A hydrogen production system and method for co-production of nitrogen

Abstract

The application discloses a hydrogen production system and method for co-production of nitrogen, which comprises a third oxygen-permeable membrane reactor, a fourth oxygen-permeable membrane reactor, a second oxygen-permeable membrane reactor, a first oxygen-permeable membrane reactor and a first condenser; the oxygen-poor air outlet of the third oxygen-permeable membrane reactor is communicated with the inlet of the fourth oxygen-permeable membrane reactor; the high-temperature gas three-outlet of the third oxygen-permeable membrane reactor is communicated with the inlet of the second oxygen-permeable membrane reactor; the high-temperature gas four-outlet of the fourth oxygen-permeable membrane reactor is communicated with the inlet of the second oxygen-permeable membrane reactor; the high-temperature gas two-outlet of the second oxygen-permeable membrane reactor is communicated with the inlet of the first oxygen-permeable membrane reactor; the hydrogen-rich gas outlet of the first oxygen-permeable membrane reactor is communicated with the inlet of the first condenser; and the high-temperature gas one-outlet of the first oxygen-permeable membrane reactor is communicated with the inlets of the third and fourth oxygen-permeable membrane reactors; the system can produce hydrogen conveniently, efficiently and economically and obtain high-purity nitrogen.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production, and more specifically to a hydrogen production system and method for co-producing nitrogen. Background Technology

[0002] Global energy primarily comprises traditional fossil fuels such as coal, oil, and natural gas, as well as emerging clean energy sources like wind, hydro, solar, ocean, and hydrogen. Traditional fossil fuels are non-renewable, and their combustion produces toxic gases and greenhouse gases that severely pollute the environment. With industrial development, energy demand is increasing daily. To address this growing demand and the need for low-carbon energy, and to accelerate the global transition from a fossil fuel economy to a low-carbon economy, the development of clean and inexpensive new energy sources is urgently needed. Hydrogen is a highly efficient and ideal clean energy source. Due to its numerous advantages, including pollution-free combustion, high energy density, high chemical reactivity, and abundant renewable resources, it is considered one of the more ideal energy sources to replace traditional fossil fuels.

[0003] Currently, hydrogen production can be categorized into four main processes and technologies: water electrolysis, fossil fuel-based hydrogen production, industrial by-product hydrogen production, and biomass-based hydrogen production. Water electrolysis is costly and limited to small-scale applications, hindering its widespread adoption. Fossil fuel-based hydrogen production uses non-renewable energy sources, consumes significant energy during the process, and impacts the environment, with large emissions of carbon dioxide contributing to the greenhouse effect. Industrial by-product hydrogen production produces hydrogen with low purity, requiring complex and energy-intensive purification systems that also generate greenhouse gases. Biomass-based hydrogen production also produces hydrogen with low purity, the technology is not yet fully mature, and investment costs are high.

[0004] An oxygen-permeable membrane is a novel type of oxygen separation membrane. Its principle is based on the oxygen partial pressure difference across the membrane at a certain temperature. Water vapor is decomposed into oxygen and hydrogen through the membrane's separation action. Oxygen diffuses from the high partial pressure side to the low partial pressure side, and the remaining hydrogen-rich water vapor is condensed and separated to produce high-purity hydrogen. Compared to conventional hydrogen production technologies, it offers advantages such as system simplicity, low energy consumption, rapid start-up, low cost, and convenient operation. Furthermore, the simultaneous production of high-purity nitrogen significantly improves the economics and system efficiency of hydrogen production technology.

[0005] Chinese patent document CN201410440172.0 discloses an apparatus for producing hydrogen by alternating decomposition of water using oxygen-permeable membranes and hydrogen-permeable membranes. The apparatus includes: a flat box-shaped body internally divided into several spaced-apart oxygen-permeable chambers and hydrogen-permeable chambers; and inner pipes extending within each oxygen-permeable and hydrogen-permeable chamber. The inner pipes of adjacent chambers are connected end-to-end by outer pipes, forming a connected serpentine vapor channel. The inner pipes in the oxygen-permeable chambers are made of oxygen-permeable membranes, and the inner pipes in the hydrogen-permeable chambers are made of hydrogen-permeable membranes. A chemical potential difference exists between the inner and outer sides of the hydrogen-permeable membrane in the hydrogen-permeable chamber and between the inner and outer sides of the oxygen-permeable membrane in the oxygen-permeable chamber. Under the influence of this chemical potential difference, oxygen permeates through the oxygen-permeable membrane, and hydrogen permeates through the hydrogen-permeable membrane, entering the area between the inner pipe and the corresponding chamber's inner wall, respectively. However, this system cannot produce nitrogen simultaneously with hydrogen production. Summary of the Invention

