biogas combustion heating fire wall

Abstract

This utility model discloses a biogas combustion heating fire wall, comprising a hollow fire wall formed by vertically stacked brick walls. The fire wall contains a backfill area filled with heat-conducting material. Within the backfill area are flue gas flow channels and a combustion chamber extending along the wall's extension direction. Each flue gas flow channel contains a biomass flue gas flow pipe, which conducts heat with the backfill area and is connected to a biomass combustion furnace. The combustion chamber contains a biogas delivery pipe and a biogas ignition device. The inlet of the biogas delivery pipe is connected to a biogas generator. Along the biogas delivery direction, a biogas concentration monitoring system and a flow valve are sequentially installed on the biogas delivery pipe. The biogas generator supplies biogas to the combustion chamber via the biogas delivery pipe, which is then ignited by the biogas ignition device for combustion and heating. A control system, including at least a controller, is located on one side of the fire wall to ensure complete combustion, safety, and combined heating, making it a green and low-carbon solution.

Description

Technical Field

[0001] This utility model relates to the field of smart green agriculture technology, and in particular to biogas combustion heating fire wall. Background Technology

[0002] In recent years, China's facility agriculture has developed rapidly, with continuous optimization of the agricultural industrial structure and a significant expansion in the scale of greenhouses. Against this backdrop, maintaining suitable temperatures for crop growth within greenhouses is crucial. To achieve this, producers initially used hot air blowers for greenhouse heating, but later, to reduce costs, they replaced these blowers with traditional firewalls. However, as... Figure 3 As shown, traditional fire walls only have flue gas circulation channels inside, which are connected to the stove or an external combustion chamber. High-temperature flue gas or flames are sent to the flue gas circulation channels by burning straw or coal, resulting in high pollution and high carbon emissions in the heating method. Traditional firewalls rely on a single heat source, typically a single combustion source, resulting in poor heating flexibility and a lack of intelligence in their use. They are somewhat outdated when facing smart greenhouses and smart agriculture, still mainly relying on human operation and control, leading to low efficiency and a lack of automatic switching and heating capabilities.

[0003] Therefore, in order to solve the above-mentioned problems and optimize the traditional firewall, this invention develops a new type of firewall based on biogas combustion heating to assist agricultural production by utilizing readily available biogas resources in rural areas. Utility Model Content

[0004] This utility model provides a biogas combustion heating fire wall, which aims to solve the problems of high pollution, single heat source and poor self-control of the existing traditional fire wall heating methods mentioned above.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: The biogas combustion heating fire wall includes a hollow fire wall formed by vertically stacking brick walls. The fire wall contains a backfill area filled with heat-conducting material. The backfill area is provided with flue gas circulation channels and combustion chambers that extend through the fire wall along the wall's extension direction. Each of the flue gas circulation channels is equipped with a biomass flue gas circulation pipe, and the biomass flue gas circulation pipe forms a heat conduction with the backfill area. The feed inlet of the biomass flue gas circulation pipe is connected to the output port of the biomass combustion furnace. The combustion chamber is equipped with a biogas delivery pipeline and a biogas ignition device. The inlet of the biogas delivery pipeline is connected to the biogas generator. A biogas concentration monitoring system and a flow valve are sequentially installed on the biogas delivery pipeline along the biogas delivery direction. The biogas generator supplies biogas to the combustion chamber through the biogas delivery pipeline, which is then ignited by the biogas ignition device for combustion and heat supply. One side of the firewall is equipped with a control system including at least a controller. The biogas concentration monitoring system, flow valve, biogas ignition device and biomass combustion furnace are all electrically connected to the control system.

[0006] Preferably, the flow valve, biogas ignition device, and biomass combustion furnace are linked with the biogas concentration monitoring system through the control system, and the biogas combustion furnace and the biogas combustion line including the flow valve and biogas ignition device are configured as "one for standby and one for use" through the biogas concentration monitoring system and the control system.

[0007] Preferably, the firewall is located in the corridor inside the greenhouse and does not occupy the planting area.

