Supercritical water solar thermal power generation system and power generation method
By using supercritical water as the heat transfer working fluid and designing a heat storage system in the solar thermal power generation system, the problem of low thermal conductivity and easy corrosion in traditional working fluids at high temperatures is solved, and an efficient, economical and safe solar thermal power generation effect is achieved.
Patent Information
- Application Number
- CN202510139709.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-08
- Publication Date
- 2025-05-13
AI Technical Summary
In the existing solar thermal power generation systems, traditional heat transfer working fluids such as water, carbon dioxide and molten salt have low thermal conductivity, are prone to corrosion and scale at high temperatures, resulting in low power generation efficiency, poor economicality and great safety hazards.
Supercritical water is used as the heat transfer working fluid, and heat is absorbed in the heat absorber through high-pressure water and reached the supercritical state, achieving a large temperature difference and a large enthalpy difference in heat extraction. At the same time, a heat storage system is designed to ensure the system operates normally in bad weather conditions.
It improves the power generation efficiency and economy of solar thermal power generation systems, extends the service life of heat absorbers, heat exchangers, and storage tanks, reduces system power consumption and operating costs, and enhances the safety and stability of the system.
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Figure CN119982126A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of solar thermal power generation, and relates to a supercritical water solar thermal power generation system and a power generation method. Background Art
[0002] In the development and utilization of renewable energy, solar thermal power generation technology has received widespread attention as a clean and renewable energy conversion method. This technology converts sunlight into thermal energy through solar collectors, and then uses the thermal energy to generate steam to drive turbines to generate electricity. In this process, the selection of heat transfer medium is crucial to the efficiency, stability and economy of the system.
[0003] As the most traditional absorber working fluid, water is widely used in solar thermal power generation systems due to its wide source and low cost. However, the thermal conductivity of water under normal conditions is relatively low, especially when it is close to the boiling point, its thermal conductivity will drop significantly, resulting in low thermal energy conversion efficiency. In addition, water is prone to corrosion and scaling at high temperatures, which will not only reduce the thermal efficiency of the system, but also damage the heat exchange equipment and shorten the system life. Carbon dioxide, as a gas, has a high thermal conductivity at high temperatures, but its heat capacity is small at normal pressure, resulting in limited heat absorption capacity. In addition, the chemical stability of carbon dioxide at high temperature and high pressure is also a challenge, which may affect the long-term operation of the system. Molten salt is used as an absorber working fluid because of its high thermal conductivity and specific heat capacity, especially in high-temperature thermal energy storage systems. However, the viscosity of molten salt is large and its fluidity is poor, which brings difficulties to the design and operation of the system. At the same time, molten salt is highly corrosive to equipment, requiring the use of special materials and anti-corrosion measures, which increases the cost of the system.
[0004] At present, the above three working fluids are the mainstream heat transfer working fluids in solar thermal power generation technology, with low power generation efficiency, poor economy and high safety risks. Summary of the invention
[0005] In order to overcome the problems existing in the prior art, the present invention provides a supercritical water solar thermal power generation system and power generation method, which uses supercritical water as a heat transfer medium to achieve large temperature difference and large enthalpy difference heat extraction, and realize efficient utilization of solar energy. At the same time, the heat storage system can ensure normal operation in bad weather, ensure the safe and stable operation of the solar thermal power generation system, increase the service life of the heat absorber, heat exchanger, and storage tank, and can reduce system power consumption and improve system efficiency.
[0006] To achieve the above object, the present invention adopts the following technical solutions:
[0007] (I) The present invention provides a supercritical water solar thermal power generation system, including a heat absorber, a heat exchanger, an energy storage and release device, a steam generator and a power generation mechanism; the heat absorber is arranged on the reflection light path of the mirror field, the heat absorber outlet is connected to the heat exchanger hot side inlet, and the heat exchanger hot side outlet is connected to the heat absorber inlet; high-pressure water absorbs heat through the heat absorber and reaches a supercritical state, the supercritical water enters the heat exchanger for heat exchange, and the high-pressure water cooled by heat exchange enters the heat absorber again, forming a solar supercritical water heat absorption cycle; the energy storage and release device energy storage outlet is connected to the heat exchanger cold side inlet, and the heat exchanger cold side outlet is connected to the energy storage and release device energy storage inlet; air absorbs heat through the heat exchanger and enters the energy storage and release device Exchange heat with the energy storage medium, and the air cooled by heat exchange enters the heat exchanger again to form an energy storage cycle; the energy release outlet of the energy storage and release device is connected to the hot side inlet of the steam generator, and the hot side outlet of the steam generator is connected to the energy release inlet of the energy storage and release device; the air absorbs heat through the energy storage and release device and enters the steam generator for heat exchange, and the air cooled by heat exchange enters the energy storage and release device again to form an energy release cycle; the power generation mechanism inlet is connected to the cold side outlet of the steam generator, and the cold side inlet of the steam generator is connected to the power generation mechanism outlet; high-pressure water absorbs heat through the steam generator and reaches a supercritical state, the supercritical water is supplied to the power generation mechanism to generate electricity, and the high-pressure water cooled by heat exchange enters the steam generator again to form a power generation cycle.
