Clean and low-carbon heating system in winter in cold region using agricultural and livestock waste fermentation heat as energy

Abstract

This invention proposes a clean and low-carbon winter heating system for cold regions, utilizing the fermentation heat of agricultural and livestock waste as energy, belonging to the field of clean and low-carbon heating. It solves the problems of heating pollution in northern winters and the difficulty in cleanly treating agricultural and livestock waste. This invention employs an intermittent fermentation heat utilization mode, with a heat utilization efficiency greater than 60%. The aerobic fermentation process is both a production and energy consumption process. Excessive heat discharged from the system with moist steam can cause the fermentation system temperature to drop too low, affecting the production process. By intermittently extracting and venting steam, the rate at which the system controls the heat carried away by the moist steam can be controlled, ensuring sufficient energy consumption for the system itself, thereby ensuring the stability of the indoor heating energy source and improving the utilization rate of heat energy. This invention has a simple structure, conforms to building configurations, is easy to operate, and can be widely promoted.

Description

Technical Field

[0001] This invention belongs to the field of clean and low-carbon heating, and in particular relates to a clean and low-carbon heating system for cold regions in winter that uses the fermentation heat of agricultural and livestock waste as energy. Background Technology

[0002] In northern my country, winter temperatures generally drop below freezing, especially in the Northeast where temperatures often remain below -15°C, resulting in a huge demand for heating. Currently, scattered coal burning is the primary method of winter heating in rural northern China. To achieve clean heating and reduce carbon emissions, there is a need to develop clean heat sources that are sustainable, stable, easy to operate, and low-cost.

[0003] On the other hand, my country's annual production of biomass solid waste exceeds 5 billion tons, equivalent to 2.5 billion tons of standard coal. Crop straw production reaches 800-900 million tons, with corn straw accounting for the largest share at approximately 32.5%, and corn production in northern regions accounting for 75%. In addition, my country produces as much as 3.05 billion tons of livestock manure annually.

[0004] Biomass aerobic fermentation heat generation technology is a technique that uses microorganisms to catalytically degrade organic matter under aerobic conditions, producing water, CO2, and solid fermentation products (organic fertilizer, cattle bedding, and feed, etc.), releasing chemical energy as heat. In conventional composting, approximately 60%–70% of the chemical energy in biomass is converted into heat, while only 30%–40% is retained in the fertilizer. Studies have found that large-scale fermentation systems can provide heat sources above 50°C for several months during aerobic fermentation. If the heat released from waste agricultural and livestock solid waste can replace the combustion of fossil fuels to supplement the heat needed for winter heating in northern regions, it would be a highly efficient solution to meet the dual needs of "clean winter heating in northern rural areas" and "clean treatment of agricultural and livestock waste."

[0005] Currently, scholars mainly focus on the efficient conversion of compost raw materials and the improvement of compost efficiency, while paying less attention to the heat generation during the fermentation process. Furthermore, the temperature of bio-fermentation heat is generally below 70℃, and the bio-fermentation process both generates and utilizes heat, making it complex. Therefore, there is a lack of related technologies and equipment for the recovery and utilization of heat from straw fermentation on the market.

[0006] Current research on heat recovery equipment for aerobic fermentation faces a series of problems, including low heat utilization efficiency and an imbalance between heat production and consumption. Most existing technologies only recover latent or sensible heat. Even those technologies that utilize both sensible and latent heat during fermentation still suffer from low heat utilization efficiency. Therefore, it is necessary to develop heat recovery systems with efficient utilization methods and high heat recovery efficiency.

[0007] Meanwhile, in the cold northern regions, the outside temperature is extremely low, resulting in even greater heat loss through heat conduction. Therefore, the insulation requirements for fermentation heat recovery systems are extremely stringent. Conventional heat recovery processes and equipment are insufficient to withstand the low external temperatures, necessitating the development and design of a comprehensive, efficient, and rigorously insulated heat recovery system.

[0008] Developing a novel fermentation heat recovery system using agricultural and livestock waste as raw materials for heating in northern regions is of great significance for fully utilizing biomass resources such as straw and addressing the urgent need for clean energy. Summary of the Invention

[0009] In view of this, the present invention aims to propose a clean and low-carbon heating system for cold regions in winter that uses the heat from the fermentation of agricultural and livestock waste as energy, which can simultaneously solve the problems of heating pollution in northern winters and the difficulty in cleaning and disposing of agricultural and livestock waste.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: a clean and low-carbon heating system for cold regions in winter that uses the heat from the fermentation of agricultural and livestock waste as energy, comprising a fermentation chamber and a heat extraction room, wherein a heat transfer wall separates the fermentation chamber and the heat extraction room.

