SOEC system architecture method for improving system efficiency

Abstract

An SOEC system architecture method for improving system efficiency comprises an air device, a liquid water device, a hydrogen storage / utilization device, an auxiliary starting device and an electric energy supply device. The air supply device receives an atmospheric air source, the opening and closing or opening adjustment is performed through an electromagnetic valve I by referring to the system operation oxygen concentration, the discharge air temperature, the electric pile voltage and the like, the incoming air of the air source and the incoming air of the electric pile discharge air are converged at the upstream of the filter and flow into the filter, and the drum press provides medium flowing power and electric energy power supply for the system; electric energy is converted into heat energy and pressure energy of incoming flow air, and part of the electric energy comes from a circuit; a water pump of a liquid water supply device provides medium flowing power for the system, three heat exchangers and a condenser are arranged in a combined mode, cooling of liquid water is used for absorbing heat of a hydrogen discharging preheater, and meanwhile the liquid water in hydrogen discharging is condensed and recycled. The hydrogen storage / utilization device is used for multi-stage compression and intermediate cooling, and the produced hydrogen is stored during energy storage peak regulation; auxiliary start-up and power supply are used for powering the edge device for system start-up. The method has the advantages of improving SOEC system efficiency, reducing product cost, improving benefits and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature solid oxide electrolyzed water technology, and particularly relates to a method for the SOEC system architecture to improve system efficiency. Background Art

[0002] Solid oxide electrolyzed water cell (SOEC) systems have received more attention than before because they can make full use of waste heat and the carrier carrying waste heat (such as water vapor) during the hydrogen production process, reduce electricity consumption, and improve energy utilization efficiency.

[0003] The SOEC system architecture is the core of building an SOEC system, guiding the operation of the SOEC system, and determining the layout and operating parameters of system components. This application has conducted a full investigation of the prior art and existing patents of the SOEC system architecture, and investigated the common means of the SOEC system architecture. The SOEC system of Patent CN114855188A mainly includes an air supply branch, a fuel supply branch, and other auxiliary branches. The air supply branch includes an air supply system, an air heat exchanger, and an air electric heater. The fuel supply branch includes a fuel supply system, a fuel heat exchanger, and a fuel electric heater. For the discharged hydrogen, a heat exchanger is used to recover heat, and then it is directly discharged to the hydrogen storage device through a condenser. For the discharged air, a heat exchanger is used to recover heat, and then the gas is discarded. Patent CN115807232A supplements a waste heat recovery unit compared with the former, which can improve the system efficiency to a certain extent. The essence of this technical point of the waste heat recovery unit is to improve the utilization of "industrial waste heat", and there is a lack of technical description and innovation points for the reuse of the heat of the hydrogen and air discharged from the SOEC itself, such as the heat utilization sequence and the medium flow direction. It is not an ideal and feasible solution to simply and comprehensively introduce them into the waste heat recovery unit.

[0004] To solve the above problems, some people have successively disclosed: Patent CN115172800A, which introduces a burner to ignite hydrogen, thereby utilizing the conversion of chemical energy into thermal energy. It will perform frequent ignition and extinguishing operations. Although there is a flame in the system, it increases the unreliability and risk factors of the system; there are also some related utility model patents, such as Patent CN213340447U. In the system architecture, there is no heat recovery unit for the discharged air, and it is directly discharged into the atmosphere. There is also no waste heat and residual heat utilization unit for the incoming liquid water, and it directly uses electrical energy and chemical energy for heating, which will reduce the system efficiency. The SOEC system architecture also lacks the arrangement of components, especially those related to heat, and is not sufficient to fully utilize the high-efficiency characteristics of SOEC; Patent CN217485503U sets up a liquid water / steam supply subsystem for the SOEC system architecture. No components related to heat utilization are set in this subsystem, and only an electric evaporator is arranged. Although the hydrogen production method is feasible, it is not friendly to energy utilization efficiency, and there is also a problem of insufficient heat utilization of the hydrogen and discharged air from SOEC.

[0005] In short, the prior art cannot fully utilize the heat / energy mapping contained in the SOEC exhaust gas onto the SOEC system architecture. The focus is on the unreasonable arrangement of heat exchange components, the poor selection of system component types, and the complexity of components, resulting in the non-utilization of energy other than thermal energy.

[0006] Therefore, it is of great significance to develop a method for the SOEC system architecture to improve system efficiency. Summary of the Invention

[0007] The task of the present invention is to overcome the deficiencies of the prior art and propose a method for the SOEC system architecture to improve system efficiency, which can not only improve the SOEC system efficiency, but also reduce product costs and increase benefits.

