A set shaping machine exhaust waste heat recovery purification integrated device

Abstract

The application belongs to the technical field of textile printing and dyeing environmental protection equipment, and particularly relates to a setting machine waste gas waste heat recovery and purification integrated device. The device comprises a filtering device, a gas-gas waste heat recovery device, a gas-water heat exchanger, an electrostatic purification device and an exhaust fan. The gas-gas waste heat recovery device comprises a waste gas flow channel and a fresh air flow channel. High-temperature waste gas discharged by the setting machine flows in the waste gas flow channel, and fresh air from the outside flows in the fresh air flow channel after entering the fresh air inlet. The two heat exchange through the heat exchange wall surface, and the preheated fresh air after heat exchange is sent back to the setting machine oven. The gas-water heat exchanger is arranged between the gas-gas waste heat recovery device and the electrostatic purification device, and is used for further filtering and cooling treatment of the cooled waste gas. The electrostatic purification device is used for adsorbing oil fume and small particles in the waste gas. Large heat can be transferred under small temperature difference, the recovered heat is used for preheating fresh air, the energy consumption of the setting machine heating gas is greatly reduced, and the operation cost of the enterprise is reduced.

Description

[Technical Field] This application belongs to the technical field of textile printing and dyeing environmental protection equipment, specifically relating to an integrated device for waste heat recovery and purification of waste gas from a stenter. [Background Technology] Setting machines are crucial equipment in the textile printing and dyeing industry. Their working principle involves heating ambient air to 150°C-200°C and circulating it within the machine to dry and set fabrics. During this process, synthetic chemicals within the fabric decompose under heat, generating waste heat containing large amounts of oil fumes, water vapor, and the odor of chemical dyes. Currently, traditional waste gas treatment equipment fails to effectively recover the high-temperature heat energy in the waste gas, resulting in direct emissions. This leads to high energy consumption in setting machines, heat pollution around the factory, and non-compliance with low-carbon emission standards. Traditional equipment lacks efficient pre-treatment, easily causing back-end blockages; it lacks automatic cleaning functions, requiring significant manual maintenance and resulting in a high failure rate. Furthermore, it lacks efficient methods for removing large amounts of dust, fibers, and waxes carried in the waste gas, affecting subsequent heat recovery efficiency. [Utility Model Content] The purpose of this invention is to provide an integrated device for waste heat recovery and purification of waste gas from a stenter, which aims to solve the problems of high energy consumption, low purification efficiency and difficult maintenance of existing equipment through filtration devices, gas-to-gas heat recovery and multi-stage purification technology.

[0001] This application is achieved through the following technical solution: An integrated device for waste heat recovery and purification of waste gas from a stenter includes: a filter device, a gas-to-gas waste heat recovery device, a gas-to-water heat exchanger, an electrostatic purification device, and an exhaust fan connected sequentially along the direction of waste gas flow. The gas-to-gas waste heat recovery device includes an exhaust gas flow channel and a fresh air flow channel. The high-temperature exhaust gas discharged from the stenter flows in the exhaust gas flow channel, and the outside fresh air flows in the fresh air flow channel. The two exchange heat through the heat exchange wall. The preheated fresh air after heat exchange is returned to the stenter oven. The gas-water heat exchanger is located between the gas-gas waste heat recovery device and the electrostatic purification device, and is used to further filter and cool the cooled waste gas. The electrostatic purification device is used to adsorb oil fumes and fine particles in the exhaust gas.

[0002] The integrated waste heat recovery and purification device for stenter exhaust gas as described above also includes an oil-water separation device, which is connected to the drain outlets of the gas-water heat exchanger and the electrostatic purification device, respectively, for collecting waste oil and separating clean water for recycling.

[0003] As described above, in the integrated waste heat recovery and purification device for stenter exhaust gas, the filter device is located at the exhaust gas inlet and is a mechanical bar filter or an ultrasonic cleaning filter, used to intercept large particles of dust and fibers in the exhaust gas.

[0004] The above-mentioned integrated waste heat recovery and purification device for stenter exhaust gas adopts a plate heat exchanger structure and has several heat-conducting plates inside. The heat-conducting plates divide the inside of the device into an isolated exhaust gas layer and a fresh air layer. The heat-conducting plates are made of 316L stainless steel or ND steel.

