A distributed clean hydrogen and power cogeneration device

Abstract

The present invention relates to a distributed clean hydrogen cogeneration device, which includes a skid-mounted hydrogen production and power generation device and a hydrogen refueling charging station. The fuel is a methane-rich raw material. The skid-mounted hydrogen production and power generation device includes three systems in series, namely a chemical chain hydrogen cogeneration system, a fuel cell and a supercritical carbon dioxide Brayton cycle. The hydrogen refueling charging station is equipped with a hydrogen storage device and a main power supply. The device can supply power and produce hydrogen simultaneously, realize hydrogen and electricity complementarity, and flexibly switch between different modes of operation according to the back-end hydrogen and electricity supply needs. The device captures all the carbon dioxide produced by the reaction, recycles all the water, and realizes the cascade utilization of high and low-grade energy. Compared with the existing technology, the system of the present invention has high energy efficiency, strong cleanliness, flexible matching of power grid demand, and can adjust the hydrogen and electricity supply ratio on demand.

Description

Technical Field

[0001] The invention relates to a distributed clean hydrogen and electricity cogeneration device, belonging to the technical field of energy chemical industry. Background Art

[0002] Both hydrogen and electricity play crucial roles in the energy sector. With the advancement of society, hydrogen energy is gaining increasing attention. Existing hydrogen production plants and power plants are independent systems. The former primarily produces hydrogen from hydrogen-containing substances through chemical reactions, electrolysis, and thermal decomposition, while the latter primarily converts heat generated by fuel combustion, nuclear fission, and solar radiation into electricity through thermodynamic cycles. In recent years, research on hydrogen-electricity cogeneration systems, including those based on fossil fuels and nuclear energy, has garnered widespread attention. These systems offer improved overall benefits.

[0003] Most existing hydrogen-power cogeneration systems focus on maximizing energy efficiency and are unable to adjust product ratios based on demand. Examples include a shale oil distillation gas chemical chain hydrogen production combined power generation system and a coal-fired boiler hydrogen-power cogeneration system and method. Typically, a charging and hydrogen refueling station primarily consists of hydrogen compression equipment, hydrogen storage tanks, hydrogen distribution devices, and power grid layout. The high cost of hydrogen compression equipment contributes to the high cost of configuring a complete hydrogen refueling station, significantly impacting the economic benefits of the station when hydrogen demand is low.

[0004] Chemical-linking hydrogen-power cogeneration is one of the most promising hydrogen production technologies for industrialization. It combines hydrogen production with power generation and CO2 capture. It splits the reaction into three steps, producing hydrogen and CO2 in two separate reactors without the need for gas separation. This approach offers high hydrogen production efficiency, high hydrogen purity, and near-zero CO2 emissions, making it ideally suited to current and future hydrogen production technology development requirements. Summary of the Invention

[0005] The present invention aims to solve the problem of how to produce hydrogen and generate electricity more cleanly and efficiently, and flexibly handle the supply and demand of hydrogen and electricity.

[0006] The technical problem to be solved by this invention is to overcome the shortcomings of existing technologies and provide an operating mode for a device that flexibly regulates hydrogen and electricity production. The device combines chemical chaining hydrogen and electricity generation with fuel cell power generation, adding a supercritical carbon dioxide Brayton cycle to generate electricity using waste heat from flue gas, achieving cascaded energy utilization and improving system energy efficiency. This invention can rationally select the appropriate operating mode based on hydrogen and electricity demand within a charging and hydrogen refueling station, flexibly matching grid demand.

[0007] The chemical chaining hydrogen-electricity cogeneration system includes an air reactor, a fuel reactor, a steam reactor, a waste heat boiler, a compressor, and a turbine. The first inlet of the air reactor receives compressed air, while the second inlet of the air reactor is connected to the second outlet of the steam reactor. The first outlet of the air reactor is connected to the second inlet of the fuel reactor. The fuel, after passing through the compressor, is connected to the first inlet of the fuel reactor. The second outlets of the air and fuel reactors generate electricity through the turbine, then recover high-quality heat energy through the waste heat boiler. The heat is then connected to the second inlet of the supercritical carbon dioxide Brayton cycle waste heat recovery unit described below. External water is pressurized by a pump and enters the waste heat boiler for heat exchange, before being connected to the second inlet of the steam reactor. The first outlet of the steam reactor is hydrogen, which, after generating electricity through the turbine, is connected to the fuel cell module.