[0006] In order to overcome the shortcomings of existing technologies, the present invention aims to provide a hydrogen production system and method for co-producing nitrogen, which solves the problems of pollutants, system complexity and high cost of traditional hydrogen production technologies, and can obtain high-purity nitrogen while producing hydrogen in a convenient, efficient and economical manner.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A hydrogen production system that co-produces nitrogen includes a third oxygen-permeable membrane reactor, a fourth oxygen-permeable membrane reactor, a second oxygen-permeable membrane reactor, a first oxygen-permeable membrane reactor, and a first condenser;

[0009] The oxygen-deficient air outlet of the third oxygen-permeable membrane reactor is connected to the inlet of the fourth oxygen-permeable membrane reactor. The high-temperature gas outlet 3 of the third oxygen-permeable membrane reactor is connected to the inlet of the second oxygen-permeable membrane reactor. The high-temperature gas outlet 4 of the fourth oxygen-permeable membrane reactor is connected to the inlet of the second oxygen-permeable membrane reactor. The high-temperature gas outlet 2 of the second oxygen-permeable membrane reactor is connected to the inlet of the first oxygen-permeable membrane reactor. The hydrogen-rich gas outlet of the first oxygen-permeable membrane reactor is connected to the inlet of the first condenser. The high-temperature gas outlet 1 of the first oxygen-permeable membrane reactor is connected to the inlets of the third and fourth oxygen-permeable membrane reactors.

[0010] This invention also claims a method for producing hydrogen by co-producing nitrogen using the system, comprising the following steps:

[0011] (1) Air is introduced into the third oxygen-permeable membrane reactor. Oxygen migrates through the oxygen-permeable membrane to the oxygen side and mixes with fuel and circulating gas. The reaction produces high-temperature gas three, which is drawn out from the third oxygen-permeable membrane reactor. The remaining oxygen-deficient air on the air side of the third oxygen-permeable membrane reactor is introduced into the fourth oxygen-permeable membrane reactor. Oxygen in the oxygen-deficient air migrates through the oxygen-permeable membrane to the oxygen side and mixes with fuel and circulating gas. The reaction produces high-temperature gas four, which is mixed with high-temperature gas three to obtain mixed gas two, which is introduced into the second oxygen-permeable membrane reactor. High-purity nitrogen is obtained on the oxygen-deficient air side of the fourth oxygen-permeable membrane reactor.

[0012] (2) Water vapor is introduced into the second oxygen permeable membrane reactor. Oxygen migrates through the oxygen permeable membrane to the oxygen side and mixes with mixed gas two, and reacts to produce high-temperature gas two. The remaining hydrogen-containing gas on the water vapor side of the second oxygen permeable membrane reactor is mixed with high-temperature gas two to obtain mixed gas one, which is then introduced into the first oxygen permeable membrane reactor.

[0013] (3) Water vapor is introduced into the first oxygen permeable membrane reactor. Oxygen migrates through the oxygen permeable membrane to the oxygen side and mixes with mixed gas 1. The reaction produces high temperature gas 1. Part of the high temperature gas 1 is discharged from the system, and the other part is introduced into the third oxygen permeable membrane reactor and the fourth oxygen permeable membrane reactor as circulating gas. The remaining hydrogen-rich gas on the water vapor side of the first oxygen permeable membrane reactor is introduced into the first condenser to obtain high-purity hydrogen and condensate.

[0014] Preferably, the oxygen-permeable membrane reactor has a tube sheet and / or flat plate structure.

[0015] Preferably, the oxygen-permeable membrane is one or more of the following structures: perovskite, fluorite-perovskite, fluorite-metal, and perovskite-metal.

[0016] Preferably, the oxygen-permeable membrane is one or more of a single-layer membrane, a double-layer membrane, and a hybrid conductor oxygen-permeable membrane.

