Stable hydrogen production device and method for solid oxide electrolytic tank under fluctuating power supply

Abstract

The invention relates to a stable hydrogen production device and method for a solid oxide electrolytic cell under a fluctuating power supply, and the device comprises the fluctuating power supply, a first electric pile, a thermochemical module and a second electric pile, a fuel electrode gas inlet of the first electric pile is connected with a first gas output end, and a power supply end of the first electric pile is connected with the fluctuating power supply; a fuel electrode outlet of the first electric pile is connected with an inlet of the thermochemical module, and the first electric pile generates a first gas product based on first output gas of a first gas output end when the current input voltage is greater than a first preset voltage; and the thermochemical module performs hydrogen absorption and heat absorption reaction based on the first gas product to obtain a second gas product. And the second electric pile generates hydrogen meeting the preset concentration through electrolysis based on the second output gas of the second gas output end and the second gas product. Therefore, the problem that thermal management and gas component balance management of the system are insufficient under the fluctuating power supply condition is solved, the operation efficiency of the system is improved, and the complexity of system building is reduced.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical technology, and in particular to a device and method for stably producing hydrogen in a solid oxide electrolytic cell under a fluctuating power supply. Background Art

[0002] In recent years, my country has achieved remarkable and rapid development in the field of hydropower, wind and solar renewable energy power generation. Renewable energy is usually characterized by volatility and intermittency, which has caused difficulties in grid connection and the phenomenon of wind and solar abandonment. While wasting resources, it also seriously hinders the development of new energy technologies. Using renewable energy electricity for electrolytic hydrogen production can effectively improve the utilization rate of renewable energy. The produced hydrogen can be used in transportation, chemical industry, metallurgy and other fields; it can also be used for power generation when electricity is insufficient. SOEC electrolytic hydrogen production technology operates at high temperature (600-800℃) and has the lowest electrolysis energy consumption. SOEC stacks have three states of endothermic, exothermic and thermoneutral operation, which are mainly related to the operating voltage. When the stack is at the thermoneutral voltage, the stack does not absorb or release heat, and can achieve self-sustaining; when the voltage is higher than the thermoneutral voltage, the stack releases heat. The higher the voltage, the more heat is released, and the more hydrogen is produced; below the thermoneutral voltage, the stack needs to absorb heat from the outside. The lower the voltage, the more heat needs to be absorbed, and the less hydrogen is produced. Based on the above operating characteristics, when the power source fluctuates over time, the stack will be in a state of absorbing and releasing heat at different times; heat fluctuations will cause temperature fluctuations in the stack, which is not conducive to the long-life operation of the stack. And when the stack inlet gas composition and flow rate remain unchanged, the hydrogen concentration in the product will change over time; product composition fluctuations make system gas management more difficult.

[0003] In the related art, under the condition of fluctuating power supply, multiple parameters are effective for the temperature control of SOEC, including air flow rate, water vapor flow rate, inlet gas temperature, inlet gas composition, etc. For example, in related art 1, air flow rate and air inlet temperature are used to control the temperature change of SOEC: when the electrolysis power becomes higher and the stack is in an exothermic state, the excess heat is taken away by increasing the air flow rate; when the electrolysis power decreases and the stack is in an endothermic state, the air flow rate needs to be reduced, and electric heating is used to supplement the heat. For another example, in related art 2, the steam flow rate is used to adjust the temperature of the SOEC heat source: according to the change of solar power generation power, the stack is kept in a thermal neutral voltage state, and the SOEC water vapor flow rate is dynamically adjusted (the electrolysis current changes accordingly), fundamentally ensuring that the stack is in a thermal equilibrium state. For another example, related technology 3 uses a thermochemical heat storage module to regulate the temperature changes of SOEC in the endothermic and exothermic states. The principle is to use the temperature changes to affect the redox reaction of the energy storage material: when the SOEC voltage is higher than the thermoneutral voltage, the battery stack releases heat, and when the temperature rises to the critical temperature of the energy storage material, the energy storage module undergoes a reduction reaction to absorb heat and release oxygen; when the SOEC operating voltage is lower than the thermoneutral voltage, the battery stack absorbs heat, and when the temperature drops to the critical temperature of the energy storage material, the energy storage module undergoes an oxidation reaction to release heat and absorb oxygen.

