Efficient vanadium-hydrogen integrated system based on thermal cycle and control method thereof

Abstract

The invention discloses an efficient vanadium-hydrogen integrated system based on thermal cycle and a control method thereof, and relates to the technical field of electric energy storage. Comprising an all-vanadium redox flow energy storage system and a hydrogen production system, the all-vanadium redox flow energy storage system comprises an electric pile, a first liquid storage tank, a second liquid storage tank, a positive electrode electrolyte arranged in the first liquid storage tank, a negative electrode electrolyte arranged in the second liquid storage tank, a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger, the first heat exchanger and the second heat exchanger are located in the first liquid storage tank and the second liquid storage tank respectively, and the third heat exchanger and the fourth heat exchanger are located outside the first liquid storage tank and the second liquid storage tank respectively. The first heat exchanger and the second heat exchanger are connected with the heating source and the waste heat utilization unit through pipelines; and the third heat exchanger and the fourth heat exchanger are connected with the heat utilization unit through pipelines. The energy consumption of the integrated system is effectively reduced, and the overall operation efficiency of the system is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric energy storage, and in particular relates to a high-efficiency vanadium-hydrogen integrated system based on thermal cycle and a control method thereof. Background Art

[0002] Compared with the grid-connected hydrogen production mode, the existing off-grid hydrogen production can improve system efficiency, reduce construction period and dependence on the power grid, but its volatility is difficult to match with the hydrogen production equipment, and an energy storage system needs to be configured to ensure the stability of the hydrogen production power supply.

[0003] All-vanadium liquid flow energy storage is a type of electrochemical energy storage, which has the advantages of large scale, flexible layout, high safety, long charge and discharge cycle life, and low cost per kilowatt-hour in the whole life cycle. Therefore, the all-vanadium liquid flow energy storage station can be used in conjunction with the off-grid hydrogen production system. However, the electrolyte of the all-vanadium liquid flow energy storage system has high requirements for the working temperature. Too high or too low temperature can easily cause the positive and negative electrolytes to crystallize and precipitate. The application of the all-vanadium liquid flow energy storage system in high or low temperature environments is severely restricted by the normal working temperature, and its working temperature is 0-40°C. At present, in engineering applications, when the all-vanadium liquid flow energy storage system is working normally, a set of evaporative refrigeration system is configured to dissipate heat, so that the electrolyte working temperature is reduced to the optimal working temperature range; in the standby or shutdown state in a cold environment, a heating belt is configured to raise the electrolyte temperature to above 0°C. Therefore, the all-vanadium liquid flow energy storage system requires additional energy to maintain the temperature range requirements of the electrolyte, which brings additional energy loss and affects the system operation and standby efficiency. The hydrogen production system is a hot and cold electrical multi-energy flow system. When the electrolyzer is in operation, a lot of heat will be generated, causing the electrolyte to heat up. If the overall temperature of the electrolyzer is too high, it will greatly affect the hydrogen production efficiency. At the same time, its purification system requires additional heat to provide an operating environment. The hydrogen purification system requires additional heat to meet the needs of its hydrogen-oxygen reaction and desiccant regeneration. Therefore, how to combine the topological structure characteristics and heat utilization of the hydrogen production system and the all-vanadium liquid flow energy storage system to achieve the comprehensive utilization of energy and equipment, effectively reduce the energy consumption of the hydrogen storage integrated system, and improve the system operation efficiency requires the invention of an efficient vanadium-hydrogen integrated system based on thermal cycle and its control method. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the above-mentioned background technology and to provide a high-efficiency vanadium-hydrogen integrated system based on thermal cycle and a control method thereof.

[0005] The technical solution adopted by the present invention is: a high-efficiency vanadium-hydrogen integrated system based on thermal cycle, including an all-vanadium liquid flow energy storage system and a hydrogen production system, the all-vanadium liquid flow energy storage system includes a fuel cell, a first liquid storage tank, a second liquid storage tank, and a positive electrode electrolyte respectively placed in the first liquid storage tank and a negative electrode electrolyte in the second liquid storage tank, a first heat exchanger and a second heat exchanger arranged in parallel, and a third heat exchanger and a fourth heat exchanger arranged in parallel, the first heat exchanger and the second heat exchanger are respectively located inside the first liquid storage tank and the second liquid storage tank, the third heat exchanger and the fourth heat exchanger are respectively located outside the first liquid storage tank and the second liquid storage tank, the fuel cell is respectively connected to the positive electrode electrolyte in the first liquid storage tank and the negative electrode electrolyte in the second liquid storage tank through pipelines, the fuel cell is respectively connected to the third heat exchanger and the fourth heat exchanger through pipelines, and the third heat exchanger and the fourth heat exchanger are respectively connected to the positive electrode electrolyte in the first liquid storage tank and the negative electrode electrolyte in the second liquid storage tank through pipelines;

