Solar-driven biomass pyrolysis-gasification energy utilization system running day and night

Abstract

The invention discloses a solar-driven biomass pyrolysis-gasification energy utilization system running day and night. The system comprises a biomass pyrolysis-gasification subsystem and a solar spectral photovoltaic water electrolysis subsystem. According to the system, solar frequency division heat collection, high-temperature synthesis gas sensible heat and ash residue waste heat are absorbed and stored in a gradient mode through molten salt and are used for providing heat needed by biomass pyrolysis reaction; in the daytime, the system provides heat required by high-temperature gasification reaction through solar full-spectrum light condensation, and the heat is provided by combustion of part of pyrolysis products when no light exists at night. According to the system, by integrating various energy utilization technologies such as solar full spectrum and spectral utilization, biomass gasification, photovoltaic power generation and waste heat utilization, coupling utilization of two renewable energy sources of solar energy and biomass energy and gradient utilization of energy are achieved, and the energy utilization efficiency of an energy system and the quality of synthesis gas are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of complementary utilization of various renewable energies, and particularly relates to a day-and-night operation solar-driven biomass pyrolysis-gasification energy utilization system. BACKGROUND

[0002] Coal, oil, natural gas and other fossil fuels have always dominated the global energy structure, greatly promoting the development of productivity, but their widespread use has also brought a series of problems such as air pollution, climate change, and harm to health, and fossil fuels are non-renewable energy, whose regeneration rate does not match the growing energy demand of today's society. Therefore, to achieve sustainable development, developing clean and efficient renewable energy has become the direction of future development.

[0003] The global energy structure transformation process is accelerating, and renewable clean energy such as solar energy and biomass has become the best choice to replace fossil fuels due to its efficiency, economic feasibility, and environmental friendliness. Biomass is internationally recognized as a zero-carbon renewable energy, which can be converted into syngas through gasification and then used as fuel or other products, which can better play its energy value. The biomass gasification process can be divided into pyrolysis and gasification reactions, and the temperature and heat required for pyrolysis are lower than those for gasification. In the traditional gasification process, the heat required for the reaction is provided by the combustion of biomass fuel itself, which consumes part of the biomass and produces by-products that hinder gasification, greatly reducing the effective utilization rate of biomass and the gasification efficiency.

[0004] Solar energy is the most abundant clean energy, with a global total of 301 times the capacity of existing coal-fired power plants, so large-scale conversion and storage of solar energy is an important technical route to achieve carbon neutrality. The solar spectrum range reaching the earth's surface is between 200-2500nm, including ultraviolet light, visible light and near-infrared light, which all carry a certain amount of energy, of which visible light and near-infrared light radiation accounts for the vast majority of energy, and different wavebands of solar energy can be converted into different grades of other energy. Solar photo-thermal utilization technology can convert full-spectrum and split-spectrum solar energy into heat energy, providing different levels of temperature and heat. Therefore, combining solar heat utilization technology with biomass gasification can use full-spectrum and split-spectrum solar energy to provide different levels of heat for the pyrolysis and gasification reactions of biomass gasification. In addition, the syngas produced by biomass gasification usually contains a large amount of high-temperature waste heat, and its recycling is an effective way to realize resource utilization.

[0005] Due to the intermittency of solar energy, solar energy cannot be provided at night, so it is necessary to couple traditional biomass gasification to realize continuous operation of biomass gasification, and using air as an oxidant will make the nitrogen content in the final synthesis gas too high, reducing the calorific value of the synthesis gas; using oxygen as an oxidant can largely solve this problem, but the cost of obtaining oxygen by traditional air separation technology is high. Electrolysis of water is an effective method to replace this high-cost technology, and solar photovoltaic power generation can convert solar energy into electrical energy to meet the electrical energy demand of water electrolysis. SUMMARY

[0006] The main purpose of the present application is to provide a day and night running solar energy driven biomass pyrolysis-gasification energy utilization system.

[0007] The present application utilizes a biomass pyrolysis-gasification subsystem composed of a heliostat field, a biomass gasifier, a molten salt cascade heat cycle path, a flue gas treatment device and other components to drive biomass thermochemical conversion; the system absorbs and stores solar energy, high-temperature synthesis gas sensible heat and ash residue waste heat through molten salt cascade absorption, and uses them to provide the heat required for biomass pyrolysis reaction; during the day, the system provides the heat required for high-temperature gasification through solar full-spectrum concentration, and when there is no light at night, it relies on partial pyrolysis product combustion to provide heat; a solar spectrum photovoltaic water electrolysis subsystem composed of photovoltaic panels, electrolytic cells, batteries and other components is used to drive the electrolysis of water through photovoltaic power generation, and to store other waveband energy in molten salt. The day and night running solar energy driven biomass pyrolysis-gasification energy utilization system established by the present application realizes the coupled utilization of solar energy and biomass energy and the cascade utilization of energy through solar full-spectrum and spectrum utilization, biomass gasification, photovoltaic power generation, waste heat recovery and other energy utilization technologies, which not only improves the stability and continuity of the biomass gasification system, but also solves the problem of solar intermittency, and increases the energy utilization efficiency of the energy system and the quality of the synthesis gas.