[0008] A SOEC system architecture method for improving system efficiency, aiming at problems such as complex heat exchange components and unreasonable layout, poor selection of system component types, and unutilized energy other than thermal energy. It includes an air supply device, a liquid water supply device, a hydrogen storage / utilization device, an auxiliary startup system, and an electric energy supply device; the air supply device is supplied with atmospheric air source 109 through solenoid valve 101. Solenoid valve 101 opens, closes or adjusts the opening according to strategy indicators such as the oxygen concentration during system operation, the temperature of the discharged air, and the stack voltage, thus affecting the air supply volume of air source 109. The incoming air of air source 109 and the incoming air of the stack discharged air converge upstream of filter 102 and flow into filter 102. Blower or compressor 103 provides power for the medium flow in the system and is powered by the electric energy supply system, converting electric energy into the thermal energy and pressure energy of the incoming air. Part of the electric energy comes from circuit S7 and part comes from circuit S5. Utilizing these energies can improve the overall efficiency of the system; the liquid water supply device, water pump 203 provides power for the medium flow in the system. Heat exchanger three B3 heat exchanger and condenser are arranged in one, making full use of the cooling effect of liquid water to absorb heat from the hydrogen discharge preheater, and at the same time condensing and recovering the liquid water in the hydrogen discharge. The hydrogen storage / utilization device is multi-stage compression and intercooling, and is used to store the produced hydrogen when applied to chemical production and energy storage peak shaving. The auxiliary startup device and the electric energy supply device are used for system startup as edge devices respectively.

[0009] The innovation points of the present invention are as follows:

[0010] I. The SOEC system architecture proposes an air medium recovery scheme in the industry. Effect: Saving heat utilization. This scheme returns the air discharged by SOEC back to the stack, maximizing the use of the heat carried by the medium. The air discharged by SOEC flows through a three-way valve, part is discharged to the atmosphere, and part converges with fresh air. The relevant ratio is not restricted and is flexibly adjusted according to the system strategy. It not only ensures the purging requirement of oxygen during the operation of the SOEC stack, but also avoids the waste of stack heat with the discharged atmosphere. And this scheme improves the concentration of the by-product oxygen of SOEC, expands the application occasions and economic benefits of the SOEC system, and improves the system efficiency.

[0011] II. The SOEC system architecture proposes a turbine introduction scheme in the industry. Effect: In addition to heat recovery, this scheme additionally recovers pressure energy, innovating the form of energy reuse of the air discharged by SOEC. The air discharged by SOEC generates electric energy or directly drives the compressor / blower in the system to work after flowing through the turbine, reducing the use of external electric energy. When SOEC electrolyzes water as the upstream link in the production of chemical products such as green methanol, green methane, and green ammonia, the working pressure of the gaseous medium of SOEC reaches about 5 bar(g), and there is economic efficiency in recovering pressure energy.

[0012] III. The SOEC system architecture combines the heat exchanger and the condenser into one, and arranges the hydrogen discharge preheater upstream of the exhaust preheater. Effect: This solution fully utilizes the cooling effect of liquid water to absorb heat from the hydrogen discharge preheater. At the same time, it condenses and recovers the pure water in the hydrogen discharge. It streamlines the system components, makes the selection of component types more reasonable, and improves the system efficiency.

[0013] IV. The SOEC system architecture proposes a "1 + 3" heat exchanger arrangement scheme in terms of the heat exchanger arrangement position and the number of heat exchangers. Effect: It makes up for the problem that the heat dissipation capacity of hydrogen is insufficient compared to the heat absorption capacity of liquid water / steam, and further expands the utilization of the heat dissipation capacity of air. The number and position arrangement of the heat exchange components are more reasonable, improving the system efficiency.

[0014] V. The SOEC system architecture invents a multi-stage compression and intermediate cooling scheme for hydrogen storage, and cools the intermediate heat exchanger through the incoming air path and the water path respectively. Effect: It not only saves the energy consumption of the compressor but also supplements the heat demand of the SOEC system.

[0015] Compared with the prior art, the present invention has the following advantages or effects:

[0016] Because the SOEC system architecture is no longer limited to only the utilization of heat in the air medium recovery, but expands the form of energy reuse, such as pressure energy, heat utilization is saved; at the same time, since the concentration of the by-product oxygen of the SOEC is increased, the application scenarios and economic benefits of the SOEC system are expanded; in addition, due to the proposed "1 + 3" heat exchanger arrangement scheme, the problem that the heat dissipation capacity of hydrogen is insufficient compared to the heat absorption capacity of liquid water / steam is made up for, and the expansion of the utilization of the heat dissipation capacity of air is further exerted; in addition, because the heat exchanger and the condenser are combined into one and the hydrogen discharge preheater is arranged upstream of the exhaust preheater, the cooling effect of liquid water can be fully utilized to absorb heat from the hydrogen discharge preheater and at the same time condense and recover the liquid water in the hydrogen discharge.

[0017] In summary, the present invention utilizes the energy outside the thermal energy contained in the SOEC system medium, the number and position arrangement of the heat exchange components are more reasonable, the system components are streamlined, and the selection of component types is more reasonable, which can not only improve the SOEC system efficiency but also reduce the product cost and increase the benefits.

[0018] In this application document, SOEC: the full English name is "Solid Oxide Electrolysis Cell", and the full Chinese name is "Solid Oxide Electrolysis Cell". BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a schematic diagram of a SOEC system architecture for improving system efficiency proposed according to the present invention.

[0020] Figure 2 For Figure 1 The calculation diagram of the improvement effect of the SOEC system architecture for improving system efficiency as shown.

[0021] Figure 3 For Figure 1 The schematic diagram of the SOEC system architecture and the air recovery device for improving system efficiency as shown.

[0022] Figure 4 For Figure 1 The schematic diagram of the liquid water supply system of the SOEC system architecture for improving system efficiency and the layout of the "1+3" heat exchangers as shown.

