Off-grid photothermal natural gas heat source pressure difference power generation coupling system

Abstract

The application discloses an off-grid photo-thermal natural gas heat source pressure difference power generation coupling system and relates to the field of new energy power systems. The application generates high-temperature fluid by the heat of low-temperature molten salt generated by a photo-thermal power generation system and the heat of high-temperature flue gas of a natural gas emergency power generation system through a heat source well. The high-temperature fluid and constant-pressure cold water are distributed on both sides of a pressure difference membrane assembly. The steam on the high-temperature side is driven by the high-low temperature difference to flow from the high-temperature side to the low-temperature side through the pressure difference membrane. The steam is condensed on the low-temperature side to increase the pressure of the constant-pressure cold water, thereby driving a turbine generator to generate power. The power generated by the turbine generator is used for refrigeration. Even in the extreme case of solar energy resources, power can be generated by natural gas emergency power generation to supply power. The application realizes a stable, low-cost, efficient and combined power supply system for cooling, heating and power supply in an isolated network environment. The system assembly is simple, stable in performance, high in energy utilization efficiency and low in cost.

Description

Technical Field

[0001] This invention belongs to the field of new energy power systems, specifically relating to an off-grid solar thermal natural gas heat source differential pressure power generation coupling system. Background Technology

[0002] To utilize renewable energy sources such as solar thermal power to provide a stable combined cooling, heating, and power (CCHP) system for isolated grid environments, solar thermal power generation is currently the development trend of energy supply systems. However, in extreme situations involving solar energy resources, the following solutions can generally be adopted to ensure 24-hour cooling, heating, and power needs:

[0003] Option 1: Use only high-temperature steam for heating.

[0004] The heat exchange between the high-temperature molten salt and water in a concentrated solar power (CSP) system generates a large amount of high-temperature steam. CSP systems use this high-temperature steam to generate electricity. Therefore, to ensure CSP power generation, consuming steam for heating will increase the size of the high-temperature molten salt storage tank and the low-temperature molten salt storage tank, or reduce the amount of steam used for CSP power generation, thereby reducing CSP power generation and increasing the cost per kilowatt-hour.

[0005] Option 2, which uses only electric boilers for heating, directly consumes the electricity generated by solar radiation to drive the electric boilers for heating, resulting in excessively high heating costs.

[0006] To achieve a stable, efficient, and cost-effective combined cooling, heating, and power supply system, it is necessary to design a coupled tri-generation system that is suitable for off-grid operation, reduces carbon emissions and costs, has simple operating conditions, and efficiently utilizes energy. Summary of the Invention

[0007] In order to solve the above-mentioned problems in the existing technology, the present invention aims to provide an off-grid solar thermal natural gas heat source differential pressure power generation coupling system.

[0008] The technical solution adopted in this invention is as follows:

[0009] An off-grid solar thermal and natural gas heat source differential pressure power generation coupling system is characterized by comprising a solar thermal power generation system, a natural gas emergency power generation system, and a differential pressure power generation system; the solar thermal power generation system includes a solar thermal generator set and a cryogenic molten salt storage tank; the natural gas emergency power generation system includes a natural gas generator set and a high-temperature flue gas pipeline; the differential pressure power generation system includes a heat source well, a differential pressure membrane assembly, a cryogenic circulating pump, and a turbine generator; the electrical energy generated by the solar thermal generator set and the electrical energy generated by the natural gas generator set are directly used for power supply after being connected to the grid; the thermal energy of the cryogenic molten salt storage tank and the thermal energy of the high-temperature flue gas pipeline are incorporated into the heat source well, and the cryogenic circulating pump... The circulating pump is used to transport constant-pressure chilled water. The heat from the heat source well generates a high-temperature fluid through heat exchange. The high-temperature fluid output from the heat source well and the constant-pressure chilled water transported by the low-temperature circulating pump are respectively input to both sides of the differential pressure diaphragm assembly. The differential pressure diaphragm assembly outputs low-temperature fluid and pressurized chilled water. The low-temperature fluid is directly used for heating. The output end of the differential pressure diaphragm assembly is connected to a turbine generator. The pressurized chilled water is output to the turbine generator to drive the turbine generator to generate electricity. The turbine generator is used to power the refrigeration unit to achieve cooling. The pressurized chilled water output by the turbine generator is input to the heat source well through the water circulation pipe and absorbs heat energy to form a high-temperature fluid.

