System and method for testing preheating performance of frozen fused salt heat absorber of photo-thermal power station
By designing a test system for the preheating performance of the molten salt heat absorber of the photothermal power station after icing, the safety of the heat absorber pipe during the preheating process after icing is solved, and data support and optimization solutions are provided to ensure the safety and efficiency of the preheating process.
Patent Information
- Application Number
- CN202510575516.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-06
- Publication Date
- 2025-08-01
AI Technical Summary
In the prior art, there is a huge temperature gradient and thermal stress during the preheating process of the molten salt heat absorber of the photothermal power station after icing, which may cause the heat absorbing pipe to bend, deform or rupture, affecting the operation safety of the photothermal power station, and lack effective testing systems and methods to evaluate the preheating performance under icing conditions.
A test system for the preheating performance of molten salt heat absorbers in the photothermal power station was designed, including a support frame, molten salt heat absorber tube screen simulator, thermocouple wire set, data collector, simulated photothermal source, water storage tank and heat flow measurement device. By simulating the preheating process under different icy conditions, the temperature distribution and thermal stress are recorded, and data support and guidance are provided.
The test system can fully reflect the overall preheating effect of the pipe screen, provide data support and guidance, help optimize the preheating process, ensure that the preheating speed and pipe wall stress are within a safe range, and avoid damage to the heat absorbing pipe.
Smart Images
Figure CN120404203A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of solar thermal power generation, and particularly to a test system and method for the preheating performance of a molten salt absorber in a solar thermal power station after icing. Background Art
[0002] Molten salt tower solar thermal power generation is the mainstream technical route of current tower solar thermal power generation technology. As a key component in this system, the molten salt absorber usually adopts the form of a tubular absorber. In a solar thermal power station, the solar energy concentrated by the heliostat field irradiates on the absorber, and the molten salt medium in the absorber absorbs this part of energy, and then exchanges heat with water in the subsequent process to generate superheated steam, which then drives the steam turbine to do work and generate electricity, thereby realizing the conversion of solar energy into electrical energy.
[0003] The freezing point of the most widely used molten salt Solar Salt in molten salt tower solar thermal power stations is about 210 °C. To reduce heat loss and prevent the molten salt from solidifying in the absorber, the molten salt in the absorber should be drained at night when there is no sunlight, and then recharged during the day when there is sunlight. To ensure that the molten salt does not solidify and block during recharging, the absorber must be preheated. When preheating, a part of the heliostat field is called to provide a lower incident heat flux to the front of the absorber, and the tube wall temperature of the entire absorber is gradually heated above the freezing point of the molten salt. Generally speaking, the molten salt absorber of a solar thermal power station is equipped with an electric tracing system, and a thermal insulation system is installed on the back. Under normal circumstances, icing on the outside of the tube wall will not occur during the preheating the next day. However, in an extremely low temperature environment or under the condition of a failure of the electric tracing system, icing may still occur on the front of the absorber tube wall. Therefore, during the normal operation of a solar thermal power station, it is sometimes inevitable to preheat in the scenario where the absorber is iced.
[0004] When the molten salt absorber is preheated, since only the front receives sunlight, the tube wall temperature on the front of the absorber rises much faster than that on the back. As a result, there is a huge temperature gradient in the circumferential direction of the tube wall of each absorber tube, which means that the tube wall thermal stress of each absorber tube is relatively large during the preheating process. If in this situation for a long time, the absorber tube may be bent or even ruptured, which will in turn affect the operation safety of the solar thermal power station. Therefore, the safety of the preheating process is very crucial for the solar thermal power station. In particular, when the front of the absorber is iced, the ice layer seriously affects the heat absorption and transfer of the absorber tube wall, thus having a great impact on both the thermal stress distribution and the preheating speed of the absorber preheating process. Therefore, clarifying the influence law of the icing condition on the absorber preheating process is of great significance for guiding and optimizing the preheating process of the molten salt absorber in a solar thermal power station.
