A scheduling hydrogen production system coupling solar energy storage and adsorption enhanced methane steam reforming

Abstract

This invention belongs to the field of energy and chemical engineering, specifically relating to a dispatchable hydrogen production system that couples solar energy storage and adsorption-enhanced methane steam reforming. The system includes a reaction module, a heat exchange module, and a storage module; its operation modes are divided into daytime and nighttime modes; the reaction module includes a calcination reactor, a first gas-solid separator, a first adsorption-enhanced methane reforming reactor, a second gas-solid separator, a carbonation reactor, a third gas-solid separator, a second adsorption-enhanced methane reforming reactor, and a fourth gas-solid separator; the heat exchange module includes 12 heat exchangers and 2 turbines. This invention uses renewable solar energy as the system's energy source and calcium-based materials as the energy storage medium and adsorption-enhanced methane steam reforming medium, enabling continuous utilization of solar energy and dispatchable production of high-purity hydrogen. This is of great significance for promoting the utilization of renewable energy and the production of clean energy, and for building a clean and low-carbon energy system.

Description

Technical Field

[0001] This invention belongs to the field of energy and chemical engineering, and specifically relates to a dispatching hydrogen production system that couples solar energy storage with adsorption-enhanced methane steam reforming. Background Technology

[0002] Hydrogen energy is a clean and efficient secondary energy source. Due to its abundant reserves and potential for zero carbon emissions, it has become an important research direction in the energy field in recent years. Currently, industrial hydrogen production mainly relies on technologies such as coal gasification, methane steam reforming, and water electrolysis. Among these, methane steam reforming is widely used due to its high conversion efficiency and low hydrogen production cost. However, this traditional process consumes large amounts of fossil fuels and is accompanied by significant carbon dioxide emissions, placing considerable pressure on the environment. With the increasing global demand for clean energy and the establishment of carbon neutrality goals, developing efficient hydrogen production technologies that can reduce carbon emissions and combine with renewable energy sources is particularly important.

[0003] Adsorption-enhanced steam reforming of methane (SE-SMR) is an advanced hydrogen production technology that has attracted widespread attention in recent years. By dynamically removing carbon dioxide generated in the reaction through adsorbents, this technology breaks the constraints of reaction equilibrium, thereby significantly improving hydrogen yield and reaction efficiency. In existing research, calcium-based materials (such as CaO) are widely used to adsorb carbon dioxide, undergoing a carbonation reaction (CaO + CO2 → CaCO3) under high-temperature conditions to achieve efficient capture of carbon dioxide.

[0004] Solar energy, as a clean and renewable energy source, is gradually becoming an important energy source in the industrial sector due to its widespread availability and low-carbon characteristics. However, the intermittent and fluctuating nature of solar energy leads to poor energy supply stability, making it difficult to meet the stable energy supply demands of industry. Existing research suggests that solar energy storage technologies can address this issue, including latent heat storage, sensible heat storage, and thermochemical storage. Among these, thermochemical storage, using calcium-based materials as a medium, is widely used in concentrated solar power generation due to its low cost and high heat storage density, aiming to achieve stable storage and supply of solar energy.

[0005] In summary, existing technologies have been extensively studied in the fields of adsorption-enhanced methane steam reforming for hydrogen production and solar energy storage for power generation. However, there is a lack of research on how to combine renewable energy with adsorption-enhanced methane steam reforming for hydrogen production. Therefore, exploring the efficient application of renewable energy in the hydrogen production process is an effective direction for promoting the further development of this field. Summary of the Invention

[0006] In view of the problems and shortcomings of the existing technology, the purpose of this invention is to provide a dispatching hydrogen production system that couples solar energy storage and adsorption-enhanced methane steam reforming.

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

[0008] This invention provides a dispatchable hydrogen production system that couples solar energy storage and adsorption-enhanced methane steam reforming, including a reaction module, a heat exchange module, and a storage module; the operating modes are divided into daytime mode and nighttime mode;

[0009] The reaction module includes a calcination reactor, a first gas-solid separator, a first adsorption-enhanced methane reforming reactor, a second gas-solid separator, a carbonation reactor, a third gas-solid separator, a second adsorption-enhanced methane reforming reactor, and a fourth gas-solid separator. The inlets of all gas-solid separators are connected to the reactor outlets. The two outlets of the third and fourth gas-solid separators are both connected to heat exchangers. The heat exchange module includes 12 heat exchangers and 2 turbines. The inlets and outlets of the heat exchangers are directly or indirectly connected to the gas-solid separator outlets and reactor inlets, respectively. The inlet of the first turbine is connected to the hot outlet of the seventh heat exchanger, the outlet of the first turbine is connected to the inlet of the CO2 high-pressure gas cylinder, the inlet of the second turbine is connected to the cold outlet of the eleventh heat exchanger, and the outlet of the second turbine is connected to the cold inlet of the twelfth heat exchanger.

