Multi-generation hydrogen production system and method based on wind-solar-photo-thermal complementation

Abstract

In the system, a wind-solar power generation unit is connected with a hydrogen production and poly-generation module, and a photo-thermal heat supply unit is connected with a cascade fused salt heat storage module; the cascade fused salt heat storage module comprises a hot fused salt storage tank and a cold fused salt storage tank; the hydrogen production and poly-generation module comprises an SOEC unit, a thermoelectric ammonia / alcohol synthesis unit and a thermoelectric circulation unit, and the cascade molten salt heat storage module provides high-temperature molten salt for the thermoelectric circulation unit to drive power generation, provides high-temperature molten salt for the SOEC unit to produce hydrogen and provides high-temperature, medium-temperature and / or low-temperature molten salt for the thermoelectric ammonia / alcohol synthesis unit to supply unit energy. The hot molten salt returns to the cold molten salt storage tank after completing the set heat supply target and reaching the set temperature of the cold molten salt storage tank; the output end of the thermoelectric circulating unit is connected with the SOEC unit and the thermoelectric ammonia / alcohol synthesis unit to supply power; the input end of the power storage module is connected with the wind-solar power generation module and the thermoelectric cycle unit, and the output end is connected with the hydrogen production and poly-generation module.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of renewable energy integration and energy storage technology, in particular to a multi-generation hydrogen production system and method based on wind-solar-photothermal complementation. BACKGROUND

[0002] With the large-scale application of renewable energy and the rapid development of hydrogen energy industry, wind-solar power generation coupled with high-temperature electrolysis of water and electric-thermal multi-generation technology has become an important path to realize zero-carbon energy transformation. However, wind-solar power generation is intermittent and highly volatile, and direct hydrogen production and multi-generation require large-scale energy storage, resulting in high system cost, which needs to be coupled with photothermal heating to maintain stability and compensation. Traditional molten salt heat storage systems mostly use single molten salt systems (such as nitrate), which have the problems of unreasonable heat energy configuration and high-grade heat energy degradation. The multi-generation system (such as hydrogen production, ammonia / synthetic alcohol synthesis) has not been deeply coupled with the characteristics of molten salt cascade heat storage utilization for multi-stage demand of heat energy and electricity, resulting in waste of high-grade energy. In view of the above problems, it is urgent to develop a wind-solar-photothermal complementary multi-generation hydrogen production system, to clarify the operation and multi-grade molten salt cascade configuration optimization method of the system, to realize the efficient integration of wind-solar power generation, photothermal power station, electrolytic hydrogen production and thermochemical synthesis, and to improve the economic efficiency and energy conversion efficiency of the system.

[0003] The information disclosed in the background section merely serves to enhance the understanding of the background of the present application, and therefore can contain information that is not prior art known to those of ordinary skill in the art. SUMMARY

[0004] In view of the deficiencies or shortcomings of the prior art, a multi-generation hydrogen production system and method based on wind-solar-photothermal complementation are provided, which uses molten salt to supply heat energy and follows the strategy of "wind-solar power generation first, thermal power recycling, and storage peak shaving" for electricity supply, with the goal of minimizing the investment (cost) cost of molten salt procurement-tank equipment, matching molten salt grades with user demand according to temperature level, and clarifying the multi-grade molten salt configuration method.

[0005] The purpose of the present application is achieved by the following technical solutions.

[0006] A multi-generation hydrogen production system based on wind-solar-photothermal complementation includes an energy input module, a cascade molten salt heat storage module, a hydrogen production and multi-generation module, and a storage module; wherein,

[0007] The energy input module includes a wind-solar power generation unit and a photothermal heating unit, the wind-solar power generation unit is connected to the hydrogen production and multi-generation module, and the photothermal heating unit is connected to the cascade molten salt heat storage module;

[0008] The stepped molten salt heat storage module includes a hot molten salt storage tank and a cold molten salt storage tank, the hot molten salt storage tank includes a high-temperature hot molten salt storage tank, a medium-temperature hot molten salt storage tank and a low-temperature hot molten salt storage tank, which respectively supply high-temperature, medium-temperature and low-temperature hot molten salts to the hydrogen production and poly-generation module to drive power generation, hydrogen production and ammonia / alcohol synthesis, and the cold molten salt storage tank includes a high-temperature cold molten salt storage tank, a medium-temperature cold molten salt storage tank and a low-temperature cold molten salt storage tank, the input ends of which are high-temperature, medium-temperature and low-temperature cold molten salts from the hydrogen production and poly-generation module, which complete the heat supply target and reach the set temperature of the cold molten salt storage tank.

[0009] In the hydrogen production system based on wind-solar-photothermal complementary poly-generation, the hydrogen production and poly-generation module includes an SOEC unit, a thermal power synthesis ammonia / alcohol unit and a thermal power cycle unit, the stepped molten salt heat storage module provides high-temperature molten salt to the thermal power cycle unit to drive power generation, provides high-temperature molten salt to the SOEC unit for hydrogen production, and provides high-temperature, medium-temperature and / or low-temperature molten salt to the thermal power synthesis ammonia / alcohol unit for unit energy supply, and the output end of the thermal power cycle unit is connected to the SOEC unit and the thermal power synthesis ammonia / alcohol unit to supply power to them.

[0010] The power storage module has input ends connected to the wind-solar power generation module and the thermal power cycle unit, and an output end connected to the hydrogen production and poly-generation module.

[0011] In the hydrogen production system based on wind-solar-photothermal complementary poly-generation, the heat of the hydrogen production and poly-generation module is supplied by the stepped molten salt heat storage module, and the power supply of the hydrogen production and poly-generation module is sequentially supplied by the wind-solar power generation unit, the thermal power cycle unit and the power storage module.

[0012] In the hydrogen production system based on wind-solar-photothermal complementary poly-generation, the heat of the hydrogen production and poly-generation module is completely supplied by the stepped molten salt heat storage module, the heat supply follows the principle of energy quality stepped utilization (high-quality high use, low-quality low use), and the multi-grade molten salt heat energy of the stepped molten salt heat storage module is directionally distributed according to the user-side heat sink temperature threshold.