[0005] As described above, in the integrated waste heat recovery and purification device for the waste gas of the stenter, the air inlet of the fresh air duct is connected to the outside air, and the air outlet of the fresh air duct is connected to a heat compensation fan. The heat compensation fan discharges the preheated fresh air into the oven of the stenter to maintain heat balance.

[0006] The above-described integrated waste heat recovery and purification device for stenter exhaust gas includes a gas-water heat exchanger comprising a spray zone and a dehydration zone. The spray zone is equipped with several sets of high-pressure nozzles for spraying atomized water vapor to contact the exhaust gas. The dehydration zone is located behind the spray zone and is equipped with a mechanical demister or a wire mesh demister to remove fine water droplets carried in the exhaust gas.

[0007] As described above, the integrated device for waste heat recovery and purification of waste gas from a stenter includes a high-voltage electrostatic module and an oil receiving tray. When the high-voltage electrostatic module is energized, it adsorbs oil in the flue gas and causes it to condense. The condensed oil then flows into the oil receiving tray.

[0008] As described above, the integrated device for waste heat recovery and purification of waste gas from a stenter includes an automatic spray cleaning device inside the electrostatic purification device. The automatic spray cleaning device sprays and cleans the high-voltage electrostatic module at set intervals according to a preset program.

[0009] As described above, in the integrated waste heat recovery and purification device for stenter exhaust gas, the wastewater and oil generated by the gas-water heat exchanger and the electrostatic purification device are fed into the oil-water separation device for separation. The separated clean water is treated and then sent back to the automatic spray cleaning device and / or the gas-water heat exchanger for recycling.

[0010] Compared with the prior art, this application has the following advantages: 1. The air-to-air waste heat recovery device utilizes hot plate technology, which has low heat transfer resistance and can transfer a large amount of heat under a small temperature difference. The recovered heat is used to preheat fresh air, which greatly reduces the energy consumption of the heating gas in the stenter and lowers the company's operating costs.

[0011] 2. An ultrasonic cleaning device is introduced as a pretreatment to effectively remove dust, oil and wax, and prevent heat exchanger blockage; combined with the electrostatic purification at the back end, it achieves deep removal of oil fumes, water vapor and particulate matter.

[0012] 3. Equipped with an automatic spray cleaning system and oil-water separation device, it realizes automatic maintenance of equipment and recycling of wastewater, reduces manual maintenance costs, and avoids secondary pollution.

[0013] 4. It solved the problem of exhaust gas pollution and also effectively reduced the temperature of the factory and its surroundings through heat recovery, thus improving the working environment for workers. [Attached Image Description] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a three-dimensional embodiment of the present application. Figure 1 ; Figure 2 This is a three-dimensional embodiment of the present application. Figure 2 ; Figure 3 yes Figure 1 The main view; Figure 4 yes Figure 3 Internal structure diagram; Figure 5 yes Figure 4 A three-dimensional perspective view of an oil-water separation unit; Figure 6 yes Figure 5 The main view; Figure 7 This is a schematic diagram of the flow of exhaust gas and fresh air in an embodiment of this application.

Detailed Implementation Methods

[0015] Please see Figures 1 to 7 An integrated device for waste heat recovery and purification of waste gas from a shaping machine includes: a filter device 1, a gas-to-gas waste heat recovery device 2, a gas-to-water heat exchanger 3, an electrostatic purification device 4, and an exhaust fan 5, which are connected sequentially along the direction of waste gas flow. The gas-to-gas waste heat recovery device 2 includes a waste gas flow channel 21 and a fresh air flow channel 22. The high-temperature waste gas discharged from the stenter flows in the waste gas flow channel 21, and the outside fresh air enters from the fresh air inlet 500 and flows in the fresh air flow channel. The two exchange heat through the heat exchange wall, and the preheated fresh air after heat exchange is returned to the stenter oven. The gas-water heat exchanger 3 is located between the gas-gas waste heat recovery device 2 and the electrostatic purification device 4, and is used to further filter and cool the cooled waste gas. The electrostatic purification device 4 is used to adsorb oil fumes and fine particles in the exhaust gas.

