A solar-based microalgae gas production energy conversion system

Abstract

The application discloses a solar-based microalgae gas production energy conversion system, comprising a photovoltaic system and a microalgae gas production system; the microalgae gas production system is suitable for microalgae culture, hydrothermal pretreatment and anaerobic fermentation process; when the light intensity is sufficient, the photovoltaic system is suitable for supplying power and heat to the microalgae gas production system and storing the residual electricity; when the light intensity is insufficient, the photovoltaic system is suitable for supplying power to the microalgae gas production system through the residual electricity. The application has the beneficial effects that: through efficient utilization of solar light, heat and photovoltaic, the application can realize low energy consumption input or even zero energy consumption input and high energy efficiency. Meanwhile, the equipment of the microalgae gas production process section can be highly concentrated, and the application has the advantages of small land occupation and low initial equipment investment.

Description

Technical Field

[0001] This application relates to the field of biotechnology, and in particular to a solar-powered microalgae gas production energy conversion system. Background Technology

[0002] Algae, as a third-generation biofuel, has many advantages over the first two generations of biofuels (food crops and non-food crops), including not competing with humans for food, a short growth cycle, and high oil production efficiency. The entire microalgae biogas production process includes microalgae cultivation, hydrothermal pretreatment, and anaerobic fermentation. Existing equipment or systems for microalgae biogas production have the following technical shortcomings:

[0003] (1) The three processes of microalgae cultivation, hydrothermal pretreatment and anaerobic fermentation correspond to independent energy supply systems, which results in high initial investment in the overall equipment, large footprint, and waste of resources.

[0004] (2) The energy of the three processes corresponding to the independent energy supply system has not been utilized in a cascade manner, resulting in a large amount of waste heat and poor operating economy;

[0005] (3) Open photobioreactor systems lack good temperature control measures and it is difficult to achieve efficient mass and energy transfer, resulting in low microalgae culture capacity. Summary of the Invention

[0006] One objective of this application is to provide a microalgae gas production energy conversion system that can solve at least one of the defects of the aforementioned background technology.

[0007] To achieve at least one of the above objectives, the technical solution adopted in this application is as follows: a solar-based microalgae gas production energy conversion system, comprising a photovoltaic system and a microalgae gas production system; the microalgae gas production system is suitable for carrying out microalgae cultivation, hydrothermal pretreatment, and anaerobic fermentation processes; when the light intensity is sufficient, the photovoltaic system is suitable for supplying power and heat to the microalgae gas production system and storing the surplus electricity; when the light intensity is insufficient, the photovoltaic system is suitable for supplying power to the microalgae gas production system using the surplus electricity.

[0008] Preferably, the photovoltaic system includes a photovoltaic panel array and a first battery; when the light intensity is sufficient, the photovoltaic panel array is adapted to receive sunlight and supply power to the microalgae gas production system, and to store excess electricity in the first battery; when the light intensity is insufficient, the first battery is adapted to supply power to the microalgae gas production system.

[0009] Preferably, the photovoltaic panel is made of a light-transmitting material; the photovoltaic system also includes a light-transmitting pipe, which is laid flat below the photovoltaic panel and connected to the microalgae gas production system. The light-transmitting pipe is adapted to convert solar energy into heat energy and supply heat to the microalgae gas production system.

[0010] Preferably, the solar-based microalgae gas production energy conversion system further includes an ORC system and a temperature control system; the ORC system is adapted to supply power to the temperature control system and to supply heat to the microalgae gas production system using the waste heat generated; the temperature control system is also adapted to supply heat to the microalgae gas production system, so that the microalgae gas production system can use the waste heat of the ORC system and the temperature control system to control the temperature to be consistent with the process requirements.

[0011] Preferably, the ORC system includes a steam circulation system, a steam turbine, and a second battery. When the light intensity is sufficient, the steam circulation system is adapted to generate high-temperature steam to drive the steam turbine to generate electricity. The electrical energy generated by the steam turbine is adapted to supply power to the temperature control system or be stored in the second battery. At the same time, the waste heat of the high-temperature steam generated by the steam circulation system is adapted to heat the microalgae gas production system. When the light intensity is insufficient, the steam circulation system stops working, and at this time, the second battery is adapted to supply power to the temperature control system.

[0012] Preferably, the temperature control system includes a compressor, a heat storage module, and a cold storage module connected in series in a cycle; the compressor is adapted to compress the circulating working fluid into a high-temperature, high-pressure gas through the power supply of the ORC system, and the high-temperature, high-pressure gas flows sequentially through the heat storage module and the cold storage module, so that the heat storage module and the cold storage module maintain heat storage and cold storage respectively; the heat storage module is adapted to regulate the temperature of the microalgae gas production system, and the cold storage module is adapted to regulate the temperature of the microalgae gas production system.

[0013] Preferably, the microalgae gas production system includes an open photobioreactor system, a hydrothermal system, and an anaerobic fermentation system; the open photobioreactor system is adapted to carry out microalgae cultivation through power supply from the photovoltaic system and heat supply from the temperature control system; the hydrothermal system is adapted to carry out hydrothermal pretreatment through heat supply from the photovoltaic system and heat supply from the ORC system; and the anaerobic fermentation system is adapted to carry out anaerobic fermentation through heat supply from the ORC system.

