Solar heat collection device and design method

Abstract

The invention provides a solar heat collection device and a design method, and belongs to the field of heat collection devices. The solar heat collection device comprises a biomass gasification reaction tube, a heat collection mirror, a reaction tube supporting rod and a base; the heat collecting mirror is rotatably connected with the base, and the biomass gasification reaction tube is connected with the heat collecting mirror through a plurality of reaction tube supporting rods; the biomass gasification reaction tube comprises a reaction tube body, a heat absorption layer and a heat storage layer, the periphery of the reaction tube body is coated with the heat storage layer, the periphery of the heat storage layer is coated with the heat absorption layer, and the end, away from the heat collection mirror, of each reaction tube supporting rod is connected with the heat absorption layer. The invention aims to solve the problems of insufficient heat collection temperature, non-uniform heat transfer and the like in the process of driving biomass gasification reaction by a solar heat collection device in the prior art. The solar heat collector has the advantages that heat collection temperature is guaranteed, and meanwhile uniform-temperature heat transfer is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat collection devices, in particular to a solar heat collection device, and also to a design method of a solar heat collection device. Background Art

[0002] The energy crisis has become a global problem. Conventional fossil energy reserves are limited and non-renewable, and the use of fossil energy has also caused serious environmental pollution and ecological damage. The transformation of energy structure is imperative. Therefore, how to reasonably develop and utilize renewable energy has become a new issue facing mankind since entering the 21st century.

[0003] Among many renewable energy sources, solar energy and biomass energy are widely used. As a renewable new energy source, solar energy has the advantages of being clean, environmentally friendly, sustainable and long-lasting, and has become one of the important choices for people to deal with energy shortages, climate change and energy conservation and emission reduction. Biomass energy is the energy form of solar energy stored in biomass in the form of chemical energy. It comes directly or indirectly from the photosynthesis of green plants and can be converted into conventional solid, liquid and gaseous fuels. It is inexhaustible. Biomass energy has always been an important energy source for human survival. It is the fourth largest energy source in the world in terms of total energy consumption after coal, oil and natural gas, and occupies an important position in the entire energy system.

[0004] The utilization of solar energy is mainly concentrated in the fields of solar thermal utilization and solar power generation. Solar thermal utilization projects mainly include solar water heaters, solar houses, solar cookers, heating and air conditioning, refrigeration, solar drying and industrial heat. Solar power generation mainly includes solar thermal power generation and solar photovoltaic power generation. Solar thermal power generation is a technology that uses concentrating collectors to convert solar radiation energy into thermal energy and continuously generate electricity through thermal cycles. There are mainly different forms of demonstration devices such as tower systems, trough systems and dish systems. Among them, trough technology is relatively more mature. However, the current trough technology has problems such as insufficient heat collection temperature and uneven heat transfer during the solar-driven biomass gasification reaction. Summary of the invention

[0005] The present invention provides a solar thermal collector and a design method, which are used to solve the defects of insufficient heat collection temperature and uneven heat transfer in the process of driving biomass gasification reaction by solar thermal collector in the prior art, and realize uniform temperature heat transfer while ensuring the heat collection temperature.

[0006] A first aspect of the present invention provides a solar heat collection device, comprising a biomass gasification reaction tube, a heat collecting mirror, a reaction tube support rod and a base; The heat collecting mirror is rotatably connected to the base, and the biomass gasification reaction tube is connected to the heat collecting mirror through a plurality of reaction tube support rods; The biomass gasification reaction tube includes a reaction tube body, a heat absorption layer and a heat storage layer. The outer periphery of the reaction tube body is coated with the heat storage layer, and the outer periphery of the heat storage layer is coated with the heat absorption layer. One end of each reaction tube support rod away from the heat collecting mirror is connected to the heat absorption layer.

[0007] In addition, the solar thermal collector according to the present invention may also have the following additional technical features: In some embodiments of the present invention, the biomass gasification reaction tube further includes an isolation layer, and the isolation layer is disposed between the reaction tube body and the heat storage layer.

[0008] In some embodiments of the present invention, the biomass gasification reaction tube further includes a uniform heating layer, and the uniform heating layer is arranged between the reaction tube body and the isolation layer.

[0009] In some embodiments of the present invention, a motor and a mounting shell are further included. The mounting shell is installed in the middle of the base, the motor is installed in the mounting shell, and the output shaft of the motor is connected to the heat collecting mirror.

