A solid particle heat storage and heat exchange system for heat exchange between a solid and a liquid

Abstract

The present invention discloses a solid particle heat storage and heat exchange system for solid-liquid hybrid heat exchange, which includes a high-temperature particle storage tank, a low-temperature particle storage tank, a high-temperature liquid storage tank, a low-temperature liquid storage tank, a particle disperser, a solid-liquid separator, a heat exchanger, and a particle heating device. The outlets of the high-temperature particle storage tank and the high-temperature liquid storage tank are both connected to the inlet of the particle disperser. The solid particle medium is dispersed in the liquid medium to form a solid-liquid two-phase flow. The solid-liquid two-phase flow in the particle disperser flows through the high-temperature side of the heat exchanger and then enters the solid-liquid separator. The solid-liquid separator is used to separate the solid particle medium and the liquid medium. The separated solid particles enter the low-temperature particle storage tank, and the liquid enters the low-temperature liquid storage tank. The particle storage tank is connected to the inlet of the particle heating device, and the outlet of the particle heating device is connected to the high-temperature particle storage tank. The liquid in the low-temperature liquid storage tank flows through the low-temperature side of the heat exchanger and then enters the high-temperature liquid storage tank.

Description

Technical Field

[0001] The present invention belongs to the field of particle heat storage, and particularly relates to a solid particle heat exchange system for hybrid heat exchange between a solid and a liquid. Background Art

[0002] Renewable energy sources such as wind power and photovoltaic power are restricted by natural conditions such as sunlight and wind, and their power generation capacity fluctuates greatly over time. Energy storage technologies can absorb intermittent and unstable renewable energy and provide various services such as peak shaving, frequency modulation, standby, black start, and demand response support for power grid operation, effectively improving the flexibility, economy, and security of traditional power systems. At the same time, energy storage is the foundation for distributed power and regional micro-energy grids, and also the core foundation of the energy Internet. Therefore, the development of large-scale energy storage technologies is a key link in the transformation of the energy system and the high-quality development of energy.

[0003] Traditional molten salt energy storage technologies use binary molten salts as heat storage media. However, molten salts have the risk of solidification or decomposition at too low or too high temperatures, which not only affects the safe operation of the system but also limits the available temperature difference and affects the system efficiency. In addition, there are also problems such as high molten salt prices and frequent leakage accidents of large molten salt storage tanks. To improve the efficiency of the heat storage system, reduce the heat storage cost, and improve the safety of the heat storage system, it is particularly important to study new heat storage technologies. Summary of the Invention

[0004] In view of the above technical problems, the present invention provides a solid particle heat exchange system for hybrid heat exchange between a solid and a liquid, which uses solid particles as the heat storage medium, greatly reducing the cost of the heat storage system, increasing the heat storage temperature and the available temperature difference, and at the same time dispersing the particles in the liquid during heat exchange, retaining the high-efficiency heat exchange ability of the liquid medium.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A solid particle heat exchange system for hybrid heat exchange between a solid and a liquid, comprising a high-temperature particle storage tank, a low-temperature particle storage tank, a high-temperature liquid storage tank, a low-temperature liquid storage tank, a particle disperser, a solid-liquid separator, a heat exchanger, and a particle heating device.

[0007] The outlet of the high-temperature particle storage tank and the outlet of the high-temperature liquid storage tank are both connected to the inlet of the particle disperser. The solid particle medium is dispersed in the liquid medium to form a solid-liquid two-phase flow. The solid-liquid two-phase flow in the particle disperser flows through the high-temperature side of the heat exchanger and enters the solid-liquid separator.

[0008] The solid-liquid separator is used to separate solid particle medium and liquid medium. After separation, the solid particle medium enters the low-temperature particle storage tank, and the liquid medium enters the low-temperature liquid storage tank. The low-temperature particle storage tank is connected to the inlet of the particle heating device, and the outlet of the heating device is connected to the high-temperature particle storage tank. The low-temperature liquid medium in the low-temperature liquid storage tank flows through the low-temperature side of the heat exchanger and enters the high-temperature liquid storage tank.

