Tower type solar heat absorption system and anti-freezing and anti-blocking method for heat absorber

Abstract

The invention discloses a tower type solar heat absorption system and an anti-freezing and anti-blocking method for a heat absorber. The heat absorber is arranged on a heat absorption tower; the heat storage medium conveying unit is configured to be capable of inputting the low-temperature heat storage medium into the heat absorber and outputting the high-temperature heat storage medium subjected to heat absorption by the heat absorber; the pre-storage unit is arranged on the heat absorption tower, the pre-storage unit comprises a medium storage module, a heating module and a circulation module, and a pre-storage heat medium is arranged in the medium storage module; the circulating module is configured to enable the pre-stored heat medium to circularly flow between the medium storage module and the heat absorber; the heating module is arranged in the medium storage module and / or on the medium circulation module, and the heating module is used for heating the pre-stored heat medium. Based on the principle that a high-temperature heat storage medium builds self-circulation in the heat absorber before sunrise, salt dissolving operation can be conducted on a frozen and blocked heat absorber pipeline in advance, and pipe blocking of the heat absorber is effectively prevented.

Description

Technical Field

[0001] The present invention belongs to the technical field of tower-type solar thermal power plants, and particularly relates to a tower-type solar energy heat absorption system and a method for preventing and removing freezing and blockage of a heat absorber. Background Art

[0002] In the field of tower-type solar thermal power plants, the heat absorption tube, as a key component of the heat collection system, undertakes the important task of converting sunlight into heat energy and storing and transmitting it through heat transfer media such as media. However, during the design and operation of the heat absorption tubes in current tower-type solar thermal power plants, there is an urgent problem to be solved - the lack of effective anti-freezing and anti-blocking measures. Under cold or extreme weather conditions, the medium in the heat absorption tube is prone to freezing or blocking due to temperature reduction, seriously affecting the normal operation and power generation efficiency of the solar thermal power plant.

[0003] In the prior art, once the heat absorption tube is frozen and blocked, the usually adopted measure is to directly irradiate the blocked part with sunlight during the day, and rely on the heat of solar energy to gradually melt the medium at the blocked position. However, this solution has many deficiencies. Most of the heliostats cannot participate in heat collection during the salt melting period, thus significantly reducing the heat collection amount and power generation amount of the project, and affecting the overall economic benefits of the solar thermal power plant. Secondly, the height of the heat absorption tower of the tower-type solar thermal power plant is about two hundred meters, which requires the medium pump to have a relatively high head and power. Therefore, the self-circulation scheme of the medium pump adopted for salt melting is not cost-effective economically, consumes a large amount of plant electricity, and increases the operating cost of the solar thermal power plant. Summary of the Invention

[0004] To solve the above problems, the purpose of the present invention is to provide a tower-type solar energy heat absorption system and a method for preventing and removing freezing and blockage of a heat absorber. The system achieves the effect of preventing blockage of the heat absorber in advance by establishing a self-circulation principle of a high-temperature heat storage medium in the heat absorber before sunrise.

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

[0006] A tower-type solar energy heat absorption system, comprising:

[0007] A heat absorber, which is installed on the heat absorption tower;

[0008] A heat storage medium conveying unit, which is configured to be able to input a low-temperature heat storage medium into the heat absorber and output the high-temperature heat storage medium that has absorbed heat through the heat absorber;

[0009] A pre-storage unit, which is installed on the heat absorption tower. The pre-storage unit includes a medium storage module, a heating module, and a circulation module, and a pre-stored heat storage medium is provided in the medium storage module;

[0010] The circulation module is configured to enable the pre-stored heat medium to circulate between the medium storage module and the heat absorber;

[0011] The heating module is disposed in the medium storage module, and / or the heating module is disposed on the medium circulation module, and the heating module is used to heat the pre-stored heat medium.

[0012] According to an embodiment of the present invention, the medium circulation module includes a circulation pipeline and a medium driving component, and the medium driving component is disposed on the circulation pipeline for outputting the pre-stored heat medium in the medium storage module from the medium storage module.

[0013] According to an embodiment of the present invention, the circulation pipeline includes a medium input pipeline and a medium output pipeline;

[0014] The first end of the medium input pipeline is connected to the medium input end of the medium storage module, and the second end of the medium input pipeline is connected to the medium output end of the heat absorber;

[0015] The first end of the medium output pipeline is connected to the medium output end of the medium storage module, and the second end of the medium output pipeline is connected to the medium input end of the heat absorber;

[0016] Wherein, a first valve assembly is arranged between the first end and the second end of the medium output pipeline, and a second valve assembly is arranged between the first end and the second end of the medium input pipeline.

[0017] According to an embodiment of the present invention, the heating module is an electric heater;

[0018] The electric heater is arranged on the medium output pipeline, or the electric heater is arranged on the medium input pipeline;

[0019] The medium driving component is a medium pump, the medium pump is disposed in the medium storage module, and the medium pump is communicated with the medium output end of the medium storage module.

