A fuel chemical chain hydrogen production system and method

Abstract

The present invention relates to a fuel chemical looping hydrogen production system and method, comprising two identical chemical looping combustion reactors, each comprising an outer tube and an inner tube coaxially arranged with the outer tube, the inner tube being filled with a first oxygen carrier, and the interlayer between the outer and inner tubes being filled with a second oxygen carrier; the upper end of the inner tube being connected to a water vapor inlet pipe and a fuel inlet pipe, and the lower end of the inner tube being connected to a gas outlet pipe. When water vapor is introduced into the first chemical looping combustion reactor to undergo an oxidation reaction of the oxygen carrier with the reduced oxygen carrier, the second chemical looping combustion reactor is introduced into the fuel to undergo a reduction reaction of the oxygen carrier with the oxidized oxygen carrier. The fuel chemical looping hydrogen production system of the present invention has a simple process, a compact reactor, and is easily miniaturized, and can efficiently produce pure hydrogen from gaseous or liquid fuels.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel hydrogen production, and in particular to a fuel chemical chain hydrogen production technology for efficiently producing hydrogen from gaseous or liquid fuel that can be directly used in a proton exchange membrane fuel cell (PEMFC) pure hydrogen stack. Background Art

[0002] Hydrogen energy and fuel cells are a key development direction in the field of new energy technology. Efficiently producing pure hydrogen from various fossil fuels, including natural gas, diesel, kerosene, and gasoline, various coal gases, including coke oven gas, and various biomass gases, such as biogas, is a key research topic. Among various fuel cells, PEMFC (PEMFC) has attracted considerable attention due to its potential applications in fuel cell vehicles (FCVs) and distributed combined heat and power (CHP) systems. To date, PEMFCs used in FCVs typically utilize pure hydrogen stacks (H2-PEMFCs) fueled by pure hydrogen, while PEMFCs used in distributed CHP systems typically utilize reformed gas stacks (reformed gas-PEMFCs) fueled by reformed gas (derived from steam reforming, autothermal reforming, or partial oxidation reforming of hydrocarbons, containing at least 20% CO2). Compared with reformed gas-PEMFC, H2-PEMFC has the advantages of high power generation efficiency, low cost and high power density. Therefore, efficiently producing pure hydrogen from fuels such as natural gas and then forming a fuel-H2-PEMFC distributed cogeneration system with H2-PEMFC will have good energy-saving and economic benefits.

[0003] Taking natural gas as an example, commonly used processes for producing pure hydrogen from natural gas include steam reforming + CO2 steam shift + PSA, steam reforming + CO2 steam shift + CO2 chemical absorption, and steam reforming + CO2 steam shift + CO2 organic solvent absorption. Due to the complexity, high energy consumption, and difficulty in miniaturization of PSA, CO2 chemical absorption, and CO2 organic solvent absorption processes, they are not suitable for natural gas-H2-PEMFC distributed cogeneration systems.

[0004] In recent years, chemical looping hydrogen production from coal gasification gas, featuring zero-energy CO2 capture, has begun to attract research attention. This chemical looping hydrogen production process involves three independent steps: the reaction of FeO with water vapor to produce Fe3O4 and hydrogen; the reaction of Fe3O4 with air to produce Fe2O3; and the reaction of Fe2O3 with fuel to produce FeO and CO2 + H2O. This requires three reactors to be switched in a continuous manner to obtain hydrogen, making the system very complex. Furthermore, the system emits two high-temperature flue gases (the flue gas from the reaction of Fe3O4 with air and the flue gas from the reaction of Fe2O3 with fuel), making heat recovery difficult and reducing hydrogen production efficiency. Therefore, existing chemical looping hydrogen production processes are not suitable for natural gas-H2-PEMFC distributed cogeneration systems. Summary of the Invention

[0005] To address the aforementioned challenges of the existing technologies, the present invention provides a fuel chemical looping hydrogen production system that can efficiently produce pure hydrogen from a variety of fuels. Specifically, it provides a fuel chemical looping hydrogen production system based on a combination of steam reforming and chemical looping combustion. Furthermore, this fuel chemical looping hydrogen production system is not only suitable for large-scale hydrogen production but also easily miniaturized, making it highly suitable for fuel-H2-PEMFC distributed combined heat and power systems.

[0006] The purpose of the present invention and the solution to the technical problem are achieved by adopting the following technical solutions.

[0007] A fuel chemical chain hydrogen production system proposed in the present invention includes two completely identical chemical chain combustion reactors, wherein the chemical chain combustion reactor includes an outer tube and an inner tube coaxially arranged with the outer tube, the inner tube is filled with a first oxygen carrier, and the interlayer between the outer tube and the inner tube is filled with a second oxygen carrier; the upper end of the inner tube is connected to a water vapor inlet pipe and a fuel inlet pipe, and the lower end of the inner tube is connected to a gas outlet pipe, the gas outlet pipe is connected to the hydrogen outlet pipe and the reduction reaction product gas connecting pipe through a third three-way valve, and the other end of the reduction reaction product gas connecting pipe is connected to the lower end of the interlayer; the upper end of the interlayer is connected to the combustion flue gas outlet pipe, and the lower end of the interlayer is connected to the combustion air inlet pipe; the water vapor inlet pipes of the two chemical chain combustion reactors are connected through the first three-way valve, the fuel inlet pipe is connected through the second three-way valve, and the combustion air inlet pipe is connected through the fifth three-way valve. For large-scale hydrogen production, a shell-and-tube reactor may be used, wherein the inside of the tubes of the tube bundle, i.e., the tube side, is filled with a first oxygen carrier, and the outside of the tube bundle, i.e., the shell side, is filled with a second oxygen carrier.

[0008] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0009] Preferably, in the aforementioned fuel chemical chaining hydrogen production system, the fuel is a gaseous or liquid fuel, the first oxygen carrier is an oxygen carrier having iron oxide as a main active ingredient, and the second oxygen carrier is an iron-based oxygen carrier, a copper-based oxygen carrier, a nickel-based oxygen carrier, a calcium-based oxygen carrier, a manganese-based oxygen carrier, or a mixture of two or more thereof. The second oxygen carrier may also be replaced by a catalytic combustion catalyst.

[0010] Preferably, in the aforementioned fuel chemical chaining hydrogen production system, water vapor is added to the fuel, and a steam reforming catalyst is filled above the first oxygen carrier filling layer to perform a steam reforming reaction of the fuel and a CO water gas shift reaction. The steam reforming catalyst can be a Ni-based reforming catalyst or a Ru-based reforming catalyst.

[0011] Preferably, in the aforementioned fuel chemical chaining hydrogen production system, a desulfurizer is filled above the filling layer of the steam reforming catalyst to perform a desulfurization reaction of the fuel. The desulfurizer can be iron oxide or copper oxide desulfurizer.