[0008] To achieve the above purpose, the technical scheme adopted by the present application is: The present application provides a day and night running solar energy driven biomass pyrolysis-gasification energy utilization system, which comprises a biomass pyrolysis-gasification subsystem and a solar spectrum photovoltaic water electrolysis subsystem. The biomass pyrolysis-gasification subsystem is driven by solar light concentration direct radiation and molten salt heat storage complementarily, which comprises a heliostat field, a biomass gasification furnace, a molten salt cascade heat circulation passage, a flue gas treatment device and a synthetic gas storage tank; the heliostat field collects full-spectrum sunlight and reflects it to the gasification reaction section for heating; the biomass gasification furnace is used for biomass thermochemical conversion, which comprises a pyrolysis reaction section, a gasification reaction section and an ash collection section from top to bottom; the molten salt cascade heat circulation passage circulates molten salt, which absorbs heat step by step and provides heat for the pyrolysis reaction section; the flue gas treatment device is used for removing impurities in the synthetic gas obtained from the gasification reaction section; the synthetic gas storage tank is used for storing synthetic gas. The solar spectrum-splitting photovoltaic water electrolysis subsystem comprises a photovoltaic panel, an electrolytic cell and a battery, the photovoltaic panel generates electricity by photovoltaic effect using light energy in the photovoltaic available wave band, and the remaining wave band light energy is used to heat molten salt in the molten salt cascade heat circulation passage; the electricity generated by photovoltaic effect enters the electrolytic cell to drive the electrolysis of water to generate O2 and H2, and the excess electricity is stored by the battery; the gas purification device performs purification treatment such as alkali removal and drying on O2 and H2; H2 enters the synthetic gas storage tank, and O2 is stored in an oxygen storage tank, and when the solar energy is insufficient, O2 is sent into the gasification reaction section and burns a part of pyrolysis products to provide the heat required for gasification reaction.

[0009] According to the preferred scheme of the present application, the pyrolysis reaction section of the biomass gasification furnace has a pyrolysis reaction cavity, the top of the pyrolysis reaction cavity is connected with a biomass feeding port, the pyrolysis reaction cavity is wrapped by a pyrolysis cavity molten salt jacket for heat transfer from molten salt to the pyrolysis reaction cavity, and the pyrolysis reaction cavity is connected with a gasification reaction cavity of the gasification reaction section through a downpipe passage; the gasification reaction cavity is connected with a water vapor inlet, an oxygen inlet and a synthetic gas outlet, one side of the gasification reaction cavity is provided with a light window allowing solar radiation to enter, and the outside of the light window is provided with a light window cover plate for shielding the light window; the bottom of the gasification reaction cavity is connected with an ash collection cavity of the ash collection section through a plurality of ash falling ports; the ash collection cavity is wrapped by an ash cavity molten salt jacket for heat transfer from high-temperature ash to molten salt.

[0010] According to the preferred scheme of the present application, the molten salt step heat cycle passage comprises a cold tank, a molten salt heat exchanger, an ash collection section of the biomass gasifier, a hot tank and a pyrolysis reaction section of the biomass gasifier connected in sequence by pipelines to form a cycle; a molten salt pump is arranged on the molten salt step heat cycle passage; the cold tank receives non-photovoltaic band light energy reflected by the photovoltaic panel to heat the molten salt, the molten salt in the cold tank is transferred to the molten salt heat exchanger to receive sensible heat of high-temperature synthesis gas, then the molten salt in the ash collection section of the ash cavity molten salt jacket receives high-temperature waste heat of the ash to become hot molten salt which enters the hot tank, that is, the energy of the hot molten salt in the hot tank comes from solar frequency collection, high-temperature synthesis gas sensible heat and ash waste heat; when heat is needed for pyrolysis reaction, the hot molten salt in the hot tank enters the pyrolysis cavity molten salt jacket to release heat, and the molten salt after heat release becomes cold molten salt which enters the cold tank to complete the molten salt heat cycle.

[0011] As the preferred scheme of the present application, the heliostat field is an array of full reflection heliostat concentrators, the surface is coated with an aluminum film and a silica protective layer, full spectrum utilization of solar energy is realized through light concentration reflection, and three-dimensional tracking of sunlight can be realized.

[0012] As the preferred scheme of the present application, the photovoltaic panel is composed of a light splitting plate, a photovoltaic cell panel and a photovoltaic panel support. The photovoltaic panel support is a hollow structure, and a circulating cooling water passage is formed in the inside of the photovoltaic panel support for cooling the photovoltaic cell panel; the light splitting plate is installed on the outer surface, and an interference type light splitting film is coated on the surface of the light splitting plate, the film is a SiO2 / TiO2 alternating stack structure, from top to bottom, it is 120nm of SiO2, 20nm of TiO2, 200nm of SiO2, 175nm of TiO2 and 195nm of SiO2, which is used for transmitting 400-1000nm band radiation and reflecting the rest band radiation; the photovoltaic cell panel is installed in the inside, and the material is polycrystalline silicon, which is used for photovoltaic power generation.