[0011] The fermentation chamber includes a chamber body, an exhaust device, a ventilation pipe, a porous suction pipe, and a spraying device. The chamber body contains a fermentation pile. An exhaust device is installed on the side wall of the chamber body above the fermentation pile. A ventilation pipe is installed at the bottom, and a porous suction pipe and a spraying device are installed at the top.

[0012] The heat exchange chamber includes a steam-water heat exchanger, a water storage tank, an air heat exchanger, and a liquid collection tank. The liquid collection tank is connected to the steam-water heat exchanger and the air heat exchanger to collect the condensate generated during the heat exchange process. The condensate is pumped into the fermentation chamber via a spray device to replenish the moisture in the fermentation pile. One end of the air heat exchanger is connected to the outside atmosphere, with an induced draft fan installed between them, and the other end is connected to the ventilation pipe inside the fermentation chamber. One end of the steam-water heat exchanger is connected to a porous suction pipe, with a pipe exhaust fan installed between them, and the other end is connected to the air heat exchanger. One end of the water storage tank is connected to the steam-water heat exchanger, and the other end is connected to the heating area. The side with the larger side area is against the wall to utilize the heat conducted by the fermentation chamber for insulation.

[0013] Furthermore, the fermentation chamber and heating room are surrounded by an insulation layer, with the overall heat transfer coefficient controlled at 0.25–0.35 W / (m²). 2 ·K).

[0014] Furthermore, the fermentation chamber is equipped with a spare ventilation hole at the top of the chamber.

[0015] Furthermore, the hot steam inlet temperature of the steam-water heat exchanger is 60℃~70℃, and the hot gas outlet temperature drops to below 45℃ after one heat exchange, and the hot gas outlet temperature drops to below 30℃ after heat exchange through the air heat exchanger.

[0016] Furthermore, the cold water inlet temperature of the steam-water heat exchanger is 5-10℃, the circulating water inlet temperature is 20-30℃, and the outlet water temperature is 40-50℃.

[0017] Furthermore, the cold air inlet temperature of the air heat exchanger is -20 to 10°C. The lower the temperature, the more obvious the heating effect. After heat exchange, the cold air outlet temperature can reach 20°C to 30°C.

[0018] Furthermore, under the action of the pipe air pump, the humid and hot air generated by the stack is introduced into the steam-water heat exchanger and cold water through the steam inlet pipe for heat exchange. The condensate generated during the heat exchange flows out of the steam-water heat exchanger under the action of airflow and gravity, and is separated and collected through the drain valve.

[0019] Furthermore, the system uses tap water as the medium for heat storage. The cold water is softened and stored in a water tank. Under the action of the water pump, it flows into the steam-water heat exchanger for heat exchange. The temperature of the warm water obtained after heat exchange reaches 38-50℃, which can be used directly as domestic water or sent to the heating area for heating. After heating, it is circulated back to the water tank.

[0020] A clean and low-carbon heating method for cold regions in winter that uses fermentation heat from agricultural and livestock waste as energy includes aerobic fermentation heat generation and fermentation heat utilization processes.

[0021] (1) Aerobic fermentation heat production includes the following steps:

[0022] Step 1: Process the cellulosic biomass using a crusher or cutter, and mix the processed straw with livestock manure such as cow dung evenly to make the carbon-nitrogen ratio of the material 25-50. Then, spread a layer of processed organic material with a thickness of 20-50cm in the fermentation chamber using a material cart.

[0023] Step 2: Evenly sprinkle bran, inoculant, auxiliary materials and spray water on top of the material. The bran accounts for 0-5% of the material mass, the fermentation inoculant accounts for 0-0.2%, and a small amount of quicklime and superphosphate and other auxiliary materials are added, accounting for 0-1.5%. Water is added to control the moisture content of the material at 60-65%.

[0024] Step 3: Continue adding materials and repeat the above process. Close the multiple doors of the fermentation chamber layer by layer according to the height of the material pile until the required fermentation scale is reached. Close the outer insulation door to seal the chamber and start fermentation to generate heat.

[0025] (2) The utilization of fermentation heat includes the following steps:

[0026] Step 4: During the high-temperature fermentation period, the hot and humid steam generated in the fermentation chamber is extracted using a pipe exhaust fan. It is first introduced into a steam-water heat exchanger to exchange heat with cold water to obtain warm water for heating. Then it is introduced into an air heat exchanger to exchange heat with fresh air to obtain hot air for oxygen supply. The steam extraction and ventilation oxygen supply process is carried out intermittently.

[0027] Step 5: Soften the cold water beforehand and store it in a water storage tank. While steam is being extracted, the cold water is passed through a steam-water heat exchanger to obtain usable warm water. This warm water is then sent to the heating area for heat utilization; the water flow rate is set to 0.2–1.5 m³ / h. 3 At a rate of / h, water circulates between the steam-water heat exchanger and the heating area for uninterrupted heat extraction and utilization. When the high-flow steam extraction process stops, the water temperature gradually decreases; when the temperature inside the fermentation chamber rises back to 60-70℃, at which point the circulating water temperature is relatively low, high-flow steam extraction, ventilation, and heat recovery are resumed, and this cycle repeats continuously.