[0017] Preferably, the oxygen permeable membranes used in the first and second oxygen permeable membrane reactors are fluorite-metal and / or perovskite-metal double-layer oxygen permeable membranes.

[0018] Preferably, the tube diameter of the tube-type oxygen permeable membrane is 1-20 mm, the membrane thickness is 0.1-5 mm, and the tube spacing is 0.5-5 times the tube diameter; the membrane thickness of the flat plate oxygen permeable membrane is 0.1-5 mm, and the membrane spacing is 0.5-25 mm.

[0019] Preferably, the working temperature of the oxygen-permeable membrane reactor is 400-1000℃, the pressure difference across the oxygen-permeable membrane is 0-9MPa, and the pressure inside the membrane cavity is not lower than the pressure outside the membrane cavity.

[0020] Preferably, in step (1), 50-80% of the gas formed after mixing fuel and circulating gas enters the third oxygen-permeable membrane reactor and 20-50% of the gas enters the fourth oxygen-permeable membrane reactor.

[0021] Preferably, in step (2), the volume concentration of hydrogen in the hydrogen-containing gas is 0-40%.

[0022] Preferably, in step (2), the volume concentration of hydrogen in the hydrogen-containing gas is 5-20%.

[0023] Preferably, in step (3), the circulating gas accounts for 10-90% of the volume of the high-temperature gas.

[0024] Preferably, in step (3), the volume concentration of hydrogen in the hydrogen-rich gas is 0-95%.

[0025] Preferably, in step (3), the volume concentration of hydrogen in the hydrogen-rich gas is 50-80%.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) The present invention provides a hydrogen production system and method for co-producing nitrogen, which utilizes the oxygen enrichment characteristics of the oxygen-permeable membrane and the reducing properties of hydrogen and fuel to separate nitrogen in the air and hydrogen and oxygen in water vapor. It can simultaneously produce nitrogen and hydrogen with a purity of over 99%, which greatly improves the economy and system efficiency of the oxygen-permeable membrane hydrogen production technology. Compared with conventional hydrogen production technology, it has the advantages of simple system, low energy consumption, fast start-up, low cost and convenient operation. The operating cost is reduced by about 1 / 3 compared with conventional hydrogen production technology.

[0028] 2) The present invention provides a hydrogen production system and method for co-producing nitrogen. Fuel undergoes incomplete combustion with air in the fourth and third oxygen-permeable membrane reactors to produce high-temperature gas containing CO. The reaction rate of the CO-containing gas mixture is faster than that of the gas containing fuel alone with oxygen. At the same time, mixing the hydrogen-containing gas obtained from the second oxygen-permeable membrane reactor with the high-temperature gas can also effectively improve the reaction rate of the mixture with oxygen in the first oxygen-permeable membrane reactor. Through the cooperation of multiple oxygen-permeable membrane reactors, not only can nitrogen be co-produced, but the process of producing hydrogen by water vapor decomposition can also be greatly accelerated. Compared with the single-stage oxygen-permeable membrane hydrogen production technology, the hydrogen production efficiency can be improved by more than 20%.

[0029] 3) The present invention provides a hydrogen production system and method for co-producing nitrogen. Fuel enters an oxygen-permeable membrane reactor and undergoes an incomplete combustion reaction with oxygen to generate a high-temperature gas containing CO. While consuming oxygen, heat is released, providing heat for the migration of oxygen in the oxygen-permeable membrane reactor. Mixed gas 2 and mixed gas 1 enter the oxygen-permeable membrane reactor and can react rapidly with oxygen separated from water vapor, accelerating the rate of hydrogen production from water vapor decomposition. At the same time, the heat released by the reaction is used to maintain the reaction temperature for hydrogen separation, ensuring the hydrogen production rate. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some schematic diagrams of certain embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 The present invention provides a process flow diagram of a hydrogen production method for co-producing hydrogen.

[0032] In the diagram, R1 is the first oxygen-permeable membrane reactor; R2 is the second oxygen-permeable membrane reactor; R3 is the third oxygen-permeable membrane reactor; R4 is the fourth oxygen-permeable membrane reactor; and C1 is the first condenser. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] The terms "first," "second," etc., are used only for descriptive distinction and should not be interpreted as indicating or implying relative importance. Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be perfectly horizontal, but can be slightly tilted.

