Exhaust gas electric heating combustion treatment device for lost foam casting

Abstract

The application discloses a kind of lost foam casting tail gas electric heating combustion processing device, air inlet pipeline, with the tail gas discharge port of lost foam casting production line is sealed connection by flange, for the treatment gas generated in casting process is transported to pretreatment module;While pipeline inner wall is equipped with anticorrosive coating and guide vane;Pretreatment module is connected with the outlet end of air inlet pipeline and the air inlet end of direct combustion module, for dust removal to treatment gas;Heat recovery module and the outlet end of direct combustion module and the air inlet end of deep treatment module are detachably connected by flange, for recovering high-temperature tail gas waste heat discharged by direct combustion module and realizing energy recycling.The application has the beneficial effects of ensuring gas emission, reducing heat exchange efficiency decay, reducing maintenance energy consumption, reducing dust deposition and pressure loss, prolonging equipment service life, low manufacturing cost, not easy to damage and simple maintenance operation.

Description

Technical Field

[0001] This invention relates to a processing device, and more particularly to an electric heating combustion processing device for lost foam casting tail gas. Background Technology

[0002] During the production process of lost foam casting, exhaust gases containing a large amount of dust, volatile organic compounds, and combustible gases are continuously generated. If these exhaust gases are discharged directly without effective treatment, they will not only cause air pollution and damage the ecological environment, but also pose safety hazards due to the accumulation of combustible gases. At the same time, volatile organic compounds can harm the human respiratory and nervous systems. Therefore, it is necessary to purify them through scientific treatment methods. Electric heating combustion treatment can decompose harmful substances through high-temperature oxidation and is compatible with existing electric treatment equipment, making it the preferred technology for the treatment of such exhaust gases. In existing technologies, the treatment process for lost foam casting exhaust gas is relatively simple and lacks a systematic design. Typically, basic equipment such as filters and simple settling chambers are used for dust removal, removing some large dust particles through physical interception or gravity settling, but this is insufficient for handling fine dust. The pre-treated exhaust gas is then introduced into a conventional combustion device, where fuel combustion generates a high-temperature environment to attempt to oxidize and decompose volatile organic compounds and combustible gases. However, combustion temperature control is unstable, and the exhaust gas residence time in the combustion chamber is short. Some technologies add a single adsorption layer (such as ordinary activated carbon) before or after combustion for auxiliary purification, but the adsorption material lacks regeneration capabilities and must be replaced immediately after saturation. Finally, the treated gas is directly discharged through pipelines without a comprehensive exhaust gas detection and waste heat recovery system. The overall process only achieves basic pollutant reduction. The existing treatment technologies suffer from several drawbacks. First, the purification effect is insufficient. The combination of single dust removal and simple combustion is insufficient to completely remove fine dust and low-concentration residual volatile organic compounds (VOCs), often resulting in excessive concentrations of VOCs and particulate matter in the exhaust gas. Second, there is significant energy waste, with high-temperature exhaust gas (800-1000℃) being directly emitted after combustion, leaving a large amount of waste heat unutilized. Third, the equipment suffers from poor stability and maintainability. The heat exchange efficiency of the inner wall of the heat exchange equipment is prone to rapid decline due to the adhesion of residual particulate matter, requiring frequent replacement of adsorption materials and incurring high maintenance costs. Furthermore, the combustion system lacks flame arrestor, backfire prevention, and emergency shut-off mechanisms, posing risks of flame backflow and deflagration. Fourth, the level of automation is low, requiring manual monitoring of exhaust gas composition, adjustment of combustion parameters, and replacement of consumables. It cannot automatically adapt to actual operating conditions, making operation cumbersome and prone to human error.

[0003] Therefore, those skilled in the art are dedicated to providing an electric heating combustion treatment device for lost foam casting tail gas that can effectively solve the above-mentioned technical problems. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides an electric heating combustion treatment device for lost foam casting exhaust gas, comprising an intake pipe, a pretreatment module, a direct combustion module, a heat recovery module, a deep treatment module, and an exhaust pipe; The air intake pipe is connected to the exhaust port of the lost foam casting production line via a flange seal, and is used to transport the processing gas generated during the casting process to the pretreatment module; at the same time, the inner wall of the pipe is equipped with an anti-corrosion coating and a baffle plate to reduce dust deposition and pressure loss during the exhaust gas transportation process.

[0005] The pretreatment module is detachably connected to the outlet end of the air inlet pipe and the air inlet end of the direct combustion module via flanges, and is used to remove dust from the treated gas. The direct combustion module is connected to the outlet of the pretreatment module and the inlet of the heat recovery module via a flange seal. It is used to introduce the pretreated gas into a high-temperature combustion environment. The combustible gas and high-concentration volatile organic compounds are completely oxidized and decomposed through electric heating. The module integrates a combustion chamber, an electric heating component, and multiple safety protection components. The electric heating component continuously maintains a high temperature to ensure the immediate oxidation and decomposition of the exhaust gas. The combustion temperature is stably controlled at 850-1100℃, and the exhaust gas residence time is not less than 2 seconds. At the same time, the risk of overheating is prevented through a temperature abnormality detector and an emergency power-off switch.

