A solar energy coupled biomass gasification and chemical looping combustion SOFC combined cooling heating and power system

Abstract

The application discloses a solar energy coupled biomass gasification and chemical chain combustion SOFC combined cooling, heat and power system in the technical field of distributed energy, which comprises a solar energy assisted biomass gasification subsystem, an SOFC power generation subsystem, a supercritical carbon dioxide power cycle subsystem, a chemical chain combustion subsystem and a refrigeration and heat supply subsystem; the system collects solar energy, and the gasification agent, biomass and the gasification agent are reacted to generate synthetic gas for the SOFC power generation subsystem to generate power; the SOFC anode tail gas enters the chemical chain combustion subsystem to perform flameless oxidation and release heat, the high-grade heat released drives the supercritical carbon dioxide power cycle subsystem to perform cascade power generation, and the remaining low-grade waste heat is recycled by the refrigeration and heat supply subsystem to realize the collaborative output of cold, heat and power. The application improves the comprehensive energy efficiency of the system through multi-energy complementation and energy cascade utilization, and realizes carbon dioxide enrichment in the chemical chain combustion subsystem.

Description

Technical Field

[0001] This invention relates to the field of distributed energy and multi-energy complementarity technology, and in particular to a SOFC combined cooling, heating and power system that couples solar energy with biomass gasification and chemical looping combustion. Background Technology

[0002] With the increasing demand for distributed energy, the need for efficient and stable combined cooling, heating, and power (CCHP) systems is growing in scenarios such as industrial parks and building complexes. Solar energy is intermittent and fluctuates, and while biomass is renewable and can be stored, its direct combustion has limited energy efficiency and is difficult to control emissions. Therefore, CCHP based on biomass gasification syngas has attracted attention.

[0003] In existing biomass gasification processes, gasifying agents such as water / steam are typically introduced to regulate the reaction and syngas composition. However, when the gasifying agent temperature is too low, it can easily lead to increased heat demand, fluctuations in syngas quality, and a decrease in partial load efficiency. Therefore, electric heating or supplementary combustion is often required to raise the temperature, increasing energy consumption and carbon emissions. At the same time, solar thermal utilization is often insufficiently coupled with the gasifying agent preheating process, making it difficult to achieve efficient utilization within the system.

[0004] Furthermore, the anode exhaust gas of solid oxide fuel cells typically undergoes oxidation and heat release via an afterburner or catalytic burner. This type of afterburner heat release process lacks controllability and temperature matching, making it difficult to achieve efficient cascade utilization with downstream power cycles and waste heat recovery units, thus affecting the stability and overall efficiency of the combined heat and power (CHP) output. In summary, there is an urgent need for a CHP system that can utilize solar energy to preheat the gasifying agent and replace the fuel cell afterburner with a controllable heat release unit, thereby improving heat source matching and cascade utilization. Summary of the Invention

[0005] The purpose of this invention is to provide a solar-coupled SOFC (Solar-Powered Fuel Cell) system that combines solar energy with biomass gasification and chemical looping combustion. By heating the gasification agent with solar energy and replacing the afterburner of the fuel cell with chemical looping combustion and coupling it with a supercritical carbon dioxide power cycle, the system achieves graded utilization of the heat source and combined cooling, heating and power output, thereby improving the overall energy efficiency and operational stability of the system.

[0006] To achieve the above objectives, this invention employs the following technical solution: a solar-coupled SOFC (Solar-Powered Fuel Cell) system combining biomass gasification and chemical looping combustion, comprising a solar-assisted biomass gasification subsystem, a solid oxide fuel cell power generation system, a supercritical carbon dioxide power cycle subsystem, a chemical looping combustion subsystem, and a refrigeration and heating subsystem; the solar-assisted biomass gasification subsystem utilizes solar energy to react a gasifying agent, biomass, and the gasifying agent to generate syngas, which is then supplied to the solid oxide fuel cell power generation system for electricity generation; the anode exhaust gas generated by the solid oxide fuel cell power generation system enters the chemical looping combustion subsystem for flameless oxidation, and the released high-temperature heat drives the supercritical carbon dioxide power cycle subsystem for cascaded power generation, while the discharged medium- and low-temperature waste heat supplies the refrigeration and heating subsystem for cooling and heating, ultimately achieving gas-liquid separation and carbon dioxide enrichment.

[0007] The above subsystems are connected by pipelines and valves to form an energy cascade utilization loop.