[0035] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0037] like Figure 1 As shown, the present invention provides a hydrogen production system for co-producing nitrogen, including a third oxygen-permeable membrane reactor R3, a fourth oxygen-permeable membrane reactor R4, a second oxygen-permeable membrane reactor R2, a first oxygen-permeable membrane reactor R1, and a first condenser C1;

[0038] The oxygen-deficient air outlet of the third oxygen-permeable membrane reactor R3 is connected to the inlet of the fourth oxygen-permeable membrane reactor R4. The high-temperature gas outlet of the third oxygen-permeable membrane reactor R3 is connected to the inlet of the second oxygen-permeable membrane reactor R2. The high-temperature gas outlet of the fourth oxygen-permeable membrane reactor R4 is connected to the inlet of the second oxygen-permeable membrane reactor R2. The high-temperature gas outlet of the second oxygen-permeable membrane reactor R2 is connected to the inlet of the first oxygen-permeable membrane reactor R1. The hydrogen-rich gas outlet of the first oxygen-permeable membrane reactor R1 is connected to the inlet of the first condenser C1. The high-temperature gas outlet of the first oxygen-permeable membrane reactor R1 is connected to the inlets of the third oxygen-permeable membrane reactor R3 and the fourth oxygen-permeable membrane reactor R4.

[0039] The present invention also provides a method for producing hydrogen by co-producing nitrogen using the system, comprising the following steps:

[0040] (1) Air is introduced into the third oxygen-permeable membrane reactor R3. Oxygen migrates through the oxygen-permeable membrane to the oxygen side and mixes with fuel and circulating gas, producing high-temperature gas three, which is drawn out from the third oxygen-permeable membrane reactor R3. The remaining oxygen-deficient air on the air side of the third oxygen-permeable membrane reactor R3 is introduced into the fourth oxygen-permeable membrane reactor R4. Oxygen in the oxygen-deficient air migrates through the oxygen-permeable membrane to the oxygen side and mixes with fuel and circulating gas, producing high-temperature gas four, which is mixed with high-temperature gas three to obtain mixed gas two, which is introduced into the second oxygen-permeable membrane reactor R2. High-purity nitrogen is obtained on the oxygen-deficient air side of the fourth oxygen-permeable membrane reactor R4.

[0041] Specifically, in step (1), 50-80% of the volume of the gas formed after mixing the fuel and the circulating gas enters the third oxygen-permeable membrane reactor R3, which can be 50%, 60%, 70%, or 80%; and 20-50% of the volume enters the fourth oxygen-permeable membrane reactor R5, which can be 20%, 30%, 40%, or 50%.

[0042] (2) Water vapor is introduced into the second oxygen permeable membrane reactor R2. Oxygen migrates through the oxygen permeable membrane to the oxygen side and mixes with mixed gas two, and reacts to produce high-temperature gas two. The remaining hydrogen-containing gas on the water vapor side of the second oxygen permeable membrane reactor R2 is mixed with high-temperature gas two to obtain mixed gas one, which is then introduced into the first oxygen permeable membrane reactor R1.

[0043] Specifically, in step (2), the volume concentration of hydrogen in the hydrogen-containing gas is 0-40%, which can be 0%, 10%, 20%, 30%, or 40%, and is preferably 5-20%.

[0044] (3) Water vapor is introduced into the first oxygen permeable membrane reactor R1. Oxygen migrates through the oxygen permeable membrane to the oxygen side and mixes with mixed gas 1. The reaction produces high temperature gas 1. Part of the high temperature gas 1 is discharged from the system, and the other part is introduced into the third oxygen permeable membrane reactor R3 and the fourth oxygen permeable membrane reactor R4 as circulating gas. The remaining hydrogen-rich gas on the water vapor side of the first oxygen permeable membrane reactor R1 is introduced into the first condenser C1 to obtain high-purity hydrogen and condensate.

[0045] Specifically, in step (3), the circulating gas accounts for 10% to 90% of the volume of the high-temperature gas, which can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.

[0046] Specifically, in step (3), the volume concentration of hydrogen in the hydrogen-rich gas is 0-95%, which can be 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%, preferably 50-80%.