[0008] Furthermore, a cooling mechanism is provided on the passage between the hot side outlet of the heat exchanger and the inlet of the heat absorber; the cooling mechanism includes a water-to-water heat exchanger and a cooling tower; the hot side inlet of the water-to-water heat exchanger is connected to the hot side outlet of the heat exchanger, and the hot side outlet of the water-to-water heat exchanger is connected to the inlet of the heat absorber; the outlet of the cooling tower is connected to the cold side inlet of the water-to-water heat exchanger, and the cold side outlet of the water-to-water heat exchanger is connected to the inlet of the cooling tower.
[0009] Furthermore, the cooling mechanism also includes a centrifugal pump assembly; the centrifugal pump assembly is arranged between the cooling tower outlet and the cold side inlet of the water-to-water heat exchanger, and includes a first centrifugal pump and a second centrifugal pump connected in parallel; the inlets of the first centrifugal pump and the second centrifugal pump are both connected to the cooling tower outlet, and the outlets of the first centrifugal pump and the second centrifugal pump are both connected to the cold side inlet of the water-to-water heat exchanger; a valve is provided on the passage between the centrifugal pump assembly and the water-to-water heat exchanger.
[0010] Furthermore, a first water replenishment constant pressure device and a boosting device are provided on the passage between the hot side outlet of the water-to-water heat exchanger and the inlet of the heat absorber; the inlet of the boosting device is connected to the hot side outlet of the water-to-water heat exchanger, and the outlet of the boosting device is connected to the inlet of the heat absorber; the first water replenishment constant pressure device is connected in parallel to the passage between the boosting device and the water-to-water heat exchanger, and is connected to the boosting device.
[0011] Furthermore, the boosting device includes a first boosting pump and a second boosting pump in parallel; the inlets of the first boosting pump and the second boosting pump are both connected to the hot side outlet of the heat exchanger, the outlets of the first boosting pump and the second boosting pump are both connected to the inlet of the heat absorber, and the first water replenishment constant pressure device is connected to the first boosting pump and the second boosting pump.
[0012] Furthermore, a first cyclone separator and a first high-temperature variable frequency fan are arranged on the passage between the energy storage outlet of the energy storage and release device and the cold side inlet of the heat exchanger; the inlet of the first cyclone separator is connected to the energy storage outlet of the energy storage and release device, the outlet of the first cyclone separator is connected to the inlet of the first high-temperature variable frequency fan, and the outlet of the first high-temperature variable frequency fan is connected to the cold side inlet of the heat exchanger.
[0013] Furthermore, a second cyclone separator is arranged on the passage between the energy release outlet of the energy storage and release device and the hot side inlet of the steam generator, the inlet of the second cyclone separator is connected to the energy release outlet of the energy storage and release device, and the outlet of the second cyclone separator is connected to the hot side inlet of the steam generator; a second high-temperature variable frequency fan is arranged on the passage between the energy release inlet of the energy storage and release device and the hot side outlet of the steam generator, the inlet of the second high-temperature variable frequency fan is connected to the hot side outlet of the steam generator, and the outlet of the second high-temperature variable frequency fan is connected to the energy release inlet of the energy storage and release device.
[0014] Furthermore, the power generation mechanism includes a steam turbine, a generator, a condenser, a second water-makeup constant pressure device and a centrifugal pump; the steam turbine inlet is connected to the cold side outlet of the steam generator, the steam turbine outlet is connected to the condenser inlet, and the steam turbine supplies electricity to the generator; the condenser outlet is connected to the centrifugal pump inlet, and the centrifugal pump outlet is connected to the cold side inlet of the steam generator; the second water-makeup constant pressure device is connected in parallel to the passage between the condenser and the centrifugal pump, and is connected to the centrifugal pump.
[0015] Furthermore, the energy storage and release device is a double-layer storage tank, including a first storage tank and a second storage tank, the second storage tank is nested in the first storage tank, and the first storage tank and the second storage tank are both filled with energy storage medium; the first storage tank and the second storage tank are arranged in parallel in the energy storage circulation passage and the energy release circulation passage, and the first storage tank and the second storage tank alternately store and release energy; the energy storage medium is solid heat storage particles, specifically quartz, pebbles or ceramics; a first inlet pipeline and a first outlet pipeline are arranged on the top of the first storage tank, and a second inlet pipeline and a second outlet pipeline are arranged on the top of the second storage tank; the first inlet pipeline and the second inlet pipeline are energy storage particles. inlet, connected in parallel with each other and connected to the cold side outlet of the heat exchanger; the first outlet pipeline and the second outlet pipeline are energy release outlets, connected in parallel with each other and connected to the inlet of the second cyclone separator; a third inlet pipeline and a third outlet pipeline are arranged at the bottom of the first storage tank, and a fourth inlet pipeline and a fourth outlet pipeline are arranged at the bottom of the second storage tank; the third inlet pipeline and the fourth inlet pipeline are energy release inlets, connected in parallel with each other and connected to the outlet of the second high-temperature variable frequency fan; the third outlet pipeline and the fourth outlet pipeline are energy storage outlets, connected in parallel with each other and connected to the inlet of the first cyclone separator; valves are arranged on each inlet pipeline and outlet pipeline.
