Treatment of oil-containing exhaust gas and method for operating the same

Abstract

This invention relates to the field of oily exhaust gas treatment, and discloses an apparatus for treating oily exhaust gas and its operating method. The apparatus includes: a condenser and an absorption tower; the condenser is used to condense the oily exhaust gas to obtain non-condensable gas; the absorption tower is used to absorb the oil in the non-condensable gas using an absorbent liquid, resulting in exhaust gas and an oil-water mixture; wherein, a baffle is installed inside the absorption tower, and the baffle is inclined downwards relative to the horizontal line at an angle of 5-45°. The method provided by this invention can ensure that the exhaust gas always meets emission standards under long-term operation.

Description

Technical Field

[0001] This invention relates to the field of oily exhaust gas treatment, and more specifically to an oily exhaust gas treatment device and its operation method. Background Technology

[0002] Chemical industrial production inevitably generates waste gas and pollutants. Most of these wastes are harmful at certain concentrations, some even being highly toxic substances, and their entry into the environment will cause pollution. According to the form of the pollutants, they can be categorized as waste gas, wastewater, and waste residue, all of which pollute both water and air.

[0003] As the oily exhaust gas is absorbed and treated by the absorption tower, the oil content in the water gradually increases with long-term operation. The oil and water phases will separate in the bottom of the absorption tower. The oil phase in the upper part is carried away by the exhaust gas at the inlet of the absorption tower, resulting in the oil content in the exhaust gas of the absorption tower exceeding the standard, which leads to environmental pollution and other problems. Therefore, the treatment of this oily exhaust gas is an urgent problem to be solved.

[0004] CN115738576A discloses a tail gas treatment system and process containing volatile organic compounds. The process mainly includes a condensation module and an absorption module. The condensation module includes multi-stage condensation, and the absorption module has an absorbent liquid nozzle to allow the tail gas entering the absorption module to contact the absorbent liquid. This patent application can effectively recover most of the methanol in methanol tail gas. However, this patent is aimed at the treatment of oily tail gas, which is almost insoluble in water. Therefore, this treatment process cannot be effectively used for the treatment of this tail gas.

[0005] CN219399536U discloses a benzene-containing VOC tail gas recovery system. This system includes multi-stage condensation, primarily for benzene recovery, and specifically addresses the blockage issue that occurs during prolonged condensation operation. The entire tail gas treatment system can continuously process tail gas without shutdown, while also ensuring the normal recovery of benzene compounds in the tail gas. In this invention, unrecovered tail gas is mainly treated by adsorption to meet standards and recovers most of the benzene. However, oily substances cannot be reused in this invention, and the raw materials contain water, which affects the adsorption effect.

[0006] CN210229510U discloses an oil-containing exhaust gas purification device. The device mainly includes an air purification chamber and a liquid purification chamber. This utility model reduces the emission of hazardous exhaust gases, eliminates the safety hazards of oil and gas drifting and depositing on the surface of surrounding equipment, and reduces the oil content in the gas from 38% to 5%. However, this process does not effectively reduce the oil content in the exhaust gas before liquid absorption, resulting in an increase in the amount of oil-containing liquid to be processed. Furthermore, the high oil content in the liquid will significantly reduce the absorption efficiency. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem in existing technologies where, during the treatment of oily exhaust gas, as the oil content in the absorbent increases and the oil phase separates from the water phase at the bottom of the absorption tower, the gas phase entering the absorption tower carries upper layer oil to the exhaust gas outlet, causing the exhaust gas content to exceed the standard. This invention provides a treatment device for oily exhaust gas and its operating method. The method provided by this invention can ensure that the exhaust gas always meets emission standards under long-term operation.

[0008] To achieve the above objectives, the first aspect of the present invention provides an apparatus for treating oily exhaust gas, the apparatus comprising: a condensation device and an absorption tower; The condensation equipment is used to condense oily exhaust gas to obtain non-condensable gas; The absorption tower is used to absorb the oil in the non-condensable gas using an absorbent liquid, to obtain exhaust gas and an oil-water mixture; The absorption tower is equipped with a baffle that is tilted downwards relative to the horizontal line at an angle of 5-45°.

[0009] A second aspect of the present invention provides a method for operating the processing apparatus described in the first aspect, the method comprising: (1) The oily exhaust gas is condensed to obtain non-condensable gas; (2) The oil in the non-condensable gas is absorbed by an absorbent to obtain an exhaust gas and an oil-water mixture; wherein the concentration of VOC in the exhaust gas is not higher than 0.1 mg / L.