[0012] Preferably, in the aforementioned fuel chemical chain hydrogen production system, a methanation reactor is provided on the hydrogen outlet pipe, and the methanation reactor is filled with a methanation catalyst.

[0013] Preferably, the aforementioned fuel chemical chain hydrogen production system is further provided with a flue gas heat exchanger between flue gas and water on the flue gas pipeline, and the generated water vapor is used as the water vapor required for hydrogen production by the fuel chemical chain hydrogen production system.

[0014] Preferably, the aforementioned fuel chemical chain hydrogen production system is further provided with a first hydrogen heat exchanger between hydrogen and water on the hydrogen pipeline, and the generated water vapor is used as the water vapor required for hydrogen production by the fuel chemical chain hydrogen production system.

[0015] Preferably, in the aforementioned fuel chemical chain hydrogen production system, a second hydrogen heat exchanger for hydrogen and water is further provided on the hydrogen pipeline at the outlet of the methanation reactor, and the generated water vapor is used as the water vapor required for hydrogen production by the fuel chemical chain hydrogen production system.

[0016] Preferably, the aforementioned fuel chemical chain hydrogen production system also includes a second type of absorption heat pump subsystem, which includes a generator, a condenser, a first evaporator, a first absorber and a solution heat exchanger, and the generator includes a solution spraying device and a generator heat exchanger; the condenser includes a condensing heat exchanger, the inlet of the condensing heat exchanger is connected to the first water inlet pipe, and the outlet of the condensing heat exchanger is connected to the first water vapor outlet pipe; the first evaporator includes a working fluid spraying device and an evaporation heat exchanger; the first absorber includes a solution spraying device and a first absorption heat exchanger, the inlet of the first absorption heat exchanger is connected to the second water inlet pipe, and the outlet of the first absorption heat exchanger is connected to the second water vapor outlet pipe; the water vapor generated by the condensing heat exchanger and the first absorption heat exchanger is used as the water vapor required for hydrogen production by the fuel chemical chain hydrogen production system.

[0017] Preferably, in the aforementioned fuel chemical chain hydrogen production system, the generating heat exchanger includes a first generating heat exchanger and a second generating heat exchanger; the evaporating heat exchanger includes a first evaporating heat exchanger and a second evaporating heat exchanger; the inlet of the first generating heat exchanger is connected to the flue gas outlet pipe, the outlet of the first generating heat exchanger is connected to the inlet of the first evaporating heat exchanger, the inlet of the second generating heat exchanger is connected to the hydrogen outlet pipe, the outlet of the second generating heat exchanger is connected to the inlet of the methanation reactor, and the outlet of the methanation reactor is connected to the inlet of the second evaporating heat exchanger.

[0018] Preferably, the aforementioned fuel chemical chain hydrogen production system also includes a first type of absorption heat pump subsystem or absorption refrigeration subsystem, the first type of absorption heat pump subsystem or absorption refrigeration subsystem includes a generator, a condenser, a second evaporator, a second absorber and a solution heat exchanger, the generator includes a solution spray device and a generator heat exchanger; the condenser includes a condensation heat exchanger, the inlet of the condensation heat exchanger is connected to the first water inlet pipe, and the outlet of the condensation heat exchanger is connected to the first water vapor outlet pipe; the second evaporator includes a working fluid spray device and a third evaporation heat exchanger; the second absorber includes a solution spray device and a second absorption heat exchanger; the water vapor generated by the condensation heat exchanger is used as the water vapor required for hydrogen production in the fuel chemical chain hydrogen production system.

[0019] Preferably, in the aforementioned fuel chemical chain hydrogen production system, the heat exchanger includes a first heat exchanger and a second heat exchanger; the inlet of the first heat exchanger is connected to the flue gas outlet pipe, the inlet of the second heat exchanger is connected to the hydrogen outlet pipe, and the outlet of the second heat exchanger is connected to the inlet of the methanation reactor.

[0020] The purpose of the present invention and the solution to the technical problem are also achieved by adopting the following technical solutions.

[0021] According to a fuel chemical looping hydrogen production method proposed in the present invention, a fuel chemical looping hydrogen production system according to any one of the preceding claims is used. The hydrogen production method includes: when the first chemical looping combustion reactor of the two chemical looping combustion reactors introduces water vapor through the water vapor introduction pipe to carry out an oxidation reaction of the oxygen carrier with a reduced oxygen carrier to generate hydrogen, and the hydrogen is discharged through the hydrogen outlet pipe, the second chemical looping combustion reactor introduces fuel or a mixture of fuel and water vapor through the fuel or fuel and water vapor introduction pipe to carry out a reduction reaction of the oxygen carrier with an oxidized oxygen carrier to generate a reduction reaction product gas, the reduction reaction product gas is introduced into the interlayer through the reduction reaction product gas connecting pipe, and combustion air is introduced into the interlayer through the combustion air introduction pipe to carry out a chemical looping combustion reaction of the reduction reaction product gas, wherein the chemical looping combustion reaction provides heat for the reduction reaction of the oxidized oxygen carrier;

[0022] When the oxidation reaction of the reduced oxygen carrier in the first chemical looping combustion reactor is completed, by switching the 1st to 5th three-way valves, the first chemical looping combustion reactor performs the reduction reaction of the oxidized oxygen carrier and the chemical looping combustion reaction of the reduction reaction product gas, and the second chemical looping combustion reactor performs the oxidation reaction of the reduced oxygen carrier.

[0023] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0024] Preferably, in the aforementioned fuel chemical looping hydrogen production method, when the oxidation reaction of the reduced oxygen carrier in the first chemical looping combustion reactor is completed, the first and second three-way valves are first switched to allow the first chemical looping combustion reactor to start the reduction reaction of the oxidized oxygen carrier and the chemical looping combustion reaction of the reduction reaction product gas, and the second chemical looping combustion reactor to start the oxidation reaction of the reduced oxygen carrier. After time t, the third to fifth three-way valves are switched.

[0025] Preferably, in the aforementioned method for producing hydrogen through a fuel chemical chain, the time t is 5 to 30 seconds.

[0026] Preferably, in the aforementioned fuel chemical chain hydrogen production method, the oxidation reaction temperature of the reduced oxygen carrier is 700-850°C; the reduction reaction temperature of the oxidized oxygen carrier is 700-850°C; and the combustion reaction temperature of the reduction reaction product gas is 850-1000°C.

[0027] Preferably, in the aforementioned fuel chemical chain hydrogen production method, the steam reforming reaction temperature is 450-750°C, and the water-to-carbon ratio is 0.5-2.0; or, the desulfurization reaction temperature is 100-450°C; and the methanation reaction temperature is 150-400°C.