[0016] Furthermore, the heat absorber is a cyclone heat absorber; the heat exchanger is a fin tube heat exchanger; and the water-to-water heat exchanger is a wound tube heat exchanger.
[0017] Furthermore, a first pressure indicator and a first flow indicator are provided at the inlet of the heat absorber; a first temperature indicator, a second flow indicator and a second pressure indicator are provided at the outlet of the heat absorber; a second temperature indicator and a third pressure indicator are provided at the hot side outlet of the heat exchanger; a third temperature indicator and a fourth pressure indicator are provided at the hot side outlet of the water-to-water heat exchanger; a fourth temperature indicator is provided at the cold side outlet of the heat exchanger; a fifth temperature indicator is provided at the energy storage outlet of the energy storage and release device; a sixth temperature indicator is provided at the energy release outlet of the energy storage and release device; and a seventh temperature indicator is provided at the hot side outlet of the steam generator.
[0018] (II) The present invention also provides a supercritical water solar thermal power generation method, which is implemented by the power generation system described above, comprising:
[0019] Heat absorption cycle: The heat absorber absorbs energy through reflection in the mirror field, and the booster device is started to boost the water pressure. The high-pressure water enters the heat absorber to absorb heat and reaches a supercritical state, and then enters the heat exchanger for heat exchange. When the temperature of the high-pressure water after heat exchange cooling is higher than the preset value, it enters the cooling mechanism for cooling. The cooled high-pressure water enters the heat absorber again for the next round of heat absorption cycle.
[0020] Energy storage cycle: air enters the heat exchanger to exchange heat with supercritical water, then enters the energy storage and release device to exchange heat with the energy storage medium. The energy storage medium absorbs heat and stores energy. The air cooled by heat exchange enters the heat exchanger again for the next round of energy storage cycle.
[0021] Energy release cycle: Another air enters the energy storage and release device to absorb heat from the energy storage medium, and then enters the steam generator to release heat. The heat exchanged and cooled air enters the energy storage and release device again for the next round of energy release cycle;
[0022] Power generation cycle: Another high-pressure water absorbs heat through the steam generator and reaches a supercritical state. The supercritical water is supplied to the power generation mechanism to generate electricity, and then condensed. The condensed high-pressure water enters the steam generator again for the next round of power generation.
[0023] The beneficial effects of the present invention are:
[0024] (1) In the solar supercritical water heat absorption system of the present invention, the absorber uses high-pressure water supercritical heat extraction to replace traditional water, carbon dioxide, molten salt and other working fluids, which has the following advantages: ① High thermal conductivity and heat capacity: In the supercritical state, the thermal conductivity and heat capacity of water are significantly improved, which is particularly suitable for high-temperature heat exchange processes; ② Excellent flow properties: Supercritical water has low viscosity and good fluidity, which is conducive to heat exchange and circulation; ③ High temperature stability: Supercritical water has good chemical stability under high temperature and high pressure, and is not easy to corrode equipment, ensuring the long-term operation of the system; ④ Environmentally friendly: Water, as an environmentally friendly heat transfer working fluid, will not have a negative impact on the environment. It achieves large enthalpy difference and large temperature difference heat extraction, which can greatly improve the power generation efficiency of the solar thermal power generation system;
[0025] (2) Compared with traditional solar thermal power generation systems, the present invention can achieve higher operating temperatures, reaching 700°C and above. This feature not only improves the thermal efficiency of the system, but also effectively improves the conversion efficiency of electrical energy. Traditional solar thermal power generation systems usually operate in the range of 400°C to 500°C, which to a certain extent limits their overall performance. The advanced materials and designs used in the present invention enable it to withstand higher temperatures, thereby improving the utilization rate of thermal energy;
[0026] (3) In the double-layer heat storage and release system of the present invention, a sleeve-type double tank structure is adopted, one for charging and one for discharging, which can avoid the instability of solar energy resources and ensure that the system can operate normally in bad weather;
[0027] (4) The working fluid in the system of the present invention adopts a closed cycle, without exhaust gas emission, which is more environmentally friendly than traditional power generation processes. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 This is a schematic diagram of the supercritical water solar thermal power generation system of the present invention;
[0029] The symbols in the accompanying drawings are:
[0030] 1. Mirror field; 2. Heat absorber; 3. Heat exchanger; 4. Water-to-water heat exchanger; 5. First water supply and constant pressure device; 6-1. First booster pump; 6-2. Second booster pump; 7. Cooling tower; 8-1. First centrifugal pump; 8-2. Second centrifugal pump; 9. First high-temperature variable-frequency fan; 10. Energy storage and release device; 11. First cyclone separator; 12. Second high-temperature variable-frequency fan; 13. Second cyclone separator; 14. Steam generator; 15. Steam turbine; 16. Generator; 17. Condenser; 18. Second water supply and constant pressure device; 19. Centrifugal pump. DETAILED DESCRIPTION
[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0032] like Figure 1 As shown, the present invention provides a supercritical water solar thermal power generation system, including a heat absorber 2 (cyclone heat absorber), a heat exchanger 3 (fin tube heat exchanger), an energy storage and release device 10, a steam generator 14 and a power generation mechanism.
