On-line detection system and method for combustible gas of sludge pyrolysis gasifier

Abstract

The invention relates to a sludge pyrolysis gasifier combustible gas on-line detection system and method.The sludge pyrolysis gasifier combustible gas on-line detection system comprises a combustible gas detection pipeline, a self-priming pump and a combustible gas valve are sequentially arranged on the combustible gas detection pipeline, the combustible gas detection pipeline is communicated with the bottom of a gas filtering device, and a tap water pipeline is arranged in the middle of the gas filtering device; an activated carbon layer and a filter cotton layer are sequentially arranged at the upper position in the gas filter device from bottom to top, an upper-layer pressure sensor is arranged on the upper portion of the filter cotton layer, a lower-layer pressure sensor is arranged on the lower portion of the activated carbon layer, and an exhaust pipeline is arranged at the top end of the gas filter device. And a carbon monoxide detector, a carbon dioxide detector and an oxygen detector are arranged on the exhaust pipeline. According to the invention, impurities such as tar, dust and water are removed through three times of filtration, then detection is carried out by the detection equipment, and the gasification furnace is controlled through the PLC according to detection data.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge pyrolysis gasification, and in particular relates to an online detection system and method for combustible gas in a sludge pyrolysis gasification furnace. Background Art

[0002] Sludge pyrolysis and gasification is a new technology for sludge treatment, such as CN105255518A, a sludge combustible gasification method and CN105238448A, a sludge combustible gasification device. Sludge pyrolysis and gasification technology is a system engineering that uses sludge pyrolysis and gasification as the core technology for sludge disposal, relying on drying, granulation, tail gas disposal, and waste residue utilization. The main purpose is to make large-scale sludge reduction, harmlessness, and resource utilization a reality under the premise of being odorless and pollution-free. Compared with the existing technology, sludge pyrolysis and gasification technology can achieve sludge reduction, harmlessness, stabilization, and resource utilization. The utilization rate of organic matter in sludge by pyrolysis and gasification technology is as high as 70%. Under high temperature and oxygen deficiency, organic matter is pyrolyzed into combustible gases such as carbon monoxide, hydrogen, and alkanes, which can be used more conveniently and cleanly. After pyrolysis and high-temperature treatment, the volume of sludge is greatly reduced. After gasification, the organic matter flows out in the form of gas. The remaining inorganic matter is fluidized at high temperature, with higher density, heavier quality, and greatly increased strength. It is used to make fire-free building materials for repeated use. After sludge gasification, the combustible gas contains combustible components such as carbon monoxide, hydrogen, and methane, as well as impurities such as tar, dust, and moisture. During the gas composition detection process of combustible gas, impurities such as tar, dust, and moisture will block the pipeline, block and corrode the gas sensor probe, causing sensor failure and seriously affecting the gas detection accuracy.

[0003] Therefore, there is an urgent need for a combustible gas filtering and detection equipment, and at the same time, the operating parameters of the gasifier can be adjusted by detection to ensure the safety of the sludge pyrolysis gasification treatment operation. Summary of the invention

[0004] In order to solve the problem that the existing combustible gas detection equipment is affected by impurities such as tar, dust, moisture, etc. during use, resulting in low detection accuracy, the present invention provides an online detection system and method for combustible gas in a sludge pyrolysis gasification furnace. The combustible gas enters a gas filtering device and is filtered three times to remove impurities such as tar, dust, moisture, etc., and then is detected by the detection equipment. The gasifier is controlled by a PLC controller based on the detection data to ensure the detection accuracy, thereby providing a basis for the safe implementation of sludge pyrolysis gasification treatment operations.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present invention proposes an online detection system for combustible gas in a sludge pyrolysis gasification furnace, comprising a gasification furnace, a buffer silo is arranged at the upper part of the gasification furnace, a blower is arranged at the lower part of the gasification furnace, and also comprises a gas filtering device, a combustible gas detection pipeline is arranged between the gas filtering device and the gasification furnace, a self-priming pump and a combustible gas valve are arranged on the combustible gas detection pipeline in sequence, the combustible gas detection pipeline is connected to the bottom of the gas filtering device, a tap water pipeline is arranged in the middle part of the gas filtering device, a tap water inlet valve is arranged on the tap water pipeline, an activated carbon layer and a filter cotton layer are arranged in sequence from bottom to top at the upper position inside the gas filtering device, an upper pressure sensor is arranged on the upper part of the filter cotton layer, a lower pressure sensor is arranged on the lower part of the activated carbon layer, an exhaust pipeline is arranged at the top of the gas filtering device, and a carbon monoxide detector, a carbon dioxide detector and an oxygen detector are arranged on the exhaust pipeline; A magnetic flap level gauge and an upper sewage pipe are arranged in the middle of the gas filter device, a first sewage valve is arranged on the upper sewage pipe, and a lower sewage pipe is arranged at the bottom of the gas filter device, a second sewage valve is arranged on the lower sewage pipe; The self-priming pump, combustible gas valve, tap water inlet valve, carbon monoxide detector, carbon dioxide detector, oxygen detector, upper pressure sensor, lower pressure sensor, first sewage valve, magnetic flap level gauge and second sewage valve are connected to a PLC controller.