[0020] According to an embodiment of the present invention, a conversion layer platform is provided at the upper end of the heat absorption tower, and the pre-storage unit is disposed on the conversion layer platform.

[0021] According to an embodiment of the present invention, the heat storage medium conveying unit includes a rising pipeline and a descending pipeline;

[0022] The rising pipeline is connected to the medium input end of the heat absorber, and the rising pipeline is used to input low-temperature molten salt into the heat absorber;

[0023] The descending pipeline is connected to the medium output end of the heat absorber, and the descending pipeline is used to output the high-temperature molten salt after being heated by the heat absorber;

[0024] Wherein, the heat storage medium is molten salt, the medium storage module is a high-temperature molten salt storage tank, and the pre-stored heat storage medium is high-temperature molten salt.

[0025] According to an embodiment of the present invention, the heat storage medium conveying unit further includes an inlet buffer tank and an outlet buffer tank;

[0026] The ascending pipeline communicates with the input end of the inlet buffer tank, and the output end of the inlet buffer tank is connected to the medium input end of the heat absorber through a first pipeline;

[0027] The descending pipeline communicates with the output end of the outlet buffer tank, and the input end of the outlet buffer tank is connected to the medium output end of the heat absorber through a second pipeline;

[0028] Wherein, the second end of the medium output pipeline is connected to the first pipeline, and the second end of the medium input pipeline is connected to the second pipeline; the heating module is arranged on the medium input pipeline.

[0029] According to an embodiment of the present invention, a third valve assembly is arranged on the ascending pipeline, and a fourth valve assembly is arranged on the descending pipeline;

[0030] A fifth valve assembly is arranged on the first pipeline, and the fifth valve assembly is arranged between the second end of the medium output pipeline and the medium input end of the heat absorber.

[0031] According to an embodiment of the present invention, it further includes a control unit and a plurality of thermocouples. The plurality of thermocouples are arranged at various positions of the heat absorber, and the control unit is configured to control the tower-type solar heat absorber system through the temperature information of the plurality of thermocouples.

[0032] According to an embodiment of the present invention, adopting the tower-type solar heat absorber system as described in claim 8, the medium storage module is a high-temperature medium storage tank, and the pre-stored heat storage medium is a high-temperature heat storage medium, including the following steps:

[0033] S1: At a predetermined time, close the heat storage medium conveying unit and stop conveying the low-temperature heat storage medium into the heat absorber;

[0034] S2: Open the medium circulation module in the pre-storage unit, so that the pre-stored heat storage medium enters the heat absorber and forms a circulation between the medium storage module and the heat absorber;

[0035] S3: After the pre-stored heat medium circulates in the heat absorber for a predetermined time, it is determined whether there is pipe blockage inside the heat absorber by the temperatures of the thermocouples at various positions inside the heat absorber;

[0036] S4: If it is determined that there is pipe blockage, the heating module is turned on to heat the pre-stored heat medium until the salt melting at the blocked part is completed;

[0037] If it is determined that there is no pipe blockage, the heating module is turned on after the temperature of the pre-stored heat medium is lower than the preset temperature;

[0038] S5: After sunrise and after the heat absorber receives the concentrated light from the heliostat field, the heat storage medium conveying unit is opened and the pre-storage unit is closed.

[0039] Due to the adoption of the above technical solutions, the present invention has the following advantages and positive effects compared with the prior art:

[0040] Based on the unique principle that the high-temperature heat storage medium in the tower-type solar heat absorber establishes a self-circulation inside the heat absorber before sunrise, the tower-type solar heat absorption system in the present invention can perform salt melting operation on the frozen and blocked heat absorber pipeline in advance, effectively preventing the occurrence of heat absorber pipe blockage. That is, the pre-stored heat medium in the heat absorber can achieve self-circulation before sunrise, ensuring that the heat absorber can still maintain a good working state in a low-temperature environment, and avoiding equipment damage and production interruption caused by freezing and blockage. At the same time, the present invention can directly provide the heat absorber with a pre-stored heat medium at 565 °C. This high-temperature heat storage medium can significantly improve the salt melting efficiency at the blocked part, quickly dredge the blocked pipeline, reduce the production stagnation time caused by pipe blockage, and improve the stability and reliability of the entire heat absorption system.

[0041] After sunrise, the present invention can directly let all the heliostats project onto the heat absorber without the links of preheating and salt melting of the heat absorber. This improvement avoids the time consumed in the preheating and salt melting processes in the traditional process, enables the heat absorber to enter the normal working state faster, thereby increasing the effective absorption time of the heat absorber for solar energy, significantly improving the utilization efficiency of solar energy resources, and contributing to improving the overall power generation and economic benefits of the heat absorption system.

[0042] By arranging the pre-storage unit on the conversion layer platform of the tower body, the tower-type solar heat absorption system in the present invention is only 20-30 meters away from the heat absorber. Compared with the traditional medium conveying pipeline arranged in a heat absorption tower more than 200 meters high, the distance is reduced by an order of magnitude. This close arrangement method greatly shortens the pipeline length of the medium circulation, reduces the resistance loss in the medium conveying process, and thus can significantly reduce the consumption of factory electricity in the pipe blockage and salt melting stage of the heat absorber, reducing the operation cost of the heat absorption system.