[0006] The heat recovery module, detachably connected to the outlet of the direct-fired module and the inlet of the deep treatment module via flanges, is used to recover the waste heat from the high-temperature exhaust gas discharged from the direct-fired module and achieve energy recycling. Its core is a shell-and-tube heat exchanger. A self-cleaning coating, 50-80 μm thick and with a surface roughness Ra≤0.8 μm, is applied to the shell-and-tube heat exchanger of the heat recovery module. This reduces the adhesion of residual particulate matter in the high-temperature exhaust gas to the inner wall of the heat exchange tubes, lowers the rate of heat exchange efficiency decay, and extends the self-cleaning cycle to more than 6 months. The high-temperature medium channel of the heat exchanger receives 800-1000 liters of heat from the direct-fired module. The high-temperature gas at 00℃ has a dual-channel low-temperature medium channel. One channel connects to the inlet of the pretreatment module to preheat the exhaust gas, while the other connects to an external lost foam drying chamber to provide drying heat. Similarly, the heat recovery module's low-temperature medium channel also has a dual-channel design: one channel connects to the inlet of the pretreatment module to preheat the exhaust gas, and the other connects to an external lost foam drying chamber to provide drying heat. Through reverse heat exchange between the hot and cold media, the high-temperature gas temperature is reduced from 800-1000℃ to 300-400℃. The initial temperature of the low-temperature medium is room temperature, and after heating, its temperature reaches 175-275℃. The heat exchanger adopts a shell-and-tube structure. The inlet temperature of the high-temperature medium channel is 800-1000℃, and the outlet temperature drops to 300-400℃. The temperature rise of the low-temperature medium channel is 150-250℃.

[0007] The deep processing module is connected to the outlet end of the heat recovery module and the inlet end of the exhaust pipe through a flange seal, and is used to perform deep oxidation and purification of the low concentration of volatile organic compounds remaining after heat recovery. The exhaust duct, connected to the outlet of the deep treatment module and the external exhaust stack via flange seals, is used to stably discharge clean gas that has passed multi-stage purification treatment into the atmosphere. The duct is made of corrosion-resistant stainless steel with a smooth, burr-free inner wall to reduce airflow resistance. An external thermal insulation layer prevents condensation. A gas sampling port is pre-installed in the middle of the duct for regular monitoring of emission indicators. The thermal insulation layer of the exhaust duct is made of aluminum silicate fiber, 50-80mm thick, and is protected by an outer galvanized iron sheet. The sampling port is equipped with a sealing cap and a quick connector. Sampling is conducted monthly, and the monitored indicators include volatile organic compound (VOC) concentration, particulate matter concentration, sulfur dioxide concentration, nitrogen oxide (NOx) concentration, and oxygen content.

[0008] Furthermore, the pretreatment module includes a dust removal unit, a condensation hopper, and a five-segment transverse adsorption unit; The dust removal unit is equipped with a spray assembly, and its top is connected to a condensation hopper. The liquid outlet of the condenser is connected to the dust removal unit for reflux. The five-segment horizontal adsorption unit includes five horizontally arranged adsorption components, each of which is filled with activated carbon fiber adsorption material.

[0009] Furthermore, the dust removal unit includes a dust removal box and a dust collection water tank; The top of the dust collector is equipped with a buffer box, and the upper end of the buffer box is equipped with an air inlet pipe. The treated gas enters the buffer box through the air inlet pipe, is buffered, and then discharged into the dust collector. The interior of the dust collector is divided into a dust collection area and a dust discharge area by a partition plate. The lower half of the partition plate has a through opening. The dust removal area is equipped with a spray assembly located in the upper half of the partition plate. The dust collection tank is filled with liquid, which is not higher than the through opening. An air outlet pipe is provided at the upper end of the dust discharge area.

[0010] Furthermore, the spray assembly includes a dust collector cylinder, on which at least two positioning frames are fitted. Each positioning frame is detachably connected to the inner wall of the dust collector housing. An inner water ring is provided inside the dust collector cylinder, and a plurality of first spray heads are provided on the inner water ring. The outer wall of the inner water ring is connected to the inner wall of the outer water ring through a plurality of connecting rods. A plurality of second spray heads are provided at the upper end of the outer water ring. Each first spray head and each second spray head is arranged in a circular array around the center line of the inner water ring. The outlets of each first spray head and each second spray head face upward. The spray angle of the first spray head is 90°, the spray angle of the second spray head is 120°, and the spray particle size is 50-100μm. A flow sensor and a regulating valve are provided on the main water pipe. The spray flow rate is automatically adjusted according to the particulate matter concentration in the air inlet pipe, with an adjustment range of 10-30m³ / h. Both the inner water ring and the outer water ring are supported by a support frame provided on the inner wall of the dust collector cylinder. The dust collector is equipped with a main water pipe, the inlet of which is connected to the lower half of the circulation tank. The circulation tank is located on one side of the dust collector. The lower end of the dust collection tank is connected to the upper end of the circulation tank via a return water pipe. The liquid filtered by the filter assembly in the dust collection tank enters the circulation tank through the return water pipe. The upper end of the circulation tank is also equipped with a water replenishment connector. The front end of the circulation tank is equipped with a door. As a further preferred embodiment, the circulation tank is equipped with a liquid level sensor and an automatic water replenishment device. When the liquid level is lower than the set value, the automatic water replenishment device replenishes the liquid through the water replenishment connector to maintain a stable liquid level in the dust collection tank.

[0011] Furthermore, the support frame includes several positioning columns connected to the inner wall of the dust collector cylinder, and the inner side of each positioning column is simultaneously connected to a positioning ring. Both the inner water ring and the outer water ring are supported by the positioning ring.