[0006] Furthermore, the gas filtering device comprises a furnace body and a furnace cover, the furnace body and the furnace cover are flange-connected, and the activated carbon layer and the filter cotton layer are detachably connected to the inner wall of the furnace body.

[0007] The furnace body and furnace cover are connected by flange, which is convenient for fixing and disassembling. The furnace body and furnace cover are connected in a detachable manner, which is convenient for replacing the activated carbon layer and filter cotton layer.

[0008] Furthermore, the output ends of the carbon monoxide detector, the carbon dioxide detector, the oxygen detector, the upper pressure sensor, the lower pressure sensor and the magnetic flap level gauge are electrically connected to the input end of the PLC controller, and the output end of the PLC controller is connected to the coils of the combustible gas valve, the tap water inlet valve, the first sewage valve and the second sewage valve; The self-priming pump comprises a vacuum pump, the vacuum pump is connected to a frequency converter, and the frequency converter is communicatively connected to a PLC controller; The PLC controller is also communicatively connected to a host computer.

[0009] Combustible gas detection and gas filter device detection are achieved through carbon monoxide detector, carbon dioxide detector, oxygen detector, upper pressure sensor, lower pressure sensor and magnetic flap level gauge, and the gas filter device can be automatically operated in combination with PLC controller, self-priming pump, combustible gas valve, tap water inlet valve, first sewage valve and second sewage valve.

[0010] Furthermore, the combustible gas detection pipeline is a three-way pipe, and the other outlet of the combustible gas detection pipeline is connected to a hot air furnace. The three-way pipe is set so that part of the combustible gas enters the hot air furnace to provide heat energy for the gasification furnace, and part of the combustible gas enters the gas filtering device for detection.

[0011] The second aspect of the present invention provides an online detection method for combustible gas in a sludge pyrolysis gasification furnace, comprising: Step 1: The gasifier is running, and the PLC controller is used to open the tap water inlet valve, and water flows into the gas filter device. The liquid level of the gas filter device is detected by the magnetic flap level gauge; Step 2: The PLC controller closes the tap water inlet valve according to the liquid level of the gas filter device and opens the combustible gas valve. The PLC controller controls the self-priming pump to work through the frequency converter, and the combustible gas enters the gas filter device; Step 3: The combustible gas rises and passes through the water for the first filtration. The tar and dust in the combustible gas remain in the water. The combustible gas carries moisture into the activated carbon layer for the second filtration. The moisture in the combustible gas is adsorbed by the activated carbon layer. The combustible gas enters the filter cotton layer for the third filtration. The moisture and tar in the combustible gas are adsorbed by the filter cotton layer. Step 4: The combustible gas after three filtrations is discharged from the exhaust pipe and detected by a carbon monoxide detector, a carbon dioxide detector and an oxygen detector. The PLC controller receives the detection parameters of the carbon monoxide detector, the carbon dioxide detector and the oxygen detector, and controls the gasifier according to the detection parameters.

[0012] Furthermore, the step 2 further comprises: The PLC controller is set with a maximum water level threshold and a minimum water level threshold. When the magnetic flap level gauge detects that the liquid level of the gas filter device is higher than the maximum water level threshold, the PLC controller controls the tap water inlet valve to close and stop water injection; When the magnetic flap level gauge detects that the liquid level of the gas filter device is lower than the minimum water level threshold, the PLC controller controls the tap water inlet valve to open and inject water.

