Heat absorber for tower-type photo-thermal power station with heat absorbing pipes heated on two sides by sunlight

Abstract

The invention discloses a heat absorber for a tower-type photo-thermal power station with heat absorbing pipes heated on two sides by sunlight, and belongs to the technical field of tower-type solar thermal power generation. The heat absorber comprises a plurality of heat absorption tube panels which are tightly arranged on a heat absorption tower body through a fixing hole plate, each heat absorption tube panel comprises a plurality of heat absorption tubes to form a semi-arc structure, the concave side face of the structure is a first light receiving face, the convex side face of the structure is a second light receiving face, and sunlight is projected to the first light receiving face and the second light receiving face. The condensation field is arranged around the heat absorption tower, the first light receiving face and the second light receiving face can receive sunlight reflected by the heliostat, and the two sides of the heat absorption pipe are heated by the sunlight at the same time. The uniformity of heat flow density distribution on the surface of the heat absorption pipe is improved, the risk of thermal stress damage is reduced, the overall heat efficiency of the heat absorber is improved, and the equipment investment cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of tower solar thermal power generation, and particularly relates to a solar absorber for a tower-type solar thermal power station in which a heat absorption tube is heated on both sides by sunlight. Background Art

[0002] Solar thermal power generation is a green and low-carbon power source friendly to the power grid, with the dual functions of a peak shaving power source and energy storage, and can provide better long-term peak shaving capacity and moment of inertia for the power system.

[0003] According to different light concentration methods, solar thermal power generation technologies can be divided into parabolic trough type, tower type, linear Fresnel type and dish type. Among them, the tower-type solar thermal power generation technology has the advantages of high optical efficiency, high concentration ratio, high operating temperature, etc., and has good prospects for large-scale development. In a tower-type solar thermal power generation system, heliostats in the light concentration system reflect and converge sunlight onto the solar absorber at the top of the heat absorption tower. A heat transfer working medium (such as molten salt) flows through the solar absorber to absorb heat and increase the temperature, and then enters the energy storage system for storage or is dispatched to the power generation system for power generation. As a key part connecting the light concentration system and the energy storage system, the solar absorber is the core device for converting solar energy into heat energy. Its performance directly affects the power generation efficiency of the system, and its safety affects the operating hours of the power plant.

[0004] The solar absorber for a tower-type solar thermal power generation station generally consists of several heat absorption tube screens, and each tube screen consists of several heat absorption tubes. One side of the heat absorption tube faces the heat preservation layer arranged towards the heat absorption tower body, and the other side faces the external environment to receive the sunlight reflected by the mirror field, which is single-sided light reception. This single-sided heating heat absorption tube has obvious defects in practical applications: the single-sided heating method will cause uneven heat distribution in the heat absorption tube. For a solar absorber working in a harsh environment with a heat flux density as high as 1MW / m 2 In the case of the solar absorber in a harsh environment, it will bear extremely large non-uniform thermal stress in terms of structure, increasing the risk of material fatigue and affecting the safety and reliability of the system. In addition, the single-sided heating design often has higher requirements for the thermal conductivity of the material, which increases the cost to a certain extent; and only half of the surface of the heat absorption tube set is used for light reception and heating, and its utilization rate is low. Summary of the Invention

[0005] To solve the above technical problems, the invention adopts the following technical scheme: A solar absorber for a tower-type solar thermal power generation station in which a heat absorption tube is heated on both sides by sunlight, comprising: a plurality of heat absorption tube screens closely arranged on the heat absorption tower body through fixed orifice plates. Each heat absorption tube screen contains several heat absorption tubes, forming a semi-circular arc structure. The concave side of this structure is the first light-receiving surface, and the convex side is the second light-receiving surface. Sunlight is projected onto the first light-receiving surface and the second light-receiving surface. The concentrating field is arranged around the heat absorption tower. Both the first light-receiving surface and the second light-receiving surface can receive the sunlight reflected by the heliostats, and both sides of the heat absorption tube are heated by light reception simultaneously.