[0013] In the hydrogen production system based on wind-solar-photothermal complementary poly-generation, the high-temperature molten salt used by the thermal power cycle unit is high-temperature molten salt heated by the photothermal heat supply unit, which is used to drive the steam turbine to generate power, and the residual heat molten salt is sent to the hydrogen production and poly-generation module to continue to participate in heat utilization.

[0014] In the hydrogen production system based on wind-solar-photothermal complementary poly-generation, the heat required by the SOEC unit is completely provided by high-temperature molten salt, and the thermal power synthesis ammonia / alcohol unit selectively accepts high-temperature, medium-temperature or low-temperature molten salt for energy supply to meet the demand for heat energy in different reaction stages.

[0015] The operation method of the hydrogen production system based on wind-solar-photothermal complementary poly-generation includes:

[0016] If the power generation of the wind-solar power generation unit is greater than the power consumption of the hydrogen production and poly-generation module, the wind-solar power generation unit alone supplies power to the hydrogen production and poly-generation module, and the excess power of the wind-solar power generation unit and the thermal-electric circulation unit is stored in the power storage module;

[0017] If the power generation of the wind-solar power generation unit is less than the power consumption of the hydrogen production and poly-generation module, the power generation of the thermal-electric circulation unit is greater than the remaining power consumption demand of the hydrogen production and poly-generation module, the wind-solar power generation unit and the thermal-electric circulation unit simultaneously supply power to the hydrogen production and poly-generation module, and the excess power of the thermal-electric circulation unit is stored in the power storage module;

[0018] If the total power supply of the wind-solar power generation unit and the thermal-electric circulation unit is less than the power consumption of the hydrogen production and poly-generation module, the wind-solar power generation unit, the thermal-electric circulation unit and the power storage module simultaneously supply power to the hydrogen production and poly-generation module;

[0019] If the total power supply of the wind-solar power generation unit, the thermal-electric circulation unit and the power storage module is less than the power consumption of the hydrogen production and poly-generation module, the production of the hydrogen production and poly-generation module is reduced.

[0020] In the operation method, all heat loads are provided by the cascade molten salt heat storage module.

[0021] The multi-molten salt cascade configuration method of the wind-solar-light-thermal complementary poly-generation hydrogen production system comprises the following steps:

[0022] S100: Obtain the heat demand of the user side and the heat sink temperature, establish the matching rules of the high-temperature, medium-temperature and low-temperature multi-grade molten salt and the load and temperature of the user side heat sink, and the load and temperature matching rules are,

[0023]

[0024] Wherein, represents the mass flow rate of the i-th high-temperature, medium-temperature and low-temperature molten salt; C P,MSi represents the specific heat capacity of the molten salt; T in,MSi and T out,MSi represents the temperature of the i-th molten salt into and out of the heat exchanger; Q USERj represents the j-type user heat load; ΔT min The heat exchanger is set to have a minimum heat transfer temperature difference;

[0025] S200: Calculate the total heat of the multi-grade molten salt, construct the corresponding molten salt procurement cost model based on the load and temperature matching rules, and then construct the molten salt storage tank equipment investment cost (cost) model;

[0026] S300: Taking the minimization of the total cost of molten salt procurement and storage tank equipment investment as the objective function, a high-temperature, medium-temperature and low-temperature molten salt ratio scheme is generated, which improves the system heat utilization efficiency while reducing the construction investment cost of the molten salt heat storage module.

[0027] The configuration method, wherein the total heat of the multi-grade molten salt is:

[0028]

[0029] Q S represents the total heat supply of the molten salt; Q MSi represents the heat charging rate of the molten salt i per unit time; t k,MSi represents the heat charging time of the molten salt i in the k period; CP MSi represents the heat capacity flow rate of the molten salt i; M represents the number of heat charging periods; and N represents the number of molten salts. and represent the highest and lowest temperatures of the molten salt;

[0030] The molten salt procurement cost model is represented as:

[0031]

[0032] wherein C MS represents the molten salt procurement cost required by the system; N represents the number of molten salts; PC MSi represents the price of the molten salt i; Q MSi represents the heat charging rate of the molten salt i per unit time; C P,MSi represents the specific heat capacity of the molten salt; and represent the highest and lowest temperatures of the molten salt; and DIT represents the daylight time length.

[0033] The molten salt storage tank equipment investment cost (cost) model is:

[0034]

[0035] wherein C TES represents the molten salt storage tank equipment investment cost (cost); a HST and b CST represent the molten salt storage tank cost coefficients; N represents the number of molten salts; Q MSi represents the heat charging rate of the molten salt i per unit time; C P,MSi represents the specific heat capacity of the molten salt; and represent the highest and lowest temperatures of the molten salt; and p MSi represents the density of the molten salt; DIT represents the daylight time length; and 24 represents the daily time length.

[0036] The configuration method, wherein the objective function is:

[0037] min C total =C MS +C TES

[0038] wherein Ctotal represents the total cost of molten salt procurement and storage tank equipment investment; C MS represents the required molten salt procurement cost of the system; C TES represents the molten salt storage tank equipment investment cost (cost).

[0039] Compared with the prior art, the present application has the beneficial effects that: the present application effectively compensates for the intermittent large fluctuation and high energy storage requirement of photovoltaic power generation by using a photo-thermal power station, and the use of a cascade molten salt storage tank meets the demand for efficient energy storage. The present disclosure clearly defines a multi-molten salt cascade configuration method of a wind-solar-photo-thermal complementary multi-generation hydrogen production system, which can reduce the construction investment cost of the cascade molten salt heat storage module as much as possible while efficiently storing heat.

[0040] The description is only a summary of the technical solutions of the present application, in order to make the technical means of the present application clearer and more understandable, to the extent that a person skilled in the art can implement according to the content of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following will be illustrated by specific embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0041] Various other advantages and benefits of the present application will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included solely for purposes of illustrating the preferred embodiments and are not to be construed as a limitation of the present application. It should be readily understood that the drawings depicted are only some embodiments of the present application and that any other drawings, which are the same as those depicted, can be derived from the depicted drawings by a person of ordinary skill in the art without paying creative labor. Moreover, the same reference numerals are used throughout the drawings to represent the same components.