[0016] In this embodiment, an integrated design achieves efficient treatment and energy recycling of the stenter exhaust gas. In terms of working principle, the 150℃-200℃ high-temperature oily exhaust gas discharged from the stenter first passes through a filtration device, preferably an ultrasonic cleaning filter, which utilizes cavitation to effectively strip and intercept dust and oil in the exhaust gas, preventing blockage of subsequent equipment. The exhaust gas then enters a gas-to-gas waste heat recovery device, utilizing an internal high-efficiency superconducting heat plate (material can be 316L stainless steel or ND steel) to rapidly transfer heat to the outside fresh air in the fresh air duct. The preheated fresh air after heat exchange is returned to the stenter oven by a heat compensation fan, achieving significant energy savings and reducing the workshop ambient temperature. The cooled exhaust gas then enters a gas-to-water heat exchanger, such as a spray washing and cooling device, where water mist further washes away particulate matter and lowers the exhaust gas temperature to a suitable level for electrostatic attraction. The attached 60℃-80℃ safety range eliminates fire hazards; finally, the exhaust gas enters the electrostatic purification device, where oil fumes and VOCs are adsorbed and condensed under the action of a high-voltage electric field and flow into the oil receiving pan, and the purified gas meets emission standards; the beneficial effects of this solution are significant, not only maximizing heat recovery and reducing operating costs through dual heat exchange of "gas-gas" and "gas-water", but also solving the pain points of traditional equipment being prone to clogging and difficult to maintain through front-end ultrasonic cleaning and back-end automatic maintenance; other possible embodiments include designing the electrostatic purification device with a honeycomb conductive stainless steel anode tube bundle structure to improve demisting efficiency, or adopting an elastic design in the gas-gas waste heat recovery device to overcome high-temperature thermal expansion stress, and adding an intelligent control system to monitor the exhaust temperature in real time and link it with the fire sprinkler pipe 300, thereby ensuring the safe and stable operation of the device under different working conditions.

[0017] Furthermore, as a preferred embodiment of this solution and not a limitation, it also includes an oil-water separation device 6, which is connected to the drain outlets of the gas-water heat exchanger 3 and the electrostatic purification device 4, respectively, for collecting waste oil and separating clean water for recycling.

[0018] In this embodiment, the oil-water separator 6, as a key component for resource recycling in this system, is sealed to the bottom drain outlets of the gas-water heat exchanger 3 and the electrostatic purification device 4 via a drainage pipe 100. Its working principle is primarily based on shallow sedimentation theory and countercurrent flow separation principle, employing a composite separation technology combining gravity, biochemical methods, and mechanical gaps. When the hot wastewater generated by the spray washing of the gas-water heat exchanger 3 and the oily wastewater generated by the automatic cleaning of the electrostatic purification device 4 flow into this device, the unique internal flow channel design transforms the water flow from turbulent to laminar flow, significantly reducing the flow velocity. Automatic stratification is achieved by utilizing the density differences between oil, water, and impurities. The floating oil and wax are efficiently scraped off by the built-in automatic oil and wax skimming system and oil-collecting water-separating device and collected in a waste oil recovery tank. The settled solid particles accumulate in the sedimentation zone and are periodically cleaned, while the clear water in the middle layer is buffered and treated by multiple buffer tanks. After filtration, the water is pumped back to the air-water heat exchanger 3 via the spray cleaning pipe 200 for spray cooling or returned to the electrostatic purification device 4 for plate cleaning. The beneficial effect of this device is that it constructs a closed-loop system of "sewage-separation-reuse", which not only recovers economically valuable waste oil, but also realizes the recycling of process water, significantly reducing the consumption of fresh water and the amount of sewage discharged. The built-in buffer tank design can effectively cope with the impact of the spray water falling back during start-up and shutdown, ensuring the stable operation of the system. In other possible embodiments, in order to ensure the best separation efficiency, the device can be designed with a matching heat dissipation structure to control the temperature of the incoming water below 60°C. The main structure can be made of corrosion-resistant SUS201 or 304 stainless steel, and the effective volume (e.g., 3.0m³) can be adjusted according to the actual processing capacity requirements, or multiple precision filters can be added to prevent fine fibers from clogging the nozzles.

[0019] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the filter device 1 is disposed at the exhaust gas inlet end 400 and is a mechanical bar filter or an ultrasonic cleaning filter, used to intercept large particles of dust and fibers in the exhaust gas.

