VOC flue gas purification device and purification method thereof

Abstract

The application relates to the technical field of flue gas purification, in particular to a VOC flue gas purification device and a purification method thereof, wherein the VOC flue gas purification device comprises a first treatment unit, the gas inlet of the first treatment unit is connected with a waste gas source through a waste gas input pipe, a partition plate and a liquid seal structure are arranged in the first treatment unit, and the first treatment unit is used for carrying out primary condensation absorption on waste gas; a flue gas washing unit comprises a flue gas washing tower, the side of the flue gas washing tower is connected with the gas phase outlet of the first treatment unit through a first waste gas pipe, the bottom of the flue gas washing tower is provided with a circulating liquid outlet, the top of the flue gas washing tower is provided with a spraying pipe, and the spraying pipe extends to the top end in the flue gas washing tower; and a post-treatment unit is arranged. The first treatment unit and the washing oil mixed absorbent are adopted to efficiently remove naphthalene and heavy organic matters in waste gas, the possibility of pipe furnace nozzle blockage is reduced, the blockage problem caused by aging of traditional PP fillers is reduced by selecting stainless steel Paul ring fillers, and the service life of the equipment is prolonged.

Description

Technical Field

[0001] This application relates to the field of flue gas purification technology, and in particular to a VOC flue gas purification device and purification method thereof. Background Technology

[0002] VOC emissions are widely generated in industries such as coal tar processing, petrochemicals, and paint production. Especially in the coal tar processing and carbon black production industries, the emitted VOCs are often characterized by complex composition, high naphthalene content, corrosiveness, and flammability and explosiveness, posing a serious threat to the environment and human health. Existing technologies for treating such emissions mostly suffer from the following problems: Inadequate intake treatment leads to equipment failure: exhaust gas often contains a large amount of naphthalene and tar and other sticky substances. If the front-end condensation and absorption are not thorough, it is very easy to cause blockage of subsequent pipes and burner nozzles, affecting the normal operation of the incineration equipment. In addition, incomplete combustion can also easily produce secondary pollutants such as dioxins. Significant safety hazards: In traditional processes, the oxygen content is often not effectively controlled when waste gas is introduced into the incineration system. When the waste gas concentration fluctuates to the explosion limit, flash explosions and backfires are very likely to occur in tubular furnaces or pipelines. Moreover, most old systems lack effective flame arresting facilities, resulting in poor safety and a high risk of production accidents.

[0003] Furthermore, in the transmission process, it is difficult to balance efficiency and cost when using only a single absorption or combustion process. For example, water spraying alone is not effective in absorbing hydrophobic organic compounds (such as naphthalene), while full incineration consumes a lot of energy and has a high treatment cost. Summary of the Invention

[0004] This application provides a VOC flue gas purification device and purification method to solve the problems of insufficient pretreatment in existing technologies, which can easily lead to equipment blockage and failure, as well as low efficiency and significant safety hazards.

[0005] This application provides a VOC flue gas purification device, comprising: The first treatment unit has an air inlet connected to the exhaust gas source via an exhaust gas input pipe. It is equipped with a partition plate and a liquid seal structure inside for primary condensation and absorption of the exhaust gas. The flue gas scrubbing unit includes a flue gas scrubbing tower. The side of the flue gas scrubbing tower is connected to the gas phase outlet of the primary treatment unit through a first waste gas pipe. The bottom of the flue gas scrubbing tower is provided with a circulating liquid outlet, and the top is provided with a spray pipe that extends to the top of the interior of the flue gas scrubbing tower.

[0006] The post-treatment unit is connected to the gas phase outlet of the flue gas scrubbing unit and is used to incinerate the waste gas after the secondary deep absorption of the flue gas scrubbing unit.

[0007] Preferably, the first processing unit includes several breathing slots arranged in parallel; The breathing tank contains a washing oil absorbent. The partition plate is horizontally arranged in the upper part of the breathing tank to divide the breathing tank into upper and lower layers. The liquid seal structure is arranged at the air inlet to prevent gas short circuit.