[0042] In the drawings:

[0043] Figure 1 is a structural schematic diagram of a wind-solar-photo-thermal complementary multi-generation hydrogen production system provided by one embodiment of the present disclosure;

[0044] Wherein: 100, energy input module; 110, wind-solar power generation unit; 120, photo-thermal heat supply unit; 200, cascade molten salt heat storage module; 210, hot molten salt storage tank; 211, high-temperature hot molten salt storage tank; 212, medium-temperature hot molten salt storage tank; 213, low-temperature hot molten salt storage tank; 220, cold molten salt storage tank; 221, high-temperature cold molten salt storage tank; 222, medium-temperature cold molten salt storage tank; 223, low-temperature cold molten salt storage tank; 300, hydrogen production and multi-generation module; 310, SOEC unit; 320, thermal-electric synthesis ammonia / alcohol unit; 330, thermal-electric cycle unit; 400, electricity storage module;

[0045] Figure 2is a flow diagram of a power supply process of a multi-generation hydrogen production system based on wind-solar-thermal complementation provided by another embodiment of the present disclosure.

[0046] Figure 3 is a flow diagram of a multi-salt cascade configuration process of a multi-generation hydrogen production system based on wind-solar-thermal complementation provided by another embodiment of the present disclosure.

[0047] The present application will be further explained with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0048] Specific embodiments of the present application will be described in greater detail below with reference to the accompanying drawings. Although specific embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application can be accurately conveyed to those skilled in the art.

[0049] It should be noted that certain terms are used in the specification and claims to refer to certain components. Those skilled in the art will understand that the same component can be referred to by different terms. The specification and claims should not be construed as limited by the terms used to refer to the components, but rather by the functional differences between the components. As used throughout the specification and claims, "comprise" or "include" is an open term, which should be interpreted to mean "comprise but not limited to." The subsequent description describes preferred embodiments of the present application for the purpose of illustrating the general principles of the present application, and not to limit the scope of the present application. The scope of the present application is defined by the appended claims.

[0050] To facilitate understanding of the embodiments of the present application, the following will be further explained and described with reference to the accompanying drawings in several specific embodiments, and each drawing does not constitute a limitation on the embodiments of the present application.

[0051] For better understanding, as shown in Figures 1 to 3 A multi-generation hydrogen production system based on wind-solar-thermal complementation includes an energy input module 100, a cascade molten salt heat storage module 200, a hydrogen production and multi-generation module 300, and a power storage module 400; wherein,

[0052] The energy input module 100 includes a wind-solar power generation unit 110 and a solar thermal heating unit 120, the wind-solar power generation unit 110 is connected to the hydrogen production and multi-generation module 300, and the solar thermal heating unit 120 is connected to the cascade molten salt heat storage module 200;

[0053] The stepped molten salt heat storage module 200 includes a hot molten salt storage tank 210 and a cold molten salt storage tank 220, the hot molten salt storage tank 210 includes a high-temperature hot molten salt storage tank 211, a medium-temperature hot molten salt storage tank 212 and a low-temperature hot molten salt storage tank 213, which respectively supply high-temperature, medium-temperature and low-temperature hot molten salts to the hydrogen production and poly-generation module 300 to drive power generation, hydrogen production and ammonia / alcohol synthesis, and the cold molten salt storage tank 220 includes a high-temperature cold molten salt storage tank 221, a medium-temperature cold molten salt storage tank 222 and a low-temperature cold molten salt storage tank 223, the input ends of which are respectively high-temperature, medium-temperature and low-temperature cold molten salts from the hydrogen production and poly-generation module 300 which have completed the heat supply target and reached the set temperature of the cold molten salt storage tank;

[0054] The hydrogen production and poly-generation module 300 includes a SOEC unit 310, a thermal power ammonia / alcohol synthesis unit 320 and a thermal power cycle unit 330, the stepped molten salt heat storage module 200 supplies high-temperature molten salt to the thermal power cycle unit 330 to drive power generation, supplies high-temperature molten salt to the SOEC unit 310 for hydrogen production, and supplies high-temperature, medium-temperature and / or low-temperature molten salt to the thermal power ammonia / alcohol synthesis unit 320 for unit energy supply, and the output end of the thermal power cycle unit 330 is connected to the SOEC unit 310 and the thermal power ammonia / alcohol synthesis unit 320 to supply power to them;

[0055] The power storage module 400 has input ends connected to the wind-solar power generation module 110 and the thermal power cycle unit 330 respectively, and an output end connected to the hydrogen production and poly-generation module 300.

[0056] In the preferred embodiment of the wind-solar-photothermal complementary based poly-generation hydrogen production system, the heat of the hydrogen production and poly-generation module 300 is supplied by the stepped molten salt heat storage module 200, and the power supply of the hydrogen production and poly-generation module 300 is sequentially supplied by the wind-solar power generation unit 110, the thermal power cycle unit 330 and the power storage module 400.

[0057] In the preferred embodiment of the wind-solar-photothermal complementary based poly-generation hydrogen production system, the heat of the hydrogen production and poly-generation module 300 is completely supplied by the stepped molten salt heat storage module 200, and the heat supply follows the principle of energy quality stepped utilization (high-quality high-use, low-quality low-use), realizing the directional distribution of the multi-grade molten salt heat energy of the stepped molten salt heat storage module 200 according to the user side heat sink temperature threshold.

[0058] In the preferred embodiment of the wind-solar-photothermal complementary based poly-generation hydrogen production system, the high-temperature molten salt used by the thermal power cycle unit 330 is high-temperature molten salt heated by the photothermal heat supply unit, which is used to drive the steam turbine to generate power, and the residual heat molten salt is sent to the hydrogen production and poly-generation module for further heat utilization.