[0033] The absorber 2 is arranged on the reflected light path of the mirror field 1, and the outlet of the absorber 2 is connected to the hot side inlet of the heat exchanger 3, and the hot side outlet of the heat exchanger 3 is connected to the inlet of the absorber 2. When in use, the high-pressure water absorbs heat through the absorber 2 and reaches a supercritical state, the supercritical water enters the heat exchanger 3 for heat exchange, and the high-pressure water cooled by heat exchange enters the absorber 2 again, forming a solar supercritical water heat absorption cycle.
[0034] The energy storage outlet of the energy storage and release device 10 is connected to the cold side inlet of the heat exchanger 3, and the cold side outlet of the heat exchanger 3 is connected to the energy storage inlet of the energy storage and release device 10. When used, the air absorbs heat through the heat exchanger 3, enters the energy storage and release device 10 to exchange heat with the energy storage medium, releases heat to the energy storage medium, and the air cooled by heat exchange enters the heat exchanger 3 again, forming an energy storage cycle.
[0035] The energy release outlet of the energy storage and release device 10 is connected to the hot side inlet of the steam generator 14, and the hot side outlet of the steam generator 14 is connected to the energy release inlet of the energy storage and release device 10. When in use, the energy storage medium in the energy storage and release device 10 transfers heat to the air, and the air absorbs heat and heats up through the energy storage and release device 10, then enters the steam generator 14 for heat exchange and cooling, and the heat exchanged and cooled air enters the energy storage and release device 10 again, forming an energy release cycle.
[0036] The inlet of the power generation mechanism is connected to the cold side outlet of the steam generator 14, and the cold side inlet of the steam generator 14 is connected to the outlet of the power generation mechanism. When in use, the high-pressure water absorbs heat through the steam generator 14 and reaches a supercritical state. The supercritical water supplies the power generation mechanism to generate electricity, and the high-pressure water cooled by heat exchange enters the steam generator 14 again, forming a power generation cycle.
[0037] Among them, a first pressure indicator PI1 and a first flow indicator FI1 are provided at the inlet of the heat absorber 2, a first temperature indicator TI1, a second flow indicator FI2 and a second pressure indicator PI2 are provided at the outlet of the heat absorber 2, a second temperature indicator TI2 and a third pressure indicator PI3 are provided at the hot side outlet of the heat exchanger 3, a fourth temperature indicator TI4 is provided at the cold side outlet of the heat exchanger 3, a seventh temperature indicator TI7 is provided at the hot side outlet of the steam generator 14, a fifth temperature indicator TI5 is provided at the energy storage outlet of the energy storage and release device 10, and a sixth temperature indicator TI6 is provided at the energy release outlet of the energy storage and release device 10.
[0038] like Figure 1 As shown, in a preferred embodiment, a cooling mechanism is provided on the passage between the hot side outlet of the heat exchanger 3 and the inlet of the heat absorber 2. The cooling mechanism includes a water-to-water heat exchanger 4 (a wound tube heat exchanger), a cooling tower 7 and a centrifugal pump assembly. The hot side inlet of the water-to-water heat exchanger 4 is connected to the hot side outlet of the heat exchanger 3, and the hot side outlet of the water-to-water heat exchanger 4 is connected to the inlet of the heat absorber 2; the outlet of the cooling tower 7 is connected to the inlet of the centrifugal pump assembly, and the outlet of the centrifugal pump assembly is connected to the cold side inlet of the water-to-water heat exchanger 4, and the cold side outlet of the water-to-water heat exchanger 4 is connected to the inlet of the cooling tower 7. A valve is provided on the passage between the centrifugal pump assembly and the water-to-water heat exchanger 4, and a third temperature indicator TI3 and a fourth pressure indicator PI4 are provided at the hot side outlet of the water-to-water heat exchanger 4.
[0039] like Figure 1 As shown, in a preferred embodiment, the centrifugal pump assembly includes a first centrifugal pump 8-1 and a second centrifugal pump 8-2 connected in parallel, the inlets of the first centrifugal pump 8-1 and the second centrifugal pump 8-2 are both connected to the outlet of the cooling tower 7, and the outlets of the first centrifugal pump 8-1 and the second centrifugal pump 8-2 are both connected to the cold side inlet of the water-to-water heat exchanger 4. This design adopts a parallel double pipeline with one in use and one in reserve, and when one centrifugal pump fails, another centrifugal pump can be replaced to continuously provide power for the cooling water and ensure the stable operation of the system.
[0040] like Figure 1 As shown, in a preferred embodiment, a first water replenishment constant pressure device 5 and a boosting device are provided on the passage between the hot side outlet of the water-to-water heat exchanger 4 and the inlet of the heat absorber 2, the inlet of the boosting device is connected to the hot side outlet of the water-to-water heat exchanger 4, and the outlet of the boosting device is connected to the inlet of the heat absorber 2.
