Dichloroethane tail gas adsorption device and method

Abstract

The invention is suitable for the technical field of waste gas treatment, and provides a dichloroethane tail gas adsorption device and method.The dichloroethane tail gas adsorption device comprises a pretreatment assembly, the output end of the pretreatment assembly communicates with a resin tank set, the resin tank set is provided with two output ends, one output end of the resin tank set is an exhaust end, and the other output end of the resin tank set is an exhaust end; the other output end of the resin tank group is communicated with a condensation assembly, the output end of the condensation assembly is connected with a collection assembly and a condensate water tank in parallel, the collection assembly is communicated with a resin tank column D, and the gas inlet ends of the resin tank group and the resin tank column D are connected with a desorption assembly. The output end of the condensate water tank is communicated with the resin tank group and the spraying opening of the resin tank column D, and the output end of the condensate water tank is communicated with the pretreatment assembly. The device solves the problems of low adsorption rate, large discharge capacity and complicated subsequent treatment process, improves the resource utilization rate through multi-stage adsorption and reasonable reutilization, and is suitable for large-scale industrial production. And cost reduction and benefit increase are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas treatment, and more specifically, to a dichloroethane tail gas adsorption device and method. Background Art

[0002] Ethylene dichloride is an organic compound that has long been used as a solvent, extractant, dry cleaning agent, wetting agent, pesticide manufacturing and raw material for a variety of chemicals. However, ethylene dichloride has a low boiling point and is easily volatilized during industrial production, causing environmental pollution. Therefore, tail gas containing ethylene dichloride needs to be treated by professional equipment to meet standards before it can be discharged.

[0003] The resin filler adsorption method is a new advanced process for resource-based organic tail gas that has just emerged in recent years. Compared with traditional activated carbon and carbon fiber treatment methods, it has better environmental adaptability and performance reliability, higher regeneration efficiency and lower overall operating costs.

[0004] At present, the dichloroethane tail gas adsorption device on the market is equipped with a pretreatment system. The tail gas is pretreated by graphite adsorption, sulfuric acid adsorption, alkali washing, and water washing in sequence to remove large particle impurities in the tail gas and adjust the gas to neutral before the dichloroethane is adsorbed by resin. However, the graphite adsorber is expensive, cumbersome to operate, and needs to be cleaned and maintained regularly, making the system operation complex and costly.

[0005] In the resin tank adsorption part, a three-tank design is usually adopted. During operation, two tanks are connected in series for adsorption, and the other saturated resin tank is simultaneously subjected to resin desorption and reduction, thereby ensuring that the device can continuously perform tail gas treatment operations and improve efficiency. However, resin desorption will produce a large amount of condensed water containing a certain concentration of ethylene dichloride. The treatment method of the prior art is to discharge it together with the previous washing water into the sewage treatment system for unified treatment, which makes the types of compounds in the sewage complex, increases the difficulty of subsequent treatment, and has a low adsorption efficiency;

[0006] Moreover, the pretreatment process and the resin adsorption process in the prior art are one-way series-connected. The tail gas passes through each treatment component in turn, which will produce waste gas and wastewater of different concentrations. These waste gas and wastewater need to be treated in subsequent processes, especially some low-concentration fluids, which require a high time cost for treatment. Summary of the invention

[0007] In view of the shortcomings of the prior art, the object of the present invention is to provide a low-cost dichloroethane tail gas adsorption device with high water resource utilization, high adsorption efficiency and high integration.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A dichloroethane tail gas adsorption device comprises a pretreatment component, the pretreatment component can remove water-soluble and particulate impurities in the tail gas and adjust the gas to be neutral, the output end of the pretreatment component is connected to a resin tank group, the resin tank group can adsorb dichloroethane in the gas, the resin tank group is provided with two output ends, one output end of the resin tank group is an exhaust end, the exhaust end can be communicated with the outside or connected to the air inlet end of the resin tank group, the gas after adsorption is discharged when it reaches the emission standard, and re-enters the resin tank group for secondary adsorption when it does not meet the standard;