[0013] The water purification capacity is limited, and clean water needs to be refilled every once in a while. The minimum water level threshold and the maximum water level threshold are set. The PLC controller controls the tap water inlet valve according to the minimum water level threshold and the maximum water level threshold to realize automatic water injection control of the gas filter device.

[0014] Furthermore, the step 3 also includes: The PLC controller is provided with a pressure difference threshold between the upper and lower layers. If the difference between the detection values ​​of the lower pressure sensor and the upper pressure sensor is greater than the pressure difference threshold, the activated carbon layer and the filter cotton layer are replaced.

[0015] The activated carbon layer and the filter cotton layer have limited purification capabilities. Since the activated carbon layer is full of impurities, the combustible gas in the lower layer continues to enter the gas filter device, causing the pressure in the lower layer to continue to increase, and the activated carbon layer needs to be replaced. Similarly, if the pressure in the upper layer increases and exceeds the upper pressure threshold, the filter cotton layer needs to be replaced.

[0016] Furthermore, the step 4 also includes: If the oxygen content exceeds 5%, the PLC controller will control the gasifier to suffocate; If the carbon dioxide content exceeds 12%, the PLC controller will increase the temperature of the gasifier. If the carbon dioxide content is lower than 10%, the PLC controller will decrease the temperature of the gasifier.

[0017] If the oxygen content exceeds 5%, the PLC controller will execute the furnace suffocation operation to avoid explosion accidents.

[0018] The PLC controller controls the air volume or gas-steam ratio to keep the carbon dioxide content between 10% and 12%.

[0019] Furthermore, step 5 is also included, and step 5 includes: The PLC controller controls the first sewage valve to open so that the water with tar in the gas filter device is discharged from the upper sewage pipe; The PLC controller controls the second sewage valve to open, and the water containing tar and dust in the gas filtration device is discharged from the lower sewage pipe.

[0020] The gas filter device needs to be cleaned at regular intervals, and the PLC controller controls the first sewage valve and the second sewage valve to achieve sewage control.

[0021] Through the above technical solution, the beneficial effects of the present invention are: The present invention adds a gas filtering device. After the combustible gas enters the gas filtering device, it is filtered three times by water, an activated carbon layer and a filter cotton layer. Impurities such as tar, dust, and moisture in the combustible gas are removed by the water, the activated carbon layer and the filter cotton layer respectively. Therefore, it reduces pipeline blockage, avoids impurities clogging the sensor probe, reduces equipment failure rate, prolongs equipment service life, and improves gas detection accuracy.

[0022] The invention has a high degree of automation, and is provided with a PLC controller and a magnetic flap level gauge to detect the water level in the gas filter device, and is combined with a tap water inlet valve to realize automatic water replenishment; An upper pressure sensor and a lower pressure sensor are provided to provide a reminder for replacing the activated carbon layer and the filter cotton layer; Set up carbon monoxide detector, carbon dioxide detector and oxygen detector to detect the combustible gas after filtering; An online detection method for combustible gas in a sludge pyrolysis gasifier is used to realize intelligent control of the gasifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of an online detection system for combustible gas in a sludge pyrolysis gasification furnace according to the present invention; Figure 2 A flowchart of the steps of an online detection method for combustible gas in a sludge pyrolysis gasification furnace according to the present invention; Figure 3 The present invention discloses a circuit diagram of an online detection system for combustible gas in a sludge pyrolysis gasification furnace.