[0013] As the preferred scheme of the present application, the pyrolysis reaction cavity and the pyrolysis cavity molten salt jacket form a jacket type pyrolysis reaction device, which is a double-layer cavity structure, biomass flows in the inner cavity, and molten salt circulates in the outer circular cavity to realize continuous heating of the inner cavity; the ash collection cavity and the ash cavity molten salt jacket form a jacket type waste heat recovery device, which is a double-layer cavity structure, the inner cavity is filled with ash, and molten salt circulates in the outer circular cavity to realize continuous recovery of high-temperature ash waste heat. The outer wall of the two devices is wrapped with refractory bricks to prevent heat loss of the molten salt.

[0014] As the preferred scheme of the present application, the medium in the molten salt heat exchanger and the cold tank / hot tank is NaNO3-KNO3 molten salt.

[0015] As a preferred scheme of the present application, the flue gas treatment device is composed of a bag filter, a tar condenser, a gas scrubber, an adsorption box and a drying machine.

[0016] As a preferred scheme of the present application, a copper-based or iron-based catalyst is placed in the water gas shift device.

[0017] As a preferred scheme of the present application, the electrolytic cell is a KOH alkaline water electrolytic cell, and the battery is a lithium iron phosphate battery.

[0018] As a preferred scheme of the present application, the biomass gasification furnace is a staged gasification furnace, which is composed of a pyrolysis reaction section, a gasification reaction section and an ash collection section, and has three heating modes of molten salt heating, solar light concentration heating and pyrolysis product combustion, and can automatically and real-timely adjust according to the actual situation of the temperature and heat in the reaction furnace.

[0019] The present application also provides a solar-driven biomass pyrolysis-gasification energy utilization method based on the above-mentioned system, which automatically and real-timely adjusts and switches the three heating modes of the biomass gasification furnace by monitoring the local time, the solar radiation intensity, the pyrolysis reaction cavity temperature, the gasification reaction cavity temperature and the CO / H2 ratio in the synthesis gas. The system predicts the solar radiation period in advance according to the local day and night duration, and real-timely collects the local time and the solar radiation intensity, opens the light window cover plate and starts the solar light concentration heating mode to heat the gasification reaction cavity when the time is in the set solar radiation period, and adjusts the light concentration mirror angle to stabilize the gasification reaction cavity temperature in the range of 1000-1300 DEG C. 2 If the solar radiation intensity is lower than 400-500 W / m2, the gasification reaction cavity temperature cannot be stabilized in the set range by solar radiation, which indicates that the solar light concentration radiation cannot meet the heat demand of the gasification reaction, and then the O2 flow is increased to adjust the gasification reaction cavity temperature by partial pyrolysis product combustion. The synthesis gas generated by the gasification reaction is real-timely detected by the online gas analysis device, the biomass and water vapor feeding rate and mass ratio are adjusted to stabilize the H2 / CO molar ratio in the set range of 1.5-2.0. If the time is not in the solar radiation period, the light window cover plate is closed, the pyrolysis product combustion heating mode is switched to drive the biomass gasification, and the O2 flow is real-timely adjusted to stabilize the gasification reaction cavity temperature in the set range. The pyrolysis reaction cavity temperature is always adjusted by the molten salt flow to stabilize the reaction cavity temperature in the range of 400-500 DEG C. The system predicts the dynamic change trend of the solar radiation, temperature and synthesis gas composition, adjusts the execution parameters in advance to reduce the adjustment lag and improve the system stability.

[0020] From the above technical scheme, the main innovation of the present application is that: (1) Cascade utilization of solar full spectrum and split spectrum: The biomass gasification reaction is driven by the solar full spectrum concentrated radiation reflected by the heliostat field. The photovoltaic panel with split plate is used to realize solar frequency power generation and frequency heat collection, realize the split utilization of solar energy and improve the utilization efficiency of solar energy.

[0021] (2) Biomass graded gasification: The biomass gasification process is spatially divided into an upper pyrolysis section and a lower gasification section. The pyrolysis reaction of biomass is driven by a medium-low temperature heat source to produce volatiles and coke, while the gasification reaction of biomass is driven by a high temperature heat source to produce syngas and ash residue, thereby realizing the spatial separation of the two-stage reaction and the graded utilization of energy.

[0022] (3) Continuous day and night biomass pyrolysis and gasification driven by multiple heat sources: During the day when there is sufficient sunlight, the system provides the energy required for biomass gasification by focusing and reflecting full-spectrum solar radiation through a heliostat field. It also provides the energy required for biomass pyrolysis by absorbing and storing solar energy at different frequencies, sensible heat from high-temperature syngas, and waste heat from ash residue through a cascaded absorption of molten salt. At night when there is no sunlight, the biomass pyrolysis reaction is continuously driven by molten salt heat storage, and the biomass gasification reaction is driven by the combustion of some pyrolysis products, ensuring the stability of the biomass gasifier's nighttime operation. By monitoring key parameters such as solar radiation intensity, pyrolysis reaction chamber temperature, and gasification reaction chamber temperature, the system automatically adjusts and switches the three heating modes of the biomass gasifier to ensure continuous system operation.