[0004] However, the method of regulating the temperature by air flow rate in related technology 1 is a passive method for regulating the temperature of the battery stack, which requires the compressor to consume a large amount of additional electric energy to increase the air flow rate, and will not change the temperature of the SOEC heat source, but only dilutes the heat source heat, which leads to a significant increase in the system parasitic power and waste of heat energy, and the waste heat generated in the exothermic state is not effectively utilized. In related technology 2, when the water vapor flow rate of the SOEC inlet decreases, due to the uneven distribution of components inside the battery stack, the local reactant shortage of the battery is caused, which is easy to cause the battery stack failure, so very high requirements are put forward for the consistency of gas distribution inside the battery stack and the tolerance of local water vapor shortage of the battery. Related technology 3 needs to ensure the matching of the SOEC operating temperature and the critical reaction temperature of the heat storage material; and the coupling relationship between the modules is not close, and the oxygen absorption and release of the energy storage module need to be managed, which increases the complexity of the system; and the system of related technology 3 does not consider the problem of product components changing with fluctuating power supply. Therefore, under the conditions of fluctuating renewable energy power supply, effective SOEC thermal management and gas component balance management are still a challenge that needs to be solved urgently. Summary of the invention

[0005] The present invention provides a device and method for stable hydrogen production by a solid oxide electrolytic cell under fluctuating power supply. By applying a fluctuating power supply to a first electrolytic cell, a thermochemical module adaptively realizes the storage and release of hydrogen / heat, realizes the regulation of the temperature and product gas of the first electrolytic cell, and then continuously produces high-purity hydrogen through a second electrolytic cell operating under a stable power supply, thereby solving the problems of insufficient thermal management and gas component balance management of the system under fluctuating power supply conditions, improving the system operation efficiency, and reducing the complexity of system construction.

[0006] A first aspect of the present invention provides a stable hydrogen production device for a solid oxide electrolysis cell under a fluctuating power supply, comprising: a fluctuating power supply, a first fuel cell, a thermochemical module and a second fuel cell, wherein a fuel electrode air inlet of the first fuel cell is connected to a first gas output end, a power supply end of the first fuel cell is connected to the fluctuating power supply, a fuel electrode outlet of the first fuel cell is connected to an inlet of the thermochemical module, and when a current input voltage of the first fuel cell is greater than a first preset voltage, the first fuel cell generates a first gas product based on a first output gas at the first gas output end; the thermochemical module performs a hydrogen absorption and endothermic reaction based on the first gas product to obtain a second gas product; the fuel electrode air inlet of the second fuel cell is respectively connected to the outlet and the second gas output end of the thermochemical module, and the second fuel cell generates hydrogen meeting a preset concentration by electrolysis based on the second output gas at the second gas output end and the second gas product.

[0007] Furthermore, in some embodiments, when the current input voltage of the first fuel cell stack is less than or equal to the first preset voltage, the first fuel cell stack generates a third gas product based on the first output gas of the first gas output end; the thermochemical module performs a hydrogen release and exothermic reaction based on the third gas product to obtain a fourth gas product; and the second fuel cell stack generates hydrogen meeting the preset concentration or a synthetic gas of a preset concentration by electrolysis based on the second output gas and the fourth gas product.

[0008] Furthermore, in some embodiments, the stable hydrogen production device of the solid oxide electrolysis cell under the fluctuating power supply further includes: a power supply component, wherein the power supply component is connected to the second battery stack and is used to provide voltage when the second battery stack performs electrolysis.

[0009] Further, in some embodiments, the temperature of the thermochemical module is determined by the first gas product or the third gas product.

[0010] Furthermore, in some embodiments, the material in the thermochemical module is a metal material and / or a metal oxide material.

[0011] Furthermore, in some embodiments, the second output gas is water vapor with a preset flow rate or CO with a preset concentration. 2 .