[0010] In some embodiments of the present invention, a connecting seat is further included, one side of the connecting seat is connected to the heat collecting mirror, and the output shaft of the motor is connected to the other side of the connecting seat.

[0011] In some embodiments of the present invention, a bottom plate is further included, and the connecting seat is connected to the heat collecting mirror via the bottom plate.

[0012] In some embodiments of the present invention, a first splint and a second splint are further included, a plurality of first splints are arranged at intervals on the outer side of the heat collecting mirror, a plurality of second splints are arranged at intervals on the inner wall of the heat collecting mirror, the bottom plate is connected to the heat collecting mirror through the plurality of first splints, and one end of each reaction tube support rod facing away from the biomass gasification reaction tube is connected to a second splint.

[0013] In some embodiments of the present invention, a pipe sleeve is further included, and each reaction tube support rod is connected to the biomass gasification reaction tube through the pipe sleeve.

[0014] The second aspect of the present invention provides a design method for a solar thermal collector, which uses all the technical features of the solar thermal collector of the first aspect of the present invention, and in addition, further comprises the following steps: Step S100: selecting materials for the reaction tube body, heat absorption layer, heat storage layer, isolation layer and heat uniforming layer of the biomass gasification reaction tube with reference to the biomass gasification reaction conditions; Step S200: Dimensions of the reaction tube body, the heat absorption layer, the heat storage layer, the isolation layer and the heat uniforming layer of the biomass gasification reaction tube; Step S300: determining the size of the heat collecting mirror and each reaction tube support rod; Step S400: determining the arrangement of the heat collecting mirrors and the biomass gasification reaction tubes; Step S500: Establishing a model and analyzing the reaction conditions of biomass gasification; Step S600: Design is completed.

[0015] In some embodiments of the present invention, in step S500, the method of establishing a model and analyzing the biomass gasification reaction conditions includes the following steps: Step S510: Establishing a finite element analysis model with reference to biomass gasification reaction conditions; Step S520: using Soltrace software to simulate and obtain a ray tracing diagram of the solar thermal collector; Step S530: using Comsol software to establish a heat transfer model of the solar thermal collector; Step S540: Analyze the heat transfer model.

[0016] In summary, the present application includes the following beneficial technical effects: First, the heat collecting mirror can accurately reflect and focus sunlight onto a long and thin focal line through its parabolic shape design. This focusing effect significantly increases the energy density of sunlight, so that the biomass gasification reaction tube located on the focal line can more effectively absorb and utilize solar energy. Since sunlight is efficiently focused, the biomass gasification reaction tube located on the focal line can heat up quickly, thereby improving the efficiency of converting solar energy into thermal energy.

[0017] Second, the light and heat reflected by the heat collecting mirror are transferred to the heat storage layer for heat collection, so that the working medium of the heat absorption layer, the halogenated molten salt, melts. The large-pore foam metal of the heat storage layer strengthens the heat transfer and accelerates the phase change rate of the molten salt in the heat absorption layer. The melted molten salt of the heat absorption layer can flow in the pores of the foam metal of the heat storage layer to achieve uniform temperature heat transfer.

[0018] Thirdly, by rotatably connecting the heat collecting mirror and the base, the heat collecting device can collect heat according to the direction of the sun to ensure the heat collecting temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 A perspective view of a solar thermal collection device according to some embodiments of the present invention is schematically shown.

[0020] Figure 2 The cross-sectional view of the biomass gasification reaction tube of the solar thermal collection device according to some embodiments of the present invention is schematically shown.

[0021] Figure 3 A perspective view schematically shows a motor of a solar thermal collector according to some embodiments of the present invention installed on a base.

[0022] Figure 4 A perspective view schematically shows a base of a solar thermal collector according to some embodiments of the present invention.

[0023] Figure 5 A schematic diagram of the network division of a finite element model of a biomass gasification reaction tube in a design method of a solar thermal collector according to some embodiments of the present invention is schematically shown.

[0024] Figure 6 A schematic diagram of Mises stress distribution of a biomass gasification reaction tube of a solar thermal collector according to some embodiments of the present invention is schematically shown.

[0025] Figure 7 A schematic diagram of focusing solar energy rays according to a design method of a solar thermal collector device according to some embodiments of the present invention is schematically shown.

[0026] Figure 8 The schematic diagram of the temperature field distribution when the biomass gasification reaction tube is in steady-state heat collection in the design method of the solar thermal collection device according to some embodiments of the present invention is schematically shown.

