Line focusing photo-thermal storage integrated power generation system

Abstract

The utility model discloses a line focusing photo-thermal storage integrated power generation system, which belongs to the technical field of solar photo-thermal and comprises a double-channel electric auxiliary fused salt energy storage unit and a power generation unit. The double-channel electric auxiliary fused salt energy storage unit comprises a heat release fused salt circulation channel and a heat absorption fused salt circulation channel. The heat release fused salt circulation channel comprises a first hot salt tank, a hot salt pump, a reheater, a superheater, an evaporator, a preheater and a second cold salt tank. The heat absorption fused salt circulation path comprises a first cold salt tank, a first cold salt pump, a line focusing photo-thermal mirror field and a second hot salt tank; the second hot salt tank is connected with the first hot salt tank, the second cold salt tank is connected with the first cold salt tank, and the first cold salt tank is connected with an electric heater; the line focusing photo-thermal mirror field is connected with a salt dredging tank, and the salt dredging tank is connected with the first cold salt tank. According to the line focusing photo-thermal storage integrated power generation system with the structure, decoupling independent operation of the line focusing photo-thermal mirror field and the energy storage unit is achieved, and economic benefits are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of solar thermal energy storage and power generation, and in particular to a linear focusing thermal energy storage integrated power generation system. Background Art

[0002] In the existing trough-type solar thermal power generation technology, the mirror field pipeline uses thermal oil / silicone oil as the fluid circulation medium, the operating temperature does not exceed 400°C, and the energy storage operating temperature range is narrow. To store the same amount of thermal energy, a larger energy storage capacity is required, which will greatly increase the energy storage cost. The main steam temperature of the turbine unit of the solar thermal power generation system using thermal oil / silicone oil is less than 400°C, and the actual turbine efficiency is far less than 40%, and the power generation efficiency is low. The prior art improves the power generation efficiency by setting up heat storage tanks and heat pumps. For example, the patent No. 202120726996.X discloses a solar photovoltaic-thermal hybrid power generation system, but there are still the following disadvantages:

[0003] (1) The solar collector field and thermal energy storage unit cannot achieve decoupled operation. The configuration capacity of thermal energy storage is limited by the area of ​​the solar thermal collector field. It cannot adapt to the deep peak-shaving needs of new wind, solar and energy storage electricity, and its grid friendliness is poor.

[0004] (2) For heat storage through molten salt medium, when the electric field is shut down for a long time or under accident conditions, the molten salt medium solidifies in the pipeline under low temperature conditions, affecting the next use. Utility Model Content

[0005] The purpose of the utility model is to provide a linear focusing solar-thermal-storage integrated power generation system to solve the above technical problems.

[0006] To achieve the above-mentioned purpose, the utility model provides a line-focusing solar-thermal-storage integrated power generation system, comprising a dual-channel electrically-assisted molten salt energy storage unit and a power generation unit connected in sequence;

[0007] The dual-path electrically assisted molten salt energy storage unit comprises an exothermic molten salt circulation path and an endothermic molten salt circulation path;

[0008] The exothermic molten salt circulation path includes a first hot salt tank, a hot salt pump, a reheater, a superheater, an evaporator, a preheater and a second cold salt tank connected in series in sequence;

[0009] The heat-absorbing molten salt circulation path comprises a first cold salt tank, a first cold salt pump, a line-focusing photothermal mirror field and a second hot salt tank which are connected in series in sequence;

[0010] The second hot salt tank is connected to the first hot salt tank, the second cold salt tank is connected to the first cold salt tank, the second cold salt pump on the first cold salt tank is connected to the electric heater and the first electric three-way valve through the second electric three-way valve, the first electric three-way valve is arranged between the hot salt pump and the reheater, and the third electric three-way valve is arranged between the line focusing photothermal mirror field and the second hot salt tank, and the third electric three-way valve is connected to the second cold salt tank;

[0011] The line focusing photothermal mirror field is connected to a salt draining tank, which is connected to the first cold salt tank via a salt draining pump;

[0012] The reheater, superheater, evaporator and preheater are arranged on the power generation unit.

[0013] Preferably, the power generation unit comprises a high-pressure cylinder, a low-pressure cylinder and a generator connected in sequence;

[0014] The high-pressure cylinder and the low-pressure cylinder are both connected to the reheater; the preheater, evaporator, superheater and the high-pressure cylinder are connected in series through a steam pipeline.

[0015] Preferably, the low-pressure cylinder is connected to an air cooler, a low-pressure heater and a deaerator, a condensate pump and a shaft seal heater are provided on the pipeline between the air cooler and the low-pressure heater, and the shaft seal heater is also connected to the air cooler through a bypass pipeline.