[0006] The present invention has the following beneficial effects:

[0007] By readjusting the structure of the heat absorber and optimizing the arrangement of the tube screens, the present invention adopts a heat absorber structure with a new non-closed shape (such as semi-circular arc, angled shape, double semi-circular arc, double angled shape, etc.), enabling the heat absorption tubes to be heated from both sides by sunlight. Compared with the existing heat absorbers used in tower-type solar thermal power plants, it effectively utilizes the entire surface area of the heat absorption tubes for daylighting and heat absorption. On the one hand, the heating form of the heat absorption tubes is changed from semi-circumferential heating and semi-circumferential adiabatic to full-circumferential heating, significantly reducing the non-uniformity of the circumferential heat load distribution of the heat absorption tubes, thereby reducing the temperature gradient and thermal stress of the heat absorption tubes, reducing the fatigue risk of the heat absorption tube materials, and greatly reducing the safety risk and improving the reliability. On the other hand, it retains the concentrator field surrounding arrangement form adopted by traditional tower-type solar thermal power plants and the basic structure of traditional heat absorption tube screens, without adding new design and processing costs. And under the condition of the same light-receiving area, the new heat absorber can theoretically reduce the number of heat absorption tubes by half, improve the utilization rate of the heat absorption tubes, and eliminate the thermal insulation materials arranged on the backlight side of the traditional heat absorber, greatly reducing the investment cost of the heat absorber. In terms of the assembly process, the present invention uses fixed orifice plates to combine several heat absorption tubes to form a heat absorption tube screen. The heat absorption tubes are not welded to each other, and only a limited number of lateral positions are restricted by the fixed orifice plates and fixed on the heat absorption tower body. This installation method leaves a safety margin for the thermal expansion of the heat absorption tubes, allowing the heat absorption tubes to have a small position offset longitudinally, and they can also return to their original positions due to the restriction of the fixed orifice plates after cooling. The present invention divides the heat absorption tubes into heat absorption tubes welded on the front side and heat absorption tubes welded on the back side, and they are arranged alternately in parallel. Their welding points with the upper header and the lower header are set at different bus positions of the header, which helps to avoid stress concentration on the surface of the header and greatly improves the equipment safety. Description of the Drawings

[0008] Figure 1 Isometric view of Embodiment 1 of the present invention, wherein, 1 - heat absorption tube screen, 2 - fixed orifice plate, Ⅰ - first light-receiving surface, Ⅱ - second light-receiving surface;

[0009] Figure 2Top view of Embodiment 1 of the present invention, where W1 - the heat absorption tube screen numbered 1 on the west side, W2 - the heat absorption tube screen numbered 2 on the west side, W3 - the heat absorption tube screen numbered 3 on the west side, W4 - the heat absorption tube screen numbered 4 on the west side, W5 - the heat absorption tube screen numbered 5 on the west side, W6 - the heat absorption tube screen numbered 6 on the west side, E1 - the heat absorption tube screen numbered 1 on the east side, E2 - the heat absorption tube screen numbered 2 on the east side, E3 - the heat absorption tube screen numbered 3 on the east side, E4 - the heat absorption tube screen numbered 4 on the east side, E5 - the heat absorption tube screen numbered 5 on the east side, E6 - the heat absorption tube screen numbered 6 on the east side, Ⅰ - the first light-receiving surface, Ⅱ - the second light-receiving surface, Q solar - sunlight;

[0010] Figure 3 Isometric view of Embodiment 2 of the present invention, where 1 - heat absorption tube screen, 2 - fixed orifice plate, Ⅰ - the first light-receiving surface, Ⅱ - the second light-receiving surface;

[0011] Figure 4 Top view of Embodiment 2 of the present invention, where W1 - the heat absorption tube screen numbered 1 on the west side, W2 - the heat absorption tube screen numbered 2 on the west side, W3 - the heat absorption tube screen numbered 3 on the west side, W4 - the heat absorption tube screen numbered 4 on the west side, W5 - the heat absorption tube screen numbered 5 on the west side, W6 - the heat absorption tube screen numbered 6 on the west side, E1 - the heat absorption tube screen numbered 1 on the east side, E2 - the heat absorption tube screen numbered 2 on the east side, E3 - the heat absorption tube screen numbered 3 on the east side, E4 - the heat absorption tube screen numbered 4 on the east side, E5 - the heat absorption tube screen numbered 5 on the east side, E6 - the heat absorption tube screen numbered 6 on the east side, Ⅰ - the first light-receiving surface, Ⅱ - the second light-receiving surface, Q solar - sunlight;

[0012] Figure 5 Isometric view of Embodiment 3 of the present invention, where 1 - heat absorption tube screen, 2 - fixed orifice plate;

