A method for synergistically purifying barbecue oil fume particles and odor

Abstract

This invention relates to the field of oil fume purification, and discloses a method for the synergistic purification of particulate matter and odors from barbecue grill fumes. The method separately collects a first smoke stream formed by the volatilization of heated food surfaces above the grilling zone and a second smoke stream formed by the cracking of dripping grease from the heat source area or oil receiving area, maintaining separate transport during the pre-treatment stage. The first smoke stream is decelerated and guided by inertial separation, while the second smoke stream is subjected to swirling deceleration, wall contact, and cooling condensation. The two treated smoke streams are merged and balanced to form a main smoke stream. Bypass smoke is separated from the pre-treated first smoke stream, treated for active oxygen generation, and then reinjected into the main smoke stream. The main smoke stream is then subjected to low-temperature catalytic purification and tail-end interception treatment sequentially, and purged and regenerated using residual heat from the grill body or exhaust channel after grilling. This invention can simultaneously address particulate matter and odor issues, and improves the stability of subsequent purification stages.

Description

Technical Field

[0001] This invention relates to the field of oil fume purification, specifically to a method for the synergistic purification of particulate matter and odor from barbecue grill fumes. Background Technology

[0002] Barbecue grills are widely used in food processing and home cooking. During continuous heating, food releases volatile odor components, along with splattering oil, rising fumes, and particulate matter. To reduce smoke accumulation in the work area, existing barbecue equipment typically incorporates smoke collection structures above, to the side, or below the grill body, along with exhaust fans to vent the fumes for further processing.

[0003] In existing technologies, the treatment of barbecue fumes mostly involves guiding the collected fumes into a single path and then purifying them through mechanical filtration, water washing, electrostatic adsorption, catalytic decomposition, or adsorption deodorization. While this approach can reduce the amount of fumes generated during barbecuing to some extent, its front-end treatment is mostly aimed at the overall mixed fumes, lacking differentiated treatment for different fumes-generating locations, different pollutant compositions, and different phase characteristics.

[0004] However, during grilling, some of the smoke originates from the volatilization of food surfaces due to heat, while other smoke comes from the cracking of grease droplets after they fall onto the heat source or receiving area. These two types of smoke differ in oil droplet content, particle load, adhesion, and odor composition. Existing structures directly channel these smokes into the same path, making it easy for highly viscous tar and heavy oil mist to adhere and deposit in subsequent purification stages. This leads to increased flow resistance, increased susceptibility to contamination in the active treatment area, and difficulty in simultaneously addressing odor components and particulate matter, ultimately affecting the continuous stability of grilling smoke purification. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for the synergistic purification of particulate matter and odors from barbecue grill fumes, thereby resolving the technical problems existing in the prior art.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A method for synergistic purification of particulate matter and odor from barbecue grill fumes includes the following steps: S1: Collect the first smoke stream formed by the volatilization of food surface above the grilling area and the second smoke stream formed by the cracking of oil dripping from the heat source area or oil receiving area, and keep the first smoke stream and the second smoke stream transported separately in the front-end pre-treatment stage. S2: The first flue gas is decelerated, guided, and inertially separated to separate oil droplets and particulate matter in the first flue gas without actively cooling it. S3: The second flue gas is subjected to swirling deceleration, wall contact, and cooling condensation to deposit and remove tar, heavy oil mist and particulate matter in the second flue gas. The temperature of the second flue gas pretreatment process is lower than the temperature of the first flue gas pretreatment process. S4: The first flue gas stream processed in step S2 and the second flue gas stream processed in step S3 are merged and their flow and concentration are balanced to obtain the main flue gas stream. S5: Separate the bypass flue gas from the first flue gas after the treatment in step S2, treat the bypass flue gas with active oxygen generation, and then inject the generated active oxygen-containing gas flow into the main flue gas. S6: The main flue gas stream treated in step S5 will be subjected to low-temperature catalytic purification and tail-end interception treatment before being discharged. S7: After the barbecue is finished, use the residual heat of the barbecue oven or the exhaust channel to purge and regenerate the low-temperature catalytic purification part and the tail-end interception part in step S6.

[0007] Preferably, in S1, the smoke collection port for collecting the first smoke stream is located above the grilling area and facing the surface of the food, and the smoke collection port for collecting the second smoke stream is located above or to the side of the heat source area or the oil receiving area. The first smoke stream and the second smoke stream correspond to independently adjustable air intake channels. During the grilling process, the airflow of the second smoke stream corresponding to the exhaust path is adjusted based on at least two of the following: the temperature of the heat source area, the oil dripping frequency of the oil receiving area, the particulate matter concentration of the second smoke stream, and the pressure of the area corresponding to step S4. During the oil dripping and cracking stage, the airflow of the second smoke stream corresponding to the exhaust path is made to be greater than the airflow of the first smoke stream corresponding to the exhaust path.

[0008] Preferably, in step S2, the first flue gas flows sequentially through a guiding and diffusion treatment, an inertial collision treatment, and a first drainage treatment. The guiding and diffusion treatment reduces the flow velocity of the first flue gas by increasing the flow cross-section of the first flue gas. The inertial collision treatment causes oil droplets and particulate matter to detach from the airflow by changing the flow direction of the first flue gas. The first drainage treatment discharges the oil droplets and condensate separated by the aforementioned treatments along the first drainage path.