[0012] According to the stable hydrogen production device of solid oxide electrolysis cell under fluctuating power supply provided by the embodiment of the present invention, by applying fluctuating power supply to the first electrolysis stack, the thermochemical module adaptively realizes the storage and release of hydrogen / heat, realizes the regulation of the temperature and product gas of the first electrolysis stack, and then realizes the continuous production of high-purity hydrogen through the second electrolysis stack working under stable power supply. The problem of insufficient thermal management and gas component balance management of the system under fluctuating power supply conditions is solved, the system operation efficiency is improved, and the complexity of system construction is reduced.

[0013] A second aspect of the present invention provides a method for stable hydrogen production from a solid oxide electrolysis cell under a fluctuating power supply, using a stable hydrogen production device for a solid oxide electrolysis cell under a fluctuating power supply as described in any one of the above items, wherein the method comprises: obtaining a current input voltage of the first battery stack; when the current input voltage is greater than a first preset voltage, the first battery stack generates a first gas product based on a first output gas at the first gas output end, so that the thermochemical module performs a hydrogen absorption and endothermic reaction based on the first gas product to obtain a second gas product; and using a power supply component to power the second battery stack, so that the second battery stack generates hydrogen meeting the preset concentration based on the second output gas at the second gas output end and the second gas product through electrolysis.

[0014] Furthermore, in some embodiments, after obtaining the current input voltage of the first fuel cell stack, it also includes: when the current input voltage is less than or equal to the first preset voltage, the first fuel cell stack generates a third gas product based on the first output gas at the first gas output end, so that the thermochemical module performs a hydrogen release and exothermic reaction based on the third gas product to obtain a fourth gas product; and the power supply component is used to power the second fuel cell stack, so that the second fuel cell stack generates hydrogen meeting the preset concentration or a synthesis gas of a preset concentration based on the electrolysis of the second output gas and the fourth gas product.

[0015] Further, in some embodiments, after the first fuel cell stack generates the first gas product based on the first output gas at the first gas output end, it also includes: determining a target operating temperature of the thermochemical module based on the first gas product; and adjusting a current temperature of the thermochemical module based on the target operating temperature.

[0016] Furthermore, in some embodiments, the method for stable hydrogen production by a solid oxide electrolysis cell under a fluctuating power supply further includes: determining whether the first fuel cell stack is in a fault state; if the first fuel cell stack is in the fault state, maintaining the first gas output end to input the first output gas to the first fuel cell stack.

[0017] According to the stable hydrogen production method of solid oxide electrolysis cell under fluctuating power supply provided by the embodiment of the present invention, by applying fluctuating power supply to the first electrolysis stack, the thermochemical module adaptively realizes the storage and release of hydrogen / heat, realizes the regulation of the temperature and product gas of the first electrolysis stack, and then realizes the continuous production of high-purity hydrogen through the second electrolysis stack working under stable power supply. The problem of insufficient thermal management and gas component balance management of the system under fluctuating power supply conditions is solved, the system operation efficiency is improved, and the complexity of system construction is reduced.

[0018] Therefore, the stable hydrogen production device of the solid oxide electrolytic cell under the fluctuating power supply of the embodiment of the present invention has the following beneficial effects:

[0019] (1) The thermochemical module can adjust the heat and temperature of the electrolytic stack. The heat absorption and release characteristics of electrolysis under fluctuating power supply are compatible with the heat storage and release characteristics of the thermochemical reaction. The fuel electrode product gas of the electrolytic stack can be used as a heat carrier to connect the electrolytic stack and the thermochemical module, thereby achieving better heat exchange between the modules.

[0020] (2) The thermochemical module can adjust the composition of the electrolysis stack fuel electrode product gas. The H 2 Changes in concentration and Me / MeO x Thermochemical hydrogen storage and release reactions are compatible: different proportions of H at constant temperature 2 / H 2 O and Me / MeO x H in the product gas after the reaction 2 The concentration is constant, so the thermochemical module can maintain the product gas H under fluctuating power supply. 2 The concentration is constant.

