A resin adsorption-desorption system for exhaust gas treatment

Abstract

The utility model discloses a resin adsorption system for waste gas treatment relates to the field of waste gas treatment, including pretreatment unit, compression condensing unit and resin adsorption unit, and waste gas passes through pretreatment unit, compression condensing unit and resin adsorption unit in proper order, the pretreatment unit is used for neutralizing the pollutant in waste gas, the compression condensing unit is used for condensing the condensable organic gas in waste gas, and the incondensable organic gas enters resin adsorption unit, the resin adsorption unit includes three resin adsorption towers, and two resin adsorption towers are used for gas adsorption, and another resin adsorption tower analysis is ready for use, and the system adopts the combination process of " pretreatment + compression condensing + resin adsorption", realizes the step -by -step processing of different concentration, multicomponent waste gas, and ensures that the discharge reaches the standard.

Description

Technical Field

[0001] This utility model relates to the field of waste gas treatment, specifically a resin adsorption-desorption system for waste gas treatment. Background Technology

[0002] Industrial production processes generate large amounts of waste gas containing volatile organic compounds and organic solvents. If this waste gas is discharged directly without effective treatment, it will not only cause serious pollution to the atmospheric environment and endanger human health, but also lead to the waste of valuable resources. Currently, there are various technologies for waste gas recovery and treatment. Among them, adsorption is widely used due to its simple equipment and convenient operation. However, commonly used adsorbents such as activated carbon have limited adsorption capacity, are prone to saturation, require frequent regeneration, and may generate secondary pollution during the regeneration process. Condensation methods lower the temperature of the waste gas, causing condensable components to condense and separate. This method is effective for high-concentration waste gas recovery, but for low-concentration waste gas, the temperature needs to be lowered to very low levels, resulting in extremely high energy consumption and unsatisfactory recovery efficiency. Membrane separation utilizes the difference in permeation rates of different gases within a membrane to achieve separation. It has advantages such as high separation efficiency and low energy consumption. However, membrane materials are expensive, and the membrane is sensitive to impurities in the waste gas, easily causing membrane fouling, affecting membrane lifespan and separation performance. Therefore, strict pretreatment of the waste gas is required, increasing treatment costs and complexity. Given the limitations of existing single waste gas recovery technologies, which cannot simultaneously meet the requirements of efficient, economical, and environmentally friendly waste gas treatment and recovery, it is particularly necessary to develop a waste gas recovery system that integrates the advantages of multiple technologies and can effectively overcome the above-mentioned defects. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a resin adsorption-desorption system for waste gas treatment, thereby addressing the deficiencies of the prior art.

[0004] The purpose of this utility model is achieved through the following technical solution: a resin adsorption-desorption system for waste gas treatment, comprising a pretreatment unit, a compression-condensation unit, and a resin adsorption unit. Waste gas passes sequentially through the pretreatment unit, the compression-condensation unit, and the resin adsorption unit. The pretreatment unit is used to neutralize pollutants in the waste gas. The compression-condensation unit is used to condense condensable organic gases in the waste gas. Non-condensable organic gases enter the resin adsorption unit. The resin adsorption unit includes three resin adsorption towers, two of which are used for gas adsorption, and the other resin adsorption tower is used for desorption and backup.

[0005] Furthermore, the discharge pipe of the resin adsorption tower is connected to a heat exchanger, the heat exchanger is connected to an oil-water separator, and the aqueous phase of the oil-water separator is connected to a buffer tank.

[0006] Furthermore, the buffer tank is connected to a dichloromethane adsorption tank, which is filled with a special resin for dichloromethane to adsorb and purify dichloromethane in the aqueous phase.

[0007] Furthermore, the compression and condensation unit includes a filter, a liquid-injected screw compressor, a gas-liquid separator, a precooler, a condenser, and a liquid storage tank connected in sequence. The first gas outlet of the precooler is connected to a separation membrane assembly, the second gas outlet of the condenser is connected to the precooler, the separation membrane assembly is connected to the filter through a circulation pipe, and the separation membrane assembly is connected to a resin adsorption unit.

[0008] Furthermore, both the resin adsorption tower and the dichloromethane adsorption tank are connected to a steam pipeline via branch pipes, and the drain outlet of the dichloromethane adsorption tank is connected to a precooler.