[0008] As a further improvement to the technical solution of this invention, the solar-assisted biomass gasification subsystem includes a water pump, a heat exchanger, a parabolic trough solar collector, a distributor, a biomass dryer, a biomass pyrolysis furnace, a biomass gasification furnace, and a gas-solid separator. The water pump inlet is connected to an external water source, and its outlet is connected to the heat exchanger inlet. The heat exchanger outlet is connected to the parabolic trough solar collector inlet, and the parabolic trough solar collector outlet is connected to the distributor inlet. The distributor outlet is divided into two paths via pipelines, one path connected to the gasifying agent inlet of the biomass gasification furnace, and the other path connected to the steam inlet of the biomass pyrolysis furnace. The biomass outlet of the biomass dryer is connected to the feed inlet of the biomass pyrolysis furnace, and the product flow outlet of the biomass pyrolysis furnace is connected to the feed inlet of the biomass gasification furnace. The biomass gasification furnace outlet is connected to the gas-solid separator inlet. The gas phase outlet of the gas-solid separator is connected to the anode inlet of the solid oxide fuel cell stack in the solid oxide fuel cell power generation system.

[0009] 1) Solar energy-gasifying agent heating and syngas generation chain: External water source enters the parabolic trough solar collector for heating after passing through a water pump and heat exchanger, and is divided into two paths by a splitter, which are respectively connected to the gasifying agent inlet of the biomass gasifier and the steam inlet of the biomass pyrolysis furnace; after drying, the biomass enters the pyrolysis furnace, and the pyrolysis product stream enters the gasifier; the gasifier discharge enters the gas-solid separator, and the gas phase outlet is connected to the anode inlet of the solid oxide fuel cell stack.

[0010] As a further improvement to the technical solution of the present invention, the solid oxide fuel cell power generation system includes an air expander, an air compressor, a regenerator, and a solid oxide fuel cell stack; the air compressor inlet is connected to external air, and its outlet is connected to the regenerator inlet; the regenerator outlet is connected to the cathode inlet of the solid oxide fuel cell stack; the anode outlet of the solid oxide fuel cell stack is connected to the fuel reactor inlet of the chemical looping combustion subsystem; the cathode exhaust outlet of the solid oxide fuel cell stack is connected to the hot end inlet of the regenerator, the hot end outlet of the regenerator is connected to the air expander inlet, and the air expander outlet is connected to the hot end inlet of the heat exchanger in the solar-assisted biomass gasification subsystem.

[0011] As a further improvement to the technical solution of the present invention, the solid oxide fuel cell power generation system further includes a DC-AC inverter, which is electrically connected to the solid oxide fuel cell stack and is used to convert the fuel cell output electrical energy into AC output.

[0012] 2) SOFC power generation and exhaust gas introduction into the chemical loop combustion chain: external air is preheated by an air compressor and a regenerator and then connected to the cathode inlet of the solid oxide fuel cell stack; the anode outlet of the solid oxide fuel cell stack is connected to the fuel reactor inlet of the chemical loop combustion subsystem; the gas discharged from the cathode of the solid oxide fuel cell stack passes through the hot end of the regenerator and the air expander in sequence and is then connected to the hot end inlet of the heat exchanger and discharged.

[0013] As a further improvement to the technical solution of this invention, the supercritical carbon dioxide power cycle subsystem includes a precooler, a main compressor, a low-temperature regenerator, a carbon dioxide distributor, a carbon dioxide manifold, a high-temperature regenerator, a main heat exchanger, and a carbon dioxide expander; the precooler outlet is connected to the main compressor inlet, and the main compressor outlet is connected to the carbon dioxide distributor inlet; the first outlet of the carbon dioxide distributor is connected to the low-temperature regenerator inlet, and the second outlet of the carbon dioxide distributor is connected to the high-temperature regenerator cold-side inlet; the low-temperature regenerator outlet is connected to the carbon dioxide manifold first inlet, and the high-temperature regenerator cold-side outlet is connected to the carbon dioxide manifold second inlet; the carbon dioxide manifold outlet is connected to the main heat exchanger inlet, and the main heat exchanger... The outlet is connected to the inlet of the carbon dioxide expander; the outlet of the carbon dioxide expander is connected to the hot end inlet of the low-temperature regenerator, and the hot end outlet of the low-temperature regenerator is connected to the inlet of the precooler; the first inlet on the heat source side of the main heat exchanger is connected to the outlet of the mixed gas turbine in the chemical looping combustion subsystem, and the second inlet on the heat source side of the main heat exchanger is connected to the outlet of the air turbine in the chemical looping combustion subsystem; the first outlet on the heat source side of the main heat exchanger is connected to the first inlet on the hot side of the high-temperature regenerator; the second outlet on the heat source side of the main heat exchanger is connected to the second inlet on the hot side of the high-temperature regenerator; the first outlet on the hot side of the high-temperature regenerator is connected to the first inlet of the absorption chiller in the refrigeration and heating subsystem, and the second outlet on the hot side of the high-temperature regenerator is connected to the second inlet of the absorption chiller in the refrigeration and heating subsystem.