[0006] The first heat exchanger and the second heat exchanger are connected to the heating heat source and the waste heat utilization unit through pipelines; the third heat exchanger and the fourth heat exchanger are connected to the heat using unit through pipelines;

[0007] The hydrogen production system comprises a hydrogen production system heat unit and a hydrogen production system heat dissipation unit;

[0008] The heating heat source includes an external heat source and a hydrogen production system electrolyte heat exchanger located in a heat dissipation unit of the hydrogen production system;

[0009] The heat-using unit includes a heating load, a hydrogen production purification system located in the heat-using unit of the hydrogen production system, and circulating cooling water in the hydrogen production station.

[0010] Furthermore, the first heat exchanger, the second heat exchanger, the electrolyte heat exchanger of the hydrogen production system and the inlet and outlet of the external heat source are connected through pipelines.

[0011] Furthermore, the inlet and outlet of the first heat exchanger, the second heat exchanger and the waste heat utilization unit are connected through pipelines.

[0012] Furthermore, the third heat exchanger and the fourth heat exchanger are connected to the hydrogen production and purification system, the heating load and the inlet and outlet of circulating cooling water in the hydrogen production station through pipelines.

[0013] A control method for a high-efficiency vanadium-hydrogen integrated system based on a thermal cycle includes a heating regulation method, wherein the heating regulation method includes the following steps:

[0014] 1) Collecting the positive electrolyte and negative electrolyte temperature T of the all-vanadium liquid flow energy storage system in the standby or shutdown state;

[0015] 2) Determine whether T meets the operating temperature range [T1, T2], if yes, go to step 8), if not, go to step 3);

[0016] 3) Open the valves connecting the inlet of the first heat exchanger and the second heat exchanger of the all-vanadium liquid flow energy storage system to the high-temperature end of the electrolyte heat exchanger of the hydrogen production system, and use the heat generated by the electrolyzer of the hydrogen production system to heat the electrolyte;

[0017] 4) Collecting the temperature T of the positive electrode electrolyte and the negative electrode electrolyte after heating the electrolyte, and judging whether T meets the working temperature range [T1, T2], if so, proceeding to step 6), if not, proceeding to step 5);

[0018] 5) Close the valves of the first and second heat exchangers of the all-vanadium liquid flow energy storage system connected to the high-temperature end of the electrolyte heat exchanger of the hydrogen production system, open the valves of the first and second heat exchangers of the all-vanadium liquid flow energy storage system connected to the external heat source, use the external heat source to supplement heat, and enter step 4);

[0019] 6) Determine whether the temperature of the heat exchange medium at the outlet of the first heat exchanger and the second heat exchanger meets the heating requirement of the waste heat utilization unit. If yes, proceed to step 7); if not, proceed to step 8);

[0020] 7) The heat exchange medium at the outlets of the first heat exchanger and the second heat exchanger continues to provide heat for the waste heat utilization unit;

[0021] 8) The electrolyte that meets the temperature requirements flows back to the first liquid storage tank and the second liquid storage tank.

[0022] A control method for a high-efficiency vanadium-hydrogen integrated system based on a thermal cycle includes a heat dissipation adjustment method, wherein the heat dissipation adjustment method includes the following steps:

[0023] 1) Collect the temperature T of the positive and negative electrolytes at the outlet of the stack when the all-vanadium liquid flow energy storage system is running;

[0024] 2) Determine whether T meets the operating temperature range [t1, t2], if yes, go to step 10), if not, go to step 3);

[0025] 3) Determine whether the heat carried by the electrolyte of the all-vanadium liquid flow energy storage system can meet the heat demand of the hydrogen production and purification system. If so, proceed to step 4); otherwise, proceed to step 6);

[0026] 4) Open the valves connecting the inlet of the third heat exchanger and the fourth heat exchanger of the all-vanadium liquid flow energy storage system to the hydrogen production and purification system, and use the heat generated by the all-vanadium liquid flow energy storage system when it is working to preheat the hydrogen production and purification system;

[0027] 5) Collect the temperature T of the positive electrode electrolyte and the negative electrode electrolyte after preheating the hydrogen production and purification system, and determine whether T meets the working temperature range [t1, t2]. If so, proceed to step 10); if not, proceed to step 6);

[0028] 6) Determine whether the heat of the electrolyte of the all-vanadium liquid flow energy storage system can meet the heat demand of the heating load, if yes, proceed to step 7), if not, proceed to step 9);

