Rural energy comprehensive utilization system and working method therefor

Abstract

Provided are a rural energy comprehensive utilization system and a working method therefor. The system comprises a geothermal energy utilization system and a biomass energy utilization system, wherein the geothermal energy utilization system comprises a geothermal well which is sequentially connected to a geothermal water treatment assembly, a superheater, an evaporator, a steam turbine, a condenser, an air preheater, a heat network heat exchanger, and a heat pipe heat exchanger; and the biomass energy utilization system comprises a biomass fermentation system and a biomass pyrolysis system. The biomass fermentation system comprises a biogas digester that is sequentially connected to a desulfurization tower and a carbon dioxide absorption tower, the carbon dioxide absorption tower being connected to an internal combustion engine. The biomass pyrolysis system comprises a baking device and a pyrolysis furnace, which are connected in sequence, the pyrolysis furnace being connected to the carbon dioxide absorption tower, and the baking device being connected to the superheater, the evaporator and a greenhouse, which greenhouse is connected to each of the air preheater and the internal combustion engine.

Description

A rural energy integrated utilization system and its working method

[0001] This application claims priority to Chinese Patent Application No. 202411180409.6, filed on August 27, 2024, entitled "A Rural Energy Comprehensive Utilization System and Its Working Method", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of integrated energy utilization technology, and more specifically, to a rural integrated energy utilization system and its working method. Background Technology

[0003] With the rapid development of the rural economy, the demand for high-quality commercial energy in agricultural production continues to increase, and the contradiction between energy supply and demand in rural areas is becoming increasingly prominent. On the one hand, the consumption of traditional fossil fuels generates a large amount of greenhouse gases, leading to environmental degradation; on the other hand, rural China still relies mainly on firewood and straw as fuel, resulting in serious resource waste. Under the "dual carbon" target, strengthening the integration of modern agriculture and the energy system is conducive to the integrated development of rural industries, the cultivation of new agricultural business models, and, more importantly, to promoting the transformation and upgrading of the rural workforce.

[0004] Biomass energy, as a convenient, clean, and high-quality energy source, can not only alleviate energy pressure but also play a vital role in increasing farmers' income, improving the living environment, protecting forests and grasslands, and maintaining ecological balance. Statistics show that my country generates 7.28 × 10⁻⁶ biomass energy annually in rural areas. 8 1 ton of straw, 39.26 × 10 8 Tons of livestock and poultry manure and 482.4 × 10 8 Tons of organic wastewater cause huge pollution to the environment because it cannot be effectively utilized.

[0005] Geothermal resources are a renewable and clean energy source with large reserves and wide distribution. They are characterized by being clean and environmentally friendly, versatile, stable, and recyclable. Compared to wind and solar energy, they are not affected by external factors such as seasons, climate, or diurnal variations, making them a realistic and competitive new energy source. With increasing environmental awareness, the rational development and utilization of geothermal resources is gaining popularity. However, geothermal energy still faces the problem of low energy efficiency during use.

[0006] Therefore, how to solve the problem of low utilization rate of biomass energy in rural areas is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a rural energy comprehensive utilization system that uses agricultural and forestry biomass, human and animal excrement, and wastewater sludge generated from various agricultural activities as raw materials for biomass utilization. This not only realizes the resource utilization of waste, but also improves the rural living environment, effectively controls agricultural production pollution, and rationally combines geothermal energy and biomass energy with rural production and life. It can meet the local residents' heat and electricity needs. The geothermal energy utilization system and the biomass energy utilization system complement each other and have complementary advantages, realizing the cascade utilization of energy and improving energy utilization efficiency.

[0008] Another objective of this invention is to provide a method for operating a rural energy integrated utilization system that includes the above-mentioned rural energy integrated utilization system, which can enhance the economic benefits and environmental benefits of agricultural activities.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A rural energy integrated utilization system includes a geothermal energy utilization system and a biomass energy utilization system;

[0011] The geothermal energy utilization system includes a geothermal well, which is connected in sequence to a geothermal water treatment component, a steam turbine, a first generator, a condenser, an air preheater, a heat network heat exchanger, and a heat pipe heat exchanger. The geothermal water treatment component is connected to a superheater and an evaporator, respectively. Both the superheater and the evaporator are connected to the steam turbine. The heat pipe heat exchanger is equipped with gravity heat pipes for transferring heat to the biogas digester. The condenser is used for heating or supplying hot water to residential areas. The heat network heat exchanger is used for heating the aquaculture farm. The hot water after heat exchange in the heat pipe heat exchanger is supplied to the fishpond.

[0012] Biomass energy utilization systems include biomass fermentation systems and biomass pyrolysis systems;

[0013] The biomass fermentation system includes a slurry tank connected to a biogas digester, the biogas digester being connected in sequence to a desulfurization tower and a carbon dioxide absorption tower, the carbon dioxide absorption tower being connected to a gas treatment component and an internal combustion engine, and the internal combustion engine being connected to a second generator.

[0014] The biomass pyrolysis system includes a baking device and a pyrolysis furnace connected in sequence. The baking device is used to preheat straw and rice husks produced in farmland. The pyrolysis furnace is connected to a gas treatment component. The first induced draft fan is connected to the output end of the internal combustion engine and the pyrolysis furnace through a three-way valve. The first induced draft fan is connected to the baking device. The baking device is connected in sequence to a superheater, an evaporator, and a greenhouse. The greenhouse is connected to an air preheater and a fishpond, respectively. The air preheater is connected to the internal combustion engine.