[0008] Preferably, the flue gas scrubbing unit further includes a circulating pump, the inlet of which is connected to the circulating liquid outlet at the bottom of the flue gas scrubbing tower, and the outlet is connected to a cooler, the outlet end of which is connected to the spray pipe.

[0009] Preferably, the circulating fluid is a self-produced washing oil absorbent, which can reduce costs and enable reuse; The temperature of the circulating liquid in the flue gas scrubbing tower is controlled between 35℃ and 45℃.

[0010] Preferably, the flue gas scrubbing tower is filled with Pall ring packing, and the Pall ring packing is made of stainless steel; The specific surface area of ​​the Pall ring packing is ≥150 m². 2 / m 3 Porosity ≥ 90%.

[0011] Preferably, the post-processing unit includes: The fan unit has its inlet connected to the exhaust port located at the top of the flue gas scrubbing tower; The water seal tank is connected to the outlet end of the fan device through the second exhaust gas pipe, and cools and neutralizes the exhaust gas after it has been washed by the flue gas scrubbing unit. The demister has its inlet connected to the outlet of the water seal tank via a third exhaust gas pipe. It is used to dehumidify the exhaust gas after it has been treated by the water seal tank. The dehumidified exhaust gas is then transported to the tubular furnace for incineration via the tubular furnace conveying pipeline.

[0012] Preferably, the water seal tank contains an alkaline absorbent liquid to neutralize the acidic components in the exhaust gas, and an oil separator is provided at its bottom. A water seal tank circulation pump is also provided between the water seal tank and the oil separator.

[0013] Preferably, it also includes a nitrogen generator, the outlet of which is connected to the waste gas source storage tank via a breather valve, for filling the waste gas source storage tank with nitrogen to form a micro-positive pressure protection and reduce the oxygen content of the waste gas system.

[0014] This application also provides a purification method based on the VOC flue gas purification device described in any one of the above claims, comprising: Step S1: The VOC flue gas is introduced into the first treatment unit, and after being condensed by the washing oil seal, some of the naphthalene and high-boiling-point substances are removed. Step S2: The pre-treated flue gas is introduced into the flue gas scrubbing tower and comes into countercurrent contact with the circulating sprayed oil-water mixed absorbent to absorb the VOC components in the flue gas. Step S3: The washed flue gas is sent into the water seal tank by a fan device to neutralize the acidic gases therein. Step S4: After the neutralized flue gas is dehumidified by a demister, it is sent into a tubular furnace for incineration. Step S5: The clean gas after incineration is discharged at high altitude after passing the standard test.

[0015] Preferably, in step S2, when the moisture content in the circulating absorbent is ≥10% or the naphthalene content is ≥8%, the absorbent is replaced, and the replaced absorbent is returned to the raw material tank for recycling.

[0016] The beneficial effects of this application are as follows: The VOC flue gas purification device and purification method of this application use a first treatment unit and a washing oil mixed absorbent to efficiently remove naphthalene and heavy organic matter in the waste gas, reduce the possibility of nozzle blockage in the tubular furnace, and at the same time, by using stainless steel Pall ring packing, reduce the blockage problem caused by the aging of traditional PP packing and extend the equipment life.

[0017] Furthermore, by employing a wash oil liquid seal structure in the first treatment unit, VOC flue gas is initially condensed while removing naphthalene and high-boiling-point substances to prevent blockage of subsequent equipment. By using a wash oil absorbent in the flue gas scrubbing tower and controlling the temperature of the wash oil absorbent in the circulation loop using a cooler, the removal efficiency of VOCs is improved. At the same time, a nitrogen generator provides nitrogen seal protection at the exhaust gas source to reduce the oxygen content of the exhaust gas, eliminate the risk of explosion at the source, and extend the system's operating cycle. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the VOC flue gas purification device provided in the embodiments of this application; Figure 2 This is a schematic flowchart of the purification method provided in the embodiments of this application.

