System and method for treating chlorine-containing volatile organic compounds

Abstract

The invention relates to a system and a method for treating chlorine-containing volatile organic compounds. The system comprises a pretreatment unit, an adsorption concentration unit, a regeneration unit and a degradation unit which are sequentially connected, wherein the pretreatment unit is used for cooling and dehumidifying high-humidity waste gas; the adsorption concentration unit is filled with a hydrophobic adsorption material for adsorption concentration; the regeneration unit provides hot inert gas for desorption; the degradation unit is a low-temperature plasma-catalytic coupling reactor filled with a specific catalyst which takes TiO2 as a carrier, loads MnOx and CeO2 and is doped with molybdenum or tungsten elements. According to the method, efficient treatment of the chlorine-containing organic matter is achieved through the steps of cooling and dehumidification, adsorption and concentration, hot nitrogen desorption, plasma-catalytic degradation and the like. The method not only can effectively degrade chlorine-containing organic matters, but also remarkably inhibits the generation of dioxin and avoids secondary pollution, meanwhile, has the advantages of adapting to a high-humidity environment, being low in energy consumption and high in safety, and remarkably improves industrial application value and environmental benefits.

Description

Technical Field

[0001] This invention relates to the technical field of environmental protection and waste gas treatment, and in particular to a system and method for treating chlorine-containing volatile organic compounds. Background Technology

[0002] Chlorine-containing volatile organic compounds (CVOCs), such as dichloromethane, chlorobenzene, and trichloroethylene, are widely derived from industries such as chemical, pesticide, pharmaceutical, coating, and hazardous waste disposal. These substances are characterized by high toxicity and strong environmental persistence.

[0003] Currently, combustion is the common method for treating such substances. Thermal combustion (RTO) requires maintaining high temperatures (>760°C), which consumes a lot of energy. Moreover, high temperatures make it easier to promote the formation of dioxins, causing secondary pollution problems. In addition, combustion is difficult to deal with common industrial waste gas conditions with low concentration and high humidity, and cannot meet the needs of industrial development and environmental protection. Summary of the Invention

[0004] The present invention aims to provide a system and method for treating chlorinated volatile organic compounds, in order to solve the problems of low efficiency, high energy consumption and secondary pollution caused by combustion methods in the background art when treating chlorinated volatile organic compounds.

[0005] To address the aforementioned technical problems, in a first aspect, the present invention provides a system for treating chlorine-containing volatile organic compounds, comprising: The pretreatment unit is used to cool and dehumidify the intake air; An adsorption concentration unit is connected to the pretreatment unit. The adsorption concentration unit is filled with hydrophobic adsorption material for adsorbing organic matter in the pretreated waste gas. A regeneration unit, connected to the adsorption concentration unit, is used to supply heated inert gas to the adsorption concentration unit for desorption. The degradation unit, connected to the adsorption and concentration unit, is used to degrade the high-concentration organic gases generated during desorption. The degradation unit is a low-temperature plasma-catalytic coupling reactor, which includes a dielectric barrier discharge plasma generator and a catalyst disposed in the discharge region of the plasma generator. The catalyst uses TiO2 as a support, is loaded with MnOx and CeO2 as active components, and is doped with molybdenum or tungsten elements, and is used to degrade chlorinated volatile organic compounds and inhibit the formation of dioxins through plasma synergy.

[0006] In one embodiment, the molar ratio of MnOx to CeO2 is 1:(0.5-2), and the doping amount of molybdenum or tungsten is 0.5% to 3% of the total mass of the catalyst.

[0007] In one embodiment, the hydrophobic adsorbent is at least one of hydrophobically modified zeolite molecular sieves, metal-organic framework materials, hydrophobic activated carbon, or high-silica molecular sieves. The silica-alumina ratio of the zeolite molecular sieve is greater than 200.

[0008] In one embodiment, the adsorption concentration unit includes at least two adsorption tanks arranged in parallel and a valve group connected to the adsorption tanks; The valve assembly can switch the airflow so that at least one adsorption tank performs an adsorption operation while at least another adsorption tank performs a desorption or cooling operation.

[0009] In one embodiment, the regeneration unit includes an inert gas source, a heater, and a gas recovery pipeline, wherein a condenser is provided on the gas recovery pipeline for pre-cooling the high-concentration organic gas desorbed.

[0010] In one embodiment, a purification unit is also included, which is disposed at the outlet end of the degradation unit for capturing trace amounts of pollutants and acidic gases remaining in the gas after the reaction.