[0013] Figure 6Top view of Embodiment 3 of the present invention, where W1 - the heat absorption tube screen numbered 1 located on the west side, W2 - the heat absorption tube screen numbered 2 located on the west side, W3 - the heat absorption tube screen numbered 3 located on the west side, W4 - the heat absorption tube screen numbered 4 located on the west side, W5 - the heat absorption tube screen numbered 5 located on the west side, W6 - the heat absorption tube screen numbered 6 located on the west side, E1 - the heat absorption tube screen numbered 1 located on the east side, E2 - the heat absorption tube screen numbered 2 located on the east side, E3 - the heat absorption tube screen numbered 3 located on the east side, E4 - the heat absorption tube screen numbered 4 located on the east side, E5 - the heat absorption tube screen numbered 5 located on the east side, E6 - the heat absorption tube screen numbered 6 located on the east side, Q solar - sunlight;

[0014] Figure 7 Isometric view of Embodiment 4 of the present invention, where 1 - heat absorption tube screen, 2 - fixed orifice plate;

[0015] Figure 8 Top view of Embodiment 4 of the present invention, where W1 - the heat absorption tube screen numbered 1 located on the west side, W2 - the heat absorption tube screen numbered 2 located on the west side, W3 - the heat absorption tube screen numbered 3 located on the west side, W4 - the heat absorption tube screen numbered 4 located on the west side, W5 - the heat absorption tube screen numbered 5 located on the west side, W6 - the heat absorption tube screen numbered 6 located on the west side, E1 - the heat absorption tube screen numbered 1 located on the east side, E2 - the heat absorption tube screen numbered 2 located on the east side, E3 - the heat absorption tube screen numbered 3 located on the east side, E4 - the heat absorption tube screen numbered 4 located on the east side, E5 - the heat absorption tube screen numbered 5 located on the east side, E6 - the heat absorption tube screen numbered 6 located on the east side, Q solar - sunlight;

[0016] Figure 9 Isometric side view of a single heat absorption tube screen of the present invention, where 2 - fixed orifice plate, 3 - upper header, 4 - lower header, 5 - heat absorption tubes welded on the front side, 6 - heat absorption tubes welded on the rear side, 7 - heat transfer working fluid inlet and outlet;

[0017] Figure 10 Front view of a single heat absorption tube screen of the present invention, where 2 - fixed orifice plate, 3 - upper header, 4 - lower header, 5 - heat absorption tubes welded on the front side, 6 - heat absorption tubes welded on the rear side, 7 - heat transfer working fluid inlet and outlet;

[0018] Figure 11 Right view of a single heat absorption tube screen of the present invention, where 2 - fixed orifice plate, 3 - upper header, 4 - lower header, 5 - heat absorption tubes welded on the front side, 6 - heat absorption tubes welded on the rear side, 7 - heat transfer working fluid inlet and outlet;

[0019] Figure 12Top view of the single-piece heat-absorbing tube screen of the present invention, where 2 is the fixed orifice plate, 3 is the upper header, 5 is the heat-absorbing tube welded on the front side, 6 is the heat-absorbing tube welded on the rear side, and 7 is the inlet / outlet of the heat-transfer working fluid;

[0020] Figure 13 Top view of the fixed orifice plate of the present invention, where 2 is the fixed orifice plate;

[0021] Figure 14 Schematic diagram of the heat-transfer working fluid flow of the present invention, where W1 is the heat-absorbing tube screen numbered 1 located on the west side, W2 is the heat-absorbing tube screen numbered 2 located on the west side, W3 is the heat-absorbing tube screen numbered 3 located on the west side, W4 is the heat-absorbing tube screen numbered 4 located on the west side, W5 is the heat-absorbing tube screen numbered 5 located on the west side, W6 is the heat-absorbing tube screen numbered 6 located on the west side, E1 is the heat-absorbing tube screen numbered 1 located on the east side, E2 is the heat-absorbing tube screen numbered 2 located on the east side, E3 is the heat-absorbing tube screen numbered 3 located on the east side, E4 is the heat-absorbing tube screen numbered 4 located on the east side, E5 is the heat-absorbing tube screen numbered 5 located on the east side, E6 is the heat-absorbing tube screen numbered 6 located on the east side, and 8 is the exhaust valve. Detailed implementation manners

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various implementation manners of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Embodiment 1:

[0024] Refer to Figure 1 and Figure 2 , the heat absorber for a tower-type solar thermal power plant in which the heat-absorbing tubes of the present invention are heated bilaterally by sunlight (hereinafter referred to as the heat absorber) includes: a plurality of heat-absorbing tube screens 1 closely arranged on the heat-absorbing tower body through a fixed orifice plate 2. Each heat-absorbing tube screen 1 contains several heat-absorbing tubes (the specific number is determined according to the capacity of the heat absorber, the size of the heat-absorbing tubes and the arrangement mode), forming a semi-circular arc structure. The concave side of this structure is the first light-receiving surface I, and the convex side is the second light-receiving surface II. The sunlight Q solarIt can be projected onto the first light-receiving surface Ⅰ and the second light-receiving surface Ⅱ. If the heat absorber includes 12 heat-absorbing tube screens 1 (it can also be other quantities, only an example here), name them according to the positions of the heat-absorbing tube screens 1 arranged in the heat absorber. Name the heat-absorbing tube screens on the west side with the letter W, and name the heat-absorbing tube screens on the east side with the letter E; sort them according to the flowing order of the heat transfer working medium, and number them with 1-6 to obtain the numbers of the 12 heat-absorbing tube screens 1, namely W1-W6 and E1-E6; the heat transfer working medium flows through each heat-absorbing tube screen 1 in 2 loops. The 6 heat-absorbing tube screens 1 in the same loop are connected in series, and the two loops are connected in parallel. Due to the particularity of sunlight heating, at other times except noon, the sunlight energy received by the heat-absorbing tube screens on the east side and the west side is different. In order to make the outlet temperatures of the heat transfer working medium in the two loops as the same as possible, each loop takes 3 east-side heat-absorbing tube screens and 3 west-side heat-absorbing tube screens, and cross pipelines are arranged between the 3 east-side heat-absorbing tube screens and the 3 west-side heat-absorbing tube screens to balance the sunlight energy difference between the east and west sides. In Embodiment 1, the heat transfer working medium in the two loops flows through all the heat-absorbing tube screens in the order of W1-W2-W3-E4-E5-E6 and E1-E2-E3-W4-W5-W6. The cross pipelines are arranged between W3 and E4, and between E3 and W4. In addition, the arrangement order of the heat-absorbing tube screens 1 is not limited to the way of Embodiment 1. Any other arrangement ways that can balance the sunlight energy difference between the east and west sides are acceptable. For example, the heat transfer working medium can also flow through all the heat-absorbing tube screens in the order of W1-W2-E3-E4-E5-E6 and E1-E2-W3-W4-W5-W6, and cross pipelines are arranged between each east-side heat-absorbing tube screen and west-side heat-absorbing tube screen.

[0025] See Figures 9 - 12 , the heat-absorbing tube screen 1 is composed of an upper header 3, a lower header 4, heat-absorbing tubes 5 welded on the front side, heat-absorbing tubes 6 welded on the rear side, heat transfer working medium inlets and outlets 7, and a fixed orifice plate 2; See Figure 13, the fixed orifice plate 2 is directly fixed on the heat absorption tower body. Inside the fixed orifice plate 2, round holes are reserved, and the total number of the round holes penetrating the fixed orifice plate 2 is the same as the total number of the heat absorption tubes 5 welded on the front side and the heat absorption tubes 6 welded on the rear side included in one heat absorption tube screen 1. The diameter of the round holes is 1 - 5 mm larger than the outer diameters of the heat absorption tubes 5 welded on the front side and the heat absorption tubes 6 welded on the rear side, leaving a certain margin for the thermal expansion of the heat absorption tubes, allowing the heat absorption tubes to have a small longitudinal position offset within the round holes of the fixed orifice plate 2. At the same time, after the heat absorption tubes cool down, they will return to their original positions due to the limitation of the transverse position by the round holes on the fixed orifice plate 2; the heat absorption tubes 5 welded on the front side and the heat absorption tubes 6 welded on the rear side have the same dimensions, generally with an outer diameter of 20 - 50 mm and a wall thickness of 1 - 2 mm, and are arranged side by side and alternately passing through the fixed orifice plate 2, and are connected to the upper header 3 and the lower header 4 using the welding process, and their welding points are located at different generatrix positions of the header to avoid stress concentration on the surface of the header; adjacent heat absorption tubes are not welded, and only the fixed orifice plate 2 restricts the limited number of transverse relative positions between the heat absorption tubes and the heat absorption tower body and fixes them on the heat absorption tower body; the heat transfer working fluid inlets and outlets 7 are arranged above the upper header 3 and below the lower header 4; see Figure 14 , an exhaust valve 8 is connected to the upper header 3 of the heat absorption tube screen 1 to discharge the gas generated inside the heat absorption tubes under high-temperature conditions and maintain the gas pressure inside the tubes within a safe level.