[0023] (4) Solar energy and biomass complementarity and synergy: The system uses solar energy and biomass as two renewable energy sources to construct a complementary and coupled operation mode, fully coupling the high concentrated energy density and efficient thermochemical driving capability of solar energy and the stable heat energy supply and flexible and adjustable process of biomass. This solves the problems of intermittency of solar energy and unstable heat supply of biomass gasification, and realizes the efficient storage of solar energy into chemical energy form and the resource utilization of biomass.

[0024] (5) Coupling of solar photovoltaic power generation with water electrolysis for hydrogen / oxygen production: The electrical energy generated by the photovoltaic panel frequency division power generation is used to drive the water electrolysis reaction to generate O2 and H2, which are used for the combustion of pyrolysis products and the regulation of the H2 ratio in the syngas, respectively; when the stored O2 is insufficient, the stored electrical energy is used to continue water electrolysis to make up for the required O2. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a solar-driven biomass pyrolysis-gasification energy utilization system that operates day and night.

[0026] Figure 2 This is a schematic diagram of the structure of a biomass gasification furnace.

[0027] Figure 3 This is a schematic diagram of the structure of a photovoltaic panel.

[0028] Figure 4 is a flow chart of a solar energy driven biomass pyrolysis-gasification energy utilization method.

[0029] In the figure: 1 is a heliostat field, 2 is a biomass gasifier, 3 is a molten salt heat exchanger, 4 is a cold tank, 5 is a hot tank, 6 is a flue gas treatment device, 7 is a syngas storage tank, 8 is a photovoltaic panel, 9 is an electrolytic cell, 10 is a battery, 11 is a gas purification device, 12 is an oxygen storage tank, 13 is a biomass feeding port, 14 is a pyrolysis reaction cavity, 15 is a pyrolysis cavity molten salt jacket, 16 is a molten salt upper inlet, 17 is a molten salt upper outlet, 18 is a drop tube passage, 19 is a light window, 20 is a gasification reaction cavity, 21 is a water vapor inlet, 22 is an oxygen inlet, 23 is a syngas outlet, 24 is an ash outlet, 25 is an ash collection cavity, 26 is an ash cavity molten salt jacket, 27 is a molten salt lower inlet, 28 is a molten salt lower outlet, 29 is a light window cover plate, 30 is a light splitting plate, 31 is a photovoltaic cell panel, and 32 is a photovoltaic panel support. DETAILED DESCRIPTION

[0030] The structural principles and working principles of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0031] Figure 1 is a structural schematic diagram of a solar energy driven biomass pyrolysis-gasification energy utilization system running day and night provided by the present application. The system comprises a biomass pyrolysis-gasification subsystem and a solar spectrum splitting photovoltaic water electrolysis subsystem.

[0032] When the sunlight is sufficient in the daytime, the sunlight is respectively irradiated to the total reflection condenser of the heliostat field 1 and the photovoltaic panel 8, the total reflection condenser collects the sunlight, improves the energy density of the solar radiation, and directly radiates the solar radiation to the gasification reaction section of the biomass gasification furnace 2; the photovoltaic panel 8 realizes the frequency division of the sunlight spectrum through the light splitting plate 30, wherein the waveband light energy that can be used by the photovoltaic panel is transmitted to the photovoltaic cell panel 31 below to generate electricity, and the rest of the waveband light energy is reflected to the cold tank 4 to heat the molten salt. The biomass raw material is added from the top of the biomass gasification furnace 2, and the steam is introduced from the side, the hot molten salt from the hot tank 5 enters the biomass gasification furnace 2 to drive the biomass pyrolysis reaction, and the heat-released molten salt then enters the cold tank 4. The full-spectrum high-temperature concentrated solar energy reflected by the total reflection condenser drives the biomass gasification reaction, and the high-temperature synthesis gas generated by the biomass gasification furnace 2 enters the molten salt heat exchanger 3. The molten salt in the cold tank 4 absorbs the solar energy frequency division heat collection in the cold tank 4, and then enters the molten salt heat exchanger 3 to absorb the sensible heat of the high-temperature synthesis gas, and then enters the biomass gasification furnace 2 to absorb the residual heat of the ash residue, and is stored in the hot tank 5 after the above-mentioned cascade heat absorption. The synthesis gas after heat exchange in the molten salt heat exchanger 3 is treated by the flue gas treatment device 6 to remove impurities such as tar, particulate matter and acid gas in the synthesis gas, and finally enters the synthesis gas storage tank 7.

[0033] The electric energy generated by the frequency division of the photovoltaic panel 8 enters the electrolytic cell 9 to drive the electrolysis of water to generate O2 and H2, and the O2 and H2 enter the gas purification device 11 for alkali removal, drying and other gas purification treatments, and finally the O2 is stored in the oxygen storage tank 12, and the H2 enters the synthesis gas storage tank 7 to be stored together with the gasification synthesis gas, thereby increasing the proportion of H2 in the synthesis gas, and the excess electric energy generated by the frequency division is stored in the storage battery 10.