[0010] Optionally, the differential pressure membrane assembly includes a first differential pressure membrane element and a second differential pressure membrane element. The high-temperature fluid from the heat source well is connected to the input end of one side of the first differential pressure membrane element through a first steam pipe, and the constant-pressure chilled water delivered by the low-temperature circulating pump is connected to the input end of the other side of the first differential pressure membrane element through a constant-pressure chilled water pipe. The output end of one side of the first differential pressure membrane element is connected to the input end of one side of the second differential pressure membrane element through a second steam pipe, and the output end of the other side of the first differential pressure membrane element is connected to the input end of the other side of the second differential pressure membrane element through a first pressurized chilled water pipe. The output end of one side of the second differential pressure membrane element is connected to the heating system through a third steam pipe, and the output end of the other side of the second differential pressure membrane assembly is connected to the turbine generator through a second pressurized chilled water pipe.

[0011] Optionally, the solar thermal power generation system includes a concentrating field unit, molten salt pipes, a high-temperature molten salt storage tank, a low-temperature molten salt storage tank, and a solar thermal power generator set, which includes a steam generator. The concentrating field unit is used to absorb solar heat energy and exchange heat with the molten salt pipes, causing the heat-absorbing molten salt in the molten salt pipes to melt into a molten state. The melted molten salt is transported to the high-temperature molten salt storage tank. The molten salt in the high-temperature molten salt storage tank exchanges heat with water through a heat exchanger to heat the water into steam, which is then transported to the solar thermal power generator set for power generation. The high-temperature molten salt in the high-temperature molten salt storage tank becomes low-temperature molten salt after exchanging heat with water and is stored in the low-temperature molten salt storage tank. The low-temperature molten salt storage tank is connected to the heat source well through a low-temperature molten salt pipe.

[0012] Alternatively, the temperature of the molten salt in the cryogenic molten salt pipeline is 290°C.

[0013] Optionally, a power distribution room is provided between the turbine generator and the electric refrigeration unit. The power distribution room is used to store the electrical energy generated by the turbine generator and distribute the electrical energy to the end users. The end users of the electrical energy in the power distribution room include the electric refrigeration unit.

[0014] Optionally, both the first differential pressure membrane element and the second differential pressure membrane element include a differential pressure membrane.

[0015] Optionally, the media on both sides of the differential pressure membrane of the first differential pressure membrane element are a high-temperature fluid input from the first steam pipe and a constant-pressure cold water input from the constant-pressure cold water pipe, respectively.

[0016] Optionally, the media on both sides of the differential pressure membrane of the second differential pressure membrane element are high-temperature fluid input from the second steam pipe and pressurized cold water input from the first pressurized cold water pipe, respectively.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention provides an off-grid solar thermal and natural gas heat source differential pressure power generation coupling system. It utilizes a solar thermal power generation system combined with a natural gas emergency power generation system, fully leveraging solar energy while also utilizing natural gas for emergency power generation. This ensures stable power generation and supply even in isolated grid environments with extreme solar resource conditions. The invention uses a heat source well to generate a high-temperature fluid from the low-temperature molten salt produced by the solar thermal power generation system and the high-temperature flue gas from the natural gas emergency power generation system. This high-temperature fluid and constant-pressure chilled water are distributed on both sides of a differential pressure membrane assembly. The high-temperature steam in the high-temperature fluid flows from the high-temperature side to the low-temperature side, condensing on the low-temperature side and increasing the pressure of the constant-pressure chilled water. This drives a turbine generator to generate electricity, which is then used for cooling. Even in extreme solar resource conditions, electricity can be generated through the natural gas emergency power generation system, and the generated high-temperature flue gas provides stable and low-cost cooling and heating. This achieves a stable, low-cost, and efficient combined cooling, heating, and power generation system in isolated grid environments, replacing the high-cost solution of relying on steam extraction for continuous cooling and heating in isolated solar thermal power plants. The system components are simple, the performance is stable, the energy utilization efficiency is high, and the cost is low. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the connection relationship of the present invention.