[0009] Furthermore, an explosion-proof pressure sensor is installed on the pipeline between the filter and the liquid injection screw compressor.

[0010] Furthermore, the resin adsorption tower is filled with a high-performance resin with selective adsorption properties as an adsorbent.

[0011] Furthermore, the pretreatment unit includes an alkaline washing tower and a water washing tower, with the outlet of the alkaline washing tower connected to the inlet of the water washing tower, and the outlet of the water washing tower connected to a filter.

[0012] The beneficial effects of this utility model are: 1. The system adopts a combined process of "pretreatment + compression condensation + resin adsorption". The pretreatment unit neutralizes acidic pollutants through an alkaline washing tower and purifies impurities through a water washing tower, avoiding subsequent equipment corrosion and adsorbent performance degradation. The compression condensation unit efficiently recovers high-concentration condensable organic gases, and the remaining low-concentration non-condensable gases are deeply purified by the resin adsorption unit, realizing the step-by-step treatment of waste gases of different concentrations and multiple components, ensuring that emissions meet standards.

[0013] 2. The resin adsorption unit adopts a three-adsorption tower rotation mode (two adsorption towers and one desorption tower as a backup) to achieve continuous and uninterrupted processing, avoiding the downtime problem caused by regeneration in traditional single-tower equipment; compared with activated carbon, high-performance selective resin adsorbents have advantages such as large adsorption capacity, strong resistance to humidity interference, and stable regeneration performance, reducing the risk of secondary pollution.

[0014] 3. The compression and condensation unit uses a liquid-injected screw compressor and multi-stage heat exchange equipment to condense condensable organic matter into liquid and recover it to a storage tank for resource reuse. Organic matter generated by the resin adsorption tower is further processed by a heat exchanger and oil-water separator to recover effective components. Simultaneously, the membrane separation module recycles incompletely separated gas back into the treatment process, reducing material loss. The steam regeneration system uses centralized power supply via branch pipes, and the wastewater from the dichloromethane adsorption tank is reused in the precooler, significantly reducing energy and water consumption, aligning with the circular economy concept. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the processing flow of a resin adsorption-desorption system for waste gas treatment according to the present invention. Figure 2 This is a schematic diagram of the structure of a resin adsorption unit in a resin adsorption-desorption system for waste gas treatment according to the present invention. In the diagram, 1-alkali washing tower, 2-water washing tower, 3-filter, 4-screw compressor, 5-gas-liquid separator, 6-precooler, 7-condenser, 8-storage tank, 9-separation membrane module, 10-circulation pipe, 11-resin adsorption tower, 12-branch pipe, 13-steam pipe. Detailed Implementation

[0016] Example 1 like Figure 1 and Figure 2 As shown, a resin adsorption-desorption system for waste gas treatment includes a pretreatment unit, a compression-condensation unit, and a resin adsorption unit. Waste gas sequentially passes through these units. The pretreatment unit neutralizes pollutants in the waste gas, the compression-condensation unit condenses condensable organic gases, and the non-condensable organic gases enter the resin adsorption unit. The resin adsorption unit includes three resin adsorption towers 11, two of which are used for gas adsorption, and the third tower is used for desorption and backup. The system employs a combined process of "pretreatment + compression-condensation + resin adsorption." The pretreatment unit neutralizes acidic pollutants through an alkaline washing tower and purifies impurities through a water washing tower, preventing subsequent equipment corrosion and adsorbent performance degradation. The compression-condensation unit efficiently recovers high-concentration condensable organic gases, and the remaining low-concentration non-condensable gases are deeply purified by the resin adsorption unit. This achieves stepped treatment of waste gas with different concentrations and multiple components, ensuring emissions meet standards.