[0034] When there is no light at night, the biomass pyrolysis reaction continues to be driven by the heat storage of the molten salt, but the biomass gasification reaction cannot be driven by the sunlight, at this time, the conventional biomass gasification reaction is adopted, that is, a part of the pyrolysis products is combusted to provide the heat required for the gasification reaction, at this time, the flow of O2 introduced into the biomass gasification furnace 2 is increased, and the heat released by combusting a part of the pyrolysis products is used to drive the biomass gasification reaction; when the O2 is insufficient, the electrolysis of water is driven by the electric energy stored in the storage battery 10 to supplement the required O2, so that the system can be continuously operated day and night.

[0035] The system contains molten salt cascade heat cycle passage for realizing cascade recovery and utilization of heat. Cold tank 4 stores cold molten salt, which receives solar frequency collection from photovoltaic panel 8, and under the action of molten salt pump, the molten salt receives high-temperature synthesis gas sensible heat in molten salt heat exchanger 3, and then enters ash cavity molten salt jacket 26 at the lower part of biomass gasifier 2 to receive high-temperature waste heat of ash, and becomes hot molten salt into hot tank 5, that is, the energy of hot molten salt in hot tank 5 comes from solar frequency collection, high-temperature synthesis gas sensible heat and ash waste heat. When heat is needed for pyrolysis reaction, hot molten salt in hot tank 5 will enter pyrolysis cavity molten salt jacket 15 at the upper part of biomass gasifier 2 under the action of molten salt pump, and the molten salt after releasing heat becomes cold molten salt into cold tank 4, completing the heat cycle of molten salt.

[0036] Figure 2 The present application provides a structure diagram of a biomass gasifier. The gasifier is a staged gasification reactor, and the internal main body is composed of a pyrolysis reaction section located at the upper part, a gasification reaction section located at the middle and lower part, and an ash collection section located at the bottom.

[0037] Biomass feed inlet 13 is installed outside the upper cover plate of the furnace body, and steam inlet 21 and oxygen inlet 22 are installed at the middle of the side of the furnace body. In addition, adjusting devices are arranged at the biomass feed inlet and the gas inlet for adjusting key parameters such as flow rate.

[0038] The pyrolysis reaction section is composed of pyrolysis reaction cavity 14, pyrolysis cavity molten salt jacket 15, upper molten salt inlet 16 and upper molten salt outlet 17. Pyrolysis reaction cavity 14 is located between the upper cover plate at the upper part of the furnace body and drop tube passage 18, and the internal pyrolysis reaction cavity 14 performs biomass pyrolysis reaction. Pyrolysis reaction cavity 14 is wrapped by pyrolysis cavity molten salt jacket 15 to form a jacketed pyrolysis reaction device, and the left side of pyrolysis cavity molten salt jacket 15 is provided with upper molten salt inlet 16 connected with hot tank 5, and the right side is provided with upper molten salt outlet 17 connected with cold tank 4, and high-temperature molten salt from hot tank 5 enters pyrolysis cavity molten salt jacket 15 to provide heat for pyrolysis reaction. The pyrolysis reaction section is connected with the gasification reaction section through drop tube passage 18.

[0039] The gasification reaction section is composed of light window 19, gasification reaction cavity 20, synthesis gas outlet 23 and light window cover plate 29. The left side of gasification reaction cavity 20 is provided with light window 19 allowing solar radiation (full-spectrum high-temperature concentrated solar energy reflected by full-reflection concentrator) to enter, and the right side is provided with synthesis gas outlet 23 connected with molten salt heat exchanger 3, and the outside of light window 19 is provided with light window cover plate 29. The bottom of gasification reaction cavity 20 is connected with ash collection section through ash drop opening 24. The gasification reaction section receives pyrolysis products from the pyrolysis reaction section, and converts the pyrolysis products into synthesis gas in the gasification reaction section.

[0040] The ash collection section is provided with an ash collection cavity 25, an ash cavity molten salt jacket 26, a molten salt lower inlet 27 and a molten salt lower outlet 28. The ash collection cavity 25 is wrapped by the ash cavity molten salt jacket 26 to form a jacketed waste heat recovery device. The ash cavity molten salt jacket 26 is provided with the molten salt lower inlet 27 connected with the molten salt heat exchanger 3 on the right side, and the molten salt lower outlet 28 connected with the hot tank 5 on the left side. The molten salt from the molten salt heat exchanger 3 absorbs heat in the ash cavity molten salt jacket 26 and enters the hot tank 5.

