vol%, CO: 0.31 vol%, CH4: 27.98 vol%, N2: 31.36 vol%, CO2: 4.66 vol%, H2O: 0.31 vol%, and C2: 0.31 vol%.+ The first gas (H2: 0.09 vol%, CO: 0.33 vol%, CH4: 29.39 vol%, N2: 32.93 vol%, H2O: 0.18 vol%, C2) at 170℃ enters the second heat exchanger E-2 to be cooled to 30℃ and then enters the separator SEP to remove condensate (Water). The top gas F1-3 enters the decarbonization unit CO2-SEP, where CO2 is removed to obtain fuel gas F1-4 (H2: 0.09 vol%, CO: 0.33 vol%, CH4: 29.39 vol%, N2: 32.93 vol%, H2O: 0.18 vol%, C2). + The fuel gas stream (H2: 0.09 vol%, CO: 0.41 vol%, CH4: 28.6 vol%, N2: 32.5 vol%, CO2: 2.42 vol%, H2O: 0.17 vol%, C2) was mixed with the anode outlet gas of the second electrochemical hydrogen pump EHP-2 to obtain the fuel gas product (H2: 0.09 vol%, CO: 0.41 vol%, CH4: 28.6 vol%, N2: 32.5 vol%, CO2: 2.42 vol%, H2O: 0.17 vol%, C2). + (35.81 vol%), calorific value 32.9 MJ·Nm -3 Compared to the calorific value of catalytic cracking dry gas (27 MJ·Nm³), -3 The efficiency has increased by 1.22 times, and the unit comprehensive hydrogen production energy consumption is 7.8 kWh·kg. -1 .

[0027] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature electrochemical hydrogen pump integrated with water-gas shift converter, comprising a wide-concentration hydrogen production system containing H2 / CO byproduct gas, characterized in that: The hydrogen production system includes a hydrogen-rich separation unit, a low-hydrogen separation unit, a fuel gas processing unit, and a water-gas conversion unit. In the hydrogen-rich separation unit, the H2 / CO by-product gas feedstock is compressed, membrane separated and pressure swing adsorption processes to concentrate hydrogen from the hydrogen-containing by-product gas and produce high-purity hydrogen product gas; at the same time, hydrogen-containing desorption gas and low-hydrogen permeate gas are generated for subsequent unit processing. The low-hydrogen separation unit uses high-temperature electrochemical hydrogen pump technology to purify low-hydrogen gas, further recover hydrogen gas and produce high-purity hydrogen; the anode outlet gas of the high-temperature electrochemical hydrogen pump is used as fuel gas product. The water-gas conversion unit utilizes a water-gas conversion reactor to react low-hydrogen permeate gas containing high concentrations of carbon monoxide with water vapor to convert it into hydrogen gas; at the same time, the heat of the reaction products is recovered through a heat exchanger to achieve gas composition adjustment and thermal energy utilization. The fuel gas processing unit cools, separates, and removes carbon dioxide from the gas from upstream to obtain a high-calorific-value fuel gas product that meets the requirements; and separates free water and carbon dioxide and discharges them from the system.