[0016] Preferably, the high-pressure cylinder is connected to a high-pressure heater, a water feed pump is provided on the pipeline between the deaerator and the high-pressure heater, the deaerator is respectively connected to the low-pressure heater and the high-pressure heater through a bypass pipeline, and a starting electric heater is provided on the pipeline between the high-pressure heater and the preheater.

[0017] Preferably, the line-focusing thermal mirror field includes several heat collection circuits arranged in parallel; each heat collection circuit includes several heat collection mechanisms arranged in series, the heat collection mechanism includes a bracket, several primary reflectors arranged on the bracket through trackers, a lift is fixed on the bracket, the lift is provided with a secondary reflector, a vacuum heat collection tube is arranged in the secondary reflector, and the vacuum heat collection tubes of adjacent heat collection mechanisms are connected in series.

[0018] Therefore, the utility model adopts a linear focusing solar thermal energy storage integrated power generation system with the above structure, which has the following beneficial effects:

[0019] (1) A dual-channel electrically assisted molten salt energy storage unit is provided and different modes are switched through an electric three-way valve, thereby realizing the decoupling and independent operation of the line-focusing solar thermal mirror field and the energy storage unit, so that solar energy collection, daytime wind and solar energy abandonment and molten salt thermal energy storage can be efficiently combined, thereby improving economic benefits by shaving peaks and filling valleys.

[0020] (2) A salt removal tank and a salt removal pump are provided to remove salt when the equipment is not used for a long time or when a fault occurs, which will not affect the next use and is easy to maintain.

[0021] The technical solution of the utility model is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a structural schematic diagram of Example 1 of a linear focusing solar-thermal-storage integrated power generation system of the utility model;

[0023] Figure 2 This is the distribution diagram of the heat collection mechanism of the utility model;

[0024] Figure 3 This is a schematic diagram of the heat collection mechanism structure of Example 1 of the utility model;

[0025] Figure 4 This is a schematic diagram of the heat collection mechanism structure of Example 2 of the utility model.

[0026] 1. Heat collecting mechanism; 101. Bracket; 102. Primary reflector; 103. Tracker; 104. Secondary reflector; 105. Lifter; 106. Column.

[0027] 201, first cold salt tank; 202, second cold salt tank; 203, first hot salt tank; 204, second hot salt tank; 205, desalting tank; 206, desalting pump; 207, first cold salt pump; 208, second cold salt pump; 209, hot salt pump; 210, electric heater; 211, first electric three-way valve; 212, second electric three-way valve; 213, third electric three-way valve; 214, reheater; 215, superheater; 216, evaporator; 217, preheater; 218, vacuum collector tube.

[0028] 301. High-pressure cylinder; 302. Low-pressure cylinder; 303. Generator; 304. Starting electric heater; 305. Feedwater pump; 306. Deaerator; 307. Low-pressure heater; 308. High-pressure heater; 309. Air cooler; 310. Condensate pump; 311. Shaft seal heater. DETAILED DESCRIPTION

[0029] In the description of the present utility model, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present utility model.

[0030] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Some implementation methods of the present utility model are described in detail below in conjunction with the accompanying drawings.

[0032] Example 1

[0033] like Figure 1 As shown, a line-focusing solar-thermal-storage integrated power generation system includes a dual-channel electrically assisted molten salt energy storage unit and a power generation unit connected in sequence.

[0034] The dual-path electrically assisted molten salt energy storage unit comprises an exothermic molten salt circulation path and an endothermic molten salt circulation path.

[0035] The heat-absorbing molten salt circulation path includes a first cold salt tank 201, a first cold salt pump 207, a line-focusing photothermal mirror field and a second hot salt tank 204 connected in series in sequence. The low-temperature molten salt becomes high-temperature molten salt after passing through the line-focusing photothermal mirror field and is stored in the second hot salt tank 204.

[0036] The exothermic molten salt circulation path includes a first hot salt tank 203, a hot salt pump 209, a reheater 214, a superheater 215, an evaporator 216, a preheater 217 and a second cold salt tank 202 which are sequentially connected in series. The reheater 214, the superheater 215, the evaporator 216 and the preheater 217 are arranged on the power generation unit for generating electricity after heat exchange.

[0037] The second hot salt tank 204 is connected to the first hot salt tank 203, the second cold salt tank 202 is connected to the first cold salt tank 201, the second cold salt pump 208 on the first cold salt tank 201 is connected to the electric heater 210 and the first electric three-way valve 211 through the second electric three-way valve 212, the first electric three-way valve 211 is arranged between the hot salt pump 209 and the reheater 214, and the third electric three-way valve 213 is arranged between the line focusing photothermal mirror field and the second hot salt tank 204, and the third electric three-way valve 213 is connected to the second cold salt tank 202.