[0010] The beneficial effects of the present invention through the above technical solution include: In the method provided by this invention, the oily exhaust gas is condensed by a condenser to remove most of the oily substances from the exhaust gas, and the non-condensable gas enters an absorption tower for further treatment. As the non-condensable gas enters the absorption tower, it rises through the tower, and under the action of specific baffles, the amount of volatile oil carried by the gas to the gas phase outlet of the absorption tower, thus reducing the risk of the exhaust gas content exceeding the standard, is effectively reduced.

[0011] In a preferred configuration, an oil-water separator is connected to the bottom of the absorber, preventing the accumulation of oil-water mixture in the absorber bottom and effectively avoiding the entrainment of the upper oil phase by the gas after oil-water stratification. Furthermore, the oil-water mixture undergoes pre-separation and separation via the oil-water separator and oil-water pre-separation tank, further reducing the volatile oil content in the circulating absorbent, which is then returned to the absorber for reuse. With prolonged operation, the oil content in the absorbent does not increase significantly, further reducing the entrainment of volatile oil by the gas to the absorber's gas phase outlet, thus achieving emission standards. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the device provided by the present invention.

[0013] Explanation of reference numerals in the attached figures Detailed Implementation

[0014] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0015] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "vertical," "horizontal," "top," "bottom," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and 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, and therefore should not be construed as a limitation of the invention. Furthermore, "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0016] In this invention, the terms "first" and "second" do not limit the substances and operations, but are only used to distinguish the substances introduced in different steps and the operations performed in different stages.

[0017] The first aspect of the present invention provides an apparatus for treating oily exhaust gas, the apparatus comprising: a condensation device and an absorption tower; The condensation equipment is used to condense oily exhaust gas to obtain non-condensable gas; The absorption tower is used to absorb the oil in the non-condensable gas using an absorbent liquid, to obtain exhaust gas and an oil-water mixture; The absorption tower is equipped with a baffle that is tilted downwards relative to the horizontal line at an angle of 5-45°.

[0018] In this invention, the oily exhaust gas is first condensed by a condensation device to remove most of the oily substances in the exhaust gas. This allows the oily substances in the oily exhaust gas to be condensed and reused. It can reduce the oil phase content in the non-condensable gas entering the absorption tower, reduce the processing pressure of the absorption tower, and reduce the amount of waste liquid generated.

[0019] In this invention, the baffle is tilted downwards at an angle of 5-45° relative to the horizontal line. Specifically, it can be 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, or any two of these values ​​within a range, preferably 10-30°. This preferred embodiment allows the oil-water mixture to enter the column bottom below the baffle without causing oil-water separation, and prevents the upper oil phase from being carried upwards into the gas phase after separation. When the downward tilt angle is greater than the above-mentioned preferred range, the baffle tilt angle is larger. Under the condition of ensuring the same coverage, the longitudinal height of the baffle is larger, and the height of the straight pipe section of the absorber bottom needs to be increased accordingly, which will increase the equipment investment of the tower. Secondly, the larger the tilt angle of the baffle, the larger the area of ​​the baffle, and the longer the liquid residence time, which can easily cause oil and water to separate on the baffle, resulting in the exhaust gas not meeting the standards. When the downward tilt angle is less than the above-mentioned preferred range, there will be dead corners on the baffle, causing oil and water to separate. After the oil and water separate, the upper oil phase is carried upward into the gas phase.

[0020] In this invention, the baffle is divided into two types: with holes and without holes. Preferably, the baffle has holes. Using this preferred embodiment, the holes in the baffle can increase the coverage area of ​​the baffle, ensuring a suitable coverage area and reducing the amount of oil and gas volatilizing into the absorption tower, thus reducing the excessive exhaust gas content.

[0021] According to a preferred embodiment of the present invention, the baffle plate has no holes.

[0022] According to a preferred embodiment of the present invention, the lateral coverage area of ​​the baffle accounts for 50-90% of the cross-sectional area of ​​the absorption tower, preferably 60-80%.

[0023] According to a preferred embodiment of the present invention, the baffle is provided with openings evenly distributed, and the opening ratio of the openings is 1-10%.

[0024] According to a preferred embodiment of the present invention, the lateral coverage area of ​​the baffle accounts for 60-98% of the cross-sectional area of ​​the absorption tower, preferably 80-95%.