[0009] In an embodiment of the present invention, the solid particle heat exchange system further includes a heat pump. The liquid medium flowing out of the solid-liquid separator passes through the low-temperature side of the heat pump and enters the low-temperature liquid storage tank. The liquid flowing out of the low-temperature side of the heat exchanger passes through the high-temperature side of the heat pump and enters the high-temperature liquid storage tank.

[0010] In an embodiment of the present invention, a particle lifting device is provided between the low-temperature particle storage tank and the particle heating device.

[0011] In an embodiment of the present invention, the heat exchanger is a liquid-liquid heat exchanger.

[0012] In an embodiment of the present invention, the solid heat storage particles are any one or a mixture of ceramic particles, silicon carbide particles, quartz sand particles, olivine particles or steel slag particles.

[0013] In an embodiment of the present invention, the liquid medium is liquid metal or molten salt.

[0014] In an embodiment of the present invention, a first regulating valve is provided on the pipeline connecting the high-temperature particle storage tank and the particle disperser, and a first booster pump is provided on the pipeline connecting the particle disperser and the heat exchanger.

[0015] In an embodiment of the present invention, a second regulating valve and a second booster pump are provided on the pipeline connecting the high-temperature liquid storage tank and the particle disperser.

[0016] In an embodiment of the present invention, a third booster pump is provided on the pipeline connecting the solid-liquid separator and the heat pump.

[0017] In an embodiment of the present invention, a third regulating valve and a fourth booster pump are provided on the pipeline connecting the low-temperature liquid storage tank and the heat exchanger.

[0018] Due to the adoption of the above technical solutions, the present invention has the following advantages and positive effects compared with the prior art:

[0019] In the present invention, high-temperature solid particle medium and high-temperature liquid medium are mixed in a particle disperser to form a solid-liquid two-phase flow. Heat is transferred to the low-temperature liquid medium flowing through the liquid side through a heat exchanger. The solid-liquid two-phase on the high-temperature side of the heat exchanger contains solid particles. Due to the collision of the solid particles with the heat exchanger wall, the heat transfer capacity of the heat exchanger can be further improved. Most of the high-temperature liquid after absorbing heat enters the power generation system for power generation or enters the heat supply system for heat supply, and the remaining part enters the high-temperature liquid storage tank as a dispersant for high-temperature particles. Therefore, after heat exchange, the solid-liquid two-phase flow passes through a solid-liquid separator for solid-liquid separation. The separated low-temperature liquid enters the low-temperature liquid storage tank for the next cycle, and the low-temperature solid particles enter the low-temperature particle storage tank. The present invention uses solid particles as the medium for heat storage and heat exchange, utilizes the temperature difference to improve the heat exchange efficiency, and reduces the cost of the heat storage system.

[0020] At the same time, the system needs to operate during power generation or heat supply. The liquid medium only needs to maintain the normal operation of the heat exchanger as a heat exchange medium. Therefore, the amount of liquid used in the system is relatively small, and the scale of the liquid storage tank is much smaller than that of the solid particle storage tank, which also reduces the cost of the heat storage system.

[0021] Furthermore, by dispersing solid particles in a liquid to form a solid-liquid two-phase flow and then performing heat exchange, the solid-liquid two-phase flow passes through the high-temperature side of the heat exchanger, and the liquid passes through the low-temperature side. An ordinary liquid-liquid heat exchanger can be selected, which greatly improves the heat exchange performance of the particles as a heat storage medium, improves the heat exchange efficiency of the heat exchange system, and reduces the cost of the heat exchange system. Description of the Drawings

[0022] Figure 1 It is a schematic flow chart of a solid particle heat storage and heat exchange system for solid-liquid mixed heat exchange according to Embodiment 1 of the present invention.

[0023] Description of the reference numerals: 1 - high-temperature particle storage tank; 2 - first regulating valve; 3 - particle disperser; 4 - first booster pump; 5 - heat exchanger; 6 - solid-liquid separator; 7 - low-temperature particle storage tank; 8 - particle lifting device; 9 - particle heating device; 10 - high-temperature liquid storage tank; 11 - second regulating valve; 12 - second booster pump; 13 - heat pump; 14 - low-temperature liquid storage tank; 15 - third regulating valve; 16 - third booster pump; 17 - fourth booster pump. Detailed Embodiments

[0024] The following further describes in detail a solid particle heat storage and heat exchange system for solid-liquid mixed heat exchange proposed by the present invention with reference to the drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer.