[0014] Preferably, the open photobioreactor system includes a photobioreactor tank, a photoelectric module, a suspended radiation pipe network, and a second working fluid pump; the photobioreactor tank is used to hold microalgae, and the photoelectric module and the suspended radiation pipe network are both installed inside the photobioreactor tank; the photoelectric module is adapted to be powered by the photovoltaic system; when the light intensity is sufficient, the photoelectric module only rotates and stirs; when the light intensity is insufficient, the photoelectric module emits light while rotating and stirring; the suspended radiation pipe network is adapted to be connected to the temperature control system through the second working fluid pump, so that the suspended radiation pipe network controls the temperature of the photobioreactor tank to meet the process temperature requirements through the temperature control system.

[0015] Preferably, the hydrothermal system includes a hydrothermal tank, a microalgae liquid pipeline, and a third working fluid pump. The hydrothermal tank contains a high-temperature heat storage medium. The hydrothermal tank is connected to the photovoltaic system via the third working fluid pump, so that the photovoltaic system can keep the high-temperature heat storage medium in the hydrothermal tank warm. At the same time, the working fluid of the ORC system carrying waste heat is suitable to pass through the hydrothermal tank, thereby keeping the high-temperature heat storage medium in the hydrothermal tank warm as well. The microalgae liquid pipeline is installed in the hydrothermal tank, so that the microalgae produced in the open photobioreactor system, after being collected and processed, flows into the microalgae liquid pipeline through the microalgae liquid inlet to absorb the heat of the high-temperature heat storage medium for hydrothermal reaction, thereby obtaining water-soluble organic matter.

[0016] Preferably, the anaerobic fermentation system includes an anaerobic fermenter containing a mesophilic heat storage medium. Water-soluble organic matter is suitable for entering the anaerobic fermenter through the inlet, thereby absorbing heat from the mesophilic heat storage medium to maintain the anaerobic fermentation temperature. The biogas produced is collected and output through the biogas outlet of the anaerobic fermenter. The working fluid of the ORC system carrying waste heat continues to pass through the anaerobic fermenter after flowing through the hydrothermal system, so that the working fluid of the ORC system can keep the mesophilic heat storage medium in the anaerobic fermenter warm.

[0017] Compared with the prior art, the beneficial effects of this application are as follows:

[0018] This application achieves low or even zero energy input through the efficient utilization of solar thermal and photovoltaic energy, resulting in high energy efficiency. Simultaneously, it allows for a high degree of integration of equipment across various microalgae gas production processes, offering advantages such as small footprint and low initial investment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the photovoltaic system in this invention.

[0021] Figure 3 This is a schematic diagram of the ORC system in this invention.

[0022] Figure 4 This is a schematic diagram of the temperature control system in this invention.

[0023] Figure 5 This is a schematic diagram of the open bioreactor system in this invention.

[0024] Figure 6 This is a schematic diagram of the hydrothermal system in this invention.

[0025] Figure 7 This is a schematic diagram of the anaerobic fermentation system in this invention.

[0026] Figure 8 This is a schematic diagram of the specific connection structure of the present invention.

[0027] Figure 9 This is a schematic diagram of the suspended radiant pipe network in this invention.

[0028] In the diagram: Photovoltaic system 100, photovoltaic panel assembly 110, light-transmitting pipe 120, first battery 130, ORC system 200, first working fluid pump 210, solar collector 220, steam turbine 230, first condenser 240, subcooling pipe 250, second battery 260, temperature control system 300, compressor 310, heat storage box 320, second condenser 330, cold storage box 340, evaporator 350, expansion valve 360, microalgae gas generation system 400, open photobioreactor The system includes: a photobioreactor 411, a motor 412, a spiral light component 413, a suspended radiation pipe network 414, a first temperature sensor 415, a light sensor 416, a second working fluid pump 417, a first shut-off valve 418, a second shut-off valve 419, a hydrothermal system 420, a hydrothermal tank 421, a microalgae liquid pipeline 422, a third working fluid pump 423, a second temperature sensor 424, an anaerobic fermentation system 430, an anaerobic fermenter 431, and a third temperature sensor 432. Detailed Implementation

[0029] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0030] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0031] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0032] One preferred embodiment of this application, such as Figures 1 to 9 As shown, a solar-based microalgae gas production energy conversion system includes a photovoltaic system 100 and a microalgae gas production system 400. The microalgae gas production system 400 can perform processes such as microalgae cultivation, hydrothermal pretreatment, and anaerobic fermentation to realize the entire energy conversion process of microalgae gas production. The photovoltaic system 100 can receive sunlight to generate electricity and heat. When the light intensity is sufficient, the photovoltaic system 100 can use the generated electricity to power the microalgae gas production system 400, and simultaneously use the generated heat to heat the microalgae gas production system 400. Furthermore, the electricity generated by the photovoltaic system 100 under sufficient light intensity generally exceeds the electricity demand of the microalgae gas production system 400, and the photovoltaic system 100 can also store the surplus electricity. Therefore, when the light intensity is insufficient, the photovoltaic system 100 can use the surplus electricity to power the microalgae gas production system 400. Compared with traditional microalgae gas production energy conversion methods, this application can achieve low energy input or even zero energy input through the efficient utilization of solar thermal and photovoltaic energy, resulting in high efficiency and energy saving.