[0008] The oxygen carrier selected in the present invention is iron oxide. The process of hydrogen production from hydrocarbon compounds under the action of the oxygen carrier mainly consists of three reactions: reduction reaction of the metal oxygen carrier, oxidation reaction, and combustion reaction. Taking methane as an example, the chemical chain hydrogen production process with iron oxide as the oxygen carrier is expressed as follows:

[0009] Fuel reactor reduction reaction:

[0010] CH4+Fe2O3→CO2+H2O+Fe / FeO (1)

[0011] Steam Reactor Oxidation Reaction:

[0012] Fe / FeO+H2O→Fe3O4+H2 (2)

[0013] Air reactor combustion reaction:

[0014] Fe3O4+O2→Fe2O3+Q(thermal energy) (3)

[0015] Overall reaction:

[0016] CH4+O2→CO2+H2+Q(heat energy) (4)

[0017] The supercritical CO2 Brayton cycle includes a CO2 main compressor, a recompressor, a turbine, a waste heat recovery unit, a high-temperature regenerator, and a low-temperature regenerator. The supercritical CO2 is connected to the turbine inlet, the turbine outlet to the high-temperature regenerator side inlet, the high-temperature regenerator side outlet to the low-temperature regenerator side inlet, the low-temperature regenerator side outlet to the splitter inlet, one splitter outlet branch to the cooler inlet, the cooler outlet to the main compressor inlet, and the main compressor outlet to the low-temperature regenerator for heat exchange; the other outlet branch is connected to the CO2 recompressor inlet, the low-temperature regenerator and recompressor outlets to the mixer inlet, and the mixer outlet to a high-temperature regenerator for heat exchange; finally, the CO2 at the high-temperature regenerator outlet passes through the waste heat recovery unit and enters the turbine, completing a power generation cycle.

[0018] Preferably, the flue gas from the air reactor, the fuel reactor and the steam reactor is passed through a turbine to generate electricity.

[0019] Preferably, the waste heat of the flue gas emitted from the air reactor, the fuel reactor and the fuel cell cathode is recovered and reused.

[0020] Preferably, the waste heat boiler can utilize the waste heat of the flue gas to heat the feed water, and the waste heat recovery device is used to heat the carbon dioxide working medium at the outlet of the high-temperature regenerator.

[0021] Preferably, the water vapor generated by the anode reaction of the fuel cell is recovered and used together with the pumped new water as the feed of the steam reactor.

[0022] Preferably, the raw natural gas and air preheating utilizes low-grade waste heat after heat exchange between the chemical chaining hydrogen and power cogeneration system and the fuel cell module to provide part or all of the heat.

[0023] Preferably, in the Mode 1 operation mode, all the electricity generated by the CLHG system is used for electrolysis of water.

[0024] Beneficial effects:

[0025] Compared with the existing technology, the beneficial effects and features of the present invention are as follows:

[0026] (1) The hydrogen production and power generation device can adjust the hydrogen-electricity supply ratio as needed and flexibly match the use of the power grid demand.

[0027] (2) The production of hydrogen using chemical looping combustion technology not only solves the raw material problem of fuel cell power generation, but also directly obtains electricity and separates carbon dioxide, achieving the purpose of carbon capture and near-zero emissions. It also solves the problem of reduced thermal efficiency of power plants due to carbon capture.

[0028] (3) Using chemical loop combustion technology to produce hydrogen as fuel for fuel cell power generation can solve the problem of anode carbon deposition in existing natural gas reforming hydrogen production coupled fuel cells.

[0029] (4) The heat energy generated by the chemical chain hydrogen and power cogeneration and fuel cells is used to heat the carbon dioxide working fluid, realizing the waste heat utilization of the system, reflecting the integrity of the system, and improving the efficiency and economy of the system.