2. The high-temperature electrochemical hydrogen pump and water-gas shift integrated wide-concentration H2 / CO by-product gas hydrogen production system according to claim 1, characterized in that: The hydrogen-rich separation unit includes a first compressor (K-1), a second compressor (K-2), a third compressor (K-3), a first hydrogen membrane (HM-1), a second hydrogen membrane (HM-2), and a pressure swing adsorption (PSA) tower. The inlet of the first compressor (K-1) is connected to a byproduct gas containing H2 / CO (1-1), and its outlet is connected to the inlet side of the first hydrogen membrane (HM-1), supplying pressurized byproduct gas (1-2) to the first hydrogen membrane (HM-1). The concentrated hydrogen outlet on the permeate side of the first hydrogen membrane (HM-1) is connected to the inlet of the first mixer (MIX-1), supplying first hydrogen membrane permeate gas (1-3) to the first mixer (MIX-1). The inlet of the first mixer (MIX-1) is also connected to the concentrated hydrogen outlet on the permeate side of the second hydrogen membrane (HM-2). The second hydrogen membrane (HM-2) supplies second hydrogen membrane permeate gas (1-9) to the first mixer (MIX-1). The second hydrogen membrane (HM-2) and the first mixer... A third control valve (V-3) is installed between the first mixer (MIX-1); the outlet of the first mixer (MIX-1) is connected to the inlet of the second compressor (K-2), providing the second compressor (K-2) with membrane separation mixed permeate gas (1-4); the outlet of the second compressor (K-2) is connected to the inlet of the pressure swing adsorption (PSA) tower, providing the PSA tower with pressurized hydrogen-rich permeate gas (1-5); the high-purity hydrogen (H1-1) at the top of the PSA tower is separated from the high-purity hydrogen (H1-2) output from the first electrochemical hydrogen pump (EHP-1) in the low-hydrogen separation unit, and the high-purity hydrogen (H1-2) output from the cathode of the first electrochemical hydrogen pump (EHP-1) in the low-hydrogen separation unit is separated from the high-purity hydrogen (H1-2) output from the cathode of the second electrochemical hydrogen pump (EHP-2). The high-purity hydrogen (H1-3) at the cathode of the second electrochemical hydrogen pump is mixed and then sent out of the system as the fuel cell hydrogen product (H1-4). The desorbed gas outlet of the pressure swing adsorption (PSA) tower is connected to the inlet of the third compressor (K-3) via the first three-way valve (S-1) and the first control valve (V-1) to supply the PSA tower desorbed gas (1-6) to the third compressor (K-3). The PSA tower desorbed gas (1-6) is divided into two paths via the first three-way valve (S-1): one path is connected to the third compressor (K-3) via the first control valve (V-1), and the other path is connected to the anode of the second electrochemical hydrogen pump (EHP-2) via the second control valve (V-2). The outlet of the third compressor (K-3) is connected to the inlet of the second hydrogen membrane (HM-2) to supply pressurized hydrogen-rich desorption gas (1-8) to the second hydrogen membrane (HM-2); the outlet of the permeate side of the second hydrogen membrane (HM-2) is connected to the second mixer (MIX-2) via the fourth control valve (V-4) to supply the second mixer (MIX-2) with the second hydrogen membrane low-hydrogen permeate gas (2-2), so that the second hydrogen membrane low-hydrogen permeate gas (2-2) enters the low-hydrogen separation unit; the outlet of the permeate side of the first hydrogen membrane (HM-1) is connected to the inlet of the water-gas shift reactor (WGS) to supply the water-gas shift reactor (WGS) with the first hydrogen membrane high-CO low-hydrogen permeate gas (3-1), so that the first hydrogen membrane high-CO low-hydrogen permeate gas (3-1) enters the water-gas shift unit; The low-hydrogen separation unit includes a first electrochemical hydrogen pump (EHP-1) and a second electrochemical hydrogen pump (EHP-2). The low-hydrogen permeate gas (2-2) from the second hydrogen membrane of the hydrogen-rich separation unit and the cooled shift gas (3-5) from the water-gas shift unit are mixed via a second mixer (MIX-2) to obtain the anode inlet gas (2-3) of the first electrochemical hydrogen pump. The