[0029] 7) Open the valves connecting the inlet of the third and fourth heat exchangers of the all-vanadium liquid flow energy storage system to the heating load, and use the electrolyte heat of the all-vanadium liquid flow energy storage system to provide heat for the heating load;

[0030] 8) Collect the temperature T of the positive electrode electrolyte and the negative electrode electrolyte after heating the heating load, and determine whether T meets the working temperature range [t1, t2]. If so, proceed to step 10); if not, proceed to step 9);

[0031] 9) Using circulating cooling water in the hydrogen production station to dissipate heat until the electrolyte operating temperature meets the operating temperature range [t1, t2];

[0032] 10) The electrolyte that meets the temperature requirements flows back to the first liquid storage tank and the second liquid storage tank.

[0033] The present invention utilizes the heat generated during the operation of the electrolyzer of the hydrogen production system to heat the electrolyte of the all-vanadium liquid flow energy storage system in a low-temperature shutdown state, thereby raising the electrolyte temperature to within the working range, effectively utilizing the heat of the hydrogen production system, reducing additional energy loss, and effectively improving the operating efficiency of the all-vanadium liquid flow energy storage system under low-temperature conditions; the heat generated during the operation of the all-vanadium liquid flow energy storage system is first used for preheating the hydrogen production purification system or for heating loads, and when there is still excess heat, the circulating cooling water system in the hydrogen production station is used for cooling, effectively utilizing the heat generated during the operation of the all-vanadium liquid flow energy storage system, reducing the additional energy required for purification and heating of the hydrogen production system, and utilizing the existing cooling device of the hydrogen production system for cooling and heat dissipation, thereby eliminating the evaporative refrigeration device originally provided with the all-vanadium liquid flow energy storage system, and effectively improving the overall efficiency and economy of the vanadium-hydrogen integrated system.

[0034] The present invention has the following beneficial effects:

[0035] 1. The heat generated by the operation of the electrolyzer of the hydrogen production system is used to heat the electrolyte of the all-vanadium liquid flow energy storage system, which effectively utilizes the waste heat of the electrolyzer and reduces the additional energy consumption for heating the all-vanadium liquid flow electrolyte, which can effectively improve the efficiency and energy utilization rate of the vanadium-hydrogen integrated system;

[0036] 2. The waste heat from the hydrogen production system electrolyzer heating the all-vanadium liquid flow electrolyte can be further used for heating load in the station, realizing the energy cascade utilization of the vanadium-hydrogen integrated system;

[0037] 3. The heat generated by the all-vanadium liquid flow energy storage system during operation preheats the hydrogen production and purification system or the heating load in the station, which reduces the electrolyte temperature of the all-vanadium liquid flow energy storage system and reduces the additional energy required for purification and heating of the hydrogen production system;

[0038] 4. After being purified and preheated by the hydrogen production system or heated by the heating load in the station, the remaining heat of the all-vanadium liquid flow energy storage electrolyte is cooled by the circulating cooling water system in the hydrogen production station, eliminating the original evaporative refrigeration system, which can effectively improve the overall efficiency and economy of the system;

[0039] 5. The vanadium-hydrogen integrated system based on thermal cycle proposed in the present invention effectively reduces the energy consumption of the integrated system and improves the overall operating efficiency of the system. In addition, the vanadium-hydrogen integrated system shares the circulating cooling water equipment in the station, which saves equipment investment and improves the economy of the integrated system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the circulation of the heat self-made hydrogen system to the all-vanadium liquid flow energy storage system;

[0041] Figure 2 It is a flow chart of the circulation of the heat self-made hydrogen system to the all-vanadium liquid flow energy storage system;

[0042] Figure 3 It is a schematic diagram of the circulation of heat from the all-vanadium liquid flow energy storage system to the hydrogen production system;

[0043] Figure 4 It is a flow chart of the circulation of heat from the all-vanadium liquid flow energy storage system to the hydrogen production system;

[0044] Figure 5 This is a structural diagram of the high-efficiency vanadium-hydrogen integrated system based on thermal cycle of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but they do not constitute a limitation on the present invention.