[0047] Specifically, the oxygen-permeable membrane reactor has a tube sheet and / or flat plate structure.

[0048] Specifically, the oxygen-permeable membrane is one or more of the following structures: perovskite, fluorite-perovskite, fluorite-metal, and perovskite-metal.

[0049] Specifically, the oxygen-permeable membrane is one or more of the following: single-layer membrane, double-layer membrane, and mixed conductor oxygen-permeable membrane.

[0050] Specifically, the oxygen permeable membranes used in the first oxygen permeable membrane reactor R1 and the second oxygen permeable membrane reactor R2 are fluorite-metal and / or perovskite-metal double-layer oxygen permeable membranes.

[0051] More specifically, the diameter of the tubes in the tube-plate type oxygen-permeable membrane is 1-20mm, which can be 1mm, 5mm, 10mm, 15mm, or 20mm; the membrane thickness is 0.1-5mm, which can be 0.1mm, 0.5mm, 1mm, 2mm, 3mm, 4mm, or 5mm; and the tube spacing is 0.5-5 times the tube diameter, which can be 0.5 times the tube diameter, 1 times the tube diameter, 2 times the tube diameter, 3 times the tube diameter, 4 times the tube diameter, or 5 times the tube diameter.

[0052] More specifically, the thickness of the flat-sheet oxygen-permeable membrane is 0.1–5 mm, which can be 0.1 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm; the membrane spacing is 0.5–25 mm, which can be 0.5 mm, 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, or 25 mm.

[0053] In an optional embodiment, the operating temperature of the oxygen-permeable membrane reactor is 400–1000℃, which can be 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, or 1000℃; the pressure difference across the oxygen-permeable membrane is 0–9MPa, which can be 0MPa, 1MPa, 3MPa, 6MPa, or 9MPa, and the pressure inside the membrane cavity is not lower than the pressure outside the membrane cavity.

[0054] The present invention will be further described below through specific embodiments.

[0055] Example 1

[0056] A hydrogen production system that co-produces nitrogen includes a third oxygen-permeable membrane reactor R3, a fourth oxygen-permeable membrane reactor R4, a second oxygen-permeable membrane reactor R2, a first oxygen-permeable membrane reactor R1, and a first condenser C1.

[0057] The oxygen-deficient air outlet of the third oxygen-permeable membrane reactor R3 is connected to the inlet of the fourth oxygen-permeable membrane reactor R4. The high-temperature gas outlet of the third oxygen-permeable membrane reactor R3 is connected to the inlet of the second oxygen-permeable membrane reactor R2. The high-temperature gas outlet of the fourth oxygen-permeable membrane reactor R4 is connected to the inlet of the second oxygen-permeable membrane reactor R2. The high-temperature gas outlet of the second oxygen-permeable membrane reactor R2 is connected to the inlet of the first oxygen-permeable membrane reactor R1. The hydrogen-rich gas outlet of the first oxygen-permeable membrane reactor R1 is connected to the inlet of the first condenser C1. The high-temperature gas outlet of the first oxygen-permeable membrane reactor R1 is connected to the inlets of the third oxygen-permeable membrane reactor R3 and the fourth oxygen-permeable membrane reactor R4.

[0058] Example 2

[0059] A method for producing hydrogen by co-producing nitrogen includes the following steps:

[0060] (1) 20°C air is introduced into the third oxygen-permeable membrane reactor R3. Oxygen migrates through the oxygen-permeable membrane to the oxygen side and mixes with hydrocarbon fuel and circulating gas. The reaction produces 900°C high-temperature gas three, which is drawn out from the third oxygen-permeable membrane reactor R3. The remaining 900°C oxygen-deficient air on the air side of the third oxygen-permeable membrane reactor R3 is introduced into the fourth oxygen-permeable membrane reactor R4. Oxygen in the oxygen-deficient air migrates through the oxygen-permeable membrane to the oxygen side and mixes with hydrocarbon fuel and circulating gas. The reaction produces 900°C high-temperature gas four, which is mixed with high-temperature gas three to obtain mixed gas two, which is introduced into the second oxygen-permeable membrane reactor R2. The oxygen-deficient air side of the fourth oxygen-permeable membrane reactor R4 obtains nitrogen gas with a purity of over 99% at 900°C, which is cooled to 50°C by heat exchange and collected.