[0028] Furthermore, in step 1, the cellulose biomass is processed by a pulverizer or cutter to obtain small segments of 3-10 cm.

[0029] Furthermore, in step 4, during the steam extraction and ventilation process, the steam extraction flow rate of the pipeline exhaust fan is adjusted to 60–300 m³ / h based on the fermentation chamber volume and heat demand. 3 / h, the ventilation flow rate of the induced draft fan is adjusted to 30~180m³ / h. 3 When the temperature inside the warehouse drops to 50-60℃, stop high-flow steam extraction and ventilation, and adjust the steam extraction and ventilation flow rates to 0-50m³ / h. 3 / h, heat gradually accumulates in the fermentation chamber, and the temperature slowly rises.

[0030] Compared with existing technologies, the beneficial effects of the clean and low-carbon winter heating system for cold regions that uses the fermentation heat of agricultural and livestock waste as an energy source, as described in this invention, are:

[0031] 1. This invention adopts an intermittent fermentation heat utilization mode with a heat utilization efficiency of more than 60%. The aerobic fermentation process is both a production process and an energy consumption process. Excessive heat discharged from the system with humid steam will cause the fermentation system temperature to drop too low, affecting the production process. By intermittently extracting steam and ventilating, the rate at which the system controls the heat carried away by the humid steam can be controlled, ensuring sufficient energy consumption of the system itself, thereby ensuring the stability of the indoor heating energy source, and improving the utilization rate of heat energy.

[0032] 2. This invention uses the heat energy released from discarded agricultural and livestock solid waste to replace the combustion of fossil fuels, supplementing the heat required for winter heating in northern regions. It can be applied to various rural settings, including vegetable greenhouses, livestock farms, and farmhouses, effectively alleviating the serious air pollution problem caused by the burning of scattered coal. It also proposes a localized utilization scheme for agricultural and livestock solid organic waste.

[0033] 3. This invention utilizes aerobic fermentation of agricultural and livestock organic waste such as straw and poultry manure. The solid compost produced after fermentation has very high nutrient content, meets the standards for biological organic fertilizer, and can be returned to the field as organic fertilizer. This achieves the clean treatment of agricultural waste and poultry manure and the recycling of biomass energy, while also contributing to carbon emission reduction.

[0034] 4. This invention enables heating from waste biomass resources in northern regions, providing a strict insulation design scheme for fermentation heating reactors in cold areas, significantly reducing heat loss caused by the external environment and ensuring normal operation of the system.

[0035] 5. The present invention has a simple structure, is house-shaped, is easy to operate, and can be promoted on a large scale. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0037] Figure 1 This is a schematic diagram showing the distribution of the ventilation pipes at the bottom of the fermentation chamber according to the present invention;

[0038] Figure 2 This is a schematic diagram of the structure of the heat extraction room described in this invention;

[0039] Figure 3 This is a schematic diagram of the porous suction tube described in this invention;

[0040] Figure 4 This is a schematic diagram of the process flow for implementing the system described in this invention;

[0041] Figure 5 This is a schematic diagram of the fermentation chamber described in this invention.

[0042] In the diagram: 1-Spare vent; 2-Water supply pipe; 3-Porous suction pipe; 4-Steam inlet pipe; 5-Pipe exhaust fan; 6-Steam-water heat exchanger; 7-Support frame; 8-Liquid collection tank; 9-Air heat exchanger drain pipe; 10-Air heat exchanger; 11-Fresh air outlet pipe; 12-External water supply pipe; 13-Water storage tank; 14-Heating water pipe; 15-Drain valve; 16-Insulation layer; 17-Heating water return pipe; 18-Exhaust device; 19-Fermentation pile; 20-Ventilation pipe; 21-Support rod; 22-Spraying device; 23-Fresh air inlet pipe; 24-Filter device; 25-Waste gas exhaust pipe; 26-Exhaust fan; 27-Water pump; 28-Fermentation chamber; 29-Heat extraction room; 30-Heating area; 31-Fermentation chamber multi-layer door; 32-Heat extraction room door. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0044] See Figure 1-5 This embodiment describes a clean and low-carbon winter heating system for cold regions that uses the heat from the fermentation of agricultural and livestock waste as an energy source. The system is designed as a house structure, consisting of a fermentation chamber 28 and a heating room 29. A heat-transferring wall separates the fermentation chamber 28 and the heating room 29, allowing heat from the fermentation chamber 28 to be transferred to the heating room 29.