[0014] 3) Supercritical carbon dioxide closed-loop cycle and waste heat output link: The carbon dioxide working fluid forms a closed loop through the precooler, main compressor, distributor, cold side of low temperature regenerator and high temperature regenerator, confluencer, main heat exchanger and carbon dioxide expander; the two outlets on the heat source side of the main heat exchanger are respectively connected to the first inlet and the second inlet on the hot side of the high temperature regenerator, and the first outlet and the second outlet on the hot side of the high temperature regenerator are respectively connected to the first inlet and the second inlet of the absorption chiller in the refrigeration and heating subsystem, realizing the distribution of waste heat to the terminal.

[0015] As a further improvement to the technical solution of the present invention, the chemical looping combustion subsystem includes a mixed gas turbine, an air turbine, a fuel reactor, an air reactor, an air compressor, and an air heat exchanger; the inlet of the fuel reactor is connected to the anode outlet of the solid oxide fuel cell stack; the oxygen carrier inlet of the fuel reactor is connected to the oxygen carrier outlet of the air reactor, and the exhaust outlet of the fuel reactor is connected to the inlet of the mixed gas turbine; the outlet of the air compressor is connected to the cold side inlet of the air heat exchanger, the cold side outlet of the air heat exchanger is connected to the air inlet of the air reactor, and the oxygen carrier inlet of the air reactor is connected to the oxygen carrier outlet of the fuel reactor; the oxygen-deficient air outlet of the air reactor is sequentially connected to the hot side inlet of the air heat exchanger and the inlet of the air turbine; the outlet of the mixed gas turbine is connected to the first inlet on the heat source side of the main heat exchanger in the supercritical carbon dioxide power cycle subsystem; and the outlet of the air turbine is connected to the second inlet on the heat source side of the main heat exchanger in the supercritical carbon dioxide power cycle subsystem.

[0016] 4) Coupling link between controlled exothermic chemical looping combustion and power cycle: In addition to being connected to the anode outlet of the solid oxide fuel cell stack, the oxygen carrier inlet of the fuel reactor is connected to the oxygen carrier outlet of the air reactor, and the exhaust outlet of the fuel reactor is connected to the mixed gas turbine; the air inlet of the air reactor is connected to the air compressor via an air heat exchanger, and its oxygen-deficient air outlet is connected to the air turbine via an air heat exchanger; the outlet of the mixed gas turbine and the outlet of the air turbine are respectively connected to the first and second inlets on the heat source side of the main heat exchanger of the supercritical carbon dioxide power cycle subsystem, providing two heat source side inputs for the power cycle.

[0017] As a further improvement to the technical solution of the present invention, the refrigeration and heating subsystem includes an absorption chiller, a heating heat exchanger, and a gas-liquid separator; the first inlet of the absorption chiller is connected to the first outlet on the hot side of the high-temperature regenerator in the supercritical carbon dioxide power cycle subsystem; the second inlet of the absorption chiller is connected to the second outlet on the hot side of the high-temperature regenerator in the supercritical carbon dioxide power cycle subsystem; the cooling output end of the absorption chiller is connected to the system cooling load pipeline; the first outlet of the absorption chiller is connected to the first inlet on the heat source side of the heating heat exchanger, and the first outlet on the heat source side of the heating heat exchanger is connected to the atmosphere through an exhaust pipeline; the second outlet of the absorption chiller is connected to the second inlet on the heat source side of the heating heat exchanger, and the second outlet on the heat source side of the heating heat exchanger is connected to the inlet of the gas-liquid separator; the gas phase outlet of the gas-liquid separator is connected to the carbon dioxide collection pipeline, and the liquid phase outlet of the gas-liquid separator is connected to the condensate discharge pipeline; the heat output end of the heating heat exchanger is connected to the system heat load pipeline.

[0018] 5) Terminal heating and cooling supply and gas-liquid separation link: The cooling output end of the absorption chiller is connected to the system cooling load pipeline; the first outlet of the absorption chiller is connected to the first inlet on the heat source side of the heating heat exchanger, and the first outlet on the heat source side of the heating heat exchanger is connected to the atmosphere through the exhaust pipeline; the second outlet of the absorption chiller is connected to the second inlet on the heat source side of the heating heat exchanger, and the second outlet on the heat source side of the heating heat exchanger is connected to the inlet of the gas-liquid separator; the gas phase outlet of the gas-liquid separator is connected to the carbon dioxide collection pipeline, and the liquid phase outlet is connected to the condensate discharge pipeline; the heat output end of the heating heat exchanger is connected to the system heat load pipeline.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1) The coupling of solar energy with the biomass gasification process enhances the energy utilization on the gasification side and the system's adaptability to fluctuating inputs by heating and distributing the gasifying agent along the path;

[0021] 2) Replacing the fuel cell afterburner with a chemical looping combustion unit makes it easier to organize the anode exhaust heat release process and the heat source side of the subsequent power cycle, thereby improving the recovery and utilization level of high-grade heat.