[0025] See Figure 1, a solid particle heat storage and heat exchange system for mixing heat between solid and liquid, which is applied to the field of solar thermal power generation. The liquid medium is molten salt, such as chloride salt or carbonate salt. Of course, the liquid medium can also be liquid metal, including liquid pure metal and liquid alloy, such as liquid pure metal such as liquid sodium, and liquid alloy such as liquid lead-lithium alloy. The solid particle heat storage and heat exchange system therein includes a high-temperature particle storage tank 1, a low-temperature particle storage tank 7, a high-temperature liquid storage tank 10, a low-temperature liquid storage tank 14, a particle disperser 3, a solid-liquid separator 6, a heat exchanger 5, and a particle heating device 9.

[0026] The inlets of the particle disperser 3 are respectively connected to the outlets of the high-temperature particle storage tank 1 and the high-temperature liquid storage tank 10 through pipelines. Solid particles are dispersed in the liquid to form a solid-liquid two-phase flow. The volume dispersion rate of the solid particles in the particle disperser 3 is 15%-30%. The solid-liquid two-phase flow in the particle disperser 3 flows through the high-temperature side of the heat exchanger 5 and enters the solid-liquid separator 6.

[0027] The solid-liquid separator 6 is used to separate the solid particle medium and the liquid medium. The separated solid particle medium enters the low-temperature particle storage tank 7, and the liquid medium enters the low-temperature liquid storage tank 14. The low-temperature particle storage tank 7 is connected to the inlet of the particle heating device 9, and the outlet of the heating device is connected to the high-temperature particle storage tank 1. The low-temperature liquid medium in the low-temperature liquid storage tank 14 flows through the low-temperature side of the heat exchanger 5 and enters the high-temperature liquid storage tank 10.

[0028] When power generation or heat supply is required, the high-temperature particles and high-temperature liquid in the high-temperature particle storage tank 1 respectively enter the particle disperser 3. Solid particles are dispersed in the liquid to form a solid-liquid two-phase flow. The solid-liquid two-phase flow flows into the high-temperature side of the heat exchanger 5 to release heat. The heat-exchanged solid-liquid two-phase flow enters the solid-liquid separator 6. The separated low-temperature liquid enters the low-temperature liquid storage tank 14, and the low-temperature particles enter the low-temperature particle storage tank 7. The low-temperature particles in the low-temperature particle storage tank 7 are heated by the particle heating device 9 and then enter the high-temperature particle storage tank 1.

[0029] The low-temperature liquid in the low-temperature liquid storage tank 14 flows into the low-temperature side of the heat exchanger 5 to absorb heat and increase in temperature. The heated high-temperature liquid enters the power generation system for power generation or enters the heat supply system for heat supply, and the remaining part enters the high-temperature liquid storage tank 10 as a dispersant for high-temperature particles.

[0030] Therefore, on the one hand, in this embodiment, solid particles are used as the heat storage and heat exchange medium. The storage cost of solid particles is lower than that of liquid molten salt. By dispersing the particles in the liquid to form a two-phase flow and then exchanging heat, the problem of poor heat exchange performance of the particles themselves is solved. Further, the solid-liquid two-phase flow exchanges heat with the low-temperature liquid, making the heat exchange process a traditional liquid-liquid heat exchange, greatly improving the heat exchange performance of the particles as the heat storage medium and enhancing the heat exchange efficiency of the heat exchange system. The heat exchanger 5 can adopt a common liquid-liquid heat exchanger 5, further reducing the cost of the heat exchange system.

[0031] Meanwhile, the solid-liquid two-phase flow on the high-temperature side of the heat exchanger 5 contains solid particles, and the heat transfer capacity of the heat exchanger 5 can be further improved due to the collision of the solid particles with the wall surface of the heat exchanger 5.

[0032] On the other hand, in the prior art, the freezing point of the liquid molten salt is below 295 °C and it decomposes above 565 °C, so the available temperature difference is limited. In the present invention, however, the solid particles can be heated to a very high temperature, increasing the heat transfer temperature difference between the solid-liquid two-phase flow and the liquid molten salt in the heat exchanger and enhancing the heat transfer efficiency of the system.