[0026] Preferably, the heat absorption tubes are made of nickel-based alloy materials, and a coating with weather resistance and high-temperature oxidation resistance (such as the selective absorption coating Pyromark®, with an absorptivity of 0.95 in the solar spectrum range and an emissivity of 0.83 in the infrared band) is applied to their outer surfaces, meeting the conditions of the invention that the absorptivity in the solar spectrum range ≥ 0.9 and the emissivity in the infrared band ≤ 0.85; the coating material can better absorb solar energy and at the same time reduce the radiation heat loss.

[0027] Preferably, the heat transfer working fluid is selected from water, steam or molten salt. In the present invention, solar salt (60% NaNO 3 - 40% KNO 3 ) is used as the heat transfer working fluid.

[0028] Preferably, see Figure 14 , the heat transfer working fluid flows through the heat absorber in two loops (the first row in the figure is the first loop, and the second row is the second loop) and is heated to raise the temperature. The heat absorption tube screens 1 in each loop are connected in series, and the two loops are in a parallel relationship; for the series-connected heat absorption tube screens 1, the flow direction of the heat transfer working fluid is arranged in a serpentine pattern (as shown by the arrows in the figure), and the flow directions of the heat transfer working fluid in adjacent heat absorption tube screens 1 are opposite.

[0029] Preferably, during the operation of the heat absorber, for the heat absorption tube bank 1 where the heat transfer working fluid flows from top to bottom: the heat transfer working fluid flows into from the heat transfer working fluid inlet / outlet 7 above the upper header 3, passes through the heat absorption tubes, and is heated and raised in temperature by the heat absorption tubes on the sunlight-irradiated surface. The heat transfer working fluid flows into the lower header 4 to mix and equalize the temperature of the heat transfer working fluid in each heat absorption tube, and flows out from the heat transfer working fluid inlet / outlet 7 below the lower header 4. solar The heat transfer working fluid is heated and raised in temperature by the heat absorption tubes on the sunlight-irradiated surface, flows into the lower header 4 to mix and equalize the temperature of the heat transfer working fluid in each heat absorption tube, and flows out from the heat transfer working fluid inlet / outlet 7 below the lower header 4.

[0030] For the heat absorption tube bank 1 where the heat transfer working fluid flows from bottom to top: the heat transfer working fluid flows into from the heat transfer working fluid inlet / outlet 7 below the lower header 4, passes through the heat absorption tubes, and the heat absorption tubes on the sunlight-irradiated surface are heated and raised in temperature. It flows into the upper header 3 to equalize the temperature of the heat transfer working fluid in each heat absorption tube, and flows out from the heat transfer working fluid inlet / outlet 7 above the upper header 3. solar The heat transfer working fluid is heated and raised in temperature by the heat absorption tubes on the sunlight-irradiated surface, flows into the upper header 3 to equalize the temperature of the heat transfer working fluid in each heat absorption tube, and flows out from the heat transfer working fluid inlet / outlet 7 above the upper header 3.

[0031] Preferably, cross pipelines are arranged between the east heat absorption tube bank and the west heat absorption tube bank included in each loop to balance the difference in solar radiation energy received by the heat absorption tube banks 1 in different orientations and maintain the outlet temperatures of the two loops at the same level. If the heat absorber includes 12 heat absorption tube banks 1 (it can also be other numbers of heat absorption tube banks, only an example here), they are named according to their positions in the heat absorber. The heat absorption tube banks on the west side are named with the letter W, and the heat absorption tube banks on the east side are named with the letter E. They are numbered from 1 to 6 according to the flowing order of the heat transfer working fluid, obtaining the 12 heat absorption tube bank numbers of W1 - W6 and E1 - E6. During the actual operation of the tower-type solar thermal power station, along with the movement of the sun's trajectory, there are significant temporal and spatial differences in the solar radiation illumination intensity received by the tube banks on the east and west sides of the heat absorber. The temporal difference can be balanced through the scheduling of the heliostats, while the spatial difference is balanced through the setting of the cross pipelines. The molten salts in the two loops flow through each heat absorption tube bank 1 and are heated in the order of W1, W2, W3, E4, E5, E6 and E1, E2, E3, W4, W5, W6 respectively.