[0025] It should be noted that the lateral coverage area of ​​the baffle refers to the lateral projected area of ​​the baffle.

[0026] According to a preferred embodiment of the present invention, the baffle is disposed below the non-condensable gas inlet of the absorption tower.

[0027] According to a preferred embodiment of the present invention, the baffle is disposed on the same side as the non-condensable gas inlet of the absorption tower.

[0028] The present invention does not impose any particular limitation on the specific location of the baffle, and it can be appropriately adjusted according to actual conditions such as the amount of non-condensable gas to be treated and the amount of absorbent liquid used. According to a preferred embodiment of the present invention, the distance between the non-condensable gas inlet of the absorption tower and the baffle is 200-1000 mm, preferably 300-800 mm.

[0029] According to a preferred embodiment of the present invention, a gas distributor is further provided inside the absorption tower, located at the gas phase inlet, for uniformly dispersing the non-condensable gas. This preferred embodiment is more conducive to uniform gas distribution, preventing gas imbalances that could lead to large local exhaust gas volumes, incomplete treatment of oil exhaust gas, and excessive exhaust gas content.

[0030] This invention does not impose any particular limitation on the type of gas distributor; various gas distributors commonly used in the art can be used, as long as they can achieve the above-mentioned functions. These can be disc-type, branch-type, etc.

[0031] According to a preferred embodiment of the present invention, the gas distributor has evenly distributed upward-facing openings. This preferred embodiment helps prevent the gas from diffusing downwards or in all directions, and helps to entrain the oil phase in the liquid that cannot flow down the baffle in time.

[0032] The specific settings of the openings described in this invention (opening diameter, opening ratio, etc.) can be appropriately selected according to specific circumstances, and this invention does not have any particular limitations in this regard.

[0033] According to a preferred embodiment of the present invention, the gas distributor is disposed on the same side as the non-condensable gas inlet of the absorption tower.

[0034] The absorption tower described in this invention can be a single absorption tower or multiple towers connected in series, depending on the specific application.

[0035] According to a preferred embodiment of the present invention, the condensation device includes a water cooler and an aftercooler connected in series, for sequentially performing first condensation and second condensation on the oil-containing exhaust gas to obtain non-condensable gas.

[0036] According to a preferred embodiment of the present invention, the device further includes a condensate tank for collecting the condensate obtained from the first condensation and the second condensation.

[0037] In this invention, the condensate (water-cooled condensate and post-cooled condensate) obtained from the first condensation and the second condensation is sent to the downstream recovery unit.

[0038] According to a preferred embodiment of the present invention, the first liquid phase inlet of the condensate tank is connected to the liquid phase outlet of the water cooler.

[0039] According to a preferred embodiment of the present invention, the second liquid phase inlet of the condensate tank is connected to the liquid phase outlet of the aftercooler.

[0040] In this invention, an oil-water separator is connected to the bottom of the absorption tower, eliminating the accumulation of oil-water mixture in the tower bottom and effectively preventing the gas from carrying the upper oil phase after oil-water stratification. Furthermore, the oil-water mixture undergoes pre-separation in the oil-water separator, with circulating water containing a small amount of oil phase entering the separator for further separation, further reducing the volatile oil content in the circulating water before returning it to the absorption tower for reuse. As operating time increases, the oil content in the absorbent does not significantly increase, further reducing the amount of volatile oil carried by the gas to the absorption tower's gas phase outlet, achieving emission standards.

[0041] According to a preferred embodiment of the present invention, the apparatus further includes an oil-water separator for pre-separating the oil-water mixture to obtain a first oil phase and a first water phase.

[0042] In this invention, the outlet of the absorption tower and the inlet of the oil-water separator are connected by a pipeline.

[0043] According to a preferred embodiment of the present invention, the apparatus further includes an oil-water separator for separating the first aqueous phase to obtain a second oil phase and a second aqueous phase.

[0044] According to a preferred embodiment of the present invention, the aqueous phase outlet of the oil-water separator is connected to the absorbent inlet of the absorption tower, for returning the second aqueous phase to the absorption tower for recycling.

[0045] In this invention, both the first oil phase and the second oil phase are discharged outside the boundary.

[0046] According to a preferred embodiment of the present invention, the device further includes a water pump disposed between the oil-water separation tank and the oil-water separator, for conveying the first aqueous phase to the oil-water separator.