[0020] Figure label: 1. Flue gas scrubber; 2. First exhaust gas pipe; 3. Connecting branch pipe; 4. Breathing tank; 5. Air inlet; 6. Air outlet; 7. Circulating pump; 8. Cooler; 9. Spray pipe; 10. Exhaust port; 11. Fan unit; 12. Second exhaust gas pipe; 13. Water seal tank circulating pump; 14. Water seal tank; 15. Third exhaust gas pipe; 16. Demister; 17. Oil separator. Detailed Implementation

[0021] The technical solutions of this application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] The following is combined Figure 1 and Figure 2 This application describes the VOC flue gas purification device and purification method provided in the embodiments.

[0023] Reference Figure 1 As shown, the VOC flue gas purification device provided in this application mainly consists of three parts: a pretreatment unit, a flue gas scrubbing unit, and a posttreatment unit, wherein: The primary treatment unit is connected to the main exhaust pipe of the production workshop and other exhaust gas sources via an exhaust gas inlet pipe. In this embodiment, the primary treatment unit specifically consists of three parallel breathing tanks 4. The gas phase outlet of the three parallel breathing tanks 4 is connected to the first exhaust gas pipe 2 via a connecting branch pipe 3. The breathing tanks 4 are filled with washing oil for preliminary condensation and absorption of VOC flue gas and naphthalene compounds. Specifically, the top of the breathing tank 4 is provided with an air inlet 5 connected to the exhaust gas inlet pipe, and the upper part of the breathing tank 4 is also provided with a partition plate 6 for dividing the entire breathing tank or the upper part into upper and lower or left and right sides. The breathing tank 4, i.e., the washing oil sealing tank, is filled with washing oil absorbent. Specifically, when the partition plate 6 is a horizontally arranged partition plate, it can be set at about 2 / 5 of the position inside the breathing tank 4. The edge of the plate is sealed to the inner wall of the breathing tank 4. The upper and lower sides of the breathing tank 4 are filled with washing oil absorbent. Moreover, the partition plate is provided with an overflow port for connecting the upper and lower sides of the breathing tank 4. A hollow cylindrical body is also vertically arranged around the overflow port. The height of the cylindrical body is higher than the liquid level of the washing oil absorbent. The end of the air inlet 5 is inserted below the liquid level of the washing oil absorbent and located above the horizontally arranged partition plate to form a liquid seal structure. A washing oil circulation pump is also provided between the upper and lower sides of the breathing tank 4 for pumping the low-temperature washing oil absorbent from the lower side to the upper side for replenishment. A filter screen can also be provided inside the cylindrical body to filter the circulating washing oil absorbent. During operation, the high-temperature washing oil absorbent located on the upper side of the breathing tank 4 is cooled down by overflowing from the top of the cylindrical body into the low-temperature washing oil absorbent on the lower side of the breathing tank 4 under the lifting of flue gas and the pumping of the washing oil circulation pump. The low-temperature washing oil absorbent on the lower side is then lifted to the top of the partition plate 6 by the pumping of the circulation pump to replenish the washing oil absorbent on the upper side, forming a pumping circulation.

[0024] In another specific embodiment, when the partition plate 6 is a vertically arranged vertical partition plate, it divides the upper area of ​​the breathing groove 4 into left and right areas. Both left and right areas are filled with washing oil absorbent, and the liquid level of the washing oil absorbent must be above the lower edge of the vertically arranged partition plate 6. The end of the air inlet 5 extends from one side of the breathing groove 4 to a position below the lower edge of the partition plate 6, so that a liquid seal structure is formed at the air inlet 5. This ensures that the incoming exhaust gas must pass through the washing oil layer for gas-liquid contact before entering the space on this side or the other side of the partition plate. This stage of treatment can condense and remove most of the high-boiling-point naphthalene substances and tar in the exhaust gas, preventing subsequent pipeline blockage. In addition, the top of the partition plate 6 is also provided with a gas equalization hole for connecting the top spaces on both sides. The other side of the breathing tank 4 is also provided with a washing oil absorbent circulation pump. The output end of the circulation pump extends from the gas equalization hole to the side of the air inlet 5, lifting the high-temperature washing oil absorbent to the top of the breathing tank before circulation pumping. While appropriately cooling the washing oil absorbent, it also increases the contact distance between the flue gas and the washing oil absorbent, improving its absorption effect.