[0005] However, there has been no report on a test system for the preheating performance of a molten salt absorber in a solar thermal power station after icing. Summary of the Invention
[0006] The object of the present invention is to provide a test system and method for the preheating performance of a molten salt absorber in a solar thermal power station after icing, which can measure the preheating performance of the molten salt absorber under different icing conditions, and provide data support and guidance for solving the preheating problem of the on-site molten salt absorber in the icing state.
[0007] To achieve the above object, according to the first aspect of the present invention, the following technical solutions are adopted: A test system for the preheating performance of a molten salt absorber in a solar thermal power station after icing, comprising a support frame, a molten salt absorber tube panel simulator, a thermocouple wire group, a data acquisition instrument, a simulated light heat source, a water storage tank and a heat flux measurement device; The top of the molten salt absorber tube panel simulator is connected to the support frame, and a simulated tube panel is arranged below the connection part of the molten salt absorber tube panel simulator and the support frame; a certain number of thermocouple wires are arranged on the outer wall of the simulated tube panel to form a thermocouple wire group; the thermocouple wire group is connected to the data acquisition instrument to record the temperature distribution and evolution during the preheating process; The simulated light heat source is responsible for generating a focused light spot and irradiating it onto the front of the simulated tube panel, and can match the front size of the simulated tube panel to be basically the same; The water storage tank is an open-top container in the shape of a flat box, with a height consistent with the length of the simulated tube panel, a width greater than the outer diameter of the heat absorption tube of the simulated tube panel, and a length matching the width of the simulated tube panel, and can be installed on the simulated tube panel from the lower part of the simulated tube panel; The heat flux measurement device is responsible for measuring the heat flux density distribution on the front of the simulated tube panel before the preheating experiment.
[0008] On the basis of adopting the above technical solutions, the present invention can also adopt the following further technical solutions, and use these further technical solutions in combination: The simulated light heat source adopts a xenon lamp group arranged in a matrix.
[0009] The simulated tube panel is composed of a number of identical thin-walled circular tubes arranged in sequence. The thin-walled circular tubes adopt the heat absorption tubes used in the molten salt absorber of the solar thermal power station. The upper end of the simulated tube panel is connected to the upper fixing structure, and the support frame is connected to the upper fixing structure.
[0010] The thermocouple wire group includes a number of thermocouple wires, and each thermocouple wire is welded to different places on the outer wall of the heat absorption tube of the simulated tube panel by spot welding.
[0011] The water storage tank is configured with a plurality of different widths to form ice layers of different thicknesses.
[0012] The material or inner surface of the water storage tank has hydrophobicity so that the water storage tank can be conveniently removed after the water in the tank freezes.
[0013] The orientation and power of each xenon lamp in the xenon lamp group are independently adjustable.
[0014] The present invention also provides a method for testing the preheating performance of a molten salt absorber in a solar thermal power plant after ice formation, based on the above-mentioned testing system for the preheating performance of a molten salt absorber in a solar thermal power plant after ice formation, comprising the following steps: Turn on the simulated light heat source with an adjusted angle in advance to cover the simulated tube bank, use a heat flux measuring device to measure the heat flux density distribution on the front of the simulated tube bank, obtain the required simulated lighting conditions, and then turn off the simulated light heat source and the heat flux measuring device; Install the water storage tank on the simulated tube bank so that the bottom and the back side of the water storage tank are closely attached to the bottom and the back side of the simulated tube bank, and then fill the water storage tank with water; Cool the water in the water storage tank into ice blocks by means of liquid nitrogen spraying or natural cooling; then remove the water storage tank; Turn on the simulated light heat source according to the adjusted parameters, and turn on the data acquisition instrument. Among them, each thermocouple wire on the heat absorption tube wall of the simulated tube bank has been connected to the data acquisition instrument, preheat the simulated tube bank and record the temperature data of each measuring point on the simulated tube bank; Judge whether the preheating is completed according to the temperature conditions obtained by the data acquisition instrument. After completion, first turn off the simulated light heat source. Wait until the temperatures at various places on the simulated tube bank drop to near the ambient temperature, and then turn off the data acquisition instrument. The preheating process test is over.