[0047] According to a preferred embodiment of the present invention, the apparatus further includes an absorbent circulation pump disposed between the oil-water separator and the absorption tower for conveying the second aqueous phase to the absorption tower.

[0048] According to a specific embodiment of the present invention, it can be referred to Figure 1 The oily exhaust gas 1 is sent to water cooler I for first condensation to obtain water-cooled gas phase 2 and water-cooled condensate 4; the water-cooled gas phase 2 is sent to aftercooler II for second condensation to obtain non-condensable gas 3 and aftercooled condensate 5; the water-cooled condensate 4 and aftercooled condensate 5 are both stored in condensate tank III and then sent to the downstream recovery unit. The non-condensable gas 3 is sent to the absorption tower IV, dispersed by the gas distributor IV-1, and then comes into contact with the absorbent liquid to obtain exhaust gas 11 and oil-water mixture 6. Exhaust gas 11 is discharged upwards, and oil-water mixture is discharged downwards through baffle IV-2. There is no stagnant liquid on the baffle, and then it enters the oil-water separator V through the pipeline for oil-water pre-separation to obtain the first aqueous phase 7 and the first oil phase 9. The first aqueous phase 7 is sent to the oil-water separator VIII by the water pump VI for oil-water separation to obtain the second aqueous phase 8 and the second oil phase 10. The second aqueous phase 8 is returned to the absorption tower IV for recycling by the absorbent liquid circulation pump VII; the first oil phase 9 and the second oil phase 10 are sent outside the boundary.

[0049] A second aspect of the present invention provides a method for operating the processing apparatus described in the first aspect, the method comprising the following steps: (1) The oily exhaust gas is condensed to obtain non-condensable gas; (2) The oil in the non-condensable gas is absorbed by an absorbent to obtain an exhaust gas and an oil-water mixture; wherein the concentration of VOC in the exhaust gas is not higher than 0.1 mg / L.

[0050] The method described in this invention can treat oily exhaust gases containing different concentrations of oil. According to a preferred embodiment of this invention, the oil concentration in the oily exhaust gas is 100-1000 mg / L.

[0051] According to a preferred embodiment of the present invention, the oil in the oily exhaust gas includes at least one of silicone oil, liquid paraffin, ester oil, and fluorinated oil.

[0052] The present invention does not specifically limit the ester oil, and it can be any kind of ester oil commonly found in the art.

[0053] The oily exhaust gas described in this invention can be any oily exhaust gas obtained in various ways in the art, and this invention does not have any particular limitation on it.

[0054] In step (1) of this invention, the oily exhaust gas is condensed to remove most of the oily substances from the exhaust gas. According to a preferred embodiment of this invention, step (1) ensures that the oil removal rate is not less than 50%.

[0055] According to a preferred embodiment of the present invention, the condensation includes a first condensation and a second condensation.

[0056] According to a preferred embodiment of the present invention, the condensation temperature of the first condensation is 40-60°C, specifically 40°C, 45°C, 50°C, 55°C, 60°C, and any two of these values ​​forming a range.

[0057] According to a preferred embodiment of the present invention, the condensation temperature of the second condensation is -10 to 20°C, specifically -10°C, -5°C, 0, 5°C, 10°C, 15°C, 20°C, and any two of these values ​​forming a range.

[0058] According to a preferred embodiment of the present invention, the mass flow ratio of the absorbent to the noncondensable gas is 2-10:1.

[0059] The present invention allows for a wide range of choices regarding the type of absorbent, which can be conventional choices in the art. According to a preferred embodiment of the present invention, the absorbent is an aqueous solution of water or an acid.

[0060] The present invention does not particularly limit the aqueous solution of the acid, and any conventional choice in the art can be used, such as aqueous solutions of hydrochloric acid, sulfuric acid, nitric acid, or other inorganic salts.

[0061] In this invention, the outlet of the absorber tower and the inlet of the oil-water separator are connected by a pipeline. According to a preferred embodiment of the invention, the flow velocity of the oil-water mixture in the pipeline is no higher than 0.5 m / s. This preferred embodiment prevents liquid accumulation at the bottom of the absorber tower, thus preventing oil-water separation and avoiding the upper oil phase being carried upwards into the gas phase after separation.

[0062] The present invention will be described in detail below through embodiments.

[0063] The VOC concentration in exhaust gas was measured by gas chromatography. The oil content in the gas was determined by gas chromatography.

[0064] Example 1 Devices such as Figure 1 As shown.