[0032] Preferably, the concentrating solar field is arranged in a surrounding manner around the absorber tower. Both the first light-receiving surface Ⅰ and the second light-receiving surface Ⅱ can receive the sunlight reflected by the heliostats, and the two sides of the heat absorption tubes are heated simultaneously by light. Compared with the traditional heat absorber, the form of the heat absorption tubes changes from being heated on one side and insulated on the other side to being heated by sunlight on both sides. The molten salt in the tubes is heated more evenly, reducing the risk of structural stress damage caused by uneven heat loads. On the premise of the same light-receiving area, the number of heat absorption tubes used in the heat absorber of the present invention will only be half of the number of heat absorption tubes used in the traditional external cylindrical heat absorber.

[0033] Taking an existing typical tower-type solar thermal power plant as an example, the receiver used in this power plant is 6.2 m high and 5.2 m in diameter. It consists of 24 absorber tube screens, each absorber tube screen contains 32 absorber tubes, and the outer diameter of each absorber tube is 2.1 cm and the wall thickness is 1.2 mm. Based on this, the transformation is carried out, retaining the original absorber tube size and its arrangement form on the absorber tube screen, that is, retaining the structure and size of the whole absorber tube screen, and using the receiver for tower-type solar thermal power plants with absorber tubes heated by sunlight on both sides of the present invention, avoiding the design and processing costs brought by processing absorber tube screens with new sizes and structures; due to the special form of sunlight heating on both sides, at this time, only 12 absorber tube screens identical to the traditional receiver are needed to ensure that the light-receiving area of the receiver remains unchanged, saving half of the consumption of absorber tube materials and eliminating the thermal insulation materials used in the traditional receiver.

[0034] Preferably, the first light-receiving surface Ⅰ and the second light-receiving surface Ⅱ need to be adjusted according to the heat load intensity distribution provided by the concentrating field to ensure that the absorber tubes are heated as evenly as possible. When the tower-type solar thermal power generation system is located in the Northern Hemisphere, the first light-receiving surface Ⅰ faces the south mirror field, and the second light-receiving surface Ⅱ faces the north mirror field; when the tower-type solar thermal power generation system is located in the Southern Hemisphere, the first light-receiving surface Ⅰ faces the north mirror field, and the second light-receiving surface Ⅱ faces the south mirror field. The above light-receiving surface orientation arrangement scheme is aimed at the mirror field arrangement habit of the traditional tower-type solar thermal power generation system. In fact, for the receiver for tower-type solar thermal power plants with absorber tubes heated by sunlight on both sides of the present invention, on the basis of the traditional mirror field, the number of heliostats arranged on the east and west sides can be reduced, and the number of heliostats arranged on the north and south sides can be increased to achieve the beneficial effects of improving the optical efficiency of the mirror field, the utilization rate of heliostats and the truncation efficiency of the receiver as much as possible.

[0035] The above semi-circular arc structure is a structure closest to the traditional external cylindrical receiver. On the basis of the circular closed shape of the traditional receiver, half of the absorber tube screen is removed along the diameter, and the remaining absorber tube screens are arranged in a semi-circular arc structure. Its advantages are: the modification to the traditional receiver structure is small, so the existing engineering experience of external cylindrical receivers for tower-type solar thermal power plants can be fully utilized to guide the installation process, reducing the dependence on new technologies. Due to the small design changes, its maintenance work will not increase too much additional complexity and cost.

[0036] Example 2:

[0037] See Figure 3 、 Figure 4 , a receiver for tower-type solar thermal power plants with absorber tubes heated by sunlight on both sides. The absorber tube screen 1 is closely arranged on the absorber tower body through the fixed orifice plate 2 to form a folded-angle structure. The concave side of this structure is the first light-receiving surface Ⅰ, and the convex side is the second light-receiving surface Ⅱ. The technical principle and implementation specifications of Example 2 are the same as or similar to those of Example 1, and will not be elaborated here.

[0038] The above-mentioned angled structure is an optimization of the semi-circular arc structure in Embodiment 1. In Embodiment 2, an angled structure is adopted. The heat-absorbing tube screens located on the east and west sides respectively form two flat heat absorbers (one group is W1 - W6, and the other group is E1 - E6), which are connected at the angled part to jointly form the angled heat absorber in Embodiment 2. Its advantages are as follows: The angled structure can be manufactured through a straight angle, which is relatively easier to process than the semi-circular arc structure; due to the simple structure of the angled shape and its ease of assembly and disassembly, this design is more convenient and has lower costs during daily maintenance and inspection; during the actual application process, the size of the angle can be adjusted according to the mirror field layout and the incident angle of sunlight, etc. (within the range of 90 - 180°), which is more flexible and has greater development potential.