[0011] In one embodiment, a control unit is further included. The control unit is electrically connected to the pretreatment unit, the adsorption concentration unit, and the regeneration unit, respectively, and is used to control the operating parameters of the pretreatment unit and to control the mode switching and gas flow direction between the adsorption concentration unit and the regeneration unit.

[0012] Secondly, the present invention also provides a method for treating chlorine-containing volatile organic compounds using the above-described system, comprising the following steps: S1: Pass the chlorine-containing volatile organic compound waste gas into the pretreatment unit to reduce the temperature of the waste gas to 5℃~15℃ and the relative humidity to below 30%; S2: The pretreated waste gas is passed into the adsorption tank of the adsorption concentration unit in adsorption mode, and the hydrophobic adsorption material is used to adsorb the organic matter in the waste gas. S3: When the adsorption concentration unit is saturated, switch to desorption mode, and introduce high-temperature inert gas into the adsorption concentration unit through the regeneration unit to desorb and obtain high-concentration organic gas. S4: The high-concentration organic gas is introduced into the plasma-catalyst coupled reactor, where a degradation reaction is carried out under the synergistic effect of plasma and catalyst; S5: The exhaust gas produced by the degradation reaction will be purified before being discharged.

[0013] In one embodiment, in step S3, the inert gas is nitrogen, and the desorption temperature is 100°C to 200°C.

[0014] In one embodiment, the energy density of the low-temperature plasma-catalytic coupling reactor is 100 J / L to 500 J / L. The above-described system and method for treating chlorinated volatile organic compounds (VOCs) include a pretreatment unit, an adsorption concentration unit, a regeneration unit, and a degradation unit connected in sequence. The pretreatment unit cools and dehumidifies the high-humidity inlet gas; the adsorption concentration unit is filled with hydrophobic adsorbent material for adsorbing organic matter; the regeneration unit provides heated inert gas for desorption; and the degradation unit is a low-temperature plasma-catalytic coupling reactor filled with a specific catalyst supported on TiO2, loaded with MnOx and CeO2, and doped with molybdenum or tungsten. The method includes: cooling and dehumidifying the waste gas, followed by adsorption concentration using the hydrophobic adsorbent material; after adsorption saturation, desorption using high-temperature inert gas to generate a high concentration of organic gas; and finally, passing the desorbed gas into the plasma-catalytic reactor for degradation. This invention not only effectively degrades chlorinated organic compounds but also significantly inhibits the formation of dioxins, avoiding secondary pollution. It also has advantages such as adaptability to high-humidity environments, low energy consumption, and high safety, significantly improving its industrial application value and environmental benefits. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a block diagram illustrating the system control principle of the present invention; Figure 3 This is a schematic diagram of the method flow of the present invention.

[0016] Among them, 10 is the pretreatment unit, 20 is the adsorption and concentration unit, 210 is the first adsorption tank, 220 is the second adsorption tank, 230 is the valve group, 30 is the regeneration unit, 310 is the inert gas source, 320 is the heater, 40 is the degradation unit, 50 is the purification unit, 60 is the condenser, and 70 is the control unit. Detailed Implementation

[0017] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention, such as passing the exhaust gas generated in step S4 into the purification unit for purification before emission. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0018] As used herein, the terms “prepared from” and “comprising” are synonymous. The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0019] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0020] Furthermore, the indefinite articles “a” and “an” preceding the elements or components of this invention do not impose any limitation on the quantity requirement (i.e., the number of times) of the elements or components. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers to the singular form.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] like Figure 1As shown, the present invention provides a system for treating chlorine-containing volatile organic compounds, including a pretreatment unit 10, an adsorption concentration unit 20, a regeneration unit 30, and a degradation unit 40. The outlet of the pretreatment unit 10 is connected to the inlet of the adsorption concentration unit 20. The adsorption concentration unit 20 includes at least two adsorption tanks arranged in parallel and a valve group 230 connected to the adsorption tanks. The valve group 230 can switch the airflow, so that at least one adsorption tank performs adsorption while at least another adsorption tank performs desorption or cooling. In this invention, the waste gas, after being cooled and dehumidified by the pretreatment unit 10, is guided by the valve group 230 into the adsorption tank in adsorption mode. The inlet of the adsorption tank in desorption mode is connected to the outlet of the regeneration unit 30. The regeneration unit 30 provides heated inert gas to the adsorption tank in desorption mode for desorption. The outlet of the adsorption tank in desorption mode is switched by the valve group 230 and connected to a dedicated pipeline leading to the degradation unit 40 for degrading the high-concentration organic gas generated during desorption.