[0009] Preferably, in step S3, the second flue gas stream sequentially undergoes swirling flow guidance treatment, cooling deposition treatment, and second drainage treatment. The swirling flow guidance treatment causes the second flue gas stream to form a swirling flow. The cooling deposition treatment, through the cooperation between the oleophilic surface and the cooling wall surface, allows tar, heavy oil mist, and particulate matter to be deposited under centrifugal force, wall contact, and condensation. The second drainage treatment discharges the tar, heavy oil mist condensate, and particulate deposit liquid formed by the aforementioned treatments along the second drainage path. Furthermore, the second flue gas stream undergoes flame arrestor treatment before entering the corresponding area of ​​step S3.

[0010] Preferably, the first drainage path corresponding to step S2 and the second drainage path corresponding to step S3 are independent of each other. The sediment in the second drainage path is collected along the discharge direction and backmixing is suppressed from entering the treatment area corresponding to step S3. The first drainage path corresponding to step S2 is used to drain oil droplets and condensate with high fluidity, while the second drainage path corresponding to step S3 is used to drain tar condensate and particulate deposits with high viscosity.

[0011] Preferably, in step S4, after the first and second smoke streams merge, they undergo flow equalization treatment before entering the buffer volume for residence, and a main smoke stream is formed at the outlet of the buffer volume. The flow equalization treatment is used to reduce the local velocity difference between the first and second smoke streams at the merging point, and the buffer volume is used to reduce the flow rate fluctuation and pollutant concentration fluctuation of the main smoke stream.

[0012] Preferably, in step S5, the bypass flue gas is taken from the first flue gas stream after being processed in step S2. Before the active oxygen generation treatment, the bypass flue gas undergoes demisting treatment and liquid limiting treatment in sequence. The active oxygen generation treatment is carried out by dielectric barrier discharge to reduce the influence of droplet entrainment on the active oxygen generation process and to keep the generated active oxygen-containing treated gas stream continuously output before entering the main flue gas stream.

[0013] Preferably, in step S5, the gas flow containing active oxygen is injected into the main flue gas through multiple injection points distributed circumferentially along the main flue gas flow. The outlet direction of each injection point is intersected with the flow direction of the main flue gas flow, and the multiple injection points are staggered along the flow direction of the main flue gas flow, so that the gas flow containing active oxygen is dispersed and mixed before the main flue gas flow enters step S6.

[0014] Preferably, in step S6, the low-temperature catalytic purification employs a first catalytic treatment and a second catalytic treatment performed sequentially along the main flue gas flow direction. The first catalytic treatment is used to perform initial oxidation treatment on the main flue gas, and the second catalytic treatment is used to further catalytically decompose the intermediate products after initial oxidation. The tail-end interception treatment includes sequential active oxygen decomposition treatment and odor polishing treatment. The active oxygen decomposition treatment is used to decompose the active oxygen remaining after low-temperature catalytic purification, and the odor polishing treatment is used to further remove the remaining odor components.

[0015] Preferably, in step S7, when at least two of the following conditions are met: the operating pressure difference between the low-temperature catalytic purification section and the tail-end interception section is higher than the preset pressure difference value, the outlet odor signal is higher than the preset signal value, the cumulative running time reaches the preset time, or the furnace body temperature is higher than the preset regeneration temperature after grilling, purging regeneration is started. Before starting the purging and regeneration, first shut off the first and second flue gas streams entering the flue gas inlet path in step S4, and then open the regeneration gas path so that the purging and regeneration gas flows through the low-temperature catalytic purification section and the tail-end interception section in sequence; when the outlet odor signal drops below the preset recovery value and the operating pressure difference falls back to below the preset recovery pressure difference value, the purging and regeneration ends and the flue gas inlet path is restored.

[0016] In summary, the present invention has the following main beneficial effects: By separating the fumes generated during grilling into a first stream (formed by the volatilization of food surfaces due to heat) and a second stream (formed by the cracking of grease droplets), and ensuring that these two streams are transported separately during the pre-treatment stage, the system effectively addresses different sources of pollution. The first stream undergoes deceleration and inertial separation without active cooling, allowing entrained oil droplets and particulate matter to detach first, while odor components remain in the gaseous transport state required for subsequent treatment. Simultaneously, the second stream is treated with swirling deceleration, wall contact, and cooling condensation, causing tar, heavy oil mist, and high-load particulate matter to preferentially deposit and be removed before merging, thus reducing the high-viscosity pollution load at the front end. This avoids directly mixing the two types of fumes with significantly different pollution characteristics without differentiation, reducing the pollution pressure on subsequent purification stages and improving the overall targeting and stability of the purification path.