[0038] The line focusing photothermal mirror field of this embodiment adopts the existing structure, such as Figure 2-3As shown, the line focusing thermal mirror field includes several heat collecting loops arranged in parallel; each heat collecting loop includes several heat collecting mechanisms 1 arranged in series, the heat collecting mechanism 1 includes a bracket 101, several primary reflectors 102 arranged on the bracket 101 through a tracker 103, the bracket 101 is equipped with a secondary reflector 104 through a column 106, and a vacuum heat collecting tube 218 is arranged in the secondary reflector 104. The vacuum heat collecting tubes 218 of adjacent heat collecting mechanisms 1 are connected in series. The line focusing thermal mirror field is connected to a salt draining tank 205, which is arranged at a low place, and the salt draining tank 205 is connected to the first cold salt tank 201 through a salt draining pump 206. When the power station is shut down for a long time or under accident conditions, the salt draining valve is opened to use the pipeline slope to drain the molten salt in the vacuum heat collecting tube 218 into the salt draining tank 205 by gravity, and then pumped back to the first cold salt tank 201 through the salt draining pump 206.

[0039] The power generation unit includes a high-pressure cylinder 301, a low-pressure cylinder 302 and a generator 303 connected in sequence. The high-pressure cylinder 301 and the low-pressure cylinder 302 are both connected to the reheater 214. The preheater 217, the evaporator 216, the superheater 215 and the high-pressure cylinder 301 are connected in series through a steam pipeline. The low-pressure cylinder 302 is connected to an air cooler 309, a low-pressure heater 307 and a deaerator 306. A condensate pump 310 and a shaft seal heater 311 are arranged on the pipeline between the air cooler 309 and the low-pressure heater 307. The shaft seal heater 311 is also connected to the air cooler 309 through a bypass pipeline. The high-pressure cylinder 301 is connected to a high-pressure heater 308, a feedwater pump 305 is provided on the pipeline between the deaerator 306 and the high-pressure heater 308, the deaerator 306 is respectively connected to the low-pressure heater 307 and the high-pressure heater 308 through a bypass pipeline, and a start-up electric heater 304 is provided on the pipeline between the high-pressure heater 308 and the preheater 217. The start-up electric heater 304 is used to heat the molten salt when it is used for the first time. In this embodiment, the molten salt used is a binary molten salt, the solidification temperature is 290 degrees Celsius, and the maximum heating temperature is 550 degrees Celsius. The temperature is raised by heating the feedwater to prevent the binary molten salt from condensing at the initial stage of startup.

[0040] The specific working process is as follows:

[0041] When the solar irradiance reaches the starting value (in the photovoltaic system, the setting of monitoring sensors such as light intensity sensors, temperature sensors and corresponding controls belongs to the conventional settings of the prior art, and the specific control components and sensor settings are not described in detail here), the first cold salt pump 207 circulates the low-temperature molten salt to the line focusing thermal mirror field through the molten salt pipeline, and the tracking device of the focusing thermal mirror field drives the primary reflector 102 to track the sun in real time, and focuses the solar energy reflected by the primary reflector 102 to the secondary reflector 104. The secondary reflector 104 focuses the light onto the vacuum collector tube 218, and heats the low-temperature molten salt flowing in the vacuum collector tube 218 to high-temperature molten salt. The high-temperature molten salt passes through the diversion of the third electric three-way regulating valve 213, and a part enters the second hot salt tank 204, and a part returns to the second cold salt tank 202 to maintain the cold salt temperature to prevent condensation. When power generation is needed during the day, the hot salt pump 209 transports a portion of the high-temperature molten salt from the first hot salt tank 203 to the reheater 214, the superheater 215, the evaporator 216 and the preheater 217 in sequence. After completing the cascade energy utilization from high-temperature molten salt to low-temperature molten salt, the molten salt temperature drops and returns to the second cold salt tank 202 to complete a cycle.

[0042] The heat input evaporator 216, superheater 215 and reheater 214 drive the high pressure cylinder 301 and low pressure cylinder 302 connected thereto to work respectively, and drive the generator 303 to output electric energy. The residual heat of the steam from the high pressure cylinder 301 after work is completed is used to heat the cold water for the second time through the connected high pressure heater 308, and the steam from the low pressure cylinder 302 after work is condensed into water by the connected air cooler 309. The condensate pump 310 delivers the condensate to the shaft seal heater 311 connected to the air cooler 309 for preliminary heating and then enters the low pressure heater 307. After the first stage of heating by the low pressure heater, the condensate enters the deaerator 306 connected to the low pressure cylinder 302 for heating and deoxidation, and then is heated for the second time by the high pressure heater 308 connected to the high pressure cylinder 301, and is heated for the third time by the preheater 217 for heat exchange with the hot molten salt pipeline, and then enters the evaporator 216 to complete a steam / water power generation cycle.