[0033] The solid particle energy storage and heat exchange system further includes a heat pump 13. The liquid medium flowing out of the solid-liquid separator 6 passes through the low-temperature side of the heat pump 13 and enters the low-temperature liquid storage tank 14, and the liquid flowing out of the low-temperature side of the heat exchanger 5 passes through the high-temperature side of the heat pump 13 and enters the high-temperature liquid storage tank 10.

[0034] Since there is always a heat transfer temperature difference in the heat exchanger 5, the temperature of the liquid after heat transfer is inconsistent with the temperature of the liquid in the storage tank. The temperature of the low-temperature liquid separated by the solid-liquid separator 6 is slightly higher than the designed temperature in the low-temperature liquid storage tank 14, and the temperature of the high-temperature liquid after being heated is slightly lower than the temperature of the liquid in the high-temperature liquid storage tank 10. In order to make the temperature of the liquid after heat transfer return to the designed temperature of the liquid storage tank and prevent the system inlet and outlet parameters from continuously changing during the cycle, a part of the heat of the separated low-temperature liquid is transferred to the high-temperature liquid through the heat pump 13, so that the liquid temperature is consistent with the temperature in the liquid storage tank, that is, the low-temperature liquid is consistent with the temperature in the low-temperature liquid storage tank 14, and the high-temperature liquid is consistent with the temperature in the high-temperature liquid storage tank 10.

[0035] The particle heating device 9 can be a solar receiver. The solar receiver can be a solar receiver in a solar thermal power generation system, and a heliostat field is arranged around the solar receiver. The solid particles are heated by solar radiation in the solar receiver. The particle heating device 9 can also be an electric heater.

[0036] A particle lifting device 8 is arranged between the low-temperature particle storage tank 7 and the particle heating device 9. The low-temperature particles in the low-temperature particle storage tank 7 are lifted to the solar receiver by the particle lifting device 8 and are irradiated by solar radiation.

[0037] A first regulating valve 2 is arranged on the pipeline connecting the high-temperature particle storage tank 1 and the particle disperser 3, and a first booster pump 4 is arranged on the pipeline connecting the particle disperser 3 and the heat exchanger 5.

[0038] A second regulating valve 11 and a second booster pump 12 are arranged on the pipeline connecting the high-temperature liquid storage tank 10 and the particle disperser 3.

[0039] A third booster pump 16 is arranged on the pipeline connecting the solid-liquid separator 6 and the heat pump 13.

[0040] A third regulating valve 15 and a fourth booster pump 17 are provided on the pipeline connecting the cryogenic liquid storage tank 14 and the heat exchanger 5.

[0041] When the heat exchange system needs to generate electricity or supply heat, the first regulating valve 2 is opened, and the heat exchange system is started. The high-temperature particles in the high-temperature particle storage tank 1 are dispersed in the high-temperature liquid from the high-temperature liquid storage tank 10 in the particle disperser 3 to form a high-temperature solid-liquid two-phase flow. Subsequently, the high-temperature solid-liquid two-phase flow enters the high-temperature side of the heat exchanger 5 under the action of the first booster pump 4, exchanges heat with the low-temperature liquid from the cryogenic liquid storage tank 14, and the heat-exchanged low-temperature solid-liquid two-phase flow enters the solid-liquid separator 6 to be re-separated into low-temperature solid particles and low-temperature liquid. The low-temperature liquid enters the low-temperature liquid side of the heat pump 13 to further release heat, and then enters the cryogenic liquid storage tank 14 for the next round of circulation; the low-temperature solid particles enter the low-temperature particle storage tank 7. During the day, the low-temperature particles in the low-temperature particle storage tank 7 are lifted to the heat absorber by the particle lifting device 8 to absorb the solar radiation from the heliostat field. The heated high-temperature solid particles then enter the high-temperature particle storage tank 1 for storage.

[0042] The low-temperature liquid absorbs heat and increases in temperature after heat exchange in the heat exchanger 5. The heated high-temperature liquid enters the high-temperature liquid side of the heat pump 13 to further absorb heat. Subsequently, most of the high-temperature liquid enters the power generation system to generate electricity or enters the heat supply system to supply heat, and the remaining part enters the high-temperature liquid storage tank 10 as a dispersant for high-temperature particles. Therefore, the liquid medium only operates when the system needs to generate electricity or supply heat, and the liquid as a heat exchange medium only needs to maintain the normal operation of the heat exchanger, so the liquid consumption in the system is relatively small, and the scale of the liquid storage tank is much smaller than that of the solid particle storage tank.