[0010] In daytime mode, solid CaCO3 absorbs heat from a concentrating solar receiver in a calcination reactor and is calcined to produce solid CaO and CO2 gas. A portion of the solid CaO is fed into a first adsorption-enhanced methane reforming reactor to generate solid CaCO3, which is then returned to the calcination reactor for further calcination. The remaining solid CaO is directly stored in a CaO storage tank. Simultaneously, the first adsorption-enhanced methane reforming reactor absorbs solar heat, and CH4 and H2O react to produce H2 gas. The waste heat carried by the products in the calcination reactor and the first adsorption-enhanced methane reforming reactor is recovered and utilized through a first heat exchanger, a second heat exchanger, a third heat exchanger, and a fourth heat exchanger.

[0011] In night mode, high-pressure CO2 gas from the high-pressure CO2 cylinder enters the second turbine to release energy and generate electricity. It then enters the carbonation reactor to react with a portion of the solid CaO transported from the CaO storage tank, releasing heat through a carbonation reaction. The reaction products provide heat for the methane steam reforming reaction. At the same time, the remaining solid CaO transported from the CaO storage tank directly enters the second adsorption-enhanced methane reforming reactor to participate in the reaction. In addition, the electrical energy generated by the first and second turbines supplements the heat source for the second adsorption-enhanced methane reforming reactor through electric heating, ensuring the complete reaction.

[0012] Furthermore, the calcination reactor is used to receive tower-type concentrated solar radiation to decompose the reactant CaCO3 particles into CaO and CO2 through endothermic reaction, storing solar energy in the form of chemical energy and sensible heat. The carbonation reactor is indirectly connected to the CaO storage tank and the CO2 high-pressure gas cylinder, and is used to carry out the carbonation reaction of CaO, releasing the energy stored in the form of chemical energy as an energy source for the adsorption-enhanced methane reforming reaction. The first adsorption-enhanced methane reforming reactor and the second adsorption-enhanced methane reforming reactor are used for the methane steam reforming reaction to produce hydrogen, and are connected to the outlet of each reactor by a gas-solid separator to separate the gas phase and solid phase of the reaction products, which is convenient for storage and transportation.

[0013] Furthermore, in daytime mode, the CO2 gas generated by the calcination reactor enters the first heat exchanger to exchange heat with the ambient temperature liquid water in the input system, causing it to form water vapor which enters the first adsorption-enhanced methane reforming reactor. Then, the CO2 gas continues to enter the fourth heat exchanger to exchange heat with the CH4 gas in the input system.

[0014] Furthermore, in night mode, the CaO and CO2 gases in the carbonation reactor react to release heat. The heat is carried out of the carbonation reactor in the form of sensible heat by the product CaCO3 solid and the remaining CO2 gas. After being separated by the third gas-solid separator, the heat released by the carbonation reaction is transferred to the H2O input into the system through the seventh and eighth heat exchangers, respectively, to provide heat for the methane steam reforming reaction. The heat is then stored in the CaCO3 storage tank and the CO2 high-pressure gas cylinder, respectively.

[0015] Furthermore, the ratio of the amount of CaO solid generated by calcination in the calcination reactor that is stored in the CaO storage tank to the amount used for the first adsorption-enhanced methane reforming reaction is 7:2; the ratio of the amount of CaO solid in the CaO storage tank used for the carbonation reaction to the amount used for the second adsorption-enhanced methane reforming reaction is 3:2.

[0016] Furthermore, both the calcination reactor and the carbonation reactor are fluidized bed reactors, the calcination reactor is connected to a concentrating solar receiver, and both the first adsorption-enhanced methane reforming reactor and the second adsorption-enhanced methane reforming reactor are fixed bed reactors; the heat exchangers are both countercurrent shell-and-tube heat exchangers.

[0017] Furthermore, the storage module includes a CaCO3 storage tank, a CaO storage tank, a CO2 high-pressure gas cylinder, a cooler, and a compressor. One inlet of the CaCO3 storage tank is indirectly connected to the outlet of the carbonation reactor via a third gas-solid separator and an eighth heat exchanger. The other inlet of the CaCO3 storage tank is indirectly connected to the outlet of the second adsorption-enhanced methane reforming reactor via a fourth gas-solid separator, a ninth heat exchanger, a fifth heat exchanger, and a sixth heat exchanger. The outlet of the CaCO3 storage tank is connected to the top inlet of the calcination reactor via a second heat exchanger. The inlet of the CaO storage tank is indirectly connected to the outlet of the carbonation reactor via a first gas-solid separator and a first distributor. The outlet of the CaO storage tank is connected to the lower inlet of the carbonation reactor and the upper inlet of the second adsorption-enhanced methane reforming reactor via a second distributor. The outlet of the cooler is connected to the inlet of the compressor. The outlet of the compressor is connected to one inlet of the CO2 high-pressure gas cylinder. The outlet of the CO2 high-pressure gas cylinder is connected to the second turbine via a sixth heat exchanger and an eleventh heat exchanger.