[0061] (2) Water vapor is introduced into the second oxygen permeable membrane reactor R2. Oxygen migrates through the oxygen permeable membrane to the oxygen side and mixes with mixed gas two, and reacts to produce high-temperature gas two. The remaining hydrogen-containing gas with a hydrogen volume concentration of 15% on the water vapor side of the second oxygen permeable membrane reactor R2 is mixed with high-temperature gas two to obtain mixed gas one, which is then introduced into the first oxygen permeable membrane reactor R1.

[0062] (3) Water vapor is introduced into the first oxygen permeable membrane reactor R1. Oxygen migrates through the oxygen permeable membrane to the oxygen side and mixes with mixed gas 1. The reaction produces high-temperature gas 1 at 900°C. 30% of the volume of high-temperature gas 1 is discharged from the system, and 70% is used as circulating gas. 70% of the volume of circulating gas is introduced into the third oxygen permeable membrane reactor R3, and 30% is introduced into the fourth oxygen permeable membrane reactor R4. The remaining hydrogen-rich gas with a volume concentration of 95% on the water vapor side of the first oxygen permeable membrane reactor R1 is introduced into the first condenser C1 to obtain high-purity hydrogen and condensate.

[0063] Specifically, the oxygen-permeable membrane reactors R1 and R2 use a perovskite-metallic double-layer structure with a tube-plate configuration. The tubes have a diameter of 10 mm, a thickness of 2 mm, and a spacing of 1.5 times the tube diameter. The pressure difference across the tubes is 3 MPa. The oxygen-permeable membrane reactors R3 and R4 use a perovskite-based mixed conductor membrane, stacked in a flat plate structure. The flat plate membrane has a thickness of 1 mm, a spacing of 1.5 mm, and a pressure difference of 2.5 MPa.

[0064] Comparative Example 1

[0065] A method for producing hydrogen by co-producing nitrogen includes the following steps:

[0066] (1) 20°C air is introduced into the third oxygen-permeable membrane reactor R3. Oxygen migrates through the oxygen-permeable membrane to the oxygen side and mixes with hydrocarbon fuel and circulating gas. The reaction produces 900°C high-temperature gas three, which is drawn out from the third oxygen-permeable membrane reactor R3. The remaining 900°C oxygen-deficient air on the air side of the third oxygen-permeable membrane reactor R3 is introduced into the fourth oxygen-permeable membrane reactor R4. Oxygen in the oxygen-deficient air migrates through the oxygen-permeable membrane to the oxygen side and mixes with hydrocarbon fuel and circulating gas. The reaction produces 900°C high-temperature gas four, which is mixed with high-temperature gas three to obtain mixed gas two, which is introduced into the first oxygen-permeable membrane reactor R1. The oxygen-deficient air side of the fourth oxygen-permeable membrane reactor R4 obtains nitrogen gas with a purity of over 99% at 900°C, which is cooled to 50°C by heat exchange and collected.

[0067] (2) Water vapor is introduced into the first oxygen permeable membrane reactor R1. Oxygen migrates through the oxygen permeable membrane to the oxygen side and mixes with mixed gas 2. The reaction produces a high-temperature gas 1 at 900°C. 30% of the volume of high-temperature gas 1 is discharged from the system, and 70% is used as circulating gas. 70% of the volume of circulating gas is introduced into the third oxygen permeable membrane reactor R3, and 30% is introduced into the fourth oxygen permeable membrane reactor R4. The remaining hydrogen-rich gas with a volume concentration of 95% on the water vapor side of the first oxygen permeable membrane reactor R1 is introduced into the first condenser C1 to obtain high-purity hydrogen and condensate.

[0068] Specifically, the oxygen-permeable membrane reactor R1 uses a perovskite-metallic double-layer membrane with a tube-plate structure. The membrane tube diameter is 10 mm, the membrane thickness is 2 mm, the tube spacing is 1.5 times the tube diameter, and the pressure difference across the membrane tubes is 3 MPa. The oxygen-permeable membrane reactors R3 and R4 use perovskite-based mixed conductor membranes stacked in a flat plate structure. The flat plate membrane has a thickness of 1 mm, a membrane spacing of 1.5 mm, and a pressure difference across the membrane is 2.5 MPa.

