Molten salt tank type heat collection device, operation method thereof and molten salt tank type photo-thermal power station

Abstract

The invention relates to a molten salt groove type heat collecting device, an operation method of the molten salt groove type heat collecting device and a molten salt groove type photo-thermal power station, and belongs to the field of molten salt groove type photo-thermal power stations. The heat collection mechanism comprises a plurality of heat collectors which are connected in series through pipelines to form a heat collector group, and the two ends of the heat collector group are communicated to the molten salt tank; the heat collector set is arranged in a U shape, a pipeline at the bottom of the U shape is a middle jumper pipe, and the middle jumper pipe is located at the highest position. And a gas outlet of the gas heating mechanism is communicated with the middle jumper pipe. The two ends of the U-shaped heat collector set are communicated with the fused salt tank, the highest position of the heat collector set is communicated with the gas heating mechanism, heating and salt injection can be conveniently conducted on the heat collectors, the automation degree is high, and convenience and rapidness are achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of molten salt tank type photo-thermal power stations, and particularly relates to a molten salt tank type heat collecting device, an operation method thereof and a molten salt tank type photo-thermal power station. BACKGROUND

[0002] With the increasingly serious global energy crisis and environmental pollution, building a new power system mainly based on new energy is an important measure for China to promote energy transformation and achieve the dual-carbon policy goal. Photo-thermal power stations have large-scale heat storage systems and can provide rotational inertia, and are the main part of the new power system. The existing photo-thermal technology routes mainly include tank type, tower type, linear Fresnel type and dish type, among which the tank type photo-thermal power station is the most mature technology route. In order to reduce the power generation cost, simplify the process system and improve the power generation efficiency, the molten salt tank type photo-thermal power station is developed and popularized. However, the preheating and salt injection technology of the heat collecting pipe of the molten salt tank type photo-thermal power station has not been maturely applied. The heat conducting oil tank type photo-thermal power station with similar structure has a working medium of heat conducting oil, and the medium temperature is about 60 DEG C during oil injection, so preheating of the heat collecting pipe is not required. In addition, oil injection is only required during the first operation or maintenance, and oil discharge is not required during normal operation, so the automation degree of the oil injection process is low.

[0003] Therefore, it is necessary to develop equipment and methods related to the preheating and salt injection of the heat collecting pipe of the molten salt tank type photo-thermal power station. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the application is to provide a molten salt tank type heat collecting device, an operation method thereof and a molten salt tank type photo-thermal power station, which can preheat and inject salt into the heat collecting pipe of the molten salt tank type photo-thermal power station, are convenient and efficient, and have high efficiency.

[0005] In a first aspect, the application provides a molten salt tank type heat collecting device, which comprises:

[0006] A molten salt tank for containing molten salt;

[0007] A heat collecting mechanism comprising a plurality of series-connected heat collectors connected by pipelines, forming a heat collector group, both ends of the heat collector group being communicated to the molten salt tank; the heat collector group is arranged in a U shape, and the pipeline at the bottom of the U shape is provided as a middle cross pipe, the middle cross pipe being at the highest position;

[0008] A gas heating mechanism, the gas outlet of which is communicated to the middle cross pipe.

[0009] Further, the heat collecting mechanism further comprises a plurality of driving devices, each of which drives one of the heat collectors to rotate around the shaft.

[0010] Further, the molten salt tank is connected with a venting pipeline, and a venting control valve is arranged on the pipeline connecting the heat collector group and the gas outlet.

[0011] Further, the gas heating mechanism comprises a compressor and a gas heat accumulator, the outlet of the compressor is communicated with the gas heat accumulator, and the gas outlet is communicated with the outlet of the gas heat accumulator.

[0012] Further, the gas heat accumulator is provided with a solid heat storage device or an electric heater.