[0023] Furthermore, the adsorption concentration unit 20 is filled with a hydrophobic adsorption material, which is at least one of hydrophobically modified zeolite molecular sieves, metal-organic framework materials, hydrophobic activated carbon, or high-silica molecular sieves; wherein the silica-to-alumina ratio of the zeolite molecular sieve is greater than 200. In this invention, the hydrophobic adsorption material can preferentially adsorb nonpolar or weakly polar CVOCs molecules and repel water molecules, thereby ensuring adsorption capacity and efficiency in high-humidity waste gas.

[0024] Furthermore, the regeneration unit 30 includes an inert gas source 310, a heater 320, and a gas recovery pipeline. A condenser 60 is installed on the gas recovery pipeline to pre-cool the high-concentration organic gas desorbed, thereby reducing the total energy consumption of the system and improving economic efficiency.

[0025] Furthermore, degradation unit 40 is a low-temperature plasma-catalytic coupling reactor, which includes a dielectric barrier discharge plasma generator and a catalyst disposed within the discharge region of the plasma generator. The catalyst uses TiO2 as a support, loaded with MnOx and CeO2 as active components, and doped with molybdenum or tungsten elements to degrade chlorinated volatile organic compounds and inhibit dioxin formation through plasma synergy. Specifically, the molar ratio of MnOx to CeO2 is 1:(0.5-2), and the doping amount of molybdenum or tungsten elements is 0.5%-3% of the total mass of the catalyst. In this invention, MnOx provides excellent oxidation activity, and CeO2 promotes the deep oxidation of intermediate products with its excellent oxygen storage and release capacity, with the two working synergistically; while the doping of molybdenum or tungsten elements can modulate the surface acidity and redox properties of the catalyst, preferentially adsorbing and destroying C-Cl bonds, effectively inhibiting the condensation reaction of benzene rings, i.e., inhibiting the dioxin formation pathway.

[0026] This invention addresses humidity interference through a pretreatment unit 10, achieves efficient enrichment of low-concentration waste gas through an adsorption and concentration unit 20, safely generates high-concentration, oxygen-free desorbed gas through a regeneration unit 30, and finally achieves complete degradation of CVOCs and effective suppression of dioxins through a specially designed low-temperature plasma-catalytic coupling reactor. This system constitutes a synergistic and efficient organic whole.

[0027] In addition, the system also includes a purification unit 50, which is located at the outlet of the degradation unit 40. The purification unit 50 is used to capture trace pollutants and acidic gases remaining in the gas after the reaction, ensuring that the final emission gas fully meets the standards and avoiding secondary pollution.

[0028] like Figure 2 As shown, the present invention also includes a control unit 70, which is electrically connected to the pretreatment unit 10, the adsorption concentration unit 20, and the regeneration unit 30 respectively. The control unit 70 is used to control the operating parameters of the pretreatment unit 10 and to control the mode switching and gas flow direction between the adsorption concentration unit 20 and the regeneration unit 30, so as to realize the automated and intelligent operation of the entire system, which is conducive to improving the treatment effect of waste gas, ensuring the stability of continuous industrial production, and reducing energy consumption.

[0029] like Figure 3 As shown, the present invention also provides a method for treating chlorine-containing volatile organic compounds using the above-described system, comprising the following steps: S1: Pass the chlorine-containing volatile organic compound waste gas into the pretreatment unit 10 to reduce the temperature of the waste gas to 5℃~15℃ and the relative humidity to below 30%; S2: The pretreated waste gas is passed into the adsorption tank of the adsorption concentration unit 20 in adsorption mode, and the organic matter in the waste gas is adsorbed by the hydrophobic adsorption material. S3: When the adsorption concentration unit 20 is saturated, it switches to desorption mode and introduces high-temperature inert gas into the adsorption concentration unit 20 through the regeneration unit 30 to desorb and obtain high-concentration organic gas; wherein, the inert gas is nitrogen and the desorption temperature is 100℃~200℃. S4: The above-mentioned high-concentration organic gas is introduced into the plasma-catalytic coupling reactor, and the degradation reaction is carried out under the synergistic effect of plasma and catalyst. The energy density of the low-temperature plasma-catalytic coupling reactor is controlled to be 100J / L~500J / L. S5: The exhaust gas generated in step S4 is passed into the purification unit 50 for purification treatment before being discharged.