[0020] In the diagram: 1-Central thermal power generation system, 2-Central thermal power generator set, 3-Low-temperature molten salt pipeline, 4-Natural gas emergency power generation system, 5-High-temperature flue gas pipeline, 6-Heat source well, 7-First steam pipeline, 8-First differential pressure membrane element, 9-Second steam pipeline, 10-Second differential pressure membrane element, 11-Third steam pipeline, 12-Low-temperature circulating pump, 13-Constant pressure chilled water pipeline, 14-First pressurized chilled water pipeline, 15-Second pressurized chilled water pipeline, 16-Turbine generator, 17-Power distribution room, 18-Electric refrigeration unit, 19-Water circulation pipeline. Detailed Implementation

[0021] In this embodiment, as Figure 1The diagram illustrates an off-grid solar thermal and natural gas heat source differential pressure power generation coupling system, comprising a solar thermal power generation system 1, a natural gas emergency power generation system 4, and a differential pressure power generation system. The solar thermal power generation system 1 includes a solar thermal generator set 2 and a cryogenic molten salt storage tank. The natural gas emergency power generation system 4 includes a natural gas generator set and a high-temperature flue gas pipeline 5. The differential pressure power generation system includes a heat source well 6, a differential pressure membrane assembly, a cryogenic circulating pump 12, and a turbine generator 16. The electrical energy generated by the solar thermal generator set 2 and the natural gas generator set is directly used for power supply after being connected to the grid. The thermal energy from the cryogenic molten salt storage tank and the high-temperature flue gas pipeline 5 is incorporated into the heat source well 6, and the cryogenic circulating pump 12 is used for power generation. In the process of supplying constant-pressure chilled water, the heat from the heat source well 6 generates a high-temperature fluid through heat exchange with the water. The high-temperature fluid output from the heat source well 6 and the constant-pressure chilled water supplied by the low-temperature circulating pump 12 are respectively input to both sides of the differential pressure diaphragm assembly. The differential pressure diaphragm assembly outputs low-temperature fluid and pressurized chilled water. The low-temperature fluid is directly used for heating. The output end of the differential pressure diaphragm assembly is connected to a turbine generator 16. The pressurized chilled water is output to the turbine generator 16, thereby driving the turbine generator 16 to generate electricity. The turbine generator 16 is used to power the cooling device 18 for cooling, thereby achieving cooling. The pressurized chilled water output from the turbine generator 16 is input to the heat source well 6 through the water circulation pipe 19 and absorbs heat energy to form a high-temperature fluid. By utilizing the solar thermal power generation system 1 in combination with the natural gas emergency power generation system 4, the solar energy is fully utilized while also using natural gas for emergency power generation, ensuring stable power generation and supply in the event of extreme solar energy resource conditions under isolated grid conditions. This invention utilizes a heat source well 6 to generate a high-temperature fluid from the heat of the low-temperature molten salt produced by the solar thermal power generation system 1 and the heat of the high-temperature flue gas from the natural gas emergency power generation system 4. This high-temperature fluid and constant-pressure chilled water are distributed on both sides of a differential pressure membrane assembly. The high and low temperature difference increases the pressure of the constant-pressure chilled water, thereby driving a turbine generator 16 to generate electricity. The electricity generated by the turbine generator 16 is then used for cooling. Even in extreme solar resource conditions, electricity generated by the natural gas emergency power generation system can be used for power supply, and the generated high-temperature flue gas provides stable and low-cost cooling and heating. This invention achieves a stable, low-cost, and efficient combined cooling, heating, and power supply system in an isolated grid environment, replacing the high-cost solution of relying on steam extraction for continuous cooling and heating in isolated grid solar thermal power plants. The system components of this invention are simple, the performance is stable, the energy utilization efficiency is high, and the cost is low.