[0015] Preferably, the geothermal water treatment assembly includes a water pump connected to a geothermal well, a first flash evaporator connected to the water pump, the first flash evaporator being connected to a superheater and a second flash evaporator, and the second flash evaporator being connected to an evaporator.

[0016] Preferably, the gas treatment assembly includes a carbon dioxide regeneration tower connected to a carbon dioxide absorption tower, the carbon dioxide regeneration tower connected to a carbon dioxide storage tank, the carbon dioxide storage tank connected to a pyrolysis furnace, and a blower provided between the carbon dioxide storage tank and the pyrolysis furnace.

[0017] Preferably, a methane storage tank and an air pump are provided between the carbon dioxide absorption tower and the internal combustion engine. The carbon dioxide absorption tower is connected to the methane storage tank, the methane storage tank is connected to the air pump, the air pump is connected to the second induced draft fan and the internal combustion engine through a three-way valve, and the second induced draft fan is connected to the air preheater.

[0018] Preferably, a three-way valve is installed on the pipeline connecting the greenhouse, the air preheater, and the fishpond. The first port of the three-way valve is connected to the greenhouse, the second port is connected to the air preheater, and the third port is connected to the fishpond.

[0019] Preferably, the pyrolysis furnace is connected to the bio-oil storage tank and the biochar recovery tank respectively.

[0020] Preferably, the pipeline connecting the slurry tank and the biogas digester is equipped with a screw pump for controlling the feeding of materials from the slurry tank to the biogas digester.

[0021] Preferably, the raw materials for the homogenizing tank include organic domestic waste, human and animal excrement, and sludge from fish ponds generated in residential areas and farms, while the biomass pyrolysis raw materials for the pyrolysis furnace are straw, rice husks, and biogas residue and biogas slurry produced from farmland.

[0022] Preferably, the first and second generators are used to supply power to farms, greenhouses, fish ponds, pyrolysis furnaces, and residential areas.

[0023] A method for operating a rural energy integrated utilization system, applied to the aforementioned rural energy integrated utilization system, the method comprising:

[0024] High-temperature geothermal water from the geothermal well is pumped out by a water pump. Saturated steam from the first flash evaporator passes through a heat exchanger and enters the high-pressure cylinder of the turbine to expand and do work, driving the first generator to generate electricity. Saturated water from the first flash evaporator passes through an evaporator and enters the low-pressure cylinder of the turbine to expand and do work, driving the first generator to generate electricity. The exhaust steam that has done work condenses in the condenser. The condensed high-temperature geothermal water passes through the air preheater, the heat network heat exchanger, and the heat pipe heat exchanger in sequence, and finally flows into the fishpond.

[0025] The biogas feedstock in the homogenization tank is pumped into the biogas digester by a screw pump, fermented in the biogas digester, and the biogas produced passes through the desulfurization tower and the carbon dioxide absorption tower in sequence. The generated carbon dioxide-rich liquid enters the carbon dioxide regeneration tower, and the carbon dioxide is stored in the carbon dioxide storage tank after regeneration. It is then introduced into the pyrolysis furnace by a blower. The generated methane is pumped into the internal combustion engine by a gas pump.

[0026] Straw and rice husks from farmland are mixed with biogas residue and biogas slurry from biogas digesters and fed into a baking device as biomass pyrolysis feedstock. After baking pretreatment, the mixture is pyrolyzed in a pyrolysis furnace. The high-temperature carbon dioxide gas produced by the pyrolysis furnace and the high-temperature flue gas produced by the internal combustion engine enter the baking device under the action of a second induced draft fan. The mixed gas coming out of the baking device passes through a heater and an evaporator for heat exchange. The low-temperature mixed gas after heat exchange flows into the greenhouse to promote plant photosynthesis. The oxygen-rich air produced by plant photosynthesis enters the fishpond and the internal combustion engine respectively, oxygenating the fishpond and providing oxygen for the combustion of methane in the internal combustion engine. The combustion of the internal combustion engine drives a second generator to generate electricity.

[0027] Compared with the prior art, the present invention provides a rural energy comprehensive utilization system, which has the following beneficial effects:

[0028] (1) The present invention uses gravity heat pipes to transfer the heat of geothermal tailwater to the biogas digester. Gravity heat pipes transfer heat quickly. Based on the uniformity of the temperature of gravity heat pipes, the temperature difference of biogas liquid in different parts of the biogas digester can be reduced, thereby improving the biogas fermentation effect.

[0029] (2) This invention coordinates the gases generated by each system to achieve gas recycling. Separating carbon dioxide gas from biogas and using it as an inert atmosphere in the pyrolysis furnace can improve the yield of bio-oil and reduce the cost of inert gas preparation. The high-temperature mixed gas after pyrolysis is mixed with the high-temperature flue gas generated by the internal combustion engine and cooled down through multiple heat exchanges, which can be used as an atmosphere for photosynthesis of plants in greenhouses. Part of the oxygen-rich air generated by the greenhouse plants is introduced into the internal combustion engine to promote biogas combustion, improve the combustion efficiency of the internal combustion engine, and reduce the generation of harmful gases. The other part is introduced into the fishpond to oxygenate the fishpond.