[0046] Embodiment 1

[0047] like Figure 1 , Figure 3 , Figure 5As shown, the present invention provides a high-efficiency vanadium-hydrogen integrated system based on thermal cycle, including an all-vanadium liquid flow energy storage system and a hydrogen production system, the all-vanadium liquid flow energy storage system includes a fuel cell, a first liquid storage tank 106, a second liquid storage tank 107, and a positive electrode electrolyte placed in the first liquid storage tank 106, a negative electrode electrolyte placed in the second liquid storage tank 107, a first heat exchanger 104 and a second heat exchanger 105 arranged in parallel, a third heat exchanger 108 and a fourth heat exchanger 109 arranged in parallel, the first heat exchanger 104 and the second heat exchanger 105 are respectively located in the first liquid storage tank 106 and the second liquid storage tank 107. 6. Inside the second liquid storage tank 107, the third heat exchanger 108 and the fourth heat exchanger 109 are respectively located outside the first liquid storage tank 106 and the second liquid storage tank 107, the battery stack is respectively connected to the positive electrode electrolyte in the first liquid storage tank 106 and the negative electrode electrolyte in the second liquid storage tank 107 through pipelines, the battery stack is respectively connected to the third heat exchanger 108 and the fourth heat exchanger 109 through pipelines, and the third heat exchanger 108 and the fourth heat exchanger 109 are respectively connected to the positive electrode electrolyte in the first liquid storage tank 106 and the negative electrode electrolyte in the second liquid storage tank 107 through pipelines;

[0048] The first heat exchanger 104 and the second heat exchanger 105 are connected to the heating heat source A1 and the waste heat utilization unit 101 through pipelines; the third heat exchanger 108 and the fourth heat exchanger 109 are connected to the heat using unit A2 through pipelines;

[0049] The hydrogen production system includes a hydrogen production system heat unit B1 and a hydrogen production system heat dissipation unit B2;

[0050] The heating heat source A1 includes an external heat source 102 and a hydrogen production system electrolyte heat exchanger 103 located in the hydrogen production system heat dissipation unit B2;

[0051] The heat unit A2 includes a heating load 202, a hydrogen production purification system 201 located in the heat unit B1 of the hydrogen production system, and circulating cooling water 203 in the hydrogen production station.

[0052] The first heat exchanger 104, the second heat exchanger 105, the inlet and outlet of the hydrogen production system electrolyte heat exchanger 103 and the external heat source 102 are connected through pipelines.

[0053] The first heat exchanger 104, the second heat exchanger 105 and the inlet and outlet of the waste heat utilization unit 101 are connected through pipelines.

[0054] The third heat exchanger 108 and the fourth heat exchanger 109 are connected to the inlet and outlet of the hydrogen production and purification system 201, the heating load 202 and the circulating cooling water 203 in the hydrogen production station through pipelines.

[0055] In this embodiment, the external heat source 102 includes but is not limited to electric heating, heat pump, and hydrogen combustion.

[0056] In this embodiment, the structures of the first heat exchanger 104, the second heat exchanger 105, the third heat exchanger 108, and the fourth heat exchanger 109 include but are not limited to plate type and shell and tube type.

[0057] In this embodiment, the first heat exchanger 104, the second heat exchanger 105, the third heat exchanger 108, and the fourth heat exchanger 109 are filled with heat carriers. Specifically, the heat carriers can be liquid working fluids, phase change heat storage materials, or granular heat storage working fluids with a certain fluidity.

[0058] In the above scheme, the hydrogen production system is a conventional hydrogen production system, refer to the paper "Simulation Research on Thermal Management System of Alkaline Water Electrolysis Hydrogen Production Device".

[0059] The working principle of the present invention is as follows: the heat generated by the electrolytic cell of the hydrogen production system in the heat dissipation unit B2 of the hydrogen production system is used to heat the positive electrolyte and the negative electrolyte of the all-vanadium liquid flow energy storage system through the first heat exchanger 104 and the second heat exchanger 105. When the heat cannot meet the needs of the positive electrolyte and the negative electrolyte of the all-vanadium liquid flow energy storage system, the external heat source 102 is used to supplement the heat. When the heat meets the needs of the positive electrolyte and the negative electrolyte of the all-vanadium liquid flow energy storage system and there is still surplus heat, the waste heat is used in the waste heat utilization unit 101; the heat generated during the operation of the all-vanadium liquid flow energy storage system is used to preheat the hydrogen production and purification system 201 or the heating load 202. When there is still surplus heat, the circulating cooling water 203 in the hydrogen production station in the heat unit B1 of the hydrogen production system is used to take away the surplus heat.