[0045] The fermentation chamber 28 has a large volume and is used for aerobic fermentation and heat generation of organic materials. It mainly includes an exhaust device 18, a fermentation pile 19, an air vent 20 below it, a porous air intake pipe 3 above it, and a spray device 22. The fermentation pile 19 is installed inside the chamber. The exhaust device 18 is installed on the side wall of the chamber above the fermentation pile 19. The air vent 20 is set at the bottom, and the porous air intake pipe 3 and spray device 22 are set at the top.

[0046] The heat exchange room 29 houses the equipment used in the heat exchange process, mainly including a steam-water heat exchanger 6, a water storage tank 13, an air heat exchanger 10, and a liquid collection tank 8. The liquid collection tank 8 is connected to the steam-water heat exchanger 6 and the air heat exchanger 10, collecting the condensate generated during the heat exchange process. The condensate is pumped by a water pump 27 into a spray device 22 and then into the fermentation chamber 28 to replenish the moisture in the fermentation pile 19. One end of the air heat exchanger 10 is connected to the outside atmosphere, with an induced draft fan 26 installed between it and the other end connected to a ventilation pipe 20 inside the fermentation chamber 28. One end of the steam-water heat exchanger 6 is connected to a porous suction pipe 3, with a pipe exhaust fan 5 installed between it and the other end connected to the air heat exchanger 10. One end of the water storage tank 13 is connected to the steam-water heat exchanger 6, and the other end is connected to the heating area 30. The side with the larger side area is against the wall and insulated using the heat conducted by the fermentation chamber 28.

[0047] This invention separates the heat exchange equipment and places it in the heat extraction room 29 for easy maintenance and to facilitate the feeding of materials into the fermentation chamber 28. The heat emitted by the fermentation pile 19 can be conducted to the heat extraction room 29 through the intermediate partition wall to maintain the temperature of the heat extraction room 29 and reduce heat loss.

[0048] The hot steam inlet temperature of the steam-water heat exchanger 6 is 60℃~70℃. After one heat exchange, the hot steam outlet temperature drops to below 45℃. After heat exchange in the air heat exchanger 10, the hot steam outlet temperature drops to below 30℃. The cold water inlet temperature of the steam-water heat exchanger 6 is 5~10℃, the circulating water inlet temperature is 20~30℃, and the outlet water temperature is 40~50℃.

[0049] The air heat exchanger 10 has a cold air inlet temperature of -20 to 10℃. The lower the temperature, the more obvious the heating effect. After heat exchange, the cold air outlet temperature can reach 20℃ to 30℃.

[0050] The fermentation chamber 28 and the heating room 29 are surrounded by insulating material, with the overall heat transfer coefficient controlled at 0.25–0.35 W / (m²). 2 ·K).

[0051] The roof of the fermentation chamber 28 is equipped with a spare ventilation hole 1. Under normal operation, the spare ventilation hole 1 is closed. The inner diameter of the spare ventilation hole 1 is 10-20cm, and the end is connected to a bend that slopes downward to prevent rain and snow from entering.

[0052] A clean and low-carbon winter heating method for cold regions that uses the fermentation heat of agricultural and livestock waste as energy includes aerobic fermentation heat generation and fermentation heat utilization processes.

[0053] (1) Aerobic fermentation heat production includes the following steps:

[0054] Step 1: Process cellulose biomass such as straw using a crusher or cutter to obtain small pieces of 3-10cm. Mix the processed straw evenly with livestock manure such as cow dung to achieve a carbon-to-nitrogen ratio of 25-50. Place a 20-50cm thick layer of the processed organic material into the fermentation chamber using a material cart.

[0055] Step 2: Evenly sprinkle bran, inoculant, auxiliary materials, and spray water on top of the material. The bran should comprise 0-5% of the material's mass, the inoculant 0-0.2%, and a small amount of quicklime and superphosphate (0-1.5%) should be added. Water should be added to maintain the material's moisture content at 60-65%. Commercially available straw fermentation inoculants, such as EM (Effective Microorganisms), can be used.

[0056] Step 3: Continue adding materials and repeat the above process. Close the multi-layer doors of the fermentation chamber layer by layer according to the height of the material pile until the required fermentation scale is reached. Close the outer insulation door to seal the chamber and start fermentation to generate heat.

[0057] (2) The utilization of fermentation heat includes the following steps:

[0058] Step 4: During the high-temperature fermentation period, the hot, humid steam generated in the fermentation chamber is extracted using a piped air extractor. This steam is first passed through a steam-water heat exchanger to exchange heat with cold water, obtaining warm water for heating. Then, it is passed through an air heat exchanger to exchange heat with fresh air, obtaining hot air for oxygen supply. Considering the certain heat demand inside the fermenter and the relatively low oxygen demand, coupled with the limited availability of hot steam, the steam extraction and oxygen supply process is conducted intermittently.