[0028] Preferably, in the aforementioned fuel chemical chain hydrogen production method, the high-temperature part of the flue gas waste heat and the high-temperature part of the hydrogen waste heat are used as the driving heat source of the second-type absorption heat pump subsystem generator, and the low-temperature part of the flue gas waste heat and the low-temperature part of the hydrogen waste heat are used as the low-temperature heat source of the second-type absorption heat pump subsystem evaporator.

[0029] Preferably, the aforementioned fuel chemical chain hydrogen production method uses the high-temperature portion of the flue gas waste heat and the high-temperature portion of the hydrogen waste heat as the driving heat source of the first-type absorption heat pump subsystem or the absorption refrigeration subsystem generator for refrigeration or combined heat and cold supply, and uses low-grade thermal energy such as air source, ground source, water source, industrial waste heat, solar energy, geothermal energy, etc. as the low-temperature heat source of the second evaporator for heating.

[0030] The second type absorption heat pump subsystem, the first type absorption heat pump or the refrigeration subsystem uses water as the working fluid and uses one or a mixture of two or more of LiBr, LiCl, LiNO3, CaCl2 or KNO3 as the absorbent.

[0031] By means of the above technical solution, the fuel chemical chain hydrogen production system and method of the present invention have at least the following advantages:

[0032] (1) As a system for producing pure hydrogen from fuel, the fuel chemical chain hydrogen production system of the present invention has a simple process, a simple and compact reactor structure, is easy to miniaturize, and has high hydrogen production efficiency.

[0033] (2) Fe3O4 oxidizes the fuel at temperatures above 700°C, rendering the pollutants in the fuel harmless, thereby reducing the emission of atmospheric pollutants. For example, nitrogen compounds such as NH3, organic amines, and cyanide contained in blast furnace gas are converted into nitrogen, water, and carbon dioxide; sulfides such as H2S and organic sulfides are converted into iron sulfide; and VOCs such as benzene, xylene, and naphthalene are converted into water and carbon dioxide.

[0034] (3) By adding water vapor to the fuel, carbon deposition during the reaction between the fuel and Fe3O4 is effectively suppressed.

[0035] (4) By organically combining steam reforming and chemical chaining hydrogen production, the steam reforming reaction converts the hydrocarbon fuel into CO and H2, which have stronger reducing power, before the hydrocarbon fuel reacts with Fe3O4. This significantly reduces the temperature required to reduce Fe3O4 to FeO, significantly widens the reduction reaction temperature window, avoids sintering of the oxygen carrier, and extends the service life of the oxygen carrier. Furthermore, CO and H2 can further reduce a portion of FeO to Fe, thereby increasing the ability of the first oxygen carrier to generate H2.

[0036] (5) The steam reforming reaction of the fuel is a highly endothermic reaction. By filling the upper part of the inner tube with a steam reforming catalyst, the reaction gas of the steam reforming reaction forms a countercurrent heat exchange with the combustion flue gas, significantly reducing the outlet temperature of the combustion flue gas, thereby further improving the hydrogen production efficiency.

[0037] (6) When switching between two chemical looping combustion reactors, first switch the first and second three-way valves, and then switch the third to fifth three-way valves after 5 to 30 seconds. This not only increases the amount of hydrogen obtained, thereby improving hydrogen production efficiency, but also reduces the amount of impurities such as CO2 and CO mixed into the hydrogen.

[0038] (7) A methanation reactor is installed on the hydrogen outlet pipe to convert the small amount of CO2 and CO mixed into the hydrogen during switching into CH4 which is harmless to the H2-PEMFC stack.

[0039] (8) A flue gas heat exchanger for flue gas and water is installed on the flue gas pipeline, and a hydrogen heat exchanger for hydrogen and water is installed on the hydrogen pipeline. The waste heat of the flue gas and hydrogen is used to generate the water vapor required by the fuel chemical chain hydrogen production system, thereby further improving the hydrogen production efficiency.

[0040] (9) By setting up a second type of absorption heat pump subsystem, high-grade flue gas waste heat and hydrogen waste heat are used in a cascade manner, thereby reducing the system's This reduces losses and improves the energy utilization efficiency of the system. Specifically, by using the high-temperature portion of the flue gas and hydrogen waste heat as the driving heat source for the heat pump subsystem generator, and the low-temperature portion of the flue gas and hydrogen waste heat as the low-temperature heat source for the heat pump subsystem evaporator, the low-temperature waste heat of the flue gas and hydrogen, which would otherwise be too low-quality to serve as a heat source for the water vapor required by the fuel chemical looping hydrogen production system, is converted into a heat source for the water vapor required by the fuel chemical looping hydrogen production system, further improving hydrogen production efficiency.

[0041] (10) By setting up a first-class absorption heat pump or absorption refrigeration subsystem, high-quality flue gas waste heat and hydrogen waste heat are used in a cascade manner, thereby reducing the system's This reduces energy losses and improves the system's energy efficiency. Specifically, by using the high-temperature portion of flue gas and hydrogen waste heat as the driving heat source for the heat pump subsystem generator to generate cooling or combined heat and cooling, and by using locally available low-grade thermal energy as the low-temperature heat source for heating the second evaporator, hydrogen can be produced while providing combined heat and cooling. Furthermore, by combining PEMFC stacks to form a distributed fuel cell power station, a highly efficient distributed combined cooling, heating, and power system can be realized.

[0042] Obviously, the fuel chemical chain hydrogen production system of the present invention can not only produce pure hydrogen with high efficiency and on a large scale, but is also very suitable for fuel-H2-PEMFC distributed fuel cell combined heat and power or cooling, heating and power trigeneration systems.

[0043] This is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of Example 1 of the fuel chemical chain hydrogen production system of the present invention.

[0045] Figure 2 Schematic diagram of Example 2 of the fuel chemical chain hydrogen production system of the present invention.

[0046] Figure 3 Schematic diagram of Example 3 of the fuel chemical chain hydrogen production system of the present invention.

[0047] Figure 4 Schematic diagram of Example 4 of the fuel chemical chain hydrogen production system of the present invention.

[0048] Figure 5 Schematic diagram of Example 5 of the fuel chemical chain hydrogen production system of the present invention.

[0049] Figure 6 It is a schematic diagram of Example 6 of the fuel chemical chain hydrogen production system of the present invention. DETAILED DESCRIPTION

[0050] To further illustrate the technical means and effectiveness of the present invention in achieving its intended objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail a fuel chemical chaining hydrogen production system and method according to the present invention, including its specific implementation, structure, features, and effectiveness. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0051] Example 1

[0052] This embodiment provides a fuel chemical chain hydrogen production system, such as Figure 1 shown.