[0033] Understandably, this application has two operating modes depending on weather conditions. The first is a standard illumination mode when there is sufficient light intensity, which is generally operated during sunny days. The second is a standard illumination mode when there is insufficient light intensity, which is generally operated at night or on cloudy days. In the first mode, the photovoltaic system 100 can receive light energy and convert it into electrical and thermal energy to supply power and heat to the microalgae gas production system 400, and can also store excess electricity. In the second mode, the photovoltaic system 100 cannot convert light energy, and in this case, the excess electricity stored in the photovoltaic system 100 can be used to supply power to the microalgae gas production system 400.

[0034] In this embodiment, as Figure 1 , Figure 2 and Figure 8 As shown, the photovoltaic system 100 includes a photovoltaic panel assembly 110 and a first battery 130. The output terminal of the photovoltaic panel assembly 110 can be electrically connected to both the first battery 130 and the microalgae gas generation system 400. Thus, when the light intensity is sufficient, the photovoltaic panel assembly 110 can receive sunlight to convert it into electrical energy and supply the converted electrical energy to the microalgae gas generation system 400, while storing some surplus electricity in the first battery 130; when the light intensity is insufficient, the first battery 130 can supply power to the microalgae gas generation system 400 using the stored surplus electricity.

[0035] Meanwhile, the photovoltaic system 100 also includes a light-transmitting pipe 120, which can be connected to the microalgae gas production system 400. When the light intensity is sufficient, the light-transmitting pipe 120 can convert solar energy into heat energy and supply heat to the microalgae gas production system 400.

[0036] It should be understood that the operation of the light-transmitting pipe 120 is similar to that of a solar water heater. In order to further reduce the footprint of the photovoltaic system 100, the photovoltaic panel assembly 110 can be made of a light-transmitting material, so that the light-transmitting pipe 120 can be laid flat under the photovoltaic panel assembly 110, so that sunlight can pass through the photovoltaic panel assembly 110 and shine on the light-transmitting pipe 120, thereby realizing photoelectric and photothermal conversion respectively, while improving the structural compactness of the photovoltaic system 100.

[0037] It should also be noted that among the three processes in microalgae gas production, the microalgae cultivation process is the most sensitive to temperature changes, and the suitable temperature for microalgae cultivation is mostly within the room temperature range. Therefore, the allowable range of environmental temperature variation in the microalgae cultivation process is relatively small, generally within 10℃. In contrast, the hydrothermal pretreatment process and the anaerobic fermentation process require process temperatures much higher than room temperature. Therefore, the heat generated by the light-transmitting pipe 120 in the photovoltaic system 100 is not convenient for heating the microalgae cultivation process; it can only be used to heat the hydrothermal pretreatment process or the anaerobic fermentation process.

[0038] One embodiment of this application, such as Figure 1 and Figure 8 As shown, the solar-powered microalgae gas production energy conversion system also includes an ORC system 200 and a temperature control system 300. The ORC system 200 can supply power to the temperature control system 300 and use the waste heat generated to heat the microalgae gas production system 400. The temperature control system 300 can also supply heat to the microalgae gas production system 400, so that the microalgae gas production system 400 can utilize the waste heat from the ORC system 200 and the temperature control system 300 to control the temperature to be consistent with the process requirements.

[0039] Understandably, because the microalgae cultivation process is highly sensitive to temperature changes, a separate temperature control system 300 is required to control the temperature of the microalgae cultivation process. Meanwhile, in the second operating mode, the photovoltaic system 100 cannot supply heat to the hydrothermal pretreatment process or the anaerobic fermentation process; therefore, the waste heat generated by the ORC system 200 during the power supply to the temperature control system 300 can be used to heat both the hydrothermal pretreatment process and the anaerobic fermentation process, respectively, to ensure that the temperatures of both processes meet the process temperature requirements in any operating mode.

[0040] Meanwhile, the ORC system 200 and the temperature control system 300 can be basic thermodynamic cycle systems or variations of similar thermodynamic cycle systems.

[0041] Generally, the temperature requirements for hydrothermal pretreatment are higher than those for anaerobic fermentation. Therefore, the waste heat generated by the ORC system 200 can be utilized in a cascade manner, meaning the waste heat from the ORC system 200 first undergoes hydrothermal pretreatment and then anaerobic fermentation. Simultaneously, the heat generated by the light-transmitting pipe 120 in the photovoltaic system 100 can be preferably supplied to the hydrothermal pretreatment process to further ensure that the temperatures of both the hydrothermal pretreatment and anaerobic fermentation processes meet the process temperature requirements. This achieves cascaded energy utilization while avoiding resource waste.