[0021] (3) Me / MeO at different temperatures x With H 2 / H 2 O reaction product H 2 The concentrations are different, so the temperature of the thermochemical module is controlled within a certain temperature range to achieve the balance of H in the component product gas. 2 Concentration adjustment to meet different H 2 Concentration requirements.

[0022] (4) The equilibrium component product gas of the thermochemical module is mixed with the constant flow water vapor of gas path 2 (i.e., the second gas output end) as the reactant gas of electrolytic stack 2 (i.e., the second electrolytic stack). The gas composition is stable, H 2 The concentration can be conveniently adjusted by controlling a constant flow of water vapor, which helps prevent oxidation of the fuel electrode of the electrolytic stack 2 and facilitates the preparation of high-purity hydrogen at a large flow rate under stable power supply conditions.

[0023] (5) The hydrogen storage characteristics of the thermochemical module can play a role in buffering and protecting the electrolytic hydrogen production. For example, when the electrolytic stack 1 (i.e., the first electrolytic stack) suddenly stops working, a constant flow of water vapor continues to be introduced into the gas path 1 (i.e., the first gas output end). The thermochemical module can continue to release hydrogen for a certain period of time without affecting the operation of the electrolytic stack 2, thereby effectively protecting the efficient and stable operation of the electrolytic stack 2.

[0024] (6) The heat storage characteristics of the thermochemical module can play a role in thermal buffer protection. For example, when the electrolytic stack 1 suddenly stops working, a constant flow of water vapor continues to be introduced into the gas path 1. Within a certain period of time, the thermochemical module reacts 1 to release heat, thereby slowing down the rapid drop in the temperature of the electrolytic stack 1.

[0025] (7) Gas line 2 can also be fed with CO 2 , achieving CO in electrolysis stack 2 2 / H 2 O co-electrolysis to produce synthesis gas, reaction gas CO 2 / H 2 O / H 2 The component ratio can be conveniently adjusted by the temperature of the thermochemical module and the gas flow rate of gas path 2 to achieve different ratios of CO / H 2 Production of synthesis gas.

[0026] (8) The thermochemical module and each gas path can achieve a compact design, which will effectively simplify the auxiliary thermal management and gas balance management of the overall system and contribute to low-cost and efficient SOEC system integration.

[0027] (9) The electrolytic stack 2 can also be replaced with a solid oxide fuel cell (SOFC) power generation device. The fuel gas (methane, methanol, coal gas, etc.) is introduced into the gas path 2 and mixed with the product gas of the thermochemical module equilibrium component, which is used as the constant component fuel of the SOFC to generate electricity. This can achieve coordinated, efficient and stable power generation of fluctuating renewable energy and high energy density fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0029] Figure 1 A block diagram of a stable hydrogen production device of a solid oxide electrolytic cell under a fluctuating power supply provided in accordance with an embodiment of the present invention;

[0030] Figure 2 A graph showing heat absorption and release characteristics of a solid oxide electrolytic stack under different currents under actual working conditions according to a specific embodiment of the present invention;

[0031] Figure 3A schematic diagram of the structure of a stable hydrogen production device of a solid oxide electrolytic cell under a fluctuating power supply according to a specific embodiment of the present invention;

[0032] Figure 4 It is a schematic structural diagram of a device for stably producing synthesis gas under a fluctuating power supply according to a specific embodiment of the present invention;

[0033] Figure 5 According to a specific embodiment of the present invention, Fe / FeO x Hydrogen-water vapor equilibrium concentration distribution diagram of the material at different temperatures;

[0034] Figure 6 The present invention is a flow chart of a method for stable hydrogen production by a solid oxide electrolysis cell under a fluctuating power supply provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0036] The following describes the stable hydrogen production device and method of a solid oxide electrolytic cell under a fluctuating power supply of an embodiment of the present invention with reference to the accompanying drawings. In response to the problems mentioned in the above background technology, the present invention provides a stable hydrogen production device of a solid oxide electrolytic cell under a fluctuating power supply. By applying a fluctuating power supply to the first electrolytic stack, the thermochemical module adaptively realizes the storage and release of hydrogen / heat, realizes the regulation of the temperature and product gas of the first electrolytic stack, and then realizes the continuous production of high-purity hydrogen through the second electrolytic stack working under a stable power supply. The problem of insufficient thermal management and gas component balance management of the system under fluctuating power supply conditions is solved, the system operation efficiency is improved, and the complexity of system construction is reduced.