[0010] The other output end of the resin tank group is connected to a condensation component, the output end of the condensation component is connected in parallel with a collection component and a condensation tank, the collection component is connected to a resin tank D column, the output end of the resin tank D column is connected to the condensation component, the air inlet end of the resin tank group and the resin tank D column is connected to a desorption component, the exhaust end and the output end of the condensation component are both provided with a VOCs detector, the output end of the condensation tank is connected to the spray port of the resin tank group and the resin tank D column, and the output end of the condensation tank is connected to the pretreatment component;

[0011] When the desorption component desorbs the resin tank, due to the different concentrations of ethylene dichloride in the resin tanks of different processes, mixtures of different concentrations will be produced. The liquids are stored in the collection component and the condensate tank according to the different concentrations. The condensate containing a certain amount of ethylene dichloride in the collection component can be processed by the resin tank D column for secondary treatment, while the low-concentration condensate in the condensate tank can be input into the resin tank group and the resin tank D column and used as water for other front processes in the process, thereby improving resource utilization, reducing costs and increasing efficiency;

[0012] The present invention is further configured as follows: the pretreatment component includes a water scrubber 1, the air inlet end of the water scrubber 1 is the air inlet end of the pretreatment component, the output end of the water scrubber 1 is sequentially connected to a urea spray tower, a plurality of alkali scrubbers and a water scrubber 2, the tail gas is cooled and filtered out of useless components and solid particles after passing through the water scrubber 1, the tail gas then enters the urea spray tower, the nitrogen oxides therein are converted into harmless nitrogen and water, the tail gas then enters a plurality of alkali scrubbers in sequence, the acidic gas therein is neutralized, and finally enters the water scrubber 2, which can remove water-soluble and dust particles in the gas, so as to ensure that the tail gas after pretreatment is a clean neutral gas, avoid corrosion of pipeline equipment, and facilitate subsequent treatment.

[0013] The present invention is further configured as follows: the collecting component comprises an oil-water separator, the input end of the oil-water separator is connected to the output end of the condensing component, the oil output end of the oil-water separator is connected to a solvent tank, the solvent tank collects and outputs dichloroethane condensate, the condensate output end of the oil-water separator is connected to a receiving tank, the receiving tank collects an aqueous solution containing dichloroethane, and the receiving tank is connected to the input end of the resin tank D column; at room temperature, the solubility of dichloroethane in water is 0.869%, the concentration of dichloroethane contained in the condensate separated from the oil-water separator exceeds the emission standard, the condensate is pumped into the resin tank D column again for secondary adsorption, and the desorption products are graded, thereby improving the collection rate and resource utilization rate, being an integrated system with integrated control, avoiding the cumbersome subsequent treatment, and reducing the exhaust gas treatment cost.

[0014] It is further configured as follows: the resin tank group includes an A-pillar, a B-pillar and a C-pillar, and the exhaust ends of the A-pillar, the B-pillar and the C-pillar are all provided with VOCs detectors. After the detection value of one of the VOCs detectors reaches a preset value, the VOCs detector corresponds to a saturated resin tank, the saturated resin tank is disconnected from the pretreatment component, and connected to the desorption component, the other two resin tanks are connected in series with each other and connected to the output end of the pretreatment component, the resin tank group adopts double-tower series adsorption, one of which is separated from the adsorption pipeline when the adsorption is saturated, and the exhaust gas is adsorbed by the other two resin tanks, and the desorption component is started to desorb and restore the saturated resin tank for standby use.

[0015] A method for adsorbing ethylene dichloride tail gas using the above device comprises the following steps:

[0016] S1. Pretreatment: The waste gas is passed into the pretreatment component, and then passes through the water scrubber 1, the urea spray tower, several alkali scrubbers and the water scrubber 2, and then output as neutral gas;

[0017] S2, waste gas enters the resin tank group;

[0018] S21, A-pillar-B-pillar tail gas adsorption: the exhaust gas enters the A-pillar and the B-pillar in turn for adsorption. The VOCs detector at the exhaust end of the B-pillar monitors the content of ethylene dichloride in the exhaust gas after adsorption in real time. If the content meets the standard, it will be discharged. If the content exceeds the standard, it will re-enter S2;