[0030] (5) The hydrogen and electricity produced by the system are both ideal green energy carriers and can be directly used for production and daily life.

[0031] (6) The system’s hydrogen and electricity production levels are well matched, and both power generation and hydrogen production have the conditions for large-scale development. Miniaturization can also be designed to meet distributed applications.

[0032] (7) The system does not emit pollutants, captures 100% of the carbon dioxide generated by hydrogen production and power generation, and recycles 100% of the condensed water. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a specific implementation case of the present invention.

[0034] Figure 2 This is a system flow chart of a distributed clean hydrogen and power cogeneration device provided by the present invention. DETAILED DESCRIPTION

[0035] To further illustrate the purpose, technical solutions and beneficial effects of the present invention, Figure 1 、 Figure 2 The technical solution of the present invention is further described, but the present invention is not limited thereto.

[0036] It should be noted that when a component is referred to as being “fixed to” or “disposed on” another component, it may be directly on the other component or indirectly on the other component. When a component is referred to as being “connected to” another component, it may be directly connected to the other component or indirectly connected to the other component.

[0037] It should also be noted that the same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", etc. indicating an orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are for illustrative purposes only and cannot be understood as limiting this patent. For those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0038] In the present invention, the methane-rich fuel can be selected from methane-rich resources such as biogas, natural gas, shale gas, coalbed methane, refinery gas, coke oven gas, oilfield gas, and coal mine gas, or other high-carbon fuels suitable for CLHG systems. Preferably, the feed gas should undergo desulfurization, dechlorination, dearsenicization, and deweighting treatments before entering the chemical looping reactor. Typically, requirements include sulfur content <50 ppb, Cl <0.5 ppm, As <20 ppb, Hg <0.5 ppb, and a methane content >95% (volume percentage).

[0039] The chemical looping technology adopted in the present invention adopts a fixed bed reactor and simulates a moving bed equipment by switching the feeding mode through program control to produce electricity and high-purity hydrogen while outputting heat energy.

[0040] The near-zero emission and high-efficiency hydrogen production and power generation method provided by the present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited thereto.

[0041] Figure 1 This is a specific implementation case of the present invention. The present invention relates to a distributed clean hydrogen and electricity cogeneration device that can simultaneously realize power supply and hydrogen production. The specific implementation method of the device can switch between three operating modes through program control:

[0042] (1) During periods of high hydrogen demand, the device adopts the first operating mode for hydrogen production only: the shut-off valve (1) is closed, so that the hydrogen produced by the chemical chain hydrogen and power cogeneration system (CLHG) does not flow into the fuel cell module, but is directly sent to the hydrogen storage system for storage; the first solenoid valve (2) and the second solenoid valve (3) are closed, the fuel cell module and the s-CO2 cycle do not operate, and at the same time, the electricity generated by the chemical chain hydrogen and power cogeneration system (CLHG) flue gas after passing through the turbine is also fully used for hydrogen production by electrolysis of water; in this mode, the hydrogen supply can be met to the greatest extent;

[0043] (2) During periods of high electricity demand, the system uses the second power generation mode only for power generation: the shut-off valve (1), the first solenoid valve (2) and the second solenoid valve (3) are opened, so that the entire device operates efficiently according to the established mode; all hydrogen produced by the chemical chain hydrogen and power cogeneration system (CLHG) enters the fuel cell module as fuel, and the flue gas of the chemical chain hydrogen and power cogeneration system (CLHG) and the fuel cell is used to heat the carbon dioxide working medium of the s-CO2 cycle; in this mode, all three systems generate electricity, no hydrogen storage is performed, and the maximum demand for electricity is met;

[0044] (3) When the demand for hydrogen and electricity is between the above two, the device adopts the third power generation mode to flexibly control the hydrogen and electricity production: open the stop valve (1), the first solenoid valve (2) and the second solenoid valve (3) and open each ball valve (①~⑤) as needed, so that part of the hydrogen produced by the chemical chain hydrogen and electricity cogeneration system (CLHG) enters the fuel cell module, and the remaining hydrogen enters the hydrogen storage system for storage; in this mode, the device can allocate the amount of hydrogen and electricity produced according to the demand of the internal power grid to achieve the purpose of cogeneration of the device.