[0025] In some specific embodiments, the flue gas scrubbing unit includes a flue gas scrubbing tower 1, the side of which is connected to the gas phase outlet of the breathing tank 4 via a first exhaust gas pipe 2. The exhaust gas, after being condensed and absorbed by the primary treatment unit, enters the interior of the flue gas scrubbing tower 1 through the first exhaust gas pipe 2 and the gas inlet 6. The interior of the flue gas scrubbing tower 1 is filled with Pall ring packing. Compared to traditional PP packing, this embodiment selects stainless steel or other corrosion-resistant metals as the Pall ring packing material, giving it the characteristics of high temperature resistance, corrosion resistance, and high mechanical strength. Furthermore, the specific surface area of ​​the Pall ring packing is ≥150 m². 2 / m3 With a porosity of ≥90%, it increases the gas-liquid contact area, improves mass transfer efficiency, and is not easily blocked by viscous substances.

[0026] In practical implementation, for example, conventional metal / PP Pall rings with specifications of Φ16mm and Φ25mm can stably meet the requirement of a specific surface area ≥150 m². 2 / m 3 The specific requirements vary, and when using Φ38mm and above specifications, customization is required to meet its high specific surface area structure. For a porosity of ≥90%, most commercially available metal / PP materials can meet this requirement, while ceramic materials generally have a porosity of less than 90%, so they are not selected. Therefore, after comprehensive consideration, Φ25mm stainless steel Pall rings can be selected as the actual application object in this application embodiment.

[0027] By employing a primary treatment unit and a washing oil mixed absorbent, naphthalene and heavy organic matter in the waste gas are efficiently removed, reducing the possibility of nozzle clogging in the tubular furnace. At the same time, by selecting stainless steel Pall ring packing, the clogging problem caused by the aging of traditional PP packing is reduced, extending the equipment life.

[0028] The flue gas scrubbing unit is equipped with a circulating spray system. Specifically, the bottom of the flue gas scrubbing tower 1 is provided with a circulating liquid outlet. The inlet of the circulating pump 7 is connected to the circulating liquid outlet. The circulating pump 7 draws out the circulating liquid. The outlet of the circulating pump 7 is connected to a cooler 8. The outlet of the cooler 8 is connected to a spray pipe 9 that extends to the top of the flue gas scrubbing tower 1, forming a circulating cooling loop.

[0029] In this embodiment, the circulating fluid uses wash oil absorbent. Wash oil has excellent affinity for hydrophobic organic compounds (such as naphthalene and benzene) and reduces costs. The main function of wash oil is to dissolve and absorb VOCs, reduce the viscosity of the absorbent, improve its fluidity, and absorb some water-soluble VOCs. It is also cost-effective and facilitates subsequent regeneration.

[0030] Meanwhile, in order to prevent the washing oil from becoming too viscous or volatile, the spraying temperature of the circulating liquid in the flue gas scrubbing tower 1 can be controlled between 35°C and 45°C, preferably 40°C, by the cooler 8. Within this temperature range, the washing oil has a high absorption efficiency for naphthalene and is not prone to crystallization, so as to maintain the best absorption effect.

[0031] The post-treatment unit includes a fan unit 11, a water seal tank 14, a demister 16, and a tubular furnace. The inlet of the fan unit 11 is connected to the exhaust port 10 at the top of the flue gas scrubbing tower 1, and its outlet is connected to the water seal tank 14 via a second waste gas pipe 12. The waste gas purified by the scrubbing tower is discharged from the exhaust port 10 at the top of the tower and enters the post-treatment unit. Specifically: First, the exhaust gas enters the second exhaust gas pipe 12 through the fan device 11. The fan device 11 is preferably a variable frequency fan, whose outlet pressure is interlocked with the inlet pipe pressure to stabilize the system air volume and pressure and prevent the risk of backfire caused by pressure fluctuations. The water seal tank 14 is filled with alkaline absorbent liquid (such as dilute sodium hydroxide solution) to neutralize the residual acidic components (such as H2S, SO2, etc.) in the exhaust gas, and at the same time plays a role in physical water seal flame arrest.