[0008] Preferably, the thermally conductive material is a mixture of clay and sand, with the proportion of clay being greater than the proportion of sand.

[0009] Preferably, an axial flow fan is provided on the side of the fire wall away from the biogas inlet, and the outlet of the biomass flue gas circulation pipe is connected to the axial flow fan and forms an air outlet coordination with the outside of the greenhouse.

[0010] More preferably, the combustion chamber is provided with an exhaust pipe at the end away from the biogas inlet, and the combustion chamber is connected to an axial flow fan through the exhaust pipe to form an exhaust connection with the outside of the greenhouse.

[0011] Furthermore, several oxygen channels are provided on both sides of the combustion chamber, and the combustion chamber is connected to the greenhouse outside the fire wall through the oxygen channels. The combustion chamber and the interior of the oxygen channels are connected by an axial flow fan to form a negative pressure.

[0012] Furthermore, the axial flow fan outlet is equipped with a biogas concentration alarm. The biogas concentration alarm is used to sense the biogas concentration in the gas at the outlet of the exhaust pipe and to issue an alarm when the concentration exceeds the set value. The biogas concentration alarm is linked with the flow valve and the biogas ignition device through the control system.

[0013] Preferably, the biogas delivery pipeline is fixedly installed at the bottom of the combustion chamber by a fixed bracket. The top of the biogas delivery pipeline is provided with a biogas delivery port that communicates with the combustion chamber. A branch valve is provided on the biogas delivery port. The biogas ignition device is buried in the backfill area near the biogas delivery port. The ignition port of the biogas ignition device extends into the combustion chamber and is close to the end of the biogas delivery port to ignite the biogas.

[0014] More preferably, a flame detector is provided at the top of the combustion chamber. The flame detector is used to sense whether there is a flame in the combustion chamber. The flame detector is linked with the flow valve, branch valve and biogas ignition device through the control system.

[0015] The beneficial effects of this utility model are: (1) The biogas combustion heating fire wall proposed in this utility model uses clean energy instead of coal as the combustion source of the traditional fire wall. The biogas generated after the treatment of rural sewage is transported to the fire wall in the greenhouse. The heat generated by the combustion of biogas in the fire wall largely solves the heating problem of the greenhouse, achieving low cost, high efficiency, reducing environmental pollution, and improving the recycling rate of clean energy. (2) At the same time, the traditional fire wall heating design is retained, and the biomass combustion furnace and biogas digester are used together. When the biogas concentration is insufficient, the biomass combustion furnace can be switched to ensure heating efficiency. At the same time, the pollution caused by simply using biomass combustion is reduced. When the biogas concentration is sufficient, biogas combustion is used for heating to maintain low carbon and environmental protection as much as possible. A balance is achieved between continuous heating and green environmental protection. The switching process is automatically switched by monitoring the biogas concentration, which improves self-control and flexibility. (3) The biogas concentration alarm can monitor whether the biogas is completely burned, while the flame detector can monitor whether the ignition is normal, thus improving the overall self-control of the device. When an abnormality occurs, the fire wall heating will be shut off and personnel will be notified to carry out maintenance. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the installation from one perspective of the present invention; Figure 2 This is an installation diagram from another perspective of the present invention; Figure 3 This is a cross-sectional schematic diagram of a traditional firewall; Figure 4 This is a cross-sectional schematic diagram of the firewall of this utility model; Figure 5 This is a cross-sectional schematic diagram of the combustion chamber of this utility model; Figure 6 This is a plan view of the firewall of this utility model; In the diagram: 1. Flue gas flow channel; 2. Backfill area; 3. Brick wall; 4. Oxygen passage; 5. Combustion chamber; 6. Biogas delivery port; 7. Branch valve; 8. Biogas delivery pipeline; 9. Fixed support; 10. Biogas ignition device; 11. Ignition port; 12. Flame detector; 13. Biogas generator; 14. Biogas concentration monitoring system; 15. Flow valve; 16. Biogas concentration alarm; 17. Biomass flue gas flow pipeline; 18. Fire wall; 19. Exhaust duct; 20. Axial flow fan; 21. Greenhouse; 22. Biomass combustion furnace; 23. Control system. Detailed Implementation

[0017] The embodiments will be further described below with reference to the accompanying drawings.