[0060] The present invention heats the electrolyte of the all-vanadium liquid flow energy storage system in a low-temperature shutdown state, raises the electrolyte temperature to above 0°C, and further uses the remaining heat for the heating load, thereby reducing the extra energy consumed to maintain the electrolyte temperature while utilizing the heat of the hydrogen production system in a cascade manner; the heat generated by the all-vanadium liquid flow energy storage system during operation is first used to preheat the hydrogen production purification system 201 or the heating load 202, and when there is still excess heat, the circulating cooling water 203 system in the hydrogen production station is used for cooling and dissipation, thereby effectively utilizing the heat generated during the operation of the all-vanadium liquid flow energy storage system, reducing the extra energy required for purification and heating of the hydrogen production system, and utilizing the cooling device of the hydrogen production system for cooling and dissipating heat, thereby canceling the evaporative refrigeration system originally equipped with the all-vanadium liquid flow energy storage system, thereby effectively improving the overall efficiency and economy of the vanadium-hydrogen integrated system.

[0061] Embodiment 2:

[0062] like Figure 1As shown, the system provided in this embodiment for circulating the heat from the self-made hydrogen system to the all-vanadium liquid flow energy storage system includes the positive electrolyte, the negative electrolyte, the fuel cell stack, the first liquid storage tank 106, and the second liquid storage tank 107 of the all-vanadium liquid flow energy storage system; the first heat exchanger 104 and the second heat exchanger 105 arranged in parallel; the heating heat source A1, which includes the hydrogen production system electrolyte heat exchanger 103 and the external heat source 102; the waste heat utilization unit 101, and the waste heat utilization unit 101 includes heating and other heat loads.

[0063] The heating cycle process of the all-vanadium liquid flow energy storage system of this embodiment is described in detail below.

[0064] The operating temperature range of the positive and negative electrolytes of the all-vanadium liquid flow energy storage system is [0°C, 40°C]. Temperature sensors are respectively set in the positive and negative electrolytes to provide real-time feedback of the electrolyte temperature.

[0065] When the all-vanadium liquid flow energy storage system is in shutdown or standby state, and the ambient temperature is low so that the electrolyte temperature is lower than 0°C, the valves connecting the inlets of the first heat exchanger 104 and the second heat exchanger 105 of the all-vanadium liquid flow energy storage system to the high-temperature end of the electrolyte heat exchanger 103 of the hydrogen production system are opened, and the heat generated by the electrolytic cell of the hydrogen production system is used to heat the electrolyte;

[0066] When the residual heat of the electrolyzer of the hydrogen production system continues to supply heat, the electrolyte temperature of the all-vanadium liquid flow energy storage system is still below 0°C, close the valves of the first heat exchanger 104 and the second heat exchanger 105 of the all-vanadium liquid flow energy storage system connected to the high-temperature end of the electrolyte heat exchanger 103 of the hydrogen production system, open the valves of the first heat exchanger 104 and the second heat exchanger 105 of the all-vanadium liquid flow energy storage system connected to the external heat source 102, and use external heat sources such as heat pumps, electric heating, and hydrogen combustion to supplement heat until the temperature meets the [0°C, 40°C] range requirements;

[0067] Temperature sensors are provided at the outlets of the first heat exchanger 104 and the second heat exchanger 105 to measure and feedback the outlet temperatures of the heat exchange medium of the first heat exchanger 104 and the second heat exchanger 105. When the demand of the waste heat utilization unit 101 is met, the outlet carriers of the first heat exchanger 104 and the second heat exchanger 105 continue to provide heat for the waste heat utilization unit 101.

[0068] like Figure 2 As shown, the heating regulation method of the all-vanadium liquid flow energy storage system of this embodiment is described in detail below.

[0069] 1) Collecting the positive electrolyte and negative electrolyte temperature T of the all-vanadium liquid flow energy storage system in the standby or shutdown state;

[0070] 2) Determine whether T meets the operating temperature range [T1, T2], if yes, go to step 8), if not, go to step 3);

[0071] 3) Open the valves connecting the inlet of the first heat exchanger 104 and the second heat exchanger 105 of the all-vanadium liquid flow energy storage system to the high-temperature end of the electrolyte heat exchanger 103 of the hydrogen production system, and use the heat generated by the electrolyzer of the hydrogen production system to heat the electrolyte;

[0072] 4) Determine whether T meets the operating temperature range [T1, T2], if yes, go to step 6), if not, go to step 5);

[0073] 5) Close the valves of the first heat exchanger 104 and the second heat exchanger 105 of the all-vanadium liquid flow energy storage system connected to the high-temperature end of the electrolyte heat exchanger 103 of the hydrogen production system, open the valves of the first heat exchanger 104 and the second heat exchanger 105 of the all-vanadium liquid flow energy storage system connected to the external heat source 102, and use heat pumps, electric heating, hydrogen combustion and other external heat sources to supplement heat, and enter step 4);

[0074] 6) Determine whether the outlet temperatures of the heat exchange medium of the first heat exchanger 104 and the second heat exchanger 105 can meet the heating requirements of the waste heat utilization unit 101. If yes, proceed to step 7); if not, proceed to step 8);

[0075] 7) The heat exchange medium at the outlets of the first heat exchanger 104 and the second heat exchanger 105 continues to provide heat for the waste heat utilization unit 101;

[0076] 8) The electrolyte that meets the temperature requirements flows back to the first liquid storage tank 106 and the second liquid storage tank 107.