[0018] Furthermore, the CaCO3 storage tank is an ambient temperature and atmospheric pressure storage tank, the CaO storage tank is a high temperature and atmospheric pressure storage tank, both are insulated storage tanks with a storage temperature of 700℃, and the CO2 high-pressure gas cylinder is an ambient temperature and high-pressure gas cylinder with a storage pressure of 75 bar.

[0019] Furthermore, the reaction medium in the calcination reactor is a solid calcium carbonate-based material; the reaction medium in the carbonation reactor is a solid calcium oxide-based material and carbon dioxide gas; the reaction medium in the first adsorption-enhanced methane reforming reactor and the second adsorption-enhanced methane reforming reactor is methane gas, liquid water and solid calcium oxide particles, and the catalyst packed in the reactor is a Ni-based catalyst.

[0020] Furthermore, the solid calcium carbonate-based material is solid calcium carbonate particles; the solid calcium oxide-based material is solid calcium oxide particles.

[0021] Furthermore, when there is sufficient solar energy during the day, the first adsorption-enhanced methane steam reforming reactor is heated by solar energy, while at night when there is no solar energy, the second adsorption-enhanced methane steam reforming reactor is heated by the heat released from the carbonation reactor.

[0022] Furthermore, the sum of the solar power input of the calcination reactor and the first adsorption-enhanced methane reforming reactor is 100MW; the temperature of the calcination reactor is 900℃ and the pressure is 1bar; the ratio of CH4:H2O in the first adsorption-enhanced methane reforming reactor and the second adsorption-enhanced methane reforming reactor is 1:2 by volume, the reaction temperature is 650℃, and the reaction pressure is 1bar.

[0023] Furthermore, the storage temperature inside the CaO storage tank is 700℃; the storage pressure inside the CO2 high-pressure cylinder is 75 bar.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) The system’s two operating modes during the day and at night are beneficial to storing a portion of solar energy in the form of chemical energy through the CaCO3 calcination reaction when there is sufficient sunlight. This energy can be used as a reserve heat source for the methane reforming hydrogen production reaction when there is insufficient sunlight or at night. This overcomes the intermittent nature of solar energy, realizes the dispatchability of solar energy utilization, and completes the continuous production of high-purity hydrogen.

[0026] (2) The system utilizes solid CaO particles to adsorb and enhance the CO2 gas produced by the methane steam reforming reaction, which promotes the generation of hydrogen and can also produce high-purity hydrogen.

[0027] (3) The system utilizes heat exchange modules, especially heat exchange modules including 12 heat exchangers and 2 turbines. The inlet and outlet of the heat exchangers are directly or indirectly connected to the outlet of the gas-solid separator and the inlet of the reactor, respectively. The inlet of the first turbine is connected to the hot outlet of the seventh heat exchanger, the outlet of the first turbine is connected to the inlet of the CO2 high-pressure gas cylinder, the inlet of the second turbine is connected to the cold outlet of the eleventh heat exchanger, and the outlet of the second turbine is connected to the cold inlet of the twelfth heat exchanger, forming a heat exchange network to recover and utilize the waste heat of the material, which greatly improves the energy utilization rate of the system and realizes energy saving of the system. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the scheduling hydrogen production system of the present invention, which couples solar energy storage and adsorption-enhanced methane steam reforming.

[0029] Figure 2 This is a model diagram of the calculation process of the system of the present invention in daytime mode;

[0030] Figure 3 This is a model diagram of the calculation process of the system of the present invention in night mode.

[0031] In the diagram: 1. Calcination reactor; 2. First adsorption-enhanced methane reforming reactor; 3. CaCO3 storage tank; 4. CaO storage tank; 5. CO2 high-pressure gas cylinder; 6. Carbonation reactor; 7. Second adsorption-enhanced methane reforming reactor; 8. First gas-solid separator S1; 9. Second gas-solid separator S2; 10. Third gas-solid separator S3; 11. Fourth gas-solid separator S4; 12. First heat exchanger HX1; 2. Second heat exchanger HX2; 3. Third heat exchanger HX3; 4. Fourth heat exchanger HX4; 5. Fifth heat exchanger HX5; 6. Sixth heat exchanger HX6; 7. Seventh heat exchanger HX7; 8. Eighth heat exchanger HX8; 9. Ninth heat exchanger HX9; 10. Tenth heat exchanger HX10; 11. Eleventh heat exchanger HX11; 12. Twelfth heat exchanger HX12; Cooler CL1; Compressor COMP; First turbine T1; Second turbine T2; First distributor SEU1; Second distributor SEU2. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] Example 1