[0012] Furthermore, the filter assembly is disposed inside the dust collection water tank and located above the return water pipe. The filter assembly includes a drawer-type filter layer box with a plurality of filter holes inside the drawer-type filter layer box and a handle is provided on the drawer-type filter layer box.

[0013] Furthermore, the five-segment transverse adsorption unit also includes an input pipe. The five adsorption components of the five-segment transverse adsorption unit adopt an alternating operation mode of four adsorption and one regeneration. The front end of the five-segment transverse adsorption unit of the pretreatment module is equipped with a volatile organic compound concentration grade detection sensor. The number of adsorption components is automatically switched according to the volatile organic compound concentration range. 2-3 adsorption components are activated at low concentration, 3-4 adsorption components are activated at medium concentration, and all adsorption components are activated at high concentration. The low concentration is ≤50mg / m³, the medium concentration is 50-200mg / m³, and the high concentration is >200mg / m³. The airflow switching is controlled by a solenoid valve group. The adsorption saturation time of a single adsorption component is ≥8h, and the regeneration time is ≤2h. The five-segment transverse adsorption unit also includes an online regeneration component for adsorbent materials, comprising a hot air backflushing pipeline and a nitrogen purging system. The hot air temperature is controlled at 120-150℃, the backflushing pressure is 0.3-0.5MPa, and the nitrogen purging flow rate is 5-8m³ / h. The regeneration mode is automatically switched according to the adsorption saturation of the adsorption component by a PLC controller. The regenerated adsorbent material can be reused, extending its service life by 3-5 times.

[0014] Furthermore, the combustion chamber of the direct-fired module is lined with refractory bricks, and the combustion temperature is controlled at 850-1100℃, with the exhaust gas residence time in the combustion chamber ≥2s; the electric heating component adopts a high-frequency induction heating or resistance heating structure, and is equipped with a power adjustment module. The heating power can be automatically adapted according to the concentration of volatile organic compounds and the exhaust gas flow rate, with an adjustment range of 50-200kW, to ensure that the combustion chamber temperature is stably maintained at 850-1100℃. It also includes a safety protection component, which includes a temperature anomaly detector and an emergency power-off switch. The temperature anomaly detector is electrically connected to the emergency power-off switch, and when a temperature anomaly is detected, the electric heating power supply is cut off immediately. Furthermore, it also includes a control system, which comprises a gas detection sensor, a temperature sensor, and a PLC controller. The gas detection sensor is installed in the intake and exhaust pipes to detect the concentrations of volatile organic compounds, combustible gases, and particulate matter. The temperature sensor is installed in the direct combustion module and the heat recovery module. The PLC controller automatically adjusts the spray flow rate, electric heating power, valve opening, and UV lamp power based on the detection data. The PLC controller is equipped with a touch screen operating interface, which can display the operating parameters of each module in real time and has parameter alarms, historical data storage, and a remote monitoring interface.

[0015] Furthermore, the anti-corrosion coating of the air intake pipe is made of polytetrafluoroethylene with a thickness of 1.5-2.0mm. The guide plate has an arc-shaped structure with an angle of 30-45° with the inner wall of the pipe. The spacing between adjacent guide plates is 1 / 3-1 / 2 of the pipe diameter. The surface of the guide plate is smooth to further reduce the dust deposition rate. The deep processing module adopts a UV photocatalytic oxidation and low-temperature plasma synergistic purification structure. The UV lamp uses a dual-band combination of 254nm and 185nm wavelengths. The plasma discharge power can be automatically adjusted according to the concentration of volatile organic compounds. Under the synergistic effect, the removal rate of low-concentration volatile organic compounds is increased to more than 95%.

[0016] The present invention has the following beneficial effects: 1. This invention employs a three-stage purification process: pretreatment, direct combustion, and deep treatment. The pretreatment module removes particulate matter and some volatile organic compounds (VOCs) through spray dust removal and activated carbon fiber adsorption. The direct combustion module decomposes high-concentration VOCs and combustible gases at a high temperature of 850-1100℃. The deep treatment module achieves a VOC removal rate of over 95% through the synergistic effect of dual-band UV photocatalysis and low-temperature plasma. The exhaust pipe is regularly tested for VOCs, particulate matter, sulfur dioxide, nitrogen oxides, and other indicators to ensure that the gas emissions meet standards. 2. The heat recovery module recovers waste heat from high-temperature exhaust gas at 800-1000℃ through a shell-and-tube heat exchanger. After the low-temperature medium is heated to 175-275℃, one path preheats the exhaust gas to be treated, and the other path provides heat energy to the lost foam drying oven, realizing energy cascade utilization. The nano-titanium dioxide self-cleaning coating on the inner wall of the heat exchanger extends the cleaning cycle to more than 6 months, reduces heat exchange efficiency decay, and reduces maintenance energy consumption. The direct-fired module is equipped with a temperature abnormality detector and an emergency power-off switch to monitor the temperature status in real time. In case of abnormality, the electric heating power supply is immediately cut off to eliminate the risk of overheating. 3. The intake pipe is coated with polytetrafluoroethylene for corrosion protection and has an arc-shaped baffle to reduce dust accumulation and pressure loss; the exhaust pipe is made of corrosion-resistant stainless steel and has an external heat insulation layer to prevent condensation and extend the service life of the equipment. 4. Equipped with a PLC control system, it collects data in real time through gas detection sensors and temperature sensors, and automatically adjusts parameters such as spray flow rate, electric heating power, and UV lamp power without frequent manual intervention. The pretreatment module adsorption component adopts a four-adsorption-one-regeneration alternating mode, with a regeneration time of ≤2 hours. The adsorption material can be reused, extending its service life by 3-5 times. The filter component has a drawer-type design with automatic liquid level replenishment. It also has the advantages of low manufacturing cost, not being easily damaged, and simple maintenance and operation. Attached Figure Description