[0030] (3) This invention uses human and animal excrement, wastewater and sludge produced in various agricultural activity sites as fermentation raw materials. The fermented biogas slurry and biogas residue have unstable components and varied thermal properties. After being mixed with agricultural and forestry biomass, they are pyrolyzed in a pyrolysis furnace. This not only produces biomass fuel with higher calorific value, but also produces biochar with high stability and easier preservation. It can be directly used in farmland and greenhouses to increase the organic carbon content of the soil and regulate the soil water holding capacity. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 is a schematic diagram of the rural energy comprehensive utilization system provided by the present invention;

[0033] Figure 2 is a flowchart illustrating the working method of the rural energy comprehensive utilization system provided by the present invention.

[0034] Figure reference numerals: 1-Geothermal well; 2-Geothermal water treatment components; 201-Water pump; 202-First flash evaporator; 203-Second flash evaporator; 3-Steam turbine; 4-First generator; 5-Condenser; 6-Air preheater; 7-Heat network heat exchanger; 8-Heat pipe heat exchanger; 9-Superheater; 10-Evaporator; 11-Biogas digester; 12-Gravity heat pipe; 13-Residential area; 14-Fish farm; 15-Fishpond; 16-Pulverizing tank; 17-Desulfurization tower; 18-Oxygen dioxide Carbon absorption tower; 19-Gas processing assembly; 191-Carbon dioxide regeneration tower; 192-Carbon dioxide storage tank; 20-Internal combustion engine; 21-Second generator; 22-Farmland; 23-Baking device; 24-Pyrolysis furnace; 25-First induced draft fan; 26-Three-way valve; 27-Greenhouse; 28-Blower; 29-Methane storage tank; 30-Gas pump; 31-Second induced draft fan; 32-Bio-oil storage tank; 33-Biochar recovery tank; 34-Screw pump. Detailed Implementation

[0035] 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.

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] The core of this invention is to provide a comprehensive rural energy utilization system that uses agricultural and forestry biomass, human and animal excrement, and wastewater sludge generated from various agricultural activities as raw materials for biomass utilization. This not only realizes the resource utilization of waste but also improves the rural living environment and effectively controls agricultural pollution. By rationally combining geothermal energy and biomass energy with rural production and daily life, it can meet the local residents' heating and electricity needs. The geothermal energy utilization system and the biomass energy utilization system complement each other, achieving cascaded energy utilization and improving energy efficiency. Another core aspect of this invention is to provide a working method for the aforementioned comprehensive rural energy utilization system, which can enhance the economic benefits and environmental advantages of agricultural activities.

[0038] Please refer to Figure 1. A rural energy integrated utilization system includes a geothermal energy utilization system and a biomass energy utilization system, which rationally integrates geothermal energy and biomass energy with rural production and daily life, realizing the cascade utilization of rural biomass energy and geothermal energy, and improving energy utilization efficiency. The geothermal energy utilization system includes a geothermal well 1, which is sequentially connected to a geothermal water treatment component 2, a steam turbine 3, a first generator 4, a condenser 5, an air preheater 6, a heat network heat exchanger 7, and a heat pipe heat exchanger 8. The geothermal water treatment component 2 is connected to a superheater 9 and an evaporator 10, respectively. Both the superheater 9 and the evaporator 10 are connected to the steam turbine 3. The high-temperature geothermal water from the geothermal well 1 enters the superheater 9 and the evaporator 10 for secondary treatment after passing through the geothermal water treatment component 2, and then enters the steam turbine 3. The turbine 3 expands and does work, driving the first generator 4 to generate electricity. The exhaust steam from the turbine 3 condenses in the condenser 5. The condensed high-temperature geothermal water passes through the air preheater 6, the heat network heat exchanger 7, and the heat pipe heat exchanger 8 in sequence, and finally flows into the fishpond 15. The geothermal water in the condenser 5 has a high temperature, and the released heat can be transported over long distances for heating or hot water supply to the residential area 13. The heat network heat exchanger 7 provides heating to the aquaculture farm 14 through heat exchange. The heat pipe heat exchanger 8 is equipped with gravity heat pipes 12 for transferring heat to the biogas digester 11. By setting gravity heat pipes 12 in the heat pipe heat exchanger 8, the heat of the geothermal tail water is transferred to the biogas digester 11. Based on the uniform temperature of the gravity heat pipes 12, the temperature difference of the biogas liquid in different parts of the biogas digester 11 can be reduced, thereby improving the biogas fermentation effect.

[0039] The biomass energy utilization system includes a biomass fermentation system and a biomass pyrolysis system. The biomass fermentation system includes a homogenizing tank 16 connected to a biogas digester 11. The biogas digester 11 is connected in sequence to a desulfurization tower 17 and a carbon dioxide absorption tower 18. The carbon dioxide absorption tower 18 is connected to a gas treatment component 19 and an internal combustion engine 20. The biogas feedstock in the homogenizing tank is fermented in the biogas digester 11. The generated biogas passes through the desulfurization tower 17 and the carbon dioxide absorption tower 18 in sequence. The generated carbon dioxide-rich liquid enters the gas treatment component 19. The pyrolysis furnace 24 is connected to the gas treatment component 19. The carbon dioxide-rich liquid is processed and stored in the gas treatment component 19 and enters the pyrolysis furnace 24 when used as an inert atmosphere for the pyrolysis furnace 24, which can improve the bio-oil yield and reduce the preparation cost of inert gas. The gas processed by the carbon dioxide absorption tower 18 is methane. When in use, the methane is passed into the internal combustion engine 20 for combustion. The internal combustion engine 20 is connected to a second generator 21. The combustion in the internal combustion engine 20 drives the second generator 21 to generate electricity.