[0022] 3) By cascading the main heat exchanger, high-temperature regenerator, absorption chiller, and heating heat exchanger, waste heat can be utilized in stages while also providing both cooling and heating output, thereby improving the overall efficiency of the system.

[0023] 4) The gas-liquid separator separates the terminal fluid into gas and liquid, allowing carbon dioxide and condensate to be discharged separately for subsequent collection and utilization. Attached Figure Description

[0024] Figure 1 A schematic diagram of a SOFC (Solar-fired Combined Cooling, Heating and Power) system that couples solar energy with biomass gasification and chemical looping combustion. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1The SOFC combined cooling, heating and power system shown includes a solar-assisted biomass gasification subsystem (1), a solid oxide fuel cell (SOFC) power generation system (2), a supercritical carbon dioxide power cycle subsystem (3), a chemical looping combustion subsystem (4), and a refrigeration and heating subsystem (5). The above subsystems are connected by pipelines and valves to form an energy cascade utilization loop.

[0027] The solar-assisted biomass gasification subsystem (1) includes a water pump (101), a heat exchanger (102), a parabolic trough solar collector (103), a distributor (104), a biomass dryer (105), a biomass pyrolysis furnace (106), a biomass gasifier (107), and a gas-solid separator (108). The water pump (101) draws out external water and sends it to the inlet of the heat exchanger (102). The outlet of the heat exchanger (102) is connected to the inlet of the parabolic trough solar collector (103), and the outlet of the parabolic trough solar collector (103) is connected to the inlet of the distributor (104). The outlet of the distributor (104) is divided into two paths via pipelines. One path is connected to the gasifying agent inlet of the biomass gasifier (107), and the other path is connected to the steam inlet of the biomass pyrolysis furnace (106). The biomass outlet of the biomass dryer (105) is connected to the feed inlet of the biomass pyrolysis furnace (106), and the product flow outlet of the biomass pyrolysis furnace (106) is connected to the feed inlet of the biomass gasifier (107); the outlet of the biomass gasifier (107) is connected to the inlet of the gas-solid separator (108), and the gas phase outlet of the gas-solid separator (108) is connected to the anode inlet of the solid oxide fuel cell stack (204) in the solid oxide fuel cell power generation system (2).

[0028] The distributor (104) can be a three-way valve / valve group or an equivalent distribution device for distributing the heating medium from the collector (103) to the corresponding inlet pipes of the gasifier (107) and the pyrolysis furnace (106).

[0029] The solid oxide fuel cell power generation system (2) includes an air expander (201), an air compressor (202), a regenerator (203), a solid oxide fuel cell stack (204), and a DC / AC inverter (205). An external air inlet is connected to the inlet of the air compressor (202), the outlet of the air compressor (202) is connected to the inlet of the regenerator (203), and the outlet of the regenerator (203) is connected to the cathode inlet of the solid oxide fuel cell stack (204). The anode inlet of the solid oxide fuel cell stack (204) is connected to the gas phase outlet of the gas-solid separator (108), and the anode outlet of the solid oxide fuel cell stack (204) is connected to the inlet of the fuel reactor (403) of the chemical looping combustion subsystem (4). The cathode exhaust outlet of the solid oxide fuel cell stack (204) is connected to the hot end inlet of the regenerator (203), the hot end outlet of the regenerator (203) is connected to the inlet of the air expander (201), and the outlet of the air expander (201) is connected to the hot end inlet of the heat exchanger (102). The DC-AC inverter (205) is electrically connected to the solid oxide fuel cell stack (204) to convert the fuel cell output electrical energy into AC output.

[0030] The chemical looping combustion subsystem (4) includes a mixing turbine (401), an air turbine (402), a fuel reactor (403), an air reactor (404), an air compressor (405), and an air heat exchanger (406). The inlet of the fuel reactor (403) is connected to the anode outlet of the solid oxide fuel cell stack (204); the oxygen carrier inlet of the fuel reactor (403) is connected to the oxygen carrier outlet of the air reactor (404); and the exhaust outlet of the fuel reactor (403) is connected to the inlet of the mixing turbine (401). The outlet of the air compressor (405) is connected to the cold-side inlet of the air heat exchanger (406), and the cold-side outlet of the air heat exchanger (406) is connected to the air inlet of the air reactor (404); the oxygen carrier inlet of the air reactor (404) is connected to the oxygen carrier outlet of the fuel reactor (403); and the oxygen-deficient air outlet of the air reactor (404) is connected in sequence to the hot-side inlet of the air heat exchanger (406) and the inlet of the air turbine (402). The outlet of the mixed gas turbine (401) is connected to the first inlet on the heat source side of the main heat exchanger (307) of the supercritical carbon dioxide power cycle subsystem (3); the outlet of the air turbine (402) is connected to the second inlet on the heat source side of the main heat exchanger (307).