[0020] In this embodiment, the filter device 1 is located at the exhaust gas inlet. It primarily utilizes physical interception or ultrasonic cavitation cleaning technology to pre-remove large particles of fiber, dust, and sticky oil and wax carried in the 150℃-200℃ high-temperature exhaust gas discharged from the stenter, preventing them from entering subsequent equipment and causing blockages. Its working principle is that, if a mechanical grille is used, large particles of impurities are blocked through the physical pores of the filter structure. In contrast, the ultrasonic cleaning filter, as a preferred embodiment, utilizes the cavitation effect generated by the ultrasonic generator to forcefully peel off and crush the oil, wax, and fibers attached to the filter screen or suspended in the exhaust gas. This effectively solves the problems of easy clogging, lack of automatic cleaning function, high maintenance requirements, and high failure rate associated with traditional filtration equipment. The beneficial effects of this device are significant. As the first line of defense in the system, it not only greatly reduces the frequency of manual cleaning and maintenance, but more importantly, it protects the downstream gas-to-gas waste heat recovery device and gas-to-water heat exchanger from the effects of oil and dust accumulation. This ensures that the heat exchanger can always maintain a high heat transfer coefficient and low wind resistance, thereby improving the heat recovery efficiency and purification stability of the entire system. In other possible embodiments, the device can also be designed as a composite structure combining mechanical filtration and ultrasonic cleaning, or, depending on the different oil and wax contents in the exhaust gas, as a multi-stage filter mesh structure. It can also be equipped with a differential pressure sensor to monitor the blockage in real time and trigger the cleaning program, thereby adapting to different concentrations of pollutants generated by different shaping processes.

[0021] Furthermore, as a preferred embodiment of this solution and not a limitation, the gas-to-gas waste heat recovery device 2 adopts a plate heat exchanger structure, with several heat-conducting plates 23 inside. The heat-conducting plates 23 divide the inside of the device into mutually isolated waste gas layer and fresh air layer. The material of the heat-conducting plates 23 is 316L stainless steel or ND steel.

[0022] In this embodiment, the gas-to-gas waste heat recovery device 2 achieves efficient heat recovery and isolation through a plate heat exchanger structure. Its working principle involves using several parallel heat-conducting plates internally to completely physically isolate the high-temperature exhaust gas from the outside fresh air. The 150℃-200℃ high-temperature exhaust gas from the stenter flows through the exhaust gas layer, releasing heat, while the outside cold air absorbs heat as it flows through the fresh air layer. The high heat transfer coefficient of the heat-conducting plates preheats the fresh air to 120℃-170℃, after which it is returned to the stenter oven by a heat compensation fan to maintain thermal balance. Simultaneously, the exhaust gas temperature is reduced to 120℃-150℃ for subsequent purification. The beneficial effects of this device are mainly reflected in its extremely high durability and energy efficiency. The use of 316L stainless steel or ND steel effectively resists waste gas emissions. It is resistant to corrosive chemicals such as printing dyes, auxiliaries, and greases in the air, and has a long service life. Its structural design features a large heat exchange area, long flow path, low heat transfer resistance, and low air resistance, enabling it to transfer a large amount of heat energy under a small temperature difference, thereby significantly reducing the fuel consumption of the stenter and improving the high-temperature environment of the workshop. In other possible embodiments, the device can be upgraded to a high-efficiency superconducting waste heat recovery device, that is, combining heat pipe technology inside the heat-conducting plate, and further improving the heat exchange efficiency by utilizing the superconducting heat transfer performance of the heat plate and heat pipe. In addition, the device structure can adopt an overall elastic design to overcome the thermal stress generated by high-temperature thermal expansion, and is designed as an easy-to-clean modular structure to prevent dust accumulation and clogging, and together with a temperature control monitoring system, it can achieve safe, stable and continuous operation.

[0023] Furthermore, as a preferred embodiment of this solution and not a limitation, the air inlet 221 of the fresh air duct 22 is connected to the outside air, and the air outlet 222 of the fresh air duct 22 is connected to a heat compensation fan 223. The heat compensation fan 223 discharges the preheated fresh air into the shaping machine oven to maintain heat balance.