[0040] The biomass pyrolysis system includes a roasting device 23 and a pyrolysis furnace 24 connected in sequence. The roasting device 23 is used to preheat straw, rice husks, etc. produced by farmland 22. The straw and other materials produced by farmland 22 are first preheated by the roasting device 23 and then transferred to the pyrolysis furnace 24 for pyrolysis. The pyrolysis furnace 24 is connected to a gas treatment component 19, which provides inert gas to the pyrolysis furnace 24 to improve the bio-oil yield. The first induced draft fan 25 is connected to the output end of the internal combustion engine 20 and the pyrolysis furnace 24 through a three-way valve 26. The first induced draft fan 25 is connected to the roasting device 23. The high-temperature flue gas generated by the combustion of the internal combustion engine 20 and the high-temperature gas generated by the pyrolysis furnace 24 are mixed under the action of the first induced draft fan 25. The gas enters the baking device 23 to provide a suitable temperature for biomass baking. The baking device 23 is connected in sequence to the superheater 9, the evaporator 10, and the greenhouse 27. The mixed gas coming out of the baking device 23 passes through the superheater 9 and the heater to heat the geothermal water and improve the geothermal power generation efficiency. The low-temperature mixed gas flow after heat exchange enters the greenhouse 27 to promote the photovoltaic effect of plants. The greenhouse 27 is connected to the air preheater 6 and the fishpond 15 respectively. The air preheater 6 is connected to the internal combustion engine 20. Part of the oxygen-rich air generated by the greenhouse 27 enters the air preheater 6 for heating. After heating, it enters the internal combustion engine 20 to mix with methane for combustion. The other part is introduced into the fishpond 15 to oxygenate the fishpond 15.

[0041] The pyrolysis furnace 24 is used to pyrolyze straw and other materials, which is highly efficient, pollution-free, and has low processing costs. The heat exchanger 7 uses a heat network, which is simple and reliable to operate. The waste heat from the flue gas of the internal combustion engine 20 is used to heat saturated steam into superheated steam, which then enters the low-pressure cylinder of the turbine 3. This improves the thermal energy conversion efficiency, thereby increasing output power and achieving efficient and economical power generation from renewable energy sources, with significant energy-saving and environmental protection effects. Gravity heat pipes 12 are used to transfer heat from geothermal tailwater to the biogas digester 11 as a constant-temperature heat source. The heat transfer speed is fast, and based on the uniform temperature of the gravity heat pipes 12, the temperature difference of the biogas slurry in different parts of the biogas digester 11 can be reduced, improving the biogas fermentation effect.

[0042] The rural energy integrated utilization system set up in the above manner uses agricultural and forestry biomass, human and animal excrement, and wastewater sludge generated from various agricultural activities as raw materials for biomass utilization. It can realize the resource utilization of waste, improve the rural living environment, effectively control agricultural production pollution, and rationally combine geothermal energy and biomass energy. It can also recover and utilize the waste heat from high-temperature geothermal tailwater and biogas power generation tail gas to make full use of energy. The geothermal energy utilization system and the biomass energy utilization system complement each other to achieve the cascade utilization of energy and improve the utilization rate of rural biomass energy and geothermal energy.

[0043] In the above embodiment, the geothermal water treatment component 2 includes a water pump 201 connected to the geothermal well 1 and a first flash evaporator 202 connected to the water pump 201. The first flash evaporator 202 is connected to the superheater 9 and the second flash evaporator 203 respectively, and the second flash evaporator 203 is connected to the evaporator 10.

[0044] It should be noted that the high-temperature geothermal water is pumped from the geothermal well 1 by the water pump 201 and goes to the first flash evaporator 202. The saturated steam from the first flash evaporator 202 passes through the superheater 9 and then goes to the high-pressure cylinder of the turbine 3 to expand and do work, driving the first generator 4 to generate electricity. The saturated water from the first flash evaporator 202 passes through the evaporator 10 and then enters the low-pressure cylinder of the turbine 3 to expand and do work, driving the first generator 4 to generate electricity. By setting up two flash evaporators, the utilization rate of the high-temperature geothermal water is improved. The exhaust steam that has done work in the turbine 3 is condensed in the condenser 5. The condensed high-temperature geothermal water passes through the air preheater 6, the heat network heat exchanger 7 and the heat pipe heat exchanger 8 in sequence, and finally flows into the fishpond 15.

[0045] In the above case, the gas processing assembly 19 includes a carbon dioxide regeneration tower 191 connected to the carbon dioxide absorption tower 18, the carbon dioxide regeneration tower 191 connected to the carbon dioxide storage tank 192, the carbon dioxide storage tank 192 connected to the pyrolysis furnace 24, and a blower 28 provided between the carbon dioxide storage tank 192 and the pyrolysis furnace 24.

[0046] Understandably, the adsorbent in the carbon dioxide absorption tower 18 absorbs carbon dioxide from the biogas, and then the adsorbent that has absorbed carbon dioxide is transferred to the carbon dioxide regeneration tower 191. The reducing agent in the carbon dioxide regeneration tower 191 replaces the carbon dioxide in the adsorbent and stores it in the carbon dioxide storage tank 192. When the pyrolysis furnace 24 needs to pyrolyze, the carbon dioxide gas stored in the carbon dioxide storage tank 192 is introduced into the pyrolysis furnace 24 by the blower 28 as an inert atmosphere for the pyrolysis furnace 24, which can improve the bio-oil yield and reduce the cost of inert gas preparation.