[0065] 800m³ of tail gas containing 1,1,3,3-tetramethylsilazane 3 The concentration of 1,1,3,3-tetramethylsilazane is 600 mg / L, and the remaining components are nitrogen. The oily tail gas is cooled to 40°C by a water cooler and then cooled to 0°C by an aftercooler to obtain non-condensable gas, in which the concentration of 1,1,3,3-tetramethylsilazane is reduced to 50 mg / L.

[0066] The absorption tower is a water absorption tower with a water-to-noncondensable gas mass flow ratio of 6:1. The noncondensable gas enters the gas distributor with an upward-facing opening on the same side from the gas phase inlet of the absorption tower. A horizontal baffle is installed below the gas inlet on the same side of the absorption tower, with a distance of 500 mm between the gas phase inlet and the baffle. The baffle is inclined downward at 15°, and its horizontal coverage area accounts for 90% of the cross-sectional area of ​​the absorption tower. The baffle has evenly distributed openings with an opening rate of 5%. There is no stagnant liquid on the baffle.

[0067] The outlet of the absorber tower and the inlet of the oil-water separator are connected by a pipeline, and the flow velocity of the oil-water mixture in the pipeline is 0.3 m / s. After the oil-water mixture is separated by the oil-water separator, the resulting aqueous phase is recycled back to the absorber tower for reuse.

[0068] The VOC concentration in the exhaust gas after treatment is <0.1mg / L, achieving the emission standard.

[0069] Example 2 Devices such as Figure 1 As shown.

[0070] 800m³ of tail gas containing 1,1,3,3-tetramethylsilazane 3 The concentration of 1,1,3,3-tetramethylsilazane is 600 mg / L, and the remaining components are nitrogen. The oily tail gas is cooled to 40°C by a water cooler and then cooled to 20°C by an aftercooler to obtain non-condensable gas, in which the concentration of 1,1,3,3-tetramethylsilazane is reduced to 80 mg / L.

[0071] The absorption tower is a water absorption tower, with a mass flow ratio of water to non-condensable gas of 6:1. The non-condensable gas enters the gas distributor with upward openings on the same side from the gas phase inlet of the absorption tower. A horizontal baffle is installed below the gas inlet on the same side of the absorption tower, with a distance of 500 mm between the gas phase inlet and the baffle. The baffle is inclined downward at 25°, and the horizontal coverage area of ​​the baffle accounts for 85% of the cross-sectional area of ​​the absorption tower. The baffle has evenly distributed openings with an opening rate of 4%. There is no stagnant liquid on the baffle.

[0072] The outlet of the absorber tower and the inlet of the oil-water separator are connected by a pipeline, with the flow velocity of the oil-water mixture in the pipeline being 0.3 m / s. After the oil-water mixture is separated by the oil-water separator, the resulting aqueous phase is recycled back to the absorber tower for reuse.

[0073] The VOC concentration in the exhaust gas after treatment is <0.1mg / L, achieving the emission standard.

[0074] Example 3 The operating conditions were the same as in Example 1, except that the gas was directly fed into the absorption tower after being cooled to 40°C by a water cooler. The concentration of 1,1,3,3-tetramethylsilazane in the gas phase after water cooling was 200 mg / L.

[0075] The VOC concentration in the exhaust gas after treatment is <0.1mg / L, achieving the emission standard.

[0076] However, due to the reduced recovery of 1,1,3,3-tetramethylsilazane in the aforementioned condensation step, the amount of absorbent used has increased significantly, resulting in a corresponding increase in wastewater and increased environmental pressure. Secondly, the reduction in oil condensation leads to a decrease in oil recovery and an increase in raw material consumption.

[0077] Comparative Example 1 The operating conditions are the same as in Example 1. The difference is that no horizontal baffle is installed in the absorption tower, and the oil-water mixture is stored in the bottom of the absorption tower. No oil-water separation tank or oil-water separator is installed. A pump is installed in the bottom of the tower to collect the water phase separated from the oil and water and circulate it to the absorption tower. The upper oil phase is collected.

[0078] After non-condensable gas is treated in the absorption tower, the VOC concentration in the exhaust gas gradually increases from below 0.1 mg / L initially. After 12 hours of absorption, the VOC concentration in the exhaust gas reaches 12 mg / L, which is below the standard. This is because the absorber contains an oil-water mixture, causing phase separation within the tower. The upper oil phase is carried away during gas purging, resulting in a higher oil concentration in the exhaust gas than in the non-condensable gas. Furthermore, the lack of an oil-water separator leads to a gradual increase in the oil content in the circulating absorption liquid, causing the exhaust gas concentration to severely exceed the standard.