[0077] For a 250MW photovoltaic hydrogen production project, nine 1000Nm 3 / h, and configure the energy storage system at a scale of 20%, that is, configure a 50MW / 200MWh energy storage system. The power required for 50MW / 200MWh electrolyte heating is about 1.67MW.

[0078] 1000Nm 3 / h electrolyzer produces about 0.95MW of waste heat, 9 1000Nm 3 / hThe waste heat generated by the electrolyzer is about 8.55MW, and the usable waste heat is about 4.275MW. The heat generated by the operation of the hydrogen production electrolyzer can meet all the heat required for heating the electrolyte of the all-vanadium liquid flow energy storage system. The heat generated by the operation of the hydrogen production electrolyzer can be effectively utilized. Considering that when the all-vanadium liquid flow energy storage is shut down, the operating time of the heating system accounts for 50%, and the utilization rate of the electrolyzer waste heat is increased by about 20%.

[0079] Embodiment three:

[0080] like Figure 3As shown, the system provided by this embodiment for circulating heat from the all-vanadium liquid flow energy storage system to the hydrogen production system includes the positive electrolyte, the negative electrolyte, the fuel cell stack, the first liquid storage tank 106, the second liquid storage tank 107, which includes the third heat exchanger 108, the fourth heat exchanger 109, the low-temperature side flow channel of the heat exchanger, and the high-temperature side flow channel of the heat exchanger arranged in parallel; the heat unit A2, the heat unit A2 includes the hydrogen production and purification system 201, the heating load 202, and the circulating cooling water 203 in the hydrogen production station.

[0081] The heating cycle process of the all-vanadium liquid flow energy storage system of this embodiment is described in detail below.

[0082] The operating temperature range of the positive electrolyte and the negative electrolyte of the all-vanadium liquid flow energy storage system is [30°C, 40°C]. Temperature sensors are respectively set in the positive electrolyte and the negative electrolyte to feedback the electrolyte temperature;

[0083] During the operation of the all-vanadium liquid flow energy storage system, when the electrolyte temperature is higher than 40°C, the valve connected to the input end of the hydrogen production and purification system 201 / heating load 202 is opened, and the heat generated during the operation of the all-vanadium liquid flow energy storage system is used to heat the hydrogen production and purification system 201 / heating load 202. The hydrogen production and purification system 201 / heating load 202 has the following combinations:

[0084] 1. The heat generated during the operation of the all-vanadium liquid flow energy storage system firstly heats the hydrogen production and purification system 201, and the remaining heat further heats the heating load 202;

[0085] 2. The heat generated during the operation of the all-vanadium liquid flow energy storage system is only used to heat the hydrogen production and purification system 201;

[0086] 3. The heat generated during the operation of the all-vanadium liquid flow energy storage system is only used to heat the heating load 202.

[0087] When the heat exchange of the hydrogen production purification system 201 / heating load 202 is insufficient to make the electrolyte temperature meet the [30°C, 40°C] range requirement, the valve connected to the input end of the circulating cooling water 203 in the hydrogen production station is further opened to use the circulating cooling water in the station to dissipate heat until the electrolyte temperature meets the [30°C, 40°C] range requirement.

[0088] like Figure 4 As shown, the heat dissipation adjustment method of the all-vanadium liquid flow energy storage system of this embodiment is described in detail below.

[0089] 1) Collect the temperature T of the positive and negative electrolytes at the stack outlet when the all-vanadium liquid flow energy storage system is running;

[0090] 2) Determine whether T satisfies the optimal operating temperature range of the electrolyte [t1, t2]. If so, proceed to step 10); if not, proceed to step 3);

[0091] 3) Determine whether the heat carried by the electrolyte of the all-vanadium liquid flow energy storage system can meet the heat demand of the hydrogen production and purification system 201. If it can be met, proceed to step 4); otherwise, proceed to step 6);

[0092] 4) Open the valves connecting the inlets of the third heat exchanger 108 and the fourth heat exchanger 109 of the all-vanadium liquid flow energy storage system to the hydrogen production and purification system 201, and use the heat generated by the all-vanadium liquid flow energy storage system when it is working to preheat the purification system 201;