[0047] Furthermore, a methane storage tank 29 and an air pump 30 are provided between the carbon dioxide absorption tower 18 and the internal combustion engine 20. The carbon dioxide absorption tower 18 is connected to the methane storage tank 29, the methane storage tank 29 is connected to the air pump 30, and the air pump 30 is connected to the second induced draft fan 31 and the internal combustion engine 20 through a three-way valve 26. The second induced draft fan 31 is connected to the air preheater 6.

[0048] It should be noted that the methane storage tank 29 stores the gas treated by the carbon dioxide absorption tower 18. When the internal combustion engine 20 needs to burn, the methane in the methane storage tank 29 is extracted by the air pump 30 and transported to the internal combustion engine 20 through the three-way valve 26. The oxygen supplied by the greenhouse 27 to the air preheater 6 is introduced into the internal combustion engine 20 through the three-way valve 26 by the second induced draft fan 31, so that the methane and oxygen can burn in the internal combustion engine 20 to drive the second generator 21 to generate electricity.

[0049] In the above embodiment, a three-way valve 26 is provided on the pipeline connecting the greenhouse 27 to the air preheater 6 and the fishpond 15. The first port of the three-way valve 26 is connected to the greenhouse 27, the second port of the three-way valve 26 is connected to the air preheater 6, and the third port of the three-way valve 26 is connected to the fishpond 15.

[0050] Understandably, some of the oxygen-rich air produced by the plants in the greenhouse 27 is introduced into the internal combustion engine 20 through the three-way valve 26, which can promote the combustion of methane, improve the combustion efficiency of the internal combustion engine 20, and reduce the generation of harmful gases. The other part is introduced into the fishpond 15 through the three-way valve 26 to oxygenate the fishpond 15.

[0051] In winter, the cold weather causes the water level in fishpond 15 to drop, and the surface is prone to freezing and being covered by ice and snow. Over time, this leads to oxygen depletion, causing the fish in fishpond 15 to die from lack of oxygen. Providing oxygen produced by photosynthesis in the plants inside greenhouse 27 to fishpond 15 can prevent oxygen depletion and thus save the fish from dying from oxygen deficiency.

[0052] Furthermore, the high-temperature mixed gas after pyrolysis in the pyrolysis furnace 24 and the high-temperature flue gas generated by the internal combustion engine 20 enter the baking device 23 under the action of the first induced draft fan 25. After mixing, the mixture passes through the heat exchanger 9 and the heater, and undergoes multiple heat exchanges and cooling processes, which can serve as the atmosphere for plant photosynthesis in the greenhouse 27.

[0053] Based on the above embodiments, the pyrolysis furnace 24 is connected to the bio-oil storage tank 32 and the biochar recovery tank 33 respectively.

[0054] It should be noted that the bio-oil produced after pyrolysis in pyrolysis furnace 24 is collected in bio-oil storage tank 32, and the biochar produced is collected in biochar recovery tank 33.

[0055] In the above embodiment, a screw pump 34 for controlling the feeding of materials from the slurry tank 16 to the biogas digester 11 is provided on the pipeline connecting the slurry tank 16 and the biogas digester 11.

[0056] Understandably, after the biogas feedstock is uniformly stirred in the homogenizing tank, it is transported to the biogas digester 11 via screw pump 34. The biogas produced in the biogas digester 11 passes through the desulfurization tower 17 and the carbon dioxide absorption tower 18. The resulting carbon dioxide-rich liquid enters the carbon dioxide regeneration tower 191 and is stored in the carbon dioxide storage tank 192. It is then connected to the pyrolysis furnace 24 via blower 28 to provide inert gas for the pyrolysis in the pyrolysis furnace 24. The generated fuel gas, under the action of gas pump 30, enters the internal combustion engine 20 through the three-way valve 26 to provide fuel gas for the combustion in the internal combustion engine 20, thereby driving the first generator 4 to generate electricity. The pyrolysis furnace 24 and the internal combustion engine 20 produce... The high-temperature flue gas generated passes sequentially through the baking device 23, superheater 9, evaporator 10, and greenhouse 27 under the action of the first induced draft fan 25. The gas after heat exchange and cooling can be used as the atmosphere for photosynthesis of plants in greenhouse 27. The oxygen-rich gas produced by photosynthesis of plants in greenhouse 27 enters the air preheater 6 and fishpond 15 through the three-way valve 26 to supply oxygen to the fish in fishpond 15 and prevent the fish in fishpond 15 from dying due to lack of oxygen in winter. The oxygen entering the air preheater 6 is introduced into the internal combustion engine 20 under the action of the second induced draft fan to supply oxygen for combustion in internal combustion engine 20 and improve the combustion efficiency of internal combustion engine 20.

[0057] Among them, the screw pump 34 is characterized by stable flow, small pressure pulsation, self-priming capability, low noise, high efficiency, long service life, and reliable operation. Its outstanding advantage is that it does not form eddies when conveying media, is not sensitive to the viscosity of the media, and can convey high viscosity media.

[0058] As a preferred embodiment, the raw materials for the uniform mixing tank 16 include organic domestic waste, human and animal excrement, and sludge from the fishpond 15 generated by the residential area 13 and the breeding farm 14. The biomass pyrolysis raw materials for the pyrolysis furnace 24 are straw, rice husks, etc. produced by the farmland 22 and biogas residue and biogas slurry after fermentation in the biogas digester 11.