[0017] Figure 1 This is a structural schematic diagram of a specific embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the connection structure of the dust removal unit, dust collection water tank, air inlet pipe and air outlet pipe in this invention; Figure 3This is a structural schematic diagram of the dust collection box, partition plate, dust collection area and dust discharge area in this invention; Figure 4 This is a schematic diagram of the drawer-type filter layer box in this invention; Figure 5 This is a cross-sectional view of the dust collector cylinder in this invention; Figure 6 This is a schematic diagram of the connection structure between the dust collector and the positioning frame in this invention; Figure 7 This is a schematic diagram of the spray assembly in this invention; Figure 8 This is a schematic diagram of the connection structure of the dust collector cylinder, positioning column and positioning ring in this invention; Figure 9 This is a schematic diagram of the connection structure of the dust collector, positioning ring, inner water ring, outer water ring and support frame in this invention; Figure 10 This is a schematic diagram showing the positional relationship between the air intake pipe, dust collector, positioning frame, and through opening in this invention. Figure 11 This is a schematic diagram of the dust collection water tank in this invention; Figure 12 This is a structural schematic diagram of the filter assembly, drawer-type filter layer box, filter holes, and handle in this invention; Figure 13 This is a cross-sectional structural diagram showing the connection between the main water pipe, the inner water ring, and the outer water ring in this invention. Figure 14 yes Figure 13 A magnified view of the structure at point A in the middle; Figure 15 This is a schematic diagram of the connection structure between the five-segment transverse adsorption unit and the input pipe in this invention.

[0019] The attached diagram lists the components represented by each number as follows: 1. Dust removal unit; 2. Five-segment horizontal adsorption unit; 3. Spray assembly; 6. Adsorption assembly; 10. Dust removal box; 11. Dust collection water tank; 12. Buffer box; 13. Air inlet pipe; 15. Divider plate; 16. Dust removal area; 17. Dust discharge area; 18. Through opening; 19. Air outlet pipe; 20. Dust collection cylinder; 21. Positioning frame; 22. Inner water ring; 23. First spray head; 26. Connecting rod; 27. Outer water ring; 28. Second spray head; 29. ​​Support frame; 30. Main water pipe; 31. Circulation box; 32. Return water pipe; 33. Filter assembly; 35. Box door; 36. Water replenishment connector; 37. Positioning column; 38. Positioning ring; 39. Drawer-type filter layer box; 50. Filter hole; 51. Handle; 52. Input pipe. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments: In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] like Figures 1 to 15 As shown, an electric heating combustion treatment device for lost foam casting exhaust gas is described. It includes an intake duct, a pretreatment module, a direct combustion module, a heat recovery module, a deep treatment module, and an exhaust duct; The intake pipe is connected to the exhaust port of the lost foam casting production line via a flange seal. It is used to transport the processing gas containing dust, volatile organic compounds and combustible gases generated during the casting process to the pretreatment module. At the same time, the inner wall of the pipe is equipped with an anti-corrosion coating and a baffle plate to reduce dust deposition and pressure loss during the exhaust gas transportation process.

[0023] The pretreatment module is detachably connected to the outlet end of the air inlet pipe and the air inlet end of the direct combustion module via flanges, and is used to remove dust, volatile organic compounds and combustible gases from the treated gas. The direct combustion module is connected to the outlet of the pretreatment module and the inlet of the heat recovery module via a flange seal. It is used to introduce the pretreated gas into a high-temperature combustion environment. The combustible gas and high-concentration volatile organic compounds are completely oxidized and decomposed through electric heating. The module integrates a combustion chamber, an electric heating component, and multiple safety protection components. The electric heating component continuously maintains a high temperature to ensure the immediate oxidation and decomposition of the exhaust gas. The combustion temperature is stably controlled at 850-1100℃, and the exhaust gas residence time is not less than 2 seconds. At the same time, the risk of overheating is prevented through a temperature abnormality detector and an emergency power-off switch.

[0024] The heat recovery module, detachably connected to the outlet of the direct-fired module and the inlet of the deep treatment module via flanges, is used to recover the waste heat from the high-temperature exhaust gas discharged from the direct-fired module and achieve energy recycling. Its core is a shell-and-tube heat exchanger. Within the shell-and-tube heat exchanger of the heat recovery module, a self-cleaning coating made of nano-titanium dioxide composite is applied. The coating thickness is 50-80μm, and the surface roughness Ra≤0.8μm, reducing the adhesion of residual particulate matter in the high-temperature exhaust gas to the inner wall of the heat exchange tubes, reducing the rate of heat exchange efficiency decay, and extending the self-cleaning cycle to more than 6 months. The high-temperature medium channel of the heat exchanger receives the waste heat from the 80°C exhaust gas after direct-fired combustion. The high-temperature gas (0-1000℃) has a dual-channel low-temperature medium channel. One channel connects to the inlet of the pretreatment module to preheat the exhaust gas, while the other connects to an external lost foam drying chamber to provide drying heat. Similarly, the heat recovery module's low-temperature medium channel also has a dual-channel design: one channel connects to the inlet of the pretreatment module to preheat the exhaust gas, and the other connects to the external lost foam drying chamber to provide drying heat. Through counter-current heat exchange between the hot and cold media, the high-temperature gas temperature drops from 800-1000℃ to 300-400℃. The initial temperature of the low-temperature medium is approximately 25℃ (room temperature), and after heating, the temperature reaches 175-275℃. The heat exchanger adopts a shell-and-tube structure. The inlet temperature of the high-temperature medium channel is 800-1000℃, and the outlet temperature drops to 300-400℃. The temperature rise of the low-temperature medium channel is 150-250℃.