[0043] The high-temperature solid particles and the high-temperature liquid in the high-temperature liquid storage tank 10 can have the same temperature, or the temperature of the high-temperature particles can be slightly higher than that of the high-temperature liquid. The solid particles should have good high-temperature resistance, be chemically stable at high temperatures, and be inexpensive. Their shapes can be spherical, ellipsoidal or other shapes. Preferred solid particles include ceramic particles, silicon carbide particles, quartz sand particles, olivine particles or steel slag particles.

[0044] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalent technologies, they still fall within the protection scope of the present invention.

Claims

1. A solid particle heat storage and heat exchange system for heat exchange between a solid and a liquid, characterized in that, It includes a high-temperature particle storage tank, a low-temperature particle storage tank, a high-temperature liquid storage tank, a low-temperature liquid storage tank, a particle disperser, a solid-liquid separator, a heat exchanger, and a particle heating device. The outlet of the high-temperature particle storage tank and the outlet of the high-temperature liquid storage tank are both connected to the inlet of the particle disperser. Solid particle medium is dispersed in the liquid medium to form a solid-liquid two-phase flow. The solid-liquid two-phase flow in the particle disperser flows through the high-temperature side of the heat exchanger and enters the solid-liquid separator. The solid-liquid separator is used to separate the solid particle medium and the liquid medium. The separated solid particle medium enters the low-temperature particle storage tank, and the liquid medium enters the low-temperature liquid storage tank. The low-temperature particle storage tank is connected to the inlet of the particle heating device, and the outlet of the particle heating device is connected to the high-temperature particle storage tank. The liquid medium in the low-temperature liquid storage tank flows through the low-temperature side of the heat exchanger and enters the high-temperature liquid storage tank.

2. The solid particle heat storage and heat exchange system for solid-liquid mixed heat exchange according to claim 1, wherein The solid particle heat exchange system further includes a heat pump. The liquid medium flowing out of the solid-liquid separator passes through the low-temperature side of the heat pump and enters the low-temperature liquid storage tank. The liquid flowing out of the low-temperature side of the heat exchanger passes through the high-temperature side of the heat pump and enters the high-temperature liquid storage tank.

3. The solid particle heat storage and heat exchange system for solid-liquid hybrid heat exchange according to claim 1, wherein A particle lifting device is provided between the low-temperature particle storage tank and the particle heating device.

4. The solid particle heat storage and heat exchange system for solid-liquid hybrid heat exchange according to claim 1, characterized in that, The heat exchanger is a liquid-liquid heat exchanger.

5. The solid particle heat storage and heat exchange system for solid-liquid hybrid heat exchange according to claim 1, characterized in that, The solid particle medium is any one of ceramic particles, silicon carbide particles, quartz sand particles, olivine particles, or steel slag particles.

6. The solid particle heat storage and heat exchange system for solid-liquid mixed heat exchange according to claim 1, characterized in that, The liquid medium is liquid metal or molten salt.

7. The solid particle heat storage and heat exchange system for heat exchange between solid and liquid according to claim 1, wherein A first regulating valve is provided on the pipeline connecting the high-temperature particle storage tank and the particle disperser, and a first booster pump is provided on the pipeline connecting the particle disperser and the heat exchanger.

8. The solid particle heat storage and heat exchange system for solid-liquid mixed heat exchange according to claim 1, wherein A second regulating valve and a second booster pump are provided on the pipeline connecting the high-temperature liquid storage tank and the particle disperser.

9. The solid particle heat storage and heat exchange system for heat exchange between solid and liquid according to claim 2, wherein A third booster pump is provided on the pipeline connecting the solid-liquid separator and the heat pump.

10. The solid particle heat storage and heat exchange system for solid-liquid hybrid heat exchange according to claim 1, characterized in that, A third regulating valve and a fourth booster pump are provided on the pipeline connecting the low-temperature liquid storage tank and the heat exchanger.

Images