[0039] Embodiment 3:

[0040] See Figure 5 、 Figure 6 A heat absorber for a tower-type solar thermal power station in which a heat-absorbing tube is heated by sunlight on both sides. The heat-absorbing tube screen 1 is closely arranged on the heat-absorbing tower body through a fixed orifice plate 2 to form a double semi-circular arc structure. The differences between this structure and those in Embodiment 1 and Embodiment 2 are as follows: In Embodiment 3, there are multiple concave sides and convex sides, and the whole is centrosymmetric. Therefore, it is no longer necessary to label and distinguish with the first light-receiving surface Ⅰ and the second light-receiving surface Ⅱ, and there is no need to adjust the orientation of the heat absorber according to the heat load intensity distribution provided by the concentrating field. However, due to the long-standing habit of arranging the north-south mirror field, the semi-circular arc sides of the heat absorber can still be oriented towards the south and the north respectively, and it is not recommended to face the east and the west. Specific adjustments should be made in combination with the mirror field design situation.

[0041] The above-mentioned double semi-circular arc structure in Embodiment 3 is an optimization of the semi-circular arc structure in Embodiment 1. Embodiment 3 adopts a structure in which two semi-circular arcs with smaller diameters are connected in the reverse direction, and the closely arranged heat-absorbing tube screens 1 form a centrosymmetric shape. Its advantages are as follows: The overall design of the heat absorber is more compact. In an environment with strong high-altitude wind, it can better disperse the load exerted by the wind, avoiding the problem of structural instability caused by unbalanced forces; its centrosymmetric structure effectively eliminates the difference in sunlight input to the heat-absorbing tube screens 1 at different positions due to the north-south mirror field difference, making the surface heat loads of the two circuits in the heat absorber almost the same, and there is no need to consider the orientation of each light-receiving surface of the heat absorber anymore.

[0042] Embodiment 4:

[0043] See Figure 7 and Figure 8, a solar receiver for a tower-type solar thermal power station in which the heat absorption tube is heated on both sides by sunlight. The heat absorption tube screen 1 is closely arranged on the heat absorption tower body through the fixed orifice plate 2 to form a double-folded angle structure. The technical principle and implementation specification of this embodiment are the same as or similar to those of Embodiment 3, and will not be elaborated here.

[0044] The above double-folded angle structure is the combination of the advantages of Embodiment 2 and Embodiment 3. The double-folded angle structure of this embodiment is composed of a group of large flat solar receivers in the middle (formed by the heat absorption tube screens numbered W4-W6 and E4-E6) and a group of small flat solar receivers on each side (respectively formed by the heat absorption tube screens numbered W1-W3 and E1-E3), a total of three groups of flat solar receivers. The large flat solar receiver and the adjacent small flat solar receivers on both sides form angles respectively. Embodiment 4 is overall in a centrosymmetric shape. It combines the advantages of Embodiment 2 and Embodiment 3, and will not be elaborated here.

[0045] The quantity, etc. of the heat absorption tube screens 1 included in each of the above embodiments are only examples and are not used to limit the present invention.

Claims

1. A heat absorber for a tower-type solar thermal power station in which a heat absorbing tube is heated on both sides by sunlight, characterized in that: include: A plurality of heat absorbing tube screens (1) are closely arranged on a heat absorbing tower body through a fixed orifice plate (2), each heat absorbing tube screen (1) contains a plurality of heat absorbing tubes, forming a semicircular arc structure, the concave side of the structure is a first light receiving surface (I), and the convex side is a second light receiving surface (II), sunlight is projected onto the first light receiving surface (I) and the second light receiving surface (II), a focusing field is arranged around the heat absorbing tower, the first light receiving surface (I) and the second light receiving surface (II) can both receive sunlight reflected by the heliostat, and both sides of the heat absorbing tube are heated by light at the same time.