[0018] like Figure 1 , Figure 2 and Figure 6 As shown, in a preferred embodiment 1, the biogas combustion heating fire wall includes a hollow fire wall 18 formed by stacking brick walls 3 in the vertical direction. The fire wall 18 is filled with a soil filling area 2 filled with heat-conducting material. The soil filling area 2 is provided with a flue gas flow channel 1 and a combustion chamber 5 that extend through the fire wall 18 along the wall extension direction. Each flue gas flow channel 1 is equipped with a biomass flue gas flow pipe 17, and the biomass flue gas flow pipe 17 forms a heat conduction with the backfill area 2. The feed inlet of the biomass flue gas flow pipe 17 is connected to the output port of the biomass combustion furnace 22. The combustion chamber 5 is equipped with a biogas delivery pipeline 8 and a biogas ignition device 10. The inlet of the biogas delivery pipeline 8 is connected to the biogas generator 13. The biogas delivery pipeline 8 is equipped with a biogas concentration monitoring system 14 and a flow valve 15 along the biogas delivery direction. The biogas generator 13 supplies biogas to the combustion chamber 5 through the biogas delivery pipeline 8, which is then ignited by the biogas ignition device 10 for combustion and heat supply. One side of the firewall 18 is equipped with a control system 23, which includes at least a controller. The biogas concentration monitoring system 14, flow valve 15, biogas ignition device 10 and biomass combustion furnace 22 are all electrically connected to the control system 23.

[0019] Both the brick wall 3 and the earth filling area 2 are common structures of the fire wall 18. This patent sets up a flue gas circulation channel 1 and a combustion chamber 5 for two heating methods. The two methods are used in combination and can be switched automatically. The flue gas flow channel 1 is used for the installation of the biomass flue gas flow pipe 17 of the biomass combustion furnace 22, and is used for biomass combustion heating. The biogas delivery pipeline 8 is used to deliver biogas generator 13 to combustion chamber 5 at a constant flow rate through flow valve 15. Flow valve 15 is a solenoid valve. During the process, biogas concentration monitoring system 14 monitors the biogas concentration from biogas generator 13. Biogas concentration monitoring system 14 is a biogas concentration sensor. After the biogas in combustion chamber 5 is mixed with air, it is ignited by biogas ignition device 10 for combustion and heat supply. The combined use of the two methods is controlled by the programmable PLC controller within the control system 23.

[0020] In a preferred embodiment 2, the flow valve 15, the biogas ignition device 10, and the biomass combustion furnace 22 are linked with the biogas concentration monitoring system 14 through the control system 23, and the biogas combustion furnace 22 and the biogas combustion line including the flow valve 15 and the biogas ignition device 10 are connected to form a "one-for-one" system through the biogas concentration monitoring system 14 and the control system 23.

[0021] Based on Example 1, the two methods can be used in combination as "one for backup and one for use". The biogas concentration monitoring system 14 monitors the biogas concentration from the biogas generator 13 in real time. When the biogas concentration is lower than the set value, the biogas concentration monitoring system 14 sends a signal to the controller of the control system 23. The controller closes the flow valve 15 and the biogas ignition device 10 to stop the biogas delivery and ignition, and then starts the biomass combustion furnace 22 to use biomass combustion to provide heat in relay and ensure continuous heating. When the biogas concentration is higher than the set value, the biogas concentration monitoring system 14 sends a signal to the controller of the control system 23. The controller shuts down the biomass combustion furnace 22 and then starts the flow valve 15 and the biogas ignition device 10 to deliver biogas and ignite it. The biogas combustion is used to provide heat in relay, ensuring continuous heating, while being green and environmentally friendly and reducing pollution.

[0022] The biogas concentration monitoring system 14 can also use an online gas detector and optionally be equipped with a wireless module to transmit real-time monitoring data to the control system.