[0013] In the second aspect of the present application, an operation method applied to the above-mentioned molten salt tank type heat collector device is provided, which comprises the following steps:

[0014] The heat collector preheating process comprises focusing sunlight on the heat collector, and feeding gas into the heat collector group through the intermediate cross-pipe by the gas heating mechanism until the temperature of all the heat collectors reaches a first preset temperature.

[0015] Further, the heat collector preheating process further comprises adjusting the driving device to drive the heat collector to rotate around the shaft so that the heat collector is rotated to a position for focusing sunlight.

[0016] Further, the effective solar radiation of the heat collector is detected, and the defocusing angle of the heat collector is adjusted to control the temperature rising rate of the heat collector.

[0017] Further, the method further comprises a salt injection process after the temperature of all the heat collectors reaches the preset temperature, and the salt injection process comprises the following steps:

[0018] The molten salt is injected from the molten salt tank into the heat collector group until all the heat collectors are filled with molten salt.

[0019] Further, the molten salt in the molten salt tank is injected from one end of the heat collector group, and when the temperature at the intermediate cross-pipe reaches a second preset temperature, the venting control valve on the pipeline connecting the intermediate cross-pipe to the gas heating mechanism is closed, so that the molten salt flows out from the other end of the heat collector group to the salt tank.

[0020] In the third aspect of the present application, a molten salt tank type photo-thermal power station is provided, which comprises the above-mentioned molten salt tank type heat collector device or the molten salt tank type heat collector device operated according to the above-mentioned operation method.

[0021] The present application has the following advantages:

[0022] The two ends of the U-shaped heat collector group are communicated with the molten salt tank, and the highest position of the intermediate cross-pipe of the heat collector group is communicated with the gas heating mechanism, so that the heat collector can be heated and salted conveniently, and the automation degree is high, which is convenient and fast.

[0023] By injecting high-temperature and high-pressure gas, the axial temperature uniformity of the heat collector during preheating can be ensured, and the thermal stress of the heat collector can be reduced.

[0024] By controlling the defocusing angle of the heat collector, the temperature rise rate of the heat collector tube can be controlled, and the light resources can be fully utilized on the basis of ensuring the safety of the system. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated herein and constitute a part of the detailed description. It will be readily understood that the drawings are merely included to clarify the present application and are presented for purposes of illustration only. Obviously, other drawings can be obtained by those skilled in the art based on these drawings.

[0026] Figure 1 The structure of the molten salt tank type heat collecting device of the present application is shown in the figure.

[0027] Figure 2 The structure of the heat collector of the present application is shown in the figure.

[0028] Reference signs:

[0029] 1, cold salt tank; 2, cold salt pump; 3, hot salt tank; 4, self-circulation control valve; 5, mirror field removal control valve; 6, heat collection loop temperature measuring point; 7, heat collector; 8, vent control valve; 9, vent line temperature measuring point; 10, vent line control valve; 11, gas inlet control valve; 12, gas heating device; 13, compressor; 14, compressed air control valve; 15, cold salt tank inlet control valve; 16, hot salt tank inlet control valve; 17, hydraulic drive device or motor drive device; 18, drive column; 19, local control box; 20, jumper pipe; 21, salt discharge tank inlet control valve; 22, salt discharge tank; 23, salt discharge pump; 24, salt discharge tank salt injection control valve; 25, salt discharge tank cold tank removal control valve. DETAILED DESCRIPTION

[0030] In order for those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0031] In addition, in the following description, the description of well-known structures and techniques is omitted to avoid unnecessary confusion of the concepts disclosed in the present application.

[0032] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance. The terms "mounting", "connecting", "connecting" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0033] The exemplary embodiments will be described in detail hereinbelow, examples of which are shown in the drawings. When the following description refers to the drawings, identical numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments are not meant to represent all implementations consistent with the present application. Rather, they are merely examples of methods and systems consistent with some aspects of the present application as detailed in the appended claims.

[0034] The present application provides a molten salt tank type heat collecting device, an operating method thereof and a molten salt tank type photo-thermal power station, which solve the problem that there is no mature application of the preheating and salt injection technology of the heat collecting pipe of the molten salt tank type photo-thermal power station.