[0032] In this embodiment, an oil separator 17 is also provided at the bottom or side of the water seal tank 14. The two are connected by a water seal tank circulation pump 13. Since the circulating liquid contains washing oil components, a small amount of oily substances carried out with the gas will accumulate in the water seal tank 14. At this time, the water seal tank circulation pump 13 located between the two can transport the oil-containing absorbent liquid in the water seal tank 14 to the oil separator 17 for oil-water separation, or use it to return the separated clear liquid to the water seal tank for continued use, keeping the liquid level in the water seal tank constant. The separated oil phase can be recycled, while the clear liquid is returned to the water seal tank 14 for continued use, so as to keep the liquid level in the water seal tank constant, forming a closed loop circulation and ensuring the water seal effect. In addition, the water seal tank 14 can also be connected to the alkaline absorbent liquid replenishment tank by setting a separate input pump to replenish the alkaline absorbent liquid in it.

[0033] The exhaust gas, after being treated by the water seal tank 14, enters the demister 16 through the third exhaust gas pipe 15. The demister 16 removes mist droplets and moisture from the gas to prevent moisture from entering the subsequent incineration system and affecting the furnace temperature. The dried exhaust gas finally enters the tubular furnace for incineration. In this embodiment, the tubular furnace is equipped with an industrial burner, preferably a Maxon industrial burner from the United States, which uses coal gas as fuel and has a continuous proportional adjustment range of 30:1 to adapt to fluctuations in exhaust gas concentration. The burner is equipped with a UV flame detector and an interlock shut-off valve for automatically cutting off fuel and exhaust gas when the flame is extinguished. During normal combustion, the UV detector displays a flame signal. If the flame is accidentally extinguished, the system immediately and automatically cuts off the coal gas and exhaust gas supply and opens the venting valve to ensure safety.

[0034] In some specific embodiments, to address the explosion risk caused by excessive oxygen content, the device is also equipped with a nitrogen protection system, which includes a nitrogen generator. The outlet of the nitrogen generator is connected to the waste gas source storage tank through a breather valve, so as to fill the storage tank with nitrogen at the source of waste gas generation to form a slight positive pressure protection, reduce the evaporation of organic waste gas, and reduce the oxygen content of the waste gas entering the subsequent system, so that it is always kept below the safe explosion limit, thus eliminating the explosion risk from the source.

[0035] By employing a wash oil liquid seal structure in the first treatment unit, VOC flue gas is initially condensed while removing naphthalene and high-boiling-point substances to prevent blockage of subsequent equipment. By using a wash oil-water mixed absorbent in the flue gas scrubbing tower 1 and controlling the temperature of the mixed absorbent in the circulation loop in conjunction with the cooler 8, the removal efficiency of VOCs is improved. At the same time, a nitrogen generator provides nitrogen seal protection at the exhaust gas source to reduce the oxygen content of the exhaust gas, eliminate the risk of explosion from the source, and extend the system's operating cycle.

[0036] In some specific embodiments, such as Figure 2 As shown, this application also provides a purification method for a VOC flue gas purification device based on any of the above claims, mainly comprising: Step S1: The VOC flue gas is introduced into the first treatment unit, and after being condensed by the washing oil seal, some of the naphthalene and high-boiling-point substances are removed. Step S2: The pre-treated flue gas is introduced into the flue gas scrubbing tower 1 and comes into countercurrent contact with the circulating sprayed oil-water mixed absorbent to absorb the VOC components in the flue gas. Step S3: The washed flue gas is sent into the water seal tank 14 through the fan device 11 to neutralize the acidic gas therein; Step S4: After the neutralized flue gas is dehumidified by the demister 16, it is sent into the tubular furnace for incineration. Step S5: The clean gas after incineration is discharged at high altitude after passing the standard test.