[0023] Each identification symbol in the attached drawings respectively represents:

[0024] 101. Solenoid valve 1 102. Filter 103. Blower or compressor 104. Air mass flow meter 105. Air heater 106. Turbine 107. Three-way valve 1 109. Ambient air source 201. Liquid water purification device 202. Pure water tank 203. Water pump 204. Electric evaporator 205. Steam heater 206. Three-way valve 2 207. Solenoid valve 2 208. Return pump 209. Hydrogen mass flow meter 210. Check valve 2 211. Check valve 1 212. Gas-liquid separator 213. Liquid water source 214. Ambient environment 215. Hydrogen downstream equipment 301. SOEC stack 302. Industrial alternating current 303. AC / DC converter 401. Hydrogen storage tank 402. Nitrogen source 403. Hydrogen compression device 404. First-stage compressor 405. First-stage compression intermediate heat exchanger 406. Second-stage compressor 407. Second-stage compression intermediate heat exchanger 501. Hydrogen downstream equipment A1. Heat exchanger 1 B1 Heat exchanger 4 B2. Heat exchanger 2 B3. Heat exchanger 3 S1~S7. Circuit

[0025] The present invention will be further described in detail below with reference to the attached drawings. Specific embodiments

[0026] As Figures 1-4As shown in the figure, a method for the SOEC system architecture to improve system efficiency. Aiming at problems such as complex heat exchange components and unreasonable layout, poor selection of system component types, and unutilized energy other than thermal energy, it includes an air supply device, a liquid water supply device, a hydrogen storage / utilization device, an auxiliary startup system, and an electric energy supply device; the air supply device is supplied with atmospheric air source 109 through solenoid valve 101. Solenoid valve 101 opens, closes or adjusts the opening degree according to strategy indicators such as the oxygen concentration during system operation, the temperature of the discharged air, and the stack voltage, thereby affecting the air supply volume of air source 109. The incoming air of air source 109 and the incoming air of the stack discharged air converge upstream of filter 102 and flow into filter 102. Blower or compressor 103 provides the power for the medium flow in the system and is powered by the electric energy supply system, converting electric energy into the thermal energy and pressure energy of the incoming air. Part of the electric energy comes from circuit S7 and part comes from circuit S5. Utilizing these energies can improve the overall efficiency of the system; the liquid water supply device water pump 203 provides the power for the medium flow in the system. Heat exchanger three B3 heat exchanger and condenser are arranged in one, making full use of the cooling effect of liquid water to absorb heat from the hydrogen discharge preheater, and at the same time condensing and recovering the liquid water in the hydrogen discharge. The hydrogen storage / utilization device is for multi-stage compression and intermediate cooling, and is used to store the produced hydrogen when applied to chemical production and energy storage peak regulation. The auxiliary startup device and the electric energy supply device are used for system startup as edge devices respectively.

[0027] This method can further be

[0028] An air quality flowmeter 104 is arranged downstream of the blower or compressor 103 in the air supply device, which can detect the air supply volume to the stack; before the air is supplied to the SOEC stack 301, it needs to flow through heat exchanger one A1 and air heater 105 in sequence. Heat exchanger one A1 can recover the heat of the stack discharged air; correct the temperature of the incoming air before entering the air heater 105 and the stack. The discharged air first flows through heat exchanger one A1 for primary heat exchange, and then flows through heat exchanger two B2 to fully utilize the heat of the discharged air.

[0029] It is that the discharged air of the air supply device flows through turbine 106 and three-way valve 107. Three-way valve 107 can control the recycled amount of the air discharged from the stack and the amount of air discharged to the atmosphere or oxygen utilization occasions.

[0030] The recycled amount of air in the air supply device converges with the downstream air of solenoid valve 101, which can complete the full or partial circular flow of the air in the air supply SOEC system.

[0031] The blower or compressor 103 of the air supply device provides the driving force for the medium flow of the air supply system. A turbine 106 is arranged downstream of the SOEC exhaust air, which can utilize the pressure energy of the SOEC exhaust air. The turbine 106 supplies power to the blower or compressor 103 through the circuit S5 or the turbine 106 is coaxial with the blower or compressor 103, and can directly transfer kinetic energy.

[0032] The liquid water source 213 of the liquid water supply device is tap water or industrial wastewater with a temperature d higher than the ambient temperature. First, it flows through the liquid water purification device 201 to remove particulate impurities and metal ions in the water. The pure water tank 202 has an opening communicating with the atmospheric environment 214. The outlet of the pure water tank 202 is connected to the inlet of the water pump 203, which can adjust the liquid level in the pure water tank 202.

[0033] The outlet of the water pump 203 of the liquid water supply device is connected to the low-temperature side inlet of the heat exchanger III B3. The liquid water is heated by the secondary heat exchange of the hydrogen discharged from the stack. The heat exchanger III B3 is placed upstream of the heat exchanger II B2, which can use low-temperature liquid water to cool the discharged hydrogen, and then condense the water vapor contained in the discharged hydrogen.

[0034] The hot side of the heat exchanger III B3 of the liquid water supply device flows through the hydrogen discharged from the stack, and the hot side of the heat exchanger II B2 flows through the air discharged from the stack. Both are secondary heat exchanges using the exhaust heat of the stack.