[0024] In this embodiment, a thermal compensation fan 223 is used as a power source to introduce ambient temperature fresh air into the fresh air flow channel 22 of the air-to-air waste heat recovery device. Utilizing the efficient heat transfer performance of the internal hot plate and heat pipes, the fresh air undergoes non-contact counter-current or cross-current heat exchange with the 150℃-200℃ high-temperature waste air flowing in the adjacent waste air flow channel 21. This rapidly raises the fresh air temperature from ambient temperature to 120℃-170℃, with the specific temperature depending on the wind speed and volume. The preheated high-temperature fresh air is then forcibly discharged into the setting machine oven for recirculation. This process directly recovers the sensible heat from the waste air, significantly reducing the energy consumption required by the setting machine to heat ambient temperature air. The amount of natural gas or steam is expected to reduce energy consumption by 20%-30%, thereby achieving significant energy saving, emission reduction, cost reduction and efficiency improvement while maintaining the thermal balance of the shaping machine oven. In other possible embodiments, the thermal compensation fan 223 can be configured with a frequency converter and connected to an intelligent control system. The fan speed and air supply volume can be automatically adjusted according to the real-time temperature or exhaust pressure of the shaping machine oven to achieve intelligent closed-loop control, avoiding excessive air supply leading to oven temperature fluctuations or insufficient air supply affecting drying efficiency. The fan position can be flexibly arranged at the front end of the air inlet 221 (blowing mode) or the rear end of the air outlet 222 (induced draft mode) to adapt to different pipeline layouts.

[0025] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the gas-water heat exchanger 3 includes a spray zone 31 and a dehydration zone 32. The spray zone 31 is provided with several sets of high-pressure nozzles 311 for spraying atomized water vapor to contact with the exhaust gas. The dehydration zone 32 is located behind the spray zone 31 and is provided with a mechanical demister or a wire mesh demister inside to remove fine water droplets carried in the exhaust gas, thereby reducing the temperature of the exhaust gas entering the electrostatic purification device 4 to 60℃-80℃.

[0026] In this embodiment, the gas-water heat exchanger 3, through the synergistic effect of its internal high-pressure spray system and dehydration structure, achieves deep cooling and pretreatment of the waste gas from the stenter. Its beneficial effect lies in rapidly cooling the waste gas, which still has a high temperature of approximately 120℃-150℃ after gas-to-gas waste heat recovery, to the optimal operating temperature range of 60℃-80℃ for the electrostatic purification device. This prevents damage to the honeycomb electrodes of the electrostatic module or the creation of a fire hazard due to high temperatures. Simultaneously, water washing removes approximately 70% of particulate matter and volatiles, reducing the processing load on the subsequent electrostatic field. Its working principle utilizes high-pressure circulating water within the spray zone 31, atomized through nozzles to form a high-density... Water mist comes into close contact with fibers and oil mist in the exhaust gas, causing them to condense and settle. The gas then enters the dehydration zone 32, where mechanical demisters or centrifugal force intercept fine water droplets, preventing water vapor from being carried into the high-voltage electric field and causing short circuits or creepage. In other possible embodiments, the main body of the device can be made of corrosion-resistant 2mm thick 201 or 304 stainless steel plate. Structurally, it can be designed as a horizontal or vertical layout. The dehydration zone can adopt a stainless steel slow-flow dehydration design to remove large oil particles and water droplets. The bottom of the device is usually connected to an oil-water separation device. The hot water after spraying is separated and recycled, realizing the dual functions of gas-water heat exchange and pollutant interception.

[0027] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the electrostatic purification device 4 includes a high-voltage electrostatic module 41 and an oil receiving tray 42. The high-voltage electrostatic module 41 adsorbs oil in the flue gas and causes it to condense when energized, and the condensed oil flows into the oil receiving tray 42.