[0059] It should be noted that the biogas feedstock includes organic domestic waste, human and animal excrement, and sludge from fishponds 15 generated in residential areas 13 and livestock farms 14; the biomass pyrolysis feedstock includes straw and rice husks from farmland 22 and biogas residue and biogas slurry from biogas digesters 11. Among these, human and animal excrement and wastewater sludge from various agricultural activity sites are used as fermentation feedstocks. The fermented biogas slurry and biogas residue have complex chemical compositions, unstable components, and variable thermal properties. Therefore, it is necessary to overcome unavoidable problems such as evaporation and oxidation to improve energy conversion efficiency. Therefore, after mixing biogas residue and biogas slurry with agricultural and forestry biomass, they are fed into pyrolysis furnace 24 for pyrolysis treatment. This not only solves the problems of easy evaporation and oxidation of biogas residue and biogas slurry, but also obtains biomass fuel with higher calorific value, improving its energy utilization efficiency. Moreover, the biochar produced has high stability and is easier to store. The biochar can be directly used in farmland 22 and greenhouses 27 to increase the organic carbon content of the soil and regulate the soil's water retention capacity.

[0060] In the above situation, the first generator 4 and the second generator 21 are used to supply power to the breeding farm 14, the greenhouse 27, the fish pond 15, the pyrolysis furnace 24 and the residential area 13.

[0061] Understandably, the electricity generated by the first generator 4 and the second generator 21 is used not only for agricultural production sites such as the breeding farm 14, greenhouse 27, fish pond 15, and pyrolysis furnace 24, but also for the surrounding residential area 13.

[0062] Figure 2 shows the working method of a rural energy integrated utilization system. Applied to the aforementioned rural energy integrated utilization system, the working method includes:

[0063] Step S1: The high-temperature geothermal water in the geothermal well 1 is extracted by the water pump 201. The saturated steam from the first flash evaporator 202 passes through the heat exchanger 9 and enters the high-pressure cylinder of the turbine 3 to expand and do work, driving the first generator 4 to generate electricity. The saturated water from the first flash evaporator 202 passes through the evaporator 10 and enters the low-pressure cylinder of the turbine 3 to expand and do work, driving the first generator 4 to generate electricity. The exhaust steam after doing work is condensed in the condenser 5. The condensed high-temperature geothermal water passes through the air preheater 6, the heat network heat exchanger 7 and the heat pipe heat exchanger 8 in sequence, and finally flows into the fishpond 15.

[0064] Step S2: The biogas raw material in the homogenization tank is pumped into the biogas digester 11 by the screw pump 34 and fermented in the biogas digester 11. The biogas produced passes through the desulfurization tower 17 and the carbon dioxide absorption tower 18 in sequence. The generated carbon dioxide-rich liquid enters the carbon dioxide regeneration tower 191. After carbon dioxide regeneration, it is stored in the carbon dioxide storage tank 192 and introduced into the pyrolysis furnace 24 by the blower 28. The generated methane is pumped into the internal combustion engine 20 by the gas pump 30.

[0065] Step S3: The straw and rice husks produced by farmland 22 are mixed with the biogas residue and biogas slurry produced by biogas digester 11 and fed into baking device 23 as biomass pyrolysis raw materials. After baking pretreatment, the mixture is pyrolyzed in pyrolysis furnace 24. The high-temperature carbon dioxide gas produced by pyrolysis furnace 24 and the high-temperature flue gas produced by internal combustion engine 20 enter baking device 23 under the action of second induced draft fan 31. The mixed gas from baking device 23 passes through heater 9 and evaporator 10 for heat exchange. The low-temperature mixed gas after heat exchange flows into greenhouse 27 to promote plant photosynthesis. The oxygen-rich air produced by plant photosynthesis enters fish pond 15 and internal combustion engine 20 respectively, oxygenating fish pond 15 and providing oxygen for the combustion of methane in internal combustion engine 20. The combustion of internal combustion engine 20 drives second generator 21 to generate electricity.

[0066] It should be noted that high-temperature geothermal water is extracted from geothermal well 1 by water pump 201, flashes in the first flash steam, and the resulting saturated steam enters superheater 9, where it absorbs the waste heat from the exhaust gas of internal combustion engine 20 and becomes superheated steam, which then expands and does work in the high-pressure cylinder of turbine 3. The resulting saturated water enters the second flash evaporator 203 for flashing again, and absorbs the waste heat from the exhaust gas of internal combustion engine 20 in the heater, becoming low-pressure high-temperature steam, which then expands and does work in the low-pressure cylinder of turbine 3. The exhaust steam that has done work enters condenser 5, where, due to its high temperature (generally 90℃), the released heat can be transported over long distances for use in rural residential heating or hot water supply during winter. High-temperature geothermal water (generally 70℃) heats oxygen-enriched air in air preheater 6, then enters heat exchanger 7 for heat exchange (generally 55℃). The heat exchanged is used to heat the aquaculture farm 14. The geothermal water after heat exchange (generally 40℃) enters heat pipe heat exchanger 8 and heats biogas digester 11 through gravity heat pipe 12. The biogas fermentation temperature is generally controlled at 28-38℃. Due to the uniform temperature of gravity heat pipe 12, the temperature difference inside biogas digester 11 can be reduced. Finally, the geothermal tailwater (generally 10-20℃) is discharged into fishpond 15 to protect fish fry overwintering, improve survival rate, and reduce costs.

[0067] The temperatures mentioned above are only the specific values ​​of the temperatures in this application. In actual applications, there are no restrictions on the specific values ​​of the temperatures. This is only to make it easier and more intuitive to understand how this cascade utilization scheme can improve the utilization efficiency of geothermal water.