[0069] Comparative Example 2

[0070] A method for producing hydrogen includes the following steps:

[0071] (1) 20°C air is introduced into the third oxygen-permeable membrane reactor R3. Oxygen migrates through the oxygen-permeable membrane to the oxygen side and mixes with hydrocarbon fuel and circulating gas. The reaction produces 900°C high-temperature gas three, which is drawn out from the third oxygen-permeable membrane reactor R3. The remaining 900°C oxygen-deficient air on the air side of the third oxygen-permeable membrane reactor R3 is introduced into the fourth oxygen-permeable membrane reactor R4. Oxygen in the oxygen-deficient air migrates through the oxygen-permeable membrane to the oxygen side and mixes with hydrocarbon fuel and circulating gas. The reaction produces 900°C high-temperature gas four, which is mixed with high-temperature gas three to obtain mixed gas two, which is introduced into the first oxygen-permeable membrane reactor R1. The oxygen-deficient air side of the fourth oxygen-permeable membrane reactor R4 obtains nitrogen gas with a purity of over 99% at 900°C, which is cooled to 50°C by heat exchange and collected.

[0072] (2) Water vapor is introduced into the first oxygen-permeable membrane reactor R1. Oxygen migrates to the oxygen side through the oxygen-permeable membrane. Hydrogen fuel gas is introduced into the oxygen side of the first oxygen-permeable membrane reactor R1 and reacts with oxygen to produce a high-temperature gas at 900°C. 30% of the volume of the high-temperature gas is discharged from the system, and 70% is used as circulating gas. The circulating gas is introduced into the first oxygen-permeable membrane reactor R1. The remaining hydrogen-rich gas with a volume concentration of 95% on the water vapor side of the first oxygen-permeable membrane reactor R1 is introduced into the first condenser C1 to obtain high-purity hydrogen and condensate.

[0073] Specifically, the oxygen permeable membrane of the first oxygen permeable membrane reactor R1 is a perovskite-metallic double-layer oxygen permeable membrane with a tube sheet structure. The membrane tube diameter is 10 mm, the membrane thickness is 2 mm, the tube spacing is 1.5 times the tube diameter, and the pressure difference on both sides of the oxygen permeable membrane tube is 3 MPa.

[0074] In the embodiments, the condensate can be reused to generate water vapor. The heat required to generate water vapor can be obtained by optimizing hydrogen-rich gas condensation, air heating, and high-temperature nitrogen cooling. The above heat exchange process can be arbitrarily combined and optimized according to the temperature gradient, and is not limited to the listed heat exchange methods.

[0075] The hydrogen production rates and products of Examples 1-2 and Comparative Examples 1-2 are shown in Table 1. The hydrogen production rate is calculated based on the oxygen permeable membrane area and the water vapor side area.

[0076] Table 1 Hydrogen production rate and products

[0077]

[0078]