[0017] By separating bypass flue gas from the flue gas pretreated by the first flue gas stream, and then subjecting it to active oxygen generation treatment before reinjecting it into the main flue gas stream, the synergistic treatment capacity of odor components and residual organic pollutants is improved. By preferentially selecting the first flue gas stream, after initial reduction of oil droplets and particulate matter, as the bypass source, the flue gas entering the active oxygen generation zone carries lower droplet entrainment, thereby reducing the adhesion and contamination of the active oxygen generation zone by high-viscosity components. Furthermore, by injecting the active oxygen-treated gas stream into the homogenized main flue gas stream, the odor components and residual organic pollutants in the main flue gas stream receive pre-oxidation conditions before entering the low-temperature catalytic purification section, achieving the goal of reducing the load on subsequent catalytic treatment and improving synergistic purification efficiency. Therefore, this application distinguishes itself from treatment methods that directly introduce oxidizing gases into the high-oil-load total flue gas stream, reducing the problems of active oxygen generation zone failure and uneven mixing.

[0018] By sequentially implementing low-temperature catalytic purification, tail-end interception, and post-barbecue waste heat purging and regeneration at the rear end of the main flue gas flow, the continuous working capacity of the subsequent purification stages is improved. Low-temperature catalytic purification further decomposes pollutants after synergistic oxidation, while tail-end interception continues to treat residual active oxygen and incompletely removed odor components, thereby reducing residual odors and oxidizing components in emissions. Simultaneously, by closing the flue gas inlet path after barbecuing and utilizing the waste heat from the furnace or exhaust channel to purge and regenerate the low-temperature catalytic purification and tail-end interception stages, the subsequent purification capacity is restored without additional oil fume interference. This mitigates the increase in resistance and efficiency decline in subsequent purification stages caused by long-term oil fume pollution, improving the reusability and continuous operation capability of the entire purification system. Attached Figure Description

[0019] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram of the separate source collection and front-end branching of the first and second smoke streams in this invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 refer to Figure 1-2 A method for synergistic purification of particulate matter and odor from barbecue grill fumes includes the following steps: S1: Collect the first smoke stream formed by the volatilization of food surface above the grilling area and the second smoke stream formed by the cracking of oil dripping from the heat source area or oil receiving area, and keep the first smoke stream and the second smoke stream transported separately in the front-end pre-treatment stage. S2: The first flue gas is decelerated, guided, and inertially separated to separate oil droplets and particulate matter in the first flue gas without actively cooling it. S3: The second flue gas is subjected to swirling deceleration, wall contact, and cooling condensation to deposit and remove tar, heavy oil mist and particulate matter in the second flue gas. The temperature of the second flue gas pretreatment process is lower than the temperature of the first flue gas pretreatment process. S4: The first flue gas stream processed in step S2 and the second flue gas stream processed in step S3 are merged and their flow and concentration are balanced to obtain the main flue gas stream. S5: Separate the bypass flue gas from the first flue gas after the treatment in step S2, treat the bypass flue gas with active oxygen generation, and then inject the generated active oxygen-containing gas flow into the main flue gas. S6: The main flue gas stream treated in step S5 will be subjected to low-temperature catalytic purification and tail-end interception treatment before being discharged. S7: After the barbecue is finished, use the residual heat of the barbecue oven or the exhaust channel to purge and regenerate the low-temperature catalytic purification part and the tail-end interception part in step S6.

[0022] The smoke produced during grilling is not a homogeneous smoke from a single source, but rather comprises at least two types of smoke with different formation mechanisms and pollution characteristics. One type is the smoke formed by the volatilization of food surfaces after heating. This type of smoke has a higher proportion of odor components and carries a certain amount of oil droplets and particulate matter, but its overall adhesion is relatively low; this type of smoke is defined as the first smoke stream. The other type is the smoke formed by the decomposition of grease dripping onto the heat source area or oil receiving area. This type of smoke has a higher content of tar, heavy oil mist, and particulate matter, stronger adhesion, and exhibits more pronounced instantaneous fluctuations when oil dripping intensifies; this type of smoke is defined as the second smoke stream. Based on these differences, this embodiment does not immediately merge the two types of smoke after their formation and purify them uniformly through the same path. Instead, in the front-end pretreatment stage, the first and second smoke streams are transported separately, and each type of smoke is treated according to its source and phase differences. They are then merged at the back end for coordinated purification. This setting allows highly viscous components, which are most likely to contaminate subsequent purification stages, to be preferentially reduced before merging, thereby reducing the load on subsequent purification stages and improving the stability of subsequent purification.

[0023] In step S1, the first smoke stream formed by the evaporation of heated food from the surface above the grilling zone, and the second smoke stream formed by the cracking of dripping grease from the heat source area or oil receiving area are collected separately and transported separately during the pre-treatment stage. Specifically, the smoke collection port for the first smoke stream is positioned above the grilling zone and facing the food surface, allowing the smoke from the evaporation of heated food to preferentially enter the corresponding path of the first smoke stream. The smoke collection port for the second smoke stream is positioned above or to the side of the heat source area or oil receiving area, allowing the high-load smoke formed after the cracking of dripping grease to be preferentially extracted near its generation location. The first and second smoke streams each correspond to independently adjustable exhaust paths to adjust the extraction intensity according to the fluctuation characteristics of the two types of smoke. Furthermore, during the grilling process, the airflow rate of the ventilation path corresponding to the second smoke stream can be adjusted based on at least two of the following: the temperature of the heat source area, the oil dripping frequency of the oil receiving area, the particulate matter concentration of the second smoke stream, and the pressure at the confluence area or buffer volume in step S4. During the oil dripping pyrolysis stage, the airflow rate of the ventilation path corresponding to the second smoke stream is made greater than that of the ventilation path corresponding to the first smoke stream. The working principle is that tar and heavy oil mist in the second smoke stream increase rapidly during the oil dripping pyrolysis stage. If they are not preferentially extracted near their generation location, they easily diffuse backward and contaminate other channels. By giving the second smoke stream a higher airflow priority during this stage, high-load pollutants can preferentially enter the second smoke stream pretreatment path. Through the above-mentioned source-separated collection and differentiated airflow control, it is possible to avoid directly mixing smoke gases with significantly different sources and properties at the front end, providing a prerequisite for subsequent differentiated pretreatment. This is also an important basis for this embodiment, which differs from the scheme of uniformly introducing grilling smoke into a single path for treatment.