[0025] The deep processing module is connected to the outlet end of the heat recovery module and the inlet end of the exhaust pipe through a flange seal, and is used to perform deep oxidation and purification of the low concentration of volatile organic compounds remaining after heat recovery. The exhaust duct, connected to the outlet of the deep treatment module and the external exhaust stack via flange seals, is used to stably discharge clean gas that has passed multi-stage purification treatment into the atmosphere. The duct is made of corrosion-resistant stainless steel with a smooth, burr-free inner wall to reduce airflow resistance. An external thermal insulation layer prevents condensation. A gas sampling port is pre-installed in the middle of the duct for regular monitoring of emission indicators. The thermal insulation layer of the exhaust duct is made of aluminum silicate fiber, 50-80mm thick, and is protected by an outer galvanized iron sheet. The sampling port is equipped with a sealing cap and a quick connector. Sampling is conducted monthly, and the monitored indicators include volatile organic compound (VOC) concentration, particulate matter concentration, sulfur dioxide concentration, nitrogen oxide (NOx) concentration, and oxygen content.

[0026] The pretreatment module includes a dust removal unit 1, a condensation hopper, and a five-segment horizontal adsorption unit 2; The dust removal unit 1 is equipped with a spray assembly 3, the top of which is connected to the condensation hopper; The liquid outlet of the condenser is connected to the dust removal unit 1 for reflux. The five-segment horizontal adsorption unit 2 includes five horizontally arranged adsorption components 6, each of which is filled with activated carbon fiber adsorption material.

[0027] The dust removal unit 1 includes a dust removal box 10 and a dust collection water tank 11; The top of the dust collection box 10 is provided with a buffer box 12, and the upper end of the buffer box 12 is provided with an air inlet pipe 13. The treated gas enters the buffer box 12 through the air inlet pipe 13 for buffering and then is discharged into the dust collection box 10. The interior of the dust collection box 10 is divided into a dust collection area 16 and a dust discharge area 17 by a partition plate 15. The lower half of the partition plate 15 has a through opening 18. The dust removal area 16 has a spray assembly 3, which is located in the upper half of the partition plate 15. The dust collection water tank 11 is filled with liquid, which is not higher than the through opening 18. The upper end of the dust discharge area 17 is provided with an air outlet pipe 19.

[0028] The spray assembly 3 includes a dust collector cylinder 20, on which at least two positioning frames 21 are fitted. Each positioning frame 21 is detachably connected to the inner wall of the dust collector housing 10. An inner water ring 22 is provided inside the dust collector cylinder 20, and a plurality of first spray heads 23 are provided on the inner water ring 22. The outer wall of the inner water ring 22 is connected to the inner wall of an outer water ring 27 through a plurality of connecting rods 26. A plurality of second spray heads 28 are provided at the upper end of the outer water ring 27. Each first spray head 23 and each second spray head 28 surrounds the inner water ring 20. The centerline of the 2 is arranged in a circular array. The outlets of each first spray head 23 and each second spray head 28 face upwards. The spray angle of the first spray head 23 is 90° and the spray angle of the second spray head 28 is 120°. The spray particle size is 50-100μm. The main water pipe 30 is equipped with a flow sensor and a regulating valve. The spray flow rate is automatically adjusted according to the particulate matter concentration in the air inlet pipe. The adjustment range is 10-30m³ / h. The inner water ring 22 and the outer water ring 27 are both supported by the support frame 29 set on the inner wall of the dust collector 20. The dust collection box 10 is equipped with a main water pipe 30, the inlet end of which is connected to the lower half of the circulation box 31. The circulation box 31 is located on one side of the dust collection box 10. The lower end of the dust collection water tank 11 is connected to the upper end of the circulation box 31 through a return water pipe 32. The liquid filtered by the filter assembly 33 in the dust collection water tank 11 enters the circulation box 31 through the return water pipe 32. The upper end of the circulation box 31 is also equipped with a water replenishment connector 36. The front end of the circulation box 31 is equipped with a door 35. As a further preferred embodiment, the circulation box is equipped with a liquid level sensor and an automatic water replenishment device. When the liquid level is lower than the set value and 10cm below the through opening, the automatic water replenishment device replenishes the liquid through the water replenishment connector to maintain a stable liquid level in the dust collection water tank.

[0029] The support frame 29 includes a plurality of positioning posts 37 connected to the inner wall of the dust collector 20. The inner side of each positioning post 37 is also connected to a positioning ring 38. The inner water ring 22 and the outer water ring 27 are both supported by the positioning ring 38.

[0030] The filter assembly 33 is disposed inside the dust collection water tank 11 and located above the return water pipe 32. The filter assembly 33 includes a drawer-type filter layer box 39, which has a plurality of filter holes 50 and a handle 51.