[0035] The cold-side outlet of the heat exchanger II B2 of the liquid water supply device is the heated liquid water or a liquid-vapor mixture. After being vaporized by the electric evaporator 204, it converges with the incoming hydrogen upstream of the heat exchanger IV B1. It can greatly utilize the heat of the hydrogen discharged from the stack and complete heat exchange together in the heat exchanger IV B1. The water vapor enters the steam heater 205 to adjust the temperature before entering the stack. The hydrogen discharged from the stack flows through the heat exchanger IV B1 and the heat exchanger III B3 in sequence, and enters the gas-liquid separator 212 at a lower temperature. The liquid water condensed in the heat exchanger III B3 is discharged to the pure water tank 202 through the one-way valve 211, and the recovery of the liquid water in the liquid water supply system can be completed.

[0036] The hydrogen gas discharged from the gas-liquid separator 212 of the liquid water supply device is adjusted by the three-way valve 206. Part of the hydrogen gas flows out of the liquid water supply device and is discharged to the hydrogen downstream equipment 215. The remaining hydrogen gas flows through the solenoid valve 207, and then through the reflux pump 208, the hydrogen mass flow meter 209, and the one-way valve 210, and converges with the incoming steam upstream of the heat exchanger IV B1.

[0037] The heat exchanger A1, heat exchanger B2, heat exchanger B3, and heat exchanger B1 in the "1 + 3" layout of the SOEC system architecture arrange 1 heat exchanger A1 in the air supply system and 3 heat exchangers, namely, heat exchanger B1, heat exchanger B2, and heat exchanger B3, in the liquid water supply device. Heat exchanger B3 is arranged upstream of heat exchanger B2, which can make up for the insufficient heat dissipation capacity of hydrogen relative to the heat absorption capacity of liquid water / steam and further expand the utilization of the heat dissipation capacity of air, thereby improving the efficiency of the SOEC system.

[0038] In the hydrogen storage / utilization device, the hydrogen from the three-way valve 206 enters the hydrogen compression device 403 and flows through the first-stage compressor 404, the first-stage compression intermediate heat exchanger 405, the second-stage compressor 406, and the second-stage compression intermediate heat exchanger 407 in sequence. The incoming air path and water path of the stack cool the two intermediate heat exchangers 405 and 407 respectively, which can reduce the energy consumption of the compressor and supplement the heat required by the SOEC system.

[0039] On the other hand, in the hydrogen storage / utilization device, the hydrogen storage tank 401 and the nitrogen source 402 provide the gases required by the stack during the startup process of the stack to assist in the startup of the SOEC system.

[0040] The hydrogen storage / utilization device includes a hydrogen storage tank 401, a nitrogen source 402, and a hydrogen compression device 403. The hydrogen discharged from the stack passes through the hydrogen compression device 403 to compress the hydrogen into the hydrogen storage tank 401 under a certain pressure, which can improve the hydrogen storage density.

[0041] The hydrogen storage / utilization device can be set according to the system power and hydrogen production amount, and is not limited to two-stage compression and intermediate cooling.

[0042] The power supply device includes the SOEC system stack 301, industrial alternating current 302, and an AC / DC converter 303. The industrial alternating current 302 supplies power for electrolyzing water to the SOEC stack 301 through the AC / DC converter 303, and supplies power to the blower or compressor 103, the air heater 105, the water pump 203, the electric evaporator 204, and the steam heater 205 through circuits S1 - S4, S6, and S7 respectively.

[0043] Embodiment 1

[0044] The present invention relates to a static connection relationship of an SOEC system architecture for improving system efficiency. The SOEC system architecture includes an air supply device, a liquid water supply device, a hydrogen storage device, an auxiliary startup device, and a power supply device.

[0045] SOEC system air supply device and air recovery method. The atmospheric air source 109 is supplied into the air supply system through the first solenoid valve 101. The first solenoid valve 101 opens, closes or adjusts the opening degree according to the system operation strategy indicators (such as oxygen concentration, temperature of the discharged air, stack voltage, etc.), thereby affecting the air supply volume of the air source 109. The incoming air of the air source 109 and the incoming air of the stack discharged air converge upstream of the filter 102 and further flow into the filter 102. The blower or compressor 103, as a key component of the air supply system, provides the power for the medium flow in the system. Downstream of the blower or compressor 103, an air mass flow meter 104 is arranged to detect the air supply volume of the stack. Before the air is supplied to the SOEC stack 301, it needs to flow through the first heat exchanger A1 and the air heater 105 in sequence. The first heat exchanger A1 recovers the heat of the stack discharged air, which is crucial for improving the system efficiency in the SOEC system. The air heater 105 corrects the temperature of the incoming air before entering the stack, which is also crucial for ensuring the stable operation of the system and the stack in the SOEC system, and at the same time affects the electrolytic water efficiency of the stack and further affects the system efficiency. The stack discharged air first flows through the first heat exchanger A1 to conduct a primary heat exchange with the incoming air to the stack, and then flows through the second heat exchanger B2. Such an arrangement is reasonable because the heat capacity of the stack discharged air exceeds that of the incoming air to the stack, and the first heat exchanger A1 is not sufficient to fully utilize the heat of the discharged air. Further, the discharged air flows through the turbine 106, and then passes through the first three-way valve 107. The first three-way valve 107 controls the air recycling volume of the stack discharged air and the air volume discharged to the atmosphere or the oxygen utilization occasion. The air recycling volume converges with the air downstream of the first solenoid valve 101. In this way, all or part of the air in the air supply system is circulated.