[0024] In step S2, the first flue gas stream is decelerated and guided, and subjected to inertial separation. Without actively cooling the first flue gas stream, oil droplets and particulate matter are separated from it. Specifically, the first flue gas stream sequentially undergoes a guiding and diffusion treatment, an inertial collision treatment, and a first drainage treatment. The guiding and diffusion treatment reduces the flow velocity of the first flue gas stream by increasing its cross-section, making it easier for larger oil droplets and particulate matter to detach from the main airflow after the velocity decreases. The inertial collision treatment changes the flow direction of the first flue gas stream, causing oil droplets and particulate matter to deviate from the gas phase flow path due to inertial differences and achieve separation. The first drainage treatment discharges the separated oil droplets and condensate along a first drainage path. It should be noted that in this embodiment, the first flue gas stream is not actively cooled. This is not a simple omission of the heat exchange structure, but a targeted design based on the pollution phase characteristics of the first flue gas stream. The odor components in the first flue gas stream are mainly gaseous. If they are actively cooled at the front end, some semi-volatile components may condense prematurely and form an adhesion layer on the channel wall. This not only increases the front-end resistance but also increases the entrainment of liquid droplets in the bypass flue gas, which is detrimental to the subsequent active oxygen generation treatment. Therefore, this embodiment uses only deceleration and inertial separation to preferentially remove oil droplets and particulate matter without actively interrupting the gas phase transport. This setting reduces the liquid load in the first flue gas stream and provides a lower liquid droplet entrainment source for the subsequent bypass flue gas extraction from the first flue gas stream, thereby improving the stability of the subsequent active oxygen generation treatment.

[0025] In step S3, the second flue gas undergoes swirling deceleration, wall contact, and cooling condensation to deposit and remove tar, heavy oil mist, and particulate matter. The temperature during the pretreatment of the second flue gas is lower than that during the pretreatment of the first flue gas. Specifically, before entering the swirling guidance treatment and cooling deposition treatment, the second flue gas undergoes flame arrestor treatment to suppress flames, high-temperature sparks, or localized backfire from the heat source area from entering the subsequent cooling zone. Subsequently, the second flue gas sequentially undergoes swirling guidance treatment, cooling deposition treatment, and second drainage treatment. The swirling guidance treatment creates a swirling flow in the second flue gas, using centrifugal force to promote the migration of tar, heavy oil mist, and particulate matter towards the channel wall. The cooling deposition treatment, through the interaction of the oleophilic surface and the cooling wall, allows the highly viscous components that have migrated to the wall to further deposit under wall contact and condensation. The second drainage treatment removes the formed tar condensate, heavy oil mist condensate, and particulate deposit liquid along the second drainage path. The second flue gas stream is actively cooled because the main components most likely to cause subsequent purification failures are not general odor gases, but rather high-viscosity tar and heavy oil mist. If these components are not preferentially deposited and removed before merging, they will easily cover the reaction surface or block the flow channel after entering the subsequent active oxygen generation and low-temperature catalytic purification areas, leading to a decrease in purification efficiency. By introducing a combination of swirling deceleration, wall contact, and cooling condensation on the second flue gas side, instead of simply cooling the flue gas, the higher adhesion tendency of the high-viscosity components of the second flue gas to the low-temperature wall surface is utilized, causing them to preferentially detach from the gas phase flow path before merging. Thus, the first and second flue gas streams employ two different mechanism treatment paths at the front end: inertial separation without active cooling and swirling deposition with active cooling. This creates differentiated pretreatment mechanisms, avoiding the conventional approach of treating both flue gas streams uniformly.

[0026] Furthermore, the first drainage path corresponding to step S2 and the second drainage path corresponding to step S3 are independent of each other. The oil droplets and condensate discharged in step S2 are discharged through the first drainage path, while the tar, heavy oil mist condensate, and particulate sediment discharged in step S3 are discharged through the second drainage path. Since the liquid separated from the first flue gas has high fluidity, while the liquid separated from the second flue gas has higher viscosity, if the two share a drainage path, cross-contamination, backmixing, or local sludge accumulation is likely to occur. Therefore, in this embodiment, the first and second drainage paths are designed to handle the discharge of liquids with different properties. Specifically, the sediment in the second drainage path collects along the discharge direction and suppresses backmixing into the treatment area corresponding to step S3. Specifically, the second drainage path can be designed with a continuous slope along the discharge direction and a gradually increasing local cross-section to allow the viscous sediment to continuously collect towards the discharge end under gravity. By discharging the two types of separated liquids separately, the mutual interference between liquids with different properties can be reduced, and the possibility of the high-viscosity sediment from the second flue gas side returning to the treatment area can be decreased. By setting up the above-mentioned drainage path separation, the front-end pretreatment can not only complete the initial separation of the gas phase and the liquid phase, but also form an independent discharge path suitable for sediments of different properties, thereby further improving the continuous operation capability of the front-end pretreatment.