[0015] The beneficial effects of the present invention are as follows: Aiming at the problem that the ice formation on the molten salt absorber in a tower-type solar thermal power plant has a great influence on its preheating performance and the influence law has not been revealed, the present invention provides a testing system and method for the preheating performance of a molten salt absorber in a solar thermal power plant after ice formation, which can measure the preheating performance of the molten salt absorber under different ice formation conditions, and can provide data support and guidance for solving the preheating problem of the molten salt absorber in the field under the ice formation state. The thermocouple wire group in the provided testing system is arranged at various circumferential and axial positions of the absorber tube wall, detects and records the temperature changes at various positions on the tube wall, and can comprehensively and effectively reflect the overall preheating effect of the tube bank. The xenon lamp group in the provided testing system can better restore the scene of the half-week heating of the absorber on site, make the scene where the absorber is located closer to the actual situation on site, and ensure the effectiveness of the testing system. Description of the Drawings
[0016] Figure 1 It is a schematic structural diagram of a testing system for the preheating performance of a molten salt absorber in a solar thermal power plant after ice formation according to the present invention. Among them, for the sake of simplicity of the overall schematic diagram, only a part of the thermocouple wire group in the testing system is drawn; Figure 2 is Figure 1 In the testing system shown, a schematic diagram of the arrangement of the thermocouple wire group on the heat absorption tube; Figure 3 A schematic diagram of the scene of ice blocks formed on the front of the simulated tube bank shown.
[0017] Figure 4 For Figure 1 The schematic diagram of the water storage tank structure in the shown test system; Figure 5 For Figure 1 The schematic diagram after the installation of the simulated tube bank and the water storage tank in the shown test system; Figure 6 It is the schematic diagram of heat flux measurement in the test system. Specific implementation manner
[0018] The following further describes a test system and method for the preheating performance after the molten salt absorber of a solar thermal power station freezes, in conjunction with the accompanying drawings and specific implementation manners: As shown in the figure, a test system for the preheating performance after the molten salt absorber of a solar thermal power station freezes provided by the present invention includes a support frame 1, a molten salt absorber tube bank simulator 2, a thermocouple wire group 3, a data acquisition instrument 4, a water storage tank 6, a xenon lamp group 5, and a heat flux measurement device 7.
[0019] The bottom of the support frame 1 is fixed to the ground, and the top is fixedly connected or welded to the upper fixing structure 21 of the molten salt absorber tube bank simulator 2 by bolts, thereby fixing the molten salt absorber tube bank simulator 2 at a preset height position. The upper fixing structure 21 can adopt structures such as plates and seats suitable for connecting to a row of heat exchange tubes The molten salt absorber tube bank simulator 2 includes an upper fixing structure 21 and a simulated tube bank 22 formed by arranging a number of identical thin-walled circular tubes in sequence. The thin-walled circular tubes adopt the absorber tubes used in the molten salt absorber of a solar thermal power station, and the upper end of the simulated tube bank 22 is welded to the upper fixing structure 21. The molten salt absorber tube bank simulator 2 only has a fixing structure 21 at the top and no fixing structure at the bottom, so as to facilitate the installation of the water storage tank 6 from the bottom.