[0059] During steam extraction and ventilation, the volume of the fermentation chamber (≥30m³) should be adjusted accordingly. 3 Based on heat demand, the air extraction flow rate of the pipeline exhaust fan is adjusted to 60–300 m³ / h. 3 / h, the ventilation flow rate of the induced draft fan is adjusted to 30~180m³ / h. 3 When the temperature inside the warehouse drops to 50-60℃, stop high-flow steam extraction and ventilation, and adjust the steam extraction and ventilation flow rates to 0-50m³ / h. 3 / h, heat gradually accumulates in the fermentation chamber, and the temperature slowly rises.

[0060] Step 5: The cold water is pre-softened and stored in a water tank. While steam is being extracted, the cold water is passed through a heat exchanger to obtain usable warm water, which is then sent to the heating area for heat utilization. The water flow rate is set to 0.2–1.5 m³ / h. 3 The water circulates between the heat exchanger and the heating area at a rate of / h, continuously extracting and utilizing heat. When the high-flow steam extraction process stops, the water temperature gradually decreases. When the temperature inside the fermentation chamber rises back to 60-70℃, the circulating water temperature is relatively low, at which point high-flow steam extraction, ventilation, and heat recovery are resumed, and this cycle repeats continuously.

[0061] The principle and operation process of the clean and low-carbon winter heating system for cold regions that uses fermentation heat from agricultural and livestock waste as energy, as described in this invention, are as follows:

[0062] The fermentation pile 19 within the fermentation chamber 28 generates a large amount of heat energy through aerobic fermentation. This heat energy is dissipated through heat conduction, heat convection, and heat radiation. This invention minimizes heat conduction and heat radiation losses by designing the system with insulation; the insulation level depends on the ambient temperature. Most of the heat convection is stored as latent heat in the generated water vapor, with a small portion existing as sensible heat in the hot air and water. This invention primarily utilizes the humid, hot air generated during the fermentation process as a heat source for heat extraction.

[0063] A porous air intake pipe 3 is installed above the pile inside the fermentation chamber 28. Under the action of the pipe exhaust fan 5, the hot and humid air generated by the pile is introduced into the steam-water heat exchanger 6 and cold water through the steam inlet pipe 4 for heat exchange. The condensate generated during the heat exchange flows out of the steam-water heat exchanger 6 under the action of airflow and gravity, and is separated and collected through the drain valve 15. The drain valve 15 can be a free float or an inverted bucket type.

[0064] Hot steam enters the air heat exchanger 10 after passing through the steam-water heat exchanger 6 to heat the fresh air, thereby reducing heat loss inside the fermentation chamber 28 and accelerating the generation of water vapor. Fresh air is introduced into the air heat exchanger by the induced draft fan 26, and then enters the fermentation chamber 28 through the fresh air outlet pipe 11 and the vent pipe 20 below the fermentation chamber 28 for oxygen supply; similarly, condensate is collected during heat exchange. The collected condensate is circulated into the fermentation pile 19 by the spray device 22 under the action of the water pump 27 to replenish water. If the water replenishment is insufficient, it can be supplemented by connecting to an external water source through the external water supply pipe 12.

[0065] The hot steam after use is harmless. After being treated by the filter device 24 to remove odors, it can be discharged or used as gas fertilizer.

[0066] The system uses tap water as the medium for heat storage. After softening, the cold water is stored in the water storage tank 13. Under the action of the water pump 27, it flows into the steam-water heat exchanger 6 for heat exchange. The temperature of the warm water obtained after heat exchange reaches 38-50℃, which can be used directly as domestic water or sent to the heating area 30 for heating. After heating, it is circulated back to the water storage tank 13.

[0067] The inner diameter of the ventilation pipe 20 is 50 - 200 mm, which is distributed at the bottom of the fermentation tank 28 and is connected to the air heat exchanger 10 through the fresh air outlet pipe 11. Holes are opened at the lower sides on both sides of the ventilation pipe 20 to prevent blockage. The holes are opened alternately on the left and right, with a hole diameter of 3 - 10 mm and a spacing of 50 - 150 mm between two holes. The center-to-center spacing of the ventilation pipes 20 is 0.3 - 0.5 m. Cement is filled between the ventilation pipes 20 for bearing, and the height of the cement is higher than the height of the ventilation pipes.

[0068] The multi-layer door 31 of the fermentation tank is used for feeding and discharging. It adopts a multi-layer design, divided into 2 - 5 layers up and down, and the materials are added layer by layer to prevent the materials from collapsing. The outside of the door is made of heat-insulating materials for sealing and heat preservation. An exhaust device is arranged on the side of the fermentation tank 28 to balance the internal air pressure of the fermentation tank and can also be used to discharge excessive accumulated gases such as CO2 inside. The heat extraction room door 32 is located on the side of the heat extraction room 29, and the outer layer is made of heat-insulating materials for sealing and heat preservation.