[0017] Furthermore, the resin adsorption tower 11 is filled with a high-performance resin with selective adsorption as the adsorbent. Its "selectivity" is mainly reflected in its targeted adsorption capacity for specific organic pollutants. It can preferentially adsorb target substances in complex waste gas components while reducing the adsorption of irrelevant components, thereby improving purification efficiency and resource recovery purity. A specific example is non-polar macroporous adsorption resin (such as XAD-4 type). This type of resin does not contain polar groups on its surface and has a strong affinity for non-polar benzene compounds such as benzene, toluene, and xylene. In mixed waste gas containing benzene, ethyl acetate, and water vapor, this resin preferentially adsorbs benzene compounds, while adsorbing very little of the more polar ethyl acetate and water vapor. When the waste gas passes through the resin adsorption tower, benzene compounds are retained, and the concentration of benzene compounds in the purified gas can be reduced to below 10 ppm, while ethyl acetate enters the subsequent treatment stage with the gas flow, achieving stepwise separation of different VOCs. Polar macroporous adsorption resins (such as type H103) contain polar groups such as ester and hydroxyl groups in their framework structure, exhibiting significant adsorption selectivity for ketones such as acetone and butanone, as well as esters such as ethyl acetate and butyl acetate. In mixed waste gas containing acetone, cyclohexane, and nitrogen emitted from painting workshops, this resin can adsorb up to 80 mg / g of acetone, while its adsorption capacity for non-polar cyclohexane is only 5 mg / g, and it adsorbs almost no nitrogen. This selectivity allows for the efficient recovery of acetone solvent from waste gas, achieving a purity of over 95% after regeneration.

[0018] Example 2 Based on Example 1, such as Figure 1As shown, the compression and condensation unit includes a filter 3, a liquid-injected screw compressor 4, a gas-liquid separator 5, a precooler 6, a condenser 7, and a liquid storage tank 8 connected in sequence. An explosion-proof pressure sensor is installed on the pipeline between the filter 3 and the liquid-injected screw compressor 4. The first gas outlet of the precooler 6 is connected to a separation membrane assembly 9, and the second gas outlet of the condenser 7 is connected to the precooler 6. The separation membrane assembly 9 is connected to the filter 3 via a circulation pipe 10 and is also connected to a resin adsorption unit. The pretreatment unit includes an alkaline scrubbing tower 1 and a water scrubbing tower 2. The outlet of the alkaline scrubbing tower 1 is connected to the inlet of the water scrubbing tower 2. The outlet of water scrubbing tower 2 is connected to filter 3. Exhaust gas enters alkaline scrubbing tower 1, where it neutralizes acidic pollutants. The exhaust gas from alkaline scrubbing tower 1 then passes through water scrubbing tower 2 to remove residual alkali. After water spraying, the mixed gas passes through filter 3 to remove impurities and protect the compressor. When the explosion-proof pressure sensor at the system inlet receives a gas pressure signal, the equipment starts. Volatile gas enters the liquid-injected screw compressor 4, which automatically operates and adapts its operating frequency to balance the corresponding intake volume. The volatile gas is compressed, and the pressure rises to 0.8 MPa (G). The compressed volatile gas passes through gas-liquid separator 5, where most of the condensate is separated from the volatile gas. The volatile gas then enters precooler 6 and condenser 7 for condensation. A large amount of organic gas in the volatile gas is condensed into liquid and enters the liquid storage tank 8. The non-condensable volatile gas, after pre-cooling and heating, flows into the gas separation membrane assembly 9. Most of the organic gas in the non-condensable gas passes through the gas separation membrane (permeable side), is enriched and concentrated, and then returns to the inlet of the liquid injection screw compressor 4, where it is superimposed and re-enters the compression and condensation process. The air in the non-condensable gas (permeable side) still contains a small amount of organic gas, which will be processed in the resin adsorption unit. The compressed membrane condensate tail gas is pressurized by a fan and then enters the resin adsorption unit for adsorption treatment.