[0042] In this embodiment, as Figure 1 , Figure 3 and Figure 8 As shown, the ORC system 200 includes a steam circulation system, a steam turbine 230, and a second battery 260. When the steam circulation system is operating, it generates high-temperature steam to drive the steam turbine 230 to generate electricity. The electrical energy generated by the steam turbine 230 can be used to power the temperature control system 300 or stored in the second battery 260. Simultaneously, the waste heat from the high-temperature steam generated by the steam circulation system can supply heat to the microalgae gas production system 400. When the steam circulation system is not operating, the second battery 260 can use its stored electrical energy to power the temperature control system 300.

[0043] Understandably, to fully utilize solar energy, the steam cycle system can use solar energy to convert the circulating working fluid into high-temperature steam. Therefore, in the first operating mode, due to sufficient sunlight, the steam cycle system can start normally, converting the circulating working fluid into high-temperature steam to drive the turbine 230 to generate electricity. In the second operating mode, due to insufficient sunlight, the steam cycle system does not start. In this case, the temperature control system 300 can be powered by the electrical energy stored in the second battery 260 by the turbine 230 in the first operating mode.

[0044] Specifically, such as Figure 3 and Figure 8 As shown, the steam circulation system includes a first working fluid pump 210, a solar collector 220, and a first condenser 240. The output end of the first working fluid pump 210 is connected to the input end of the solar collector 220, the output end of the solar collector 220 is connected to the input end of the steam turbine 230, the steam output end of the steam turbine 230 can be connected to the input end of the first condenser 240, and the first condenser 240 is located in the hydrothermal pretreatment process. The output end of the first condenser 240 can be connected to the input end of the subcooling pipeline 250 located in the anaerobic fermentation process, and the output end of the subcooling pipeline 250 can be connected to the input end of the first working fluid pump 210.

[0045] In the first operating mode, the first working fluid pump 210 starts, delivering the circulating working fluid to the solar collector 220. The solar collector 220 can be a trough-type solar collector. The solar collector 220 uses the high temperature generated by solar energy to evaporate the circulating working fluid into high-temperature steam, so that the turbine 230 can generate electricity under the action of the high-temperature steam. If the temperature control system 300 needs to work at this time, the electrical energy generated by the turbine 230 directly supplies power to the temperature control system 300. If the temperature control system 300 does not need to work at this time, the electrical energy generated by the turbine 230 is stored in the second battery 260. Then, the high-temperature steam becomes high-temperature exhaust steam and enters the first condenser 240 to condense and release heat to the hydrothermal pretreatment process, so that the high-temperature exhaust steam becomes a medium-high temperature liquid. Subsequently, the medium-high temperature liquid enters the subcooling pipe 250 and further releases the residual heat to the anaerobic fermentation process, and finally becomes a low-temperature liquid and returns to the first working fluid pump 210 to form a cycle.

[0046] When the second working mode is in operation, the steam circulation system is not started. If the temperature control system 300 needs to work, it can be powered by the second battery 260.

[0047] In this embodiment, as Figure 4 and Figure 8 As shown, the temperature control system 300 includes a compressor 310, a heat storage module, and a cold storage module connected in series. The compressor 310, powered by the ORC system 200, compresses the circulating working fluid into a high-temperature, high-pressure gas. This high-temperature, high-pressure gas flows sequentially through the heat storage module and the cold storage module, forming a low-temperature, low-pressure gas that returns to the compressor 310, thus maintaining heat storage and cold storage in the heat storage module and cold storage module, respectively. The heat storage module regulates the temperature of the microalgae gas production system 400, while the cold storage module regulates the temperature of the microalgae gas production system 400.

[0048] Specifically, such as Figure 4 and Figure 8As shown, the temperature control system 300 also includes an expansion valve 360, an evaporator 350, and a second condenser 330; the heat storage module includes a heat storage tank 320, and the cold storage module includes a cold storage tank 340. In the temperature control system 300, the compressor 310, heat storage tank 320, second condenser 330, expansion valve 360, cold storage tank 340, and evaporator 350 are connected in series via pipelines. The circulating working fluid, under the compression of the compressor 310, becomes a high-temperature, high-pressure gas that flows into the heat storage tank 320 to release heat, thus maintaining the temperature of the medium-temperature molten heat storage medium within the heat storage tank 320. Subsequently, the circulating working fluid enters the second condenser 330, where it condenses and releases excess heat, becoming a high-pressure, medium-temperature liquid. After being throttled and depressurized by the expansion valve 360, it flows into the cold storage tank 340 and releases cold energy to maintain the temperature of the cold storage medium in the cold storage tank 340. The circulating working fluid then enters the evaporator 350 to release excess cooling capacity. Finally, the circulating working fluid becomes a low-temperature, low-pressure gas and flows into the inlet of the compressor 310 to form a cycle. Both the heat storage box 320 and the cold storage box 340 are connected to the microalgae cultivation process, so the heat storage box 320 and the cold storage box 340 can respectively heat up or cool down the microalgae cultivation process.