[0093] 5) Collect the electrolyte temperature T after preheating the hydrogen production and purification system 201, and determine whether the electrolyte temperature meets the temperature range [t1, t2]. If so, proceed to step 10); if not, proceed to step 6);

[0094] 6) Determine whether the heat of the electrolyte of the all-vanadium liquid flow energy storage system can meet the heat demand of the heating load 202. If it can be met, proceed to step 7); if it cannot be met, proceed to step 9);

[0095] 7) Open the valves connecting the inlets of the third heat exchanger 108 and the fourth heat exchanger 109 of the all-vanadium liquid flow energy storage system to the heating load 202, and use the electrolyte heat of the all-vanadium liquid flow energy storage system to provide heat for the heating load 202;

[0096] 8) Collect the electrolyte temperature T after heating by the heating system, and determine whether it meets the optimal working temperature range of the electrolyte [t1, t2]. If so, proceed to step 10); if not, proceed to step 9);

[0097] 9) Using the circulating cooling water 203 in the hydrogen production station to dissipate heat until the electrolyte working temperature meets the [t1, t2] requirements;

[0098] 10) The electrolyte that meets the temperature requirements flows back to the first liquid storage tank 106 and the second liquid storage tank 107.

[0099] For a 250MW photovoltaic hydrogen production project, nine 1000Nm 3 / h, and configure the energy storage system at a scale of 20%, that is, configure a 50MW / 200MWh energy storage system. The power required for 50MW / 200MWh electrolyte cooling is about 2MW.

[0100] 1000Nm 3 / h purification heating power consumption is about 0.056MW, 9 units 1000Nm 3 / h purification heating power consumption is about 0.504MW. The heat carried by the electrolyte of the all-vanadium liquid flow energy storage system can be used to heat the hydrogen production purification system 201. Considering that the operation time of the all-vanadium liquid flow energy storage heating system accounts for 50%, the heating power of the hydrogen production purification system 201 can be reduced by about 10%. For the all-vanadium liquid flow energy storage system, the efficiency of the all-vanadium liquid flow energy storage system can be improved by 2% through preheating the hydrogen production purification system 201, supplying heating load 202 and dissipating heat by circulating cooling water 203 in the hydrogen production station.

[0101] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A high-efficiency vanadium-hydrogen integrated system based on thermal cycle, characterized by: The invention comprises an all-vanadium liquid flow energy storage system and a hydrogen production system, wherein the all-vanadium liquid flow energy storage system comprises a battery stack, a first liquid storage tank (106), a second liquid storage tank (107), and a positive electrode electrolyte respectively placed in the first liquid storage tank (106), a negative electrode electrolyte respectively placed in the second liquid storage tank (107), a first heat exchanger (104) and a second heat exchanger (105) arranged in parallel, and a third heat exchanger (108) and a fourth heat exchanger (109) arranged in parallel, wherein the first heat exchanger (104) and the second heat exchanger (105) are respectively located inside the first liquid storage tank (106) and the second liquid storage tank (107). The third heat exchanger (108) and the fourth heat exchanger (109) are respectively located outside the first liquid storage tank (106) and the second liquid storage tank (107); the battery stack is respectively connected to the positive electrode electrolyte in the first liquid storage tank (106) and the negative electrode electrolyte in the second liquid storage tank (107) through pipelines; the battery stack is respectively connected to the third heat exchanger (108) and the fourth heat exchanger (109) through pipelines; the third heat exchanger (108) and the fourth heat exchanger (109) are respectively connected to the positive electrode electrolyte in the first liquid storage tank (106) and the negative electrode electrolyte in the second liquid storage tank (107) through pipelines; The first heat exchanger (104) and the second heat exchanger (105) are connected to the heating heat source (A1) and the waste heat utilization unit (101) through pipelines; the third heat exchanger (108) and the fourth heat exchanger (109) are connected to the heat using unit (A2) through pipelines; The hydrogen production system comprises a hydrogen production system heat unit (B1) and a hydrogen production system heat dissipation unit (B2); The heating heat source (A1) includes an external heat source (102) and a hydrogen production system electrolyte heat exchanger (103) located in a hydrogen production system heat dissipation unit (B2); The heat-using unit (A2) includes a heating load (202), a hydrogen production purification system (201) located in the heat-using unit (B1) of the hydrogen production system, and circulating cooling water (203) in the hydrogen production station.

2. The high-efficiency vanadium-hydrogen integrated system based on thermal cycle according to claim 1, characterized in that: The first heat exchanger (104), the second heat exchanger (105), the electrolyte heat exchanger (103) of the hydrogen production system and the inlet and outlet of the external heat source (102) are connected through pipelines.