[0027] Fig. 9 The internal gasification temperature distribution diagram of the biomass gasification reaction tube in the design method of the solar thermal collector according to some embodiments of the present invention is schematically shown.

[0028] Fig.10 The temperature distribution diagram of different cross sections of the biomass gasification reaction tube in the design method of the solar thermal collector according to some embodiments of the present invention is schematically shown.

[0029] Fig.11 The temperature distribution diagram of the outlet cross section of the biomass gasification reaction tube in the design method of the solar thermal collector according to some embodiments of the present invention is schematically shown.

[0030] Fig.12 The diagram schematically shows the pressure distribution of the biomass gasification medium fluid in the biomass gasification reaction tube in the design method of the solar thermal collector according to some embodiments of the present invention.

[0031] Fig.13 The diagram schematically shows the concentration distribution of hydrogen and carbon monoxide in biomass in the design method of a solar thermal collector according to some embodiments of the present invention.

[0032] Reference numerals: 1. Biomass gasification reaction tube, 11. Heat absorption layer, 12. Heat storage layer, 13. Isolation layer, 14. Heat uniformity layer, 15. Reaction tube body, 16. Biomass, 2. Heat collecting mirror, 3. Reaction tube support rod, 4. First splint, 5. Second splint, 6. Bottom plate, 7. Connecting seat, 8. Base, 81. Mounting shell, 9. Pipe sleeve, 10. Motor. DETAILED DESCRIPTION

[0033] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0034] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0035] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0036] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is flipped, then the element described as "below other elements or features" or "below other elements or features" will be subsequently oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be additionally oriented and rotated 90 degrees or in other directions and the spatial relative descriptors used in the text are interpreted accordingly.

[0037] like Figures 1 to 4 As shown, according to an embodiment of the first aspect of the present invention, a solar thermal collector is provided, comprising a biomass gasification reaction tube 1, a heat collecting mirror 2, a reaction tube support rod 3 and a base 8; The heat collecting mirror 2 is rotatably connected to the base 8, and the biomass gasification reaction tube 1 is connected to the heat collecting mirror 2 through a plurality of reaction tube support rods 3; The biomass gasification reaction tube 1 includes a reaction tube body 15, a heat absorption layer 11 and a heat storage layer 12. The outer periphery of the reaction tube body 15 is coated with the heat storage layer 12, and the outer periphery of the heat storage layer 12 is coated with the heat absorption layer 11. One end of each reaction tube support rod 3 away from the heat collecting mirror 2 is connected to the heat absorption layer 11.

[0038] In the above embodiment, it should be noted that the heat absorption layer 11 is made of molten salt, the reaction tube body 15 is made of high-strength alloy seamless steel pipe, the heat storage layer 12 is made of copper foam metal material with a porosity of 50%, the diameter of the pipe mouth of the biomass gasification reaction tube 1 is 2400mm, the length of the biomass gasification reaction tube 1 is 3500mm, biomass 16 is arranged in the reaction tube body 15, the minimum inner diameter of the reaction tube body 15 is 400mm, the thickness of the heat absorption layer 11 is 1500mm, and the thickness of the heat storage layer 12 is 300mm; the heat collecting mirror 2 is a trough-type solar focusing heat collecting mirror; the heat collecting device is realized by the setting that the heat collecting mirror 2 is rotatably connected to the base 8. The device can rotate with the direction of the sun rising in the east and setting in the west. When the sun rises from the east in the morning, the heat collecting mirror 2 of the heat collecting device rotates to a position facing the east and drives the biomass gasification reaction tube 1 to rotate to a position facing the east to meet the maximum range of solar energy absorption; when the sun is located in the south at noon, the heat collecting mirror 2 of the heat collecting device rotates to a position facing the south and drives the biomass gasification reaction tube 1 to rotate to a position facing the south to meet the maximum range of solar energy absorption; when the sun is located in the west in the afternoon, the heat collecting mirror 2 of the heat collecting device rotates to a position facing the west and drives the biomass gasification reaction tube 1 to rotate to a position facing the west to meet the maximum range of solar energy absorption.