[0031] The supercritical carbon dioxide power cycle subsystem (3) includes a precooler (301), a main compressor (302), a low-temperature regenerator (303), a carbon dioxide distributor (304), a carbon dioxide concentrator (305), a high-temperature regenerator (306), a main heat exchanger (307), and a carbon dioxide expander (308). The outlet of the precooler (301) is connected to the inlet of the main compressor (302), and the outlet of the main compressor (302) is connected to the inlet of the carbon dioxide distributor (304). The first outlet of the carbon dioxide distributor (304) is connected to the inlet of the low-temperature regenerator (303) in sequence, and the second outlet of the carbon dioxide distributor (304) is connected to the cold side inlet of the high-temperature regenerator (306) in sequence. The outlet of the low-temperature regenerator (303) is connected to the first inlet of the carbon dioxide manifold (305), and the cold side outlet of the high-temperature regenerator (306) is connected to the second inlet of the carbon dioxide manifold (305). The outlet of the carbon dioxide manifold (305) is connected to the inlet of the main heat exchanger (307), and the outlet of the main heat exchanger (307) is connected to the inlet of the carbon dioxide expander (308). The outlet of the carbon dioxide expander (308) is connected to the hot end inlet of the low-temperature regenerator (303), and the hot end outlet of the low-temperature regenerator (303) is connected to the inlet of the precooler (301), thus forming a closed loop. The first inlet on the heat source side of the main heat exchanger (307) is connected to the outlet of the mixed gas turbine (401), and the second inlet on the heat source side of the main heat exchanger (307) is connected to the outlet of the air turbine (402). The first outlet on the heat source side of the main heat exchanger (307) is connected to the first inlet on the hot side of the high-temperature regenerator (306), and the second outlet on the heat source side of the main heat exchanger (307) is connected to the second inlet on the hot side of the high-temperature regenerator (306). The first outlet on the hot side of the high-temperature regenerator (306) is connected to the first inlet of the absorption chiller (501) in the refrigeration and heating subsystem (5), and the second outlet on the hot side of the high-temperature regenerator (306) is connected to the second inlet of the absorption chiller (501).

[0032] The refrigeration and heating subsystem (5) includes an absorption chiller (501), a heating heat exchanger (502), and a gas-liquid separator (503). The first inlet of the absorption chiller (501) is connected to the first outlet on the hot side of the high-temperature regenerator (306), and the second inlet of the absorption chiller (501) is connected to the second outlet on the hot side of the high-temperature regenerator (306); the cooling capacity output end of the absorption chiller (501) is connected to the system cooling load pipeline. The first outlet of the absorption chiller (501) is connected to the first inlet on the heat source side of the heating heat exchanger (502), and the first outlet on the heat source side of the heating heat exchanger (502) is connected to the exhaust pipeline and discharged into the atmosphere; the second outlet of the absorption chiller (501) is connected to the second inlet on the heat source side of the heating heat exchanger (502), and the second outlet on the heat source side of the heating heat exchanger (502) is connected to the inlet of the gas-liquid separator (503). The gas phase outlet of the gas-liquid separator (503) is connected to the carbon dioxide collection pipeline, and the liquid phase outlet is connected to the condensate discharge pipeline. The heat output end of the heating heat exchanger (502) is connected to the system heat load pipeline.

[0033] The absorption chiller (501) can adopt a single-effect or double-effect absorption cycle structure; this embodiment does not limit its specific internal structure, but only limits its interface connection with the high-temperature regenerator (306), the heating heat exchanger (502) and the cold load pipeline.

[0034] System working process:

[0035] During system operation, external water is first heated by a water pump (101) and then enters a heat exchanger (102). It then enters a parabolic trough solar collector (103) for further heating, gasification, and superheating. The heated medium is then distributed by a distributor (104) and enters the gasifying agent inlet of the biomass gasifier (107) and the steam inlet of the biomass pyrolysis furnace (106), respectively. The biomass is dried by a dryer (105) and then enters the pyrolysis furnace (106). The pyrolysis product stream enters the gasifier (107) to generate syngas. The syngas then flows from... After being discharged from the gasifier (107), the gas enters the gas-solid separator (108) to separate the entrained solid particles. The clean syngas is drawn out from the gas phase outlet of the gas-solid separator (108) and sent to the anode side of the solid oxide fuel cell stack (204). The external air is pressurized by the air compressor (202) and preheated by the regenerator (203) before entering the cathode side of the solid oxide fuel cell stack (204). The electrical energy output by the solid oxide fuel cell stack (204) is connected to the grid or supplied to the load via the inverter (205).