[0023] like Figure 1 and Figure 2 As shown, in a preferred embodiment 3, the firewall 18 is located on the corridor inside the greenhouse 21 and does not occupy the planting area.

[0024] In a preferred embodiment 4, the thermally conductive material is a mixture of clay and sand, with the proportion of clay being greater than the proportion of sand.

[0025] Ensure the thermal conductivity and heat storage capacity of the backfill area 2. When heating begins, ensure a certain thermal conductivity so that the fire wall 18 can dissipate heat outwards but not too quickly or too violently, so as to avoid the temperature inside the greenhouse 21 rising too fast or too high. When heating is stopped, the fire wall 18 can continue to release heat to the greenhouse 21 due to the heat storage capacity of the soil filling area 2 inside the fire wall 18, until the wall temperature cools down to the same temperature as the ambient temperature of the greenhouse 21.

[0026] like Figure 1 , Figure 2 , Figure 4 and Figure 6 As shown in the preferred embodiment 5, an axial flow fan 20 is provided on the side of the fire wall 18 away from the biogas inlet. The outlet of the biomass flue gas circulation pipe 17 is connected to the axial flow fan 20 and forms an exhaust system with the outside of the greenhouse 21. This ensures timely discharge of combustion products and maintains negative pressure.

[0027] The combustion chamber 5 is equipped with an exhaust pipe 19 at its end furthest from the biogas inlet. The combustion chamber 5 is connected to the axial flow fan 20 through the exhaust pipe 19 and forms an exhaust connection with the outside of the greenhouse 21. Even when combustion products are discharged, negative pressure is maintained.

[0028] The combustion chamber 5 is provided with several oxygen channels 4 on both sides. The combustion chamber 5 is connected to the greenhouse 21 outside the fire wall 18 through the oxygen channels 4, and the combustion chamber 5 and the interior of the oxygen channels 4 are connected by an axial flow fan 20 to create a negative pressure. Under negative pressure, air enters the combustion chamber 5 through the oxygen channels 4 and mixes with biogas, which facilitates complete combustion after being ignited by the biogas ignition device 10. At the same time, the negative pressure guides the direction of the flame to ensure that the flame does not leak out of the fire wall 18.

[0029] The axial flow fan 20 is used to draw in the biomass flue gas flow duct 17 and the combustion chamber 5 to create a negative pressure, so as to draw out the flue gas and products after combustion in time and discharge them to the outside of the greenhouse 21 to avoid affecting the environment inside the greenhouse 21. At the same time, the negative pressure is created in the biomass flue gas flow duct 17 and the combustion chamber 5 so that the flue gas and flame are directed towards the axial flow fan 20, and to prevent the flame in the combustion chamber 5 from leaking out from the oxygen channel 4.

[0030] Preferably, the length of the flame after combustion is controlled by controlling the power of the axial flow fan 20 and the concentration of biogas, so as to ensure that the length of the flame does not directly contact the axial flow fan 20. At the same time, fireproof coating is provided on the axial flow fan 20 and the tail end where it may come into direct contact with the flame.

[0031] The axial flow fan 20 can be a wall-mounted explosion-proof fan.

[0032] like Figure 1 , Figure 2 and Figure 6 As shown in the preferred embodiment 6, the outlet of the axial flow fan 20 is equipped with a biogas concentration alarm 16. The biogas concentration alarm 16 is used to sense the biogas concentration in the gas at the outlet of the exhaust pipe 19 and issue an alarm when it exceeds the set value. The biogas concentration alarm 16 is linked with the flow valve 15 and the biogas ignition device 10 through the control system 23.

[0033] The biogas concentration alarm 16 is mainly used to detect whether biogas combustion is complete. When the biogas concentration in the combustion product exceeds the standard, an alarm is issued, indicating that the biogas has not been completely burned and there is a certain risk. At this time, the biogas concentration alarm 16 sends a signal to the controller of the control system 23. The controller closes the flow valve 15 and the biogas ignition device 10. After hearing the alarm, the personnel need to reset the flow valve 15 and the axial flow fan 20 and make adjustments to ensure that the combustion is sufficient and complete, and that the biogas concentration in the combustion product is lower than the set value.