[0041] The biomass gasifier 2 provided by the application has two working modes of day and night, and three heating modes of solar light concentration heating, molten salt heating and pyrolysis product combustion, and specifically as follows: The biomass enters the pyrolysis reaction cavity 14 under the action of gravity. The hot molten salt in the hot tank 5 enters the pyrolysis cavity molten salt jacket 15 through the molten salt upper inlet 16 under the action of the molten salt pump, and transmits heat to the inside of the pyrolysis reaction cavity 14 through the wall surface of the pyrolysis reaction cavity 14 to raise the temperature inside the pyrolysis reaction cavity 14 to the reaction temperature. The cold molten salt after heat exchange is discharged through the molten salt upper outlet 17, and then the hot molten salt enters the pyrolysis cavity molten salt jacket 15 from the hot tank 5 under the action of the molten salt pump to realize the circulation heating of the molten salt in the two working conditions of day and night. The pyrolysis reaction of biomass occurs in the pyrolysis reaction cavity 14 under the continuous heating action of the pyrolysis cavity molten salt jacket 15, and the pyrolysis products enter the gasification reaction cavity 20 through the downpipe channel 18.

[0042] The water vapor enters the gasification reaction cavity 20 through the water vapor inlet 21. When the light is sufficient, the concentrated solar energy reflected and gathered by the heliostat field 1 enters the gasification reaction cavity 20 through the light window 19 to directly radiate the pyrolysis products and cause the gasification reaction. The gasification synthesis gas enters the molten salt heat exchanger 3 through the synthesis gas outlet 23 to recover and utilize the high-temperature waste heat in the synthesis gas. The residual ash enters the ash collection cavity 25 through the ash drop opening 24, and the molten salt enters the ash cavity molten salt jacket 26 through the molten salt lower inlet 27. The high-temperature waste heat in the ash penetrates through the wall surface into the molten salt to become hot molten salt which enters the hot tank 5 through the molten salt lower outlet 28. When there is no light at night, the light window cover plate 29 is closed to prevent the loss of heat in the furnace. At this time, the O2 flow is increased, and the concentrated heating gasification mode is switched to the traditional heating gasification mode, that is, the heat required for the gasification reaction is provided by burning part of the pyrolysis products.

[0043] Figure 3The figure is a schematic diagram of a photovoltaic panel structure provided by the present application. The photovoltaic panel 8 is composed of a light splitting plate 30, a photovoltaic cell panel 31 and a photovoltaic panel support 32. The photovoltaic panel support 32 is a hollow structure, and a circulating water passage is formed inside the photovoltaic panel support 32. The circulating water in the circulating water passage is used to take away the heat of the photovoltaic cell panel 31. The light splitting plate 30 is installed on the outer surface of the photovoltaic panel 8, and an interference type light splitting film is coated on the surface of the light splitting plate 30. The film is a SiO2 / TiO2 alternating stack structure. In the embodiment, from top to bottom, it is 120nm of SiO2, 20nm of TiO2, 200nm of SiO2, 175nm of TiO2 and 195nm of SiO2. The film can transmit the radiation of the 400-1000nm wave band and reflect the radiation of the remaining wave band. The photovoltaic cell panel 31 is installed inside the photovoltaic panel 8, and the material is polycrystalline silicon. When the sunlight is radiated to the surface of the light splitting plate 30, the sunlight of the 400-1000nm wave band is transmitted through the light splitting plate 30 and is incident on the surface of the photovoltaic cell panel 31, so as to convert the solar energy into electric energy, realize frequency division power generation, and reflect the sunlight of the remaining wave band into the cold tank 4, so as to transfer the heat to the molten salt and realize light splitting heat collection. In the process, the circulating cooling water is introduced into the photovoltaic panel support 32, so as to ensure the normal operation of the photovoltaic cell panel 31.

[0044] Figure 4 The figure is a flow chart of a solar driven biomass pyrolysis-gasification energy utilization method provided by the present application. The system automatically adjusts and switches three heating modes of the biomass gasifier 2 in real time by monitoring the local time, the solar radiation intensity, the pyrolysis reaction cavity temperature, the gasification reaction cavity temperature and the CO / H2 ratio in the synthesis gas. The system predicts the solar radiation period in advance according to the local day-night duration, and collects the local time and the solar radiation intensity in real time. When the time is located in the set solar radiation period, the light window cover plate 29 is opened, the solar concentrating heating mode is started, and the gasification reaction cavity 20 is heated. The angle of the concentrator is dynamically adjusted, so that the gasification reaction cavity temperature is stabilized in the range of 1000-1300℃. If the solar radiation intensity is lower than 400-500W / m2, the electric heating mode is started. If the solar radiation intensity is higher than 400-500W / m2, the gasification reaction cavity 20 is heated by the solar radiation. The system can automatically adjust the heating mode according to the solar radiation intensity, so as to realize the automatic adjustment of the heating mode. 2Or by solar radiation can not realize gasification reaction cavity temperature stability in the set range, show that at this time solar concentration radiation has been unable to meet the gasification reaction heat demand, then increase the O2 flow into the biomass gasification furnace 2, by burning part of the pyrolysis products to adjust the gasification reaction cavity temperature. Through the online gas analysis device for real-time detection of the synthesis gas generated by the reaction, adjust the biomass and steam feed rate and mass ratio, so that the H2 / CO molar ratio is stable in the set range of 1.5~2.0. If the time is not in the receiving solar radiation period, the controller closes the light window cover plate 29, switches to the pyrolysis product combustion heating mode (exothermic reaction of carbon and combustible gas and oxygen) to drive the biomass gasification, and adjusts the O2 flow in real time to make the gasification reaction cavity temperature stable in the set range. The pyrolysis reaction cavity temperature is always adjusted by the molten salt flow, so that the pyrolysis reaction cavity temperature is stable in the range of 400~500℃. The system predicts the dynamic change trend of solar radiation, temperature and synthesis gas composition, adjusts the execution parameters in advance, reduces the adjustment lag, and improves the system stability.

