A waste gas treatment system for a wood heat treatment kiln

Abstract

This utility model discloses a waste gas treatment system for a wood heat treatment kiln, including a water bath spray dust collector and a cooling adsorption filter connected sequentially to the kiln's waste gas discharge pipe. The water bath spray dust collector includes a sealed water bath tank, with water bath heads connected to the kiln's waste gas discharge pipe inside the tank. Spray heads inside the tank spray water from the top onto the water seal liquid surface. The spray heads are connected to the lower part of the water bath tank via a spray circulation pipe and a spray circulation pump. An overflow pipe for controlling the water seal liquid level is also provided inside the water bath tank. A water replenishment tank for automatically replenishing water into the water bath tank is located outside the tank. A water bath exhaust pipe at the top of the water bath tank transports the water bath-treated waste gas to the cooling adsorption filter. This waste gas treatment system not only improves the capture efficiency of particulate matter in the waste gas but also effectively treats volatile and soluble components in the waste gas, reducing the environmental impact of the waste gas.

Description

Technical Field

[0001] This utility model relates to a waste gas treatment system, and more particularly to a waste gas treatment system for purifying waste gas discharged from a wood heat treatment kiln. Background Technology

[0002] The heat treatment of wood using a wood heat treatment kiln generates a large amount of waste gas. This waste gas contains not only particulate matter such as sawdust and dust, but also VOCs, formic acid, acetic acid, and propionic acid. Direct emission into the atmosphere will pollute the environment. CN 208375518 U discloses a wood heat treatment device, which is an early product of the applicant, and specifically discloses the exhaust purification system of the wood heat treatment device. The exhaust purification system includes a water seal dust collector, which captures particulate matter in the waste gas. At the same time, some water-soluble substances also dissolve in the water, reducing the pollution caused by waste gas emissions. However, in actual production, the temperature of the gas discharged from the wood heat treatment kiln can reach up to 200 degrees Celsius. When the high-temperature gas comes into contact with water in the water seal dust collector, it will instantly generate a large amount of steam. When the large amount of steam is quickly discharged from the water seal dust collector, it will carry a small amount of particulate matter, resulting in a small amount of particulate matter remaining in the exhaust gas. In addition, this high-temperature and high-humidity exhaust gas will reduce the adsorption effect of activated carbon, causing some volatile and soluble components to be unable to be adsorbed by activated carbon, so that the exhaust gas will still cause a certain degree of pollution to the environment. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a waste gas treatment system for a wood heat treatment kiln. This waste gas treatment system can not only improve the capture efficiency of particulate matter in the waste gas, but also effectively treat the volatile and soluble components in the waste gas, thereby reducing the impact of the waste gas on the environment.

[0004] The technical solution adopted to solve the technical problem is as follows: A waste gas treatment system for a wood heat treatment kiln, comprising a water bath spray dust collector and a cooling adsorption filter connected sequentially to the kiln's waste gas discharge pipe. The water bath spray dust collector includes a sealed water bath tank, with water bath heads connected to the kiln's waste gas discharge pipe inside the water bath tank. Spray heads are also installed inside the water bath tank, spraying water from the top onto the water seal liquid surface. The spray heads are connected to the lower part of the water bath tank via a spray circulation pipe and a spray circulation pump. A control system is also installed inside the water bath tank. An overflow pipe is installed at the height of the water seal liquid level. The air outlet of the water bath head is lower than the water seal liquid level. An automatic water replenishment tank is installed outside the water bath to replenish water into the water bath. The bottom of the water replenishment tank is connected to the lower part of the water bath through a water replenishment pipe. A one-way valve is installed on the water replenishment pipe to prevent water in the water bath from flowing back into the water replenishment tank. A tap water pipe is connected to the water replenishment tank to supply water. A float valve is installed at the end of the tap water pipe. A water bath exhaust pipe is installed at the top of the water bath to transport the waste gas treated by the water bath spray to the cooling adsorption filter.