[0039] Water vapor is introduced into the reaction tube body 15 as a gasification medium, and there is no need to introduce an oxidizing medium such as air or pure oxygen. The reaction formula mainly includes the synthesis gas reaction of the gasification subsystem of solar energy and biomass 16. The specific reaction formulas are mainly the following: Reaction 1: C+H2O→CO+H2△Hr, 298k=131.29KJ / mol (1) Reaction equation 2: C+CO2→2CO△Hr, 298k=172.46KJ / mol (2) Reaction equation 3: C+2H2→CH4△Hr, 298k=-74.81KJ / mol (3) Reaction 4: CH4+H2O→CO+3H2△Hr, 298k=206.10KJ / mol Reaction 5: CO + H2O → CO2 + H2△Hr, 298k = -41.17KJ / mol (5) The technical effects achieved by the above embodiment are as follows: First, the heat collecting mirror 2 can accurately reflect and focus sunlight onto a long and narrow focal line through its parabolic shape design. This focusing effect significantly increases the energy density of sunlight, so that the biomass gasification reaction tube 1 located on the focal line can absorb and utilize solar energy more effectively. Since the sunlight is efficiently focused, the biomass gasification reaction tube 1 located on the focal line can heat up rapidly, thereby improving the efficiency of converting solar energy into thermal energy; second, the light and heat reflected by the heat collecting mirror 2 are transferred to the heat storage layer 12 for heat collection, so that the working medium halogenated molten salt of the heat absorption layer 11 melts, and the foam metal of the large-aperture heat storage layer 12 strengthens heat transfer and accelerates the phase change rate of the molten salt of the heat absorption layer 11; the molten salt of the melted heat absorption layer 11 can flow in the pores of the foam metal of the heat storage layer 12 to achieve uniform temperature heat transfer; third, the setting of the rotatable connection between the heat collecting mirror 2 and the base 8 realizes that the heat collection device can collect heat according to the direction of the sun to ensure the heat collection temperature.

[0040] Optional, such as Figure 2 As shown, the biomass gasification reaction tube 1 further includes an isolation layer 13 , and the isolation layer 13 is arranged between the reaction tube body 15 and the heat storage layer 12 .

[0041] In the above optional embodiment, it should be noted that the thickness of the isolation layer 13 is 100 mm, and the isolation layer 13 is made of metal material.

[0042] Optional, such as Figure 2 As shown, the biomass gasification reaction tube 1 further includes a uniform heat layer 14 , and the uniform heat layer 14 is disposed between the reaction tube body 15 and the isolation layer 13 .

[0043] In the above optional embodiment, it should be noted that the uniform heating layer 14 is made of foam metal material; the thickness of the uniform heating layer 14 is 250 mm; and the uniform heating layer 14 is a heat transfer layer.

[0044] The beneficial effects of the above optional embodiments are: the isolation layer 13 separates the heat storage layer 12 from the uniform heat layer 14, preventing the molten salt of the melted heat absorption layer 11 from flowing into the uniform heat layer 14 and causing failure; the second uniform temperature heat transfer is achieved by the setting of the uniform heat layer 14.

[0045] Optional, such as Figure 1 , Figure 3 and Figure 4 As shown, it also includes a motor 10 and a mounting shell 81 . The mounting shell 81 is installed in the middle of the base 8 . The motor 10 is installed in the mounting shell 81 . The output shaft of the motor 10 is connected to the heat collecting mirror 2 .

[0046] In the above optional embodiments, it should be noted that the motor 10 is located at the center of the thermal collector mirror 2, and the output shaft of the motor 10 is connected to the thermal collector mirror 2 by screwing, welding or snapping; the motor 10 is connected to the mounting shell 81 by screwing, welding or snapping.

[0047] The beneficial effect of the above optional embodiment is that reliable rotation of the heat collecting mirror 2 relative to the base 8 is achieved through the provision of the motor 10 .

[0048] Optional, such as Figure 1 , Figure 3 and Figure 4 As shown, it also includes a connecting seat 7, one side of the connecting seat 7 is connected to the heat collecting mirror 2, and the output shaft of the motor 10 is connected to the other side of the connecting seat 7.

[0049] In the above optional embodiment, it should be noted that the cross-sectional shape of the connecting seat 7 is a “C” shape.

[0050] Optional, such as Figure 1 , Figure 3 and Figure 4 As shown, it also includes a bottom plate 6, and the connecting seat 7 is connected to the heat collecting mirror 2 through the bottom plate 6.