[0053] The fuel chemical looping hydrogen production system provided in this embodiment includes two identical chemical looping combustion reactors, namely a first chemical looping combustion reactor 10 and a second chemical looping combustion reactor 20, wherein both chemical looping combustion reactors include an outer tube 11 and an inner tube 12 arranged coaxially with the outer tube, the inner tube is filled with a first oxygen carrier 13, and the interlayer between the outer tube and the inner tube is filled with a second oxygen carrier 14; the upper end of the inner tube is connected to a water vapor introduction pipe 41 and a fuel introduction pipe 42, and the lower end of the inner tube is connected to a gas outlet pipe, and the gas outlet pipe passes through a third The three-way valve 53 (or the fourth three-way valve 54) is connected to the hydrogen outlet pipe 43 and the reduction reaction product gas connecting pipe 44, and the other end of the reduction reaction product gas connecting pipe 44 is connected to the lower end of the interlayer; the upper end of the interlayer is connected to the combustion flue gas outlet pipe 46, and the lower end of the interlayer is connected to the combustion air inlet pipe 45; the water vapor inlet pipes 41 of the two chemical chain combustion reactors are connected through the first three-way valve 51, the fuel inlet pipe 42 is connected through the second three-way valve 52, and the combustion air inlet pipe 45 is connected through the fifth three-way valve 55.

[0054] This embodiment provides a fuel chemical chain hydrogen production system that can efficiently produce pure hydrogen from various fuels. It has a simple process, a simple and compact reactor structure, is easy to miniaturize, and has high hydrogen production efficiency. It is very suitable for fuel-H2-PEMFC distributed cogeneration systems.

[0055] Furthermore, the fuel is a gaseous or liquid fuel; the first oxygen carrier is an oxygen carrier with iron oxide as the main active ingredient; the second oxygen carrier is an iron-based oxygen carrier, a copper-based oxygen carrier, a nickel-based oxygen carrier, a calcium-based oxygen carrier, a manganese-based oxygen carrier, or a mixture of two or more thereof.

[0056] Example 2

[0057] This embodiment provides a fuel chemical chain hydrogen production system, such as Figure 2 shown.

[0058] In the fuel chemical looping hydrogen production system provided in this embodiment, water vapor is added to the fuel, and a steam reforming catalyst 15 is also filled above the first oxygen carrier filling layer to perform the steam reforming reaction of the fuel and the CO water gas shift reaction. Preferably, the steam reforming catalyst can be a Ni-based reforming catalyst or a Ru-based reforming catalyst.

[0059] In the fuel chemical chain hydrogen production system provided in this embodiment, a steam reforming catalyst is filled above the first oxygen carrier filling layer, so that before the fuel reacts with Fe3O4, the fuel is pre-converted into CO and H2 with stronger reducing ability through the steam reforming reaction, thereby significantly reducing the temperature required for Fe3O4 to be reduced to FeO, significantly widening the reduction reaction temperature window, avoiding the sintering of the oxygen carrier, and extending the service life of the oxygen carrier. Furthermore, CO and H2 can further reduce a portion of the FeO to Fe, thereby increasing the ability of the first oxygen carrier to generate H2. In addition, the steam reforming reaction of the fuel is a highly endothermic reaction. By filling the upper part of the inner tube with a steam reforming catalyst, the reaction gas of the steam reforming reaction forms a countercurrent heat exchange with the combustion flue gas, significantly reducing the outlet temperature of the combustion flue gas, thereby further improving the hydrogen production efficiency.

[0060] Furthermore, in the fuel chemical chaining hydrogen production system provided in this embodiment, a desulfurizer 16 is also filled above the filling layer of the steam reforming catalyst to perform a desulfurization reaction on the fuel. Preferably, the desulfurizer can be iron oxide or copper oxide desulfurizer.

[0061] Usually, a small amount of sulfur-based odorants such as tetrahydrothiophene are added to natural gas. In this embodiment, iron oxide or copper oxide desulfurizers are used to deeply remove sulfides through chemical adsorption reaction at temperatures above 100°C, thereby avoiding sulfur poisoning and deactivation of the steam reforming catalyst.

[0062] Example 3

[0063] This embodiment provides a fuel chemical chain hydrogen production system, such as Figure 3 shown.

[0064] In the fuel chemical chain hydrogen production system provided in this embodiment, a methanation reactor 30 is further provided on the hydrogen outlet pipe, and the methanation reactor is filled with a methanation catalyst 31.

[0065] In this embodiment, a methanation reactor is provided on the hydrogen outlet pipe to convert a small amount of CO2 and CO mixed into the hydrogen during switching into CH4 which is harmless to the H2-PEMFC stack.

[0066] Example 4

[0067] This embodiment provides a fuel chemical chain hydrogen production system, such as Figure 4 shown.

[0068] In the fuel chemical loop hydrogen production system provided in this embodiment, a flue gas heat exchanger 64 for flue gas and water is further provided on the flue gas duct 46, and the generated water vapor is used as the water vapor required for hydrogen production by the fuel chemical loop hydrogen production system.

[0069] Furthermore, in the fuel chemical looping hydrogen production system provided in this embodiment, a first hydrogen-water heat exchanger 60 is provided on the hydrogen pipeline 43. The generated water vapor is used as the water vapor required for hydrogen production in the fuel chemical looping hydrogen production system. Furthermore, the temperature of the methanation reaction is optimized by controlling the flow rate of water introduced into the first hydrogen heat exchanger 60.

[0070] Furthermore, in the fuel chemical chain hydrogen production system provided in this embodiment, a second hydrogen and water heat exchanger 62 is provided on the hydrogen pipeline at the outlet of the methanation reactor, and the generated water vapor is used as the water vapor required for hydrogen production by the fuel chemical chain hydrogen production system.

[0071] The fuel chemical chaining hydrogen production system provided in this embodiment includes a flue gas heat exchanger and a hydrogen heat exchanger, which utilizes the waste heat of flue gas and hydrogen to produce water vapor required by the fuel chemical chaining hydrogen production system, thereby further improving the hydrogen production efficiency.

[0072] Example 5

[0073] This embodiment provides a fuel chemical chain hydrogen production system, such as Figure 5 shown.