[0045] The skid-mounted hydrogen power generation system comprises three systems connected in series: a chemical-linking hydrogen-power cogeneration system, a fuel cell, and a supercritical carbon dioxide Brayton cycle. This system can simultaneously power and produce hydrogen, achieving a complementary hydrogen-electricity relationship. The ratio of hydrogen to electricity can be adjusted on demand, controlling the power generation of each module.

[0046] Example 1 (Energy source of hydrogen refueling station):

[0047] This device can serve as an energy source for hydrogen refueling stations. The station's main power supply can power each charging pile, and the resulting hydrogen is stored in a hydrogen storage device within the station. Therefore, the device has the dual function of providing both hydrogen and electricity, unrestricted by the external power grid. New energy vehicles can use the charging piles and hydrogen refueling nozzles within the station for both charging and refueling.

[0048] Example 2 (distributed clean hydrogen and power cogeneration device):

[0049] This skid-mounted, distributed, clean hydrogen and power cogeneration unit is also ideal for the company. The electricity generated is used to maintain operations, and the hydrogen produced can be used to refuel employees' new energy vehicles, eliminating the need to queue at refueling stations. The fuel feed rate can be adjusted at any time based on the required production capacity.

[0050] The present invention is a distributed clean hydrogen power device, the detailed working process is as follows Figure 2 shown.

[0051] Chemical-linking hydrogen-power cogeneration system: Compressor (1-2) pressurizes fuel (CH4) at 25°C and 1 bar to 10 bar. The fuel is then fed into the fuel reactor (1-4), where it reacts with Fe2O3 to form Fe / FeO at a temperature of 1000°C. The resulting gases are CO2 and water vapor. After generating electricity through a turbine (1-6), the gas enters a waste heat boiler (1-7), where the heat is further recovered and reused. The CO2 is easily separated by condensing the water vapor, enabling carbon capture and achieving near-zero emissions. The metal carrier (Fe / FeO) enters the steam reactor (1-8) and reacts with water vapor to generate H2 at a reaction temperature of 600°C. The Fe3O4 obtained from the steam reactor (1-8) and the air pressurized by the compressor (1-1) undergo a combustion reaction in the air reactor (1-3) to generate Fe2O3. The Fe2O3 then enters the fuel reactor (1-4) and undergoes a reduction reaction with the new fuel. The heat flow generated by the air reactor (1-3) is then introduced into the waste heat boiler (1-7) for recycling after passing through the turbine (1-5) to generate electricity.

[0052] Fuel cell power generation system: The present invention takes SOFC as an example, but is not limited to SOFC. Any fuel cell using hydrogen as raw material can be used. The hydrogen produced by the chemical chain is generated by the turbine (1-9) and then all / part of it is selected according to the power demand to enter the SOFC fuel cell (1-10) to provide it with fuel for the electrochemical reaction. The unreacted hydrogen and the generated water vapor are compressed to the operating pressure of the steam reactor (1-8) by the compressor (1-11) and then sent back into the cycle for full reaction. The inlet of the cathode of the SOFC fuel cell is preheated air, and after the cathode reaction, O 2- The oxygen-depleted flue gas flows to the anode and is discharged from the cathode outlet of the fuel cell. The heat energy contained in the flue gas will be reused below. The entire process realizes the power generation of the fuel cell based on the electrochemical reaction between the two electrodes.