[0030] Example 1 System setup: By Figure 1The system is constructed as follows: Pretreatment unit 10 is a surface cooler; adsorption concentration unit 20 consists of two parallel adsorption tanks filled with hydrophobic zeolite molecular sieves with a silica-to-alumina ratio of 300; regeneration unit 30 is equipped with a nitrogen cylinder and an electric heater 320; degradation unit 40 is a dielectric barrier discharge reactor containing a catalyst (mesoporous TiO2 loaded with MnOx and CeO2 (molar ratio 1:1) and doped with 2wt% Mo).

[0031] It should be noted that the bottom of the pretreatment unit 10 is equipped with an automatic condensate drain valve to periodically remove condensate generated during the cooling and dehumidification process, preventing water accumulation inside the system. A plate heat exchanger is also added to the gas recovery pipeline of the regeneration unit 30 to exchange the waste heat of the high-temperature desorption tail gas with the ambient temperature waste gas entering the pretreatment unit 10, thereby realizing heat energy recovery and reducing the total energy consumption of the system. A differential pressure sensor is installed in the adsorption tank of the adsorption concentration unit 20. The control unit 70 is connected to the differential pressure sensor. When the bed pressure difference is detected to exceed the preset threshold, an alarm can be issued or the desorption procedure can be triggered in advance, serving as a double guarantee in addition to concentration monitoring.

[0032] Simulated exhaust gas: chlorobenzene concentration 200 mg / m³, gas flow rate 2000 m³ / h, temperature 40℃, relative humidity 80%.

[0033] First, the waste gas is introduced into the pretreatment unit 10 for cooling and dehumidification, reducing the waste gas temperature to 10℃ and the relative humidity to below 30%. Then, the pretreated, dry, and cold waste gas is led to the first adsorption tank 210 through valve group 230. The waste gas passes through the hydrophobic zeolite inside the first adsorption tank 210, where chlorobenzene molecules are selectively adsorbed. The purified gas, meeting the emission standards, is then discharged through the first outlet. After 4 hours, the online concentration detector at the first outlet shows an increase in chlorobenzene concentration. The control unit 70 automatically triggers a switch, cutting off the inlet and outlet of the first adsorption tank 210. Simultaneously, the second adsorption tank 220, which has already been cooled, is switched into the main gas path to continue adsorption operations, ensuring the continuity of the treatment process. During this process, after the first adsorption tank 210 completes desorption, it is cooled with room temperature nitrogen gas in preparation for the next round of adsorption. When the second adsorption tank 220 becomes saturated, the system switches again to desorb from the second adsorption tank 220, thus performing a cyclical operation.

[0034] Next, the regeneration unit 30 is started, and nitrogen is drawn from the gas source and heated to 180°C by the heater 320. At this time, the high-temperature nitrogen enters the first adsorption tank 210 in desorption mode through the valve group 230. The hot nitrogen desorbs the chlorobenzene molecules adsorbed on the hydrophobic zeolite to form a high-concentration, low-volume chlorobenzene-nitrogen mixture. At this time, the chlorobenzene concentration is about 2000 mg / m³.

[0035] Then, the high-temperature desorbed gas is passed through condenser 60 to reduce the temperature from 180℃ to 60℃. The cooled, high-concentration desorbed gas enters the dielectric barrier discharge reactor, where a high voltage is applied to generate a low-temperature plasma rich in high-energy electrons under the action of dielectric barrier discharge. At the same time, the desorbed gas passes through the Mn-Ce-Mo / TiO2 catalyst filled in the discharge zone. Under the synergistic effect of the plasma and the catalyst, chlorobenzene molecules are rapidly destroyed, and C-C bonds and C-Cl bonds are broken, resulting in deep oxidation into CO2, H2O, and HCl. During this process, the plasma energy density is controlled at 300J / L to ensure efficient degradation. The exhaust gas after the degradation reaction enters the purification unit 50 for purification treatment before being discharged.

[0036] After the system was running stably, the total VOCs concentration at the emission port of purification unit 50 was measured to be <10 mg / m³ by gas chromatography. 3 And calculate the chlorobenzene removal rate.

[0037] Chlorobenzene removal rate = [(inlet concentration - outlet concentration) / inlet concentration] × 100% =(200mg / m³-10mg / m³) / 200mg / m³×100%=95.0% Meanwhile, dioxins were detected according to the standard "Determination of Dioxins in Ambient Air and Exhaust Gas by Isotope Dilution / High-Resolution Gas Chromatography-High-Resolution Mass Spectrometry" (HJ77.2—2025), and their toxic equivalent (TEQ) was found to be 0.05 ng TEQ / m³.