[0074] The fuel chemical chain hydrogen production system provided in this embodiment also includes a second type of absorption heat pump subsystem, which includes a generator 70, a condenser 130, a first evaporator 80, a first absorber 90 and a solution heat exchanger 100, wherein the generator 70 includes a solution spraying device 71 and a generating heat exchanger; the condenser 130 includes a condensing heat exchanger 132, the inlet of the condensing heat exchanger 132 is connected to the first water inlet pipe 133, and the outlet of the condensing heat exchanger 132 is connected to the first water vapor outlet pipe 134; the generator 70 and the condenser 130 are connected through the working medium vapor channel 134; the first evaporator 80 includes a working medium spraying device 81 and an evaporating heat exchanger; the first absorber 90 includes a solution The spray device 91 and the first absorption heat exchanger 92, the inlet of the first absorption heat exchanger 92 is connected to the second water inlet pipe 93, and the outlet of the first absorption heat exchanger 92 is connected to the second water vapor outlet pipe 94; the first evaporator 80 and the first absorber 90 are connected through the working medium vapor channel 84; the generator 70 is connected to the first absorber 90 through the first solution circulation pipe 103 and the second solution circulation pipe 104, the first solution circulation pipe 103 is provided with a solution circulation pump 74 and a solution heat exchanger 100, and the second solution circulation pipe 104 is provided with a solution heat exchanger 100 and a throttle valve 101; the condensed working medium is transported from the condenser 130 to the first evaporator 80 through the condensed working medium pump 136 and the condensed working medium pipe 135.

[0075] Furthermore, the generating heat exchanger includes a first generating heat exchanger 72 and a second generating heat exchanger 73; the evaporating heat exchanger includes a first evaporating heat exchanger 82 and a second evaporating heat exchanger 83; the inlet of the first generating heat exchanger 72 is connected to the flue gas outlet pipe 46, the outlet of the first generating heat exchanger is connected to the inlet of the first evaporating heat exchanger 82, the inlet of the second generating heat exchanger 73 is connected to the hydrogen outlet pipe 43, the outlet of the second generating heat exchanger 73 is connected to the inlet of the methanation reactor 30, and the outlet of the methanation reactor 30 is connected to the inlet of the second evaporating heat exchanger 83. In the generator 70, the dilute absorption solution from the first absorber 90 absorbs the high-temperature part of the flue gas waste heat and the high-temperature part of the hydrogen waste heat through the first generation heat exchanger 72 and the second generation heat exchanger 73 respectively to generate working fluid vapor, and at the same time, the dilute absorption solution is concentrated into a concentrated absorption solution, and the working fluid vapor enters the condenser 130 through the working fluid vapor channel 84, and the concentrated absorption solution enters the first absorber 90 through the first solution circulation pipe 103, the solution circulation pump 74 and the solution heat exchanger 100; in the condenser 130, the water passing through the first water inlet pipe 133 absorbs the condensation heat of the working fluid vapor through the condensation heat exchanger 132 and evaporates into water vapor with a pressure higher than 0.1 MPa and a temperature higher than 100°C, and at the same time, the working fluid vapor is condensed into a condensed working fluid, and the condensed working fluid is condensed through the condensation working fluid pump 136 and the condensation working fluid pump 137. The medium pipe 135 enters the first evaporator 80; in the first evaporator 80, the condensed working medium from the condenser 130 absorbs the low-temperature part of the flue gas waste heat and the low-temperature part of the hydrogen waste heat respectively to generate working medium vapor, and the working medium vapor enters the first absorber 90 through the working medium vapor channel 84; in the first absorber 90, the concentrated absorption solution from the generator 70 absorbs the working medium vapor from the first evaporator 80 and releases absorption heat with an increased temperature grade. At the same time, the concentrated absorption solution is diluted into a dilute absorption solution, and the water passing through the second water inlet pipe 93 absorbs the absorption heat through the first absorption heat exchanger 92 and evaporates into water vapor with a pressure higher than 0.1 MPa and a temperature higher than 100°C. The dilute absorption solution enters the generator 70 through the second solution circulation pipe 104, the solution heat exchanger 100 and the throttle valve 101. In this embodiment, the high-temperature portion of the flue gas waste heat and the high-temperature portion of the hydrogen waste heat are used as the driving heat source of the second-type absorption heat pump subsystem generator 70, the low-temperature portion of the flue gas waste heat and the low-temperature portion of the hydrogen waste heat are used as the low-temperature heat source of the second-type absorption heat pump subsystem evaporator 80, and the water vapor generated by the condensing heat exchanger 132 and the first absorption heat exchanger 92 is used as the water vapor required for hydrogen production in the fuel chemical chain hydrogen production system, thereby further improving the hydrogen production efficiency of the system.

[0076] Example 6

[0077] This embodiment provides a fuel chemical chain hydrogen production system, such as Figure 6 shown.

[0078] The fuel chemical chain hydrogen production system provided in this embodiment also includes a first type absorption heat pump subsystem or an absorption refrigeration subsystem, which includes a generator 70, a condenser 130, a second evaporator 110, a second absorber 120 and a solution heat exchanger 100, wherein the generator 70 includes a solution spraying device 71 and a generating heat exchanger; the condenser 130 includes a condensing heat exchanger 132, the inlet of the condensing heat exchanger 132 is connected to the first water inlet pipe 133, and the outlet of the condensing heat exchanger 132 is connected to the first water vapor outlet pipe 134; the generator 70 and the condenser 130 are connected through the working medium vapor channel 134; the second evaporator 110 is connected to the second absorber 120, and the second absorber 120 is connected to the first water vapor outlet pipe 134; the generator 70 and the condenser 130 are connected through the working medium vapor channel 134; the second evaporator 110 is connected to the second absorber 120, and the second absorber 120 is connected to the second ... absorber 120; the generator 70 includes a solution spraying device 71 and a generating heat exchanger; the condenser 130 includes a condensing heat exchanger 132, the inlet of the condensing heat exchanger 132 is connected to the first water inlet pipe 133, and the outlet of the condensing heat exchanger 132 is connected to the first water vapor outlet pipe 134; the generator 70 and the condenser 130 are connected through the 10 includes a working fluid spray device 111 and a third evaporation heat exchanger 112; the second absorber 120 includes a solution spray device 121 and a second absorption heat exchanger 122; the second evaporator 110 and the second absorber 120 are connected through a working fluid vapor channel 114; the generator 70 is connected to the second absorber 120 through a third solution circulation pipeline 105 and a fourth solution circulation pipeline 106, the fourth solution circulation pipeline 106 is provided with a solution circulation pump 74 and a solution heat exchanger 100, and the third solution circulation pipeline 105 is provided with a solution heat exchanger 100 and a throttle valve 101; the condensed working fluid is transported from the condenser 130 to the second evaporator 110 through the condensed working fluid pipeline 107 and the throttle valve 102.