[0037] Specifically, firstly, VOC flue gas is introduced into the breathing tank 4 through the air inlet 5. After passing through the liquid seal layer formed by the partition plate and the liquid seal mechanism, the flue gas comes into contact with the low-temperature washing oil. The naphthalene and high-boiling-point viscous substances in the oil are absorbed and condensed by the washing oil, and some large particulate impurities settle down. The gas after preliminary purification is discharged from the gas phase outlet, completing the first-stage condensation absorption.

[0038] Subsequently, the pre-treated flue gas enters the bottom of the flue gas scrubbing tower 1 from the side through the first waste gas pipe 2 and flows upward. Simultaneously, the circulating pump 7 extracts the wash oil-water mixed absorbent from the bottom of the tower, cools it through the cooler 8, and then sprays it downward through the spray pipe 9, contacting the flue gas counter-currently to absorb VOC components, performing secondary deep absorption. The absorbent temperature is controlled at approximately 40℃, and fresh wash oil and water are periodically replenished through online monitoring to maintain the mixing ratio. When the moisture content in the circulating absorbent is ≥10% or the naphthalene content is ≥8%, it is replaced, and the replaced absorbent is returned to the raw material tank for recycling.

[0039] Specifically, the replacement steps can be described as follows: Monitoring process: Samples are taken daily to test the moisture content and naphthalene content of the circulating fluid. The replacement procedure is initiated when two consecutive test results reach or exceed the threshold.

[0040] Replacement steps: Stop adding new wash oil absorbent, close the circulation pump 7 and the flue gas inlet valve, open the absorbent to be replaced in the tower through the bottom drain port, close the outlet valve of the circulation pump 7 to the tower, open the absorbent to feed material tank valve, and send all the absorbent to the feed material tank. Replace the absorbent with fresh wash oil and flush the packing layer. The flushing volume should be 1.2-1.5 times the volume of the packing in the tower to remove residual absorbent with high moisture and high naphthalene content. After rinsing, the absorbent is sent into the raw material tank, and then the circulation pump is started to inject new absorbent to the normal liquid level in the tower (usually 1 / 3 to 1 / 2 of the tower height). Reopen the flue gas inlet valve and gradually adjust the flow rate to normal operating conditions. At the same time, monitor the VOC concentration at the outlet to ensure that the purification efficiency meets the standards.

[0041] The collected absorbent to be replaced is sent to the raw material tank, and then the wash oil and naphthalene are separated and recovered through processes such as distillation. The regenerated wash oil can be returned to the system for recycling.

[0042] After secondary absorption, the flue gas is sent into the water seal tank 14 by the fan device 11, where it comes into contact with the alkaline absorbent liquid to neutralize the acidic gas and cool the flue gas again. At the same time, the water seal structure also plays a role in flame arrest, reducing the possibility of backfire and explosion. The oil phase separated in the tank enters the oil separator 17 for separation and recovery.

[0043] After neutralization, the flue gas is dehumidified by demister 16 and then sent to a tubular furnace for combustion. The combustion temperature is controlled above 550℃, at which temperature, organic matter is completely oxidized and decomposed into CO2 and H2O. The burner automatically adjusts the gas flow according to the exhaust gas concentration, and a UV flame detector monitors the flame status in real time. If the flame goes out, the fuel and exhaust gas are immediately cut off, and the vent valve is opened to ensure combustion safety.

[0044] After the high-temperature flue gas from incineration undergoes waste heat recovery and gas detection, it is then discharged into the atmosphere through a chimney, completing the purification process.

[0045] Specifically, the VOC flue gas purification device provided in this application embodiment can be used to perform the above-mentioned purification method to achieve the desired technical effect, which will not be elaborated further here.

[0046] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application 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 this application.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0048] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0049] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0050] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A VOC flue gas purification device, characterized in that, include: The first treatment unit has an air inlet (5) connected to the exhaust gas source through an exhaust gas input pipe. It is equipped with a partition plate and a liquid seal structure for primary condensation and absorption of exhaust gas. The flue gas scrubbing unit includes a flue gas scrubbing tower (1), the side of which is connected to the gas phase outlet of the first treatment unit through a first waste gas pipe (2). The bottom of the flue gas scrubbing tower (1) is provided with a circulating liquid outlet, and the top is provided with a spray pipe (9). The spray pipe (9) extends to the top of the inside of the flue gas scrubbing tower (1). The post-treatment unit is connected to the gas phase outlet of the flue gas scrubbing unit and is used to incinerate the waste gas after the secondary deep absorption of the flue gas scrubbing unit.