[0034] This embodiment provides a dispatching hydrogen production system that couples solar energy storage and adsorption-enhanced methane steam reforming, as shown in the schematic diagram. Figure 1 As shown, it includes a reaction module, a heat exchange module, and a storage module; the operating modes are divided into daytime mode and nighttime mode;

[0035] The reaction module includes a calcination reactor 1, a first gas-solid separator S1, a first adsorption-enhanced methane reforming reactor 2, a second gas-solid separator S2, a carbonation reactor 6, a third gas-solid separator S3, a second adsorption-enhanced methane reforming reactor 7, and a fourth gas-solid separator S4. The inlets of all gas-solid separators are connected to the reactor outlets, and the two outlets of the third and fourth gas-solid separators are both connected to heat exchangers. Both the calcination reactor 1 and the carbonation reactor 6 are fluidized bed reactors. The calcination reactor 1 is connected to a concentrating solar receiver. The first adsorption-enhanced methane reforming reactor... Both the reforming reactor 2 and the second adsorption-enhanced methane reforming reactor 7 are fixed-bed reactors; the reaction medium in the calcination reactor 1 is a solid calcium carbonate-based material; the reaction medium in the carbonation reactor 6 is a solid calcium oxide-based material and carbon dioxide gas; the reaction medium in the first adsorption-enhanced methane reforming reactor 2 and the second adsorption-enhanced methane reforming reactor 7 is methane gas, liquid water, and solid calcium oxide particles, and the catalyst packed in the reactor is a Ni-based catalyst; the solid calcium carbonate-based material is solid calcium carbonate particles; the solid calcium oxide-based material is solid calcium oxide particles.

[0036] The heat exchange module includes 12 heat exchangers and 2 turbines. The inlet and outlet of the heat exchangers are directly or indirectly connected to the outlet of the gas-solid separator and the inlet of the reactor, respectively. The inlet of the first turbine T1 is connected to the hot outlet of the seventh heat exchanger HX7, and the outlet of the first turbine T1 is connected to the inlet of the CO2 high-pressure cylinder 5. The inlet of the second turbine T2 is connected to the cold outlet of the eleventh heat exchanger HX11, and the outlet of the second turbine T2 is connected to the cold inlet of the twelfth heat exchanger HX12. All heat exchangers are counter-flow shell-and-tube heat exchangers.

[0037] The storage module includes a CaCO3 storage tank 3, a CaO storage tank 4, a CO2 high-pressure cylinder 5, a cooler CL1, and a compressor COMP. The storage temperature in the CaO storage tank 4 is 700℃, and the storage pressure in the CO2 high-pressure cylinder 5 is 75 bar. One inlet of the CaCO3 storage tank 3 is indirectly connected to the outlet of the carbonation reactor 6 via a third gas-solid separator S3 and an eighth heat exchanger HX8. The other inlet of the CaCO3 storage tank 3 is indirectly connected to the outlet of the second adsorption-enhanced methane reforming reactor 7 via a fourth gas-solid separator S4, a ninth heat exchanger HX9, a fifth heat exchanger HX5, and a sixth heat exchanger HX6. The outlet of tank 3 is connected to the top inlet of calcination reactor 1 via the second heat exchanger HX2; the inlet of CaO storage tank 4 is indirectly connected to the outlet of carbonation reactor 6 via the first gas-solid separator S1 and the first distributor SEU1 in sequence; the outlet of CaO storage tank 4 is connected to the lower inlet of carbonation reactor 6 and the upper inlet of second adsorption-enhanced methane reforming reactor 7 via the second distributor SEU2; the outlet of cooler CL1 is connected to the inlet of compressor COMP; the outlet of compressor COMP is connected to one of the inlets of CO2 high-pressure cylinder 5; the outlet of CO2 high-pressure cylinder 5 is connected to the second turbine T2 via the sixth heat exchanger HX6 and the eleventh heat exchanger HX11 in sequence.

[0038] In daytime mode, solid CaCO3 absorbs heat from a concentrating solar receiver in calcination reactor 1 at 900°C and 1 bar, calcining to produce solid CaO and CO2 gas. The ratio of the amount of solid CaO produced in calcination reactor 1 that is stored in CaO storage tank 4 to the amount used in the first adsorption-enhanced methane reforming reaction is 7:2. The solid CaO then enters the first adsorption-enhanced methane reforming reactor 2 to produce solid CaCO3, which is then re-entering calcination reactor 1 for further calcination. The remaining solid CaO is directly stored in CaO storage tank 4. The CO2 gas produced in calcination reactor 1 enters the first heat exchanger HX1. The CO2 gas exchanges heat with the ambient temperature liquid water in the input system, forming water vapor which enters the first adsorption-enhanced methane reforming reactor 2. Then, the CO2 gas continues to enter the fourth heat exchanger HX4 to exchange heat with the CH4 gas in the input system. At the same time, the first adsorption-enhanced methane reforming reactor 2 absorbs solar heat. The volume ratio of CH4 to H2O in the reactor is 1:2, and a reaction occurs at 650°C and 1 bar to produce H2 gas. The residual heat carried by the products in the calcination reactor 1 and the first adsorption-enhanced methane reforming reactor 2 is recovered and utilized through the first heat exchanger HX1, the second heat exchanger HX2, the third heat exchanger HX3, and the fourth heat exchanger HX4.