[0022] It should be noted that the low-temperature fluid mentioned in this invention is lower in temperature than the high-temperature fluid generated by the heat source well 6, and is classified as low temperature; however, the temperature of the low-temperature fluid output from one side of the differential pressure membrane assembly is still higher than that of the constant-pressure cold water or pressurized cold water on the other side of the differential pressure membrane assembly, and is still classified as high temperature.

[0023] In this embodiment, the differential pressure membrane assembly includes two stages of differential pressure membrane elements, such as... Figure 1As shown, the differential pressure membrane assembly includes a first differential pressure membrane element 8 and a second differential pressure membrane element 10. The high-temperature fluid from the heat source well 6 is connected to the input end of one side of the first differential pressure membrane element 8 through a first steam pipe 7. The constant-pressure cold water delivered by the low-temperature circulating pump 12 is connected to the input end of the other side of the first differential pressure membrane element 8 through a constant-pressure cold water pipe 13. The output end of one side of the first differential pressure membrane element 8 is connected to the input end of one side of the second differential pressure membrane element 10 through a second steam pipe 9. The output end of the other side of the first differential pressure membrane element 8 is connected to the input end of the other side of the second differential pressure membrane element 10 through a first pressurized cold water pipe 14. The output end of one side of the second differential pressure membrane element 10 is connected to the heating system through a third steam pipe 11. The output end of the other side of the second differential pressure membrane assembly 10 is connected to the turbine generator 16 through a second pressurized cold water pipe 15.

[0024] In this embodiment, specifically, both the first differential pressure membrane element 8 and the second differential pressure membrane element 10 include a differential pressure membrane. The media on both sides of the differential pressure membrane of the first differential pressure membrane element 8 are the high-temperature fluid input from the first steam pipe 7 and the constant-pressure cold water input from the constant-pressure cold water pipe 13, respectively. The media on both sides of the differential pressure membrane of the second differential pressure membrane element 10 are the high-temperature fluid input from the second steam pipe 9 and the pressurized cold water input from the first pressurized cold water pipe 14, respectively. Since one side of the differential pressure membrane is the high-temperature fluid, which is the high-temperature side, and the other side is the constant-pressure cold water, which is the low-temperature side, a certain temperature difference will be generated on both sides of the differential pressure membrane. The temperature difference on both sides drives the high-temperature steam to flow from the high-temperature side to the low-temperature side. That is, the high-temperature steam can pass through the differential pressure membrane and enter the other side of the differential pressure membrane. After the high-temperature fluid condenses on the other side of the differential pressure membrane, it promotes the pressure increase on the other side of the differential pressure membrane, which increases the pressure of the constant-pressure cold water, forming a continuous flow of pressurized cold water. The pressurized cold water flow drives the turbine to generate electricity. It should be noted that the constant pressure chilled water or pressurized chilled water in this invention refers to water with a temperature lower than that of the high-temperature side of the differential pressure membrane assembly, rather than water with a temperature lower than a certain critical temperature.

[0025] The more high-temperature steam passes through the differential pressure membrane, the stronger the pressure on the constant-pressure chilled water on the low-temperature side becomes, while the pressure on the high-temperature side decreases, lowering the boiling point of water and thus reducing the steam temperature. Therefore, after passing through the first differential pressure membrane element 8, the second steam pipe 9 still contains a large amount of water vapor. Depending on the actual situation, two or more stages of differential pressure membrane elements can be set to regulate the flow rate of the pressurized chilled water, thereby controlling the power generation of the turbine used for cooling and the temperature of the high-temperature steam output to the heating system. The number of differential pressure membrane components can be selected according to the heating temperature requirements. For example, if the heating temperature in the above-mentioned invention is such that the temperature difference between the high-temperature steam output by the first differential pressure membrane element 8 and the second differential pressure membrane element 9 is 20°C, and if the required temperature needs to be further reduced by 20°C, a third differential pressure membrane element identical to the second differential pressure membrane element 9 can be added.