[0079] Furthermore, the heat exchanger includes a first heat exchanger 72 and a second heat exchanger 73; the inlet of the first heat exchanger 72 is connected to the flue gas outlet pipe 46, the outlet of the first heat exchanger 72 is connected to the inlet of the flue gas heat exchanger 64, the inlet of the second heat exchanger 73 is connected to the hydrogen outlet pipe 43, the outlet of the second heat exchanger 73 is connected to the inlet of the methanation reactor 30, and the outlet of the methanation reactor 30 is connected to the inlet of the second hydrogen heat exchanger 62. The inlet and outlet of the third evaporative heat exchanger 112 are respectively connected to the inlet pipe 117 and outlet pipe 118 of the refrigerant fluid; alternatively, the inlet and outlet of the third evaporative heat exchanger 112 are respectively connected to the inlet pipe 117 and outlet pipe 118 of the low-temperature heat source fluid, and the inlet and outlet of the second absorption heat exchanger 122 are respectively connected to the inlet pipe 123 and outlet pipe 124 of the heat medium fluid. In the generator 70, the dilute absorption solution from the second absorber 120 absorbs the high-temperature part of the flue gas waste heat and the high-temperature part of the hydrogen waste heat through the first generation heat exchanger 72 and the second generation heat exchanger 73 respectively to generate working fluid vapor, and at the same time, the dilute absorption solution is concentrated into a concentrated absorption solution, and the working fluid vapor enters the condenser 130 through the working fluid vapor channel 84, and the concentrated absorption solution enters the second absorber 120 through the third solution circulation pipe 105, the solution heat exchanger 100 and the throttle valve 101; in the condenser 130, the water through the first water inlet pipe 133 absorbs the condensation heat of the working fluid vapor through the condensation heat exchanger 132 and evaporates into water vapor with a pressure higher than 0.1 MPa and a temperature higher than 100°C, and at the same time, the working fluid vapor is condensed into a condensed working fluid, and the condensed working fluid enters the second evaporator 110 through the condensation working fluid pipe 107 and the throttle valve 102; in the second evaporator 110, the condensed working fluid from the condenser 130 absorbs the working fluid vapor through the third evaporation heat exchanger 112 and evaporates into water vapor with a pressure higher than 0.1 MPa and a temperature higher than 100°C. The heat of the refrigerant fluid in the inlet pipe 117 of the refrigerant fluid is used to generate working fluid vapor, and external cooling is achieved through the outlet pipe 118 of the refrigerant fluid. The working fluid vapor enters the second absorber 120 through the working fluid vapor channel 114, or the condensed working fluid from the condenser 130 absorbs the heat of the low-temperature heat source fluid through the inlet pipe 117 of the low-temperature heat source fluid through the third evaporative heat exchanger 112 to generate working fluid vapor; in the second absorber 120, the concentrated absorption solution from the generator 70 absorbs the working fluid vapor from the second evaporator 110 and releases absorption heat with an increased temperature grade. At the same time, the concentrated absorption solution is diluted into a dilute absorption solution, and the heat medium fluid through the inlet pipe 123 of the heat medium fluid absorbs the absorption heat through the second absorption heat exchanger 122, and external heating is achieved through the outlet pipe 124 of the heat medium fluid. The dilute absorption solution enters the generator 70 through the fourth solution circulation pipe 106, the solution circulation pump 74 and the solution heat exchanger 100.In this embodiment, the high-temperature portion of the flue gas waste heat and the high-temperature portion of the hydrogen waste heat are used as the driving heat source of the absorption refrigeration subsystem generator 70 for cooling; or the high-temperature portion of the flue gas waste heat and the high-temperature portion of the hydrogen waste heat are used as the driving heat source of the first-type absorption heat pump subsystem generator 70, and the low-grade thermal energy is used as the low-temperature heat source of the first-type absorption heat pump subsystem evaporator 110 for heating, and at the same time, the water vapor generated by the condensing heat exchanger 132, the flue gas heat exchanger 64, and the second hydrogen heat exchanger 62 is used as the water vapor required for hydrogen production in the fuel chemical chain hydrogen production system, thereby further improving the hydrogen production efficiency and comprehensive energy utilization efficiency of the system.

[0080] Example 7

[0081] This embodiment provides a method for producing hydrogen from fuel using a chemical chain.

[0082] When the first chemical looping combustion reactor of the two chemical looping combustion reactors introduces water vapor through the water vapor introduction pipe to carry out an oxidation reaction of the oxygen carrier with the reduced oxygen carrier to generate hydrogen, and the hydrogen is discharged through the hydrogen discharge pipe, the second chemical looping combustion reactor introduces fuel or a mixture of fuel and water vapor through the fuel or fuel and water vapor introduction pipe to carry out a reduction reaction of the oxygen carrier with the oxidized oxygen carrier to generate a reduction reaction product gas, the reduction reaction product gas is introduced into the interlayer through the reduction reaction product gas connecting pipe, and the combustion-supporting air is introduced into the interlayer through the combustion-supporting air introduction pipe to carry out a chemical looping combustion reaction of the reduction reaction product gas;

[0083] When the oxidation reaction of the reduced oxygen carrier in the first chemical looping combustion reactor is completed, by switching the 1st to 5th three-way valves, the first chemical looping combustion reactor performs the reduction reaction of the oxidized oxygen carrier and the chemical looping combustion reaction of the reduction reaction product gas, and the second chemical looping combustion reactor performs the oxidation reaction of the reduced oxygen carrier.

[0084] Taking CH4 as an example, the first oxygen carrier is an iron-based oxygen carrier Fe3O4 / Al2O3. The reaction equations for the oxygen carrier oxidation reaction between the reduced oxygen carrier and water vapor and the oxygen carrier reduction reaction between the oxidized oxygen carrier and the fuel, as well as the standard free energy change and reaction heat at 750°C are as follows:

[0085] Reduction reaction of oxidized oxygen carriers:

[0086] 4Fe3O4+CH4=12FeO+CO2+2H2O (1)

[0087] ΔG=-39.9kJ / mol; ΔH=367.9kJ / mol

[0088] The reduction reaction (1) of Fe3O4 / Al2O3 is a strongly endothermic reaction.

[0089] Oxidation reaction of reduced oxygen carriers:

[0090] 3FeO+H2O=Fe3O4+H2 (2)

[0091] ΔG=1.3kJ / mol; ΔH=-44.5kJ / mol

[0092] The reduction reaction (2) of FeO / Al2O3 is an exothermic reaction.

[0093] Taking the nickel-based oxygen carrier NiO / Al2O3 as an example, the chemical looping combustion reaction of the reduction reaction product gas (mainly CH4) and air includes the reduction reaction of the oxidized oxygen carrier NiO / Al2O3 and the oxidation regeneration reaction of the reduced oxygen carrier Ni / Al2O3. The reaction equation, standard free energy change at 900°C, and reaction heat are shown below:

[0094] Reduction reaction of oxidized oxygen carriers:

[0095] 4NiO+CH4=4Ni+CO2+2H2O (3)

[0096] ΔG=-265.9kJ / mol; ΔH=136.2kJ / mol

[0097] Oxidation reaction of reduced oxygen carriers:

[0098] 4Ni+2O2=4NiO (4)

[0099] ΔG=-534.0kJ / mol; ΔH=-938.4kJ / mol

[0100] The overall chemical looping combustion reaction of the reduction reaction product gas is:

[0101] CH4+2O2=CO2+2H2O (5)

[0102] ΔG=-799.9kJ / mol; ΔH=-802.2kJ / mol

[0103] The chemical chain combustion reaction (5) of the reduction reaction product gas is a highly exothermic reaction.