[0041] like Figure 1 As shown, in a preferred embodiment, the boosting device includes a first boosting pump 6-1 and a second boosting pump 6-2 in parallel, the inlets of the first boosting pump 6-1 and the second boosting pump 6-2 are both connected to the hot side outlet of the heat exchanger 3, the outlets of the first boosting pump 6-1 and the second boosting pump 6-2 are both connected to the inlet of the heat absorber 2, and the first water replenishment constant pressure device 5 is connected to the first boosting pump 6-1 and the second boosting pump 6-2. This design adopts a parallel double pipeline with one for use and one for backup, and can replace another boosting pump when one boosting pump fails, and can continuously boost the pressure of normal pressure water and provide flow power for high-pressure gas to ensure the stable operation of the system. The first water replenishment constant pressure device 5 is connected in parallel to the passage between the boosting device and the water-to-water heat exchanger 4, and is connected to the boosting device. When the fourth pressure indicator PI4 indicates that the pressure does not meet the preset (23MPa), the water in the first water replenishment constant pressure device 5 can be extracted and pressurized by the first boosting pump 6-1 or the second boosting pump 6-2.
[0042] like Figure 1 As shown, in a preferred embodiment, a first cyclone separator 11 and a first high-temperature variable frequency fan 9 are arranged on the passage between the energy storage outlet of the energy storage and release device 10 and the cold side inlet of the heat exchanger 3. The inlet of the first cyclone separator 11 is connected to the energy storage outlet of the energy storage and release device 10, the outlet of the first cyclone separator 11 is connected to the inlet of the first high-temperature variable frequency fan 9, and the outlet of the first high-temperature variable frequency fan 9 is connected to the cold side inlet of the heat exchanger 3. The first cyclone separator 11 is used for dust removal, and the first high-temperature variable frequency fan 9 is used to provide power for the circulation of high-pressure water.
[0043] like Figure 1 As shown, in a preferred embodiment, a second cyclone separator 13 for dust removal is provided on the passage between the energy release outlet of the energy storage and release device 10 and the hot side inlet of the steam generator 14, the inlet of the second cyclone separator 13 is connected to the energy release outlet of the energy storage and release device 10, and the outlet of the second cyclone separator 13 is connected to the hot side inlet of the steam generator 14. A second high-temperature variable frequency fan 12 for providing power for the circulation flow of gas is provided on the passage between the energy release inlet of the energy storage and release device 10 and the hot side outlet of the steam generator 14, the inlet of the second high-temperature variable frequency fan 12 is connected to the hot side outlet of the steam generator 14, and the outlet of the second high-temperature variable frequency fan 12 is connected to the energy release inlet of the energy storage and release device 10.
[0044] like Figure 1As shown, the power generation mechanism includes a steam turbine 15, a generator 16, a condenser 17, a second water supply constant pressure device 18 and a centrifugal pump 19. The inlet of the steam turbine 15 is connected to the cold side outlet of the steam generator 14, and the outlet of the steam turbine 15 is connected to the inlet of the condenser 17. The steam turbine 15 supplies electricity to the generator 16. The outlet of the condenser 17 is connected to the inlet of the centrifugal pump 19, and the outlet of the centrifugal pump 19 is connected to the cold side inlet of the steam generator 14. The second water supply constant pressure device 18 is connected in parallel to the passage between the condenser 17 and the centrifugal pump 19, and is connected to the centrifugal pump 19.
[0045] like Figure 1 As shown, in a preferred embodiment, the energy storage and release device 10 is a double-layer storage tank, including a first storage tank and a second storage tank, the second storage tank is nested in the first storage tank, and the first storage tank and the second storage tank are both filled with quartz medium; the first storage tank and the second storage tank are arranged in parallel in the energy storage circulation passage and the energy release circulation passage, and the first storage tank and the second storage tank alternately store and release energy. The first inlet pipeline and the first outlet pipeline are arranged on the top of the first storage tank, and the second inlet pipeline and the second outlet pipeline are arranged on the top of the second storage tank; the first inlet pipeline and the second inlet pipeline are energy storage inlets, connected in parallel with each other and connected to the cold side outlet of the heat exchanger 3; the first outlet pipeline and the second outlet pipeline are energy release outlets, connected in parallel with each other and connected to the inlet of the second cyclone separator 13; the third inlet pipeline and the third outlet pipeline are arranged on the bottom of the first storage tank, and the fourth inlet pipeline and the fourth outlet pipeline are arranged on the bottom of the second storage tank; the third inlet pipeline and the fourth inlet pipeline are energy release inlets, connected in parallel with each other and connected to the outlet of the second high-temperature variable frequency fan 12; the third outlet pipeline and the fourth outlet pipeline are energy storage outlets, connected in parallel with each other and connected to the inlet of the first cyclone separator 11; valves are arranged on each inlet pipeline and outlet pipeline. This design adopts a sleeve-type double-tank structure with one charge and one discharge, so that the first storage tank and the second storage tank store and release energy alternately, which can ensure the continuous and stable operation of the power generation system.