[0059] In the preferred embodiment of the wind-solar-photothermal complementary multi-generation hydrogen production system, the heat required by the SOEC unit 310 is completely provided by high-temperature molten salt, and the thermo-electric synthesis ammonia / alcohol unit 320 selectively receives high-temperature, medium-temperature or low-temperature molten salt to meet the heat energy requirements of different reaction stages.

[0060] The operation method of the wind-solar-photothermal complementary multi-generation hydrogen production system comprises the following steps:

[0061] If the power generation of the wind-solar power generation unit 110 is greater than the power consumption of the hydrogen production and multi-generation module 300, the wind-solar power generation unit 110 alone supplies power to the hydrogen production and multi-generation module 300, and the excess power of the wind-solar power generation unit 110 and the thermo-electric cycle unit 330 is stored in the power storage module 400.

[0062] If the power generation of the wind-solar power generation unit 110 is less than the power consumption of the hydrogen production and multi-generation module 300, the power generation of the thermo-electric cycle unit 330 is greater than the remaining power consumption demand of the hydrogen production and multi-generation module 300, the wind-solar power generation unit 110 and the thermo-electric cycle unit 330 simultaneously supply power to the hydrogen production and multi-generation module 300, and the excess power of the thermo-electric cycle unit 330 is stored in the power storage module 400.

[0063] If the total power supply of the wind-solar power generation unit 110 and the thermo-electric cycle unit 330 is less than the power consumption of the hydrogen production and multi-generation module 300, the wind-solar power generation unit 110, the thermo-electric cycle unit 330 and the power storage module 400 simultaneously supply power to the hydrogen production and multi-generation module 300.

[0064] If the total power supply of the wind-solar power generation unit 110, the thermo-electric cycle unit 330 and the power storage module 400 is less than the power consumption of the hydrogen production and multi-generation module 300, the yield of the hydrogen production and multi-generation module 300 is reduced.

[0065] In the preferred embodiment of the operation method, all heat loads are provided by the cascade molten salt heat storage module.

[0066] The multi-molten salt cascade configuration method of the wind-solar-photothermal complementary multi-generation hydrogen production system comprises the following steps:

[0067] S100: Obtain the heat demand of the user side and the heat sink temperature, and establish a load and temperature matching rule of the multi-grade molten salt of high temperature, medium temperature and low temperature and the user side heat sink, and the load and temperature matching rule is,

[0068]

[0069] Wherein, represents the mass flow rate of the i-th high-temperature, medium-temperature and low-temperature molten salt; C P,MSi represents the specific heat capacity of the molten salt; T in,MSi and T out,MSi represents the temperature of the i-th molten salt into and out of the heat exchanger; QUSERj represents the jth user heat load; ΔT min The heat exchanger sets the minimum heat transfer temperature difference;

[0070] S200: Calculate the total heat of multi-grade molten salt, construct a corresponding molten salt procurement cost model based on the load and temperature level matching rule, and then construct a molten salt storage tank equipment investment cost (cost) model;

[0071] S300: Taking the total cost of molten salt procurement and storage tank equipment investment as the objective function, a high-temperature, medium-temperature and low-temperature molten salt ratio scheme is generated to improve the system heat utilization efficiency and reduce the construction investment cost of the molten salt heat storage module.

[0072] In the preferred embodiment of the configuration method, the total heat of the multi-grade molten salt is:

[0073]

[0074] Wherein, Q S represents the total heat supply of molten salt; Q MSi represents the heat charging rate of molten salt i per unit time; t k,MSi represents the heat charging time of molten salt i in k period; CP MSi represents the heat capacity flow rate of molten salt i; M represents the number of heat charging periods; N represents the number of molten salts; and represents the highest and lowest temperature of molten salt;

[0075] The molten salt procurement cost model is represented as:

[0076]

[0077] Wherein, C MS represents the molten salt procurement cost required by the system; N represents the number of molten salts; PC MSi represents the price of molten salt i; Q MSi represents the heat charging rate of molten salt i per unit time; C P,MSi represents the specific heat capacity of molten salt; and represents the highest and lowest temperature of molten salt; DIT represents the daylight duration; 24 represents the daily duration;

[0078] The molten salt storage tank equipment investment cost (cost) model is:

[0079]

[0080] Wherein, C TES represents the molten salt storage tank equipment investment cost (cost); a HST and b CST represent the molten salt storage tank cost coefficient; N represents the number of molten salts; Q MSirepresents the heat charging rate of molten salt per unit time; C P,MSi represents the specific heat capacity of molten salt; and represents the highest and lowest temperature of molten salt; p MSi represents the density of molten salt; DIT represents the light duration; 24 represents the daily duration;

[0081] In the preferred embodiment of the configuration method, the objective function is:

[0082] min C total =C MS +C TES

[0083] wherein C total represents the total cost of molten salt procurement and storage tank equipment investment; C MS represents the molten salt procurement cost required by the system; C TES represents the molten salt storage tank equipment investment cost (cost).

[0084] In one embodiment, the co-production system comprises an energy input module, a cascade molten salt thermal storage module, a hydrogen production and poly-generation module, and an electricity storage module; the energy input module is connected to the cascade molten salt thermal storage module, the hydrogen production and poly-generation module, and the electricity storage module, respectively; the cascade molten salt thermal storage module outputs high-temperature, medium-temperature, and low-temperature molten salt to the hydrogen production and poly-generation unit to drive power generation, hydrogen production, and ammonia / alcohol synthesis; the hydrogen production and poly-generation module comprises an SOEC hydrogen production unit and an electric-thermal ammonia / alcohol synthesis unit; the electricity storage module is connected to a wind-solar power generation module and a thermoelectric cycle unit, and delivers electricity to the hydrogen production and poly-generation module. The operation method comprises a heat supply and power supply strategy of the hydrogen production and poly-generation module. The multi-grade molten salt configuration method is based on the temperature, procurement, and storage cost differences of molten salt, follows the principle of cascade utilization of energy and quality (high-grade high-use, low-grade low-use), and determines the ratio of different grades of molten salt to minimize the above-mentioned costs, so as to reduce the construction investment cost of the molten salt thermal storage module and improve the comprehensive energy efficiency of the system.