[0104] Taking the steam reforming reaction using a Ni / Al2O3 reforming catalyst and a water-to-carbon ratio of 1.5 as an example, the reaction equations for the steam reforming reaction of CH4 and the CO water-gas shift reaction, as well as the standard free energy change and reaction heat at 750°C, are shown below:

[0105] Steam reforming reaction:

[0106] CH4+H2O=3H2+CO (6)

[0107] ΔG=-32.6kJ / mol; ΔH=224.7kJ / mol

[0108] The steam reforming reaction (6) of CH4 is a highly endothermic reaction.

[0109] CO water gas shift reaction:

[0110] CO+H2O=H2+CO2 (7)

[0111] ΔG=-2.1kJ / mol; ΔH=-34.6kJ / mol

[0112] The CO water gas shift reaction (7) is an exothermic reaction.

[0113] Taking Ni / Al2O3 methanation catalyst as an example, the reaction equation for the methanation reaction of a small amount of CO and CO2, as well as the standard free energy change and reaction heat at 250°C are shown below:

[0114] CO+3H2=CH4+H2O (8)

[0115] ΔG=-90.7kJ / mol; ΔH=-214.8kJ / mol

[0116] CO2+4H2=CH4+2H2O (9)

[0117] ΔG=-71.2kJ / mol; ΔH=-175.1kJ / mol

[0118] Furthermore, when the oxidation reaction of the reduced oxygen carrier in the first chemical looping combustion reactor is completed, the first and second three-way valves are first switched, causing the first chemical looping combustion reactor to begin the reduction reaction of the oxidized oxygen carrier and the chemical looping combustion reaction of the reduction reaction product gas. The second chemical looping combustion reactor then begins the oxidation reaction of the reduced oxygen carrier. After a time t has elapsed, the third to fifth three-way valves are switched. The time t is more preferably 5 to 30 seconds.

[0119] When switching between two chemical looping combustion reactors, first switch the first and second three-way valves, and then switch the third through fifth three-way valves 5 to 30 seconds later. This increases hydrogen production efficiency while also reducing the amount of impurities such as CO2 and CO mixed into the hydrogen.

[0120] Furthermore, the oxidation reaction temperature of the reduced oxygen carrier is 700-850°C; the reduction reaction temperature of the oxidized oxygen carrier is 700-850°C; and the combustion reaction temperature of the reduction reaction product gas is 850-1000°C. The steam reforming reaction temperature is 450-750°C, with a water-to-carbon ratio of 0.5-2.0; the desulfurization reaction temperature is 100-450°C; and the methanation reaction temperature is 150-400°C.

[0121] Furthermore, although the FeO / Al2O3 oxidation reaction (2) and the CO water vapor shift reaction (7) are exothermic reactions, their heat release is significantly lower than the heat absorption of the Fe3O4 / Al2O3 reduction reaction (1) and the CH4 steam reforming reaction (6). The shortfall is covered by the chemical looping combustion heat of the reduction reaction product gas. Under the condition of producing a certain amount of hydrogen, in addition to changing the CH4 flow rate, the present invention also optimizes the CH4 conversion rate by controlling the steam reforming reaction temperature and water-to-carbon ratio, so that the heat matching and temperature distribution of the chemical looping combustion reactor are met, thereby improving the fuel production efficiency.

[0122] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0123] It is understood that the related features in the above devices can be referenced to each other. In addition, the "first", "second", etc. in the above embodiments are used to distinguish between the embodiments, and do not represent the advantages and disadvantages of the embodiments.

[0124] The numerical range described in the present invention includes all values ​​within this range, and includes the range value formed by any two values ​​within this range.

[0125] The technical features in the claims and / or the specification of the present invention may be combined, and the manner of combination is not limited to the combination obtained by reference in the claims. The technical solutions obtained by combining the technical features in the claims and / or the specification are also within the scope of protection of the present invention.

[0126] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A fuel chemical chain hydrogen production system, characterized in that: It consists of two identical chemical looping combustion reactors, in which The chemical looping combustion reactor comprises an outer tube and an inner tube coaxially arranged with the outer tube, the inner tube is filled with a first oxygen carrier, and the interlayer between the outer tube and the inner tube is filled with a second oxygen carrier; the second oxygen carrier is an iron-based oxygen carrier, a copper-based oxygen carrier, a nickel-based oxygen carrier, a calcium-based oxygen carrier, a manganese-based oxygen carrier, or a mixture of two or more thereof; The upper end of the inner tube is connected to a water vapor inlet pipe and a fuel inlet pipe, and the lower end of the inner tube is connected to a gas outlet pipe. The gas outlet pipe is connected to the hydrogen outlet pipe and the reduction reaction product gas communication pipe through a third three-way valve. The other end of the reduction reaction product gas communication pipe is connected to the lower end of the interlayer; The upper end of the interlayer is connected to a combustion flue gas outlet pipe, and the lower end of the interlayer is connected to a combustion air inlet pipe; The water vapor inlet pipes of the two chemical looping combustion reactors are connected through a first three-way valve, the fuel inlet pipes are connected through a second three-way valve, and the combustion air inlet pipes are connected through a fifth three-way valve.

2. The fuel chemical chain hydrogen production system according to claim 1, characterized in that: The fuel is gaseous or liquid fuel; The first oxygen carrier is an oxygen carrier with iron oxide as the main active component.

3. The fuel chemical chain hydrogen production system according to claim 1, characterized in that: Water vapor is added to the fuel, and a steam reforming catalyst is filled above the first oxygen carrier filling layer to perform a steam reforming reaction of the fuel and a CO water vapor shift reaction; The upper portion of the filling layer of the steam reforming catalyst is filled with a desulfurizing agent to carry out a desulfurization reaction of the fuel.

4. The fuel chemical chain hydrogen production system according to any one of claims 1 to 3, characterized in that: A methanation reactor is provided on the hydrogen outlet pipeline, and the methanation reactor is filled with a methanation catalyst.

5. The fuel chemical chain hydrogen production system according to any one of claims 1 to 3, characterized in that: A flue gas heat exchanger between flue gas and water is also provided on the flue gas pipeline, and the water vapor generated is used as the water vapor required for hydrogen production by the fuel chemical chain hydrogen production system.

6. The fuel chemical chain hydrogen production system according to any one of claims 1 to 3, characterized in that: A first hydrogen heat exchanger between hydrogen and water is also provided on the hydrogen pipeline, and the generated water vapor is used as the water vapor required for hydrogen production by the fuel chemical chain hydrogen production system.