[0027] In step S4, the first flue gas stream processed in step S2 and the second flue gas stream processed in step S3 are merged, and flow and concentration are equalized to obtain the main flue gas stream. Specifically, after merging, the first and second flue gas streams undergo flow equalization before entering a buffer volume for residence, forming the main flue gas stream at the buffer volume outlet. Flow equalization reduces the local velocity difference between the first and second flue gas streams at the merging point, ensuring a more uniform flow field before entering the buffer volume. The buffer volume reduces flow fluctuations and pollutant concentration fluctuations in the main flue gas stream. The working principle is that during grilling operations, flipping, brushing oil, changes in heating intensity, and oil dripping frequency cause the two flue gas streams to exhibit pulse-like changes. If these are directly sent to the subsequent active oxygen generation and reinjection and low-temperature catalytic purification areas, it can easily cause a short-term surge in the load on the subsequent treatment stages. By first equalizing the flow and then buffering, the two flue gas streams, after differentiated front-end treatment, form a relatively stable main flue gas stream before entering the subsequent collaborative purification stage. This reduces the impact of instantaneous fluctuations on the subsequent purification stage, thereby improving the overall operational stability.

[0028] In step S5, bypass flue gas is separated from the first flue gas stream after treatment in step S2. After the bypass flue gas undergoes active oxygen generation treatment, the generated active oxygen-containing gas stream is injected into the main flue gas stream. The bypass flue gas is taken from the first flue gas stream after treatment in step S2, rather than from the second flue gas stream or the main flue gas stream formed in step S4. This is a key implementation point of this embodiment. The first flue gas stream after treatment in step S2 has already undergone preliminary separation of oil droplets and particulate matter, with relatively few droplet entrainment, making it more suitable as the intake source for active oxygen generation treatment. If taken from the second flue gas stream, tar and heavy oil mist can easily enter the active oxygen generation area and contaminate the discharge interface. If taken from the main flue gas stream before further purification, although the main flue gas stream has undergone flow equalization buffering, it still contains residual components from the second flue gas stream after treatment in step S3, and the overall droplet and heavy component load is still higher than that of the first flue gas stream after treatment in step S2. Therefore, this embodiment explicitly limits the source of the bypass flue gas to the first flue gas stream after treatment in step S2. Furthermore, the bypass flue gas undergoes demisting and liquid limiting treatment before being treated for active oxygen generation. This reduces the impact of droplet entrainment on the active oxygen generation process and ensures continuous output of the generated active oxygen-containing treated gas flow before it enters the main flue gas flow. The active oxygen generation treatment employs a dielectric barrier discharge method. Its working principle is that dielectric barrier discharge is more suitable for continuously forming an active oxygen-containing treated gas flow under relatively low droplet load conditions, without requiring the discharge area to be directly placed in the high oil load main flue gas flow. This arrangement reduces the risk of high-viscosity components depositing at the discharge interface and improves the stability of active oxygen generation.

[0029] Furthermore, in step S5, the oxygen-containing gas stream is injected into the main flue gas through multiple injection points distributed circumferentially along the main flue gas flow. The outlet direction of each injection point intersects with the flow direction of the main flue gas flow, and the multiple injection points are staggered along the flow direction of the main flue gas flow to ensure that the oxygen-containing gas stream is dispersed and mixed before entering step S6. The working principle is that if only a single point injection is used, the oxygen-containing gas stream in the main flue gas flow is prone to forming a situation where the concentration is high in some areas and low in other areas, resulting in uneven synergistic oxidation. By using multiple injection points distributed circumferentially and staggered, the oxygen-containing gas stream can diffuse and mix more evenly within the cross-sectional area of ​​the main flue gas flow, thereby enabling odor components and residual organic pollutants in the main flue gas flow to obtain more uniform pre-oxidation conditions before entering the low-temperature catalytic purification. By limiting the source of bypass flue gas to the first flue gas stream after step S2, and further adopting a multi-point dispersion mixing method at the reinjection end, this embodiment not only solves the problem of the active oxygen generation area being susceptible to high viscosity pollution, but also avoids the defect of uneven mixing at a single point reinjection, thus forming a substantial difference from the conventional scheme of directly introducing ozone or other oxidizing gases into the main flue.