[0043] The tower solar energy absorption system in the present invention does not need to change the existing process system and its pipeline materials, and has good compatibility and universality. This means that when upgrading technology using the technical solution of the present invention, there is no need to carry out large-scale transformation and replacement of existing equipment, reducing the difficulty and cost of technology implementation. At the same time, it also reduces the risk of production interruption that may be brought about by equipment transformation, which is conducive to the rapid popularization and application of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The following further elaborates on the specific implementation manners of the present invention in conjunction with the drawings, where:

[0045] Figure 1 is a schematic diagram of the whole of the present invention.

[0046] Description of the reference numerals in the drawings:

[0047] 1, rising pipeline; 2, third valve assembly; 3, inlet buffer tank; 4, heat absorber; 5, falling pipeline; 6, outlet buffer tank; 7, fourth valve assembly; 8, medium output pipeline; 9, electric heater; 10, second valve assembly; 11, medium storage module; 12, medium pump; 13, medium input pipeline; 14, first valve assembly; 15, conversion layer platform; 16, fifth valve assembly; 17, first pipeline; 18, second pipeline. SPECIFIC IMPLEMENTATION MANNERS

[0048] The following further elaborates on the present invention in conjunction with the drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, only for conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention.

[0049] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If this specific posture changes, then the directional indications will also change accordingly.

[0050] Embodiment 1

[0051] Refer to Figure 1 , the core of the present invention is to provide a tower solar energy absorption system applicable to tower-type solar thermal power plants in high-wind speed and low-temperature regions. Because in high-wind speed and low-temperature regions, the heat absorber pipelines are prone to freezing and blocking, and a solution for preventing freezing and blocking of the heat absorber pipelines needs to be provided.

[0052] The tower-type solar heat absorption system of the present invention includes a heat absorber 4, a heat storage medium conveying unit, and a pre-storage unit. The heat absorber 4 is installed on the heat absorption tower; the heat storage medium conveying unit is configured to be able to input the low-temperature heat storage medium into the heat absorber 4 and output the high-temperature heat storage medium after being heated by the heat absorber 4; the pre-storage unit is installed on the heat absorption tower, and the pre-storage unit includes a medium storage module 11, a heating module, and a circulation module. The medium storage module 11 stores pre-stored heat storage medium; the circulation module is configured to be able to circulate the pre-stored heat storage medium between the medium storage module 11 and the heat absorber 4; the heating module is arranged in the medium storage module 11, and / or the heating module is arranged on the medium circulation module, and the heating module is used to heat the pre-stored heat storage medium.

[0053] Specifically, as shown in the attached Figure 1 In general, the heat absorber 4 is arranged on the top of the heat absorption tower. There is also a conversion layer platform 15 arranged in the upper part of the heat absorption tower (generally at a position close to the top of the heat absorption tower). The pre-storage unit is arranged on the conversion layer platform 15. Furthermore, the medium storage module 11 is also arranged on the conversion layer platform 15. The pre-stored heat storage medium in the medium storage module 11 can be flexibly called; when an emergency is about to occur or has already occurred, the pre-stored heat storage medium in the medium storage module 11 (that is, the pre-stored heat storage medium in the medium storage module 11) can be called, and a circulation between the medium storage module 11 and the heat absorber 4 is established on the heat absorption tower through the circulation module to cope with the emergency situation. In the embodiment of the present technical solution, the emergency situation to be coped with usually refers to the situation of heat storage medium pipe blockage, and the pre-stored heat storage medium in the medium storage module 11 is high-temperature heat storage medium; when the situation of heat storage medium pipe blockage occurs, the high-temperature heat storage medium in the medium storage module 11 is introduced into the heat absorber 4, and a circulation between the medium storage module 11 and the heat absorber 4 is established to gradually melt the heat storage medium at the pipe blockage position. Of course, in other embodiments of the present technical solution, the emergency situation to be coped with may be that the heat storage medium conveying unit is damaged and cannot convey the low-temperature heat storage medium into the heat absorber 4. The working heat absorber 4 may be damaged if it is not introduced with low-temperature heat storage medium for a long time; at this time, the medium storage module 11 stores low-temperature heat storage medium, so that the low-temperature heat storage medium in the medium storage module 11 is introduced into the heat absorber 4 through the circulation module to ensure the normal operation of the heat absorber 4. How to specifically use the pre-storage unit can be designed according to the actual situation.

[0054] It should be particularly noted that the heat storage medium in the present technical solution will melt into a molten body after being heated and will solidify after the temperature is lower than the freezing point; preferably, the heat storage medium is molten salt (molten state of inorganic salts, such as molten state of a mixture of sodium nitrate and potassium nitrate). The high-temperature heat storage medium in the medium storage module 11 can be a part of the high-temperature heat storage medium reserved after being heated by the heat absorber 4, or the high-temperature heat storage medium heated by the heating module.