[0051] Optional, such as Figure 1 As shown, it also includes a first splint 4 and a second splint 5. A plurality of first splints 4 are arranged at intervals on the outer side of the heat collecting mirror 2, and a plurality of second splints 5 are arranged at intervals on the inner wall of the heat collecting mirror 2. The bottom plate 6 is connected to the heat collecting mirror 2 through the plurality of first splints 4, and one end of each reaction tube support rod 3 facing away from the biomass gasification reaction tube 1 is connected to a second splint 5.

[0052] In the above optional embodiments, it should be noted that each first clamp 4 is connected to the base plate 6 by means of screwing or welding, and the base plate 6 is connected to the connecting seat 7 by means of screwing, welding, riveting or bonding; each first clamp 4 is connected to the heat-collecting mirror 2 by means of screwing, welding, riveting or bonding, and each second clamp 5 is connected to the heat-collecting mirror 2 by means of screwing, welding, riveting or bonding; the reaction tube support rod 3 and the second clamp 5 are connected one by one by means of screwing, welding or clamping; the shape of each first clamp 4 and the shape of each second clamp 5 are both arc-shaped, and the upper surface of the base plate 6 is arc-shaped.

[0053] The beneficial effect of the above optional embodiment is that reliable connection between the heat collecting mirror 2 and the biomass gasification reaction tube 1 and between the heat collecting mirror 2 and the bottom plate 6 is achieved through the arrangement of the first clamping plate 4 and the second clamping plate 5 .

[0054] Optional, such as Figure 2 and Figure 3As shown, it also includes a pipe sleeve 9, and each reaction tube support rod 3 is connected to the biomass gasification reaction tube 1 through the pipe sleeve 9.

[0055] In the above optional embodiments, it should be noted that the biomass gasification reaction tube 1 is inserted into a plurality of pipe sleeves 9 in sequence along the axial direction. After the insertion is completed, each pipe sleeve 9 is connected to the biomass gasification reaction tube 1 by welding, bonding, or clamping, and each pipe sleeve 9 is connected to the corresponding reaction tube support rod 3 by screwing, welding, clamping, or bonding.

[0056] The beneficial effect of the above optional embodiment is that the reliability of the installation of the biomass gasification reaction tube 1 is ensured by the arrangement of the tube sleeve 9 .

[0057] According to an embodiment of the second aspect of the present invention, Figures 5 to 13 As shown, a design method for a solar thermal collector is proposed, using all the technical features of the solar thermal collector of the embodiment of the first aspect of the present invention, and in addition, further comprising the following steps: Step S100: selecting materials for the reaction tube body 15, the heat absorption layer 11, the heat storage layer 12, the isolation layer 13 and the heat uniforming layer 14 of the biomass gasification reaction tube 1 with reference to the biomass gasification reaction conditions; Step S200: Dimensions of the reaction tube body 15 , the heat absorption layer 11 , the heat storage layer 12 , the isolation layer 13 and the uniform heat layer 14 of the biomass gasification reaction tube 1 ; Step S300: determining the size of the heat collecting mirror 2 and each reaction tube support rod 3; Step S400: determining the arrangement of the heat collecting mirror 2 and the biomass gasification reaction tube 1; Step S500: Establishing a model and analyzing the reaction conditions of biomass gasification; Step S600: Design is completed.

[0058] In addition, in step S500, the method of establishing a model and analyzing the biomass gasification reaction conditions includes the following steps: Step S510: Establishing a finite element analysis model with reference to biomass gasification reaction conditions; Step S520: using Soltrace software to simulate and obtain a ray tracing diagram of the solar thermal collector; Step S530: using Comsol software to establish a heat transfer model of the solar thermal collector; Step S540: Analyze the heat transfer model.

[0059] In the above embodiment, it should be noted that the specific method of establishing the finite element analysis model with reference to the biomass gasification reaction conditions in step S510 is as follows: with reference to the biomass gasification reaction conditions, the design temperature in the reaction chamber is 550K, the design pressure is 1.5MPa, and the liner in the reaction chamber is made of Cu6.5Sn-0.1P high-strength alloy seamless steel pipe, based on the creep strength at high temperature, and the thickness is calculated according to the mid-diameter formula to be 20mm after rounding, and the finite element analysis model is established, and the edge effect is considered, and the mesh encryption at the edge ensures the solution accuracy. Figure 5 As shown, the stress of the reaction tube film is calculated using the fourth strength theory Mises stress to check the strength. The stress distribution is as follows Figure 6 As shown in Figure 2, further solution shows that the total creep strain within the design life is less than 1% of the maximum stress as the limit condition.