[0031] The five-segment transverse adsorption unit 2 also includes an input pipe 52. The five adsorption components of the five-segment transverse adsorption unit adopt a four-adsorption-one-regeneration alternating operation mode. The front end of the five-segment transverse adsorption unit of the pretreatment module is equipped with a volatile organic compound concentration grade detection sensor. The number of adsorption components is automatically switched according to the volatile organic compound concentration range. 2-3 adsorption components are activated at low concentration, 3-4 adsorption components are activated at medium concentration, and all adsorption components are activated at high concentration. The low concentration is ≤50mg / m³, the medium concentration is 50-200mg / m³, and the high concentration is >200mg / m³. The airflow switching is controlled by a solenoid valve group. The adsorption saturation time of a single adsorption component is ≥8h, and the regeneration time is ≤2h. The five-segment transverse adsorption unit 2 also includes an online regeneration component for adsorption materials, including a hot air backflushing pipeline and a nitrogen purging system. The hot air temperature is controlled at 120-150℃, the backflushing pressure is 0.3-0.5MPa, and the nitrogen purging flow rate is 5-8m³ / h. The regeneration mode is automatically switched according to the adsorption saturation of the adsorption component by a PLC controller. The regenerated adsorption material can be reused, extending its service life by 3-5 times.

[0032] The combustion chamber of the direct-fired module is lined with refractory bricks, and the combustion temperature is controlled at 850-1100℃. The residence time of the exhaust gas in the combustion chamber is ≥2s. The electric heating component adopts a high-frequency induction heating or resistance heating structure and is equipped with a power adjustment module. The heating power can be automatically adapted according to the concentration of volatile organic compounds and the exhaust gas flow rate, with an adjustment range of 50-200kW, to ensure that the combustion chamber temperature is stably maintained at 850-1100℃. It also includes a safety protection component, which includes a temperature anomaly detector and an emergency power-off switch. The temperature anomaly detector is electrically connected to the emergency power-off switch, and when a temperature anomaly is detected, the electric heating power supply is cut off immediately. The invention also includes a control system, which comprises a gas detection sensor, a temperature sensor, and a PLC controller. The gas detection sensor is installed in the intake and exhaust pipes to detect the concentrations of volatile organic compounds, combustible gases, and particulate matter. The temperature sensor is installed in the direct combustion module and the heat recovery module. The PLC controller automatically adjusts the spray flow rate, electric heating power, valve opening, and UV lamp power based on the detection data. The PLC controller is equipped with a touch screen interface that can display the operating parameters of each module in real time, such as temperature, pressure, gas concentration, and flow rate. It also features parameter alarms, historical data storage with a storage period of ≥1 year, and a remote monitoring interface supporting the Modbus-RTU protocol.

[0033] The anti-corrosion coating of the air intake pipe is made of polytetrafluoroethylene with a thickness of 1.5-2.0mm. The baffle is an arc-shaped structure with an angle of 30-45° with the inner wall of the pipe. The spacing between adjacent baffles is 1 / 3-1 / 2 of the pipe diameter. The surface of the baffle is smooth to further reduce the dust deposition rate. The deep processing module adopts a UV photocatalytic oxidation and low-temperature plasma synergistic purification structure. The UV lamp uses a dual-band combination of 254nm and 185nm wavelengths. The plasma discharge power can be automatically adjusted within the range of 500-1500W according to the concentration of volatile organic compounds. Under the synergistic effect, the removal rate of low-concentration volatile organic compounds is increased to over 95%.