[0055] In an embodiment of the present technical solution, the medium circulation module includes a circulation pipeline and a medium driving component. The medium driving component is arranged on the circulation pipeline and is used to output the pre-stored hot medium in the medium storage module 11 from the medium storage module 11.

[0056] Specifically, referring to the appendix Figure 1 As shown, the circulation pipeline includes a medium input pipeline 13 and a medium output pipeline 8; the first end of the medium input pipeline 13 is connected to the medium input end of the medium storage module 11, and the second end of the medium input pipeline 13 is connected to the medium output end of the heat absorber 4; the first end of the medium output pipeline 8 is connected to the medium output end of the medium storage module 11, and the second end of the medium output pipeline 8 is connected to the medium input end of the heat absorber 4; wherein, a first valve assembly 14 is arranged between the first end and the second end of the medium output pipeline 8, and a second valve assembly 10 is arranged between the first end and the second end of the medium input pipeline 13. The first valve assembly 14 is one of valves such as a globe valve, a gate valve, a solenoid valve, a ball valve, etc.; the second valve assembly 10 is one of valves such as a globe valve, a gate valve, a solenoid valve, a ball valve, etc.

[0057] Furthermore, the heating module is an electric heater 9; the electric heater 9 is arranged on the medium output pipeline 8, or the electric heater 9 is arranged on the medium input pipeline 13; the medium driving component is a medium pump 12, the medium pump 12 is arranged in the medium storage module 11, and the medium pump 12 is communicated with the medium output end of the medium storage module 11.

[0058] It should be particularly noted that generally, the heating module is an electric heater 9. Of course, in other embodiments, it can also be of other types, such as a thermocouple, etc., which is not limited in this embodiment. The electric heater 9 can be installed on the medium input pipeline 13 to heat the pre-stored hot medium input into the medium storage module 11; the electric heater 9 can also be installed on the medium output pipeline 8 to heat the pre-stored hot medium output from the medium storage module 11. Preferably, the electric heater 9 can be installed on the medium input pipeline 13 to heat the pre-stored hot medium input into the medium storage module 11.

[0059] In an embodiment of the present technical solution, the heat storage medium conveying unit includes a rising pipeline 1 and a falling pipeline 5; the heat storage medium is molten salt, the medium storage module 11 is a high-temperature molten salt storage tank, and the pre-stored hot medium is high-temperature molten salt; the rising pipeline 1 is connected to the medium input end of the heat absorber 4, and the rising pipeline 1 is used to input low-temperature molten salt into the heat absorber 4; the falling pipeline 5 is connected to the medium output end of the heat absorber 4, and the falling pipeline 5 is used to output the high-temperature molten salt after being heated by the heat absorber 4.

[0060] Specifically, referring to the appendix Figure 1As shown, generally, one end of the rising pipeline 1 is connected to the medium input end of the heat absorber 4, and the other end is connected to a low-temperature medium storage tank (such as a cold salt tank) located outside the heat absorption tower. Thus, the low-temperature heat storage medium (such as low-temperature molten salt) in the low-temperature medium storage tank is input into the heat absorber 4 through the rising pipeline 1. The low-temperature heat storage medium flows in the heat absorber 4 and absorbs heat energy, thereby heating the low-temperature heat storage medium (such as low-temperature molten salt) into a high-temperature heat storage medium (such as high-temperature molten salt); one end of the descending pipeline 5 is connected to the medium output end of the heat absorber 4, and the other end is connected to a high-temperature medium storage tank (such as a hot salt tank) located outside the heat absorption tower. Thus, the high-temperature heat storage medium (such as high-temperature molten salt) after absorbing heat in the heat absorber 4 is input into the high-temperature medium storage tank (such as a hot salt tank) for storage.

[0061] In the embodiment of this technical solution, the heat storage medium conveying unit further includes an inlet buffer tank 3 and an outlet buffer tank 6; the rising pipeline 1 communicates with the input end of the inlet buffer tank 3, and the output end of the inlet buffer tank 3 is connected to the medium input end of the heat absorber 4 through a first pipeline 17; the descending pipeline 5 communicates with the output end of the outlet buffer tank 6, and the input end of the outlet buffer tank 6 is connected to the medium output end of the heat absorber 4 through a second pipeline 18; wherein, the second end of the medium output pipeline 8 is connected to the first pipeline 17, and the second end of the medium input pipeline 13 is connected to the second pipeline 18; the heating module is installed on the medium input pipeline 13.

[0062] Furthermore, a third valve assembly 2 is provided on the rising pipeline 1, and a fourth valve assembly 7 is provided on the descending pipeline 5; a fifth valve assembly 16 is provided on the first pipeline 17, and the fifth valve assembly 16 is arranged between the second end of the medium output pipeline 8 and the medium input end of the heat absorber 4. The third valve assembly 2 is one of valves such as a globe valve, a gate valve, a solenoid valve, a ball valve, etc.; the fourth valve assembly 7 is one of valves such as a globe valve, a gate valve, a solenoid valve, a ball valve, etc.; the fifth valve assembly 16 is one of valves such as a globe valve, a gate valve, a solenoid valve, a ball valve, etc.