7. The fuel chemical chain hydrogen production system according to claim 4, characterized in that: A second hydrogen heat exchanger for hydrogen and water is also provided on the hydrogen pipeline at the outlet of the methanation reactor, and the generated water vapor is used as the water vapor required for hydrogen production by the fuel chemical chain hydrogen production system.

8. The fuel chemical chain hydrogen production system according to claim 4, characterized in that: It also includes a second type of absorption heat pump subsystem, which includes a generator, a condenser, a first evaporator, a first absorber and a solution heat exchanger, wherein the generator includes a solution spraying device and a generator heat exchanger; the condenser includes a condensing heat exchanger, the inlet of the condensing heat exchanger is connected to the first water inlet pipe, and the outlet of the condensing heat exchanger is connected to the first water vapor outlet pipe; the first evaporator includes a working fluid spraying device and an evaporation heat exchanger; the first absorber includes a solution spraying device and a first absorption heat exchanger, the inlet of the first absorption heat exchanger is connected to the second water inlet pipe, and the outlet of the first absorption heat exchanger is connected to the second water vapor outlet pipe; the water vapor generated by the condensing heat exchanger and the first absorption heat exchanger is used as the water vapor required for hydrogen production by the fuel chemical chain hydrogen production system.

9. The fuel chemical chain hydrogen production system according to claim 8, characterized in that: The generating heat exchanger includes a first generating heat exchanger and a second generating heat exchanger; the evaporating heat exchanger includes a first evaporating heat exchanger and a second evaporating heat exchanger; the inlet of the first generating heat exchanger is connected to the flue gas outlet pipe, the outlet of the first generating heat exchanger is connected to the inlet of the first evaporating heat exchanger, the inlet of the second generating heat exchanger is connected to the hydrogen outlet pipe, the outlet of the second generating heat exchanger is connected to the inlet of the methanation reactor, and the outlet of the methanation reactor is connected to the inlet of the second evaporating heat exchanger.

10. The fuel chemical chain hydrogen production system according to claim 4, characterized in that: It also includes a first type of absorption heat pump subsystem or absorption refrigeration subsystem, which includes a generator, a condenser, a second evaporator, a second absorber and a solution heat exchanger, and the generator includes a solution spraying device and a generator heat exchanger; the condenser includes a condensing heat exchanger, the inlet of the condensing heat exchanger is connected to the first water inlet pipe, and the outlet of the condensing heat exchanger is connected to the first water vapor outlet pipe; the second evaporator includes a working fluid spraying device and a third evaporation heat exchanger; the second absorber includes a solution spraying device and a second absorption heat exchanger; the water vapor generated by the condensing heat exchanger is used as the water vapor required for hydrogen production in the fuel chemical chain hydrogen production system.

11. The fuel chemical chain hydrogen production system according to claim 10, characterized in that: The heat exchanger includes a first heat exchanger and a second heat exchanger; the inlet of the first heat exchanger is connected to the flue gas outlet pipe, the inlet of the second heat exchanger is connected to the hydrogen outlet pipe, and the outlet of the second heat exchanger is connected to the inlet of the methanation reactor.

12. A method for producing hydrogen by fuel chemical chaining, characterized in that: The fuel chemical chain hydrogen production system according to any one of claims 1 to 7 is used, and the hydrogen production method includes: When the first chemical looping combustion reactor of the two chemical looping combustion reactors introduces water vapor through the water vapor introduction pipe to carry out an oxidation reaction of the oxygen carrier with the reduced oxygen carrier to generate hydrogen, and the hydrogen is discharged through the hydrogen discharge pipe, the second chemical looping combustion reactor introduces fuel or a mixture of fuel and water vapor through the fuel or fuel and water vapor introduction pipe to carry out a reduction reaction of the oxygen carrier with the oxidized oxygen carrier to generate a reduction reaction product gas, the reduction reaction product gas is introduced into the interlayer through the reduction reaction product gas connecting pipe, and the combustion-supporting air is introduced into the interlayer through the combustion-supporting air introduction pipe to carry out a chemical looping combustion reaction of the reduction reaction product gas; When the oxidation reaction of the reduced oxygen carrier in the first chemical looping combustion reactor is completed, by switching the 1st to 5th three-way valves, the first chemical looping combustion reactor performs the reduction reaction of the oxidized oxygen carrier and the chemical looping combustion reaction of the reduction reaction product gas, and the second chemical looping combustion reactor performs the oxidation reaction of the reduced oxygen carrier.

13. The method for producing hydrogen from fuel chemical chain according to claim 12, characterized in that: When the oxidation reaction of the reduced oxygen carrier in the first chemical looping combustion reactor is completed, first switch the 1st and 2nd three-way valves, so that the first chemical looping combustion reactor starts the reduction reaction of the oxidized oxygen carrier and the chemical looping combustion reaction of the reduction reaction product gas, and the second chemical looping combustion reactor starts the oxidation reaction of the reduced oxygen carrier. After time t, switch the 3rd to 5th three-way valves.

14. The method for producing hydrogen from fuel chemical chain according to claim 13, characterized in that: The time t is 5 to 30 seconds.

15. The method for producing hydrogen from fuel chemical chain according to claim 12, characterized in that: The oxidation reaction temperature of the reduced oxygen carrier is 700-850°C; the reduction reaction temperature of the oxidized oxygen carrier is 700-850°C; and the combustion reaction temperature of the reduction reaction product gas is 850-1000°C.

16. The method for producing hydrogen from fuel chemical chain according to claim 12, characterized in that: The steam reforming reaction temperature is 450-750°C, and the water-to-carbon ratio is 0.5-2.0; or, The desulfurization reaction temperature is 100-450°C; the methanation reaction temperature is 150-400°C.

17. A method for producing hydrogen by fuel chemical chaining, characterized in that: A fuel chemical chain hydrogen production system according to any one of claims 8 to 9 is adopted, wherein the high-temperature portion of the flue gas waste heat and the high-temperature portion of the hydrogen waste heat are used as driving heat sources for the generator of the second-type absorption heat pump subsystem, and the low-temperature portion of the flue gas waste heat and the low-temperature portion of the hydrogen waste heat are used as low-temperature heat sources for the evaporator of the second-type absorption heat pump subsystem.

18. A method for producing hydrogen by chemical chaining of fuel, characterized in that: The fuel chemical chain hydrogen production system according to any one of claims 10-11 is adopted, and the high-temperature portion of the flue gas waste heat and the high-temperature portion of the hydrogen waste heat are used as the driving heat source of the first-type absorption heat pump subsystem or the absorption refrigeration subsystem generator to provide heating or cooling or combined heat and cold.

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