[0035] The molten salt tank type heat collecting device provided by the present application comprises:

[0036] The molten salt tank type heat collecting device provided by the present application comprises:

[0037] The heat collecting mechanism comprises a plurality of heat collectors 7 connected in series, which form a heat collector group, both ends of the heat collector group being communicated to the molten salt tank; the heat collector group is arranged in a U shape, and the pipeline at the bottom of the U shape is provided with a middle cross pipe 20, the middle cross pipe 20 being at the highest position;

[0038] The gas heating mechanism is provided with a gas outlet communicated to the middle cross pipe 20.

[0039] The application adopts a U-shaped collector group, that is, a plurality of collectors 7 are connected in series through pipes and arranged in two parallel rows, wherein all the collectors 7 are located on the two side edges of the U shape, the middle section pipe is provided as a middle cross pipe 20, the two ends of the collector group are connected to molten salt tanks, and the middle cross pipe 20 is the highest position of the collector group and is connected to a gas heating mechanism, so that the collectors 7 can be conveniently heated and salted, and the degree of automation is high, which is convenient and fast.

[0040] The molten salt in the molten salt tank is generally a plurality of salts mixed and melted, such as a molten body of alkali metal or alkaline earth metal halide, nitrate, sulfate, etc.; the molten salt is a molten body composed of metal cations and non-metal anions. In the application, the molten salt is mainly used for heat transfer and heat storage, and generally absorbs solar energy and stores heat energy.

[0041] The collector mechanism of the application adopts a collector group in which a plurality of collectors 7 are connected in series, and the two ends are connected to molten salt tanks, so that the molten salt in the molten salt tank can be injected into the collectors 7; wherein the flow injection of the molten salt is completed by a liquid pump.

[0042] The temperature of the molten salt is usually very high, reaching above 245 DEG C, and usually 280 DEG C. The heat collecting tube of the collector 7 needs to be preheated before the molten salt is injected, otherwise the heat collecting tube will burst due to thermal shock. The preheating of the collector 7 is mainly completed by focusing sunlight, but due to the uneven preheating of the plurality of collectors 7, the application adopts a gas heating mechanism to inject high-temperature gas into the collector group to ensure that the temperature of all the collectors 7 reaches uniformity before the molten salt is injected, so as to avoid the safety of subsequent molten salt injection.

[0043] Among them, the middle cross pipe 20 of the collector group is provided as the highest position, the collectors 7 on the two sides are provided vertically or obliquely or horizontally, and the two ports of the collector group are connected to the molten salt tanks. The middle cross pipe 20 of the collector group is connected to the gas outlet of the gas heating mechanism, the high-temperature gas sent into the collector group through the gas outlet, and the high-temperature gas passes through the collectors 7 in sequence, so as to realize the uniformity of the axial temperature of the collectors 7 and reduce the temperature difference.

[0044] In actual operation, a temperature detector can be arranged at the two ends of the collector group. As long as the temperature display at this position reaches the set temperature (equal to or close to the temperature of the molten salt), it indicates that the preheating of the collector 7 is completed.

[0045] Further, the collector mechanism further comprises a plurality of driving devices, each of which drives one of the collectors 7 to rotate around the shaft.

[0046] For the preheating of the heat collector 7, the application also adopts a driving device capable of driving the heat collector 7 to rotate, so as to adjust the defocusing angle of the heat collector 7, focus the sunlight at a suitable angle, control the temperature speed of the heat collecting tube, quickly realize the preheating of the heat collector 7, and improve the preheating efficiency.

[0047] Further, the molten salt tank is connected with a venting pipeline, the heat collector 7 group is provided with a venting control valve 8 on the pipeline connected with the gas outlet, and the venting pipeline is communicated to the pipeline between the venting control valve 8 and the gas outlet.