[0028] In this embodiment, the electrostatic purification device 4 achieves efficient removal and resource recovery of tiny oil mist particles, aerosols, and VOCs in the waste gas of the stenter through the physical adsorption effect of a high-voltage electrostatic field. Its working principle is based on the cathode emitting high-density electrons (up to 100 million / cm³) and generating negative ions in a high-voltage electric field. This causes the oil mist and droplets with a particle size of less than 1 micrometer flowing through the electric field to become instantaneously charged. Driven by the electric field force (Coulomb force), the charged particles are adsorbed onto the anode plate (or anode tube), releasing their charge and condensing into neutral oil droplets. These droplets then flow naturally along the electrode plates under gravity to the oil collection tray 42 at the bottom for collection. This device has significant beneficial effects and extremely high purification efficiency (oil mist and VOCs removal rate can reach 90%). (above), and compared with mechanical filtration, it has the characteristics of low energy consumption and low wind resistance, and can effectively recover economically valuable waste oil; in other possible embodiments, the high-voltage electrostatic module 41 can be designed as a plate structure or a honeycomb conductive stainless steel anode tube bundle structure, and adopts a special power supply design of "secondary output high voltage and low current" to ensure the best adsorption effect with the strongest electric field filtration density and the lowest operating voltage and avoid arc discharge, thus eliminating fire hazards; in addition, in order to prevent the accumulation of oil and fiber on the electrode plates, the device is usually used in conjunction with an automatic spray cleaning system, which automatically sprays steam or hot water to clean the electrodes at regular intervals. The oily wastewater generated during cleaning is also collected in the oil receiving tray 42 and discharged to the subsequent oil-water separation and circulation device for treatment.

[0029] Furthermore, as a preferred embodiment of this solution and not a limitation, the electrostatic purification device 4 is equipped with an automatic spray cleaning device 43, which sprays and cleans the high-voltage electrostatic module 41 at regular intervals according to a preset program.

[0030] In this embodiment, the automatic spray cleaning device 43 is a key component ensuring the long-term stable operation and safety of the electrostatic purification system. Its working principle relies on a fully computerized intelligent control system, which automatically activates the cleaning water pump and valves according to a set time cycle. Hot water or steam is sprayed at high pressure through a spray network arranged above the electrostatic field onto the anode plate (or anode tube) and cathode line of the high-voltage electrostatic module 41. The physical scouring force peels off and washes away the sticky oil, fibrous dust, and particulate matter adsorbed and accumulated in the electric field into the oil collection tray 42 at the bottom, which is then discharged into an oil-water separator for further processing. Its significant advantage lies in completely solving the problems of increased resistance, decreased purification efficiency, and easy sluggishness caused by oil accumulation on the electrode plates in traditional electrostatic purification equipment. The technical pain point of arc discharge and even fire is addressed by achieving "minimal maintenance" or manual cleaning of the equipment, ensuring that the electrostatic field is always in good discharge and adsorption conditions, and guaranteeing the long-term stability of the removal rate of oil fumes and VOCs (e.g., ≥90%). In other possible embodiments, the device can be designed as a "steam + water" combined cleaning mode to enhance the dissolution ability of stubborn oil wax. At the same time, the device is also deeply integrated with the system's safety protection logic. When the exhaust temperature is detected to be too high or a fire hazard is detected, the control system will automatically cut off the high-voltage power supply and force the spray device to start emergency fire extinguishing and cooling. In addition, the cleaning water can be directly taken from the circulating clean water treated by the oil-water separator to achieve closed-loop utilization of water resources.

[0031] Furthermore, as a preferred embodiment of this solution and not a limitation, the wastewater and oil generated by the gas-water heat exchanger 3 and the electrostatic purification device 4 are fed into the oil-water separation device 6 for separation. The separated clean water is treated and then sent back to the automatic spray cleaning device 43 and / or the gas-water heat exchanger 3 for recycling.

[0032] In this embodiment, by constructing a closed-loop water treatment system of wastewater-separation-reuse, zero or minimal discharge of industrial water is achieved. Its significant benefits lie in greatly reducing fresh water consumption and wastewater treatment costs, creating economic benefits through waste oil recovery, and avoiding secondary pollution caused by wastewater discharge. Its working principle is as follows: the hot wastewater generated by the air-water heat exchanger 3 during spray cooling, which adsorbs oil mist and particulate matter, and the oily wastewater generated by the electrostatic purification device 4 during automatic cleaning, are both channeled into the oil-water separation device 6. Based on the shallow sedimentation theory and the principle of countercurrent flow separation, this device employs a composite process combining gravity, biochemical methods, and mechanical gaps to reduce the flow velocity of the incoming wastewater and transform it from turbulent to laminar flow. Utilizing density differences, oil floats while solid impurities settle. The floating waste oil and wax are then separated by a built-in self-cleaning mechanism. The oil-scraping system and oil-collecting water-separating device efficiently separate and collect the oil, which can be recycled and sold. The separated intermediate layer of clean water is filtered and buffered by multi-stage buffer tanks, and then pressurized by a dedicated circulating water pump or cleaning water pump, such as a 3kW water pump, and sent back to the air-water heat exchanger 3 for spray cooling or sent back to the automatic spray cleaning device 43 for plate rinsing, thus achieving recycling. Other possible embodiments include: to ensure optimal oil-water separation efficiency, the device is designed with a heat dissipation function to control the return water temperature below 60℃; to cope with the liquid level impact caused by the spray water falling back when the equipment is turned on and off, multiple buffer tanks are specially designed inside the device; the material can be made of corrosion-resistant SUS201 or 304 stainless steel, and equipped with an intelligent liquid level sensor and frequency conversion control system to prevent the water pump from running dry or the water tank from overflowing, ensuring that the system operates fully automatically and unattended.