[0085] Embodiment 1:

[0086] As shown in Figure 1 , a wind-solar-photothermal complementary based multi-generation hydrogen production system comprises an energy input module 100, a cascade molten salt thermal storage module 200, a hydrogen production and poly-generation module 300, and an electricity storage module 400;

[0087] The energy input module 100 comprises a wind-solar power generation unit 110 and a photothermal heat supply unit 120; the wind-solar power generation unit 110 is connected to the hydrogen production and poly-generation module 300, and the photothermal heat supply unit 120 is connected to the cascade molten salt thermal storage module 200;

[0088] The stepped molten salt heat storage module 200 includes a hot molten salt storage tank 210 and a cold molten salt storage tank 220, the hot molten salt storage tank 210 includes a high-temperature hot molten salt storage tank 211, a medium-temperature hot molten salt storage tank 212 and a low-temperature hot molten salt storage tank 213, and the cold molten salt storage tank 220 includes a high-temperature cold molten salt storage tank 221, a medium-temperature cold molten salt storage tank 222 and a low-temperature cold molten salt storage tank 223, and the input ends are respectively high-temperature, medium-temperature and low-temperature cold molten salts from the hydrogen production and poly-generation module 300, which complete the predetermined heat supply target and reach the set temperature of the cold molten salt storage tank;

[0089] The hydrogen production and poly-generation module 300 includes an SOEC unit 310, a thermal power synthetic ammonia / alcohol unit 320 and a thermal power circulation unit 330, the stepped molten salt heat storage module 200 provides high-temperature molten salt to the thermal power circulation unit 330 for power generation, provides high-temperature molten salt to the SOEC unit 310 for hydrogen production, and provides high-temperature, medium-temperature and / or low-temperature molten salt to the thermal power synthetic ammonia / alcohol unit 320 for unit energy, and the output end of the thermal power circulation unit 330 is connected to the SOEC unit 310 and the thermal power synthetic ammonia / alcohol unit 320 to supply power to them.

[0090] The input end of the electricity storage module 400 is respectively the wind-solar power generation module 110 and the thermal power circulation unit 330, and the output end of the electricity storage module 400 is the hydrogen production and poly-generation module 300.

[0091] Embodiment 2:

[0092] This embodiment is based on the embodiment 1, and introduces a running method of a wind-solar-light-thermal complementary based poly-generation hydrogen production system, the running method of the wind-solar-light-thermal complementary based poly-generation hydrogen production system includes heat supply and power supply of the hydrogen production and poly-generation module 300.

[0093] The heat of the hydrogen production and poly-generation module 300 is supplied by the stepped molten salt heat storage module 200.

[0094] The power supply of the hydrogen production and poly-generation module 300 is sequentially supplied according to the wind-solar power generation unit 110, the thermal power circulation unit 330 and the electricity storage module 400.

[0095] Specifically, the heat demand of the hydrogen production and poly-generation module 300 can be completely supplied by the stepped molten salt heat storage module 200, and no other heat source is needed, the heat supply follows the principle of energy quality stepped utilization (high-quality high use, low-quality low use), and the multi-grade molten salt heat energy of the stepped molten salt heat storage module (200) is directionally distributed according to the user side heat sink temperature threshold.

[0096] Specifically, the power supply of the hydrogen production and poly-generation module 300 is as shown in Figure 2 The flow is as follows:

[0097] S100: If the power generation of the wind-solar power generation unit 110 is greater than the power consumption of the hydrogen production and poly-generation module 300, the wind-solar power generation unit 110 alone supplies power to the hydrogen production and poly-generation module 300, and the excess power of the wind-solar power generation unit 110 and the thermal-electric circulation unit 330 is stored in the power storage module 400;

[0098] S200: If the power generation of the wind-solar power generation unit 110 is less than the power consumption of the hydrogen production and poly-generation module 300, the power generation of the thermal-electric circulation unit 330 is greater than the remaining power consumption demand of the hydrogen production and poly-generation module 300, the wind-solar power generation unit 110 and the thermal-electric circulation unit 330 simultaneously supply power to the hydrogen production and poly-generation module 300, and the excess power of the thermal-electric circulation unit 330 is stored in the power storage module 400;

[0099] S300: If the total power supply of the wind-solar power generation unit 110 and the thermal-electric circulation unit 330 is less than the power consumption of the hydrogen production and poly-generation module 300, the wind-solar power generation unit 110, the thermal-electric circulation unit 330 and the power storage module 400 simultaneously supply power to the hydrogen production and poly-generation module 300;

[0100] S400: If the total power supply of the wind-solar power generation unit 110, the thermal-electric circulation unit 330 and the power storage module 400 is less than the power consumption of the hydrogen production and poly-generation module 300, the yield of the hydrogen production and poly-generation module 300 is reduced.

[0101] Embodiment 3:

[0102] This embodiment is based on embodiments 1 and 2, and introduces a multi-salt cascade configuration method of a wind-solar-thermal complementary multi-generation hydrogen production system. As shown in Figure 3 , the configuration strategy is as follows:

[0103] S100: Obtain the heat demand of the user side and the heat sink temperature, and determine the load and temperature matching rules of the multi-grade (high temperature / medium temperature / low temperature) molten salt and the user side heat sink;

[0104] In this step, the multi-grade (high temperature / medium temperature / low temperature) molten salt and its corresponding properties are as shown in Table 1:

[0105] Table 1 Multi-grade (high temperature / medium temperature / low temperature) molten salt and its corresponding properties

[0106]

[0107] In this step, the load and temperature matching rules of the multi-grade (high temperature / medium temperature / low temperature) molten salt and the user side heat sink can be expressed as:

[0108]

[0109] Wherein, represents the mass flow rate of the i-th stage (high temperature / medium temperature / low temperature) molten salt; C P,MSi represents the specific heat capacity of the molten salt; T in,MSi and T out,MSi represents the temperature of the i-th stage molten salt entering and leaving the heat exchanger; Q USERj represents the heat load of the j-th type of user; ΔT min The heat exchanger is set to have a minimum heat transfer temperature difference.