[0034] like Figure 4 and Figure 5As shown in the preferred embodiment 7, the biogas delivery pipeline 8 is fixedly installed at the bottom of the combustion chamber 5 by a fixed bracket 9. The top of the biogas delivery pipeline 8 is provided with a biogas delivery port 6 that communicates with the combustion chamber 5. A branch valve 7 is provided on the biogas delivery port 6. The biogas ignition device 10 is buried in the backfill area 2 near the biogas delivery port 6. The ignition port 11 of the biogas ignition device 10 extends into the combustion chamber 5 and is close to the end of the biogas delivery port 6 to ignite the biogas.

[0035] The biogas ignition device 10 uses an electric arc igniter. Biogas is transported to the combustion chamber 5 through the biogas delivery pipeline 8 and enters the combustion chamber 5 through the biogas delivery port 6, where it mixes with the oxygen entering through the oxygen channel 4. After being ignited by the ignition port 11 of the biogas ignition device 10, it burns. The branch valve 7 is also a high-temperature resistant electromagnetic valve, used for secondary control of the amount of biogas released. Initially, the branch valve 7 is closed, and the timer in the control system 23 is used to set the time. The time is roughly calculated based on the flow rate and the total length of the biogas delivery pipeline 8 with the branch valve 7. The main purpose of the timer is to make the biogas delivery pipeline 8 as full as possible. The end of the biogas delivery pipeline 8 is sealed, and the biogas is released only through the branch valve 7 and the biogas delivery port 6. When the timer ends, the controller opens the branch valve 7 to release the biogas for ignition.

[0036] like Figure 5 As shown, in a preferred embodiment 8, a flame detector 12 is provided at the top of the combustion chamber 5. The flame detector 12 is used to sense whether there is a flame in the combustion chamber 5. The flame detector 12 is linked with the flow valve 5, the branch valve 7 and the biogas ignition device 10 through the control system 23.

[0037] The flame detector 12 here uses a flame sensor, which is installed at the interface between the combustion chamber 5 and the oxygen channel 4. It is mainly used to detect whether there is a flame and to assist in detecting the size of the flame. Some flame sensors, such as the HY-A1 model, provide an analog voltage output. The voltage value is inversely proportional to the flame intensity: the stronger the flame, the lower the output voltage. When no flame is detected, it indicates that there is a problem with ignition or that it has not been ignited. The flow valve 15 and the biogas ignition device 10 are shut off by the controller of the control system 23 for maintenance and testing. Based on the approximate intensity of the flame, control the release amount of branch valve 7, and cooperate with flow valve 15 and axial flow fan 20 to control the flame within the required range. If the flame is too large, gradually reduce the release amount of branch valve 7 and gradually increase the power of axial flow fan 20 until the flame is within the set range.

[0038] like Figure 1 , Figure 2 and Figure 6As shown in the preferred embodiment 9, there are multiple combustion chambers 5, which are equally spaced along the fire wall 18. Adjacent combustion chambers 5 are connected and fitted together to form a candied hawthorn shape. Each combustion chamber 5 has an oxygen channel 4 on both sides that corresponds to and is connected to the combustion chamber 5. Each combustion chamber 5 is equipped with a corresponding flame detector 12, a biogas inlet 6, and a biogas ignition device 10.

[0039] As a preferred embodiment 10, the flue gas flow channel 1 has a diameter of 70 mm, extends along the wall and penetrates the fire wall 18, and there are four of them, which are symmetrically arranged in pairs about the combustion chamber 5. Multiple combustion chambers 5 are arranged at equal intervals along the extension direction of the traditional fire wall 18. The combustion chambers 5 are located in the middle of the wall, and adjacent combustion chambers 5 are interconnected. The same biogas delivery pipe 8 is embedded in the combustion chambers 5. The fire wall is 1000mm high, the outer brick wall 3 is 100mm thick, and the diameter of the combustion chamber 5 is 200mm. Oxygen channels 4 are opened at symmetrical positions along the lateral direction in each combustion chamber 5. The oxygen channels 4 are 100mm high. The greenhouse 21 is designed to be 10000mm long and 6000mm wide. The fire wall 18 is 8000mm long and 600mm wide. An oxygen channel 4 is set every 1000mm, and the oxygen channel 4 is 300mm wide.