[0046] A turbine 106 is arranged downstream of the SOEC discharged air, so as to realize the utilization of the pressure energy of the SOEC discharged air. The turbine 106 supplies power to the component 103 through the circuit S5, or the turbine 106 and the component 103 are coaxially designed to realize kinetic energy transfer.

[0047] SOEC system liquid water supply system and "1 + 3" heat exchanger layout scheme: One heat exchanger A1 is arranged in the air supply system, and the remaining three heat exchangers B1 to B3 are arranged in the liquid water supply system. It is required that heat exchanger three B3 is arranged upstream of heat exchanger two B2. The liquid water source 213 can come from urban tap water or industrial wastewater with a certain temperature. First, it flows through the liquid water purification device 201 to remove particulate impurities and metal ions in the tap water and wastewater. The pure water tank 202 of the liquid water supply system must be opened and connected to the atmosphere 214 to adjust the liquid level in the tank. The outlet of the pure water tank 202 is connected to the inlet of the water pump 203. The water pump 203, as a key component of the liquid water supply system, provides the power for the medium flow in the system. The water pump outlet is connected to the low-temperature side inlet of heat exchanger three B3, and the liquid water is heated through the secondary heat exchange of the hydrogen discharged by the stack, making full use of the heat of the discharged hydrogen. The hot side of heat exchanger three B3 flows through the hydrogen discharged by the stack, and the hot side of heat exchanger two B2 flows through the air discharged by the stack, and both are secondary heat exchanges of exhaust gas, making full use of the exhaust heat of the stack. The cold side outlet of heat exchanger two B2 is the heated liquid water or liquid-vapor mixture, which further flows through the electric evaporator 204 to complete the vaporization of all liquid water. Subsequently, the vaporized steam converges with the incoming hydrogen upstream of heat exchanger four B1 and jointly exchanges heat with the hydrogen discharged by the stack in the heat exchanger four B1, making great use of the heat of the hydrogen discharged by the stack. The water vapor further enters the steam heater 205 to complete the temperature adjustment before entering the stack. The hydrogen discharged by the stack flows through heat exchanger four B1 and heat exchanger three B3 in sequence, enters the gas-water separator 212 at a lower temperature, and discharges the liquid water condensed in heat exchanger three B3 to the pure water tank 202 through the one-way valve one 211, completing the recovery of liquid water in the liquid water supply system. The hydrogen discharged from the gas-water separator 212 flows through the three-way valve two 206. Through the adjustment of the three-way valve two, part of the hydrogen flows out of the liquid water supply system and is discharged to the equipment 215 further downstream, and the remaining hydrogen flows through the solenoid valve two 207, flows through the reflux pump 208, the hydrogen mass flowmeter 209, and the one-way valve two 210 in sequence, and converges with the incoming steam upstream of heat exchanger four B1.

[0048] The high-efficiency SOEC system architecture includes an air supply device, a liquid water supply device, an auxiliary start device, a hydrogen storage device, and an electric energy supply device. The electric energy supply system mainly includes an SOEC stack 301, industrial alternating current 302, and an AC / DC converter 303. The industrial alternating current 302 supplies the electric energy required for electrolyzing water to the SOEC stack 301 through the AC / DC converter 303. Relative to the power consumption requirements of the SOEC stack, the industrial alternating current 302 supplies electric energy to the blower or compressor 103, the air heater 105, the water pump 203, the electric evaporator 204, and the steam heater 205 through the circuits S1 - S4, S6, S7 to generate heat energy and pressure energy.

[0049] The hydrogen storage system and the auxiliary start-up system mainly include a hydrogen storage tank 401, a nitrogen source 402, and a hydrogen compression device 403. The hydrogen discharged from the stack passes through the hydrogen compression device 403, and the hydrogen is compressed into the hydrogen storage tank 401 under a certain large pressure to improve the hydrogen storage density. The hydrogen from the three-way valve two 206 enters the compression device 403 and flows through the first-stage compressor, the first-stage compression intermediate heat exchanger, the second-stage compressor, and the second-stage compression intermediate heat exchanger in sequence. The incoming stack air path and water path cool the two intermediate heat exchangers respectively. In this way, both the energy consumption of the compressor is saved and the heat demand of the SOEC system is supplemented. According to the system power and hydrogen production amount, the multi-stage compression and intermediate cooling scheme is not limited to two stages, and the present invention does not limit the specific number of stages. On the other hand, it is a commonly used method in the industry to provide the gases required by the stack during the start-up process of the stack by the hydrogen storage tank 401 and the nitrogen source 402 to assist the start-up of the SOEC system, which will not be elaborated here.

[0050] Embodiment 2

[0051] In the dynamic process of the SOEC system architecture for improving the system efficiency of the present invention, the hydrogen produced by the system is supplied to the downstream device 501 for use. Specifically, the hydrogen downstream device 501 includes, but is not limited to, the devices involved in the production of chemical products such as green methanol, green methane, and green ammonia. In this usage scenario, taking the foreign enterprise Sunfire as an example, the operating parameters for the SOEC system to produce hydrogen are shown in the following table. This embodiment applies these operating parameters to the present invention.