outlet of the second mixer (MIX-2) is connected to the anode inlet side of the first electrochemical hydrogen pump (EHP-1), supplying the anode inlet gas (2-3) of the first electrochemical hydrogen pump (EHP-1). The anode outlet of the electrochemical hydrogen pump is connected to the inlet of the second heat exchanger (E-2) of the fuel gas treatment unit, supplying the anode outlet gas (F1-1) of the first electrochemical hydrogen pump to the second heat exchanger (E-2); the pressure swing adsorption desorption gas (1-6) from the hydrogen-rich separation unit is connected to the anode inlet of the second electrochemical hydrogen pump (EHP-2) via the first three-way valve (S-1) and the second control valve (V-2); the anode outlet gas of the second electrochemical hydrogen pump (EHP-2) is mixed with the de-CO2 fuel gas (F1-4) from the fuel gas treatment unit and then leaves the system as fuel gas product (F1-5). The water-gas shift unit includes a water-gas shift reactor (WGS) and a first heat exchanger (E-1). The inlet of the water-gas shift reactor (WGS) is also connected to medium-pressure steam (3-2), and the outlet is connected to the inlet of the second mixer (MIX-2) via the first heat exchanger (E-1). The high-CO and low-hydrogen permeate gas (3-1) from the permeate side of the first hydrogen membrane (HM-1) of the hydrogen-rich separation unit is mixed with the medium-pressure steam (3-2) to obtain the inlet gas (3-3) of the water-gas shift reactor. After passing through the water-gas shift reactor (WGS), the low-hydrogen shift gas (3-4) of the water-gas shift reactor is obtained. After being cooled by heat recovery in the first heat exchanger (E-1), the shift gas (3-5) is sent to the low-hydrogen separation unit. The fuel gas processing unit includes a second heat exchanger (E-2), a liquid separator (SEP), and a decarbonization unit (CO2-SEP). The outlet of the second heat exchanger (E-2) is connected to the inlet of the liquid separator (SEP). Free water leaves the system from the liquid phase outlet of the liquid separator (SEP), and the gas phase outlet of the liquid separator (SEP) is connected to the inlet of the decarbonization unit (CO2-SEP). The anode outlet gas from the first electrochemical hydrogen pump (EHP-1) of the low-hydrogen separation unit is cooled by the second heat exchanger (E-2), dehydrated by the liquid separator (SEP), and decarbonized by the decarbonization unit (CO2-SEP) to obtain decarbonized fuel gas (F1-4). The CO2 removed by the decarbonization unit (CO2-SEP) leaves the system.

3. A method for producing hydrogen from H2 / CO byproduct gas of a wide concentration using a high-temperature electrochemical hydrogen pump and a water-gas shift integrated system as described in claim 1, characterized in that: The hydrogen production system containing H2 / CO byproduct gas has two operating modes: (I) two-stage membrane-single hydrogen pump and (II) single-stage membrane-dual hydrogen pump. Mode (I) is used when the hydrogen content of the feedstock is higher than 50 vol%, and mode (II) is used when the hydrogen content of the feedstock is lower than 50 vol%, as detailed below: (I) Two-stage membrane-single hydrogen pump mode In this mode, the H2 / CO byproduct gas (1-1) is pressurized by the first compressor (K-1) to obtain pressurized byproduct gas (1-2), which enters the first hydrogen membrane (HM-1); the high-CO, low-hydrogen permeate gas (3-1) from the first hydrogen membrane is mixed with medium-pressure steam (3-2) to obtain the inlet gas (3-3) of the water-gas shift reactor, which enters the water-gas shift reactor (WGS); the permeate gas (1-3) from the first hydrogen membrane and the permeate gas (1-9) from the second hydrogen membrane are mixed by the first mixer (MIX-1) to obtain the membrane separation mixed permeate gas (1-4), which enters the second compressor (K-2). After pressurization, pressurized hydrogen-rich permeate gas (1-5) is obtained, which enters the pressure swing adsorption (PSA) tower for purification. The high-purity hydrogen (H1-1) at the top of the PSA tower is high-purity fuel cell hydrogen. The low-pressure PSA desorption gas (1-6) passes through the first three-way valve (S-1) and the first control valve (V-1) to obtain the first three-way first stage