[0005] As a further improvement of this utility model: the cooling adsorption filter includes a cooling tank body, an upper tube sheet and a lower tube sheet that are sealed to the inner wall of the tank body, a vertically arranged heat exchange tube bundle between the upper tube sheet and the lower tube sheet, the cooling tank body above the upper tube sheet is connected to a water bath exhaust pipe, the cooling tank body below the lower tube sheet is connected to a cooling exhaust pipe, the cooling tank body between the upper tube sheet and the lower tube sheet is connected to a cooling circulating water inlet pipe and a cooling circulating water outlet pipe, the cooling circulating water inlet pipe and the cooling circulating water outlet pipe are connected to a cooling water tank through a cooling circulating pump to form a shell-side cooling circulation loop, and the cooling exhaust pipe is connected to an vent pipe through an activated carbon filter pipe.

[0006] As a further improvement of this utility model: a condensate drain pipe is provided at the bottom of the cooling tank, a condensate treatment tank is provided outside the cooling tank to receive the condensate discharged from the condensate drain pipe, and a condensate drain valve is provided on the condensate drain pipe.

[0007] As a further improvement of this utility model: a sealed water tank is provided at the lower end of the overflow pipe to prevent the exhaust gas in the water bath from being discharged from the overflow pipe.

[0008] As a further improvement of this utility model: a negative pressure valve is connected to the kiln exhaust pipe to prevent water in the water bath from being sucked into the kiln during the kiln cooling process.

[0009] As a further improvement of this utility model: the water bath head is a shower-style jet head with the air outlet facing downwards.

[0010] Beneficial effects: In the exhaust gas treatment system of the wood heat treatment kiln of this utility model, due to the technical feature of having a spray head in the water bath tank that sprays water from the top onto the water seal liquid surface, and the air outlet of the water bath head being lower than the water seal liquid surface, during the process of exhaust gas discharged from the water bath head contacting the water, some of the particulate matter entrained in it is captured by the water, and some soluble components dissolve in the water. The residual exhaust gas and steam flow upward together and enter the water bath exhaust pipe. The water sprayed from the spray head contacts the rising airflow in the opposite direction, which not only reduces the airflow temperature and the amount of steam discharged, but also allows for secondary capture of particulate matter and secondary dissolution of soluble components. This results in a better exhaust gas purification effect than water seal dust removal devices without spray function. By employing an overflow pipe inside the water bath to control the water seal level, and an automatic water replenishment tank outside the water bath to replenish water to the water bath, with the bottom of the water replenishment tank connected to the lower part of the water bath via a water replenishment pipe, and a one-way valve on the water replenishment pipe to prevent water from the water bath from flowing back into the water replenishment tank, and a tap water pipe connected to the water replenishment tank with a float valve at the end of the tap water pipe, this system achieves automatic discharge of hot water and automatic replenishment of cold water from the water bath. Furthermore, this water replenishment method is less affected by fluctuations in the water seal level inside the water bath, resulting in more stable water replenishment, ensuring the cooling effect of the spray on the steam, reducing the steam flow rate, and enabling better purification of the exhaust gas. Because the cooling adsorption filter employs a cooling tank, with an upper tube sheet and a lower tube sheet sealed to the inner wall of the tank, and a vertically arranged heat exchange tube bundle between the upper and lower tube sheets, the cooling tank above the upper tube sheet is connected to a water bath exhaust pipe, and the cooling tank below the lower tube sheet is connected to a cooling exhaust pipe. A cooling circulating water inlet pipe and a cooling circulating water outlet pipe are connected to the cooling tank between the upper and lower tube sheets. The cooling circulating water inlet pipe and the cooling circulating water outlet pipe are connected to a cooling water tank via a cooling circulating pump to form a shell-side cooling circulation loop. The technical feature of connecting the cooling exhaust pipe to the vent pipe via an activated carbon filter tube ensures that the exhaust gas and steam are fully cooled as they pass through the heat exchange tube bundle. The steam and some volatile components condense into a liquid state. After cooling, the exhaust gas is then adsorbed by the activated carbon filter tube, allowing for the full adsorption of harmful components and significantly reducing pollutant residues in the final discharged exhaust gas. The adoption of a condensate drain pipe at the bottom of the cooling tank, a condensate treatment tank outside the cooling tank to receive the condensate drained from the pipe, and a condensate drain valve on the drain pipe facilitates centralized and harmless treatment of the pollutant-containing wastewater obtained from condensation, further reducing environmental impact. Furthermore, the inclusion of a sealed water tank at the lower end of the overflow pipe to prevent exhaust gas from escaping through the overflow pipe, while maintaining the water seal level, prevents gas from the water bath from directly escaping through the overflow pipe and polluting the air.The inclusion of a negative pressure valve on the kiln exhaust pipe to prevent water from the water bath from being drawn into the kiln during cooling ensures that water from the water bath is not backflowed into the kiln due to internal negative pressure during the cooling phase. Furthermore, the use of a shower-style jet nozzle with a downward-facing outlet in the water bath design allows for more thorough contact between the exhaust gas and water, resulting in less impact on the water and reduced fluctuations in the water seal surface. Attached Figure Description