[0026] In this embodiment, specifically, the solar thermal power generation system 1 includes a concentrating field unit, a molten salt pipeline, a high-temperature molten salt storage tank, a low-temperature molten salt storage tank, and a solar thermal power generator set 2. The solar thermal power generator set 2 includes a steam generator. The concentrating field unit is used to absorb solar heat energy and exchange heat with the molten salt pipeline, causing the heat-absorbing molten salt in the molten salt pipeline to melt into a molten state. The melted molten salt is transported to the high-temperature molten salt storage tank. The molten salt in the high-temperature molten salt storage tank exchanges heat with water through a heat exchanger to heat the water into steam, which is then transported to the solar thermal power generator set 2 for power generation. The high-temperature molten salt in the high-temperature molten salt storage tank becomes low-temperature molten salt after exchanging heat with water and is stored in the low-temperature molten salt storage tank. The low-temperature molten salt storage tank is connected to the heat source well 6 through the low-temperature molten salt pipeline 3.

[0027] Concentrated solar power generation systems and natural gas power generation systems are widely used and mature technologies, and are knowledge that should be possessed by those skilled in the art and is easily accessible. Only the parts connected to this system are described here, and the rest are not described in detail.

[0028] In this embodiment, specifically, the molten salt temperature in the high-temperature molten salt storage tank is 540°C or higher, and the molten salt temperature in the low-temperature molten salt pipeline 3 is 290°C, making it possible to utilize the high thermal energy. It should be noted that the low temperature of the low-temperature molten salt storage tank and the low-temperature molten salt pipeline 3 refers to the temperature relative to the high-temperature molten salt storage tank. Compared to constant-pressure cold water or pressurized cold water, the temperature at which the low-temperature molten salt pipeline 3 is input into the heat source well 6 is still considered high.

[0029] In this embodiment, as Figure 1 As shown, a power distribution room 17 is also provided between the turbine generator 16 and the electric refrigeration device 18. The power distribution room 17 is used to store the electrical energy generated by the turbine generator 16 and to distribute the electrical energy to the user end after transformation. The user end of the power distribution room 17 includes the electric refrigeration device 18.

[0030] Specifically, the second pressurized chilled water pipe 15 is connected to the turbine generator 16, allowing the pressurized chilled water to drive the turbine generator 16 to generate electricity, which provides power to the electric refrigeration device 18 for cooling. At the same time, the pressurized chilled water that drives the turbine generator 16 to generate electricity flows back to the heat source well 6 through the water circulation pipe 19, continuing to maintain heat exchange circulation with the heat source well 6.

[0031] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to a connection within two components or an interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0033] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An off-grid, light-to-heat natural gas heat source pressure differential power coupling system, characterized by: It includes a solar thermal power generation system (1), a natural gas emergency power generation system (4), and a differential pressure power generation system; The solar thermal power generation system (1) includes a solar thermal generator set (2) and a low-temperature molten salt storage tank, and the natural gas emergency power generation system (4) includes a natural gas generator set and a high-temperature flue gas pipeline (5); The differential pressure power generation system includes a heat source well (6), a differential pressure membrane assembly, a cryogenic circulating pump (12), and a turbine generator (16); The electrical energy generated by the solar thermal generator set (2) and the electrical energy generated by the natural gas generator set are connected to the grid and used directly for power supply; The thermal energy of the low-temperature molten salt storage tank and the thermal energy of the high-temperature flue gas pipeline (5) are combined into the heat source well (6). The low-temperature circulating pump (12) is used to transport constant-pressure cold water. The heat of the heat source well (6) generates high-temperature fluid through heat exchange with water. The high-temperature fluid output from the heat source well (6) and the constant-pressure cold water transported by the low-temperature circulating pump (12) are respectively input to both sides of the differential pressure membrane assembly. The differential pressure membrane assembly outputs low-temperature fluid and pressurized cold water. The low-temperature fluid is directly used for heating. The output end of the differential pressure membrane assembly is connected to a turbine generator (16). The pressurized cold water is output to the turbine generator (16) to drive the turbine generator (16) to generate electricity. The turbine generator (16) is used to power the refrigeration device (18) to provide cooling. The pressurized cold water output by the turbine generator (16) is fed into the heat source well (6) through the water circulation pipe (19) and absorbs heat energy to form a high-temperature fluid.