[0069] The porous air suction pipe 3 is used to suck in the hot and humid air generated by the fermentation pile 19. The inner diameter of the porous air suction pipe 3 is 50 - 200 mm, in a "曰" shape, with holes opened on the upper, lower, left, and right four sides, arranged staggeredly, with a hole diameter of 10 - 30 mm and a spacing of 50 - 150 mm between two holes. A Y-shaped filter can be set at the end of the pipe to remove solid particles in the gas. The pipe air extractor 5 is arranged on the steam inlet pipe 4 to suck in the hot and humid air generated by the fermentation pile 19. The steam-water heat exchanger 6 is used for heat exchange between the hot and humid air and cold water, and adopts a plate type or fin type wall heat exchanger. A support platform 7 is provided below the steam-water heat exchanger 6.

[0070] The water storage tank 13 is in a cuboid shape, and the side with a larger side area is against the wall and insulated by using the middle wall between the fermentation tank 28 and the heat extraction room 29. The air heat exchanger 10 is a wall type steam-air heat exchanger for heat exchange between hot steam and fresh air.

[0071] The heating area 30 is a civilian house or other heat-using units that need heating, with a built-in water softener, and provides water source for the system through the heating water return pipe 17 and the external makeup water pipe 12. The fermentation tank 28, the heat extraction room 29 and the internal equipment have strict heat preservation designs. When the ambient temperature is not lower than -25 °C, the surrounding, bottom and top of the house structure are all insulated with heat-insulating materials such as rubber and plastic boards, polystyrene boards, etc., and the total heat transfer coefficient is controlled at 0.25 - 0.35 w / (m 2 ·K). There are certain heat preservation requirements for the steam-water heat exchanger 6. When the ambient temperature of the room where it is located is 0 - 20 °C, the thermal resistance of the outer shell of the steam-water heat exchanger 6 should not be less than 2.0 (m 2 ·K) / W. Heat-insulating materials such as aerogel felt, polyurethane, etc. can be used. After the water storage tank 13 and the liquid collection tank 8 are insulated, the thermal resistance of the outer shell is not less than 1.0 (m 2 ·K) / W.

[0072] Example 1:

[0073] This invention discloses a clean and low-carbon winter heating system and method for cold regions, utilizing the heat from the fermentation of agricultural and livestock waste as an energy source. The system was applied to winter heating of residential buildings in Northeast China, with outdoor ambient temperatures ranging from -22°C to 0°C. The heated area of ​​the residential building was approximately 90 m². 2 , using 60m 3 The fermentation system requires materials to be piled up to a height of no less than two meters. Since residential buildings typically have built-in heating systems, connecting this system to these systems allows the hot water obtained to be directly supplied to indoor radiators for heating.

[0074] The fermentation process primarily uses corn stalks and cow manure as raw materials. The stalks are cut or crushed to approximately 5cm in size, and appropriate amounts of poultry and livestock manure are added to maintain a carbon-to-nitrogen ratio of 25–40, with an actual measured ratio of around 28. A suitable amount of water is added to maintain a moisture content of 60–65%, with an average of 64.3% measured at multiple locations. Commercially available EM (Effective Microorganisms) and other fermentation inoculants are used. The stalks, poultry and livestock manure, inoculants, and water are added in layers within the fermentation chamber. The layering method is as follows: first, add a 40cm layer of stalks, then add poultry and livestock manure, inoculants, and water in a specific ratio, repeating this process until the entire fermentation chamber is filled.

[0075] The heating system house structure is constructed in three layers. The innermost layer is built with sturdy, supportive materials such as cement; the middle layer is insulated with building insulation materials such as foamed cement and polystyrene board; and finally, a layer of sheet metal is wrapped around the outside for weather protection. To make the structure more stable, the bottom of the house is hardened.

[0076] In the heating room 29, a 15m² heating system is used. 2 Plate heat exchangers with a heat exchange area of ​​24m² are used as steam-water heat exchangers. 2 The shell-and-tube heat exchanger with a heat exchange area serves as the air heat exchanger 10, and also includes 0.51m². 3 The water storage tanks are 13 and 0.13m. 3 Liquid collection tank 8. In the heat extraction room 29, the hot and humid steam generated in the fermentation chamber 28 is introduced into the plate heat exchanger by the pipe exhaust fan 5 and exchanged with cold water. The cold water is used as the heat storage medium. After one heat exchange, the average outlet temperature is measured to reach 42.5℃.

[0077] The heated water is then transported indoors through underground pipes (buried below the frost line). The pipes are made of PPR polyurethane foam with a thickness of at least 30mm. The pumps are housed indoors, and each pump is covered with a sound-insulating cover to prevent noise pollution.

[0078] An indoor water softener is installed to pre-soften the circulating water once, and it is set to soften the water again every 15 days.