[0030] In step S6, the main flue gas stream treated in step S5 is sequentially subjected to low-temperature catalytic purification and tail-end interception treatment before being discharged. Specifically, the low-temperature catalytic purification employs a first catalytic treatment and a second catalytic treatment performed sequentially along the main flue gas flow direction. The first catalytic treatment initiates oxidation of the main flue gas stream, allowing odor components and residual organic pollutants treated with active oxygen to undergo initial oxidation reactions. The second catalytic treatment further decomposes the intermediate products after initial oxidation, reducing the load on the tail-end interception treatment. The tail-end interception treatment includes sequential active oxygen decomposition and odor polishing. The active oxygen decomposition decomposes residual active oxygen after low-temperature catalytic purification, while the odor polishing further removes remaining odor components. This two-stage catalytic purification followed by two-stage tail-end treatment creates a continuous purification chain between the initial synergistic oxidation and the mid-stage catalytic decomposition, while the subsequent active oxygen decomposition and odor polishing remove residual oxidizing components and supplement residual odors, respectively. Therefore, step S6 is not simply a series of conventional purification units connected in series, but rather a sequential connection based on the results of the differentiated pretreatment at the front end and the reactive oxygen synergistic oxidation in step S5, allowing the low-temperature catalytic purification and the tail-end interception treatment to each undertake the purification function at different stages. Through this setup, the burden of a single purification unit on the total pollution load can be reduced, improving the stability of the overall purification chain.

[0031] In step S7, after grilling, the residual heat of the grill body or the exhaust channel is used to purge and regenerate the low-temperature catalytic purification section and the tail-end interception section in step S6. Specifically, purging and regeneration are initiated when at least two of the following conditions are met: the operating pressure difference between the low-temperature catalytic purification section and the tail-end interception section is higher than a preset pressure difference value; the outlet odor signal is higher than a preset signal value; the cumulative running time reaches a preset time; or the grill body temperature after grilling is higher than a preset regeneration temperature. Before initiating purging and regeneration, the first and second smoke flows into the smoke inlet path of step S4 are closed, and then the regeneration gas path is opened, so that the purging and regeneration gas flows sequentially through the low-temperature catalytic purification section and the tail-end interception section. After entering through the regeneration inlet, the regeneration gas first flows through the low-temperature catalytic purification section, then through the tail-end interception section, and finally exits from the regeneration exhaust end. Its working principle is as follows: before regeneration, the flue gas inlet path is closed to prevent new oil fumes from continuously entering the downstream purification section during regeneration. This allows the regeneration gas to purge and thermally restore the downstream section with less interference. The regeneration gas preferentially flows through the low-temperature catalytic purification section and then through the tail-end interception section, allowing the catalytic surface to first undergo residual heat cleaning and purging recovery before further desorption and recovery of the tail-end interception section. When regeneration ends, purging regeneration ends and the flue gas inlet path is restored when the outlet odor signal drops below the preset recovery value and the operating differential pressure falls below the preset recovery differential pressure value. By controlling the timing of closing the flue gas inlet before opening regeneration and restoring the flue gas inlet only after the recovery conditions are met, mutual interference between the regeneration and normal purification processes can be avoided, improving the reusability stability of the downstream purification section.

[0032] It should be further explained that the thresholds and control conditions in this embodiment do not depend on a specific complex algorithm, but can be pre-calibrated according to different barbecue oven types, design air volume, heat source power, and emission targets. During calibration, the temperature threshold of the heat source area, the dripping oil frequency threshold, the second flue gas particulate matter concentration threshold, the pressure threshold of the area corresponding to step S4, the operating pressure difference threshold, the regeneration temperature threshold, and the odor recovery threshold can be determined through actual operation tests. The calibration principle is to ensure the continuity of the barbecue operation, so that the second flue gas is preferentially extracted when the dripping oil pyrolysis is enhanced, so that the first flue gas has completed the oil droplet reduction before becoming a bypass flue gas source, and so that the resistance growth rate and odor release risk of the subsequent low-temperature catalytic purification part and the tail-end interception part are kept within an acceptable range. Since the core improvement of this application lies in the differentiated pretreatment of the two types of flue gas, the bypass active oxygen generation of the first flue gas after step S2 treatment, and the subsequent regeneration sequence, rather than in a specific complex algorithm, this embodiment does not use a specific mathematical model as a necessary limitation, but ensures feasibility through a clear process path and action relationship.

[0033] The complete working process of this embodiment is as follows: After the grilling begins, the first smoke stream and the second smoke stream are collected through the first smoke collection path and the second smoke collection path, respectively; the first smoke stream completes deceleration and guidance, inertial separation, and first drainage discharge without active cooling, prioritizing the removal of oil droplets and particulate matter; the second smoke stream, after undergoing flame-retardant treatment, completes swirling guidance, cooling deposition, and second drainage discharge, prioritizing the reduction of tar, heavy oil mist, and particulate deposits; subsequently, in step S4, the two smoke streams are first evenly distributed and then buffered, forming the main smoke stream at the outlet of the buffer volume; and so on. During the process, bypass flue gas is extracted from the first flue gas stream after step S2. After demisting, liquid limiting, and dielectric barrier discharge treatment, it forms a gas flow containing active oxygen, which is then injected into the main flue gas stream through multiple injection points. The main flue gas stream continues to pass through the first catalytic treatment, the second catalytic treatment, the active oxygen decomposition treatment, and the odor polishing treatment in sequence before being discharged. After the grilling is completed, the flue gas inlet path is closed and the regeneration gas path is opened. The residual heat of the furnace body or the residual heat of the exhaust channel is used to purge and regenerate the low-temperature catalytic purification part and the tail-end interception part. After the recovery conditions are met, the regeneration is ended and the flue gas inlet path is restored.