[0034] The optimal working principle of this invention is as follows: In the exhaust gas introduction stage, the inner wall of the intake pipe, coated with PTFE (polytetrafluoroethylene) for corrosion protection, and the arc-shaped guide plate are sealed to the exhaust port of the casting production line via flanges, conveying dust, volatile organic compounds, and combustible gases to the pretreatment module. The guide plate forms an angle of 30-45° with the inner wall of the pipe, and the adjacent spacing is 1 / 3 1 / 2 of the pipe diameter to reduce dust deposition and pressure loss. The working gas of the dust removal unit 1 enters the buffer box 12 through the intake pipe 13 and is then discharged into the dust removal area 16 of the dust removal box 10. The main water pipe 30 transports the liquid in the circulation box 31 to the inner water ring 22 and the outer water ring 27. The first spray head 23 (90° spray angle) and the second spray head 28 (120° spray angle) spray droplets with a particle size of 50-100μm to capture particulate matter in the gas. The dust-laden liquid falls into the dust collection water tank 11 and passes through a drawer-type filter layer. After filtration through the filter holes 50 of the housing 39, the gas flows back to the circulation housing 31 for recycling via the return water pipe 32. When the liquid level is lower than the set value, the automatic water replenishment device replenishes water through the water replenishment connector 36. The purified gas enters the dust discharge area 17 through the through opening 18 of the partition plate 15 and is discharged through the gas outlet pipe 19. The working gas of the five-stage horizontal adsorption unit 2 enters the five horizontally arranged adsorption components 6, and the internal activated carbon fiber adsorption material adsorbs part of the volatile organic compounds. Controlled by the solenoid valve group, the five adsorption components adopt a four-adsorption-one-regeneration alternating mode, with an adsorption saturation time > 8h and a regeneration time ≤ 2h.During regeneration, the hot air backflushing pipeline at 120-150℃ and 0.3-0.5MPa works in conjunction with the nitrogen purging system at a flow rate of 58m³ / h. The PLC controller automatically switches the regeneration mode according to the adsorption saturation. The pretreated gas enters the direct combustion module, where the combustion chamber is lined with refractory bricks. The electric heating components are activated and maintain a high temperature environment of 850-1100℃. The gas stays in the combustion chamber for ≥2 seconds, ensuring complete oxidation and decomposition of combustible gases and high-concentration volatile organic compounds. When the temperature anomaly detector detects an abnormal temperature, the emergency power-off switch immediately cuts off the electric heating power supply to prevent overheating. The high-temperature combustion exhaust gas at 800-1000℃ enters the core of the shell-and-tube heat exchanger heat recovery module. The nano-titanium dioxide composite self-cleaning coating on the inner wall of the heat exchanger reduces particulate matter adhesion. The low-temperature medium at approximately 25℃ is divided into two counter-current heat exchange paths: one path preheats the exhaust gas to be treated in the pretreatment module, and the other path provides heat energy to the external lost foam drying chamber. The high-temperature exhaust gas temperature drops to 300-400℃, and the low-temperature medium... The gas is heated to 175-275℃ to achieve waste heat recovery and recycling; the gas enters the deep treatment module, where UV photocatalytic oxidation with 254nm and 185nm dual-band UV lamps and low-temperature plasma works synergistically. The plasma discharge power is automatically adjusted from 500-1500W according to the concentration of volatile organic compounds, removing more than 95% of low-concentration residual volatile organic compounds; the qualified gas is discharged through a corrosion-resistant stainless steel exhaust pipe with a 50-80mm aluminum silicate fiber insulation layer on the outside of the pipe and an outer galvanized iron sheet protection layer to prevent condensation; gas detection sensors in the intake / exhaust pipes detect the concentration of volatile organic compounds, combustible gases, and particulate matter; temperature sensors in the direct combustion / heat recovery module monitor the temperature; the PLC controller displays parameters through a touch screen interface, automatically adjusts the spray flow rate, electric heating power, etc., supports historical data storage of ≥1 year and remote monitoring via Modbus-RTU protocol; emission indicators are detected monthly through a sampling port with a sealed cap and quick connector in the middle section of the exhaust pipe.

[0035] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A device for electrically heated combustion treatment of lost foam casting tail gas, characterized in that: It includes an intake duct, a pretreatment module, a direct combustion module, a heat recovery module, a deep treatment module, and an exhaust duct; The air intake pipe is connected to the exhaust port of the lost foam casting production line via a flange seal, and is used to transport the processing gas generated during the casting process to the pretreatment module; at the same time, the inner wall of the pipe is equipped with an anti-corrosion coating and a baffle plate. The pretreatment module is connected to the outlet end of the air inlet pipe and the air inlet end of the direct combustion module, and is used to remove dust from the treated gas. The direct combustion module is connected to the outlet of the pretreatment module and the inlet of the heat recovery module, and is used to introduce the pretreated gas into the high-temperature combustion environment. The heat recovery module is detachably connected to the outlet end of the direct combustion module and the inlet end of the deep treatment module via flanges. It is used to recover the waste heat of the high-temperature exhaust gas discharged from the direct combustion module and realize energy recycling. The deep processing module is connected to the outlet end of the heat recovery module and the inlet end of the exhaust pipe, and is used to perform deep oxidation and purification on the low concentration of VOCs remaining after heat recovery. The exhaust pipe is connected to the outlet end of the deep treatment module and the external exhaust stack, and is used to stably discharge the clean gas that has passed the multi-stage purification treatment into the atmosphere.

2. The electric heating combustion treatment device for lost foam casting tail gas according to claim 1, characterized in that: The pretreatment module includes a dust removal unit (1), a condensation hopper, and a five-segment horizontal adsorption unit (2). The dust removal unit (1) is equipped with a spray assembly (3), and its top is connected to the condensation hopper; The liquid outlet of the condenser is connected to the dust removal unit (1) via a return flow. The five-segment horizontal adsorption unit (2) includes five horizontally arranged adsorption components (6), and each adsorption component (6) is filled with activated carbon fiber adsorption material.

3. The electric heating combustion treatment device for lost foam casting tail gas according to claim 2, characterized in that: The dust removal unit (1) includes a dust removal box (10) and a dust collection water tank (11); The top of the dust collector (10) is provided with a buffer box (12), and the upper end of the buffer box (12) is provided with an air inlet pipe (13). The treated gas enters the buffer box (12) through the air inlet pipe (13) for buffering and then is discharged into the dust collector (10). The dust collector (10) is divided into a dust collection area (16) and a dust discharge area (17) by a partition plate (15). The lower half of the partition plate (15) has a through opening (18). The dust removal area (16) has a spray assembly (3), which is located in the upper half of the partition plate (15). The dust collection water tank (11) is filled with liquid, which is not higher than the through opening (18). The upper end of the dust discharge area (17) is provided with an air outlet pipe (19).