[0063] It should be noted specifically that, as shown in the appendix Figure 1 As shown, most of the currently used heat absorbers 4 are composed of multiple tube screens connected to each other; each tube screen is respectively connected to the descending pipeline 5 or the outlet buffer tank 6 (as shown in the part of the heat absorber 4 in the appendix Figure 1 ), and is used to discharge the heat storage medium in the tube screen of the heat absorber 4 in case of emergency.

[0064] In the embodiment of this technical solution, it further includes a control unit and a number of thermocouples. The number of the thermocouples is installed at various positions of the heat absorber 4 (that is, on the heat absorption tubes in the tube screen of the heat absorber 4). The control unit is configured to control the tower-type solar heat absorption system through the temperature information of the number of the thermocouples. The specific control method will be described in detail in the subsequent embodiments.

[0065] Example 2

[0066] Refer to Figure 1 , another core of the present invention is to provide an anti-freezing and anti-blocking method for a tower-type solar heat absorption system. Using the tower-type solar heat absorption system in Example 1, the medium storage module 11 is a high-temperature medium storage tank, and the pre-stored heat medium is a high-temperature heat storage medium, including the following steps:

[0067] S1: At a predetermined time (i.e., the time set according to weather conditions, or the start time set after judging the blockage of the heat absorber 4, etc.), close the heat storage medium delivery unit and stop delivering the low-temperature heat storage medium to the heat absorber 4;

[0068] S2: Open the medium circulation module in the pre-storage unit to allow the pre-stored heat medium to enter the heat absorber 4 and form a circulation between the medium storage module 11 and the heat absorber 4;

[0069] S3: After the pre-stored heat medium circulates in the heat absorber 4 for a predetermined time, judge whether a blockage occurs inside according to the temperature of the thermocouples at various positions in the heat absorber 4;

[0070] S4: If it is judged that a blockage occurs, turn on the heating module to heat the pre-stored heat medium until the salt at the blockage point is melted;

[0071] If it is judged that no blockage occurs, turn on the heating module after the temperature of the pre-stored heat medium is lower than the preset temperature;

[0072] S5: After sunrise and after the heat absorber 4 receives the concentrated light from the heliostat field, open the heat storage medium delivery unit and close the pre-storage unit.

[0073] As an optional but non-limiting implementation manner, specifically, refer to the appendix Figure 1 As shown, the heat storage medium is molten salt, the medium storage module 11 is a high-temperature molten salt storage tank, and the pre-stored heat medium is high-temperature molten salt; during the salt combing the previous day, a part of the high-temperature pre-stored heat medium (i.e., high-temperature molten salt) is reserved in the high-temperature molten salt storage tank (i.e., the medium storage module 11), and the amount of this part of the pre-stored heat medium (i.e., high-temperature molten salt) is sufficient to circulate between the heat absorber 4 and the high-temperature molten salt storage tank.

[0074] Through the weather forecast and meteorological prediction system, when it is judged that the temperature will be relatively low and the wind speed will be relatively high tomorrow, the tower-type solar heat absorption system is started in advance. At this time, the anti-freezing and anti-blocking method of the tower-type solar heat absorption system includes the following steps:

[0075] S1: Calculate the sunrise time of the next day and close the third valve assembly 2 and the fourth valve assembly 7 at a predetermined time before sunrise. For example, if the sunrise time calculated on this day is 7:15, then close the third valve assembly 2 and the fourth valve assembly 7 at 5:15.

[0076] S2: Then open the first valve assembly 14, the second valve assembly 10 and the medium pump 12, so that the pre-stored heat medium (i.e., high-temperature molten salt) flows from the high-temperature molten salt storage tank into the heat absorber 4 and fills each tube bank of the heat absorber 4 to establish a self-circulation between the high-temperature molten salt storage tank and the heat absorber 4.

[0077] S3: After establishing the self-circulation between the high-temperature molten salt storage tank and the heat absorber 4 for a period of time, it can be judged whether a pipe blockage occurs by the temperature of the thermocouples of each tube bank of the heat absorber 4. For example, when the temperature at a certain tube bank position of the heat absorber 4 is significantly lower than the temperature nearby, a pipe blockage occurs.

[0078] S4: If it is judged that a pipe blockage occurs, turn on the electric heater 9 to heat the pre-stored heat medium (i.e., high-temperature molten salt), and maintain the temperature of the pre-stored heat medium (i.e., high-temperature molten salt) above 565 °C until the salt melting at the pipe blockage is completed. At this time, the entire heat absorption system needs to operate at this temperature. The pre-stored heat medium (i.e., high-temperature molten salt) will keep the heat absorber 4 at a relatively high temperature. At the same time, the solid medium at the pipe blockage will be heated by the pre-stored heat medium (i.e., high-temperature molten salt) at 565 °C, and the molten salt at the frozen blockage will gradually melt under the effects of heat conduction and heat radiation. When the temperature at the pipe blockage gradually becomes consistent with the temperature of the nearby tube bank of the heat absorber 4, it is considered that the salt melting is completed.