[0020] As Figure 2 shown, a number of thermocouple wires are arranged circumferentially and axially on the outer wall of the absorber tubes of the simulated tube bank 22 to form a thermocouple wire group 3. Figure 2 The black dots on the simulated tube bank 22 in the figure are the measuring points of the thermocouple wires, and the circumferential and axial measuring points are arranged at equal angular intervals and equal distance intervals respectively. The number of thermocouple wires arranged depends on the actual needs. If it is necessary to measure the temperature data at more positions, they are arranged more densely circumferentially and axially, and vice versa, they can be arranged more sparsely. Each thermocouple wire is independently welded to a specified position on the wall of the absorber tube of the simulated tube bank 22 by a spot welder. Among them, no thermocouple wire is welded to the back vertex of the absorber tube, and for the measuring points located in the latter half of the absorber tube, the thermocouple wires pass through the gaps between the absorber tubes.
[0021] The other ends of the thermocouple wires are connected to the data acquisition instrument 4. The data acquisition instrument 4 can not only record and save the temperature data measured by each thermocouple wire during the preheating process according to the set sampling frequency, but also display and monitor the temperature situation by connecting to a computer, so that it can judge whether to end the preheating process by observing the highest wall temperature of the simulated tube screen 22 measured in real time on the computer.
[0022] Figure 3 The scene of ice cubes 8 forming on the front of the simulated tube screen 22 is shown.
[0023] As Figure 4 shown, the water storage tank 6 is an open-top container in the shape of a flat box, whose length and height are respectively the same as the width and length of the simulated tube screen 22. The width of the water storage tank 6 is greater than the outer diameter of the heat absorption tubes of the simulated tube screen 22, and the specific width size is adjusted according to the required ice layer thickness, which can be achieved by replacing the water storage tank 6 with different widths, so as to form ice layers with different required thicknesses.
[0024] The water storage tank 6 is installed on the molten salt heat absorber tube screen simulator 2 from the bottom of the simulated tube screen 22. As Figure 5 shown, finally the bottom and back side of the water storage tank 6 are closely attached to the bottom and back side of the simulated tube screen 22, and then the water storage tank 6 is filled with water from the top. One of the characteristics of ice formation on the molten salt heat absorber of a solar thermal power station is that the ice layer is not thick. The water in the water storage tank 6 can be cooled and frozen by spraying liquid nitrogen from the front side of the water storage tank 6, or the water in the water storage tank 6 can be naturally frozen by using the relatively low ambient temperature in winter. The material or inner surface of the water storage tank 6 has hydrophobicity, so that after the water in the tank freezes, the water storage tank 6 can be conveniently removed. After the ice layer is formed, the front side and bottom of the water storage tank 6 can also be slightly heated by a heater, so that the water storage tank 6 can be conveniently removed.
[0025] The xenon lamp group 5 is formed by arranging and stacking a number of xenon lamps. The xenon lamp group 5 is responsible for generating a focused light spot on the front of the simulated tube screen 22. The number of xenon lamps is selected according to the light-receiving area on the front of the simulated tube screen 22 and the heat flux density of the light spot, etc. Each xenon lamp is installed on a xenon lamp holder and can be rotated in the horizontal and vertical directions to adjust the irradiation angle, and the power of each xenon lamp is independently adjustable, so as to adjust the size and position of the focused light spot to be basically the same as the light-receiving part on the front of the simulated tube screen 22. The reason for choosing xenon lamps as the light source is mainly that the spectral characteristics of xenon lamps are very close to those of sunlight, and it is an adjustable simulated light heat source.
[0026] As Figure 6 shown, the heat flux measurement device 7 is responsible for measuring the heat flux density distribution of the focused light spot on the front of the simulated tube screen 22 before each preheating experiment. In order to ensure that the heat flux density distribution of the focused light spot meets the requirements, the power of each xenon lamp can be precisely adjusted, and finally the required heat flux density distribution can be obtained.