[0038] In summary, the chlorobenzene removal rate reached 95%, and the dioxin toxicity equivalent was only 0.05 ng TEQ / m³, far below the emission standard (1.0 ng TEQ / m³). This demonstrates that the treatment system of this invention can not only efficiently degrade chlorinated volatile organic compounds, but also inhibit the formation of dioxins, avoiding secondary pollution and meeting environmental protection requirements.

[0039] In addition, to verify the long-term stability of the catalyst, the system of Example 1 was subjected to a 500-hour continuous operation test, with the outlet chlorobenzene concentration and the residual chloride ion rate of the catalyst measured every 100 hours. The results showed that after 500 hours of operation, the chlorobenzene removal rate remained above 92%, and the residual chloride ion rate of the catalyst was less than 1.5 wt%, indicating that the Mn-Ce-Mo / TiO2 catalyst of the present invention has excellent resistance to chlorine poisoning and long-term stability.

[0040] Comparative Example 1-1 The difference between this comparative example and Example 1 is that no catalyst is added.

[0041] After the system was running stably, the total VOCs concentration at the emission port of purification unit 50 was measured to be <50 mg / m³ by gas chromatography.3 And calculate the chlorobenzene removal rate.

[0042] Chlorobenzene removal rate = [(inlet concentration - outlet concentration) / inlet concentration] × 100% =(200mg / m³-50mg / m³) / 200mg / m³×100%=75.0% Meanwhile, dioxins were detected according to the standard "Determination of Dioxins in Ambient Air and Exhaust Gas by Isotope Dilution / High-Resolution Gas Chromatography-High-Resolution Mass Spectrometry" (HJ77.2—2025), and their toxic equivalent (TEQ) was found to be 0.85 ng TEQ / m³.

[0043] The results show that the chlorobenzene removal rate was 75%, and the dioxin TEQ was as high as 0.85 ng TEQ / m³. This indicates that in this comparative example, without a catalyst, although plasma can degrade some pollutants, it will trigger serious side reactions and generate a large number of highly toxic byproducts.

[0044] Comparative Examples 1-2 The difference between this comparative example and Example 1 is that a conventional catalyst (Pt / Pd / Al2O3) is used.

[0045] During the initial operation of the system, the total VOCs concentration at the emission port of purification unit 50 was measured by gas chromatography to be <20 mg / m³. 3 And calculate the chlorobenzene removal rate.

[0046] Chlorobenzene removal rate = [(inlet concentration - outlet concentration) / inlet concentration] × 100% =(200mg / m³-20mg / m³) / 200mg / m³×100%=90.0% After 6 hours of system operation, gas chromatography analysis showed that the total VOCs concentration at the emission port of purification unit 50 was <100 mg / m³. 3 And calculate the chlorobenzene removal rate.

[0047] Chlorobenzene removal rate = [(inlet concentration - outlet concentration) / inlet concentration] × 100% =(200mg / m³-100mg / m³) / 200mg / m³×100%=50.0% Meanwhile, dioxins were detected according to the standard "Determination of Dioxins in Ambient Air and Exhaust Gas by Isotope Dilution / High-Resolution Gas Chromatography-High-Resolution Mass Spectrometry" (HJ77.2—2025), and their toxic equivalent (TEQ) was found to be 0.35 ng TEQ / m³.

[0048] The results show that the chlorobenzene removal rate can reach 90% in the initial stage of system operation. However, after 6 hours of continuous operation, the efficiency rapidly drops to 50% due to chlorine poisoning, and the dioxin TEQ is 0.35 ng TEQ / m³. Although the toxicity of Comparative Examples 1-2 is lower than that of Comparative Example 1-1, it is still much higher than that of the present invention. This demonstrates that the doping of molybdenum or tungsten in the present invention can modulate the acidic sites on the catalyst surface, preferentially adsorb and break C-Cl bonds, and simultaneously inhibit the condensation reaction pathway of benzene rings during degradation, thereby effectively blocking the formation of dioxins from a mechanistic perspective.

[0049] Example 2 System setup: By Figure 1 The system is constructed as follows: Pretreatment unit 10 is a surface cooler; adsorption concentration unit 20 consists of two parallel adsorption tanks filled with hydrophobic zeolite molecular sieves with a silica-to-alumina ratio of 300; regeneration unit 30 is equipped with a nitrogen cylinder and an electric heater 320; degradation unit 40 is a dielectric barrier discharge reactor containing a catalyst (mesoporous TiO2 loaded with MnOx and CeO2 (molar ratio 1:1) and doped with 2wt% Mo).

[0050] Simulated exhaust gas: chlorobenzene concentration 150 mg / m³, gas flow rate 2000 m³ / h, temperature 40℃, relative humidity 80%.