[0053] Supercritical carbon dioxide Brayton cycle system: supercritical carbon dioxide enters from the turbine (2-2) inlet, the turbine (2-2) outlet is connected to the high-temperature regenerator (2-3) side inlet, the high-temperature regenerator (2-3) side outlet is connected to the low-temperature regenerator (2-4) side inlet, the low-temperature regenerator (2-4) side outlet is connected to the splitter (2-5) air inlet, an outlet branch of the splitter (2-5) is connected to the cooler (2-6) inlet, the cooler (2-6) outlet is connected to the main compressor (2-7) inlet, The outlet of the main compressor (2-7) is connected to the low-temperature regenerator (2-4) for heat exchange; another outlet branch is connected to the inlet of the carbon dioxide recompressor (2-8), the outlets of the low-temperature regenerator (2-4) and the recompressor (2-8) are connected to the inlet of the mixer (2-9), and the outlet of the mixer (2-9) is connected to a high-temperature regenerator (2-3) for heat exchange. Finally, the carbon dioxide at the outlet of the high-temperature regenerator (2-3) passes through the waste heat recovery device (2-1) and enters the turbine (2-2), completing a power generation cycle.

[0054] By combining chemical-looping hydrogen-electricity cogeneration technology with fuel cells, this invention allows for the adjustment of operating modes and switching of power generation methods based on the needs of hydrogen refueling and charging stations. This device also prevents carbon deposition on the anode of the SOFC and, based on the principles of chemical-looping technology, enables efficient carbon capture, achieving integrated system emissions reduction. Finally, the system's waste heat is used to couple to a supercritical carbon dioxide Brayton cycle for power generation, further improving energy efficiency.

[0055] In summary, the core device provided by the present invention includes an air reactor (1-3), a fuel reactor (1-4), a steam reactor (1-8), a waste heat boiler (1-7), a fuel cell module (1-10), a carbon dioxide main compressor (2-7), a recompressor (2-8), a turbine (2-2), a waste heat recovery device (2-1), a high-temperature regenerator (2-3), and a low-temperature regenerator (2-4). The air reactor, fuel reactor, and steam reactor form a cycle, which achieves the purpose of power generation while also providing hydrogen for the fuel cell; the supercritical carbon dioxide Brayton cycle recycles the waste heat of the flue gas to generate electricity again, thereby improving energy utilization.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A distributed clean hydrogen and power cogeneration device, characterized in that: The device couples three systems: a chemical chaining hydrogen-power cogeneration system, a fuel cell module, and a supercritical carbon dioxide Brayton cycle to form an integrated hydrogen-power cogeneration device: The chemical chain hydrogen and power cogeneration system (CLHG) comprises an air reactor (1-3), a fuel reactor (1-4), a steam reactor (1-8), a waste heat boiler (1-7), compressors (1-1, 1-2, 1-11) and turbines (1-5, 1-6, 1-9); the first inlet of the air reactor (1-3) is input with air compressed by the compressor (1-1), the second inlet of the air reactor (1-3) is connected to the second outlet of the steam reactor (1-8), the first outlet of the air reactor (1-3) is connected to the second inlet of the fuel reactor (1-4), and the fuel is supplied by the compressor (1-1) to the steam reactor (1-8). -2) is connected to the first inlet of the fuel reactor (1-4); the second outlets of the air reactor (1-3) and the fuel reactor (1-4) generate electricity through the turbines (1-5 and 1-6), and then recover high-quality heat energy through the waste heat boiler (1-7), and then are connected to the second inlet of the supercritical carbon dioxide Brayton cycle waste heat recovery device (2-1) described below; the external water is pressurized by the pump and enters the waste heat boiler (1-7) for heat exchange, and then is connected to the second inlet of the steam reactor (1-8); the first outlet of the steam reactor (1-8) is hydrogen, which generates electricity through the turbine (1-9) and then enters the fuel cell module (1-10); The supercritical carbon dioxide Brayton cycle system (s-CO2 cycle) includes a carbon dioxide main compressor (2-7), a recompressor (2-8), a turbine (2-2), a waste heat recovery device (2-1), a high-temperature regenerator (2-3) and a low-temperature regenerator (2-4); supercritical carbon dioxide enters from the turbine (2-2) inlet, the turbine (2-2) outlet is connected to the high-temperature regenerator (2-3) side inlet, the high-temperature regenerator (2-3) side outlet is connected to the low-temperature regenerator (2-4) side inlet, the low-temperature regenerator (2-4) side outlet is connected to the splitter (2-5) inlet, and one outlet branch of the splitter (2-5) is connected to the cooling air outlet. The inlet of the splitter (2-6) is connected to the inlet of the cooler (2-6), the outlet of the cooler (2-6) is connected to the inlet of the main compressor (2-7), and the outlet of the main compressor (2-7) is connected to the low-temperature regenerator (2-4) for heat exchange; another outlet branch of the splitter (2-5) is connected to the inlet of the carbon dioxide recompressor (2-8), the outlets of the low-temperature regenerator (2-4) and the recompressor (2-8) are connected to the inlet of the mixer (2-9), and the outlet of the mixer (2-9) is connected to a high-temperature regenerator (2-3) for heat exchange; finally, the carbon dioxide at the outlet of the high-temperature regenerator (2-3) passes through the waste heat recovery device (2-1) and enters the turbine (2-2), completing a power generation cycle.