[0043] The startup electric heater 304 is used to provide hot water to the steam generation system at the initial startup of the unit. Since the heat exchange medium in the steam generation system is binary molten salt, the normal operating temperature range is above 290°C. When the temperature is lower than 290°C, it will gradually solidify. The startup electric heater 304 heats the water to prevent the binary molten salt from condensing at the initial startup.

[0044] The pump body and heater in this embodiment can use the abandoned electricity of photovoltaic power generation or grid electricity, and at the same time realize the function of regulating the grid. When the energy of the line-focusing photothermal mirror field is sufficient, the energy is stored in the hot salt tank for power generation at night to realize the peak-shaving function. When the energy of the line-focusing photothermal mirror field is insufficient, the first cold salt pump 207 maintains a small flow rate and uninterrupted circulation to prevent molten salt condensation. The second molten salt pump is to adjust the flow ratio of the second electric three-way valve 212 and the first electric three-way valve 211 by using the electric heater 210 to achieve the function of temperature adjustment for the energy storage system to prevent the molten salt temperature from being too low or too high.

[0045] The electric heater 210 is powered by the photovoltaic power abandonment during the day, and the photovoltaic power abandonment is recovered by the electric heater 210. At this time, the second cold salt pump 208 is turned on, and the second electric three-way valve 212 and the connection port of the electric heater 210 are opened. The low-temperature molten salt is heated by the electric heater 210 and stored in the hot salt tank to complete the daytime energy storage and output electric energy at night. By shaving the peak and filling the valley, the photovoltaic power abandonment rate during the day is reduced, and the economic benefits are improved.

[0046] Example 2

[0047] The difference between this embodiment and embodiment 1 is that the bracket 101 is installed with the secondary reflector 104 via the lift 105. Figure 4 As shown, when the secondary reflector 104 is subsequently cleaned, the height of the secondary reflector 104 can be lowered, thereby improving the convenience of cleaning.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that they can still modify or replace the technical solution of the utility model with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the utility model.

Claims

1. A linear focusing solar thermal energy storage integrated power generation system, characterized by: It includes a dual-channel electrically assisted molten salt energy storage unit and a power generation unit connected in sequence; The dual-path electrically assisted molten salt energy storage unit comprises an exothermic molten salt circulation path and an endothermic molten salt circulation path; The exothermic molten salt circulation path includes a first hot salt tank, a hot salt pump, a reheater, a superheater, an evaporator, a preheater and a second cold salt tank connected in series in sequence; The heat-absorbing molten salt circulation path comprises a first cold salt tank, a first cold salt pump, a line-focusing photothermal mirror field and a second hot salt tank which are connected in series in sequence; The second hot salt tank is connected to the first hot salt tank, the second cold salt tank is connected to the first cold salt tank, the second cold salt pump on the first cold salt tank is connected to the electric heater and the first electric three-way valve through the second electric three-way valve, the first electric three-way valve is arranged between the hot salt pump and the reheater, and the third electric three-way valve is arranged between the line focusing photothermal mirror field and the second hot salt tank, and the third electric three-way valve is connected to the second cold salt tank; The line focusing photothermal mirror field is connected to a salt draining tank, which is connected to the first cold salt tank via a salt draining pump; The reheater, superheater, evaporator and preheater are arranged on the power generation unit.

2. According to claim 1, a linear focusing solar-thermal-storage integrated power generation system is characterized by: The power generation unit includes a high-pressure cylinder, a low-pressure cylinder and a generator connected in sequence; The high-pressure cylinder and the low-pressure cylinder are both connected to the reheater; the preheater, evaporator, superheater and the high-pressure cylinder are connected in series through a steam pipeline.

3. The linear focusing solar-thermal-storage integrated power generation system according to claim 2 is characterized in that: The low-pressure cylinder is connected to an air cooler, a low-pressure heater and a deaerator. A condensate pump and a shaft seal heater are arranged on the pipeline between the air cooler and the low-pressure heater. The shaft seal heater is also connected to the air cooler through a bypass pipeline.

4. The linear focusing solar-thermal-storage integrated power generation system according to claim 3 is characterized by: The high-pressure cylinder is connected to a high-pressure heater, a water feed pump is arranged on the pipeline between the deaerator and the high-pressure heater, the deaerator is respectively connected to the low-pressure heater and the high-pressure heater through a bypass pipeline, and a starting electric heater is arranged on the pipeline between the high-pressure heater and the preheater.

5. The linear focusing solar-thermal-storage integrated power generation system according to claim 1, characterized in that: The line-focusing thermal mirror field includes a number of heat collection loops arranged in parallel; each heat collection loop includes a number of heat collection mechanisms arranged in series, the heat collection mechanism includes a bracket, a number of primary reflectors arranged on the bracket through a tracker, a lift is fixed on the bracket, the lift is provided with a secondary reflector, a vacuum heat collection tube is arranged in the secondary reflector, and the vacuum heat collection tubes of adjacent heat collection mechanisms are connected in series.

Images