2. The VOC flue gas purification device according to claim 1, characterized in that, The first processing unit includes several breathing tanks (4) arranged in parallel. The breathing tank (4) contains a washing oil absorbent. The partition plate is arranged horizontally / vertically in the upper part of the breathing tank (4) to divide the entire breathing tank (4) into two layers: upper and lower / left and right. The liquid seal structure is set at the air inlet (5) to prevent gas short circuit.

3. The VOC flue gas purification device according to claim 2, characterized in that, The flue gas scrubbing unit also includes a circulating pump (7), whose inlet is connected to the circulating liquid outlet at the bottom of the flue gas scrubbing tower (1), and whose outlet is connected to a cooler (8), the outlet end of which is connected to the spray pipe (9).

4. The VOC flue gas purification device according to claim 3, characterized in that, The circulating liquid is a self-produced washing oil absorbent, which can reduce costs and can be reused; the temperature of the circulating liquid in the flue gas scrubbing tower (1) is controlled between 35℃ and 45℃.

5. The VOC flue gas purification device according to claim 1, characterized in that, The flue gas scrubbing tower (1) is filled with Pall ring packing, and the Pall ring packing is made of stainless steel. The specific surface area of ​​the Pall ring packing is ≥150 m². 2 / m 3 Porosity ≥ 90%.

6. The VOC flue gas purification device according to claim 1, characterized in that, The post-processing unit includes: The inlet of the fan unit (11) is connected to the exhaust port (10) located at the top of the flue gas scrubbing tower (1); The water seal tank (14) is connected to the outlet end of the fan device (11) through the second exhaust gas pipe (12) to cool and neutralize the exhaust gas after it has been washed by the flue gas scrubbing unit; The demister has its inlet connected to the outlet of the water seal tank (14) via the third exhaust gas pipe (15) for dehumidifying the exhaust gas after it has been treated by the water seal tank (14). The dehumidified exhaust gas is then transported to the tubular furnace for incineration via the tubular furnace conveying pipeline.

7. The VOC flue gas purification device according to claim 6, characterized in that, The water seal tank (14) is filled with alkaline absorbent liquid to neutralize the acidic components in the exhaust gas. An oil separator (17) is provided at the bottom of the water seal tank (14) and the oil separator (17). A water seal tank circulation pump is also provided between the water seal tank (14) and the oil separator (17).

8. The VOC flue gas purification device according to claim 1, characterized in that, It also includes a nitrogen generator, whose outlet is connected to the waste gas source storage tank via a breather valve. This is used to fill the waste gas source storage tank with nitrogen to create a slight positive pressure protection and reduce the oxygen content of the waste gas system.

9. A method for purifying VOC flue gas, based on the VOC flue gas purification device according to any one of claims 1-8, characterized in that, include: Step S1: The VOC flue gas is introduced into the first treatment unit, and after being condensed by the washing oil seal, some of the naphthalene and high-boiling-point substances are removed. Step S2: The pre-treated flue gas is introduced into the flue gas scrubbing tower (1) and comes into countercurrent contact with the circulating sprayed oil-water mixed absorbent to absorb the VOC components in the flue gas. Step S3: The washed flue gas is sent into the water seal tank (14) via the fan device (11) to neutralize the acidic gas therein; Step S4: After the neutralized flue gas is dehumidified by the demister (16), it is sent into the tubular furnace for incineration. Step S5: The clean gas after incineration is discharged at high altitude after passing the standard test.

10. The VOC flue gas purification method according to claim 9, characterized in that, In step S2, when the moisture content in the circulating absorbent is ≥10% or the naphthalene content is ≥8%, the absorbent is replaced, and the replaced absorbent is returned to the raw material tank for recycling.

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