[0033] The working principle of this embodiment is as follows: It is mainly divided into five stages: pre-treatment, waste heat recovery, cooling washing, electrostatic purification, and circulating self-cleaning. 1. Pre-processing ultrasonic cleaning and filtration: The high-temperature exhaust gas (approximately 150°C-200°C) from the stenter contains a large amount of grease, dust, and fibers. The exhaust gas first enters the ultrasonic cleaning and filtration device, where the cavitation effect of ultrasound generates a powerful micro-jet that effectively strips and intercepts large particles of dust and sticky oil and wax entrained in the exhaust gas. This step prevents subsequent heat exchanger fouling and blockage, ensuring long-term stable system operation.

[0034] 2. High-efficiency superconducting "gas-to-gas" waste heat recovery stage: The filtered clean high-temperature waste gas enters the waste gas channel of the high-efficiency superconducting waste heat recovery device. The device utilizes the superconducting heat transfer properties of the hot plate and / or heat pipe to conduct non-contact heat exchange between the waste gas and the ambient temperature fresh air introduced from the outside.

[0035] On the exhaust gas side: High-temperature exhaust gas releases heat, and the temperature decreases (usually to 120°C-150°C).

[0036] On the fresh air side: Outside fresh air absorbs heat and is preheated (up to 120°C-170°C), then is forcibly returned to the setting machine oven by a heat compensation fan for reuse. This process directly recovers sensible heat, significantly reducing the natural gas or steam energy consumption required for heating the setting machine.

[0037] 3. Gas-Water Heat Exchange and Cooling / Scrubbing Stage: Although the temperature of the exhaust gas decreases after heat recovery, its electrostatic adsorption capacity remains high, and it contains residual fine particles. The exhaust gas then enters the gas-water heat exchanger. Here, high-pressure circulating water mist comes into direct contact with the exhaust gas. Cooling: Rapidly reduce the temperature of the exhaust gas to 60°C-80°C (the optimal operating temperature range of the electrostatic module) to eliminate fire hazards.

[0038] Washing: Water mist condenses oil mist and particulate matter in the exhaust gas (removal rate of about 70%).

[0039] Dehydration: Fine water droplets carried in the exhaust gas are removed by mechanical demister plates or wire mesh to prevent water vapor from entering the electric field.

[0040] 4. High-voltage electrostatic adsorption purification stage: The cooled and dehydrated waste gas enters the electrostatic purification device. Under the action of a high-voltage DC power supply, a strong electric field is generated inside the electrostatic module (electrons are emitted from the cathode), causing the flowing oil fume particles and VOCs aerosols to become instantly charged. The charged particles move towards the anode plate (or anode tube) under the action of the electric field force (Coulomb force) and are adsorbed, subsequently condensing into oil droplets. The condensed oil flows down the electrode plate into a dedicated oil collection tray at the bottom. The purified, compliant gas is then extracted and discharged by an exhaust fan.

[0041] 5. Automatic Cleaning and Oil-Water Circulation Separation Stage: To prevent scale buildup on the static electrode plates and subsequent efficiency reduction, the system is equipped with an automatic spray cleaning system that periodically sprays hot water or steam to clean the electrodes according to a preset program. The oily wastewater generated during cleaning, as well as the spray wastewater from the gas-water heat exchanger, flows into the oil-water separator. This separator utilizes gravity sedimentation, mechanical gaps, and countercurrent flow principles to separate the oil and water into layers.