[0052] Table of relevant parameters for the foreign Sunfire enterprise's SOEC system to produce hydrogen

[0053]

[0054] The atmospheric air source 109 is supplied into the air supply system through the first solenoid valve 101. The first solenoid valve 101 opens, closes or adjusts the opening degree with reference to the system operation strategy indicators (such as oxygen concentration, temperature of the discharged air, stack voltage, etc.), thereby affecting the air supply volume of the above-mentioned air source 109. The incoming air of the air source 109 and the incoming air of the stack discharged air converge upstream of the filter 102 and further flow into the filter 102 described above. The compressor 103, as a key component of the air supply system, provides the power for the medium flow in the system. The air quality flowmeter 104 is arranged downstream of the compressor 103 to detect the air supply volume of the stack. Before the air is supplied to the SOEC stack 301, it needs to further flow through the first heat exchanger A1 and the air heater 105 in sequence. The first heat exchanger A1 recovers the heat of the stack discharged air, which is crucial for improving the system efficiency in the SOEC system. The air heater 105 corrects the temperature of the incoming air before entering the stack, which is crucial for ensuring the stable operation of the system and the stack in the SOEC system, and at the same time affects the electrolytic water efficiency of the stack and further affects the system efficiency. The stack discharged air first flows through the first heat exchanger A1, conducts primary heat exchange with the incoming air to the stack, and then flows through the second heat exchanger B2. Such an arrangement is reasonable because the heat capacity of the stack discharged air exceeds the heat capacity of the incoming air to the stack, and the first heat exchanger A1 is not sufficient to fully utilize the heat of the discharged air. Further, the discharged air flows through the turbine 106, and then passes through the first three-way valve 107. The first three-way valve 107 controls the amount of recycled air discharged from the stack and the amount of air discharged to the atmosphere or the oxygen utilization occasion. The recycled air volume converges with the downstream air of the first solenoid valve 101. Thus, all or part of the air in the air supply system completes the circulating flow. The turbine 106 is arranged downstream of the SOEC discharged air, so as to utilize the pressure energy of the SOEC discharged air. The turbine 106 supplies power to the component 103 through the circuit S5, or the turbine 106 and the component 103 are coaxially designed to achieve kinetic energy transfer. In addition, 1 heat exchanger A1 is arranged in the air supply system, and the remaining 3 heat exchangers B1 to B3 are arranged in the liquid water supply system, and it is required that the third heat exchanger B3 is arranged upstream of the second heat exchanger B2. The liquid water source 213 can come from urban tap water or industrial wastewater with a certain temperature. First, it flows through the liquid water purification device 201 to remove the particulate impurities and metal ions in the tap water and wastewater. The pure water tank 202 of the liquid water supply device must be opened and connected to the atmosphere 214 to adjust the liquid level in the water tank. The outlet of the pure water tank 202 is connected to the inlet of the water pump 203. The water pump 203, as a key component of the liquid water supply system, provides the power for the medium flow in the system. The outlet of the water pump is connected to the low-temperature side inlet of the third heat exchanger B3, and the liquid water is heated by the secondary heat exchange of the hydrogen discharged from the stack, making full use of the heat of the discharged hydrogen.On the hot side of Heat Exchanger Three B3, the hydrogen discharged from the stack flows through, and on the hot side of Heat Exchanger Two B2, the air discharged from the stack flows through. Both are secondary heat exchanges of exhaust gas, making full use of the exhaust heat of the stack. The outlet at the cold side of Heat Exchanger Two B2 is the heated liquid water or vapor-liquid mixture, which further flows through the electric evaporator 204 to complete the vaporization of all liquid water. Subsequently, the vaporized steam converges with the incoming hydrogen upstream of Heat Exchanger Four B1 and jointly exchanges heat with the hydrogen discharged from the stack in the said Heat Exchanger Four B1, greatly utilizing the heat of the hydrogen discharged from the stack. The water vapor further enters the steam heater 205 to complete the temperature adjustment before entering the stack. The hydrogen discharged from the stack flows through Heat Exchanger Four B1 and Heat Exchanger Three B3 in sequence and enters the gas-liquid separator 212 at a lower temperature. The liquid water condensed in Heat Exchanger Three B3 is discharged to the pure water tank 202 via the check valve one 211, completing the recovery of the liquid water in the liquid water supply system. The hydrogen discharged from the gas-liquid separator 212 flows through the three-way valve two 206. Through the adjustment of the three-way valve two, part of the hydrogen flows out of the liquid water supply system and is discharged to the hydrogen downstream equipment 215 further downstream, and the remaining hydrogen flows through the solenoid valve two 207, and then through the reflux pump 208, the hydrogen mass flowmeter 209, and the check valve two 210, and converges with the incoming steam upstream of Heat Exchanger Four B1.

[0055] As shown in Table 1, the steam inlet system pressure > 4 bar(a). To ensure the gas pressures on both the anode and cathode sides of the stack are the same, otherwise it may cause cracking due to the pressure difference on both sides of the electrode and the electrolyte layer. At this time, the air path parameters are as shown in Table 2.