[0051] First, the waste gas is introduced into the pretreatment unit 10 for cooling and dehumidification, reducing the waste gas temperature to 10℃ and the relative humidity to below 30%. Then, the pretreated, dry, and cold waste gas is led to the first adsorption tank 210 through valve group 230. The waste gas passes through the hydrophobic zeolite inside the first adsorption tank 210, where chlorobenzene molecules are selectively adsorbed. The purified gas, meeting the emission standards, is then discharged through the first outlet. After 6 hours, the online concentration detector at the first outlet shows an increase in chlorobenzene concentration. The control unit 70 automatically triggers a switch, cutting off the inlet and outlet of the first adsorption tank 210. Simultaneously, the second adsorption tank 220, which has already been cooled, is switched into the main gas path to continue adsorption operations, ensuring the continuity of the treatment process. During this process, after the first adsorption tank 210 completes desorption, it is cooled with room temperature nitrogen gas in preparation for the next round of adsorption. When the second adsorption tank 220 becomes saturated, the system switches again to desorb from the second adsorption tank 220, thus performing a cyclical operation.

[0052] Next, the regeneration unit 30 is started, and nitrogen is drawn from the gas source and heated to 180°C by the heater 320. At this time, the high-temperature nitrogen enters the first adsorption tank 210 in desorption mode through the valve group 230. The hot nitrogen desorbs the chlorobenzene molecules adsorbed on the hydrophobic zeolite to form a high-concentration, low-volume chlorobenzene-nitrogen mixture. At this time, the chlorobenzene concentration is about 2000 mg / m³.

[0053] Then, the high-temperature desorbed gas is passed through condenser 60 to reduce the temperature from 180℃ to 60℃. The cooled, high-concentration desorbed gas enters the dielectric barrier discharge reactor, where a high voltage is applied to generate a low-temperature plasma rich in high-energy electrons under the action of dielectric barrier discharge. At the same time, the desorbed gas passes through the Mn-Ce-Mo / TiO2 catalyst filled in the discharge zone. Under the synergistic effect of the plasma and the catalyst, chlorobenzene molecules are rapidly destroyed, and C-C bonds and C-Cl bonds are broken, resulting in deep oxidation into CO2, H2O, and HCl. During this process, the plasma energy density is controlled at 300J / L to ensure efficient degradation. The exhaust gas after the degradation reaction enters the purification unit 50 for purification treatment before being discharged.

[0054] After the system was running stably, the total VOCs concentration at the emission port of purification unit 50 was measured by gas chromatography to be <5 mg / m³. 3 And calculate the chlorobenzene removal rate.

[0055] Chlorobenzene removal rate = [(inlet concentration - outlet concentration) / inlet concentration] × 100% =(150mg / m³-5mg / m³) / 150mg / m³×100%=96.7% Meanwhile, dioxins were detected according to the standard "Determination of Dioxins in Ambient Air and Exhaust Gas by Isotope Dilution / High-Resolution Gas Chromatography-High-Resolution Mass Spectrometry" (HJ77.2—2025), and their toxic equivalent (TEQ) was found to be 0.05 ng TEQ / m³.

[0056] In summary, the chlorobenzene removal rate was 96.7%, and the dioxin toxicity equivalent was only 0.05 ng TEQ / m³, far below the emission standards. This demonstrates that the hydrophobic material can maintain a longer effective working time in extremely humid environments, ensuring the stability and economy of the system operation.

[0057] Comparative Example 2-1 The difference between this comparative example and Example 2 is that the adsorbent is ordinary coal-based activated carbon.

[0058] Under the same high humidity exhaust gas conditions, activated carbon's adsorption capacity for chlorobenzene drops sharply due to its strong adsorption of water vapor. It breaks through after only 1 hour of operation, requiring frequent switching of desorption, resulting in extremely high energy consumption and instability. It is impossible to calculate a stable total removal rate for the system.

[0059] Comparative Example 2-2 The difference between this comparative example and Example 2 is that the adsorbent is a hydrophobic zeolite molecular sieve with a silicon-to-aluminum ratio of 100.

[0060] After approximately 3 hours of system operation, the total VOCs concentration at the emission port of purification unit 50 was measured by gas chromatography to be <30 mg / m³. 3And calculate the chlorobenzene removal rate.