[0024] Figure numbers: 1 is a gasifier, 2 is a buffer silo, 3 is a blower, 4 is a gas filtering device, 5 is a combustible gas detection pipeline, 6 is a self-priming pump, 8 is a combustible gas valve, 9 is a tap water pipeline, 10 is a tap water inlet valve, 11 is an activated carbon layer, 12 is a filter cotton layer, 13 is an upper pressure sensor, 14 is a lower pressure sensor, 15 is an exhaust pipe, 17 is a carbon monoxide detector, 18 is a carbon dioxide detector, 19 is an oxygen detector, 20 is a magnetic flap level gauge, 21 is an upper sewage pipe, 22 is a first sewage valve, 23 is a lower sewage pipe, 24 is a second sewage valve, and 25 is a PLC controller. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments: Example 1 like Figures 1 to 3As shown, an online detection system for combustible gas in a sludge pyrolysis gasification furnace comprises a gasifier 1, a buffer silo 2 is arranged at the upper part of the gasifier 1, a blower 3 is arranged at the lower part of the gasifier 1, and a gas filter 4 is also included, a combustible gas detection pipeline 5 is arranged between the gas filter 4 and the gasifier 1, a self-priming pump 6 and a combustible gas valve 8 are arranged on the combustible gas detection pipeline 5 in sequence, the combustible gas detection pipeline 5 is connected with the bottom of the gas filter 4, a tap water pipeline 9 is arranged in the middle part of the gas filter 4, a tap water inlet valve 10 is arranged on the tap water pipeline 9, an activated carbon layer 11 and a filter cotton layer 12 are arranged in sequence from bottom to top at the upper position inside the gas filter 4, an upper pressure sensor 13 is arranged on the upper part of the filter cotton layer 12, a lower pressure sensor 14 is arranged on the lower part of the activated carbon layer 11, an exhaust pipeline 15 is arranged at the top of the gas filter 4, and a carbon monoxide detector 17, a carbon dioxide detector 18 and an oxygen detector 19 are arranged on the exhaust pipeline 15; A magnetic flap level gauge 20 and an upper sewage pipe 21 are provided in the middle of the gas filter device 4, and a first sewage valve 22 is provided on the upper sewage pipe 21. A lower sewage pipe 23 is provided at the bottom of the gas filter device 4, and a second sewage valve 24 is provided on the lower sewage pipe 23. The self-priming pump 6, combustible gas valve 8, tap water inlet valve 10, carbon monoxide detector 17, carbon dioxide detector 18, oxygen detector 19, upper pressure sensor 13, lower pressure sensor 14, first sewage valve 22, magnetic flap level gauge 20 and second sewage valve 24 are connected to a PLC controller 25.

[0026] The gas filtering device 4 comprises a furnace body and a furnace cover, wherein the furnace body and the furnace cover are flange-connected, and the activated carbon layer 11 and the filter cotton layer 12 are detachably connected to the inner side wall of the furnace body.

[0027] The output ends of the carbon monoxide detector 17, the carbon dioxide detector 18, the oxygen detector 19, the upper pressure sensor 13, the lower pressure sensor 14 and the magnetic flap level gauge 20 are electrically connected to the input end of the PLC controller 25, and the output end of the PLC controller 25 is connected to the coils of the combustible gas valve 8, the tap water inlet valve 10, the first sewage valve 22 and the second sewage valve 24; The self-priming pump 6 includes a vacuum pump, and the vacuum pump is connected to a frequency converter, and the frequency converter is communicatively connected to the PLC controller 25; The PLC controller 25 is also communicatively connected to a host computer.

[0028] The combustible gas detection pipeline 5 is a three-way pipe, and the other outlet of the combustible gas detection pipeline 5 is connected to a hot air furnace.

[0029] Example 2 Based on Example 1, when using a method for online detection of combustible gas in a sludge pyrolysis gasification furnace: Step 1: The PLC controller 25 controls the operation of the gasifier 1 , and then the PLC controller 25 energizes the coil of the tap water inlet valve 10 , the tap water inlet valve 10 opens, and the tap water enters the gas filter device 4 through the tap water pipe 9 , and the magnetic flap level meter 20 detects the internal liquid level of the gas filter device 4 .

[0030] Step 2: The PLC controller 25 is provided with a maximum water level threshold and a minimum water level threshold. When the magnetic flap level gauge 20 detects that the liquid level of the gas filter device 4 is higher than the maximum water level threshold, the PLC controller 25 controls the tap water inlet valve 10 to close and stop water injection; When the magnetic flap level gauge 20 detects that the liquid level of the gas filter device 4 is lower than the minimum water level threshold, the PLC controller 25 controls the tap water inlet valve 10 to open and inject water; The PLC controller 25 de-energizes the coil of the tap water inlet valve 10 according to the liquid level of the gas filter device 4, and the tap water inlet valve 10 is in a closed valve state, and water injection is stopped; The PLC controller 25 turns on the combustible gas valve 8 and opens it. The PLC controller 25 controls the self-priming pump 6 to work through the frequency converter, and the combustible gas is sucked into the gas filter device 4. The combustible gas detection pipeline 5 is a three-way pipe, and part of the combustible gas enters the hot air furnace.