[0048] For the preheating of the heat collector 7 and the structure of injecting molten salt, the application adopts a venting pipeline to communicate the molten salt tank and the gas outlet, and corresponding control valves are matched and arranged on the connecting pipeline to realize different operation processes of preheating and molten salt injection.

[0049] When the preheating of the heat collector 7 is completed, the heat collector 7 is filled with high-temperature gas, and when the molten salt is injected into the heat collector 7, the gas needs to be discharged. The application discharges the gas to the molten salt tank through the venting pipeline, and the venting control valve 8 needs to be closed after the heat collector 7 is filled with molten salt. In this way, the heat collector 7 can be injected with molten salt in time after preheating, the operation interval of the two processes is shortened, the degree of automation is high, and the production efficiency is improved.

[0050] Further, the gas heating mechanism comprises a compressor 13 and a gas heat accumulator, the outlet of the compressor 13 is communicated with the gas heat accumulator, and the gas outlet is communicated with the outlet of the gas heat accumulator.

[0051] The gas heating mechanism adopted by the application is realized by combining the compressor 13 with the gas heat accumulator. The high-temperature and high-pressure gas discharged from the compressor 13 is buffered by the gas heat accumulator, so as to play a buffering pulsation role.

[0052] The high-temperature and high-pressure gas generated by the gas heating mechanism is introduced into the heat collector 7, so as to ensure the uniformity of the axial temperature of the heat collecting tube and reduce the temperature difference. A temperature sensor can be arranged at the gas outlet of the gas heating mechanism, the outlet temperature can be adjusted according to the temperature of the heat collecting tube, and the thermal stress of the heat collecting tube can be avoided.

[0053] Further, the gas heat accumulator is provided with a solid heat storage device or an electric heater.

[0054] The application can also be provided with a solid heat storage device in the gas heat accumulator, that is, the heat is absorbed by rocks, metals, concrete and the like, the temperature is increased, and the heat is stored. Or an electric heater is arranged to further heat the gas. Both can exist at the same time and run synchronously.

[0055] The second aspect of the application provides an operation method of the molten salt tank type heat collector device as described above, which comprises the following steps.

[0056] The preheating process of the solar collectors includes the solar collectors focusing sunlight, and the gas heating mechanism sending gas into the solar collector group through the intermediate cross pipe 20 until the temperature of all the solar collectors 7 reaches the first preset temperature.

[0057] Before injecting molten salt, collector 7 must be preheated to reach or approach the temperature of the molten salt. In this invention, the preheating of collector 7 is mainly accomplished by focusing sunlight. However, in actual applications, the number of collectors 7 in the collector group is large, and there are differences in the manufacturing, installation, and tracking accuracy of each device, resulting in differences in the photothermal efficiency of collector 7. Therefore, it cannot be guaranteed that the temperature of all collectors 7 is consistent. In this invention, a gas heating mechanism is used to introduce high-temperature gas into the collector group to achieve axial temperature uniformity of the collector group until the temperature of all collectors 7 reaches a first preset temperature. This first preset temperature is not lower than the temperature at which the molten salt solidifies.

[0058] Furthermore, the preheating process of the solar collector 7 also includes adjusting the driving device to drive the solar collector 7 to rotate around the axis, so that the solar collector 7 rotates to a preset position for focusing sunlight.

[0059] The preheating of collector 7 is mainly achieved by using external sunlight. By adjusting the drive device, the collector tube can reach the optimal irradiation angle to absorb more solar energy, reduce preheating time, and improve preheating efficiency.

[0060] Furthermore, the effective solar radiation of the collector 7 is detected, and the defocusing angle of the collector is adjusted to control the temperature rise rate of the collector.

[0061] In this invention, each solar collector 7 is equipped with a corresponding driving device. By detecting the effective solar radiation of each solar collector 7 and adjusting the defocusing angle of the solar collector 7, the temperature rise rate of the solar collector 7 can be controlled.