[0039] In night mode, high-pressure CO2 gas from high-pressure CO2 cylinder 5 enters the second turbine T2 to release energy for power generation, and then enters the carbonation reactor 6. The ratio of CaO solids in CaO storage tank 4 used for the carbonation reaction and for the second adsorption-enhanced methane reforming reaction is 3:2. The CaO solids transported from CaO storage tank 4 enter the carbonation reactor 6 and react with CO2 gas to release heat through a carbonation reaction. The reaction products provide heat for the methane steam reforming reaction. The reaction between CaO and CO2 gas in the carbonation reactor 6 releases heat, which is carried out of the carbonation reactor 6 in the form of sensible heat by the product CaCO3 solids and the remaining CO2 gas. The mixture then passes through the third gas-solid separator S3. After passing through the seventh heat exchanger HX7 and the eighth heat exchanger HX8, the heat released from the carbonation reaction is transferred to the H2O input into the system, providing heat for the methane steam reforming reaction. The heat is then stored in a CaCO3 storage tank and a CO2 high-pressure cylinder, respectively. At the same time, the solid CaO transported from the CaO storage tank 4 directly enters the second adsorption-enhanced methane reforming reactor 7 for adsorption-enhanced methane reforming reaction. The volume ratio of CH4 to H2O in the reactor is 1:2, and the reaction is carried out at 650°C and 1 bar to produce H2 gas. In addition, the electrical energy generated by the first turbine T1 and the second turbine T2 supplements the heat source of the second adsorption-enhanced methane reforming reactor 7 through electric heating, so that the reaction can proceed to completion.

[0040] When there is sufficient solar energy during the day, the first adsorption-enhanced methane steam reforming reactor 2 is heated by solar energy. When there is no solar energy at night, the second adsorption-enhanced methane steam reforming reactor 7 is heated by the heat released from the carbonation reactor.

[0041] During production, in daytime mode, the CaCO3 solid in CaCO3 storage tank 3 is preheated by the second heat exchanger HX2 and then enters the calcination reactor 1. The calcination reactor 1 absorbs the heat generated by the concentrating solar receiver to calcine the CaCO3 to generate CaO solid and CO2 gas. The ratio of the amount of CaO solid generated by calcination reactor 1 entering CaO storage tank 4 for storage and the amount used for the first adsorption-enhanced methane reforming reaction is 7:2. The CaO solid is separated by the first gas-solid separator S1 and then passes through the first splitter SEU1. A portion of the CaO solid enters the first adsorption-enhanced methane reforming reactor 2 to adsorb the CO2 gas generated by the reaction and generate CaCO3 solid. After being separated by the second gas-solid separator S2, it re-enters the calcination reactor 1 for calcination, forming a cycle of calcium-based materials. The remaining CaO solid directly enters CaO storage tank 4 for storage. The CO2 gas generated in the calcination reactor 1 is separated by the first gas-solid separator S1 and then enters the first heat exchanger HX1 to exchange heat with the room-temperature liquid water in the input system, forming water vapor which enters the first adsorption-enhanced methane reforming reactor 2. The CO2 gas then continues to enter the fourth heat exchanger HX4 to exchange heat with the CH4 gas in the input system, and then enters the cooler CL1 for cooling. After being compressed to 75 bar by the compressor COMP, it is stored in the CO2 high-pressure gas cylinder 5. At the same time, the first adsorption-enhanced methane reforming reactor 2 also absorbs solar heat to carry out a methane water vapor reforming reaction. The CaCO3 solid and H2 gas produced by the reaction are separated by the second gas-solid separator S2. The CaCO3 solid directly enters the calcination reactor 1 for calcination, while the H2 gas is cooled by the third heat exchanger HX3 and the second heat exchanger HX2 to obtain high-purity H2 gas.