[0079] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A hydrogen production system for co-production of nitrogen, characterized by, The system comprises a third oxygen permeable membrane reactor (R3), a fourth oxygen permeable membrane reactor (R4), a second oxygen permeable membrane reactor (R2), a first oxygen permeable membrane reactor (R1), and a first condenser (C1). The oxygen-depleted air outlet of the third oxygen permeable membrane reactor (R3) is in communication with the inlet of the fourth oxygen permeable membrane reactor (R4), the high-temperature gas three outlet of the third oxygen permeable membrane reactor (R3) is in communication with the inlet of the second oxygen permeable membrane reactor (R2), the high-temperature gas four outlet of the fourth oxygen permeable membrane reactor (R4) is in communication with the inlet of the second oxygen permeable membrane reactor (R2), the high-temperature gas two outlet of the second oxygen permeable membrane reactor (R2) is in communication with the inlet of the first oxygen permeable membrane reactor (R1), the hydrogen-rich gas outlet of the first oxygen permeable membrane reactor (R1) is in communication with the inlet of the first condenser (C1), and the high-temperature gas one outlet of the first oxygen permeable membrane reactor (R1) is in communication with the inlets of the third oxygen permeable membrane reactor (R3) and the fourth oxygen permeable membrane reactor (R4). The method for producing hydrogen and nitrogen gas by using the system comprises the following steps: (1) introducing air into the third oxygen permeable membrane reactor (R3), oxygen in the air migrates to the oxygen side through the oxygen permeable membrane and is mixed with fuel and circulating gas to produce high-temperature gas three, which is then introduced out of the third oxygen permeable membrane reactor (R3); the oxygen-depleted air remaining in the air side of the third oxygen permeable membrane reactor (R3) is introduced into the fourth oxygen permeable membrane reactor (R4), oxygen in the oxygen-depleted air migrates to the oxygen side through the oxygen permeable membrane and is mixed with fuel and circulating gas to produce high-temperature gas four, which is then mixed with high-temperature gas three to obtain mixed gas two, which is then introduced into the second oxygen permeable membrane reactor (R2); high-purity nitrogen gas is obtained from the oxygen-depleted air side of the fourth oxygen permeable membrane reactor (R4); (2) introducing water vapor into the second oxygen permeable membrane reactor (R2), oxygen migrates to the oxygen side through the oxygen permeable membrane and is mixed with mixed gas two to produce high-temperature gas two; the hydrogen-containing gas remaining in the water vapor side of the second oxygen permeable membrane reactor (R2) is mixed with high-temperature gas two to obtain mixed gas one, which is then introduced into the first oxygen permeable membrane reactor (R1); (3) introducing water vapor into the first oxygen permeable membrane reactor (R1), oxygen migrates to the oxygen side through the oxygen permeable membrane and is mixed with mixed gas one to produce high-temperature gas one, part of which is discharged from the system, and the other part is introduced into the third oxygen permeable membrane reactor (R3) and the fourth oxygen permeable membrane reactor (R4) as circulating gas; the hydrogen-rich gas remaining in the water vapor side of the first oxygen permeable membrane reactor (R1) is introduced into the first condenser (C1) to obtain high-purity hydrogen gas and condensed water.

2. The hydrogen production system for co-production of nitrogen gas according to claim 1, wherein, The oxygen permeable membrane reactor is of a tube-plate type and / or a flat-plate type structure.

3. The hydrogen production system for coproduction of nitrogen gas according to claim 1, wherein The oxygen permeable membrane is one or more of perovskite type, fluorite-perovskite type, fluorite-metal type, and perovskite-metal type structure.

4. The hydrogen co-product nitrogen system of claim 1, wherein, The oxygen permeable membrane is one or more of single-layer membrane, double-layer membrane, and mixed conductor oxygen permeable membrane.

5. The hydrogen co-product nitrogen generation system of claim 1, wherein, The oxygen permeable membrane used in the first oxygen permeable membrane reactor (R1) and the second oxygen permeable membrane reactor (R2) is a fluorite-metal type and / or perovskite-metal type double-layer oxygen permeable membrane.

6. The hydrogen co-product nitrogen generation system of claim 1, wherein, The tube plate type oxygen permeable membrane has a tube diameter of 1-20 mm, a membrane thickness of 0.1-5 mm, and a tube spacing of 0.5-5 times the tube diameter; the flat plate type oxygen permeable membrane has a membrane thickness of 0.1-5 mm and a membrane spacing of 0.5-25 mm.

7. The hydrogen co-product nitrogen generation system of claim 1, wherein, The oxygen permeable membrane reactor has a working temperature of 400-1000 DEG C, a pressure difference between the two sides of the oxygen permeable membrane of 0-9 MPa, and an internal pressure of the membrane cavity not lower than the external pressure of the membrane cavity.

8. The hydrogen co-product nitrogen generation system of claim 1, wherein, In step (1), 50-80% of the volume of the gas formed by mixing the fuel and the circulating gas enters the third oxygen permeable membrane reactor (R3), and 20-50% of the volume of the gas enters the fourth oxygen permeable membrane reactor (R4).

9. The hydrogen co-product nitrogen generation system of claim 1, wherein, In step (2), the volume concentration of hydrogen in the hydrogen-containing gas is >0 and ≤40%.

10. The hydrogen co-product nitrogen generation system of claim 1, wherein, In step (3), the circulating gas accounts for 10-90% of the volume of the high-temperature gas.

11. The hydrogen co-product nitrogen gas system of claim 1, wherein, In step (3), the volume concentration of hydrogen in the hydrogen-rich gas is >0 and ≤95%.

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