[0062] Furthermore, it also includes a salt injection process after all collectors have reached a preset temperature, the salt injection process comprising:

[0063] Molten salt is injected from the molten salt tank into the collector group until all the collectors 7 are filled with molten salt.

[0064] The process of injecting molten salt into the collector 7 is carried out after the temperature measuring point 6 of the collector 7 reaches the preset temperature. At this time, the gas supply needs to be stopped and the gas inlet control valve 11 needs to be closed. The molten salt in the molten salt tank flows into the collector 7 through the liquid pump to ensure that the molten salt only flows along the collector 7 until all the collectors 7 are filled with molten salt.

[0065] Furthermore, molten salt is injected into the molten salt tank from one end of the solar collector assembly. When the temperature at the intermediate cross-connector 20 reaches the second preset temperature, the vent control valve 8 on the pipeline connecting the intermediate cross-connector 20 to the gas heating mechanism is closed, so that the molten salt flows out to the molten salt tank through the other end of the solar collector assembly.

[0066] The process of injecting molten salt into the collector 7 from the molten salt tank involves the salt entering from one end of the collector group and flowing out from the other end back to the molten salt tank. Since there is gas in the collector 7, it needs to be discharged during the injection of molten salt. In this invention, the gas on one side of the U-shaped collector group is discharged through a venting pipe. At this time, the temperature at the intermediate cross pipe 20 is detected. When the second preset temperature is reached, the venting control valve 8 of the pipe connecting the intermediate cross pipe 20 to the gas heating mechanism is closed, so that the injected molten salt flows out through the other side, realizing the salt injection of the entire collector group.

[0067] A third aspect of the present invention provides a molten salt trough solar thermal power plant, comprising a molten salt trough heat collector as described above, or a molten salt trough heat collector operated in accordance with the operating method described above.

[0068] This invention relates to a molten salt trough solar thermal power plant, comprising a trough collector 7 and a control system, a cold salt tank 1, a hot salt tank 3, a salt pump, a gas heating structure, a salt discharge tank 22, pipeline-related valves and instruments, etc. (See also...) Figure 1 The structural relationships are shown.

[0069] The present invention uses a cold salt tank 1 and a salt discharge tank 22 arranged in parallel as molten salt tanks; while the hot salt tank 3 is used to store high-temperature molten salt, which is generally used only when the solar thermal power plant is operating normally.

[0070] The operation process of this invention is described in detail below:

[0071] 1. Preheating of the heat collection tubes:

[0072] 1.1 When sunrise begins in the morning and a clear day is predicted, preheating of the collector tubes can be prepared. First, open the inlet control valve 15 of the cold salt tank 1 and / or the inlet control valve 21 of the salt discharge tank 22, the vent control valve 8 of all collector circuits, and the air intake control valve 11.

[0073] 1.2 The local control box 19 (LOC) controls the hydraulic drive device or the motor drive device 17 to drive the solar collector 7 (SCA) to start focusing and collecting heat, and the solar collector tubes start to heat up;

[0074] 1.3 Open the compressed air control valve 14, start the compressor 13 and the gas heating device 12, and introduce high-temperature and high-pressure gas into the heat collection circuit to ensure uniform axial temperature of the heat collection tube and reduce temperature difference.

[0075] 1.4. Based on the algorithm model for predicting the internal temperature of the heat collector tube using the temperature measuring points at the inlet and outlet of the heat collector tube, determine the overall temperature and temperature rise rate of the heat collector tube.

[0076] 1.5. Based on the PID control algorithm of the collector tube temperature rise rate, DII (Solar Effective Radiation), and SCA defocusing angle, the collector tube is controlled to rise at the required temperature rise rate. The relationship between the three is as follows:

[0077] C·m·(ΔT / Δt)=DII·A·η·ζ·λ·L·Ψ-Ф

[0078] Where: C—specific heat capacity of the heat collector tube

[0079] m—mass of a single-loop heat collector tube

[0080] ΔT—Temperature change of the heat collector tube

[0081] Δt—Temperature change time of the heat collector tube: ΔT / Δt represents the rate of temperature rise of the heat collector tube;

[0082] DII—Effective Solar Radiation

[0083] A—Heat collector area

[0084] η—Reflector integrity rate (1-Reflector breakage rate)

[0085] ζ — Optical efficiency, a fixed value for the device

[0086] λ—cleaning factor

[0087] L-LOC utilization rate

[0088] Ψ—Efficiency of spillover loss caused by focus angle; for multiple SCAs, the average value is calculated.