[0079] Finally, 60m 3 Fermentation scale for Northeast China 90m 2 For winter heating of a typical residential building, after three rounds of refueling, the system can provide heating for up to five months in outdoor temperatures ranging from -22°C to 0°C, ensuring an indoor temperature that is consistently no lower than 15°C, with an average temperature of 17.7°C. When the outdoor temperature is higher, between -10°C and 0°C, the average indoor temperature reaches 20.3°C. During the heating season, the system's thermal efficiency averages 62.5%, and the average heating power of the building is no less than 9.2 kW.

[0080] Example 2:

[0081] Similarly, as in Example 1, the heating system was used to conduct heating tests in northern regions. The fermentation heating system was connected to heating equipment such as radiators, and the hot water obtained by the system was delivered to indoor radiators for heating.

[0082] Using corn stalks, pig manure, and chicken manure as raw materials, the materials are pre-treated to control the carbon-to-nitrogen ratio within the range of 25–40 (actually measured at 32.5), and the moisture content is maintained at 60–70% (actually measured average at 66.8%). The fermentation scale is 50m³. 3 For a 95m area in North China 2 A certain building is being heated in winter.

[0083] Inside the heat extraction room, a 12m... 2 Plate heat exchangers with a heat exchange area of ​​18m² are used as steam-water heat exchangers. 2 The shell-and-tube heat exchanger with a heat exchange area serves as an air heat exchanger, and also includes 0.51m... 3 The water storage tank and 0.13m 3 The liquid collector. In the heat exchange room, the hot and humid steam generated in the fermentation chamber is circulated into the plate heat exchanger and exchanged with cold water using a piped air pump. The cold water serves as the heat storage medium. After one heat exchange, the average outlet temperature was measured to reach 43.3℃.

[0084] During the heating season, after two rounds of refueling, the system can provide heating for the residence for up to four months in outdoor temperatures ranging from -15°C to 8°C, ensuring an indoor temperature no lower than 18°C, with an average indoor temperature of 20.8°C. During the heating season, the system's average thermal efficiency reaches 65.7%, and the average heating power of the house is no less than 8.5 kW.

[0085] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A clean and low-carbon winter heating system for cold regions that uses the heat from the fermentation of agricultural and livestock waste as energy, characterized in that: It includes a fermentation chamber (28) and a heat extraction room (29), wherein a heat transfer wall separates the fermentation chamber (28) and the heat extraction room (29). The fermentation chamber (28) includes a chamber body, an exhaust device (18), a ventilation pipe (20), a porous suction pipe (3), and a spray device (22). The chamber body contains a fermentation pile (19). An exhaust device (18) is installed on the side wall of the chamber body above the fermentation pile (19). A ventilation pipe (20) is provided at the bottom. A porous suction pipe (3) and a spray device (22) are provided at the top. The heat exchange chamber (29) includes a steam-water heat exchanger (6), a water storage tank (13), an air heat exchanger (10), and a liquid collection tank (8). The liquid collection tank (8) is connected to the steam-water heat exchanger (6) and the air heat exchanger (10) to collect the condensate generated during the heat exchange process. The condensate is pumped by a water pump (27) into a spray device (22) and then into the fermentation chamber (28) to replenish the moisture in the fermentation pile (19). One end of the air heat exchanger (10) is connected to the outside environment. A blower (26) is installed between the gas and water, with one end connected to the ventilation pipe (20) inside the fermentation chamber (28). One end of the steam-water heat exchanger (6) is connected to the porous suction pipe (3), with a pipe exhaust fan (5) installed between them. The other end is connected to the air heat exchanger (10). One end of the water storage tank (13) is connected to the steam-water heat exchanger (6), and the other end is connected to the heating area (30). The side with the larger side area is against the wall and uses the heat conducted by the fermentation chamber (28) for insulation.

2. The clean and low-carbon heating system for cold regions in winter, which uses the fermentation heat of agricultural and livestock waste as energy, as described in claim 1, is characterized in that: The fermentation chamber (28) and the heating room (29) are surrounded by an insulation layer (16), and the overall heat transfer coefficient is controlled at 0.25 to 0.35 W / (m²). 2 ·K).

3. The clean and low-carbon heating system for cold regions in winter, which uses the fermentation heat of agricultural and livestock waste as energy, as described in claim 1, is characterized in that: The hot steam inlet temperature of the steam-water heat exchanger (6) is 60℃~70℃. After one heat exchange, the hot gas outlet temperature drops to below 45℃. After heat exchange by the air heat exchanger (10), the hot gas outlet temperature drops to below 30℃.

4. The clean and low-carbon heating system for cold regions in winter, which uses the fermentation heat of agricultural and livestock waste as energy, as described in claim 3, is characterized in that: The steam-water heat exchanger (6) has a cold water inlet temperature of 5-10℃, a circulating water inlet temperature of 20-30℃, and an outlet water temperature of 40-50℃.