2. The off-grid, photo-thermal natural gas heat source pressure difference power generation coupling system according to claim 1, characterized in that, The differential pressure membrane assembly includes a first differential pressure membrane element (8) and a second differential pressure membrane element (10). The high-temperature fluid of the heat source well (6) is connected to the input end of one side of the first differential pressure membrane element (8) through a first steam pipe (7). The constant-pressure cold water delivered by the low-temperature circulating pump (12) is connected to the input end of the other side of the first differential pressure membrane element (8) through a constant-pressure cold water pipe (13). The output end of the first differential pressure membrane element (8) is connected to the input end of the second differential pressure membrane element (10) through the second steam pipe (9). The output end of the first differential pressure membrane element (8) is connected to the input end of the second differential pressure membrane element (10) through the first pressurized cold water pipe (14). The output end of the second differential pressure membrane element (10) is connected to the heating system through the third steam pipe (11). The output end of the second differential pressure membrane assembly (10) is connected to the turbine generator (16) through the second pressurized cold water pipe (15).

3. The off-grid, photo-thermal natural gas heat source pressure difference power generation coupling system according to claim 1, characterized in that, The solar thermal power generation system (1) includes a concentrating field unit, molten salt pipeline, high-temperature molten salt storage tank, low-temperature molten salt storage tank and solar thermal power generation unit (2), wherein the solar thermal power generation unit (2) includes a steam generator; The concentrating field unit is used to absorb solar heat energy and exchange heat with the molten salt pipeline, so that the heat-absorbing molten salt in the molten salt pipeline melts into a molten state. The molten salt is then transported to a high-temperature molten salt storage tank. The molten salt in the high-temperature molten salt storage tank exchanges heat with water through a heat exchanger to heat the water into steam and then transports it to the solar thermal generator set (2) for power generation. After the high-temperature molten salt in the high-temperature molten salt storage tank exchanges heat with water, it becomes low-temperature molten salt and is stored in a low-temperature molten salt storage tank. The low-temperature molten salt storage tank is connected to the heat source well (6) through a low-temperature molten salt pipeline (3).

4. The off-grid, photothermal natural gas heat source pressure difference power generation coupling system according to claim 3, characterized in that, The temperature of the molten salt in the low-temperature molten salt pipeline (3) is 290°C.

5. The off-grid, photothermal natural gas heat source pressure difference power generation coupling system according to claim 1, characterized in that, A power distribution room (17) is also provided between the turbine generator (16) and the electric refrigeration device (18). The power distribution room (17) is used to store the electrical energy generated by the turbine generator (16) and distribute the electrical energy to the user end. The power supply terminal of the power distribution room (17) includes an electric cooling device (18).

6. The off-grid solar thermal natural gas heat source differential pressure power generation coupling system according to claim 2, characterized in that, Both the first differential pressure membrane element (8) and the second differential pressure membrane element (10) include a differential pressure membrane.

7. The off-grid solar thermal natural gas heat source differential pressure power generation coupling system according to claim 6, characterized in that, The media on both sides of the differential pressure membrane of the first differential pressure membrane element (8) are the high-temperature fluid input from the first steam pipe (7) and the constant-pressure cold water input from the constant-pressure cold water pipe (13).

8. The off-grid solar thermal natural gas heat source differential pressure power generation coupling system according to claim 6, characterized in that, The media on both sides of the differential pressure membrane of the second differential pressure membrane element (10) are the high-temperature fluid input from the second steam pipe (9) and the pressurized cold water input from the first pressurized cold water pipe (14), respectively.

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