[0061] Chlorobenzene removal rate = [(inlet concentration - outlet concentration) / inlet concentration] × 100% =(150mg / m³-30mg / m³) / 150mg / m³×100%=80% Meanwhile, dioxins were detected according to the standard "Determination of Dioxins in Ambient Air and Exhaust Gas by Isotope Dilution / High-Resolution Gas Chromatography-High-Resolution Mass Spectrometry" (HJ77.2—2025), and their toxic equivalent (TEQ) was found to be 0.065 ng TEQ / m³.

[0062] The results show that the adsorption capacity and stability (3-hour breakthrough) of the zeolite with a low silica-alumina ratio (100) are still far inferior to those of the hydrophobic zeolite with a high silica-alumina ratio (>200) of the present invention (6-hour breakthrough). This proves that a high silica-alumina ratio can ensure the long-term stable operation of the adsorbent in a high-humidity environment.

[0063] Example 3 System setup: By Figure 1 The system is constructed as follows: Pretreatment unit 10 is a surface cooler; adsorption concentration unit 20 consists of two parallel adsorption tanks filled with hydrophobic zeolite molecular sieves with a silica-to-alumina ratio of 300; regeneration unit 30 is equipped with a nitrogen cylinder and heater 320; degradation unit 40 is a dielectric barrier discharge reactor containing a catalyst (mesoporous TiO2 loaded with MnOx and CeO2 (molar ratio 1:1) and doped with 2wt% Mo).

[0064] Simulated exhaust gas: chlorobenzene concentration 100 mg / m³, gas flow rate 10000 m³ / h, temperature 40℃, relative humidity 80%.

[0065] First, the waste gas is introduced into the pretreatment unit 10 for cooling and dehumidification, reducing the waste gas temperature to 10℃ and the relative humidity to below 30%. Then, the pretreated, dry, and cold waste gas is led to the first adsorption tank 210 through valve group 230. The waste gas passes through the hydrophobic zeolite inside the first adsorption tank 210, where chlorobenzene molecules are selectively adsorbed. The purified gas, meeting the emission standards, is then discharged through the first outlet. After 4 hours, the online concentration detector at the first outlet shows an increase in chlorobenzene concentration. The control unit 70 automatically triggers a switch, cutting off the inlet and outlet of the first adsorption tank 210. Simultaneously, the second adsorption tank 220, which has already been cooled, is switched into the main gas path to continue adsorption operations, ensuring the continuity of the treatment process. During this process, after the first adsorption tank 210 completes desorption, it is cooled with room temperature nitrogen gas in preparation for the next round of adsorption. When the second adsorption tank 220 becomes saturated, the system switches again to desorb from the second adsorption tank 220, thus performing a cyclical operation.

[0066] Next, the regeneration unit 30 is started, and nitrogen is drawn from the gas source and heated to 180°C by the heater 320. At this time, the high-temperature nitrogen enters the first adsorption tank 210 in desorption mode through the valve group 230. The hot nitrogen desorbs the chlorobenzene molecules adsorbed on the hydrophobic zeolite to form a chlorobenzene-nitrogen mixture. At this time, the air volume of the chlorobenzene-nitrogen mixture is 1000 m³ / h and the concentration is 1000 mg / m³.

[0067] Then, the high-temperature desorbed gas is passed through condenser 60 to reduce the temperature from 180℃ to 60℃. The cooled, high-concentration desorbed gas enters the dielectric barrier discharge reactor, where a high voltage is applied to generate a low-temperature plasma rich in high-energy electrons under the action of dielectric barrier discharge. At the same time, the desorbed gas passes through the Mn-Ce-Mo / TiO2 catalyst filled in the discharge zone. Under the synergistic effect of the plasma and the catalyst, chlorobenzene molecules are rapidly destroyed, and C-C bonds and C-Cl bonds are broken, resulting in deep oxidation into CO2, H2O, and HCl. During this process, the plasma energy density is controlled at 300J / L to ensure efficient degradation. The exhaust gas after the degradation reaction enters the purification unit 50 for purification treatment before being discharged.

[0068] Comparative Example 3 The difference from Example 3 is that the adsorption concentration unit 20 is not used, and the raw waste gas of 10,000 m³ / h is directly passed into the plasma-catalytic reactor for treatment.

[0069] For a fair comparison, both systems were designed to achieve a chlorobenzene removal rate of 95%.

[0070] When the chlorobenzene removal rate in Example 3 reaches 95%, the total energy consumption of the entire process is 25 kW·h.

[0071] When the chlorobenzene removal rate in Comparative Example 3 reaches 95%, the total energy consumption of the entire process is 150 kW·h.