[0110] S200: Determine the total heat of the multi-grade molten salt, based on the heat of the energy using side and the user side heat sink and the temperature matching rule of the multi-grade (high temperature / medium temperature / low temperature) molten salt, construct a corresponding molten salt procurement cost model, and then construct a molten salt storage tank equipment investment cost (cost) model;

[0111] In this step, the total heat of the multi-grade molten salt can be represented as:

[0112]

[0113] Wherein, Q S represents the total heat supply of the molten salt; Q MSi represents the heat charging rate of the molten salt i per unit time; t k,MSi represents the heat charging time of the molten salt i in the k period; CP MSi represents the heat capacity flow rate of the molten salt i; M represents the number of heat charging periods; N represents the number of molten salts; and represents the highest and lowest temperatures of the molten salt.

[0114] The molten salt procurement cost model can be represented as:

[0115]

[0116] Wherein, C MS represents the molten salt procurement cost required by the system; N represents the number of molten salts; PC MSi represents the price of the molten salt i; Q MSi represents the heat charging rate of the molten salt i per unit time; C P,MSi represents the specific heat capacity of the molten salt; and represents the highest and lowest temperatures of the molten salt; DIT represents the length of daylight; 24 represents the length of each day;

[0117] The molten salt storage tank equipment investment cost (cost) model can be represented as:

[0118]

[0119] Wherein, C TES represents the molten salt storage tank equipment investment cost (cost); a HST and bCST represents the molten salt storage tank cost coefficient; N represents the molten salt quantity; Q MSi represents the unit time heat charging quantity of the molten salt i; C P,MSi represents the specific heat capacity of the molten salt; and represents the highest and lowest temperature of the molten salt; p MSi represents the density of the molten salt; DIT represents the light duration; 24 represents the daily duration;

[0120] S300: generating a high / medium / low temperature molten salt matching scheme with the objective of minimizing the total cost of molten salt procurement and storage tank equipment investment.

[0121] In this step, the objective of minimizing the total cost of molten salt procurement and storage tank equipment investment can be represented as:

[0122] min C total =C MS +C TES (5)

[0123] wherein C total represents the total cost of molten salt procurement and storage tank equipment investment; C MS represents the required molten salt procurement cost of the system; C TES represents the molten salt storage tank equipment investment cost (cost).

[0124] Next, the molten salt configuration of a certain molten salt cascade utilization hydrogen production and poly-generation system based on wind-solar-photothermal complementation is optimized by the existing method and the scheme described in the present disclosure, to further illustrate the technical effects of the present scheme.

[0125] A certain 100MW load photothermal driven molten salt heat supply thermochemical water decomposition hydrogen production system selects NaCl-MgCl2(58-42%, mol) as a single molten salt, and the corresponding cascade molten salt heat storage module construction investment cost (including molten salt procurement cost and storage tank equipment investment cost) is 15.35M$;

[0126] The molten salt configuration is optimized by using the multi-molten salt cascade configuration method of the poly-generation hydrogen production system based on wind-solar-photothermal complementation described in the present disclosure, and the data obtained are as follows:

[0127] In step S100, the user side heat demand and heat sink temperature are obtained, and the parameters are shown in Table 2. Based on this, the load and temperature matching rules of multi-product (high temperature / medium temperature / low temperature) molten salt and user side heat sink are determined, which can be represented as:

[0128]

[0129] Table 2 User side heat demand and heat sink temperature

[0130]

[0131] In step S200, the total heat of the multi-grade molten salt is 100 MW, and based on the energy consumption side heat and the user side heat sink, the load and temperature level matching rules of the multi-grade (high temperature / medium temperature / low temperature) molten salt are used to construct a corresponding molten salt procurement cost model, and then a molten salt storage tank equipment investment cost (cost) model is constructed;

[0132] In step S300, the multi-grade molten salt ratio scheme for minimizing the total cost of molten salt procurement and storage tank equipment investment is shown in Table 3. The corresponding minimum gradient molten salt heat storage module construction investment cost is 14.38M$, which is 6.32% lower than before optimization

[0133] Table 3 High / medium / low temperature molten salt ratio scheme for minimizing the total cost of molten salt procurement and storage tank equipment investment

[0134] Fused salt type Supply temperature / °C Target temperature / °C Load / MW Ratio NaCl-MgCl2(58-42%, mol) 715 500 50 64％ NaNO3-KNO3 (64-36%, mol) 565 290 50 36％

[0135] Therefore, by using the scheme of the present disclosure to optimize the molten salt configuration, the gradient molten salt heat storage module construction investment cost can be minimized by 6.32%, and the system NaCl-MgCl2(58-42%, mol) molten salt ratio is 100% before optimization, and the NaCl-MgCl2(58-42%, mol) and NaNO3-KNO3(64-36%, mol) molten salts are 64% and 36%, respectively, after optimization.