[0079] If the temperature distribution of each tube bank of the entire heat absorber 4 is uniform and there is no position significantly lower than the surrounding area, it is judged that no pipe blockage occurs. Then, when the temperature of the pre-stored heat medium (i.e., high-temperature molten salt) is lower than the preset temperature of 290 °C, turn on the electric heater 9. Therefore, the electric heater 9 only plays an anti-condensation role. When the pre-stored heat medium (i.e., high-temperature molten salt) does not need to be provided, the electric heater 9 is only turned on when the medium temperature is lower than 290 °C, and then stop the operation of the electric heater 9 until the heliostat field starts to concentrate sunlight after sunrise.

[0080] S5: After sunrise and when the heat absorber 4 receives the concentrated sunlight from the heliostat field and the pipe blockage salt melting is completed or there is no pipe blockage, open the third valve assembly 2. After the low-temperature molten salt enters the inlet buffer tank 3 and the liquid level of the outlet buffer tank 6 starts to rise, then open the fourth valve assembly 7. At this time, the heat absorber 4 is jointly composed of the tower-bottom heat absorption system (i.e., the system between the heat storage medium conveying unit and the heat absorber 4) and the tower-top pre-stored unit. Since it is already the normal operation time after sunrise when the mirror field is put into use, finally, it will be the shutdown process of the pre-stored unit. First, turn off the medium pump 12. After the pre-stored heat medium in the medium input pipeline 13 and the medium output pipeline 8 flows back to the high-temperature molten salt storage tank by gravity, then turn off the first valve assembly 14 and the second valve assembly 10, and the pre-stored unit is shut down.

[0081] In this embodiment, when it is predicted that the wind speed is high and the temperature is low at sunrise on the current day, that is, when the risk of pipe blockage is high, the tower solar energy heat absorption system can establish a self-circulation process between the heat absorber 4 and the high-temperature molten salt storage tank through the high-temperature molten salt reserved on the previous day (i.e., the pre-stored heat medium) before sunrise. At this time, if a pipe blockage occurs, the salt melting of the blocked part can be completed through the pre-stored heat medium (i.e., high-temperature molten salt) without the need for heliostat preheating. The temperature drop caused by the heat absorber 4 is supplemented by the electric heater 9. At sunrise, the salt melting of the blocked pipe of the heat absorber 4 is just completed, without increasing the light abandonment of the mirror field.

[0082] Embodiment 3

[0083] See Figure 1 , another core of the present invention is to provide an anti-freezing and anti-blocking method for a tower solar energy heat absorption system. Using the tower solar energy heat absorption system in Embodiment 1, the medium storage module 11 is a high-temperature medium storage tank, and the pre-stored heat medium is a high-temperature heat storage medium, including the following steps:

[0084] S1: At a predetermined time (i.e., the time set according to the weather conditions, or the start time set after judging the pipe blockage of the heat absorber 4, etc.), close the heat storage medium delivery unit and stop delivering the low-temperature heat storage medium to the heat absorber 4;

[0085] S2: Open the medium circulation module in the pre-storage unit to allow the pre-stored heat medium to flow into the heat absorber 4 and form a circulation between the medium storage module 11 and the heat absorber 4;

[0086] S3: After the pre-stored heat medium circulates in the heat absorber 4 for a predetermined time, judge whether a pipe blockage occurs inside according to the temperature of the thermocouples at various positions in the heat absorber 4;

[0087] S4: If it is judged that a pipe blockage occurs, turn on the heating module to heat the pre-stored heat medium until the salt melting at the blocked part is completed;

[0088] If it is judged that no pipe blockage occurs, turn on the heating module after the temperature of the pre-stored heat medium is lower than the preset temperature;

[0089] S5: After sunrise and after the heat absorber 4 receives the concentrated light from the heliostat mirror field, open the heat storage medium delivery unit and close the pre-storage unit.

[0090] As another optional but non-limiting implementation manner, specifically, see the appendix Figure 1 As shown, the heat storage medium is molten salt, the medium storage module 11 is a high-temperature molten salt storage tank, and the pre-stored heat medium is high-temperature molten salt; during the salt combing on the previous day, a part of the high-temperature pre-stored heat medium (i.e., high-temperature molten salt) is reserved in the high-temperature molten salt storage tank (i.e., the medium storage module 11), and the amount of this part of the pre-stored heat medium (i.e., high-temperature molten salt) is sufficient to circulate between the high-temperature molten salt storage tank and the heat absorber 4.

[0091] When it is predicted that the risk of tube blockage in the heat absorber 4 on the current day is relatively low, the tower-type solar heat absorption system can cooperate with the mirror field to complete the salt inlet work of the heat absorber 4 at sunrise. At this time, the anti-freezing and anti-blocking method of the tower-type solar heat absorption system includes the following steps:

[0092] S1: After sunrise, open the third valve assembly 2, close the fourth valve assembly 7, and at the same time, sequentially open the first valve assembly 14, the second valve assembly 10, and the medium pump 12. The pre-stored heat medium (i.e., high-temperature molten salt) enters the heat absorber 4 first compared with the low-temperature heat storage medium (i.e., low-temperature molten salt) under the tower, so that each tube screen of the heat absorber 4 is filled with the pre-stored heat medium (i.e., high-temperature molten salt).