[0089] Ф—Heat loss from heat collector tube

[0090] When the effective solar radiation (DII) is known, the temperature rise rate of the heat collector tube can be controlled by changing the SCA defocusing angle.

[0091] Special Note:

[0092] A. The highest point of each heat collection loop should be located at the intermediate cross-connection 20 to facilitate salt discharge. Vent lines are set at the highest point of the cross-connection and connected to the cold salt tank 1 or the salt discharge tank 22 and the gas heating device respectively. Each vent line is equipped with a vent control valve 8.

[0093] B. A single solar collector circuit contains multiple solar collectors. Each solar collector is equipped with a hydraulic drive device or a motor drive device 17 and a local control box 19 at the middle drive column 18. The position of the solar collector can be changed by controlling the hydraulic drive device or the motor drive device 17 through the local control box 19.

[0094] C. The gas heating device 12 can be a solid heat storage device or an electric heater. It heats the gas by absorbing off-peak electricity, abandoned electricity, etc., and generates high-temperature and high-pressure gas, which then enters the heat collection pipe. The high-temperature gas can reduce the thermal shock of the heat collection pipe and prevent damage to the heat collection pipe.

[0095] D. The outlet temperature of the gas heating device 12 should be adjusted according to the temperature of the heat collection tube to avoid thermal stress on the heat collection tube.

[0096] 2. Automated salt injection process for the mirror field:

[0097] 2.1 When the temperature of all heat collection circuit temperature measuring points 6 exceeds the preset temperature value, close the inlet control valve 11, close the compressor 13, gas heating device 12 and compressed air control valve 14, keep the vent control valve 8 open, and then open the vent pipeline control valve 10.

[0098] 2.2 After the collector tube is preheated to the required temperature, close the salt discharge tank inlet control valve 21, start a cold salt pump 2 at the minimum speed, slowly open the mirror field control valve 5, and slowly start injecting salt into the collector tube at the minimum flow rate; alternatively, start a salt discharge pump 23 at the minimum speed, slowly open the salt discharge tank salt injection control valve 24, and slowly start injecting salt into the collector tube at the minimum flow rate.

[0099] There are two salt injection paths: one is from the salt discharge tank 22 through the salt discharge pump 23, controlled by valve 24, the molten salt is slowly injected into the solar collector 7, and returns to the cold salt tank 1 through the cold salt tank inlet control valve 15. The second method is from the cold salt tank 1 through the cold salt pump 2, controlled by the mirror field control valve 5, the molten salt is slowly injected into the solar collector 7, and returns to the cold salt tank 1 through the cold salt tank inlet control valve 15.

[0100] 2.3 During the salt injection process, the liquid pump flow rate should be automatically adjusted according to the temperature measurement point 6 of the heat collection circuit to control the temperature change rate of the heat collection circuit within a certain range, so as to prevent thermal shock or solidification of molten salt.

[0101] 2.4 The location of salt injection can be determined by multiple temperature measuring points 6 of the heat collection loop arranged on the loop. When the temperature of the venting pipeline temperature measuring point 9 rises to the cold salt temperature, the corresponding venting control valve 8 can be closed. The venting control valve 8 is open before salt injection to discharge the gas in the pipeline. When it is determined by the venting pipeline temperature measuring point 9 that the upstream pipeline has been filled with molten salt medium, the venting control valve 8 can be closed.

[0102] 2.5 When all the venting pipeline temperature measuring points 9 of the heat collection circuits reach the cold salt temperature and the corresponding venting control valves are closed, then close the venting pipeline control valve 10.