[0136] The application is a complementary integrated system of wind-solar power generation and photo-thermal heating. The wind-solar power generation unit and the photo-thermal heating unit are jointly connected to the system to form an energy input module. Clean electricity is provided by wind-solar power generation to reduce carbon emissions. The photo-thermal power station serves as a stable heat source, which can smooth out wind-solar fluctuations and ensure continuous operation of the system. The system realizes dual-channel energy supply of "electricity + heat" to improve system flexibility and stability. It makes up for the defects of single wind-solar power supply, such as high energy storage demand and high cost, enhances economic efficiency, and realizes hierarchical molten salt storage. The hierarchical molten salt storage module adopts multi-grade molten salt storage tanks to realize hierarchical storage and on-demand supply of molten salt at different temperature levels. It meets the demand of SOEC water electrolysis, ammonia / alcohol synthesis and other processes for heat at different temperature levels. It avoids the degradation of high-grade heat energy and improves energy utilization efficiency. It has strong heat storage capacity and can adapt to load fluctuations caused by intermittent wind and solar energy. It supports energy storage peak shaving of photo-thermal power stations, extends the use time of heat energy, and improves the energy utilization rate of the system. The heat and power cycle generation unit driven by molten salt uses high-temperature molten salt to drive a steam turbine to generate electricity, forming a heat and power cycle subsystem. The stored heat energy is converted into electrical energy to participate in system power regulation. It supplements power supply when wind and solar energy is insufficient, improves system power supply reliability, realizes hierarchical recycling of heat energy, and improves overall energy conversion efficiency. It cooperates with the electricity storage module to optimize the system energy scheduling strategy. The SOEC water electrolysis unit is powered by high-temperature molten salt and uses a solid oxide electrolysis cell (SOEC) to maintain the reaction temperature with high-temperature molten salt as the heat source. SOEC can operate at high temperatures, significantly improving electrolysis efficiency. The heat energy comes from the molten salt storage system, eliminating the need for additional heating devices and reducing costs. It improves the efficiency of green hydrogen production and promotes the development of the hydrogen energy industry. Combined with wind-solar power generation, it realizes zero-carbon hydrogen production. The heat and power synthesis ammonia / alcohol unit flexibly accepts multi-temperature molten salt power supply. According to the requirements of the synthesis process, it selectively receives high-temperature, medium-temperature or low-temperature molten salt power supply. It adapts to the heat demand of various chemical processes, improves system applicability, realizes precise matching of heat energy, avoids energy waste, improves the utilization rate of the molten salt system and the overall revenue of the system, and promotes the downstream application of green hydrogen, such as green ammonia, methanol and other chemical production. The electricity storage module participates in power peak shaving and buffering. The electricity storage module (such as lithium batteries, super capacitors, etc.) is connected to wind-solar power generation and heat and power cycle generation. It smooths out wind-solar power fluctuations and relieves the pressure on the power grid. It discharges to support critical load operation when there is a power shortage. It improves the system's independent operation capability and power supply reliability. It realizes a multi-level power dispatching strategy of "wind-solar priority, heat and power supplement, and electricity storage peak shaving". The multi-molten salt hierarchical configuration optimization method constructs a molten salt procurement cost model and a storage tank equipment investment cost model to determine the optimal molten salt ratio through optimization algorithms. It realizes precise matching of molten salt types, quantities and user demand, reduces the total cost of molten salt procurement and storage tank construction, improves heat energy utilization efficiency, and reduces redundant design. It provides a scientific configuration basis for large-scale photo-thermal storage systems.Based on the temperature level matching of molten salt supply and demand relationship modeling, the required flow and temperature difference of each level of molten salt are accurately calculated to ensure that the heat load meets the requirements; avoid the decline of heat transfer efficiency of heat exchanger or excessive heat loss; support the optimization of multi-molten salt cascade configuration, improve the controllability and safety of the system; provide mathematical basis for dynamic regulation of molten salt system. The total heat supply of molten salt and the modeling of storage tank capacity, the energy supply capacity of molten salt thermal storage system is quantified; support system capacity planning and economic evaluation; provide data support for molten salt tank selection and layout; realize the closed-loop optimization of system design and operation stage. The optimization strategy with the minimum total cost as the target optimizes the total cost of molten salt procurement and storage tank equipment investment as the objective function. Considering the initial investment and operating cost, the economic efficiency of the system is improved; provide theoretical support for project feasibility study and investment decision; realize the dual goals of "technically feasible + economically optimal"; suitable for the design and promotion of various types of solar thermal storage systems.

[0137] The above describes the basic principles of the present application in combination with specific embodiments, but it should be noted that the advantages, advantages, effects, etc. mentioned in the present application are only examples and not limitations, and these advantages, advantages, effects, etc. cannot be considered as the must-have of each embodiment of the present application. In addition, the above specific details are only for the purpose of example and understanding, and are not limited to the above specific details to realize the present application.

[0138] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although the above has discussed a plurality of example aspects and embodiments, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations.

Claims

1. A combined wind-solar-solar-thermal hydrogen production system, characterized in that, It includes an energy input module (100), a cascade molten salt thermal storage module (200), a hydrogen production and polygeneration module (300), and an energy storage module (400); among which, The energy input module (100) includes a wind and solar power generation unit (110) and a solar thermal heating unit (120). The wind and solar power generation unit (110) is connected to the hydrogen production and polygeneration module (300), and the solar thermal heating unit (120) is connected to the cascade molten salt thermal storage module (200). The cascade molten salt thermal energy storage module (200) includes a hot molten salt storage tank (210) and a cold molten salt storage tank (220), wherein, The molten salt storage tank (210) includes a high-temperature molten salt storage tank (211), a medium-temperature molten salt storage tank (212), and a low-temperature molten salt storage tank (213), which respectively supply high-temperature, medium-temperature, and low-temperature molten salts to the hydrogen production and polygeneration module (300) to drive power generation, hydrogen production, and ammonia / methanol synthesis. The molten salt storage tank (220) includes a high-temperature molten salt storage tank (221), a medium-temperature molten salt storage tank (222), and a low-temperature molten salt storage tank (223). The input ends are high-temperature, medium-temperature, and low-temperature molten salts from the hydrogen production and polygeneration module (300) that have achieved the predetermined heating target and reached the set temperature of the molten salt storage tank.

2. The combined wind-solar-solar-thermal hydrogen production system as described in claim 1, characterized in that, Preferred, The hydrogen production and polygeneration module (300) includes an SOEC unit (310), a thermoelectric ammonia / methanol synthesis unit (320), and a thermoelectric cycle unit (330). The cascaded molten salt thermal storage module (200) provides high-temperature molten salt to the thermoelectric cycle unit (330) for power generation, provides high-temperature molten salt to the SOEC unit (310) for hydrogen production, and provides high-temperature, medium-temperature, and / or low-temperature molten salt to the thermoelectric ammonia / methanol synthesis unit (320) for energy use. The output of the thermoelectric cycle unit (330) is connected to the SOEC unit (310) and the thermoelectric ammonia / alcohol synthesis unit (320) to supply power to them; The energy storage module (400) has its input terminals connected to the wind and solar power generation module (110) and the thermoelectric cycle unit (330), respectively, and its output terminal connected to the hydrogen production and polygeneration module (300).