[0049] It is understood that the structure and working principle of the second condenser 330 and the evaporator 350 are well known to those skilled in the art, and therefore will not be described in detail here; common structures include air-cooled condensers and air-cooled evaporators.

[0050] One embodiment of this application, such as Figure 1 and Figure 8 As shown, the microalgae gas production system 400 includes an open photobioreactor system 410, a hydrothermal system 420, and an anaerobic fermentation system 430. The open photobioreactor system 410 utilizes power from the photovoltaic system 100 and heat from the temperature control system 300 for microalgae cultivation. The hydrothermal system 420 utilizes heat from the photovoltaic system 100 and the ORC system 200 for hydrothermal pretreatment. The anaerobic fermentation system 430 utilizes heat from the ORC system 200 for anaerobic fermentation.

[0051] It is understandable that the microalgae gas generation system 400, photovoltaic system 100, ORC system 200 and temperature control system 300 are centrally located, thereby achieving a high degree of equipment concentration in each process section of microalgae gas generation, which has the advantages of small footprint and low initial equipment investment.

[0052] In this embodiment, as Figure 5 and Figure 8As shown, the open photobioreactor system 410 includes a photobioreactor tank 411, a photoelectric module, a suspended radiant pipe network 414, and a second working fluid pump 417. The photobioreactor tank 411 is used to hold and cultivate microalgae. The suspended radiant pipe network 414 is installed inside the photobioreactor tank 411 and can be connected to a temperature control system 300 via the second working fluid pump 417, allowing the temperature control system 300 to control the temperature of the culture solution within the photobioreactor tank 411 to meet process temperature requirements. The photoelectric module is also installed inside the photobioreactor tank 411 and can be powered by a photovoltaic system 100. When the light intensity is sufficient, the photoelectric module only rotates and stirs, which shortens the energy and mass transfer distance in the culture solution within the photobioreactor tank 411 and disturbs the fluid and light source coupling within the photobioreactor tank 411, thereby enhancing the heat transfer efficiency of light energy and heat transfer within the suspended radiant pipe network 414, and effectively increasing the yield of microalgae. When the light intensity is insufficient, the light module emits light while rotating and stirring, thus ensuring the light intensity required for microalgae growth.

[0053] In this embodiment, as Figure 5 and Figure 8 As shown, the light module includes a motor 412 and a spiral light element 413. Multiple spiral light elements 413 can be set and evenly distributed within the photobioreactor 411. The motor 412 is mounted on top of the photobioreactor 411, and its output is connected to each spiral light element 413 via a transmission structure. The photovoltaic system 100 can power the motor 412 and the spiral light elements 413. In the first operating mode, due to sufficient light and the open structure of the photobioreactor 411, there is no need to supplement the microalgae cultivation. At this time, the electrical energy from the photovoltaic panel assembly 110 is supplied to the motor 412 to drive the spiral light elements 413 to rotate, while the remaining electricity is stored in the first battery 130. When the second working mode is in operation, the photovoltaic panel group 110 does not work due to insufficient light. Then the first battery 130 can supply power to the motor 412 to drive the spiral light element 413 to rotate. At the same time, the first battery 130 can also supply power to the spiral light element 413 so that the spiral light element 413 can provide supplementary light by emitting light.

[0054] Understandably, the blades of the helical light element 413 can take various forms, such as full-surface or ribbon.

[0055] In this embodiment, as Figure 5 , Figure 8 and Figure 9As shown, the suspended radiation pipe network 414 can be arranged in a multi-segment zigzag or U-shape and set on the upper part of the photobioreactor 411 to ensure that the temperature regulation range of the suspended radiation pipe network 414 is closer to the suspension position of the microalgae.

[0056] It should be understood that there are multiple ways to connect the suspended radiant pipe network 414 to the heat storage tank 320 and the cold storage tank 340; one preferred connection method is as follows: the suspended radiant pipe network 414 is provided with two ports, the first port of which can be connected to the input end of the second working fluid pump 417, the output end of the second working fluid pump 417 is connected to the input end of the cold storage pipeline located in the cold storage tank 340 through the first shut-off valve 418, and the output end of the cold storage pipeline can be connected to the second port of the suspended radiant pipe network 414. At the same time, the output end of the second working fluid pump 417 can also be connected to the input end of the heat storage pipeline located in the heat storage tank 320 through the second shut-off valve 419, and the output end of the heat storage pipeline can also be connected to the second port of the suspended radiant pipe network 414.