[0042] In night mode, high-pressure CO2 gas from high-pressure CO2 cylinder 5 passes through the sixth heat exchanger HX6 and the eleventh heat exchanger HX11 before entering turbine T2 to release energy for power generation. It then enters the twelfth heat exchanger HX12 for preheating before entering the carbonation reactor 6. The ratio of CaO solids in CaO storage tank 4 used for the carbonation reaction and for the second adsorption-enhanced methane reforming reaction is 3:2. A portion of the high-temperature CaO solids from CaO storage tank 4, transported through the second distributor SEU2, enters the carbonation reactor 6 and reacts with CO2 gas to produce CaCO3 solids, releasing a large amount of heat. This heat is carried out of the carbonation reactor 6 in sensible heat form by the product CaCO3 solids and the remaining CO2 gas. After separation by gas-solid separator S3, the heat released from the carbonation reaction is transferred to the H2O input into the system through the seventh heat exchanger HX7 and the eighth heat exchanger HX8. The methane steam reforming reaction provides heat, which is then stored in CaCO3 storage tank 4 and CO2 high-pressure cylinder 5, respectively. Simultaneously, the remaining high-temperature CaO solid from CaO storage tank 4 directly enters the second adsorption-enhanced methane reforming reactor 7. The ambient-temperature liquid water input into the system absorbs the residual heat of the reformed CaCO3 solid through the ninth heat exchanger HX9, and then sequentially passes through the eighth heat exchanger HX8 and the seventh heat exchanger HX7 to absorb heat before entering the second adsorption-enhanced methane reforming reactor 7 to carry a large amount of heat for the adsorption-enhanced methane reforming reaction. Meanwhile, the CH4 gas input into the system is preheated through the fifth heat exchanger HX5 and the tenth heat exchanger HX10 before entering the second adsorption-enhanced methane reforming reactor 7 to participate in the reaction. The electrical energy generated by the first turbine T1 and the second turbine T2 is used as a supplementary heat source for the second adsorption-enhanced methane reforming reactor 7 through electric heating to ensure the complete progress of the reforming reaction.

[0043] Example 2

[0044] This embodiment provides Aspen simulation tests performed on the daytime and nighttime modes of the system of the present invention, respectively.

[0045] The system was simulated using Aspen plus V11 software under the operating conditions shown in Table 1 below:

[0046] Table 1: System Simulation Operation Parameter Settings

[0047]

[0048] like Figure 2 The figure shows the calculation process model of the system in daytime mode. The calculated values ​​of the main parameters such as temperature, pressure, flow rate, molar enthalpy, and molar entropy of each material are shown in Table 2 below:

[0049] Table 2: Key parameter values ​​of each logistics component during system operation in daytime mode

[0050]

[0051]

[0052] Based on the above results, energy analysis of the system in daytime mode reveals that when 100MW of solar energy is introduced into the system, 95.75MW of solar energy is directly applied to the calcination reactor, and 4.25MW of solar energy is directly applied to the first adsorption-enhanced methane reforming hydrogen production reactor. In the calcination reactor, 52.93% of the solar energy is stored as chemical energy in the products CaO and CO2, 21.17% of the solar energy indirectly enters the adsorption-enhanced reforming reactor through the calcination product CaO to power the reforming reaction, and the remaining 47.06% of the solar energy is carried as sensible heat by the reaction products CaO and CO2. Additionally, 60.70% of the solar energy absorbed by the adsorption-enhanced methane reforming reactor is also carried as sensible heat by the reaction products. This sensible heat can be recovered through a heat exchange network for preheating the reactants in the calcination and adsorption-enhanced methane reforming reactions, achieving efficient energy utilization. The waste heat recovery efficiency of the heat exchange network in daytime mode is 62.71%.

[0053] In daytime mode, 60.26% of the solar energy input into the system is stored as the reaction products CaO and CO2, serving as the energy source for nighttime mode; the system energy loss rate is 38.06%, consisting of compression loss (12.46%), cooling loss (10.39%), and waste heat (15.19%); the system can produce a hydrogen molar flow rate of 474.99 mol / s in daytime mode, and the system's daytime hydrogen production rate is 66.88%.

[0054] like Figure 3 The figure shows the calculation process model of the system in night mode. The calculated values ​​of the main parameters such as temperature, pressure, flow rate, molar enthalpy, and molar entropy of each stream are shown in Table 3 below:

[0055] Table 3: Key parameter values ​​of each logistics item when the system is running in night mode

[0056]

[0057]

[0058] Based on the above results, energy analysis of the system in nighttime mode reveals that the system energy in nighttime mode originates from solar energy stored in daytime mode. In nighttime mode, the carbonation reaction releases 10.67 MW of energy, of which 57.67% is used to heat the reactants to the reaction temperature, and the remaining 42.32% is carried out of the calcination reactor by unreacted reactants and reaction products, used to evaporate and preheat H2O entering the reforming reactor. Waste heat from the carbonation and reforming reactors is recovered through a heat exchanger network for preheating the reactants in the carbonation and adsorption-enhanced methane reforming reactions. The waste heat recovery efficiency of the heat exchanger network in nighttime mode is 84.85%. The adsorption-enhanced methane reforming reactor, after preheating the reactants, still requires a heat load of 1.77 MW, provided by turbines T1 and T2. In night mode, the system's energy loss rate is 13.75%, consisting of CaO storage loss (4.47%) and waste heat (9.28%). The system can produce a hydrogen molar flow rate of 474.99 mol / s in night mode, and the system's nighttime hydrogen production rate is 50.38%.