[0036] After the electrochemical reaction, the oxygen-deficient air on the cathode side of the solid oxide fuel cell stack (204) is discharged from the cathode exhaust port of the solid oxide fuel cell stack (204), flows through the hot side of the regenerator (203), heats the air from the air compressor (202), cools itself, and then enters the air expander (201) to expand and do work, recovering some energy. Finally, it enters the hot side of the heat exchanger (102) to preheat the water from the water source, and then is discharged into the atmosphere. The tail gas from the anode of the solid oxide fuel cell stack (204) enters the fuel reactor (403) and undergoes a reduction reaction with the oxygen carrier from the air reactor (404). The reduced oxygen carrier is transported to the air reactor (404). The external air is pressurized by the air compressor (405) and preheated by the cold side of the air heat exchanger (406) before entering the air reactor (404). In the air reactor (404), the reduced oxygen carrier reacts with oxygen in the air to regenerate the oxidized oxygen carrier and release heat. The oxygen-deficient air produced after the reaction is discharged from the air reactor (404). The exhaust gas from the fuel reactor (403) enters the mixed gas turbine (401) to expand and do work. The high-temperature oxygen-deficient air discharged from the air reactor (404) passes through the hot side of the air heat exchanger (406) to heat the air from the air compressor (405) and then enters the air turbine (402) to expand and do work. The exhaust gas from the mixed gas turbine (401) and the air turbine (402) still have a high temperature. They serve as two heat sources and enter the first and second inlets of the heat source side of the main heat exchanger (307) to provide heat source side input for the supercritical carbon dioxide power cycle subsystem (3).

[0037] The supercritical carbon dioxide power cycle subsystem (3) uses carbon dioxide as the circulating working fluid. The low-temperature, low-pressure carbon dioxide working fluid is cooled by the precooler (301) and then compressed to a supercritical state by the main compressor (302). The high-pressure carbon dioxide working fluid is divided into two streams by the carbon dioxide splitter (304): one stream flows through the cold side of the low-temperature regenerator (303) to absorb heat; the other stream directly enters another passage on the cold side of the high-temperature regenerator (306). After the two streams are mixed in the carbon dioxide confluencer (305), they enter the main heat exchanger (307) and are heated to the designed high-temperature and high-pressure state by the two high-temperature exhausts from the chemical loop combustion subsystem (4). The high-temperature and high-pressure supercritical carbon dioxide then enters the carbon dioxide expander (308) to expand and do work. After doing work, the carbon dioxide becomes a medium-temperature and medium-pressure state and flows through the hot side of the low-temperature regenerator (303) and the precooler (301) in sequence, transferring heat to the working fluid at the outlet of the main compressor and the external cooling medium, while being cooled itself, completing a closed loop. The heat source from the chemical loop combustion subsystem (4) (i.e., the exhaust gas from the mixed gas turbine 401 and the air turbine 402) releases heat in the main heat exchanger (307), and its temperature decreases, but there is still usable medium-low temperature waste heat. After these two fluids are discharged from the heat source side outlet of the main heat exchanger (307), they enter the heat-side absorption chiller (501) of the high-temperature regenerator (306) to provide two waste heat inputs.

[0038] Two streams of waste heat fluid discharged from the hot side of the high-temperature regenerator 306 serve as the driving heat source for the absorption chiller (501), which supplies cooling to the cooling load pipeline at its cooling capacity output end. The heat source fluid discharged from the absorption chiller (501) is divided into two streams: the first stream enters the first passage on the heat source side of the heating heat exchanger (502), where it releases its remaining heat to the system's heat load before being discharged into the atmosphere through the exhaust pipe; the second stream enters the second passage on the heat source side of the heating heat exchanger (502), where it continues to release heat before entering the gas-liquid separator (503). In the gas-liquid separator (503), the gas phase (CO2) and the liquid phase (condensate) are separated. The gas phase is led out through the carbon dioxide collection pipe for subsequent compression, storage, or utilization; the liquid phase is discharged through the condensate discharge pipe.

[0039] The beneficial effects of this invention are as follows:

[0040] 1) By deeply coupling the parabolic trough solar collector with the biomass gasification process, the gasifying agent / steam entering the gasifier and pyrolysis furnace is preheated directly, which effectively improves the grade of the gasifying agent, enhances the gasification reaction efficiency and syngas quality, and improves the system's adaptability and absorption capacity to solar energy fluctuations.

[0041] 2) The chemical loop combustion unit replaces the traditional fuel cell afterburner to perform flameless oxidation of SOFC anode exhaust gas. This process has controllable heat release and good temperature matching. After the exhaust gas and oxygen-deficient air drive the mixed gas turbine and air turbine to do work, it provides two stable and easily controllable high-grade heat sources for the downstream supercritical carbon dioxide power cycle, which greatly improves the level of high-grade heat recovery and utilization.