[0011] The exhaust gas treatment system of the wood heat treatment kiln of this utility model will be further described in detail below with reference to the accompanying drawings.

[0012] Figure 1 This is a schematic diagram illustrating the working principle of the exhaust gas treatment system for the wood heat treatment kiln of this utility model. Detailed Implementation

[0013] like Figure 1 As shown, the exhaust gas treatment system of the wood heat treatment kiln of this utility model includes a water bath spray dust collector a and a cooling adsorption filter b, which are sequentially connected to the exhaust gas discharge pipe of the kiln body.

[0014] The water bath spray dust collector includes a sealed water bath tank 9, a water bath head 6 connected to the kiln exhaust pipe 7 inside the water bath tank, a spray head 10 spraying water from the top onto the water seal liquid surface inside the water bath tank, the spray head being connected to the lower part of the water bath tank via a spray circulation pipe 13 and a spray circulation pump 14, an overflow pipe 11 controlling the height of the water seal liquid level inside the water bath tank, the air outlet of the water bath head being lower than the water seal liquid level, a water replenishment tank 3 automatically replenishing water into the water bath tank outside the water bath tank, the bottom of the water replenishment tank being connected to the lower part of the water bath tank via a water replenishment pipe 1, a one-way valve 2 preventing water from the water bath tank from flowing back into the water replenishment tank on the water replenishment pipe, a tap water pipe 4 supplying water to the water replenishment tank, a float valve 5 at the end of the tap water pipe, and a water bath exhaust pipe 12 at the top of the water bath tank for transporting the waste gas treated by the water bath spray to the cooling adsorption filter.

[0015] Preferably, a sealed water tank 29 is provided at the lower end of the overflow pipe to prevent exhaust gas in the water bath from being discharged through the overflow pipe.

[0016] Preferably, a negative pressure valve 8 is connected to the kiln exhaust pipe to prevent water from the water bath tank from being sucked into the kiln during the kiln cooling process.

[0017] In the heat treatment of wood, heating is usually carried out in stages, and the waste gas generated is discharged in stages. The water in the water bath expands in volume after being heated by the waste gas, causing the water seal liquid level to rise. Since there is a one-way valve on the water supply pipe, some water is discharged from the water bath through the overflow pipe. When the waste gas in one stage is discharged, the water in the water bath cools down and shrinks in volume, causing the water seal liquid level to drop. At this time, the water supply tank will automatically replenish cold water into the water bath, thereby realizing the automatic replenishment of cold water into the water bath.

[0018] Preferably, the water bath head is a shower-style jet head with the air outlet facing downwards.

[0019] The cooling adsorption filter includes a cooling tank 21, with an upper tube sheet 20 and a lower tube sheet 22 sealed to the inner wall of the tank. A vertically arranged heat exchange tube bundle 19 is provided between the upper and lower tube sheets. The cooling tank above the upper tube sheet is connected to a water bath exhaust pipe, and the cooling tank below the lower tube sheet is connected to a cooling exhaust pipe. The cooling tank between the upper and lower tube sheets is connected to a cooling circulating water inlet pipe 18 and a cooling circulating water outlet pipe 16. The cooling circulating water inlet pipe and the cooling circulating water outlet pipe are connected to a cooling water tank 15 through a cooling circulating pump 17 to form a shell-side cooling circulation loop. The cooling exhaust pipe is connected to an vent pipe 23 through an activated carbon filter pipe 24.

[0020] Preferably, a condensate drain pipe 26 is provided at the bottom of the cooling tank, a condensate treatment tank 27 is provided outside the cooling tank to receive the condensate drain pipe, a condensate drain valve 25 is provided on the condensate drain pipe, and a level gauge 28 is provided on the outer wall of the cooling tank below the lower tube sheet.