[0046] In the present invention, the absorber 2 adopts a cyclone absorber, which is composed of two main parts: an inner tube and an exposed pipe. The sunlight is reflected by the heliostat field and directly irradiated on the pipe. The cyclone pipe is adopted, and the pipe can expand freely at high temperature, which greatly reduces the damage of thermal stress. The working medium is high-pressure water, which takes heat and transfers the high-temperature heat energy of the sun in supercritical, large temperature difference, and large enthalpy difference. The heat exchanger 3 adopts a finned tube heat exchanger, and the high-pressure water transfers heat to the heat-carrying fluid in the heat exchanger 3. The water-to-water heat exchanger 4 adopts a wound tube heat exchanger, and the high-pressure water flows in the pipe, and the cooling water flows in the pipe to cool the high-pressure water.
[0047] The power generation method of the above-mentioned supercritical water solar thermal power generation system is as follows:
[0048] Heat absorption cycle: During the day, the solar energy resource conditions are good, the absorber 2 absorbs energy through reflection by the mirror field 1, the first booster pump 6-1 is started (when the first booster pump 6-1 fails, the second booster pump 6-2 is enabled), the water stored in the first water replenishment constant pressure device 5 is pumped out and pressurized, the first flow indicator FI1 and the first pressure indicator PI1 (23MPa and above) are observed, and after the state of the water at the inlet of the absorber 2 is determined, the pressurized high-pressure water enters the absorber 2 to absorb heat and reaches a supercritical state (710°C, 23MPa), the second pressure indicator PI2, the first temperature indicator TI1 and the second flow indicator FI2 are observed, and it is confirmed The state of the water at the outlet of the fixed heat absorber 2 is then transported to the heat exchanger 3 for heat exchange with the air. The high-pressure water after heat exchange flows out of the heat exchanger 3. Observe the second temperature indicator TI2 and the third pressure indicator PI3, and flow into the hot side of the water-to-water heat exchanger. When the second temperature indicator TI2 shows that the temperature is higher than the preset value (90°C), the valve controlled by the temperature between the centrifugal pump assembly and the water-to-water heat exchanger 4 is opened, and the first centrifugal pump 8-1 is started (when the first centrifugal pump 8-1 fails, the second centrifugal pump 8-2 is enabled), and the cooling water in the cooling tower 7 is sent to the cold side inlet of the water-to-water heat exchanger 4 for heat exchange with the high-pressure water working medium, and circulates again after the temperature drops to the preset temperature. Observe the third temperature indicator TI3 and the fourth pressure indicator PI4. When the pressure indicator value does not meet the preset value (23MPa), start the first water replenishment constant pressure device 5.
[0049] Energy storage cycle: The first high-temperature variable frequency fan 9 delivers air to the heat exchanger 3, where the air exchanges heat with supercritical water and is heated to 680°C (observe the fourth temperature indicator TI4), and then enters the first storage tank of the energy storage and release device 10 ( Figure 1 The solid particles in the first storage tank exchange heat with the solid particles in the first storage tank, and the solid particles absorb and store the high-temperature heat energy carried by the air, reaching 650°C. The air after heat exchange flows out of the energy storage and release device 10 and drops to a certain temperature, then passes through the first cyclone separator 11 for dust removal, and is finally sent back to the heat exchanger 3 by the first high-temperature variable frequency fan 9 for the next round of energy storage cycle.
[0050] Energy release cycle: The second high temperature variable frequency fan 12 delivers air to the second storage tank of the energy storage and release device 10 ( Figure 1 In tank B, the solid particles in the second storage tank store high-temperature heat, and the air exchanges heat with the solid particles to reach 620°C. After dust removal by the second cyclone separator 13, it enters the steam generator 14 to exchange heat with water. The heat-exchanged and cooled air is again sent by the second high-temperature variable-frequency fan 12 to the energy storage and release device 10 for the next round of energy release cycle.
[0051] Power generation cycle: The centrifugal pump 19 delivers 25MPa water to the steam generator 14. After being heated by the steam generator 14, the water reaches a supercritical state (580°C, 25MPa), drives the steam turbine 15 and the generator 16 to generate electricity, and then is condensed by the condenser 17. The condensed high-pressure water enters the steam generator 14 again through the centrifugal pump 19 for the next power generation cycle.
[0052] At night, the heat absorption process of the solar thermal power generation system stops, the first storage tank of the energy storage and release device 10 stops storing heat, and the second storage tank can continue to release energy and continue to generate electricity. During the day, after the heat is released, the second storage tank of the energy storage and release device 10 stops releasing heat and starts storing heat, and the first storage tank continues to release energy and continue to generate electricity. At night, the first storage tank of the energy storage and release device 10 continues to release heat, and the second storage tank stops storing heat. This cycle generates electricity.