[0027] According to the above test system, the test method for the preheating performance of the molten salt absorber in a solar thermal power plant after ice formation is as follows: Turn on the xenon lamp group 5 that has been pre - debugged, use the heat flux measuring device 7 to measure the heat flux density distribution on the front of the simulated tube bank 22, obtain the required simulated illumination conditions, and then turn off the xenon lamp group 5 and the heat flux measuring device 7; Install the water storage tank 6 on the simulated tube bank 22, and then fill the water storage tank 6 with water; Cool the water in the water storage tank 6 into ice cubes by means of liquid nitrogen spraying or natural cooling; Slightly heat the front side and bottom of the water storage tank 6 with a heater, and remove the water storage tank 6; Turn on the xenon lamp group 5 according to the adjusted parameters and postures, and turn on the data acquisition instrument 4. Among them, each thermocouple wire on the heat absorption tube wall of the simulated tube bank 22 has been connected to the data acquisition instrument 4. Preheat the simulated tube bank 22 and record the temperature data of each measuring point on the simulated tube bank 22; Judge whether the preheating is completed according to the temperature situation obtained by the data acquisition instrument 4. After completion, first turn off the xenon lamp group 5. Wait until the temperatures at various places on the simulated tube bank 22 drop to near the ambient temperature, and then turn off the data acquisition instrument 4. The test of the preheating process ends.
[0028] The present invention can test the influence of heat flux density and ice layer thickness on the preheating performance of the molten salt absorber after ice formation. Among them, by changing the width of the water storage tank 6, the ice layer thickness can be changed, so as to simulate the ice - formation conditions under different ambient temperatures in winter. By changing the heating power, the preheating conditions under different concentrated radiation intensities can be simulated. The above conditions can be realized by adjusting the power of the xenon lamp group 5 and setting water storage tanks 6 with different widths respectively.
[0029] Using the test system of the present invention, the influence of heat flux density on the preheating performance of the molten salt absorber after ice formation can be tested. The following method is recommended for this experiment. Keep the ice layer thickness unchanged, and then conduct at least 4 groups of tests under different powers of the xenon lamp group 5. The tests can measure the preheating speed, the temperature distribution and evolution of the tube wall during the preheating process under the ice - formation conditions of the absorber at different heat flux densities. Through data processing, the influence laws of heat flux density on the preheating time and the tube wall thermal stress under the ice - formation conditions of the absorber can be obtained.
[0030] Using the test system of the present invention, the influence of ice layer thickness on the preheating performance of the molten salt absorber after ice formation can be tested. The following method is recommended for this experiment. Keep the power of the xenon lamp group 5 unchanged, and then conduct at least 4 groups of tests under different ice layer thicknesses. The tests can measure the preheating speed, the temperature distribution and evolution of the tube wall during the preheating process under the ice - formation conditions of the absorber at different ice layer thicknesses. Through data processing, the influence laws of ice layer thickness on the preheating time and the tube wall thermal stress under the ice - formation conditions of the absorber can be obtained.
[0031] During the preheating of the molten salt absorber in an actual solar thermal power station, it is necessary to ensure both a relatively fast preheating speed and that the pipe wall stress during preheating does not become too large (since the preheating process is carried out daily, the pipeline is prone to fatigue damage or even rupture under long-term large thermal stress). Therefore, the laws obtained by this test system can be applied to guide the preheating process of the molten salt absorber in an actual solar thermal power station under icing conditions. For example, by measuring the ice layer thickness on-site of the molten salt absorber in the solar thermal power station, a reasonable heliostat field scheduling plan (to obtain an appropriate heat flux density) can be designed for preheating.