[0042] 3) A cascaded waste heat utilization chain of "main heat exchanger - high temperature regenerator - absorption chiller - heating heat exchanger" was constructed, realizing the energy cascade utilization from high-grade power generation to low-grade cooling / heating, which significantly improved the overall energy efficiency of the system.

[0043] 4) At the end of the system, the exhaust gas after waste heat utilization is separated by a gas-liquid separator, which realizes the separate export and collection of carbon dioxide and condensate, thereby improving the environmental protection and resource utilization rate of the system.

Claims

1. A solar-coupled SOFC (Solar-Powered Combined Cooling, Heating and Power) system combining solar energy with biomass gasification and chemical looping combustion, characterized in that, The system includes a solar-assisted biomass gasification subsystem (1), a solid oxide fuel cell power generation system (2), a supercritical carbon dioxide power cycle subsystem (3), a chemical looping combustion subsystem (4), and a refrigeration and heating subsystem (5). The solar-assisted biomass gasification subsystem (1) utilizes solar energy to react the gasifying agent, biomass, and gasifying agent to generate syngas. The syngas is supplied to the solid oxide fuel cell power generation system (2) for power generation. The anode tail gas generated by the solid oxide fuel cell power generation system (2) enters the chemical looping combustion subsystem (4) for flameless oxidation. The high-temperature heat released drives the supercritical carbon dioxide power cycle subsystem (3) to generate electricity in stages. The discharged medium- and low-temperature waste heat is supplied to the refrigeration and heating subsystem (5) for refrigeration and heating, and finally achieves gas-liquid separation and carbon dioxide enrichment.

2. The SOFC combined cooling, heating and power system according to claim 1, characterized in that, The solar-assisted biomass gasification subsystem (1) includes a water pump (101), a heat exchanger (102), a parabolic trough solar collector (103), a distributor (104), a biomass dryer (105), a biomass pyrolysis furnace (106), a biomass gasification furnace (107), and a gas-solid separator (108). The inlet of the water pump (101) is connected to an external water source, and its outlet is connected to the inlet of the heat exchanger (102). The outlet of the heat exchanger (102) is connected to the inlet of the parabolic trough solar collector (103), and the outlet of the parabolic trough solar collector (103) is connected to the inlet of the distributor (104). The outlet of the distributor (104) is connected to the inlet of the distributor (104). The inlet pipe is divided into two paths, one of which is connected to the gasifying agent inlet of the biomass gasifier (107), and the other is connected to the steam inlet of the biomass pyrolysis furnace (106); the biomass outlet of the biomass dryer (105) is connected to the feed inlet of the biomass pyrolysis furnace (106), and the product flow outlet of the biomass pyrolysis furnace (106) is connected to the feed inlet of the biomass gasifier (107); the outlet of the biomass gasifier (107) is connected to the inlet of the gas-solid separator (108); and the gas phase outlet of the gas-solid separator (108) is connected to the anode inlet of the solid oxide fuel cell stack (204) in the solid oxide fuel cell power generation system (2).

3. The SOFC combined cooling, heating and power system according to claim 1, characterized in that, The solid oxide fuel cell power generation system (2) includes an air expander (201), an air compressor (202), a regenerator (203), and a solid oxide fuel cell stack (204); the air compressor (202) has an inlet connected to the outside air and an outlet connected to the inlet of the regenerator (203); the regenerator (203) outlet is connected to the cathode inlet of the solid oxide fuel cell stack (204); the anode outlet of the solid oxide fuel cell stack (204) is connected to the inlet of the fuel reactor (403) in the chemical looping combustion subsystem (4); the cathode exhaust outlet of the solid oxide fuel cell stack (204) is connected to the hot end inlet of the regenerator (203); the hot end outlet of the regenerator (203) is connected to the inlet of the air expander (201); and the air expander (201) outlet is connected to the hot end inlet of the heat exchanger (102) in the solar-assisted biomass gasification subsystem (1).

4. The SOFC combined cooling, heating and power system according to claim 3, characterized in that, The solid oxide fuel cell power generation system (2) also includes a DC-AC inverter (205), which is electrically connected to the solid oxide fuel cell stack (204) and is used to convert the fuel cell output electrical energy into AC output.