[0093] S2: During the period when the liquid level of the outlet buffer tank 6 rises, judge whether there is tube blockage inside through the temperature at each position in the heat absorber 4.

[0094] S3: If it is judged that there is tube blockage, turn on the electric heater 9 to heat the pre-stored heat medium (i.e., high-temperature molten salt), maintain the temperature of the pre-stored heat medium (i.e., high-temperature molten salt) above 565 °C, and at the same time close the third valve assembly 2 until the salt at the blocked pipe is melted, then open the third valve assembly 2 and the fourth valve assembly 7, and close the medium pump 12, the first valve assembly 14, and the second valve assembly 10.

[0095] If it is judged that there is no tube blockage, open the fourth valve assembly 7, and close the medium pump 12, the first valve assembly 14, and the second valve assembly 10 (i.e., the pre-storage unit), and the heat storage medium delivery unit is started.

[0096] In this embodiment, when it is predicted that the risk of tube blockage in the heat absorber 4 on the current day is relatively low, the tower-type solar heat absorption system can cooperate with the mirror field to complete the salt inlet work of the heat absorber 4 at sunrise. If there is no tube blockage problem, the electric heater 9 is not started; if there is still tube blockage, the electric heater 9 is started, and a self-circulation of the heat absorber 4 is established through the pre-storage unit, completing the salt melting of the blocked pipe while reducing the plant electricity consumption.

[0097] Of course, in the afternoon on a cloudy day, it is impossible to judge the time when the clouds move away, and at the same time, there is a concern about wasting solar energy resources after the clouds move away. At this time, a self-circulation between the heat absorber 4 and the high-temperature molten salt storage tank can also be established by using the tower-type solar heat absorption system, and the electric heater 9 is stopped. If the clouds move away in the afternoon, start the heat storage medium delivery unit and couple the third valve assembly 2 and the pre-storage unit to operate. If the clouds do not move away in the afternoon, turn on the pre-storage unit to prevent freezing and blockage. Compared with the way of circulating and anti-freezing and anti-blocking of the heat storage medium delivery unit, a large amount of plant electricity consumption is saved.

[0098] Based on the unique principle of establishing a self - circulation of the heat storage medium at high temperature in the heat absorber 4 before sunrise, the present invention can carry out the salt - melting operation on the blocked pipeline of the heat absorber 4 in advance, effectively preventing the occurrence of pipe blockage in the heat absorber 4. That is, the self - circulation of the pre - stored heat storage medium in the heat absorber 4 can be realized before sunrise, ensuring that the heat absorber 4 can still maintain a good working state in a low - temperature environment, and avoiding equipment damage and production interruption caused by freezing blockage. At the same time, the present invention can directly provide the heat absorber 4 with a pre - stored heat storage medium at 565 °C. This high - temperature heat storage medium can significantly improve the salt - melting efficiency at the blocked pipe, quickly dredge the blocked pipeline, reduce the production stagnation time caused by pipe blockage, and improve the stability and reliability of the entire heat absorption system.

[0099] After sunrise, the present invention can directly make all heliostats project onto the heat absorber 4, without the need for the pre - heating and salt - melting links of the heat absorber 4. This improvement avoids the time consumed in the pre - heating and salt - melting processes in the traditional process, enables the heat absorber 4 to enter the normal working state faster, thereby increasing the effective absorption time of the heat absorber 4 for solar energy, significantly improving the utilization efficiency of solar energy resources, and contributing to increasing the overall power generation and economic benefits of the heat absorption system.

[0100] The pre - storage unit of the present invention is arranged on the conversion layer platform 15 of the tower body, and the distance from the heat absorber 4 is only 20 - 30 meters. Compared with the traditional setting of the medium conveying pipeline in a heat absorption tower of more than 200 meters, the distance has decreased by an order of magnitude. This close arrangement method greatly shortens the pipeline length of the medium circulation, reduces the resistance loss in the medium transportation process, and thus can significantly reduce the consumption of plant electricity in the pipe - blockage salt - melting stage of the heat absorber 4, reducing the operating cost of the heat absorption system.

[0101] The present invention does not need to change the existing process system and its pipeline materials, and has good compatibility and universality. This means that when using the present invention for technological upgrading, there is no need to carry out large - scale transformation and replacement of existing equipment, reducing the difficulty and cost of technology implementation. At the same time, it also reduces the risk of production interruption caused by equipment transformation, which is conducive to the rapid popularization and application of the present invention.

[0102] The embodiments of the present invention have been described in detail above with reference to the drawings, but the present invention is not limited to the above - mentioned embodiments. Even if various changes are made to the present invention, provided that these changes fall within the scope of the claims of the present invention and its equivalent technologies, they still fall within the protection scope of the present invention.