[0042] Waste oil: The floating oil and wax are automatically scraped off, recycled, and sold.

[0043] Clean water: The clean water in the lower layer is filtered and then pumped back to the system by a circulating water pump for spray cooling or equipment cleaning, realizing the closed-loop recycling of water resources.

[0044] The above are implementation methods provided in conjunction with specific content, and it is not intended that the specific implementation of this application is limited to these descriptions. Any methods or structures that are similar to those of this application, or any technical deductions or substitutions made based on the concept of this application, should be considered within the scope of protection of this application.

Claims

1. An integrated device for waste heat recovery and purification of waste gas from a stenter, characterized in that, include: The filter device (1), gas-to-gas waste heat recovery device (2), gas-to-water heat exchanger (3), electrostatic purification device (4) and exhaust fan (5) are connected in sequence along the direction of exhaust gas flow. The gas-to-gas waste heat recovery device (2) includes a waste gas flow channel (21) and a fresh air flow channel (22). The high-temperature waste gas discharged from the stenter flows in the waste gas flow channel (21), and the fresh air from the outside flows in the fresh air flow channel (22). The two exchange heat through the heat exchange wall, and the preheated fresh air after heat exchange is sent back to the stenter oven. The gas-water heat exchanger (3) is located between the gas-gas waste heat recovery device (2) and the electrostatic purification device (4) for further filtration and cooling of the cooled waste gas. The electrostatic purification device (4) is used to adsorb oil fumes and fine particles in the exhaust gas.

2. The integrated waste heat recovery and purification device for stenter exhaust gas according to claim 1, characterized in that, It also includes an oil-water separation device (6), which is connected to the drain outlets of the gas-water heat exchanger (3) and the electrostatic purification device (4) respectively, for collecting waste oil and separating clean water for recycling.

3. The integrated waste heat recovery and purification device for stenter exhaust gas according to claim 1, characterized in that, The filter device (1) is located at the exhaust gas inlet and is a mechanical bar filter or an ultrasonic cleaning filter, used to intercept large particles of dust and fibers in the exhaust gas.

4. The integrated device for waste heat recovery and purification of waste gas from a stenter as described in claim 1, characterized in that, The gas-to-gas waste heat recovery device (2) adopts a plate heat exchanger structure and has several heat-conducting plates (23) inside. The heat-conducting plates (23) divide the inside of the device into an isolated waste gas layer and a fresh air layer.

5. The integrated waste heat recovery and purification device for stenter exhaust gas according to claim 1, characterized in that, The air inlet (221) of the fresh air duct (22) is connected to the outside air, and the air outlet (222) of the fresh air duct (22) is connected to a heat compensation fan (223). The heat compensation fan (223) discharges the preheated fresh air into the shaping machine oven to maintain heat balance.

6. The integrated waste heat recovery and purification device for stenter exhaust gas according to claim 1, characterized in that, The gas-water heat exchanger (3) includes a spray zone (31) and a dehydration zone (32). The spray zone (31) is provided with several sets of high-pressure nozzles (311) for spraying atomized water vapor to contact with the exhaust gas. The dehydration zone (32) is located behind the spray zone (31) and is provided with a mechanical demister or a wire mesh demister to remove fine water droplets carried in the exhaust gas.

7. The integrated waste heat recovery and purification device for stenter exhaust gas according to claim 2, characterized in that, The electrostatic purification device (4) includes a high-voltage electrostatic module (41) and an oil receiving tray (42). The high-voltage electrostatic module (41) adsorbs oil in the flue gas and causes it to condense when energized. The condensed oil flows into the oil receiving tray (42).

8. The integrated waste heat recovery and purification device for stenter exhaust gas according to claim 7, characterized in that, The electrostatic purification device (4) is equipped with an automatic spray cleaning device (43), which sprays and cleans the high-voltage electrostatic module (41) according to a preset program at regular intervals.

9. The integrated waste heat recovery and purification device for stenter exhaust gas according to claim 8, characterized in that, The wastewater and oil generated by the gas-water heat exchanger (3) and the electrostatic purification device (4) are fed into the oil-water separator (6) for separation. The separated clean water is treated and then sent back to the automatic spray cleaning device (43) and / or the gas-water heat exchanger (3) for recycling.

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