[0060] Here, it should be noted that the reaction chamber is the inner space of the reaction tube body 15 of the biomass gasification reaction tube 1 ; the inner space of the reaction chamber is the reaction tube body 15 .

[0061] The method of using Soltrace software to simulate and obtain the ray tracing diagram of the solar thermal collector in step S520 is as follows: Figure 7 As shown in FIG. 1 , the ray tracing diagram of the solar thermal collector at focal length obtained by simulating the Soltrace software, the light enters from a direction perpendicular to the opening plane, is reflected by the parabolic concentrator, and is focused on the reaction tube at the focal line. Here, the parabolic concentrator is the collector mirror 2.

[0062] Step S530: The method of using Comsol software to establish a heat transfer model of a solar thermal collector is to use Comsol software to establish a heat transfer model of a gasification reaction thermal collector and conduct a temperature field study. The thermal collector layer uses copper foam metal with a porosity of 50%, the phase change material uses paraffin with a phase change conversion temperature of 800K, and the solar radiation heat source is 800W / m 2 The reaction chamber is copper / water vapor convection heat exchange, and the temperature distribution of the collector in steady state is as follows Figure 8 As shown, it can be seen that after 400 seconds of stable light and heat radiation, the temperature of the reaction chamber reaches the biomass gasification reaction temperature, and the heat collection layer is the heat storage layer 12.

[0063] Study the temperature field of the gasification reaction bed and the pressure field from Fig. 9 , Fig.10 It can be seen that only in the inlet section 0-0.4m, the average temperature increases from 423K to 502K, with a temperature rise of 79K, and then the temperature rise slows down, and the average temperature increases from 502K to 532K in the 0.4m-4m range. The overall temperature rises by only 30K in the 3.5m long area; here, the reaction bed is the biomass gasification reaction tube 1.

[0064] The mechanism is that the reaction rate in the inlet area is low. As the temperature rises, the reaction rate gradually increases, the reaction endothermic heat increases, and most of the absorbed solar heat is used for gasification reaction endothermic heat, and only a small part is used to heat the synthesis gas, so the temperature change is small.

[0065] like Fig.11 At the outlet end of the reaction bed, the non-uniformity of the temperature distribution along the cross-sectional direction reaches the maximum, the highest temperature is 552K, the lowest temperature is 524K, and the maximum temperature difference is 28K. Here, the reaction bed is the biomass gasification reaction tube 1.

[0066] like Fig.12 The figure shows the pressure distribution of the catalytic bed reaction bed. The pressure of the gasification medium fluid gradually decreases along the tube. The outlet pressure is 0.1MPa. The inlet and outlet pressure difference is 0.0126MPa in the 4m long area. Here, the catalytic reaction bed is the biomass gasification reaction tube 1.

[0067] In the biomass gasification reaction tube 1, the biomass gasification product enters from the inlet, and by absorbing solar thermal energy, the biomass directly undergoes a gasification reaction and generates a synthesis gas containing carbon monoxide and hydrogen. Under typical working conditions, the concentration (amount of substance) of hydrogen and carbon monoxide is distributed as follows: Figure 2-13 As shown, in the biomass gasification reaction tube 1, similar to the temperature distribution, the concentration distribution of each substance also presents radial and axial non-uniformity.

[0068] The beneficial effects of the above optional embodiments are as follows: the design method of the solar thermal collector is based on the principle of enhanced heat transfer of porous media, constructs a porous metal / PCM phase change composite system, and designs a solar thermal collector for solar-driven biomass pyrolysis and gasification, which is used to drive solar biomass thermochemical reactions. According to the biomass thermochemical reaction conditions, the thickness of the tube wall in the reaction chamber, that is, the thickness of the tube wall of the reaction tube body 15, is designed, and the structural strength during high-temperature creep is verified by the finite element analysis method. The temperature field and pressure field of the device are studied by Comsol software simulation. The results show that the solar thermal energy can be evenly and stably transferred to the reaction chamber, that is, the inner space of the reaction tube body 15, through the high-temperature phase change heat storage and two uniform temperature heat transfer of the device, so as to ensure that the biomass pyrolysis and gasification reaction is carried out efficiently within a constant temperature range. The biomass thermochemical reaction carried out in the device is studied using AspenPlus software. The results show that the main gas components of the thermochemical reaction products carried out in this solar collector are: 60% CO+H2 (synthesis gas), as well as by-products % hydrocarbons and 30% CO2; this reveals the thermochemical reaction characteristics of biomass and indirectly solves the problems of insufficient heat collection temperature and uneven heat transfer in the traditional solar-driven biomass gasification reaction.