[0053] The present invention improves the economic efficiency of the solar thermal power generation system and realizes the effective use of solar thermal energy throughout the day. Through reasonable system design, large temperature difference and large enthalpy difference heat extraction are achieved, and efficient use of solar energy is achieved. At the same time, the heat storage system can ensure normal operation in bad weather, reduce the impact of thermal stress caused by temperature difference, ensure the safe and stable operation of the solar thermal power generation system, increase the service life of the heat absorber, heat exchanger, and storage tank, and can reduce system power consumption, reduce system operating costs, and improve system efficiency.
[0054] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.
Claims
1. A supercritical water solar thermal power generation system, characterized in that: It comprises a heat absorber (2), a heat exchanger (3), an energy storage and release device (10), a steam generator (14) and a power generation mechanism; The heat absorber (2) is arranged on the reflection light path of the mirror field (1); the outlet of the heat absorber (2) is connected to the hot side inlet of the heat exchanger (3); the hot side outlet of the heat exchanger (3) is connected to the inlet of the heat absorber (2); the high-pressure water absorbs heat through the heat absorber (2) and reaches a supercritical state; the supercritical water enters the heat exchanger (3) for heat exchange; the high-pressure water cooled by heat exchange enters the heat absorber (2) again, thus forming a solar supercritical water heat absorption cycle; The energy storage outlet of the energy storage and release device (10) is connected to the cold side inlet of the heat exchanger (3), and the cold side outlet of the heat exchanger (3) is connected to the energy storage inlet of the energy storage and release device (10); air absorbs heat through the heat exchanger (3), enters the energy storage and release device (10) to exchange heat with the energy storage medium, and the air cooled by heat exchange enters the heat exchanger (3) again, thus forming an energy storage cycle; The energy release outlet of the energy storage and release device (10) is connected to the hot side inlet of the steam generator (14), and the hot side outlet of the steam generator (14) is connected to the energy release inlet of the energy storage and release device (10); air absorbs heat through the energy storage and release device (10), enters the steam generator (14) for heat exchange, and the air cooled by heat exchange enters the energy storage and release device (10) again, thus forming an energy release cycle; The inlet of the power generation mechanism is connected to the cold side outlet of the steam generator (14), and the cold side inlet of the steam generator (14) is connected to the outlet of the power generation mechanism; the high-pressure water absorbs heat through the steam generator (14) and reaches a supercritical state, the supercritical water is supplied to the power generation mechanism to generate electricity, and the high-pressure water cooled by heat exchange enters the steam generator (14) again, forming a power generation circulation path.
2. The supercritical water solar thermal power generation system according to claim 1, characterized in that: A cooling mechanism is provided on the passage between the hot side outlet of the heat exchanger (3) and the inlet of the heat absorber (2); The cooling mechanism comprises a water-to-water heat exchanger (4) and a cooling tower (7); The hot side inlet of the water-to-water heat exchanger (4) is connected to the hot side outlet of the heat exchanger (3), and the hot side outlet of the water-to-water heat exchanger (4) is connected to the inlet of the heat absorber (2); the outlet of the cooling tower (7) is connected to the cold side inlet of the water-to-water heat exchanger (4), and the cold side outlet of the water-to-water heat exchanger (4) is connected to the inlet of the cooling tower (7).
3. The supercritical water solar thermal power generation system according to claim 2, characterized in that: The cooling mechanism also includes a centrifugal pump assembly; The centrifugal pump assembly is arranged between the outlet of the cooling tower (7) and the cold side inlet of the water-to-water heat exchanger (4), and comprises a first centrifugal pump (8-1) and a second centrifugal pump (8-2) connected in parallel; The inlets of the first centrifugal pump (8-1) and the second centrifugal pump (8-2) are both connected to the outlet of the cooling tower (7), and the outlets of the first centrifugal pump (8-1) and the second centrifugal pump (8-2) are both connected to the cold side inlet of the water-to-water heat exchanger (4); A valve is provided on the passage between the centrifugal pump assembly and the water-to-water heat exchanger (4).
4. The supercritical water solar thermal power generation system according to claim 2, characterized in that: A first water replenishment constant pressure device (5) and a pressure boosting device are provided on the passage between the hot side outlet of the water-to-water heat exchanger (4) and the inlet of the heat absorber (2); The inlet of the boosting device is connected to the hot side outlet of the water-to-water heat exchanger (4), and the outlet of the boosting device is connected to the inlet of the heat absorber (2); the first water replenishment constant pressure device (5) is connected in parallel to the passage between the boosting device and the water-to-water heat exchanger (4), and is connected to the boosting device.
5. The supercritical water solar thermal power generation system according to claim 4, characterized in that: The boosting device comprises a first boosting pump (6-1) and a second boosting pump (6-2) connected in parallel; The inlets of the first booster pump (6-1) and the second booster pump (6-2) are both connected to the hot side outlet of the heat exchanger (3), the outlets of the first booster pump (6-1) and the second booster pump (6-2) are both connected to the inlet of the heat absorber (2), and the first water replenishment constant pressure device (5) is connected to the first booster pump (6-1) and the second booster pump (6-2).