[0045] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A solar-powered biomass pyrolysis-gasification energy utilization system that operates day and night, characterized in that, This includes a biomass pyrolysis-gasification subsystem and a solar-powered multispectral photovoltaic water electrolysis subsystem; The biomass pyrolysis-gasification subsystem is driven by a combination of direct solar radiation and molten salt thermal storage, and includes: a heliostat field (1), a biomass gasifier (2), a molten salt cascade thermal circulation path, a flue gas treatment device (6), and a syngas storage tank (7); the heliostat field (1) gathers full-spectrum sunlight and reflects it to the gasification reaction section of the biomass gasifier (2) for heating; the biomass gasifier (2) is used for the thermochemical conversion of biomass, and it includes a pyrolysis reaction section, a gasification reaction section, and an ash collection section from top to bottom; molten salt circulates in the molten salt cascade thermal circulation path, and the molten salt absorbs heat step by step to heat the pyrolysis reaction section; the flue gas treatment device (6) is used to remove impurities in the syngas obtained in the biomass gasifier (2); the syngas storage tank (7) is used to store syngas; The solar-powered photovoltaic electrolysis water subsystem includes a photovoltaic panel (8), an electrolytic cell (9), a storage battery (10), a gas purification device (11), and an oxygen storage tank (12). The photovoltaic panel (8) uses the available wavelength of the photovoltaic array to generate photovoltaic power, and the remaining wavelength of the photovoltaic array is used to heat the molten salt in the molten salt cascade thermal circulation path. The electrical energy generated by the photovoltaic power generation enters the electrolytic cell (9) to drive the electrolysis of water to generate O2 and H2. The excess electrical energy is stored by the storage battery (10). The gas purification device (11) is used for purification treatment such as alkali removal and drying of O2 and H2. H2 enters the synthesis gas storage tank (7), and O2 is stored in the oxygen storage tank (12). When solar energy is insufficient, O2 is sent to the gasification reaction section and some pyrolysis products are burned to provide the heat required for the gasification reaction.

2. The solar-driven biomass pyrolysis-gasification energy utilization system operating day and night according to claim 1, characterized in that, The pyrolysis reaction section of the biomass gasifier (2) has a pyrolysis reaction chamber (14), the top of which is connected to the biomass feed inlet (13). The pyrolysis reaction chamber (14) is wrapped by a molten salt jacket (15) to transfer the heat of the molten salt to the pyrolysis reaction chamber (14). The pyrolysis reaction chamber is connected to the gasification reaction chamber of the gasification reaction section through a drop pipe channel (18). The gasification reaction chamber (20) is connected to a steam inlet (21), an oxygen inlet (22), and a syngas outlet (23). A light window (19) that allows solar radiation to enter is provided on one side of the gasification reaction chamber (20). A light window cover plate (29) is provided on the outside of the light window (19) to block the light window (19). The bottom of the gasification reaction chamber is connected to the ash collection chamber (25) of the ash collection section through multiple ash drop outlets (24). The ash collection chamber (25) is wrapped by the molten salt jacket (26) of the ash chamber, which is used to transfer the residual heat of the high-temperature ash to the molten salt.

3. The solar-driven biomass pyrolysis-gasification energy utilization system operating day and night according to claim 1, characterized in that, The heliostat field (1) is an array of total reflection heliostat concentrators with an aluminum film and a silicon dioxide protective layer on the surface. It realizes the full spectrum utilization of solar energy through light concentration and reflection, improves the energy density of solar radiation, and directly radiates it to the gasification reaction section of the biomass gasifier.

4. The solar-driven biomass pyrolysis-gasification energy utilization system operating day and night according to claim 1, characterized in that, The photovoltaic panel (8) consists of a beam splitter (30), a photovoltaic cell panel (31), and a photovoltaic panel support (32); the photovoltaic panel support (32) has a hollow structure, and its interior forms a circulating cooling water passage for cooling the photovoltaic cell panel (31); The beam splitter (30) is installed on the outer surface, and its surface is coated with an interference-type beam splitting film, which can transmit radiation in the 400-1000nm band and reflect radiation in other bands; the photovoltaic cell panel (31) is installed below the beam splitter (30), and it receives the transmitted photovoltaic usable band radiation to generate photovoltaic power; the heat generated by the solar frequency division heat collection is transferred to the cold tank (4) of the molten salt cascade heat circulation path.