[0072] Therefore, it can be seen that, under the premise of achieving the same high purification effect, the total energy consumption of the system in Example 3 is only one-sixth of that in Comparative Example 3, which proves that the technical solution of the present invention effectively improves economic efficiency and reduces energy consumption.

[0073] The results of all the above embodiments and comparative examples are summarized in Table 1: Table 1 This invention addresses humidity interference through a pretreatment unit 10, achieves efficient enrichment of low-concentration waste gas through an adsorption and concentration unit 20, safely generates high-concentration, oxygen-free desorbed gas through a regeneration unit 30, and finally achieves complete degradation of CVOCs and effective suppression of dioxins through a specially designed low-temperature plasma-catalytic coupling reactor. This system constitutes a synergistic and efficient organic whole, significantly improving industrial application value and environmental benefits.

[0074] The options described in the above method embodiments are also applicable to this embodiment, and will not be detailed here. The remaining content of this application's embodiments can be found in the above method embodiments, and will not be repeated in this embodiment.

[0075] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A system for treating chlorine-containing volatile organic compounds, characterized in that, include: The pretreatment unit is used to cool and dehumidify the intake air; An adsorption concentration unit is connected to the pretreatment unit. The adsorption concentration unit is filled with hydrophobic adsorption material for adsorbing organic matter in the pretreated waste gas. A regeneration unit, connected to the adsorption concentration unit, is used to supply heated inert gas to the adsorption concentration unit for desorption. The degradation unit, connected to the adsorption and concentration unit, is used to degrade the high-concentration organic gases generated during desorption. The degradation unit is a low-temperature plasma-catalytic coupling reactor, which includes a dielectric barrier discharge plasma generator and a catalyst disposed in the discharge region of the plasma generator. The catalyst uses TiO2 as a support, is loaded with MnOx and CeO2 as active components, and is doped with molybdenum or tungsten elements, and is used to degrade chlorinated volatile organic compounds and inhibit the formation of dioxins through plasma synergy.

2. The system according to claim 1, characterized in that, The molar ratio of MnOx to CeO2 is 1:(0.5-2), and the doping amount of molybdenum or tungsten is 0.5% to 3% of the total mass of the catalyst.

3. The system according to claim 1, characterized in that, The hydrophobic adsorption material is at least one of hydrophobically modified zeolite molecular sieves, metal-organic framework materials, hydrophobic activated carbon, or high-silica molecular sieves. The silica-alumina ratio of the zeolite molecular sieve is greater than 200.

4. The system according to claim 1, characterized in that, The adsorption concentration unit includes at least two adsorption tanks arranged in parallel and a valve group connected to the adsorption tanks; The valve assembly can switch the airflow so that at least one adsorption tank performs an adsorption operation while at least another adsorption tank performs a desorption or cooling operation.

5. The system according to claim 1, characterized in that, The regeneration unit includes an inert gas source, a heater, and a gas recovery pipeline. A condenser is installed on the gas recovery pipeline to pre-cool the high-concentration organic gas that has been desorbed.

6. The system according to any one of claims 1-5, characterized in that, It also includes a purification unit, which is located at the outlet end of the degradation unit and is used to capture trace pollutants and acidic gases remaining in the gas after the reaction.

7. The system according to any one of claims 1-5, characterized in that, It also includes a control unit, which is electrically connected to the pretreatment unit, the adsorption concentration unit, and the regeneration unit, respectively, and is used to control the operating parameters of the pretreatment unit and the mode switching and gas flow direction between the adsorption concentration unit and the regeneration unit.

8. A method for treating chlorine-containing volatile organic compounds using the system according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Pass the chlorine-containing volatile organic compound waste gas into the pretreatment unit to reduce the temperature of the waste gas to 5℃~15℃ and the relative humidity to below 30%; S2: The pretreated waste gas is passed into the adsorption tank of the adsorption concentration unit in adsorption mode, and the hydrophobic adsorption material is used to adsorb the organic matter in the waste gas. S3: When the adsorption concentration unit is saturated, switch to desorption mode, and introduce high-temperature inert gas into the adsorption concentration unit through the regeneration unit to desorb and obtain high-concentration organic gas. S4: The high-concentration organic gas is introduced into the plasma-catalyst coupled reactor, where a degradation reaction is carried out under the synergistic effect of plasma and catalyst; S5: The exhaust gas produced by the degradation reaction will be purified before being discharged.

9. The method according to claim 8, characterized in that, In step S3, the inert gas is nitrogen, and the desorption temperature is 100℃~200℃.

10. The method according to claim 8, characterized in that, The energy density of the low-temperature plasma-catalytic coupling reactor is 100 J / L to 500 J / L.

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