2. The heat absorber for a tower-type solar thermal power station with a heat absorbing tube heated by sunlight on both sides according to claim 1, characterized in that: The heat absorbing tube panel (1) comprises an upper header (3), a lower header (4), a heat absorbing tube (5) welded on the front side, a heat absorbing tube (6) welded on the rear side, a heat transfer medium inlet and outlet (7), and a fixed orifice plate (2); the heat absorbing tube (5) welded on the front side and the heat absorbing tube (6) welded on the rear side are connected to the upper header (3) and the lower header (4) respectively located at the upper end and the lower end of the heat absorbing tube panel (1); the heat transfer medium inlet and outlet (7) are arranged above the upper header (3) and below the lower header (4); the fixed orifice plate (2) is fixed on the heat absorbing tower body, and the heat absorbing tube (5) welded on the front side and the heat absorbing tube (6) welded on the rear side are arranged inside.

3. The absorber for a tower-type solar thermal power station with a heat absorbing tube heated on both sides by sunlight according to claim 2, characterized in that: The fixed orifice plate (2) is internally reserved with circular holes penetrating the fixed orifice plate (2), the number of which is the same as the total number of the front-side welded heat absorption tubes (5) and the rear-side welded heat absorption tubes (6) contained in a heat absorption tube panel (1), and the diameter of the circular holes is 1-5 mm larger than the outer diameter of the front-side welded heat absorption tubes (5) and the rear-side welded heat absorption tubes (6).

4. The absorber for a tower-type solar thermal power station with a heat absorbing tube heated on both sides by sunlight according to claim 3 is characterized in that: The heat absorbing tubes (5) welded on the front side and the heat absorbing tubes (6) welded on the rear side have the same size, are arranged in parallel and alternately, pass through the fixed orifice plate (2), and are connected to the upper header (3) and the lower header (4) using a welding process, with the welding points being located at different busbar positions of the headers; adjacent heat absorbing tubes are not welded, and are only limited to a limited number of lateral positions by the fixed orifice plate (2), and are fixed on the heat absorbing tower body.

5. The heat absorber for a tower-type solar thermal power station with a heat absorbing tube heated on both sides by sunlight according to claim 4, characterized in that: The upper header (3) of the heat absorbing tube panel (1) is connected to an exhaust valve (8) for exhausting gas generated in the heat absorbing tube under high temperature conditions and maintaining the gas pressure in the tube within a safe level.

6. The absorber for a tower-type solar thermal power station with a heat absorbing tube heated on both sides by sunlight according to claim 1, characterized in that: The heat absorbing tube is made of nickel-based alloy material, and its outer surface is coated with a coating having weather resistance and high temperature oxidation resistance.

7. The heat absorber for a tower-type solar thermal power station with a heat absorbing tube heated on both sides by sunlight according to claim 1, characterized in that: The heat transfer medium is water, water vapor or molten salt.

8. The heat absorber for a tower-type solar thermal power station with a heat absorbing tube heated on both sides by sunlight according to claim 1, characterized in that: The multiple heat absorption tube panels (1) are divided into multiple east heat absorption tube panels and multiple west heat absorption tube panels according to the installation position; the heat transfer medium is divided into two loops and flows through the heat absorber to be heated to increase the temperature, the heat absorption tube panels (1) in each loop are connected in series, the two loops are in a parallel relationship, and each loop includes a plurality of east heat absorption tube panels and the same number of west heat absorption tube panels; the flow direction of the heat transfer medium in the series-connected heat absorption tube panels (1) is arranged in a serpentine shape, the flow direction of the heat transfer medium in adjacent heat absorption tube panels (1) is opposite, and a cross pipeline is arranged between the east heat absorption tube panel and the west heat absorption tube panel contained in each loop.

9. The heat absorber for a tower-type solar thermal power station with a heat absorbing tube heated by sunlight on both sides according to claim 1, characterized in that: The heat absorption tube panel (1) is closely arranged on the heat absorption tower body through the fixed orifice plate (2) to form an angled structure, wherein the concave side surface of the angled structure is the first light receiving surface (I), and the convex side surface is the second light receiving surface (II); the heat absorption tube panel (1) is closely arranged on the heat absorption tower body through the fixed orifice plate (2) to form a double semicircular arc structure, which is centrally symmetrical as a whole; the heat absorption tube panel (1) is closely arranged on the heat absorption tower body through the fixed orifice plate (2) to form a double angled structure, which is centrally symmetrical as a whole.

10. The heat absorber for a tower-type solar thermal power station with a heat absorber tube heated on both sides by sunlight according to claim 1, characterized in that: The double-angle structure consists of three groups of flat plate heat absorbers, namely a group of large flat plate heat absorbers in the middle and a group of small flat plate heat absorbers on both sides. The large flat plate heat absorber and the small flat plate heat absorbers adjacent to both sides form angles respectively.

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