[0034] Compared to methods that directly merge and uniformly treat barbecue fumes after generation with water washing, electrostatic dust removal, photolysis, or simple adsorption, this embodiment maintains separate first and second flue gas streams in the pretreatment stage. Two different treatment mechanisms are employed: inertial separation without active cooling and swirling deposition with active cooling. This differentiates the components most likely to affect the stability of subsequent purification before merging. Furthermore, this embodiment does not directly treat reactive oxygen species (ROS) generation in the high-oil-load total flue gas stream. Instead, it extracts bypass flue gas from the first flue gas stream after step S2 for ROS generation treatment and then reinjects it into the main flue gas stream through multiple injection points. This reduces the pollution of the ROS generation area by high-viscosity deposits and improves mixing uniformity. Moreover, after barbecue, this embodiment first closes the smoke inlet path and then uses residual heat for purging and regeneration, allowing the subsequent purification units to restore their purification capacity without additional oil fume interference. By coordinating the above-mentioned process sequence and processing path, not only is a clear sequential relationship formed between each step, but also those skilled in the art can directly implement the method of this application based on this embodiment. At the same time, this application is fundamentally different from existing solutions that uniformly pre-treat barbecue fumes, uniformly supply oxidizing gases, or uniformly regenerate them at the back end.

[0035] During grilling, the first smoke stream formed by the volatilization of food surfaces due to heat and the second smoke stream formed by the decomposition of grease droplets differ in their pollution composition and phase characteristics. The first smoke stream contains a higher proportion of odor components, while the second smoke stream has a higher load of tar, heavy oil mist, and particulate matter. Therefore, this application first collects the first and second smoke streams separately and implements differentiated front-end pretreatment for each. The first smoke stream undergoes deceleration and inertial separation without active cooling to preferentially remove oil droplets and particulate matter, reducing droplet entrainment in subsequent bypass flue gas. The second smoke stream undergoes swirling deceleration, wall contact, and cooling condensation to preferentially deposit and remove tar, heavy oil mist, and particulate matter, thereby reducing high-viscosity components that significantly impact subsequent purification stages before the two smoke streams merge.

[0036] After pretreatment, the first and second flue gas streams merge to form the main flue gas stream. Simultaneously, bypass flue gas is separated from the first flue gas stream after treatment in step S2. This bypass gas undergoes demisting, liquid limiting, and active oxygen generation treatment before being reinjected into the main flue gas stream. This allows odor components and residual organic pollutants in the main flue gas stream to undergo synergistic oxidation, followed by low-temperature catalytic purification and tail-end interception treatment for further decomposition and removal. After grilling, the smoke inlet path is closed, and the residual heat from the furnace or exhaust channel is used to purge and regenerate the low-temperature catalytic purification and tail-end interception sections, restoring the purification capacity of the downstream purification sections without additional oil fume interference. Through this process, this application achieves synergistic purification of particulate matter and odors from barbecue grill fumes and improves the operational stability and continuous working capacity of the downstream purification sections.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for synergistic purification of particulate matter and odor from barbecue grill fumes, characterized in that, Includes the following steps: S1: Collect the first smoke stream formed by the volatilization of food surface above the grilling area and the second smoke stream formed by the cracking of oil dripping from the heat source area or oil receiving area, and keep the first smoke stream and the second smoke stream transported separately in the front-end pre-treatment stage. S2: The first flue gas is decelerated, guided, and inertially separated to separate oil droplets and particulate matter in the first flue gas without actively cooling it. S3: The second flue gas is subjected to swirling deceleration, wall contact, and cooling condensation to deposit and remove tar, heavy oil mist and particulate matter in the second flue gas. The temperature of the second flue gas pretreatment process is lower than the temperature of the first flue gas pretreatment process. S4: The first flue gas stream processed in step S2 and the second flue gas stream processed in step S3 are merged and their flow and concentration are balanced to obtain the main flue gas stream. S5: Separate the bypass flue gas from the first flue gas after the treatment in step S2, treat the bypass flue gas with active oxygen generation, and then inject the generated active oxygen-containing gas flow into the main flue gas. S6: The main flue gas stream treated in step S5 will be subjected to low-temperature catalytic purification and tail-end interception treatment before being discharged. S7: After the barbecue is finished, use the residual heat of the barbecue oven or the exhaust channel to purge and regenerate the low-temperature catalytic purification part and the tail-end interception part in step S6.

2. The method for synergistic purification of particulate matter and odor from barbecue grill fumes according to claim 1, characterized in that, In S1, the smoke collection port for collecting the first smoke stream is set above the grilling area and facing the surface of the food, and the smoke collection port for collecting the second smoke stream is set above or to the side of the heat source area or the oil receiving area. The first smoke stream and the second smoke stream correspond to independently adjustable air intake channels. During the grilling process, the airflow of the second smoke stream corresponding to the exhaust path is adjusted based on at least two of the following: the temperature of the heat source area, the oil dripping frequency of the oil receiving area, the particulate matter concentration of the second smoke stream, and the pressure of the area corresponding to step S4. During the oil dripping and cracking stage, the airflow of the second smoke stream corresponding to the exhaust path is made to be greater than the airflow of the first smoke stream corresponding to the exhaust path.