[0040] As a preferred embodiment 11, the method for providing heat using the firewall 18 of this patent includes the following steps: Step 1: The biogas produced by the biogas generator 13 is transported to the firewall 18 through the biogas delivery pipeline 8. The biogas delivery pipeline 8 runs through the firewall 18, and a biogas concentration monitoring system 14 and a flow valve 15 are installed at the inlet of the biogas delivery pipeline 8. The biogas concentration monitoring system 14 monitors the biogas concentration and transmits the monitoring data to the control system 23 in the form of an electrical signal. According to the preset safe flow value, the flow valve 15 is automatically opened and closed to control the biogas input. Step 2: Biogas enters the biogas delivery pipe 8 inside the fire wall 18 through the flow valve 15 and the timing begins. At this time, the branch valves 7 connecting each combustion chamber 5 are closed. After the biogas fills the entire delivery pipe 8, the biogas ignition device 10, branch valves 7, and axial flow fan 20 are started simultaneously. As biogas is discharged from the biogas delivery port 6 into the biogas combustion chamber 5, the biogas ignition device 10 controls the ignition port 11 to ignite the biogas. During the biogas combustion process, the flame detection system 12 continuously monitors the flame and transmits the data to the control system 23. Based on the input data, the size of each branch valve 7 and the air force of the axial flow fan 20 are adjusted to achieve complete combustion of biogas and maximize efficiency. If the flame is too small, the release of the branch valve 7 is gradually increased and the power of the axial flow fan 20 is gradually reduced until the flame is within the required range. Step 3: When the fire wall 18 is running, if the flame detection system 12 detects that any combustion chamber 5 fails to ignite or accidentally goes out, or the biogas concentration alarm 16 sounds an alarm, the control system 23 will immediately cut off the flow valve 5 and the branch valve 7 to troubleshoot the fault. Step 4: Once the biogas concentration monitoring system 14 detects that the biogas concentration is lower than the set value, the control system 23 will automatically stop the biogas input. If the greenhouse 21 still needs to be heated continuously, the traditional method of burning biomass to heat the fire wall will be used.

[0041] The working principle of this utility model: Both the brick wall 3 and the earth filling area 2 are common structures of the fire wall 18. This patent sets up a flue gas circulation channel 1 and a combustion chamber 5 for two heating methods. The two methods are used in combination and can be switched automatically. The flue gas flow channel 1 is used for the installation of the biomass flue gas flow pipe 17 of the biomass combustion furnace 22, and is used for biomass combustion heating. The biogas delivery pipeline 8 is used to deliver biogas generator 13 to combustion chamber 5 at a constant flow rate through flow valve 15. Flow valve 15 is a solenoid valve. During the process, biogas concentration monitoring system 14 monitors the biogas concentration from biogas generator 13. Biogas concentration monitoring system 14 is a biogas concentration sensor. After the biogas in combustion chamber 5 is mixed with air, it is ignited by biogas ignition device 10 for combustion and heat supply. The combined use of the two methods is controlled by the programmable PLC controller within the control system 23.