3. The high-efficiency vanadium-hydrogen integrated system based on thermal cycle according to claim 1, characterized in that: The first heat exchanger (104), the second heat exchanger (105) and the inlet and outlet of the waste heat utilization unit (101) are connected via pipelines.

4. The high-efficiency vanadium-hydrogen integrated system based on thermal cycle according to claim 1, characterized in that: The third heat exchanger (108), the fourth heat exchanger (109), the inlet and outlet of the hydrogen production and purification system (201), the heating load (202) and the circulating cooling water (203) in the hydrogen production station are connected through pipelines.

5. The control method of a high-efficiency vanadium-hydrogen integrated system based on thermal cycle according to claim 1, characterized in that: The invention comprises a heating regulation method, wherein the heating regulation method comprises the following steps: 1) Collecting the positive electrolyte and negative electrolyte temperature T of the all-vanadium liquid flow energy storage system in the standby or shutdown state; 2) Determine whether T meets the operating temperature range [T1, T2], if yes, go to step 8), if not, go to step 3); 3) opening the valves connecting the inlet of the first heat exchanger (104) and the second heat exchanger (105) of the all-vanadium liquid flow energy storage system to the high-temperature end of the electrolyte heat exchanger (103) of the hydrogen production system, and using the heat generated by the electrolytic cell of the hydrogen production system to heat the electrolyte; 4) Collecting the temperature T of the positive electrode electrolyte and the negative electrode electrolyte after heating the electrolyte, and judging whether T meets the working temperature range [T1, T2], if so, proceeding to step 6), if not, proceeding to step 5); 5) Close the valves of the first heat exchanger (104) and the second heat exchanger (105) of the all-vanadium liquid flow energy storage system connected to the high-temperature end of the electrolyte heat exchanger (103) of the hydrogen production system, open the valves of the first heat exchanger (104) and the second heat exchanger (105) of the all-vanadium liquid flow energy storage system connected to the external heat source (102), use the external heat source (102) to supplement heat, and enter step 4); 6) Determine whether the temperature of the heat exchange medium at the outlet of the first heat exchanger (104) and the second heat exchanger (105) meets the heating requirement of the waste heat utilization unit (101); if so, proceed to step 7); if not, proceed to step 8); 7) The heat exchange medium at the outlets of the first heat exchanger (104) and the second heat exchanger (105) continues to provide heat for the waste heat utilization unit (101); 8) The electrolyte that meets the temperature requirements flows back to the first liquid storage tank (106) and the second liquid storage tank (107).

6. The control method of a high-efficiency vanadium-hydrogen integrated system based on thermal cycle according to claim 1, characterized in that: The invention comprises a heat dissipation adjustment method, wherein the heat dissipation adjustment method comprises the following steps: 1) Collect the temperature T of the positive and negative electrolytes at the outlet of the stack when the all-vanadium liquid flow energy storage system is running; 2) Determine whether T meets the operating temperature range [t1, t2], if yes, go to step 10), if not, go to step 3); 3) Determine whether the heat carried by the electrolyte of the all-vanadium liquid flow energy storage system can meet the heat demand of the hydrogen production and purification system. If so, proceed to step 4); otherwise, proceed to step 6); 4) opening the valves connecting the inlets of the third heat exchanger (108) and the fourth heat exchanger (109) of the all-vanadium liquid flow energy storage system to the hydrogen production and purification system (201), and using the heat generated by the all-vanadium liquid flow energy storage system when it is working to preheat the hydrogen production and purification system (201); 5) collecting the temperature T of the positive electrode electrolyte and the negative electrode electrolyte after preheating the hydrogen production and purification system (201), and judging whether T meets the working temperature range [t1, t2]; if so, proceeding to step 10); if not, proceeding to step 6); 6) Determine whether the heat of the electrolyte of the all-vanadium liquid flow energy storage system can meet the heat demand of the heating load (202), if so, proceed to step 7), if not, proceed to step 9); 7) Opening the valves connecting the inlets of the third heat exchanger (108) and the fourth heat exchanger (109) of the all-vanadium liquid flow energy storage system to the heating load (202), and using the electrolyte heat of the all-vanadium liquid flow energy storage system to provide heat for the heating load (202); 8) Collect the temperature T of the positive electrode electrolyte and the negative electrode electrolyte after heating the heating load (202), and determine whether T meets the working temperature range [t1, t2]. If so, proceed to step 10); if not, proceed to step 9); 9) using circulating cooling water (203) in the hydrogen production station to dissipate heat until the electrolyte working temperature meets the working temperature range [t1, t2]; 10) The electrolyte that meets the temperature requirements flows back to the first liquid storage tank (106) and the second liquid storage tank (107).

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