[0019] Example 3 Based on Example 2, such as Figure 2As shown, the discharge pipe of resin adsorption tower 11 is connected to a heat exchanger, which is connected to an oil-water separator. The aqueous phase of the oil-water separator is connected to a buffer tank, which is connected to a dichloromethane adsorption tank. The dichloromethane adsorption tank is filled with dichloromethane-specific resin for adsorbing and purifying dichloromethane in the aqueous phase. VOCs and other solvents in the exhaust gas are retained in the adsorption tower, thus purifying the exhaust gas. Two resin adsorption towers 11 are connected in series for adsorption, with one serving as a standby for desorption. Each resin adsorption tower is filled with 1 m³ of resin. One resin adsorption tower 11 adsorbs, and after it becomes saturated, it is regenerated; the other resin adsorption tower 11 operates, and so on. Both the resin adsorption tower 11 and the dichloromethane adsorption tank are connected to a steam pipe 13 via branch pipes 12. The drain outlet of the dichloromethane adsorption tank is connected to a precooler 6. After adsorption saturation, the solvent in the adsorption resin is regenerated using steam at 0.099 MPa. Organic matter is carried out of the resin pores by the steam, condensed in a heat exchanger, and then separated in an oil-water separator for recycling. The separated aqueous phase is buffered in a buffer tank for further treatment. A cooling water tank is used to cool the resin adsorption tower 11 and circulate the water to rapidly cool the resin bed. Compressed air is then used to pressurize the water in the resin column back into the cooling water tank. This tank serves both a rapid cooling function and a fire-fighting function, using compressed air to pressurize and drain the water from the resin column for later use. Aqueous phase treatment: The liquid phase after compression condensation and resin desorption condensation, separated in the oil-water separator, is buffered in the buffer tank. Since dichloromethane is slightly soluble in water, the water contains a small amount of dichloromethane. According to actual requirements, wastewater containing dichloromethane is not allowed to be discharged into the wastewater treatment plant; therefore, the aqueous phase requires further treatment. Advanced aqueous phase treatment uses a special dichloromethane-specific resin for water treatment to adsorb and purify the dichloromethane in the aqueous phase. The purified water is discharged into the wastewater treatment plant. After the resin is saturated, it is desorbed by steam. The desorbed steam enters the precooler 6 for condensation. The condensed waste liquid undergoes oil-water separation, thus forming a closed-loop treatment system that prevents the generation of dichloromethane hazardous waste.

Claims

1. A resin adsorption-desorption system for waste gas treatment, characterized in that, The system includes a pretreatment unit, a compression and condensation unit, and a resin adsorption unit. The waste gas passes through the pretreatment unit, the compression and condensation unit, and the resin adsorption unit in sequence. The pretreatment unit is used to neutralize pollutants in the waste gas. The compression and condensation unit is used to condense condensable organic gases in the waste gas. Non-condensable organic gases enter the resin adsorption unit. The resin adsorption unit includes three resin adsorption towers, two of which are used for gas adsorption, and the third resin adsorption tower is used for desorption and backup.

2. The resin adsorption-desorption system for waste gas treatment according to claim 1, characterized in that, The discharge pipe of the resin adsorption tower is connected to a heat exchanger, the heat exchanger is connected to an oil-water separator, and the aqueous phase of the oil-water separator is connected to a buffer tank.

3. The resin adsorption-desorption system for waste gas treatment according to claim 2, characterized in that, The buffer tank is connected to a dichloromethane adsorption tank, which is filled with a special resin for dichloromethane to adsorb and purify dichloromethane in the aqueous phase.

4. The resin adsorption-desorption system for waste gas treatment according to claim 3, characterized in that, The compression and condensation unit includes a filter, a liquid-injecting screw compressor, a gas-liquid separator, a precooler, a condenser, and a liquid storage tank connected in sequence. The first gas outlet of the precooler is connected to a separation membrane assembly, and the second gas outlet of the condenser is connected to the precooler. The separation membrane assembly is connected to the filter through a circulation pipe and is connected to a resin adsorption unit.

5. A resin adsorption-desorption system for waste gas treatment according to claim 4, characterized in that, Both the resin adsorption tower and the dichloromethane adsorption tank are connected to the steam pipeline via branch pipes, and the drain outlet of the dichloromethane adsorption tank is connected to the precooler.

6. The resin adsorption-desorption system for waste gas treatment according to claim 4, characterized in that, An explosion-proof pressure sensor is installed on the pipeline between the filter and the liquid injection screw compressor.

7. The resin adsorption-desorption system for waste gas treatment according to claim 1, characterized in that, The resin adsorption tower is filled with a high-performance resin with selective adsorption properties as the adsorbent.

8. A resin adsorption-desorption system for waste gas treatment according to claim 4, characterized in that, The pretreatment unit includes an alkaline washing tower and a water washing tower. The outlet of the alkaline washing tower is connected to the inlet of the water washing tower, and the outlet of the water washing tower is connected to a filter.

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