[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A test system for the preheating performance of a molten salt heat absorber in a solar thermal power station after icing, characterized in that, The described test system includes a support frame (1), a molten salt absorber tube panel simulator (2), a thermocouple wire group (3), a data acquisition instrument (4), a simulated light heat source, a water storage tank (6), and a heat flux measurement device (7); The top of the molten salt absorber tube panel simulator (2) is connected to the support frame (1), and a simulated tube panel (22) is provided below the connection part of the molten salt absorber tube panel simulator (2) and the support frame (1); a certain number of thermocouple wires are arranged on the outer wall of the simulated tube panel (22) to form a thermocouple wire group (3); the thermocouple wire group (3) is connected to the data acquisition instrument (4), so as to record the temperature distribution and evolution during the preheating process; The simulated light heat source is responsible for generating a focused light spot and irradiating it onto the front of the simulated tube panel (22), and can match the front size of the simulated tube panel (22) to be basically the same; The water storage tank (6) is an open-top container in the shape of a flat box, with its height being the same as the length of the simulated tube panel (22), its width being greater than the outer diameter of the heat absorption tube of the simulated tube panel (22), and its length matching the width of the simulated tube panel (22), and it can be installed on the simulated tube panel (22) from the lower part of the simulated tube panel (22); The heat flux measurement device (7) is responsible for measuring the heat flux density distribution on the front of the simulated tube panel (22) before the preheating experiment.
2. The test system for the preheating performance of a molten salt heat absorber in a solar thermal power station after icing, as described in claim 1, is characterized in that, The described simulated light heat source adopts a xenon lamp group (5) arranged in a matrix.
3. The test system for the preheating performance after freezing of the molten salt heat absorber of the solar thermal power station according to claim 1, wherein, The simulated tube panel (22) is formed by arranging a number of identical thin-walled circular tubes in sequence. The thin-walled circular tubes are the heat absorption tubes used in the molten salt absorber of a solar thermal power plant. The upper end of the simulated tube panel (22) is connected to the upper fixing structure (21), and the support frame (1) is connected to the upper fixing structure (21).
4. The test system for the preheating performance after ice formation of the molten salt heat absorber in a solar thermal power station according to claim 1, characterized in that, The thermocouple wire group (3) includes a number of thermocouple wires, and each thermocouple wire is welded to different positions on the outer wall of the heat absorption tube of the simulated tube panel (22) by spot welding.
5. The test system for the preheating performance of the molten salt heat absorber in a solar thermal power station after icing, as claimed in claim 1, is characterized in that A plurality of water storage tanks (6) with different widths are configured to form ice layers with different thicknesses.
6. The test system for the preheating performance of the molten salt heat absorber in a solar thermal power station after icing, as described in claim 1, is characterized in that The material or inner surface of the water storage tank (6) has hydrophobicity, so that the water storage tank (6) can be conveniently removed after the water in the tank freezes.
7. The test system for the preheating performance of the molten salt heat absorber in a solar thermal power station after icing, as claimed in claim 2, is characterized in that, The orientation and power of each xenon lamp in the xenon lamp group (5) are independently adjustable.
8. A method for testing the preheating performance of a molten salt absorber in a solar thermal power plant after icing, based on the testing system for the preheating performance of the molten salt absorber in the solar thermal power plant according to claim 1, characterized in that It includes the following steps: Turn on the simulated light heat source with the angle pre-adjusted to cover the simulated tube panel (22), use the heat flux measurement device (7) to measure the heat flux density distribution on the front of the simulated tube panel (22) to obtain the required simulated light illumination conditions, and then turn off the simulated light heat source and the heat flux measurement device; Install the water storage tank (6) on the simulated tube panel (22) so that the bottom and back side of the water storage tank (6) are closely attached to the bottom and back side of the simulated tube panel (22), and then fill the water storage tank (6) with water; Cool the water in the water storage tank (6) into ice cubes by means of liquid nitrogen spraying or natural cooling; then remove the water storage tank (6); Turn on the simulated light heat source according to the adjusted parameters, turn on the data acquisition instrument (4). Among them, each thermocouple wire on the heat absorption tube wall of the simulated tube panel (22) has been connected to the data acquisition instrument (4), preheat the simulated tube panel (22) and record the temperature data of each measurement point on the simulated tube panel; Judge whether the preheating is completed according to the temperature obtained by the data acquisition instrument (4). After completion, first turn off the simulation light heat source. Wait until the temperatures at various parts of the simulated tube screen (22) drop to near the ambient temperature, then turn off the data acquisition instrument (4), and the preheating process test ends.