[0056] Table 2 SOEC system air path related parameters (based on Table 1)

[0057]

[0058] When the turbine 106 operates isentropically, the work done is analyzed as follows:

[0059] Inlet pressure: P out = 3.5 bar = 350 kPa (1)

[0060] Outlet pressure: P out = 1 atm ≈ 100 kPa (2)

[0061] Inlet temperature: T in = 250 °C ≈ 523 K (3)

[0062] Gas volume: m = 6115 kg / h ≈ 1.67 kg / s (4)

[0063] Specific heat capacity: c p = 1.005 kJ / (kg·K) (5)

[0064] Ideal gas turbine isentropic process

[0065] Among them, γ is the air specific volume ratio, with a value of 1.4

[0066] Specific enthalpy of inlet and outlet gases: h = c p ·T(7)

[0067] Enthalpy difference of inlet and outlet gases: Δh = h in -h out (8)

[0068] Theoretical external work done by the turbine 106: W t，s = m·Δh (9)

[0069] Substituting Equations 1 to 5 into Equations 6 to 9 in sequence, the isentropic work done by the turbine W t.s = m·Δh = 305 kW

[0070] In the industry, the isentropic efficiency of turbines is generally 70% - 90%. Conservatively taking 70%, at this time, the work done by the turbine is 305×70% = 214 kW

[0071] Under the conditions of this embodiment and system operation, fresh air or a mixture of fresh air and recirculated air enters the compressor 103 through the filter device 102. The reasonable value for the gas state before entering the compressor is normal pressure and normal temperature (1 atm, 25°C). As shown in Table 1 and Table 2, the gas pressure after the compressor needs to be increased to 4.5 bar(a). The gas temperature follows the compression pressure and is further heated to 750°C before entering the reactor through the downstream heat exchanger and heater. Furthermore, according to the work amount analysis formulas (1) - (9) for calculation, the isentropic power consumption of the compressor is 354 kW. In the machinery industry, the isentropic efficiencies of different types of compressors are shown in Table 3. Taking 80%, it can be known that the power consumption of the compressor is 354 / 80% = 443 kW

[0072] Table 3 Isentropic efficiencies of different types of compressors

[0073] Compressor type Centrifugal Axial Reciprocating Screw Isentropic efficiency 70％～85％ 80％～90％ 70％～85％ 75％～85％

[0074] In Embodiment 2, according to the present invention, the power consumption of the compressor 103 can be saved by 214 / 443 = 48%. This embodiment analyzes and calculates the SOEC system applied to the production industries of chemical products such as green methanol, green methane, and green ammonia, using the parameter operation conditions reported by foreign enterprise Sunfire

[0075] When the application industry and operation conditions change, it does not cause specific limitations to the protection scope of the present invention

[0076] As described above, the present invention can be better implemented. The above embodiments are only the best implementation modes of the present invention, but the implementation modes of the present invention are not limited by the above embodiments. Other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall all be equivalent replacement modes and are all included in the protection scope of the present invention.

Claims

1. A SOEC system architecture method for improving system efficiency, aiming at problems such as complex heat exchange components with unreasonable layout, poor selection of system component types, and unutilized energy other than thermal energy, is characterized in that It includes an air supply device, a liquid water supply device, a hydrogen storage / utilization device, an auxiliary starting system, and an electric energy supply device; the air supply device is supplied with atmospheric air source 109 through solenoid valve 1 (101). Solenoid valve 1 (101) opens, closes, or adjusts the opening degree according to strategy indicators such as the oxygen concentration during system operation, the temperature of the discharged air, and the stack voltage, thereby affecting the air supply volume of air source (109). The incoming air of air source (109) and the incoming air of the stack discharged air converge upstream of filter (102) and flow into filter (102). Blower or compressor (103) provides the power for the medium flow in the system and is powered by the electric energy supply system, converting electric energy into the heat energy and pressure energy of the incoming air. Part of the electric energy comes from circuit (S7), and part comes from circuit (S5). Utilizing these energies can improve the overall efficiency of the system; the liquid water supply device, water pump (203), provides the power for the medium flow in the system. Heat exchanger three (B3), the heat exchanger and the condenser are arranged in one, making full use of the cooling effect of liquid water to absorb heat from the hydrogen discharge preheater, and at the same time condensing and recovering the liquid water in the hydrogen discharge. The hydrogen storage / utilization device is for multi-stage compression and intermediate cooling, and is used to store the produced hydrogen during chemical production and energy storage peak shaving. The auxiliary starting device and the electric energy supply device are used as peripheral devices for system startup respectively.

2. The architecture method according to claim 1, wherein Downstream of blower or compressor * (103) of the air supply device, an air quality flowmeter (104) is arranged, which can detect the air supply volume of the stack. Before the air is supplied to the SOEC stack (301), it needs to flow through heat exchanger one (A1) and air heater (105) in sequence. Heat exchanger one (A1) can recover the heat of the stack discharged air; correct the temperature of the incoming air before entering the stack by air heater (105). The stack discharged air first flows through heat exchanger one (A1) for primary heat exchange, and then flows through heat exchanger two B2 to fully utilize the heat of the discharged air.

3. The architecture method according to claim 1, characterized in that The discharged air of the air supply device flows through turbine (106) and three-way valve 1 (107). Three-way valve 1 (107) can control the recycled amount of the stack discharged air and the amount of air discharged to the atmosphere or the oxygen utilization occasion.

4. The architecture method according to claim 1, characterized in that The recycled amount of air of the air supply device converges with the downstream air of solenoid valve 1 (101), and can complete all or part of the circulating flow of the air in the air supply SOEC system.