[0068] Organic household waste, human and animal excrement, sludge, and other biogas feedstocks are stirred and homogenized in a homogenizing tank, and then pumped into biogas digester 11 by screw pump 34 for constant-temperature fermentation. The main components of the fermentation gas are methane and carbon dioxide. The biogas produced is desulfurized in desulfurization tower 17 and then enters carbon dioxide absorption tower 18. The resulting carbon dioxide-rich liquid enters carbon dioxide regeneration tower 191 to decompose into carbon dioxide gas and water. The carbon dioxide gas is collected by carbon dioxide storage tank and driven by blower 28 into pyrolysis furnace 24 to provide an inert atmosphere for pyrolysis. The generated fuel gas (mainly methane) is stored in methane storage tank 29. When power generation is needed, three-way valve 26 is opened, and methane enters internal combustion engine 20 under the action of air pump 30. At the same time, in order to improve the combustion efficiency of biogas, air preheater 6 is used to heat the greenhouse. The oxygen-rich air produced by plant photosynthesis in greenhouse 27 is fed into internal combustion engine 20 by a second induced draft fan 31 and mixed with methane for combustion. The high-temperature flue gas produced by combustion (generally 400-500℃) and high-temperature carbon dioxide gas produced by pyrolysis furnace 24 are fed into baking device 23 by a first induced draft fan 25, raising the temperature for biomass baking to a suitable level (generally 300℃). The mixed gas exiting baking device 23 passes through superheater 9 and heater for heat exchange to heat geothermal water and improve its power generation efficiency. The cooled mixed gas after heat exchange flows into greenhouse 27 to promote plant photovoltaic activity. A portion of the oxygen-rich air produced by the plants in greenhouse 27 is fed into internal combustion engine 20 for combustion with methane, while the other portion is circulated into fishpond 15 to oxygenate it. This scheme coordinates the gases generated in each part of the system to achieve gas recycling and improve gas utilization efficiency.

[0069] The biogas residue and slurry produced by biogas digester 11 are mixed with straw, rice husks, etc. from farmland 22 and fed into baking device 23 as biomass pyrolysis raw materials. The baking process reduces the water content of biomass, damages the lignocellulose structure to a certain extent, and significantly increases the content of phenolic products, which is beneficial to improving the quality of bio-oil. The biomass raw materials that have undergone baking pretreatment are pyrolyzed in pyrolysis furnace 24, and the resulting bio-oil is stored in bio-oil storage tank 32 and can be used for combustion heating, power generation, fuel oil and chemical production. The biochar produced can be directly used in farmland 22. Its rich organic carbon content can increase the organic carbon content of the soil, and its certain amount of mineral nutrients can increase the phosphorus, potassium, calcium, magnesium and nitrogen in the soil. The rich porosity can significantly regulate the soil's water holding capacity. It can also be used in animal feed in farms 14 and fish ponds 15 to improve the digestion and metabolism of nutrients by animals and improve their production performance.

[0070] In summary, the rural energy integrated utilization system provided by this invention rationally combines geothermal energy and biomass energy with rural production and daily life. It recovers and utilizes the waste heat from high-temperature geothermal tailwater and biogas power generation tail gas. The geothermal energy utilization system and the biomass utilization system complement each other and have complementary advantages, realizing the cascade utilization of energy, meeting the local residents' heat and electricity needs, and improving the economic efficiency of agricultural production.

[0071] The proposed scheme aims to strengthen the integration of modern agriculture and energy systems, coordinate rural energy supply systems, recycle and utilize agricultural and forestry biomass, human and animal waste, and combine this with the cascade utilization of geothermal resources to enhance the economic and environmental benefits of agricultural activities, promote sustainable rural development, and provide strong support for my country's "dual carbon" goals.

[0072] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0073] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0074] The above provides a detailed description of a rural energy comprehensive utilization system and its working method provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A rural energy integrated utilization system, characterized in that, This includes geothermal energy utilization systems and biomass energy utilization systems; The geothermal energy utilization system includes a geothermal well (1), which is connected in sequence to a geothermal water treatment component (2), a steam turbine (3), a first generator (4), a condenser (5), an air preheater (6), a heat network heat exchanger (7), and a heat pipe heat exchanger (8). The geothermal water treatment component (2) is connected to a superheater (9) and an evaporator (10). The superheater (9) and the evaporator (10) are both connected to the steam turbine (3). The heat pipe heat exchanger (8) is equipped with a gravity heat pipe (12) for transferring heat to the biogas digester (11). The condenser (5) is used to provide heating or hot water to the residential area (13). The heat network heat exchanger (7) is used to provide heating to the aquaculture farm (14). The hot water after heat exchange by the heat pipe heat exchanger (8) is supplied to the fishpond (15). The biomass energy utilization system includes a biomass fermentation system and a biomass pyrolysis system; The biomass fermentation system includes a uniform mixing tank (16) connected to the biogas digester (11), the biogas digester (11) is connected in sequence to a desulfurization tower (17) and a carbon dioxide absorption tower (18), the carbon dioxide absorption tower (18) is connected to a gas treatment component (19) and an internal combustion engine (20), and the internal combustion engine (20) is connected to a second generator (21). The biomass pyrolysis system includes a baking device (23) and a pyrolysis furnace (24) connected in sequence. The baking device (23) is used to preheat the straw and rice husks produced by the farmland (22). The pyrolysis furnace (24) is connected to the gas treatment component (19). The first induced draft fan (25) is connected to the output end of the internal combustion engine (20) and the pyrolysis furnace (24) through a three-way valve (26). The first induced draft fan (25) is connected to the baking device (23). The baking device (23) is connected in sequence to the superheater (9), the evaporator (10), and the greenhouse (27). The greenhouse (27) is connected to the air preheater (6) and the fishpond (15) respectively. The air preheater (6) is connected to the internal combustion engine (20).