outlet gas (1-7), which enters the third compressor (K-3) for pressurization. After pressurization, pressurized hydrogen-rich desorption gas (1-8) is obtained, which enters the second hydrogen membrane (HM-2) for further concentration to obtain the second hydrogen membrane permeate gas (1-9). After mixing with the first hydrogen membrane permeate gas (1-3), it is recycled into the pressure swing adsorption tower (PSA) for purification. The low-hydrogen permeate gas (2-2) from the second hydrogen membrane and the cooled shift gas (3-5) from the water-gas shift unit are mixed in the second mixer (MIX-2) to obtain the anode inlet gas (2-3) of the first electrochemical hydrogen pump, which enters the first electrochemical hydrogen pump (EHP-1) to separate low-hydrogen; the cathode side obtains the high-purity hydrogen (H1-2) of the first electrochemical hydrogen pump cathode, which is mixed with the high-purity hydrogen (H1-1) from the top of the pressure swing adsorption tower and then sent out as fuel cell hydrogen product (H1-4); The anode outlet gas (F1-1) of the first electrochemical hydrogen pump (EHP-1) is obtained from the anode side outlet. After being cooled by the second heat exchanger (E-2), it becomes the inlet gas (containing liquid phase) of the separator (SEP) (F1-2), which enters the separator (SEP) to remove free water. The gas at the top of the separator (F1-3) further enters the decarbonization unit (CO2-SEP) to remove carbon dioxide (CO2), resulting in decarbonized fuel gas (F1-4), and finally, high-calorific-value fuel gas product (F1-5). (II) Single-stage membrane-dual hydrogen pump mode In this mode, the H2 / CO byproduct gas (1-1) is pressurized by the first compressor (K-1) to obtain pressurized byproduct gas (1-2), which enters the first hydrogen membrane (HM-1); the permeate gas from the first hydrogen membrane (1-3) and the permeate gas from the second hydrogen membrane (1-9) are mixed by the first mixer (MIX-1) to obtain membrane-separated mixed permeate gas (1-4), which enters the second compressor (K-2); after pressurization, pressurized hydrogen-rich permeate gas (1-5) is obtained, which enters the pressure swing adsorption (PSA) tower for purification, and the high-purity hydrogen (H1-1) at the top of the PSA tower is high-purity fuel cell hydrogen; the first hydrogen membrane high CO Low-hydrogen permeate gas (3-1) is mixed with medium-pressure steam (3-2) to obtain inlet gas (3-3) of the water-gas shift reactor (WGS), which enters the WGS to obtain low-hydrogen shift gas (3-4) at the outlet of the WGS. After heat recovery in the first heat exchanger (E-1), cooled shift gas (3-5) is obtained, which enters the first electrochemical hydrogen pump (EHP-1) to separate low-hydrogen. High-purity hydrogen (H1-2) from the cathode of the first electrochemical hydrogen pump is obtained on the cathode side, which is mixed with high-purity hydrogen (H1-1) from the top of the pressure swing adsorption tower and then sent out as fuel cell hydrogen product (H1-4). The anode outlet of the first electrochemical hydrogen pump (F1-1) is cooled by the second heat exchanger (E-2) to obtain the inlet gas (containing liquid phase) of the separator (F1-2), which enters the separator (SEP) to remove free water. The gas at the top of the separator (F1-3) further enters the decarbonization unit (CO2-SEP) to remove carbon dioxide (CO2) and obtain the decarbonized fuel gas (F1-4), finally obtaining the high-calorific-value fuel gas product (F1-5). The desorbed gas (1-6) from the pressure swing adsorption tower passes through the first three-way valve (S-1) and the second control valve (V-2) to obtain the second outlet gas (2-1) of the first three-way valve, which then enters the second electrochemical hydrogen pump (EHP-2). Fuel gas is obtained at the anode outlet and is mixed with the de-CO2 fuel gas (F1-4) to form the fuel gas product (F1-5). High-purity hydrogen (H1-3) from the cathode of the second electrochemical hydrogen pump is obtained at the cathode and is mixed with high-purity hydrogen (H1-2) from the cathode of the first electrochemical hydrogen pump and high-purity hydrogen (H1-1) from the top of the pressure swing adsorption tower, and then sent out as the fuel cell hydrogen product (H1-4).

Images