[0037] Specifically, Figure 1 A block diagram of a device for stable hydrogen production by a solid oxide electrolysis cell under a fluctuating power supply provided in accordance with an embodiment of the present invention.

[0038] like Figure 1 As shown, the solid oxide electrolysis cell stable hydrogen production device 10 using a fluctuating power supply includes: a fluctuating power supply 100, a first battery stack 200, a thermochemical module 300 and a second battery stack 400.

[0039] Among them, the fuel electrode air inlet of the first fuel cell stack 200 is connected to the first gas output end, the power supply end of the first fuel cell stack 200 is connected to the fluctuating power supply 100, and the fuel electrode outlet of the first fuel cell stack 200 is connected to the inlet of the thermochemical module 300. When the current input voltage of the first fuel cell stack 200 is greater than the first preset voltage, the first fuel cell stack 200 generates a first gas product based on the first output gas at the first gas output end; the thermochemical module 300 performs a hydrogen absorption and endothermic reaction based on the first gas product to obtain a second gas product; the fuel electrode air inlet of the second fuel cell stack 400 is respectively connected to the outlet and the second gas output end of the thermochemical module 300, and the second fuel cell stack 400 generates hydrogen meeting the preset concentration by electrolysis of the second output gas and the second gas product based on the second gas output end.

[0040] In some embodiments, the material in the thermochemical module 300 is a metal material and / or a metal oxide material.

[0041] The embodiment of the present invention adopts iron / iron oxide (Fe / FeO x ) is stored in the thermochemical module 300 as a gas-heat management medium, wherein Fe / FeO x The ratio of the two can be any ratio, for example, the initial molar ratio is 1:1.

[0042] Furthermore, the thermochemical module 300 operates at 700° C., wherein the hydrogen release exothermic reaction (i.e., reaction 1) of the embodiment of the present invention is: Fe+H 2 O=FeO+H 2 △H=-16.705kJ / mol or 3FeO+H 2 O=Fe 3 O 4 +H 2 △H=-10.86kJ / mol. The hydrogen absorption endothermic reaction (i.e. reaction 2) is FeO+H 2 =Fe+H 2 O△H=16.705kJ / mol or Fe 3 O 4 +H 2 =3FeO+H 2 O△H=10.86kJ / mol.

[0043] It should be noted that under actual operating conditions, the endothermic and exothermic characteristics of the electrolytic stack under different currents should be considered. Figure 2 The figure is a graph showing the heat absorption and release characteristics of a solid oxide electrolytic stack under different currents under actual working conditions according to a specific embodiment of the present invention.

[0044] like Figure 2As shown, the thermoneutral voltage of the electrolytic stack of the embodiment of the present invention is 58.5V, the corresponding current is 88A, and the electrolysis power is 5.15kW. The electrolysis process is controlled by the relationship between the electrolysis voltage and the thermoneutral voltage.

[0045] Furthermore, in some embodiments, the second output gas is water vapor with a preset flow rate or CO with a preset concentration. 2 .

[0046] As a possible implementation method, the first output gas at the first gas output end of the embodiment of the present invention is 10% H 2 The second output gas at the second gas output end is pure water vapor or CO with a preset concentration. 2 .

[0047] Further, Figure 3 This is a schematic structural diagram of a stable hydrogen production device of a solid oxide electrolytic cell under a fluctuating power supply according to a specific embodiment of the present invention. Figure 4 It is a schematic structural diagram of a stable synthesis gas production device under fluctuating power supply according to a specific embodiment of the present invention.