[0031] Step 3: The combustible gas rises and passes through the water for the first filtration, and the tar and dust in the combustible gas remain in the water. The combustible gas carries moisture into the activated carbon layer 11 for the second filtration, and the moisture in the combustible gas is adsorbed by the activated carbon layer 11. The combustible gas enters the filter cotton layer 12 for the third filtration, and the moisture and tar in the combustible gas are adsorbed by the filter cotton layer.

[0032] Step 4: The combustible gas after three filtrations is discharged from the exhaust pipe 15 and detected by the carbon monoxide detector 17, the carbon dioxide detector 18 and the oxygen detector 19. The PLC controller 25 receives the detection parameters of the carbon monoxide detector 17, the carbon dioxide detector 18 and the oxygen detector 19; If the oxygen content exceeds 5%, the PLC controller 25 performs a suffocating control on the gasifier 1; If the carbon dioxide content exceeds 10%-12%, the PLC controller 25 adjusts the temperature of the gasifier 1.

[0033] Step 5: The PLC controller 25 powers on the first sewage valve 22 to open, and the water with tar in the gas filter device 4 is discharged from the upper sewage pipe 21; The PLC controller 25 energizes and opens the second sewage valve 24 , and the water containing tar and dust in the gas filter device 4 is discharged from the lower sewage pipe 23 .

[0034] The PLC controller 25 is provided with a pressure difference threshold between the upper and lower layers. If the difference between the detection values ​​of the lower pressure sensor 14 and the upper pressure sensor 13 is greater than the pressure difference threshold, the activated carbon layer 11 and the filter cotton layer 12 are replaced.

[0035] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made according to the structures, features and principles described in the patent scope of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. An online detection system for combustible gas in a sludge pyrolysis gasifier, comprising a gasifier (1), wherein a buffer silo (2) is disposed on the upper portion of the gasifier (1), and a blower (3) is disposed on the lower portion of the gasifier (1), characterized in that: It also comprises a gas filter device (4), wherein a combustible gas detection pipeline (5) is arranged between the gas filter device (4) and the gasifier (1), a self-priming pump (6) and a combustible gas valve (8) are arranged on the combustible gas detection pipeline (5) in sequence, the combustible gas detection pipeline (5) is communicated with the bottom of the gas filter device (4), a tap water pipeline (9) is arranged in the middle of the gas filter device (4), a tap water inlet valve (10) is arranged on the tap water pipeline (9), an activated carbon layer (11) and a filter cotton layer (12) are arranged in sequence from bottom to top in the gas filter device (4) at the upper position inside, an upper pressure sensor (13) is arranged on the upper part of the filter cotton layer (12), and a lower pressure sensor (14) is arranged on the lower part of the activated carbon layer (11), and an exhaust pipeline (15) is arranged at the top of the gas filter device (4), and a carbon monoxide detector (17), a carbon dioxide detector (18) and an oxygen detector (19) are arranged on the exhaust pipeline (15); A magnetic flap level gauge (20) and an upper sewage pipe (21) are provided in the middle of the gas filter device (4), a first sewage valve (22) is provided on the upper sewage pipe (21), and a lower sewage pipe (23) is provided at the bottom of the gas filter device (4), a second sewage valve (24) is provided on the lower sewage pipe (23); The self-priming pump (6), the combustible gas valve (8), the tap water inlet valve (10), the carbon monoxide detector (17), the carbon dioxide detector (18), the oxygen detector (19), the upper pressure sensor (13), the lower pressure sensor (14), the first sewage discharge valve (22), the magnetic flap liquid level gauge (20) and the second sewage discharge valve (24) are connected to a PLC controller (25).

2. The on-line detection system for combustible gas in a sludge pyrolysis gasification furnace according to claim 1 is characterized in that: The gas filtering device (4) comprises a furnace body and a furnace cover, wherein the furnace body and the furnace cover are flange-connected, and the activated carbon layer (11) and the filter cotton layer (12) are detachably connected to the inner wall of the furnace body.