[0069] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A solar thermal collector, characterized in that: It comprises a biomass gasification reaction tube (1), a heat collecting mirror (2), a reaction tube support rod (3) and a base (8); The heat collecting mirror (2) is rotatably connected to the base (8), and the biomass gasification reaction tube (1) is connected to the heat collecting mirror (2) via a plurality of reaction tube support rods (3); The biomass gasification reaction tube (1) comprises a reaction tube body (15), a heat absorption layer (11) and a heat storage layer (12); the outer periphery of the reaction tube body (15) is coated with the heat storage layer (12); the outer periphery of the heat storage layer (12) is coated with the heat absorption layer (11); and one end of each reaction tube support rod (3) facing away from the heat collecting mirror (2) is connected to the heat absorption layer (11).

2. The solar thermal collector according to claim 1, characterized in that: The biomass gasification reaction tube (1) further comprises an isolation layer (13), wherein the isolation layer (13) is arranged between the reaction tube body (15) and the heat storage layer (12).

3. The solar thermal collector according to claim 2, characterized in that: The biomass gasification reaction tube (1) further comprises a uniform heating layer (14), wherein the uniform heating layer (14) is arranged between the reaction tube body (15) and the isolation layer (13).

4. The solar thermal collector according to claim 1, characterized in that: It also comprises a motor (10) and a mounting shell (81), wherein the mounting shell (81) is mounted in the middle of the base (8), the motor (10) is mounted in the mounting shell (81), and the output shaft of the motor (10) is connected to the heat collecting mirror (2).

5. The solar thermal collector according to claim 4, characterized in that: It also comprises a connecting seat (7), one side of the connecting seat (7) being connected to the heat collecting mirror (2), and the output shaft of the motor (10) being connected to the other side of the connecting seat (7).

6. The solar thermal collector according to claim 5, characterized in that: It also comprises a bottom plate (6), and the connecting seat (7) is connected to the heat collecting mirror (2) via the bottom plate (6).

7. The solar thermal collector according to claim 6, characterized in that: It also comprises a first clamping plate (4) and a second clamping plate (5), wherein a plurality of the first clamping plates (4) are arranged at intervals on the outer side of the heat collecting mirror (2), and a plurality of the second clamping plates (5) are arranged at intervals on the inner side wall of the heat collecting mirror (2), the bottom plate (6) is connected to the heat collecting mirror (2) via the plurality of the first clamping plates (4), and an end of each reaction tube support rod (3) facing away from the biomass gasification reaction tube (1) is connected to one of the second clamping plates (5).

8. The solar thermal collector according to any one of claims 1 to 7, characterized in that: It also comprises a pipe sleeve (9), and each of the reaction tube support rods (3) is connected to the biomass gasification reaction tube (1) via the pipe sleeve (9).

9. A method for designing a solar thermal collector, characterized in that: Using all the technical features of the solar thermal collector according to any one of claims 1 to 8, in addition, it also includes the following steps: Step S100: selecting materials for the reaction tube body (15), the heat absorption layer (11), the heat storage layer (12), the isolation layer (13) and the heat uniforming layer (14) of the biomass gasification reaction tube (1) with reference to the biomass gasification reaction conditions; Step S200: the dimensions of the reaction tube body (15), the heat absorption layer (11), the heat storage layer (12), the isolation layer (13) and the heat uniforming layer (14) of the biomass gasification reaction tube (1); Step S300: determining the dimensions of the heat collecting mirror (2) and each reaction tube support rod (3); Step S400: determining the arrangement of the heat collecting mirror (2) and the biomass gasification reaction tube (1); Step S500: Establishing a model and analyzing the reaction conditions of biomass gasification; Step S600: Design is completed.

10. The design method of a solar thermal collector according to claim 9, characterized in that: In step S500, the method of establishing a model and analyzing the biomass gasification reaction conditions includes the following steps: Step S510: Establishing a finite element analysis model with reference to biomass gasification reaction conditions; Step S520: using Soltrace software to simulate and obtain a ray tracing diagram of the solar thermal collector; Step S530: using Comsol software to establish a heat transfer model of the solar thermal collector; Step S540: Analyze the heat transfer model.

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