[0057] When the temperature of the photobioreactor 411 is lower than the lower limit of the set temperature range, the first shut-off valve 418 is closed and the second shut-off valve 419 is opened. The circulating working fluid in the suspended radiation pipe network 414 can then flow through the second shut-off valve 419 under the action of the second working fluid pump 417 and enter the heat storage pipe network in the heat storage tank 320. At this time, the circulating working fluid can absorb the heat from the medium-temperature molten heat storage medium in the heat storage tank 320 and then flow back into the suspended radiation pipe network 414, thereby increasing the temperature inside the photobioreactor 411. When the temperature of the photobioreactor 411 is higher than the upper limit of the set temperature range, the second shut-off valve 419 is closed and the first shut-off valve 418 is opened. The circulating working fluid can then flow through the first shut-off valve 418 under the action of the second working fluid pump 417 and enter the cold storage pipe network in the cold storage tank 340. At this time, the circulating working fluid can absorb the cold energy from the cold storage medium and then flow back into the suspended radiation pipe network 414, thereby decreasing the temperature inside the photobioreactor 411.

[0058] Specifically, such as Figure 5 and Figure 8As shown, a first temperature sensor 415 and a light sensor 416 are respectively installed in the photobioreactor 411. The first temperature sensor 415 detects the temperature inside the photobioreactor 411 and sends the result to the temperature control system 300 and the second working fluid pump 417 to ensure that the temperature control system 300 and the second working fluid pump 417 can start in a timely manner, thereby ensuring that the temperature inside the photobioreactor 411 meets the process temperature requirements. The light sensor 416 detects the light intensity inside the photobioreactor 411 and sends the result to the spiral light element 413. This ensures that the spiral light element 413 does not emit light when there is sufficient light, and emits light to supplement illumination when there is insufficient light, thus ensuring that the light intensity inside the photobioreactor 411 always meets the needs of microalgae growth.

[0059] It should be understood that, through the photovoltaic system 100 and ORC system 200-driven temperature control system 300 installed on the top of the open photobioreactor system 410, the suspended radiation pipe network 414 and spiral light component 413 installed in the photobioreactor tank 411, the system of this application can ensure that, while possessing the advantages of convenient and low-energy consumption of open microalgae cultivation, it also has the functions of strong light shading, temperature and light intensity control that are only available in closed photobioreactor systems.

[0060] In this embodiment, as Figure 6 and Figure 8 As shown, the hydrothermal system 420 includes a hydrothermal tank 421, a microalgae liquid pipeline 422, and a third working fluid pump 423. The hydrothermal tank 421 contains a high-temperature heat storage medium. The hydrothermal tank 421 is connected to the photovoltaic system 100 via the third working fluid pump 423, allowing the photovoltaic system 100 to insulate the high-temperature heat storage medium in the hydrothermal tank 421. Simultaneously, the working fluid carrying waste heat from the ORC system 200 can pass through the hydrothermal tank 421, further insulating the high-temperature heat storage medium within it. The microalgae liquid pipeline 422 is installed within the hydrothermal tank 421, allowing the microalgae produced in the open photobioreactor system 410 to be collected and processed, then flow into the microalgae liquid pipeline 422 through the microalgae liquid inlet to absorb heat from the high-temperature heat storage medium for hydrothermal reaction, thereby obtaining water-soluble organic matter.

[0061] Specifically, such as Figure 6 and Figure 8As shown, the first condenser 240 in the ORC system 200 is installed inside the hydrothermal tank 421, and the piping of the first condenser 240 has a multi-segment zigzag structure and is evenly distributed along the depth direction of the hydrothermal tank 421. A heating pipe is installed on the upper part of the hydrothermal tank 421, and this heating pipe is connected to the light-transmitting pipe 120 in the photovoltaic system 100 via a third working fluid pump 423. When the first operating mode is activated, the photovoltaic system 100 can circulate the heat-generating working fluid generated by the light-transmitting pipe 120 into the heating pipe located on the upper part of the hydrothermal tank 421, thereby heating and maintaining the temperature of the hydrothermal tank 421. Meanwhile, the steam circulation system can introduce high-temperature exhaust steam into the first condenser 240 to further heat and insulate the hydrothermal tank 421; thus, in the first working mode, the hydrothermal pretreatment process of microalgae basically does not require additional energy consumption. The waste heat of the ORC system 200 and the heating of the photovoltaic system 100 can basically ensure the normal operation of the hydrothermal pretreatment process, thereby effectively reducing energy consumption.

[0062] It is understandable that the temperature of the hydrothermal bath 421 can be monitored in real time by a second temperature sensor 424 to ensure that the temperature within the hydrothermal bath 421 remains within the required process temperature range. Specifically, in the first operating mode, if the second temperature sensor 424 detects an excessively high temperature, the heating supply to the light-transmitting pipe 120 and / or the ORC system 200 can be shut off. In any operating mode, if the second temperature sensor 424 detects an excessively low temperature, an additional heating module can be activated to heat the hydrothermal bath 421.

[0063] In this embodiment, as Figure 7 and Figure 8 As shown, the anaerobic fermentation system 430 includes an anaerobic fermenter 431, which contains a mesophilic heat storage medium. Water-soluble organic matter can enter the anaerobic fermenter 431 through the inlet, thereby absorbing heat from the mesophilic heat storage medium to maintain the anaerobic fermentation temperature. The biogas produced can be collected and output through the biogas outlet of the anaerobic fermenter 431. The working fluid of the ORC system 200, carrying waste heat, continues to pass through the anaerobic fermenter 431 after flowing through the hydrothermal system 420, so that the working fluid of the ORC system 200 can keep the mesophilic heat storage medium in the anaerobic fermenter 431 warm.