5. The SOFC combined cooling, heating and power system according to claim 1, characterized in that, The supercritical carbon dioxide power cycle subsystem (3) includes a precooler (301), a main compressor (302), a low-temperature regenerator (303), a carbon dioxide distributor (304), a carbon dioxide concentrator (305), a high-temperature regenerator (306), a main heat exchanger (307), and a carbon dioxide expander (308); the outlet of the precooler (301) is connected to the inlet of the main compressor (302), and the outlet of the main compressor (302) is connected to the inlet of the carbon dioxide distributor (304); the carbon dioxide... The first outlet of the splitter (304) is connected to the inlet of the low-temperature regenerator (303), and the second outlet of the carbon dioxide splitter (304) is connected to the cold-side inlet of the high-temperature regenerator (306); the outlet of the low-temperature regenerator (303) is connected to the first inlet of the carbon dioxide manifold (305), and the cold-side outlet of the high-temperature regenerator (306) is connected to the second inlet of the carbon dioxide manifold (305); the outlet of the carbon dioxide manifold (305) is connected to the inlet of the main heat exchanger (307), and the main heat exchanger (304) is connected to the inlet of the main heat exchanger (306). 7) The outlet is connected to the inlet of the carbon dioxide expander (308); the outlet of the carbon dioxide expander (308) is connected to the hot end inlet of the low-temperature regenerator (303), and the hot end outlet of the low-temperature regenerator (303) is connected to the inlet of the precooler (301); the first inlet on the heat source side of the main heat exchanger (307) is connected to the outlet of the mixed gas turbine (401) in the chemical loop combustion subsystem (4), and the second inlet on the heat source side of the main heat exchanger (307) is connected to the outlet of the air turbine (402) in the chemical loop combustion subsystem (4). The first outlet on the heat source side of the main heat exchanger (307) is connected to the first inlet on the heat side of the high-temperature regenerator (306); the second outlet on the heat source side of the main heat exchanger (307) is connected to the second inlet on the heat side of the high-temperature regenerator (306); the first outlet on the heat side of the high-temperature regenerator (306) is connected to the first inlet of the absorption chiller (501) in the refrigeration and heating subsystem (5); and the second outlet on the heat side of the high-temperature regenerator (306) is connected to the second inlet of the absorption chiller (501) in the refrigeration and heating subsystem (5).

6. The SOFC combined cooling, heating and power system according to claim 1, characterized in that, The chemical loop combustion subsystem (4) includes a mixed gas turbine (401), an air turbine (402), a fuel reactor (403), an air reactor (404), an air compressor (405), and an air heat exchanger (406); the inlet of the fuel reactor (403) is connected to the anode outlet of the solid oxide fuel cell stack (204); the oxygen carrier inlet of the fuel reactor (403) is connected to the oxygen carrier outlet of the air reactor (404), and the exhaust outlet of the fuel reactor (403) is connected to the inlet of the mixed gas turbine (401); the outlet of the air compressor (405) is connected to the cold side inlet of the air heat exchanger (406), and the air... The cold-side outlet of the gas heat exchanger (406) is connected to the air inlet of the air reactor (404), and the oxygen carrier inlet of the air reactor (404) is connected to the oxygen carrier outlet of the fuel reactor (403); the oxygen-deficient air outlet of the air reactor (404) is connected in sequence to the hot-side inlet of the air heat exchanger (406) and the inlet of the air turbine (402); the outlet of the mixed gas turbine (401) is connected to the first inlet on the heat source side of the main heat exchanger (307) in the supercritical carbon dioxide power cycle subsystem (3); the outlet of the air turbine (402) is connected to the second inlet on the heat source side of the main heat exchanger (307) in the supercritical carbon dioxide power cycle subsystem (3).

7. A solar-coupled SOFC (Solar-Powered Combined Cooling, Heating and Power) system based on biomass gasification and chemical looping combustion as described in claim 1, characterized in that, The refrigeration and heating subsystem (5) includes an absorption chiller (501), a heating heat exchanger (502), and a gas-liquid separator (503); the first inlet of the absorption chiller (501) is connected to the first outlet on the heat side of the high-temperature regenerator (306) in the supercritical carbon dioxide power cycle subsystem (3); the second inlet of the absorption chiller (501) is connected to the second outlet on the heat side of the high-temperature regenerator (306) in the supercritical carbon dioxide power cycle subsystem (3); the cooling capacity output end of the absorption chiller (501) is connected to the system cooling load pipeline; the first outlet of the absorption chiller (501) is connected to the gas-liquid separator (503). The first inlet of the heat exchanger (502) on the heat source side is connected, and the first outlet of the heat exchanger (502) on the heat source side is connected to the atmosphere through an exhaust pipe; the second outlet of the absorption chiller (501) is connected to the second inlet of the heat exchanger (502) on the heat source side, and the second outlet of the heat exchanger (502) on the heat source side is connected to the inlet of the gas-liquid separator (503); the gas phase outlet of the gas-liquid separator (503) is connected to the carbon dioxide collection pipe, and the liquid phase outlet of the gas-liquid separator (503) is connected to the condensate discharge pipe; the heat output end of the heat exchanger (502) is connected to the system heat load pipe.

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