Claims

1. A biogas combustion heating fire wall characterized by, It includes a hollow fire wall (18) formed by stacking brick walls (3) in the vertical direction. The fire wall (18) is filled with a soil filling area (2) filled with heat-conducting material. The soil filling area (2) is provided with a flue gas flow channel (1) and a combustion chamber (5) that penetrate the fire wall (18) along the extension direction of the wall. Each of the flue gas flow channels (1) is equipped with a biomass flue gas flow pipe (17), and the biomass flue gas flow pipe (17) forms a heat conduction with the backfill area (2). The feed inlet of the biomass flue gas flow pipe (17) is connected to the output port of the biomass combustion furnace (22). The combustion chamber (5) is equipped with a biogas delivery pipe (8) and a biogas ignition device (10). The inlet of the biogas delivery pipe (8) is connected to the biogas generator (13). A biogas concentration monitoring system (14) and a flow valve (15) are installed on the biogas delivery pipe (8) along the biogas delivery direction. The biogas generator (13) supplies biogas to the combustion chamber (5) through the biogas delivery pipe (8). After being ignited by the biogas ignition device (10), the biogas is burned for heat supply. The firewall (18) is provided with a control system (23) including at least a controller on one side. The biogas concentration monitoring system (14), flow valve (15), biogas ignition device (10) and biomass combustion furnace (22) are all electrically connected to the control system (23).

2. The biogas combustion heating firewall of claim 1, wherein, The flow valve (15), biogas ignition device (10) and biomass combustion furnace (22) are linked with the biogas concentration monitoring system (14) through the control system (23), and the biomass combustion furnace (22) and the biogas combustion line including the flow valve (15) and biogas ignition device (10) are linked with the biogas concentration monitoring system (14) and the control system (23) to form a "one-for-one" system.

3. The biogas combustion heating fire wall according to claim 1, characterized in that, The firewall (18) is located on the corridor inside the greenhouse (21) and does not occupy the planting area.

4. The biogas combustion heating fire wall according to claim 1, characterized in that, The thermally conductive material is a mixture of clay and sand, with the proportion of clay being greater than the proportion of sand.

5. The biogas combustion heating fire wall according to claim 1, characterized in that, The fire wall (18) is equipped with an axial flow fan (20) on the side away from the biogas inlet. The outlet of the biomass flue gas circulation pipe (17) is connected to the axial flow fan (20) and forms an air outlet with the outside of the greenhouse (21).

6. The biogas combustion heating fire wall according to claim 5, characterized in that, The combustion chamber (5) is provided with an exhaust pipe (19) at the end away from the biogas inlet. The combustion chamber (5) is connected to the axial flow fan (20) through the exhaust pipe (19) and forms an exhaust gas connection with the outside of the greenhouse (21).

7. The biogas combustion heating fire wall according to claim 6, characterized in that, The combustion chamber (5) is provided with several oxygen channels (4) on both sides. The combustion chamber (5) is connected to the greenhouse (21) outside the fire wall (18) through the oxygen channels (4). The combustion chamber (5) and the oxygen channels (4) are connected by an axial flow fan (20) to form a negative pressure.

8. The biogas combustion heating fire wall according to claim 7, characterized in that, The axial flow fan (20) is equipped with a biogas concentration alarm (16) at the air outlet. The biogas concentration alarm (16) is used to sense the biogas concentration in the gas at the air outlet of the exhaust pipe (19) and issue an alarm when the concentration exceeds the set value. The biogas concentration alarm (16) is linked with the flow valve (15) and the biogas ignition device (10) through the control system (23).

9. The biogas combustion heating fire wall according to claim 1, characterized in that, The biogas delivery pipeline (8) is fixedly installed at the bottom of the combustion chamber (5) by a fixed bracket (9). The top of the biogas delivery pipeline (8) is provided with a biogas delivery port (6) that communicates with the combustion chamber (5). A branch valve (7) is provided on the biogas delivery port (6). The biogas ignition device (10) is buried in the backfill area (2) on the side close to the biogas delivery port (6). The ignition port (11) of the biogas ignition device (10) extends into the combustion chamber (5) and is close to the end of the biogas delivery port (6) to ignite the biogas.

10. The biogas combustion heating fire wall according to claim 9, characterized in that, The combustion chamber (5) is equipped with a flame detector (12) at the top. The flame detector (12) is used to sense whether there is a flame in the combustion chamber (5). The flame detector (12) is linked with the flow valve (15), the branch valve (7) and the biogas ignition device (10) through the control system (23).

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