3. The on-line detection system for combustible gas in a sludge pyrolysis gasification furnace according to claim 1 is characterized in that: The output ends of the carbon monoxide detector (17), the carbon dioxide detector (18), the oxygen detector (19), the upper pressure sensor (13), the lower pressure sensor (14) and the magnetic flap level gauge (20) are electrically connected to the input end of the PLC controller (25); the output end of the PLC controller (25) is connected to the coils of the combustible gas valve (8), the tap water inlet valve (10), the first sewage valve (22) and the second sewage valve (24); The self-priming pump (6) comprises a vacuum pump, the vacuum pump is connected to a frequency converter, and the frequency converter is communicatively connected to a PLC controller (25); The PLC controller (25) is also communicatively connected to a host computer.

4. The on-line detection system for combustible gas in a sludge pyrolysis gasification furnace according to claim 1 is characterized in that: The combustible gas detection pipeline (5) is a three-way pipe, and the other outlet of the combustible gas detection pipeline (5) is connected to a hot air furnace.

5. The method for online detection of combustible gas in a sludge pyrolysis gasification furnace (1) of the online detection system of combustible gas in a sludge pyrolysis gasification furnace according to any one of claims 1 to 4 comprises: Step 1: The gasifier (1) is running, and the tap water inlet valve (10) is opened using the PLC controller (25), so that water flows into the gas filter device (4), and the liquid level of the gas filter device (4) is detected by the magnetic flap liquid level meter (20); Step 2: The PLC controller (25) closes the tap water inlet valve (10) according to the liquid level of the gas filter device (4) and opens the combustible gas valve (8). The PLC controller (25) controls the self-priming pump (6) to work through the frequency converter, and the combustible gas enters the gas filter device (4). Step 3: The combustible gas rises and passes through the water for the first filtration, and the tar and dust in the combustible gas remain in the water. The combustible gas carries water and enters the activated carbon layer (11) for the second filtration, and the water in the combustible gas is adsorbed by the activated carbon layer (11). The combustible gas enters the filter cotton layer (12) for the third filtration, and the water and tar in the combustible gas are adsorbed by the filter cotton layer; Step 4: The combustible gas after three filtrations is discharged from the exhaust pipe (15) and detected by the carbon monoxide detector (17), the carbon dioxide detector (18) and the oxygen detector (19). The PLC controller (25) receives the detection parameters of the carbon monoxide detector (17), the carbon dioxide detector (18) and the oxygen detector (19), and the PLC controller (25) controls the gasifier (1) according to the detection parameters.

6. The system and method for online detection of combustible gas in a sludge pyrolysis gasification furnace according to claim 5, characterized in that: The step 2 also includes: The PLC controller (25) is provided with a maximum water level threshold and a minimum water level threshold. When the magnetic flap level gauge (20) detects that the liquid level of the gas filter device (4) is higher than the maximum water level threshold, the PLC controller (25) controls the tap water inlet valve (10) to close and stop water injection; When the magnetic flap liquid level meter (20) detects that the liquid level of the gas filter device (4) is lower than the minimum water level threshold, the PLC controller (25) controls the tap water inlet valve (10) to open and perform water injection.

7. The system and method for online detection of combustible gas in a sludge pyrolysis gasification furnace according to claim 5, characterized in that: The step 3 also includes: The PLC controller (25) is provided with a pressure difference threshold between the upper and lower layers. If the difference between the detection values ​​of the lower layer pressure sensor (14) and the upper layer pressure sensor (13) is greater than the pressure difference threshold, the activated carbon layer (11) and the filter cotton layer (12) are replaced.

8. The system and method for online detection of combustible gas in a sludge pyrolysis gasification furnace according to claim 5, characterized in that: The step 4 also includes: If the oxygen content exceeds 5%, the PLC controller (25) controls the gasifier (1) to suffocate; If the detected carbon dioxide content exceeds 10% to 12%, the PLC controller (25) adjusts the temperature of the gasifier (1).

9. The system and method for online detection of combustible gas in a sludge pyrolysis gasification furnace according to claim 5, characterized in that: The invention also includes step 5, wherein step 5 includes: The PLC controller (25) controls the first sewage valve (22) to open so that the water containing tar in the gas filter device (4) is discharged from the upper sewage pipe (21); The PLC controller (25) controls the second sewage valve (24) to open, and the water containing tar and dust in the gas filtering device (4) is discharged from the lower sewage pipe (23).

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