2. A distributed clean hydrogen and power cogeneration device according to claim 1, characterized in that: The flue gas from the air reactor, the fuel reactor and the steam reactor is passed through a turbine to generate electricity.

3. A distributed clean hydrogen and power cogeneration device according to claim 2, characterized in that: The waste heat of the flue gas emitted by the air reactor, the fuel reactor and the fuel cell cathode is recovered and reused.

4. A distributed clean hydrogen and power cogeneration device according to claim 3, characterized in that: The recovered waste heat is used to heat feed water and carbon dioxide working fluid.

5. The distributed clean hydrogen and power cogeneration device according to claim 1, characterized in that: The water vapor generated by the anode reaction of the fuel cell is recovered and used together with the new water pumped in as the feed to the steam reactor.

6. A distributed clean hydrogen and power cogeneration device according to claim 1, characterized in that: The fuel and air preheating utilizes low-grade waste heat after heat exchange between the chemical chain hydrogen and power cogeneration system and the fuel cell module to provide part or all of the heat.

7. The distributed clean hydrogen and power cogeneration device according to claim 1, characterized in that: The device provides hydrogen and electricity to meet different needs. The specific implementation method is to switch between three operating modes through program control: (1) During periods of high hydrogen demand, the device adopts the first operating mode for hydrogen production only: the shut-off valve (1) is closed, so that the hydrogen produced by the chemical chain hydrogen and power cogeneration system (CLHG) does not flow into the fuel cell module, but is directly sent to the hydrogen storage system for storage; the first solenoid valve (2) and the second solenoid valve (3) are closed, the fuel cell module and the s-CO2 cycle do not operate, and at the same time, the electricity generated by the chemical chain hydrogen and power cogeneration system (CLHG) flue gas after passing through the turbine is also fully used for hydrogen production by electrolysis of water; in this mode, the hydrogen supply can be met to the greatest extent; (2) During periods of high electricity demand, the system uses the second power generation mode only for power generation: the shut-off valve (1), the first solenoid valve (2) and the second solenoid valve (3) are opened, so that the entire device operates efficiently according to the established mode; all hydrogen produced by the chemical chain hydrogen and power cogeneration system (CLHG) enters the fuel cell module as fuel, and the flue gas of the chemical chain hydrogen and power cogeneration system (CLHG) and the fuel cell is used to heat the carbon dioxide working medium of the s-CO2 cycle; in this mode, all three systems generate electricity, no hydrogen storage is performed, and the maximum demand for electricity is met; (3) When the demand for hydrogen and electricity is between the above two, the device adopts the third power generation mode to flexibly control the hydrogen and electricity production: open the stop valve (1), the first solenoid valve (2) and the second solenoid valve (3) and open each ball valve (①~⑤) as needed, so that part of the hydrogen produced by the chemical chain hydrogen and electricity cogeneration system (CLHG) enters the fuel cell module, and the remaining hydrogen enters the hydrogen storage system for storage; in this mode, the device can allocate the amount of hydrogen and electricity produced according to the demand of the internal power grid to achieve the purpose of cogeneration of the device.

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