5. The solar-driven biomass pyrolysis-gasification energy utilization system operating day and night according to claim 1, characterized in that, The pyrolysis reaction chamber (14) and the molten salt jacket (15) of the pyrolysis chamber form a jacketed pyrolysis reaction device. This device has a double-layer cavity structure. Biomass flows in the inner cavity, and molten salt circulates in the outer ring cavity to achieve continuous heating of the inner cavity. The ash collection chamber (25) and the molten salt jacket (26) of the ash chamber form a jacketed waste heat recovery device. This device has a double-layer cavity structure. The inner cavity contains ash, and molten salt circulates in the outer ring cavity to achieve continuous recovery of waste heat from high-temperature ash.

6. The solar-driven biomass pyrolysis-gasification energy utilization system operating day and night according to claim 2, characterized in that, The molten salt cascade thermal circulation path includes a cold tank (4), a molten salt heat exchanger (3), an ash collection section of the biomass gasifier (2), a hot tank (5), and a pyrolysis reaction section of the biomass gasifier (2) connected sequentially by pipelines to form a circulation; a molten salt pump is installed on the molten salt cascade thermal circulation path; wherein, the cold tank (4) receives non-photovoltaic band light energy reflected by the photovoltaic panel to heat the molten salt, and the molten salt in the cold tank (4) is transferred to the molten salt heat exchanger (3) to receive high-temperature syngas. The hot salt then enters the ash chamber molten salt jacket (26) of the ash collection section to receive the high-temperature residual heat of the ash, and becomes hot molten salt that enters the hot tank (5). That is, the energy of the hot molten salt in the hot tank (5) comes from solar frequency collection, high-temperature syngas sensible heat and ash residual heat respectively. When the pyrolysis reaction requires heat, the hot molten salt in the hot tank (5) will enter the molten salt jacket (15) of the pyrolysis chamber. After releasing heat, the molten salt becomes cold molten salt again and enters the cold tank (4) to complete the molten salt thermal cycle.

7. The solar-driven biomass pyrolysis-gasification energy utilization system operating day and night according to claim 2, characterized in that, The biomass gasifier (2) has three heating methods: solar concentrating heating, molten salt heating, and pyrolysis product combustion; During the day when there is sufficient sunlight, the biomass undergoes pyrolysis in the pyrolysis reaction chamber (14) through the continuous heating effect of the molten salt jacket (15) of the pyrolysis chamber. The pyrolysis products enter the gasification reaction chamber (20) through the drop pipe channel (18). The full-spectrum concentrated solar energy reflected and gathered by the heliostat field (1) enters the gasification reaction chamber (20) through the light window (19) and directly radiates the pyrolysis products, causing a gasification reaction. The syngas enters the molten salt heat exchanger (3), and the residual ash enters the ash collection chamber (25). The molten salt jacket (26) of the ash chamber continuously recovers the high-temperature waste heat in the ash. When there is no light at night, the light window cover (29) is closed to prevent heat loss from the furnace. The pyrolysis reaction continues to be driven by the molten salt heating in the molten salt ladder thermal circulation path. At this time, the O2 flow rate into the gasification reaction chamber (20) is increased, and the concentrated light heating gasification mode is switched to the pyrolysis product heating gasification mode which provides the heat required for the gasification reaction by burning part of the pyrolysis products. When O2 is insufficient, the electrical energy in the battery (10) is used to drive the electrolysis of water reaction to supplement the required O2, so as to realize the continuous operation of the system day and night.

8. A solar-driven biomass pyrolysis-gasification energy utilization method according to claim 7, characterized in that, The system monitors the local time, solar radiation intensity, pyrolysis reaction chamber temperature, gasification reaction chamber temperature, and CO / H2 ratio in the syngas in the area where the system is located in real time. Based on the monitoring structure, the heating mode of the biomass gasifier (2) is adjusted and switched in real time. The system predicts the solar radiation period in advance based on the local day and night duration, and collects the local time and solar radiation intensity in real time. When the current time is within the set solar radiation period, the light window cover (29) is opened, the solar concentrating heating mode is turned on, the gasification reaction chamber (20) is heated, and the temperature of the gasification reaction chamber is kept stable in the range of 1000~1300℃ by dynamically adjusting the angle of the concentrating mirror. If the solar radiation intensity is below 400~500W / m 2 If the temperature of the gasification reaction chamber cannot be stabilized within the set range by solar radiation, it indicates that the concentrated solar radiation is no longer sufficient to meet the heat requirements of the gasification reaction. In this case, the O2 flow rate is increased, and the temperature of the gasification reaction chamber is regulated by the combustion of some pyrolysis products. The syngas generated by the gasification reaction is monitored in real time by an online gas analysis device, and the feed rate and mass ratio of biomass and water vapor are adjusted to stabilize the H2 / CO molar ratio within the set range of 1.5 to 2.

0. If the time is not during the solar radiation period, close the light window cover (29), switch to the pyrolysis product combustion heating mode to drive biomass gasification, and stabilize the temperature of the gasification reaction chamber within the set range by adjusting the O2 flow rate in real time. The temperature of the pyrolysis reaction chamber is always kept stable within the range of 400~500℃ by adjusting the molten salt flow rate.

9. The method according to claim 8, characterized in that, The system predicts the dynamic changes in solar radiation, temperature, and syngas composition, and adjusts various execution parameters in advance to reduce adjustment lag and improve system stability.

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