2. The rural energy comprehensive utilization system according to claim 1, characterized in that, The geothermal water treatment assembly (2) includes a water pump (201) connected to the geothermal well (1) and a first flash evaporator (202) connected to the water pump (201). The first flash evaporator (202) is connected to the superheater (9) and a second flash evaporator (203) respectively, and the second flash evaporator (203) is connected to the evaporator (10).

3. The rural energy comprehensive utilization system according to claim 2, characterized in that, The gas processing assembly (19) includes a carbon dioxide regeneration tower (191) connected to the carbon dioxide absorption tower (18), the carbon dioxide regeneration tower (191) being connected to a carbon dioxide storage tank (192), the carbon dioxide storage tank (192) being connected to the pyrolysis furnace (24), and a blower (28) being provided between the carbon dioxide storage tank (192) and the pyrolysis furnace (24).

4. The rural energy comprehensive utilization system according to claim 3, characterized in that, A methane storage tank (29) and an air pump (30) are provided between the carbon dioxide absorption tower (18) and the internal combustion engine (20). The carbon dioxide absorption tower (18) is connected to the methane storage tank (29), and the methane storage tank (29) is connected to the air pump (30). The air pump (30) is connected to the second induced draft fan (31) and the internal combustion engine (20) through the three-way valve (26). The second induced draft fan (31) is connected to the air preheater (6).

5. The rural energy comprehensive utilization system according to claim 4, characterized in that, The three-way valve (26) is provided on the pipeline connecting the greenhouse (27) to the air preheater (6) and the fishpond (15). The first port of the three-way valve (26) is connected to the greenhouse (27), the second port of the three-way valve (26) is connected to the air preheater (6), and the third port of the three-way valve (26) is connected to the fishpond (15).

6. The rural energy comprehensive utilization system according to claim 5, characterized in that, The pyrolysis furnace (24) is connected to the bio-oil storage tank (32) and the biochar recovery tank (33), respectively.

7. The rural energy comprehensive utilization system according to claim 6, characterized in that, A screw pump (34) for controlling the feeding of material from the slurry tank (16) to the biogas digester (11) is provided on the pipeline connecting the slurry tank (16) and the biogas digester (11).

8. The rural energy comprehensive utilization system according to claim 7, characterized in that, The raw materials of the uniform mixing tank (16) include organic domestic waste, human and animal excrement and sludge from the residential area (13) and the breeding farm (14), and the biomass pyrolysis raw materials of the pyrolysis furnace (24) are straw and rice husks produced from the farmland (22) and biogas residue and biogas slurry after fermentation in the biogas digester (11).

9. The rural energy comprehensive utilization system according to claim 8, characterized in that, The first generator (4) and the second generator (21) are used to supply power to the residential area (13), the breeding farm (14), the fish pond (15), the pyrolysis furnace (24) and the greenhouse (27).

10. A working method for a rural energy integrated utilization system, characterized in that, The rural energy comprehensive utilization system described in claim 9, wherein the working method of the rural energy comprehensive utilization system includes: High-temperature geothermal water in the geothermal well (1) is pumped out by a water pump (201). Saturated steam from the first flash evaporator (202) passes through the heat exchanger (9) and enters the high-pressure cylinder of the turbine (3) to expand and do work, driving the first generator (4) to generate electricity. Saturated water from the first flash evaporator (202) passes through the evaporator (10) and enters the low-pressure cylinder of the turbine (3) to expand and do work, driving the first generator (4) to generate electricity. The exhaust steam that has done work is condensed in the condenser (5). The condensed high-temperature geothermal water passes through the air preheater (6), the heat network heat exchanger (7), and the heat pipe heat exchanger (8) in sequence, and finally flows into the fishpond (15). The biogas feedstock in the homogenizing tank (16) is pumped into the biogas digester (11) by the screw pump (34), fermented in the biogas digester (11), and the biogas produced passes through the desulfurization tower (17) and the carbon dioxide absorption tower (18) in sequence. The generated carbon dioxide-rich liquid enters the carbon dioxide regeneration tower (191), and the carbon dioxide is stored in the carbon dioxide storage tank (192) after regeneration. It is then introduced into the pyrolysis furnace (24) by the blower (28). The generated methane is pumped into the internal combustion engine (20) by the gas pump (30). Straw and rice husks produced in farmland (22) are mixed with biogas residue and biogas slurry produced in biogas digester (11) and fed into baking device (23) as raw materials for biomass pyrolysis. After baking pretreatment, the mixture is pyrolyzed in pyrolysis furnace (24). High-temperature carbon dioxide gas produced in pyrolysis furnace (24) and high-temperature flue gas produced in internal combustion engine (20) enter baking device (23) under the action of second induced draft fan (31). The mixed gas from baking device (23) passes through superheater (9) and evaporator (10) for heat exchange. The low-temperature mixed gas after heat exchange flows into greenhouse (27) to promote plant photosynthesis. The oxygen-rich air produced by plant photosynthesis enters fish pond (15) and internal combustion engine (20) respectively to oxygenate fish pond (15) and provide oxygen for methane combustion in internal combustion engine (20). Combustion of internal combustion engine (20) drives second generator (21) to generate electricity.

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