[0064] Specifically, the subcooling pipe 250 in the ORC system 200 is distributed in a multi-segment zigzag structure in the anaerobic digester 431. Thus, the medium-high temperature liquid after passing through the first condenser 240 in the steam circulation system can enter the subcooling pipe 250, and further release the waste heat to be absorbed by the medium-temperature heat storage medium in the anaerobic digester 431, so as to achieve heating and heat preservation of the anaerobic digester 431.

[0065] Understandably, the temperature of the anaerobic fermenter 431 can be monitored in real time by a third temperature sensor 432 to ensure that the temperature inside the anaerobic fermenter 431 remains within the required process temperature range. Specifically, in the first operating mode, if the third temperature sensor 432 detects an excessively high temperature, the heating supply from the ORC system 200 can be shut off, and an additional conventional cooling method can be activated to lower the temperature. In any operating mode, if the third temperature sensor 432 detects an excessively low temperature, an additional heating module can be activated promptly to heat the anaerobic fermenter 431.

[0066] It should be understood that by setting up high-temperature heat storage media, medium-temperature heat storage media, and cold storage media, not only can the intermittent and discontinuous drawbacks of solar energy be avoided, but also the energy can be utilized in a cascade manner.

[0067] To facilitate understanding, the working process of the system in this application will be described below.

[0068] (1) When the light intensity is sufficient to achieve the light source intensity standard mode;

[0069] The steam circulation system of ORC system 200 is started. The circulating working fluid, under the action of the first working fluid pump 210, evaporates in the solar collector 220, absorbing heat to form high-temperature steam. Then, the steam turbine 230 generates electricity using this high-temperature steam. The high-temperature, high-pressure steam then becomes high-temperature exhaust steam and is condensed in the first condenser 240 located in the hydrothermal tank 421. The heat released by the first condenser 240 heats and insulates the high-temperature heat storage medium in the hydrothermal tank 421, ensuring the normal operation of the hydrothermal pretreatment process. Subsequently, the high-temperature exhaust steam becomes a medium-high temperature liquid and enters the subcooling pipe 250 located in the anaerobic fermenter 431, further releasing waste heat to the medium-temperature heat storage medium in the anaerobic fermenter 431 for heating and insulation, ensuring the normal operation of the anaerobic fermentation process. Finally, the medium-high temperature liquid becomes a low-temperature liquid and returns to the first working fluid pump 210 to form a cycle.

[0070] At this point, the temperature control system 300 is activated if the open photobioreactor system 410 needs to be adjusted, otherwise the temperature control system 300 will not be activated.

[0071] If the temperature control system 300 is started, the compressor 310 can be started by the power supply of the steam turbine 230, thereby compressing the circulating working fluid into a high-temperature, high-pressure gas that flows into the heat storage tank 320 to heat and maintain the temperature of the medium-temperature molten heat storage medium. Then, the circulating working fluid passes through the second condenser 330 and the expansion valve 360 ​​before entering the cold storage tank 340 for evaporation and heat absorption, thereby maintaining the temperature of the cold storage medium in the cold storage tank 340. Subsequently, the circulating working fluid enters the evaporator 350 to release excess cooling capacity, and finally, the circulating working fluid becomes a low-temperature, low-pressure gas before flowing into the inlet of the compressor 310 to form a cycle.

[0072] When the photobioreactor 411 needs to be heated, the second working fluid pump 417 is activated, transferring heat from the heat storage tank 320 to the suspended radiation pipe network 414 to heat the photobioreactor 411. When the photobioreactor 411 needs to be cooled, the second working fluid pump 417 is activated, transferring cold energy from the cold storage tank 340 to the suspended radiation pipe network 414 to cool the photobioreactor 411.

[0073] If the temperature control system 300 is not started, the electrical energy generated by the turbine 230 will be stored in the second battery 260 for later use.

[0074] Simultaneously, the photovoltaic system 100 operates, and the photovoltaic panel assembly 110 can supply part of the generated electrical energy to the motor 412 in the light element module, so that the motor 412 can drive the spiral light element 413 to rotate and stir the culture medium in the photobioreactor 411; the remaining electrical energy generated by the photovoltaic panel assembly 110 can be stored in the first battery 130. At the same time, the third working fluid pump 423 in the hydrothermal system 420 can be started, thereby transporting the heat working fluid in the light-transmitting pipe 120 to the high-temperature heat storage medium in the hydrothermal tank 421 for heating and insulation.

[0075] (2) When the light intensity is insufficient to perform the light source intensity substandard mode;

[0076] The steam circulation system in ORC system 200 is not started. At this time, according to the temperature control requirements of open photobioreactor system 410, if temperature control is required, the compressor 310 in temperature control system 300 is powered by the second battery 260; otherwise, temperature control system 300 is not started.