[0048] Specifically, in some embodiments, when the current input voltage is greater than the first preset voltage, that is, the electrolysis voltage of the first electrolysis stack 200 is greater than the thermoneutral electrolysis voltage, the H 2 As the concentration increases, H 2 The concentration of O decreases, and the first electrolytic stack 200 is in a heat release state, which increases the operating temperature. At this time, the high concentration of H 2 It can undergo an endothermic reduction reaction (i.e., reaction 2) with FeO stored in the thermochemical module 300 to generate Fe and H 2 O, not only reduces the H 2 The concentration increases H 2 O concentration, and the endothermic reaction can be used to cool the H entering the first electrolysis stack 200. 2 / H 2 O raw material, lowering the operating temperature of the first electrolytic stack 200, so that the first electrolytic stack 200 returns to a balanced operating temperature and gas composition. Subsequently, the balanced component second gas product of the thermochemical module 300 is mixed with the constant flow water vapor at the second gas output end, enters the second electrolytic stack 400, and is further electrolyzed into high-purity H by a stable power supply. 2 .

[0049] Furthermore, in some embodiments, the second gas at the second gas output end may be CO with a preset concentration. 2 , through the first electric stack 200 and the thermochemical module 300, the second electrolytic stack 400 electrolyzes the obtained mixed gas into CO / H2 Mixed gas.

[0050] Furthermore, in some embodiments, the first fuel cell stack 200 generates a third gas product based on the first output gas at the first gas output end when the current input voltage is less than or equal to the first preset voltage; the thermochemical module 300 performs a hydrogen release and exothermic reaction based on the third gas product to obtain a fourth gas product; and the second fuel cell stack 400 generates hydrogen meeting a preset concentration or a synthetic gas of a preset concentration based on electrolysis of the second output gas and the fourth gas product.

[0051] Specifically, in some embodiments, when the current input voltage is less than the first preset voltage, that is, when the electrolysis voltage of the first electrolysis stack 200 is less than the thermoneutral electrolysis voltage, H 2 The concentration decreased, H 2 As the concentration of O increases, the first electrolytic stack 200 is in an endothermic state, which reduces the operating temperature. 2 O can react with Fe stored in the thermochemical module 300 in an exothermic oxidation reaction (reaction 1) to generate H 2 and FeO, which not only increases the H 2 concentration, reducing H 2 O concentration, and the exothermic reaction can be used to heat the H entering the first electrolysis stack 200. 2 / H 2 O mixed gas, raising the operating temperature of the first electrolytic stack 200, so that the first electrolytic stack 200 returns to a balanced operating temperature and gas composition. Subsequently, the fourth product gas of the balanced component of the thermochemical module 300 and the constant flow water vapor at the second gas output end enter the second electrolytic stack 400, and are further electrolyzed into high-purity H by a stable power supply. 2 .

[0052] Furthermore, in some embodiments, the second gas at the second gas output end may also be CO with a preset concentration. 2 , through the first electric stack 200 and the thermochemical module 300, the second electrolytic stack 400 electrolyzes the obtained mixed gas into CO / H 2 Mixed gas.

[0053] It should be noted that the Fe / FeO x The hydrogen-water vapor equilibrium concentration distribution of the material at different temperatures is different. Figure 5 According to a specific embodiment of the present invention, Fe / FeO x Hydrogen-water vapor equilibrium concentration distribution diagram of the material at different temperatures.

[0054] like Figure 5 As shown, Fe / FeO at 700℃x The corresponding H 2 The equilibrium concentration is about 70%, that is, when the hydrogen concentration is lower than 70%, a hydrogen release exothermic reaction (i.e., reaction 1) occurs; when the hydrogen concentration is higher than 70%, a hydrogen absorption endothermic reaction (i.e., reaction 2) occurs. It should be noted that when the temperature of the thermochemical module 300 is lower than 550°C, only Fe-Fe 3 O 4 The reactions convert into each other and no FeO is produced.

[0055] Furthermore, in some embodiments, the apparatus for stable hydrogen production by a solid oxide electrolysis cell under a fluctuating power supply further includes: a power supply component connected to the second battery stack 400, and configured to provide voltage when the second battery stack 400 performs electrolysis.

[0056] Among them, the power supply component should use a stable power supply to continuously supply power to the second fuel cell stack 400 during electrolysis to ensure the purpose of stable hydrogen production.

[0057] Further, in some embodiments, the temperature of the thermochemical module is determined by the first gas product or the third gas product.