5. The architecture method according to claim 1 or 2 or 3 or 4, characterized in that Blower or compressor (103) of the air supply device provides the power for the medium flow in the air supply system. Turbine (106) is arranged downstream of the SOEC discharged air, which can utilize the pressure energy of the SOEC discharged air. Turbine (106) supplies power to blower or compressor (103) through circuit (S5) or the turbine (106) and the blower or compressor (103) are coaxial, and can directly transfer kinetic energy.

6. The architecture method according to claim 1, characterized in that The liquid water source (213) of the liquid water supply device is tap water or industrial wastewater at a temperature higher than the ambient temperature. It first flows through the liquid water purification device (201) to remove particulate impurities and metal ions in the water. The pure water tank (202) has an opening communicating with the atmospheric environment (214). The outlet of the pure water tank (202) is connected to the inlet of the water pump (203), which can adjust the liquid level in the pure water tank (202).

7. The architecture method according to claim 1, characterized in that The outlet of the water pump (203) of the liquid water supply device is connected to the low-temperature side inlet of the third heat exchanger (B3). The liquid water is heated by the secondary heat exchange of the hydrogen discharged by the stack. The third heat exchanger (B3) is placed upstream of the second heat exchanger (B2), and can use low-temperature liquid water to cool the discharged hydrogen, thereby condensing the water vapor contained in the discharged hydrogen.

8. The architecture method according to claim 1, characterized in that The hot side of the third heat exchanger B3 of the liquid water supply device flows through the hydrogen discharged by the stack, and the hot side of the second heat exchanger (B2) flows through the air discharged by the stack. Both are the secondary heat exchange using the exhaust heat of the stack.

9. The architecture method according to claim 1, characterized in that The cold side outlet of the second heat exchanger (B2) of the liquid water supply device is the heated liquid water or a liquid-vapor mixture. After being vaporized by the electric evaporator (204), it converges with the incoming hydrogen upstream of the fourth heat exchanger (B1). It can greatly utilize the heat of the hydrogen discharged by the stack to complete heat exchange in the fourth heat exchanger (B1) together. The water vapor enters the steam heater 205 to adjust the temperature before entering the stack. The hydrogen discharged by the stack flows through the fourth heat exchanger (B1) and the third heat exchanger (B3) in sequence, and enters the gas-liquid separator (212) at a lower temperature. The liquid water condensed in the third heat exchanger (B3) is discharged to the pure water tank (202) through the one-way valve one (211), and the recovery of liquid water in the liquid water supply system can be completed.

10. The architecture method according to claim 1 or 6 or 7 or 8 or 9, characterized in that The hydrogen discharged from the gas-liquid separator (212) of the liquid water supply device is adjusted by the three-way valve two (206). Part of the hydrogen flows out of the liquid water supply device and is discharged to the downstream hydrogen equipment (215). The remaining hydrogen flows through the solenoid valve two (207), and then through the reflux pump (208), the hydrogen mass flowmeter (209), and the one-way valve two (210), and converges with the incoming steam upstream of the fourth heat exchanger (B1).

11. The architecture method according to claim 1, characterized in that The "1 + 3" layout of the first heat exchanger (A1), the second heat exchanger (B2), the third heat exchanger (B3), and the fourth heat exchanger (B1) in the SOEC system architecture is to arrange 1 heat exchanger A1 in the air supply system, and arrange 3 heat exchangers, namely the fourth heat exchanger (B1), the second heat exchanger (B2), and the third heat exchanger (B3), in the liquid water supply device. The third heat exchanger (B3) is arranged upstream of the second heat exchanger (B2), which can make up for the insufficient heat discharge capacity of hydrogen relative to the heat absorption capacity of liquid water / steam and further expand the utilization of the air heat discharge capacity, improving the efficiency of the SOEC system.

12. The architecture method according to claim 1, characterized in that For the hydrogen storage / utilization device, the hydrogen from the three-way valve two (206) enters the hydrogen compression device (403), and flows through the first-stage compressor (404), the first-stage compression intermediate heat exchanger (405), the second-stage compressor (406), and the second-stage compression intermediate heat exchanger (407) in sequence. The incoming air path and water path cool the two intermediate heat exchangers (405, 407) respectively, which can reduce the energy consumption of the compressor and supplement the heat required by the SOEC system.

13. The architecture method according to claim 1, wherein On the other hand, for the hydrogen storage / utilization device, the hydrogen storage tank (401) and the nitrogen source (402) provide the gases required by the stack during the startup process of the stack to assist the startup of the SOEC system.

14. The architecture method according to claim 1, wherein The hydrogen storage / utilization device includes a hydrogen storage tank (401), a nitrogen source (402), and a hydrogen compression device (403). The hydrogen discharged from the stack passes through the hydrogen compression device (403), and the hydrogen is compressed into the hydrogen storage tank (401) under a certain pressure, which can improve the hydrogen storage density.

15. The architecture method according to claim 1 or 12 or 13 or 14, characterized in that The hydrogen storage / utilization device can be set according to the system power and hydrogen production amount, and is not limited to two-stage compression and intermediate cooling.

16. The architecture method according to claim 1 is characterized in that The electric energy supply device includes an SOEC stack (301), industrial alternating current (302), and an AC / DC converter (303). The industrial alternating current (302) supplies power for electrolyzing water to the SOEC stack (301) through the AC / DC converter (303), and supplies power to the blower or compressor (103), the air heater (105), the water pump (203), the electric evaporator (204), and the steam heater (205) through the circuits (S1~S4), (S6, S7) respectively.

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