[0059] Combining the results of the two operating modes, the following formula can be used to calculate the system's performance under 100MW solar power and 12h sunshine hours:

[0060] System flow conservation condition:

[0061] F CA，clc =F CA，SMR，day +F CA，SMR，night +F CA，carb ,

[0062] Among them, F CA,c1c : Ca flow rate in the calcination reactor, F CA,SMR,day Ca flow rate and F in the adsorption-enhanced reforming reactor under daytime mode CA,SMR,night Ca flow rate and F in the adsorption-enhanced reforming reactor under daytime mode CA,carb Ca flow rate in the carbonation reactor;

[0063] System energy conditions:

[0064] Q clc +Q SMR，day =Q sun

[0065] Q carb -Q SMR，night >0,

[0066] Among them, Q c1c : Calcination reaction heat load, Q SMR,day Heat load of daytime adsorption-enhanced reforming reaction, Q sun Solar energy input, Q SMR,night Heat load of daytime adsorption-enhanced reforming reaction, Qcarb : Carbonation reaction heat load;

[0067] System evaluation metrics:

[0068] Solar hydrogen production efficiency:

[0069]

[0070] Where, n H2 : The molar amount of hydrogen produced by the system, HHV H2 : Calorific value of hydrogen, n CH4 : The molar amount of methane input to the system, HHV CH4 : Calorific value of methane, q solar : System solar input load, q comp System compressor input load, HHV H2 It is 286 kJ / mol, HHV CH4 With a yield of 888.3 kJ / mol, the total hydrogen production rate for the day is 57.47%.

[0071] In summary, the dispatchable hydrogen production system coupled with solar energy storage and adsorption-enhanced methane steam reforming provided by this invention is based on the concept of existing solar energy storage power generation systems. It utilizes calcium-based materials as energy storage and CO2 adsorption materials, and couples solar energy storage with adsorption-enhanced methane steam reforming hydrogen production systems. This overcomes the intermittent nature of solar energy and achieves the goal of producing high-purity hydrogen by dispatchable solar energy throughout the day. It has broad prospects for promotion and application in the fields of clean and renewable energy development and methane hydrogen production technology.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Those skilled in the art can modify or make equivalent substitutions to the technical solutions of the present invention based on the concept of the present invention, without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A dispatchable hydrogen production system coupling solar energy storage and adsorption-enhanced methane steam reforming, characterized in that, It includes a reaction module, a heat exchange module, and a storage module; the operating modes are divided into daytime mode and nighttime mode; The reaction module includes a calcination reactor, a first gas-solid separator, a first adsorption-enhanced methane reforming reactor, a second gas-solid separator, a carbonation reactor, a third gas-solid separator, a second adsorption-enhanced methane reforming reactor, and a fourth gas-solid separator. The inlets of all gas-solid separators are connected to the reactor outlets. The two outlets of the third and fourth gas-solid separators are both connected to heat exchangers. The heat exchange module includes 12 heat exchangers and 2 turbines. The inlets and outlets of the heat exchangers are directly or indirectly connected to the gas-solid separator outlets and reactor inlets, respectively. The inlet of the first turbine is connected to the hot outlet of the seventh heat exchanger, and the outlet of the first turbine is connected to the inlet of the CO2 high-pressure cylinder. The inlet of the second turbine is connected to the cold outlet of the eleventh heat exchanger, and the outlet of the second turbine is connected to the cold inlet of the twelfth heat exchanger. The storage module includes a CaCO3 storage tank, a CaO storage tank, a CO2 high-pressure cylinder, a cooler, and a compressor. One inlet of the CaCO3 storage tank is indirectly connected to the outlet of the carbonation reactor via a third gas-solid separator and an eighth heat exchanger. The other inlet of the CaCO3 storage tank is indirectly connected to the outlet of the second adsorption-enhanced methane reforming reactor via a fourth gas-solid separator, a ninth heat exchanger, a fifth heat exchanger, and a sixth heat exchanger. The outlet of the CaCO3 storage tank is connected to the top inlet of the calcination reactor via a second heat exchanger. The inlet of the CaO storage tank is indirectly connected to the outlet of the carbonation reactor via a first gas-solid separator and a first distributor. The outlet of the CaO storage tank is connected to the lower inlet of the carbonation reactor and the upper inlet of the second adsorption-enhanced methane reforming reactor via a second distributor. The outlet of the cooler is connected to the compressor inlet. The compressor outlet is connected to one inlet of the CO2 high-pressure gas cylinder. The outlet of the CO2 high-pressure gas cylinder is connected to the second turbine via a sixth heat exchanger and an eleventh heat exchanger. In daytime mode, solid CaCO3 absorbs heat from a concentrating solar receiver in a calcination reactor and is calcined to produce solid CaO and CO2 gas. A portion of the solid CaO is fed into a first adsorption-enhanced methane reforming reactor to generate solid CaCO3, which is then returned to the calcination reactor for further calcination. The remaining solid CaO is directly stored in a CaO storage tank. Simultaneously, the first adsorption-enhanced methane reforming reactor absorbs solar heat, and CH4 and H2O react to produce H2 gas. The waste heat carried by the products in the calcination reactor and the first adsorption-enhanced methane reforming reactor is recovered and utilized through a first heat exchanger, a second heat exchanger, a third heat exchanger, and a fourth heat exchanger. In night mode, high-pressure CO2 gas from the high-pressure CO2 cylinder enters the second turbine to release energy and generate electricity. It then enters the carbonation reactor to react with a portion of solid CaO transported from the CaO storage tank, releasing heat through a carbonation reaction. The reaction products provide heat for the methane steam reforming reaction. Simultaneously, the remaining solid CaO transported from the CaO storage tank directly enters the second adsorption-enhanced methane reforming reactor to participate in the reaction. Furthermore, the electrical energy generated by the first and second turbines supplements the heat source for the second adsorption-enhanced methane reforming reactor through electric heating, ensuring the reaction proceeds completely. The ratio of the amount of CaO solid generated by calcination in the calcination reactor to the amount stored in the CaO storage tank and used for the first adsorption-enhanced methane reforming reaction is 7:2; the ratio of the amount of CaO solid in the CaO storage tank used for the carbonation reaction and used for the second adsorption-enhanced methane reforming reaction is 3:

2.

2. The dispatching hydrogen production system coupled with solar energy storage and adsorption-enhanced methane steam reforming according to claim 1, characterized in that, In daytime mode, the CO2 gas generated by the calcination reactor enters the first heat exchanger and exchanges heat with the ambient temperature liquid water in the input system, causing it to form water vapor which enters the first adsorption-enhanced methane reforming reactor. Then, the CO2 gas continues to enter the fourth heat exchanger and exchanges heat with the CH4 gas in the input system.

3. The dispatch hydrogen production system that couples solar energy storage and adsorbent enhanced methane steam reforming of claim 1, wherein, In night mode, CaO and CO2 gas react in the carbonation reactor to release heat. The heat is carried out of the carbonation reactor in the form of sensible heat by the product CaCO3 solid and the remaining CO2 gas. After being separated by the third gas-solid separator, the heat released by the carbonation reaction is transferred to the H2O input into the system through the seventh and eighth heat exchangers to provide heat for the methane steam reforming reaction. The heat is then stored in the CaCO3 storage tank and the CO2 high-pressure gas cylinder, respectively.

4. The dispatching hydrogen production system coupled with solar energy storage and adsorption-enhanced methane steam reforming according to claim 1, characterized in that, The reaction medium in the calcination reactor is a solid calcium carbonate-based material; the reaction medium in the carbonation reactor is a solid calcium oxide-based material and carbon dioxide gas; the reaction medium in the first adsorption-enhanced methane reforming reactor and the second adsorption-enhanced methane reforming reactor is methane gas, liquid water and solid calcium oxide particles, and the catalyst packed in the reactor is a Ni-based catalyst.

5. The dispatch hydrogen production system that couples solar energy storage and adsorbent enhanced methane steam reforming of claim 4, wherein, The solid calcium carbonate-based material is solid calcium carbonate particles; the solid calcium oxide-based material is solid calcium oxide particles.

6. The dispatch hydrogen production system that couples solar energy storage and adsorbent enhanced methane steam reforming of claim 1, wherein, When there is sufficient solar energy during the day, the first adsorption-enhanced methane reforming reactor is heated by solar energy. When there is no solar energy at night, the second adsorption-enhanced methane reforming reactor is heated by the heat released from the carbonation reactor.

7. The scheduling hydrogen production system of coupling solar energy storage and adsorbent enhanced methane steam reforming according to any one of claims 1-6, characterized in that, The sum of the solar power input of the calcination reactor and the first adsorption-enhanced methane reforming reactor is 100MW; the temperature of the calcination reactor is 900℃ and the pressure is 1 bar; the CH4:H2O ratio in the first adsorption-enhanced methane reforming reactor and the second adsorption-enhanced methane reforming reactor is 1:2 by volume, the reaction temperature is 650℃, and the reaction pressure is 1 bar.

8. The dispatch hydrogen production system that couples solar energy storage and adsorbent enhanced methane steam reforming of claim 7, wherein, The storage temperature in the CaO storage tank is 700℃; the storage pressure in the CO2 high-pressure cylinder is 75 bar.

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