6. The supercritical water solar thermal power generation system according to claim 1, characterized in that: A first cyclone separator (11) and a first high-temperature variable frequency fan (9) are provided on the passage between the energy storage outlet of the energy storage and release device (10) and the cold side inlet of the heat exchanger (3); The inlet of the first cyclone separator (11) is connected to the energy storage outlet of the energy storage and release device (10), the outlet of the first cyclone separator (11) is connected to the inlet of the first high-temperature variable-frequency fan (9), and the outlet of the first high-temperature variable-frequency fan (9) is connected to the cold side inlet of the heat exchanger (3).
7. The supercritical water solar thermal power generation system according to claim 1, characterized in that: A second cyclone separator (13) is provided on the passage between the energy release outlet of the energy storage and release device (10) and the hot side inlet of the steam generator (14); the inlet of the second cyclone separator (13) is connected to the energy release outlet of the energy storage and release device (10), and the outlet of the second cyclone separator (13) is connected to the hot side inlet of the steam generator (14); A second high-temperature variable-frequency fan (12) is arranged on the passage between the energy release inlet of the energy storage and release device (10) and the hot side outlet of the steam generator (14); the inlet of the second high-temperature variable-frequency fan (12) is connected to the hot side outlet of the steam generator (14); and the outlet of the second high-temperature variable-frequency fan (12) is connected to the energy release inlet of the energy storage and release device (10).
8. The supercritical water solar thermal power generation system according to claim 1, characterized in that: The power generation mechanism comprises a steam turbine (15), a generator (16), a condenser (17), a second water replenishment constant pressure device (18) and a centrifugal pump (19); The inlet of the steam turbine (15) is connected to the outlet of the cold side of the steam generator (14), and the outlet of the steam turbine (15) is connected to the inlet of the condenser (17). The steam turbine (15) supplies electricity to the generator (16). The outlet of the condenser (17) is connected to the inlet of the centrifugal pump (19), and the outlet of the centrifugal pump (19) is connected to the inlet of the cold side of the steam generator (14). The second water replenishment constant pressure device (18) is connected in parallel to the passage between the condenser (17) and the centrifugal pump (19), and is connected to the centrifugal pump (19).
9. The supercritical water solar thermal power generation system according to claim 1, characterized in that: The energy storage and release device (10) is a double-layer storage tank, comprising a first storage tank and a second storage tank, wherein the second storage tank is nested in the first storage tank, and the first storage tank and the second storage tank are both filled with energy storage medium; the first storage tank and the second storage tank are arranged in parallel in the energy storage circulation path and the energy release circulation path, and the first storage tank and the second storage tank store and release energy alternately; the energy storage medium is solid heat storage particles, specifically quartz, pebbles or ceramics; A first inlet pipeline and a first outlet pipeline are arranged on the top of the first storage tank, and a second inlet pipeline and a second outlet pipeline are arranged on the top of the second storage tank; the first inlet pipeline and the second inlet pipeline are energy storage inlets, connected in parallel to each other and connected to the cold side outlet of the heat exchanger (3); the first outlet pipeline and the second outlet pipeline are energy release outlets, connected in parallel to each other and connected to the inlet of the second cyclone separator (13); A third inlet pipeline and a third outlet pipeline are arranged at the bottom of the first storage tank, and a fourth inlet pipeline and a fourth outlet pipeline are arranged at the bottom of the second storage tank; the third inlet pipeline and the fourth inlet pipeline are energy release inlets, connected in parallel with each other and connected to the outlet of the second high-temperature variable frequency fan (12); the third outlet pipeline and the fourth outlet pipeline are energy storage outlets, connected in parallel with each other and connected to the inlet of the first cyclone separator (11); Each inlet pipeline and outlet pipeline is respectively provided with a valve.
10. A supercritical water solar thermal power generation method, implemented by the power generation system according to claim 4, characterized in that: include: Heat absorption cycle: the heat absorber (2) absorbs energy through reflection by the mirror field (1), starts the booster device to boost the water pressure, and the high-pressure water enters the heat absorber (2) to absorb heat and reaches a supercritical state, and then enters the heat exchanger (3) for heat exchange; when the temperature of the high-pressure water after heat exchange cooling is higher than a preset value, it enters the cooling mechanism for cooling, and the cooled high-pressure water enters the heat absorber (2) again for the next round of heat absorption cycle; Energy storage cycle: air enters the heat exchanger (3) to exchange heat with supercritical water, then enters the energy storage and release device (10) to exchange heat with the energy storage medium, the energy storage medium absorbs heat and stores energy, and the air cooled by heat exchange enters the heat exchanger (3) again for the next round of energy storage cycle; Energy release cycle: another air enters the energy storage and release device (10) to absorb heat from the energy storage medium, and then enters the steam generator (14) to release heat. The air cooled by heat exchange enters the energy storage and release device (10) again to carry out the next round of energy release cycle; Power generation cycle: Another high-pressure water absorbs heat through the steam generator (14) and reaches a supercritical state. The supercritical water is supplied to the power generation mechanism to generate electricity and then condensed. The condensed high-pressure water enters the steam generator (14) again for the next round of power generation.