5. The clean and low-carbon heating system for cold regions in winter, which uses the fermentation heat of agricultural and livestock waste as energy, as described in claim 1, is characterized in that: The air heat exchanger (10) has a cold air inlet temperature of -20 to 10°C. The lower the temperature, the more obvious the heating effect. After heat exchange, the cold air outlet temperature can reach 20°C to 30°C.

6. The clean and low-carbon heating system for cold regions in winter, which uses the fermentation heat of agricultural and livestock waste as energy, as described in claim 1, is characterized in that: Under the action of the pipeline pump (5), the humid and hot air generated by the pile body is introduced into the steam-water heat exchanger (6) and cold water through the steam inlet pipe (4) for heat exchange. The condensate generated during the heat exchange flows out of the steam-water heat exchanger (6) under the action of airflow and gravity, and is separated and collected through the drain valve (15).

7. The clean and low-carbon heating system for cold regions in winter, which uses the fermentation heat of agricultural and livestock waste as energy, as described in claim 1, is characterized in that: The system uses tap water as a medium for heat storage. After softening, the cold water is stored in the water storage tank (13). Under the action of the water pump (27), it flows into the steam-water heat exchanger (6) for heat exchange. The temperature of the warm water obtained after heat exchange reaches 38-50℃, which can be used directly as domestic water or sent to the heating area (30) for heating. After heating, it is circulated back to the water storage tank (13).

8. A heating method using the cold-region winter clean and low-carbon heating device based on the fermentation heat of agricultural and livestock waste as an energy source, as described in any one of claims 1-7, characterized in that: This includes the processes of aerobic fermentation heat generation and fermentation heat utilization; (1) Aerobic fermentation heat production includes the following steps: Step 1: The cellulose biomass is crushed by a cutting and crushing device. The treated straw and livestock manure are mixed evenly so that the carbon-nitrogen ratio of the material is 25-50. The treated organic material with a thickness of 20-50cm is spread in the fermentation chamber (28) by a material cart. Step 2: Evenly sprinkle bran, inoculant, auxiliary materials and spray water on top of the material. The bran accounts for 0-5% of the material mass, the fermentation inoculant accounts for 0-0.2%, and a small amount of quicklime and superphosphate auxiliary materials are added, accounting for 0-1.5%. Water is added to control the moisture content of the material at 60-65%. Step 3: Continue adding materials and repeat the above addition process. Close the fermentation chamber door layer by layer according to the height of the material pile until the required fermentation scale is reached. Close the outer insulation door to seal the chamber and start fermentation to generate heat. (2) The utilization of fermentation heat includes the following steps: Step 4: During the high-temperature fermentation period, the hot and humid steam generated in the fermentation chamber (28) is extracted using a pipe exhaust fan (5). It is first introduced into a steam-water heat exchanger (6) to exchange heat with cold water to obtain warm water for heating. Then it is introduced into an air heat exchanger (10) to exchange heat with fresh air to obtain hot air for oxygen supply. The steam extraction and ventilation oxygen supply process is carried out in an intermittent manner. Step 5: The cold water is softened in advance and stored in the water storage tank (13). While the steam is being extracted, the cold water is passed into the steam-water heat exchanger (6) to exchange heat and obtain warm water. The warm water is sent to the heating area (30) for heat utilization. The water circulates between the steam-water heat exchanger (6) and the heating area (30) for uninterrupted heat extraction and heat utilization. When the large-flow steam extraction process stops, the water temperature gradually decreases. When the temperature in the fermentation chamber (28) rises to 60-70℃, the circulating water temperature is low. Then, the large-flow steam extraction, ventilation and heat recovery are carried out again, and the cycle is repeated.

9. The method for clean and low-carbon winter heating in cold regions using fermentation heat from agricultural and livestock waste as energy, as described in claim 8, is characterized in that: In step 1, the cellulose biomass is crushed by a pulverizer or cutter to obtain small segments of 3-10 cm.

10. The method for clean and low-carbon winter heating in cold regions using fermentation heat from agricultural and livestock waste as energy, as described in claim 8, is characterized in that: In step 4, during the steam extraction and ventilation process, the steam extraction flow rate of the pipeline exhaust fan (5) is adjusted to 60-300 m³ / h according to the volume of the fermentation chamber (28) and the heat demand. 3 / h, the ventilation flow rate of the induced draft fan (26) is adjusted to 30-180m³ / h. 3 When the temperature inside the warehouse drops to 50-60℃, stop high-flow steam extraction and ventilation, and adjust the steam extraction and ventilation flow rates to 0-50m³ / h. 3 / h, heat gradually accumulates in the fermentation chamber (28), and the temperature slowly rises.

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