3. The method for synergistic purification of particulate matter and odor from barbecue grill fumes according to claim 2, characterized in that, In step S2, the first flue gas flows through a flow-guiding and diffusion process, an inertial collision process, and a first drainage process in sequence. The flow-guiding and diffusion process reduces the flow velocity of the first flue gas by increasing the flow cross-section of the first flue gas. The inertial collision process causes oil droplets and particulate matter to separate from the airflow by changing the flow direction of the first flue gas. The first drainage process discharges the oil droplets and condensate separated by the aforementioned processes along the first drainage path.

4. The method for synergistic purification of particulate matter and odor from barbecue grill fumes according to claim 3, characterized in that, In step S3, the second flue gas stream sequentially undergoes swirling flow guidance treatment, cooling deposition treatment, and second drainage treatment. The swirling flow guidance treatment causes the second flue gas stream to form a swirling flow. The cooling deposition treatment, through the cooperation between the oleophilic surface and the cooling wall surface, allows tar, heavy oil mist, and particulate matter to be deposited under centrifugal force, wall contact, and condensation. The second drainage treatment discharges the tar, heavy oil mist condensate, and particulate deposit liquid formed by the aforementioned treatments along the second drainage path. Furthermore, the second flue gas stream undergoes flame arrestor treatment before entering the corresponding area of ​​step S3.

5. The method for synergistic purification of particulate matter and odor from barbecue grill fumes according to claim 4, characterized in that, The first drainage path corresponding to step S2 and the second drainage path corresponding to step S3 are independent of each other. The sediment in the second drainage path is collected along the discharge direction and backmixing is suppressed from entering the treatment area corresponding to step S3. The first drainage path corresponding to step S2 is used to drain oil droplets and condensate with high fluidity, while the second drainage path corresponding to step S3 is used to drain tar condensate and particulate deposits with high viscosity.

6. The method for synergistic purification of particulate matter and odor from barbecue grill fumes according to claim 5, characterized in that, In step S4, after the first and second flue streams merge, they undergo flow equalization treatment before entering the buffer volume for residence. The main flue stream is then formed at the outlet of the buffer volume. The flow equalization treatment is used to reduce the local velocity difference between the first and second flue streams at the merging point, and the buffer volume is used to reduce the flow rate fluctuation and pollutant concentration fluctuation of the main flue stream.

7. The method for synergistic purification of particulate matter and odor from barbecue grill fumes according to claim 6, characterized in that, In step S5, the bypass flue gas is taken from the first flue gas stream after being processed in step S2. Before the active oxygen generation treatment, the bypass flue gas undergoes demisting treatment and liquid limiting treatment in sequence. The active oxygen generation treatment is carried out by dielectric barrier discharge mode to reduce the influence of droplet entrainment on the active oxygen generation process and to keep the generated active oxygen-containing treated gas flow continuously output before entering the main flue gas stream.

8. The method for synergistic purification of particulate matter and odor from barbecue grill fumes according to claim 7, characterized in that, In step S5, the gas flow containing active oxygen is injected into the main flue gas through multiple injection points distributed circumferentially along the main flue gas flow. The outlet direction of each injection point is intersected with the flow direction of the main flue gas flow, and the multiple injection points are staggered along the flow direction of the main flue gas flow so that the gas flow containing active oxygen is dispersed and mixed before the main flue gas flow enters step S6.

9. The method for synergistic purification of particulate matter and odor from barbecue grill fumes according to claim 8, characterized in that, In step S6, the low-temperature catalytic purification employs a first catalytic treatment and a second catalytic treatment performed sequentially along the main flue gas flow direction. The first catalytic treatment is used to perform initial oxidation treatment on the main flue gas, and the second catalytic treatment is used to further catalytically decompose the intermediate products after initial oxidation. The tail-end interception treatment includes sequential active oxygen decomposition treatment and odor polishing treatment. The active oxygen decomposition treatment is used to decompose the active oxygen remaining after low-temperature catalytic purification, and the odor polishing treatment is used to further remove the remaining odor components.

10. The method for synergistic purification of particulate matter and odor from barbecue grill fumes according to claim 9, characterized in that, In step S7, when at least two of the following conditions are met: the operating pressure difference between the low-temperature catalytic purification section and the tail-end interception section is higher than the preset pressure difference value, the outlet odor signal is higher than the preset signal value, the cumulative running time reaches the preset time, or the furnace body temperature is higher than the preset regeneration temperature after grilling, purging regeneration is started. Before starting the purging and regeneration, first shut off the first and second flue gas streams entering the flue gas inlet path in step S4, and then open the regeneration gas path so that the purging and regeneration gas flows through the low-temperature catalytic purification section and the tail-end interception section in sequence; when the outlet odor signal drops below the preset recovery value and the operating pressure difference falls back to below the preset recovery pressure difference value, the purging and regeneration ends and the flue gas inlet path is restored.

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