[0079] Comparative Example 2 The operating conditions are the same as in Example 1, except that no horizontal baffles are installed inside the absorption tower.

[0080] After the non-condensable gas is treated in the absorption tower, the oil phase concentration in the exhaust gas gradually increases. Compared to Comparative Example 2, the absorbent liquid enters the oil-water separator directly without being separated by baffles. There is no liquid in the tower bottom, but the gas phase space is increased, and volatile oil rises into the absorption tower bed. As the operating time is extended to 72 hours, a certain amount of oil phase still accumulates in the absorption tower bottom, causing the VOC concentration in the exhaust gas to exceed 0.1 mg / L and fail to meet the standard.

[0081] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A device for treating oily exhaust gas, characterized in that, The apparatus includes: a condensation device and an absorption tower; The condensation equipment is used to condense oily exhaust gas to obtain non-condensable gas; The absorption tower is used to absorb the oil in the non-condensable gas using an absorbent liquid, to obtain exhaust gas and an oil-water mixture; The absorption tower is equipped with a baffle that is tilted downwards relative to the horizontal line at an angle of 5-45°.

2. The processing apparatus according to claim 1, wherein, The baffle is tilted downward at an angle of 10-30° relative to the horizontal line; Preferably, the baffle is located below the non-condensable gas inlet of the absorption tower; Preferably, the baffle is located on the same side as the non-condensable gas inlet of the absorption tower; Preferably, the distance between the non-condensable gas inlet of the absorption tower and the baffle is 200-1000mm, and more preferably 300-800mm.

3. The processing apparatus according to claim 1 or 2, wherein, The baffle plate has no holes. Preferably, the lateral coverage area of ​​the baffle accounts for 50-90% of the cross-sectional area of ​​the absorption tower, and more preferably 60-80%.

4. The processing apparatus according to claim 1 or 2, wherein, The baffle is evenly distributed with openings, and the opening ratio of the openings is 1-10%. Preferably, the lateral coverage area of ​​the baffle accounts for 70-98% of the cross-sectional area of ​​the absorption tower, and more preferably 80-95%.

5. The processing apparatus according to any one of claims 1-4, wherein, The absorption tower is also equipped with a gas distributor to uniformly disperse the non-condensable gas. Preferably, the gas distributor has evenly distributed upward-facing openings; Preferably, the gas distributor is located on the same side as the non-condensable gas inlet of the absorption tower.

6. The processing apparatus according to any one of claims 1-5, wherein, The condensation equipment includes a water cooler and an aftercooler connected in series, used to perform first condensation and second condensation on the oily exhaust gas in sequence to obtain non-condensable gas. Preferably, the apparatus further includes an oil-water separator for pre-separating the oil-water mixture to obtain a first oil phase and a first water phase; Preferably, the device further includes an oil-water separator for separating the first aqueous phase to obtain a second oil phase and a second aqueous phase; Preferably, the aqueous phase outlet of the oil-water separator is connected to the absorbent inlet of the absorption tower, so as to return the second aqueous phase to the absorption tower for recycling.

7. A method of operating the processing apparatus according to any one of claims 1-6, the method comprising the following steps: (1) The oily exhaust gas is condensed to obtain non-condensable gas; (2) The oil in the non-condensable gas is absorbed by an absorbent to obtain an exhaust gas and an oil-water mixture; wherein the concentration of VOC in the exhaust gas is not higher than 0.1 mg / L.

8. The method according to claim 7, wherein, The oil concentration in the oily exhaust gas is 100-1000 mg / L; Preferably, the oil in the oily exhaust gas includes at least one of silicone oil, liquid paraffin, ester oil, and fluorinated oil.

9. The method according to claim 7, wherein, Step (1) ensures that the oil removal rate is not less than 50%; Preferably, the condensation includes a first condensation and a second condensation; Preferably, the condensation temperature of the first condenser is 40-60℃; Preferably, the condensation temperature of the second condenser is -10 to 20°C.

10. The method according to any one of claims 7-9, wherein, The mass flow ratio of the absorbent liquid to the non-condensable gas is 2-10:1; Preferably, the absorbent is an aqueous solution of water or an acid.

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