3. The combined wind-solar-solar-thermal hydrogen production system as described in claim 1, characterized in that, The heat of the hydrogen production and polygeneration module (300) is supplied by the cascade molten salt thermal storage module (200), and the power supply of the hydrogen production and polygeneration module (300) is supplied in the order of wind and solar power generation unit (110), thermal power cycle unit (330) and energy storage module (400).

4. The combined wind-solar-solar-thermal hydrogen production system as described in claim 1, characterized in that, The heat of the hydrogen production and polygeneration module (300) is entirely supplied by the cascade molten salt thermal energy storage module (200). The heat supply follows the principle of energy quality cascade utilization (high quality for high use, low quality for low use), so that the multi-grade molten salt thermal energy of the cascade molten salt thermal energy storage module (200) is directionally distributed according to the user-side heat sink temperature threshold.

5. The combined wind-solar-solar-thermal hydrogen production system as described in claim 1, characterized in that, The high-temperature molten salt used in the thermoelectric cycle unit (330) is a high-temperature molten salt heated by the solar thermal heating unit, which is used to drive the steam turbine to generate electricity, and the waste heat molten salt is sent to the hydrogen production and multi-generation module to continue to participate in heat utilization.

6. The operation method of the combined wind-solar-solar-thermal hydrogen production system according to any one of claims 1-5, characterized in that, It includes: If the power generation of the wind and solar power generation unit (110) is greater than the power consumption of the hydrogen production and polygeneration module (300), the wind and solar power generation unit (110) supplies power to the hydrogen production and polygeneration module (300) separately, and the excess power of the wind and solar power generation unit (110) and the thermoelectric cycle unit (330) is stored in the energy storage module (400). If the power generation of the wind and solar power generation unit (110) is less than the power consumption of the hydrogen production and combined heat and power generation module (300), and the power generation of the thermoelectric cycle unit (330) is greater than the remaining power consumption of the hydrogen production and combined heat and power generation module (300), the wind and solar power generation unit (110) and the thermoelectric cycle unit (330) simultaneously supply power to the hydrogen production and combined heat and power generation module (300), and the excess power of the thermoelectric cycle unit (330) is stored in the energy storage module (400); If the total power supply of the wind and solar power generation unit (110) and the thermoelectric cycle unit (330) is less than the power consumption of the hydrogen production and polygeneration module (300), the wind and solar power generation unit (110), the thermoelectric cycle unit (330) and the energy storage module (400) will simultaneously supply power to the hydrogen production and polygeneration module (300). If the total power output of the wind and solar power generation unit (110), the thermoelectric cycle unit (330) and the energy storage module (400) is less than the power consumption of the hydrogen production and polygeneration module (300), the output of the hydrogen production and polygeneration module (300) will be reduced.

7. The operating method as described in claim 6, characterized in that, All heat loads are provided by cascaded molten salt thermal storage modules.

8. The method for configuring multiple molten salt stages in a combined wind-solar-solar-thermal hydrogen production system as described in any one of claims 1-5, characterized in that, It includes: S100: Obtain user-side heat demand and heat sink temperature, and establish load and temperature matching rules between high-temperature, medium-temperature, and low-temperature multi-grade molten salts and user-side heat sinks. The load and temperature matching rules are as follows: in, C represents the mass flow rate of the molten salt at the i-th stage (high temperature, medium temperature, low temperature); P,MSi T represents the specific heat capacity of molten salt; in,MSi and T out,MSi Q represents the temperature of the i-th stage molten salt entering and exiting the heat exchanger; USERj Represents the heat load of user type j; ΔT min The heat exchanger is set to a minimum heat transfer temperature difference; S200: Calculate the total heat of multi-grade molten salt, construct the corresponding molten salt procurement cost model based on the load and temperature matching rules, and then construct the molten salt storage tank equipment investment cost model; S300: With the objective function of minimizing the total investment cost of molten salt procurement and storage tank equipment, it generates high-temperature, medium-temperature, and low-temperature molten salt ratio schemes to improve the system's heat utilization efficiency while reducing the investment cost of molten salt thermal storage modules.

9. The configuration method as described in claim 8, characterized in that, The total calorific value of the multi-grade molten salt is: Among them, Q S Q represents the total heat output of the molten salt; MSi t represents the amount of heat charged per unit time in molten salt i; k,MSi Indicates the charging time of molten salt i during time period k; CP MSi M represents the heat flow rate of molten salt i; N represents the number of charging periods; and N represents the quantity of molten salt. and Indicates the highest and lowest temperatures of the molten salt; The molten salt procurement cost model is expressed as follows: Among them, C MS PC represents the molten salt procurement cost required by the system; N represents the quantity of molten salt; MSi Q represents the price of molten salt i; MSi C represents the amount of heat charged per unit time in molten salt i; P,MSi This indicates the specific heat capacity of molten salt; and Indicates the highest and lowest temperatures of the molten salt; DIT indicates the duration of light exposure; 24 indicates the duration of a day; The investment cost model for molten salt storage tank equipment is as follows: Among them, C TES This indicates the investment cost of molten salt storage tank equipment; a HST and b CST Indicates the cost coefficient of the molten salt storage tank; N represents the quantity of molten salt; Q MSi C represents the amount of heat charged per unit time in molten salt i; P,MSi This indicates the specific heat capacity of molten salt; and Indicates the highest and lowest temperatures of the molten salt; ρ MS i represents molten salt density; DIT represents illumination duration; 24 represents daily duration.

10. The configuration method as described in claim 9, characterized in that, The objective function is: my C total =C MS +C TES , Among them, C total This represents the total cost of molten salt procurement and storage tank equipment investment; C MS Indicates the cost of molten salt required by the system; C TES This indicates the investment cost of molten salt storage tank equipment.

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