Claims

1. A tower solar heat absorption system, characterized in that, Including: A heat absorber, which is installed on a heat absorption tower; A heat storage medium conveying unit, which is configured to be able to input a low-temperature heat storage medium into the heat absorber and output the high-temperature heat storage medium after being heated by the heat absorber; A pre-storage unit, which is installed on the heat absorption tower. The pre-storage unit includes a medium storage module, a heating module and a circulation module, and a pre-stored heat storage medium is provided in the medium storage module; The circulation module is configured to be able to make the pre-stored heat storage medium circulate between the medium storage module and the heat absorber; The heating module is arranged in the medium storage module, and / or the heating module is arranged on the medium circulation module. The heating module is used to heat the pre-stored heat storage medium.

2. The tower solar energy heat absorption system according to claim 1, characterized in that, The medium circulation module includes a circulation pipeline and a medium driving component. The medium driving component is arranged on the circulation pipeline and is used to output the pre-stored heat storage medium in the medium storage module from the medium storage module.

3. The tower solar energy heat absorption system according to claim 2, characterized in that The circulation pipeline includes a medium input pipeline and a medium output pipeline; The first end of the medium input pipeline is connected to the medium input end of the medium storage module, and the second end of the medium input pipeline is connected to the medium output end of the heat absorber; The first end of the medium output pipeline is connected to the medium output end of the medium storage module, and the second end of the medium output pipeline is connected to the medium input end of the heat absorber; Wherein, a first valve assembly is arranged between the first end and the second end of the medium output pipeline, and a second valve assembly is arranged between the first end and the second end of the medium input pipeline.

4. The tower solar energy heat absorption system according to claim 3, characterized in that The heating module is an electric heater; The electric heater is arranged on the medium output pipeline, or the electric heater is arranged on the medium input pipeline; The medium driving component is a medium pump. The medium pump is arranged in the medium storage module and is communicated with the medium output end of the medium storage module.

5. The tower solar energy heat absorption system according to claim 1, wherein A conversion layer platform is arranged at the upper end of the heat absorption tower, and the pre-storage unit is arranged on the conversion layer platform.

6. The tower solar heat absorption system according to claim 3, characterized in that, The heat storage medium conveying unit includes a rising pipeline and a falling pipeline; The rising pipeline is connected to the medium input end of the heat absorber and is used to input low-temperature molten salt into the heat absorber; The falling pipeline is connected to the medium output end of the heat absorber and is used to output the high-temperature molten salt after being heated by the heat absorber; Wherein, the heat storage medium is molten salt, the medium storage module is a high-temperature molten salt storage tank, and the pre-stored heat storage medium is high-temperature molten salt.

7. The tower solar energy heat absorption system according to claim 6, wherein, The heat storage medium conveying unit further includes an inlet buffer tank and an outlet buffer tank; The rising pipeline is communicated with the input end of the inlet buffer tank, and the output end of the inlet buffer tank is connected to the medium input end of the heat absorber through a first pipeline; The falling pipeline is communicated with the output end of the outlet buffer tank, and the input end of the outlet buffer tank is connected to the medium output end of the heat absorber through a second pipeline; Wherein, the second end of the medium output pipeline is connected to the first pipeline, and the second end of the medium input pipeline is connected to the second pipeline; the heating module is installed on the medium input pipeline.

8. The tower-type solar energy heat absorption system according to claim 7, characterized in that A third valve assembly is provided on the riser pipeline, and a fourth valve assembly is provided on the downcomer pipeline; A fifth valve assembly is provided on the first pipeline, and the fifth valve assembly is arranged between the second end of the medium output pipeline and the medium input end of the heat absorber.

9. The tower solar energy heat absorption system according to any one of claims 1-8, characterized in that, It further includes a control unit and a plurality of thermocouples. The plurality of thermocouples are installed at various positions of the heat absorber, and the control unit is configured to control the tower solar heat absorption system based on the temperature information of the plurality of thermocouples.

10. A method for preventing freezing and blocking of a tower-type solar energy heat absorption system, characterized in that, Using the tower solar heat absorption system as claimed in claim 8, wherein the medium storage module is a high-temperature medium storage tank, and the pre-stored heat medium is a high-temperature heat storage medium, comprising the following steps: S1: At a predetermined time, close the heat storage medium delivery unit to stop delivering the low-temperature heat storage medium to the heat absorber; S2: Open the medium circulation module in the pre-storage unit to allow the pre-stored heat medium to flow into the heat absorber and form a circulation between the medium storage module and the heat absorber; S3: After the pre-stored heat medium circulates in the heat absorber for a predetermined time, determine whether a pipe blockage occurs inside the heat absorber based on the temperatures of the thermocouples at various positions inside the heat absorber; S4: If it is determined that a pipe blockage occurs, turn on the heating module to heat the pre-stored heat medium until the salt at the blocked pipe section is melted; If it is determined that no pipe blockage occurs, turn on the heating module after the temperature of the pre-stored heat medium is lower than the preset temperature; S5: After sunrise and when the heat absorber receives the concentrated light from the heliostat field, open the heat storage medium delivery unit and close the pre-storage unit.

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