[0077] Meanwhile, neither the photovoltaic panel group 110 nor the light-transmitting pipe 120 in the photovoltaic system 100 generates electricity; thus, the electric motor 412 in the open photobioreactor system 410 is powered by the first battery 130. Due to insufficient light, the spiral light element 413 can also emit light under the power supply of the first battery 130, thereby achieving supplemental lighting for microalgae cultivation.

[0078] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A solar-powered microalgae gas production energy conversion system, characterized in that, include: A microalgae gas production system, which is suitable for microalgae cultivation, hydrothermal pretreatment and anaerobic fermentation processes; A photovoltaic system, comprising photovoltaic panels and light-transmitting pipes, wherein the photovoltaic panels are made of a light-transmitting material; The light-transmitting pipe is laid flat below the photovoltaic panel group and connected to the microalgae gas generation system. The light-transmitting pipe is adapted to convert solar energy into heat energy and supply heat to the microalgae gas generation system. ORC system; the ORC system is adapted to power the temperature control system and supply the waste heat generated to the microalgae gas production system; and Temperature control system; the temperature control system is also adapted to supply heat to the microalgae gas generation system so that the microalgae gas generation system can utilize the waste heat of the ORC system and the temperature control system to control the temperature to be consistent with the process requirements. The microalgae gas generation system includes: An open photobioreactor system is provided, comprising a photobioreactor tank, a photoelectric module, a suspended radiation pipe network, and a second working fluid pump. The photobioreactor tank is used to hold microalgae, and the photoelectric module and the suspended radiation pipe network are both installed within the photobioreactor tank. The photoelectric module is adapted to be powered by a photovoltaic system. When the light intensity is sufficient, the photoelectric module only rotates and stirs; when the light intensity is insufficient, the photoelectric module emits light while rotating and stirring. The suspended radiation pipe network is adapted to be connected to a temperature control system via the second working fluid pump, so that the temperature of the photobioreactor tank can be controlled by the temperature control system to meet the process temperature requirements. A hydrothermal system is provided, comprising a hydrothermal tank, microalgae liquid pipelines, and a third working fluid pump. The hydrothermal tank is connected to the photovoltaic system via the third working fluid pump, allowing the photovoltaic system to maintain the high-temperature heat storage medium within the hydrothermal tank. Simultaneously, the working fluid carrying waste heat from the ORC system is suitable for passing through the hydrothermal tank, further maintaining the high-temperature heat storage medium within it. The microalgae liquid pipelines are installed within the hydrothermal tank, allowing the collected microalgae from the open photobioreactor system to flow into the microalgae liquid pipelines through the microalgae liquid inlet for hydrothermal reaction, thereby obtaining water-soluble organic matter. An anaerobic fermentation system includes an anaerobic fermenter containing a mesophilic heat storage medium. Water-soluble organic matter is introduced into the anaerobic fermenter through an inlet, absorbing heat from the mesophilic heat storage medium to maintain the anaerobic fermentation temperature. The resulting biogas is collected at the biogas outlet of the anaerobic fermenter. The working fluid of the ORC system, carrying residual heat, flows through the hydrothermal system and then through the anaerobic fermenter, thus maintaining the temperature of the mesophilic heat storage medium within the anaerobic fermenter. When the light intensity is sufficient, the photovoltaic system is suitable for heating the hydrothermal system and supplying power to the open photobioreactor system and the hydrothermal system, and storing the excess electricity; when the light intensity is insufficient, the photovoltaic system is suitable for supplying power to the open photobioreactor system and the hydrothermal system using the excess electricity.

2. The solar-powered microalgae gas production energy conversion system as described in claim 1, characterized in that: The photovoltaic system also includes a first storage battery; when the light intensity is sufficient, the photovoltaic panel array is adapted to receive sunlight and supply power to the microalgae gas generation system, and to store the excess electricity in the first storage battery; When the light intensity is insufficient, the first battery is adapted to supply power to the microalgae gas production system.

3. The solar-based microalgae gas production energy conversion system as described in claim 1, characterized in that: The ORC system includes a steam cycle system, a steam turbine, and a second battery. The steam circulation system is adapted to generate high-temperature steam to drive the steam turbine to generate electricity, and the electrical energy generated by the steam turbine is adapted to supply power to the temperature control system or be stored in the second battery; at the same time, the waste heat generated by the steam circulation system is adapted to supply heat to the microalgae gas generation system. When the light intensity is insufficient, the steam circulation system stops working, and at this time the second battery is adapted to supply power to the temperature control system.

4. The solar-powered microalgae gas production energy conversion system as described in claim 1, characterized in that: The temperature control system includes a compressor, a heat storage module, and a cold storage module connected in series. The compressor is adapted to compress the circulating working fluid into a high-temperature, high-pressure gas through the power supply of the ORC system. The high-temperature, high-pressure gas flows sequentially through the heat storage module and the cold storage module, so that the heat storage module and the cold storage module maintain heat storage and cold storage respectively. The heat storage module is adapted to regulate the temperature of the microalgae gas production system, and the cold storage module is adapted to regulate the temperature of the microalgae gas production system.

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