[0021] During operation, the exhaust gas treatment system of this wood heat treatment kiln utilizes a spray circulation pump to continuously pump cold water from the lower part of the kiln body to the spray heads, creating a water spray pattern within the water bath that flows in the opposite direction to the airflow. A cooling circulation pump circulates water from the cooling water tank between the heat exchange tubes that form the heat exchange tube bundle, cooling the bundle. The high-temperature exhaust gas from the wood heat treatment kiln is discharged into the water below the water seal surface through the kiln exhaust pipe and the water bath heads. Most particulate matter and soluble components are captured by the water in the water bath. The water vapor formed by the high-temperature exhaust gas and water is sprayed upwards, cooled, and then enters the cooling adsorption filter. As it flows through the heat exchange tubes that form the heat exchange tube bundle, it is condensed and cooled. Some volatile components, along with the vapor, are condensed into a liquid that cannot be discharged in a gaseous state. The remaining exhaust gas is purified by activated carbon filtration before being released into the atmosphere, thus reducing the environmental pollution and impact of exhaust gas generated during wood heat treatment.

Claims

1. A waste gas treatment system of a wood heat treatment kiln, comprising a water bath spray dust remover and a cooling adsorption filter connected in sequence with a kiln body waste gas discharge pipe, the water bath spray dust remover comprising a closed water bath barrel body, a water bath head connected with the kiln body waste gas discharge pipe being arranged in the water bath barrel body, characterized in that: The water bath is equipped with a spray head that sprays water from the top onto the water seal liquid surface. The spray head is connected to the lower part of the water bath through a spray circulation pipe and a spray circulation pump. An overflow pipe that controls the height of the water seal liquid level is also provided inside the water bath. The air outlet of the water bath head is lower than the water seal liquid level. An automatic water replenishment tank is provided outside the water bath to replenish water into the water bath. The bottom of the water replenishment tank is connected to the lower part of the water bath through a water replenishment pipe. A one-way valve is provided on the water replenishment pipe to prevent water from the water bath from flowing back into the water replenishment tank. A tap water pipe is connected to the water replenishment tank to supply water. A float valve is provided at the end of the tap water pipe. A water bath exhaust pipe is provided at the top of the water bath to transport the waste gas treated by the water bath spray to the cooling adsorption filter. ​ 2. The exhaust gas treatment system of a wood heat treatment kiln according to claim 1, characterized in that: The cooling adsorption filter includes a cooling tank, inside which are an upper tube sheet and a lower tube sheet that are sealed to the inner wall of the tank. A vertically arranged heat exchange tube bundle is provided between the upper and lower tube sheets. The cooling tank above the upper tube sheet is connected to a water bath exhaust pipe, and the cooling tank below the lower tube sheet is connected to a cooling exhaust pipe. The cooling tank between the upper and lower tube sheets is connected to a cooling circulating water inlet pipe and a cooling circulating water outlet pipe. The cooling circulating water inlet pipe and the cooling circulating water outlet pipe are connected to a cooling water tank through a cooling circulating pump to form a shell-side cooling circulation loop. The cooling exhaust pipe is connected to an vent pipe through an activated carbon filter pipe.

3. The exhaust gas treatment system of a wood heat treatment kiln according to claim 2, characterized in that: A condensate drain pipe is provided at the bottom of the cooling tank, and a condensate treatment tank is provided outside the cooling tank to receive the condensate discharged from the condensate drain pipe. A condensate drain valve is provided on the condensate drain pipe.

4. The exhaust gas treatment system of a wood heat treatment kiln according to claim 3, characterized in that: A sealed water tank is provided at the lower end of the overflow pipe to prevent exhaust gas from the water bath from being discharged through the overflow pipe.

5. The exhaust gas treatment system of a wood heat treatment kiln according to any one of claims 1 to 4, characterized in that: A negative pressure valve is installed on the kiln exhaust pipe to prevent water from the water bath tank from being sucked into the kiln during the kiln cooling process.

6. The exhaust gas treatment system of a wood heat treatment kiln according to claim 5, characterized in that: The water shower head is a shower-style jet head with the air outlet pointing downwards.

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