[0058] Specifically, Me / MeO at different temperatures x With H 2 / H 2 O reaction product H 2 The concentrations are different, so the temperature of the thermochemical module is controlled within a certain temperature range to achieve the balance of H in the component product gas. 2 Concentration adjustment to meet different H 2 Concentration requirements.

[0059] According to the stable hydrogen production device of solid oxide electrolysis cell under fluctuating power supply provided by the embodiment of the present invention, by applying fluctuating power supply to the first electrolysis stack, the thermochemical module adaptively realizes the storage and release of hydrogen / heat, realizes the regulation of the temperature and product gas of the first electrolysis stack, and then realizes the continuous production of high-purity hydrogen through the second electrolysis stack working under stable power supply. The problem of insufficient thermal management and gas component balance management of the system under fluctuating power supply conditions is solved, the system operation efficiency is improved, and the complexity of system construction is reduced.

[0060] Next, the method for stable hydrogen production by a solid oxide electrolytic cell under a fluctuating power supply proposed in accordance with an embodiment of the present invention will be described with reference to the accompanying drawings.

[0061] Figure 6 The present invention is a flow chart of a method for stable hydrogen production by a solid oxide electrolysis cell under a fluctuating power supply provided in accordance with an embodiment of the present invention.

[0062] like Figure 6 As shown, the method for stable hydrogen production by solid oxide electrolysis cell under fluctuating power supply comprises the following steps:

[0063] In step S601, the current input voltage of the first battery stack is obtained;

[0064] In step S602, when the current input voltage is greater than the first preset voltage, the first fuel cell generates a first gas product based on the first output gas at the first gas output end, so that the thermochemical module performs a hydrogen absorption and endothermic reaction based on the first gas product to obtain a second gas product;

[0065] In step S603, the power supply assembly is used to supply power to the second fuel cell stack, so that the second fuel cell stack generates hydrogen meeting a preset concentration based on electrolysis of the second output gas and the second gas product at the second gas output end.

[0066] Furthermore, in some embodiments, after obtaining the current input voltage of the first fuel cell stack, it also includes: when the current input voltage is less than or equal to the first preset voltage, the first fuel cell stack generates a third gas product based on the first output gas at the first gas output end, so that the thermochemical module performs a hydrogen release and exothermic reaction based on the third gas product to obtain a fourth gas product; and the second fuel cell stack is powered by a power supply component, so that the second fuel cell stack generates hydrogen meeting a preset concentration or a synthesis gas of a preset concentration based on the electrolysis of the second output gas and the fourth gas product.

[0067] Furthermore, in some embodiments, after the first fuel cell stack generates a first gas product based on the first output gas at the first gas output end, it also includes: determining a target operating temperature of the thermochemical module based on the first gas product; and adjusting a current temperature of the thermochemical module based on the target operating temperature.

[0068] Furthermore, in some embodiments, the method for stable hydrogen production by a solid oxide electrolysis cell under a fluctuating power supply further includes: determining whether the first fuel cell stack is in a fault state; if the first fuel cell stack is in a fault state, maintaining the first gas output end to input the first output gas to the first fuel cell stack.

[0069] It should be noted that the aforementioned explanation of the embodiment of the apparatus for stable hydrogen production by a solid oxide electrolysis cell under a fluctuating power supply is also applicable to the method for stable hydrogen production by a solid oxide electrolysis cell under a fluctuating power supply of this embodiment, and will not be repeated here.

[0070] According to the stable hydrogen production method of solid oxide electrolysis cell under fluctuating power supply provided by the embodiment of the present invention, by applying fluctuating power supply to the first electrolysis stack, the thermochemical module adaptively realizes the storage and release of hydrogen / heat, realizes the regulation of the temperature and product gas of the first electrolysis stack, and then realizes the continuous production of high-purity hydrogen through the second electrolysis stack working under stable power supply. The problem of insufficient thermal management and gas component balance management of the system under fluctuating power supply conditions is solved, the system operation efficiency is improved, and the complexity of system construction is reduced.