[0103] 2.6 When all temperature measuring points on all pipelines from the collector circuit to the cold salt tank reach the cold salt temperature, it indicates that the salt injection is complete and the collector focusing can begin. Close the cold salt tank inlet control valve 15 and open the hot salt tank inlet control valve 16.

[0104] The present invention has the following beneficial effects:

[0105] 1. This method has a high degree of automation in the preheating and salt injection processes, making it convenient and fast;

[0106] 2. When light resources fluctuate, the temperature rise rate of the heat collection tube is controlled by adjusting the focusing angle of the heat collector, so as to make full use of light resources while ensuring system safety.

[0107] 3. During preheating, high-temperature compressed air is used to purge the heat collection tubes, which can ensure uniform axial temperature of the heat collection tubes and reduce thermal stress on the heat collection tubes.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A molten salt tank type heat collection device, characterized in that, include: Molten salt vessel, used to hold molten salt; The heat collection mechanism includes multiple series-connected heat collectors (7) forming a heat collector group, both ends of which are connected to the molten salt tank; the heat collector group is arranged in a U-shape, and the pipe at the bottom of the U-shape is set as an intermediate cross pipe (20), which is at the highest position. A gas heating mechanism, the gas outlet of which is connected to the intermediate cross-connector (20).

2. The molten salt tank type heat collection device according to claim 1, characterized in that, The heat collection mechanism also includes multiple driving devices, each of which drives one of the heat collectors (7) to make the heat collector (7) rotate around an axis.

3. The molten salt tank type heat collection device according to claim 1 or 2, characterized in that, The molten salt tank is connected to a venting pipeline, and a venting control valve (8) is provided on the pipeline connecting the solar collector group and the gas outlet; the venting pipeline is connected to the pipeline between the venting control valve (8) and the gas outlet.

4. The molten salt tank type heat collection device according to claim 1, characterized in that, The gas heating mechanism includes a compressor (13) and a gas storage tank. The outlet of the compressor (13) is connected to the gas storage tank, and the gas outlet is connected to the outlet of the gas storage tank.

5. The molten salt tank type heat collection device according to claim 4, characterized in that, The gas heat storage device is equipped with a solid heat storage device or an electric heater.

6. An operating method for a molten salt trough-type solar collector, applied to the molten salt trough-type solar collector as described in any one of claims 1-5, characterized in that, include: The preheating process of the solar collectors includes the solar collectors (7) focusing sunlight, and the gas heating mechanism sending gas into the solar collector group through the intermediate cross pipe (20) until the temperature of all the solar collectors (7) reaches the first preset temperature.

7. The operating method according to claim 6, characterized in that, The preheating process of the solar collector (7) also includes adjusting the driving device to drive the solar collector (7) to rotate around the axis, so that the solar collector (7) rotates to a preset position for focusing sunlight.

8. The operating method according to claim 7, characterized in that, The effective solar radiation of the solar collector is detected, and the focusing angle of the solar collector is adjusted to control the rate of temperature rise of the solar collector.

9. The operating method according to claim 7 or 8, characterized in that, It also includes a salt injection process after all collectors have reached a preset temperature, the salt injection process comprising: Molten salt is injected from the molten salt tank into the collector group until all the collectors (7) are filled with molten salt.

10. The operating method according to claim 9, characterized in that, Molten salt is injected into the molten salt tank from one end of the solar collector group. When the temperature at the intermediate cross-connector (20) reaches the second preset temperature, the vent control valve (8) on the pipeline connecting the intermediate cross-connector (20) to the gas heating mechanism is closed so that the molten salt flows out to the molten salt tank through the other end of the solar collector group.

11. A molten salt bath solar thermal power plant, characterized in that, Includes the molten salt trough type heat collector as described in any one of claims 1-5, or the molten salt trough type heat collector operated according to the operating method described in any one of claims 6-10.

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