4. The electric heating combustion treatment device for lost foam casting tail gas according to claim 3, characterized in that: The spray assembly (3) includes a dust collector cylinder (20), on which at least two positioning frames (21) are fitted. Each positioning frame (21) is detachably connected to the inner wall of the dust collector housing (10). An inner water ring (22) is provided inside the dust collector cylinder (20), and a plurality of first spray heads (23) are provided on the inner water ring (22). The outer wall of the inner water ring (22) is connected to the inner wall of the outer water ring (27) through a plurality of connecting rods (26). A plurality of second spray heads (28) are provided at the upper end of the outer water ring (27). Each first spray head (23) and each second spray head (28) The inner water ring (22) is arranged in a circular array around the center line of the inner water ring (22). The outlets of each first spray head (23) and each second spray head (28) face upwards. The spray angle of the first spray head (23) is 90° and the spray angle of the second spray head (28) is 120°. The spray particle size is 50-100μm. A flow sensor and regulating valve are provided on the main water pipe (30). The spray flow rate is automatically adjusted according to the particle concentration in the air inlet pipe. The adjustment range is 10-30m³ / h. The inner water ring (22) and the outer water ring (27) are both supported by a support frame (29) set on the inner wall of the dust collector (20). The dust collector (10) is provided with a main water pipe (30). The water inlet of the main water pipe (30) is connected to the lower half of the circulation box (31). The circulation box (31) is located on one side of the dust collector (10). The lower end of the dust collection water tank (11) is connected to the upper end of the circulation box (31) through the return water pipe (32). The liquid filtered by the filter assembly (33) in the dust collection water tank (11) enters the circulation box (31) through the return water pipe (32). The upper end of the circulation box (31) is also provided with a water replenishment connector (36). The front end of the circulation box (31) is provided with a door (35).

5. The electric heating combustion treatment device for lost foam casting tail gas according to claim 4, characterized in that: The support frame (29) includes several positioning columns (37) connected to the inner wall of the dust collector (20). The inner side of each positioning column (37) is connected to a positioning ring (38). The inner water ring (22) and the outer water ring (27) are both supported by the positioning ring (38).

6. The electric heating combustion treatment device for lost foam casting tail gas according to claim 5, characterized in that: The filter assembly (33) is located inside the dust collection water tank (11) and above the return water pipe (32). The filter assembly (33) includes a drawer-type filter layer box (39), which has several filter holes (50) and a handle (51) on it.

7. The electric heating combustion treatment device for lost foam casting tail gas according to claim 6, characterized in that: The five-segment transverse adsorption unit (2) also includes an input pipe (52). The five adsorption components of the five-segment transverse adsorption unit adopt a four-adsorption-one-regeneration alternating operation mode. The VOCs concentration grade detection sensor is added to the front end of the five-segment transverse adsorption unit of the pretreatment module. The number of adsorption components is automatically switched according to the VOCs concentration range. 2-3 adsorption components are activated at low concentration, 3-4 adsorption components are activated at medium concentration, and all adsorption components are activated at high concentration. The low concentration is ≤50mg / m³, the medium concentration is 50-200mg / m³, and the high concentration is >200mg / m³. The airflow is switched by the electromagnetic valve group. The adsorption saturation time of a single adsorption component is ≥8h, and the regeneration time is ≤2h. The five-segment transverse adsorption unit (2) also includes an online regeneration component for adsorption materials, including a hot air backflush pipeline and a nitrogen purging system. The hot air temperature is controlled at 120-150℃, the backflush pressure is 0.3-0.5MPa, and the nitrogen purging flow rate is 5-8m³ / h. The regeneration mode is automatically switched according to the adsorption saturation of the adsorption component by the PLC controller. The regenerated adsorption material can be reused.

8. The electric heating combustion treatment device for lost foam casting tail gas according to claim 7, characterized in that: The combustion chamber of the direct-fired module is lined with refractory bricks, and the combustion temperature is controlled at 850-1100℃. The residence time of the exhaust gas in the combustion chamber is ≥2s. The electric heating component adopts a high-frequency induction heating or resistance heating structure and is equipped with a power adjustment module. The heating power can be automatically adapted according to the VOCs concentration and exhaust gas flow rate, with an adjustment range of 50-200kW, to ensure that the combustion chamber temperature is stably maintained at 850-1100℃. It also includes a safety protection component, which includes a temperature anomaly detector and an emergency power-off switch. The temperature anomaly detector is electrically connected to the emergency power-off switch, and when a temperature anomaly is detected, the electric heating power supply is cut off immediately.

9. The electric heating combustion treatment device for lost foam casting tail gas according to claim 8, characterized in that: It also includes a control system, which comprises a gas detection sensor, a temperature sensor, and a PLC controller. The gas detection sensor is installed in the intake and exhaust pipes to detect VOCs concentration, combustible gas concentration, and particulate matter concentration. The temperature sensor is installed in the direct combustion module and the heat recovery module. The PLC controller automatically adjusts the spray flow rate, electric heating power, valve opening, and UV lamp power based on the detection data. The PLC controller is equipped with a touch screen operating interface, which can display the operating parameters of each module in real time and has parameter alarm, historical data storage, and remote monitoring interface.

10. The electric heating combustion treatment device for lost foam casting tail gas according to claim 9, characterized in that: The anti-corrosion coating of the air intake pipe is made of polytetrafluoroethylene with a thickness of 1.5-2.0mm. The guide plate has an arc structure with an angle of 30-45° with the inner wall of the pipe. The spacing between adjacent guide plates is 1 / 3-1 / 2 of the pipe diameter. The surface of the guide plate is smooth. The deep processing module adopts a UV photocatalytic oxidation and low-temperature plasma synergistic purification structure. The UV lamp uses a dual-band combination of 254nm and 185nm wavelengths, and the plasma discharge power can be automatically adjusted according to the VOCs concentration.

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