[0071] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0072] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0073] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0074] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0075] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

Claims

1. A stable hydrogen production device for a solid oxide electrolytic cell under fluctuating power supply, characterized in that: include: A fluctuating power supply, a first battery stack, a thermochemical module and a second battery stack, wherein: The fuel electrode gas inlet of the first fuel cell stack is connected to the first gas output end, the power supply end of the first fuel cell stack is connected to the fluctuating power supply, the fuel electrode outlet of the first fuel cell stack is connected to the inlet of the thermochemical module, and the first fuel cell stack generates a first gas product based on the first output gas of the first gas output end when the current input voltage is greater than the first preset voltage; The thermochemical module performs a hydrogen absorption and endothermic reaction based on the first gas product to obtain a second gas product; The fuel electrode air inlet of the second fuel cell stack is respectively connected to the outlet of the thermochemical module and the second gas output end, and the second fuel cell stack electrolyzes the second output gas from the second gas output end and the second gas product to generate hydrogen meeting a preset concentration.

2. The stable hydrogen production device of solid oxide electrolysis cell under fluctuating power supply according to claim 1 is characterized in that: When the current input voltage of the first fuel cell stack is less than or equal to the first preset voltage, the first fuel cell stack generates a third gas product based on the first output gas of the first gas output end; The thermochemical module performs a hydrogen release and exothermic reaction based on the third gas product to obtain a fourth gas product; The second fuel cell stack generates hydrogen meeting the preset concentration or synthesis gas meeting the preset concentration by electrolysis based on the second output gas and the fourth gas product.

3. The stable hydrogen production device of solid oxide electrolysis cell under fluctuating power supply according to claim 1 or 2, characterized in that: Also includes: A power supply component is connected to the second battery stack and is used to provide voltage when the second battery stack performs electrolysis.

4. The stable hydrogen production device of solid oxide electrolysis cell under fluctuating power supply according to claim 1 is characterized in that: The temperature of the thermochemical module is determined by the first gas product or the third gas product.

5. The stable hydrogen production device of solid oxide electrolysis cell under fluctuating power supply according to claim 1 is characterized in that: The material in the thermochemical module is a metal material and / or a metal oxide material.

6. The stable hydrogen production device of solid oxide electrolysis cell under fluctuating power supply according to claim 1, characterized in that: The second output gas is water vapor of a preset flow rate or CO2 of a preset concentration.

7. A method for stable hydrogen production by solid oxide electrolysis cell under fluctuating power supply, characterized in that: A stable hydrogen production device for a solid oxide electrolytic cell under a fluctuating power supply according to any one of claims 1 to 6, wherein the method comprises the following steps: Obtaining the current input voltage of the first battery stack; When the current input voltage is greater than the first preset voltage, the first fuel cell generates a first gas product based on the first output gas at the first gas output end, so that the thermochemical module performs a hydrogen absorption and endothermic reaction based on the first gas product to obtain a second gas product; The second fuel cell stack is powered by a power supply component, so that the second fuel cell stack generates hydrogen meeting the preset concentration based on electrolysis of the second output gas from the second gas output end and the second gas product.

8. The method according to claim 7, characterized in that After obtaining the current input voltage of the first battery stack, the method further includes: When the current input voltage is less than or equal to the first preset voltage, the first fuel cell generates a third gas product based on the first output gas at the first gas output end, so that the thermochemical module performs a hydrogen release and exothermic reaction based on the third gas product to obtain a fourth gas product; The power supply component is used to supply power to the second fuel cell stack, so that the second fuel cell stack generates hydrogen meeting the preset concentration or synthesis gas meeting the preset concentration based on electrolysis of the second output gas and the fourth gas product.

9. The method according to claim 7, characterized in that: After the first fuel cell stack generates the first gas product based on the first output gas at the first gas output end, the method further includes: determining a target operating temperature of the thermochemical module based on the first gas product; Based on the target operating temperature, the current temperature of the thermochemical module is adjusted.

10. The method according to claim 7, characterized in that Also includes: Determining whether the first fuel cell stack is in a fault state; If the first fuel cell stack is in the fault state, the first gas output end is maintained to input the first output gas to the first fuel cell stack.

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