[0019] When the VOCs detector at the exhaust end of the A-pillar detects that the ethylene dichloride content reaches the preset value, the A-pillar is determined to be a saturated resin tank, the exhaust gas enters S22, and the A-pillar enters S3;

[0020] S22, B-pillar-C-pillar tail gas adsorption: the exhaust gas enters the B-pillar and C-pillar in turn for adsorption. The VOCs detector at the exhaust end of the C-pillar monitors the content of ethylene dichloride in the exhaust gas after adsorption in real time. If the content meets the standard, it will be discharged. If the content exceeds the standard, it will re-enter S2;

[0021] When the VOCs detector at the exhaust end of the B-pillar detects that the ethylene dichloride content reaches the preset value, the B-pillar is determined to be a saturated resin tank, the exhaust gas enters S23, and the B-pillar enters S3;

[0022] S23, C-pillar-A-pillar tail gas adsorption: the exhaust gas enters the C-pillar and A-pillar in turn for adsorption. The VOCs detector at the exhaust end of the A-pillar monitors the content of ethylene dichloride in the exhaust gas after adsorption in real time. If the content meets the standard, it will be discharged. If the content exceeds the standard, it will re-enter S2;

[0023] When the VOCs detector at the exhaust end of the C-pillar detects that the ethylene dichloride content reaches the preset value, the C-pillar is determined to be a saturated resin tank, the exhaust gas enters S21, and the C-pillar enters S3;

[0024] S3, resin desorption:

[0025] S31, nitrogen replacement: connect the nitrogen tank with the saturated resin tank, and blow the nitrogen into the condensation assembly from the saturated resin tank and the gas in the pipeline. The gas enters the oil-water separator after liquefaction. The oil in the liquid is the dichloroethane condensate, which is separated into the solvent tank. The condensate is collected in the receiving tank, and the non-condensable gas enters S2;

[0026] S32, steam analysis: close the nitrogen tank, start the temperature reduction and pressure reduction device, pass low-pressure steam into the saturated resin tank, the low-pressure steam dissolves the ethylene dichloride, and enters the oil-water separator after liquefaction through the condensation component. The oil in the liquid is the ethylene dichloride condensate and is separated into the solvent tank. The condensate is collected in the receiving tank until the VOCs detector at the output end of the condensation component detects that the ethylene dichloride concentration in the passing liquid is lower than the preset value and then closes the temperature reduction and pressure reduction device;

[0027] S33, spray cooling: if there is water in the condensation tank, pump the water into the saturated resin tank; if there is no water in the condensation tank, pump tap water into the saturated resin tank. The liquid passes through the condensation assembly and enters the condensation tank to be collected. When the temperature of the saturated resin tank drops to room temperature, stop pumping water.

[0028] S34, nitrogen purge: open the nitrogen tank, pump nitrogen into the saturated resin tank, the nitrogen carries water vapor into the condensation assembly, the condensed water enters the condensation tank and is collected, the nitrogen returns to the nitrogen tank, until the surface of the resin material is dried, stop inputting nitrogen, and the desorption of the saturated resin tank is completed;

[0029] S4, wastewater adsorption: when the amount of water in the receiving tank reaches the preset value, the water in the receiving tank is pumped into the resin tank D column, the adsorbed liquid enters the condensation assembly, and is discharged into the condensate tank after cooling. The VOCs detector at the outlet end of the resin tank D column detects the concentration of dichloroethane in the liquid after adsorption. When the concentration is greater than the preset value, the resin tank D column is determined to be a saturated resin tank, S4 is stopped, and the resin tank D column enters S3.

[0030] Furthermore, the sewage generated in the water washing tower 1 and the urea spraying tower is discharged to the sewage treatment system at a regular time, and tap water is added to the water washing tower 1, and the urea water in the urea water replenishing tank is added to the urea spraying tower;

[0031] The pH value in the alkali washing tower is measured. When the pH value is lower than the preset value, the sodium salt solution is discharged into the sewage treatment system, and the washing water in the corresponding rear-end alkali washing tower is added to the front-end alkali washing tower, and the washing water in the second washing tower is combined with the alkaline water in the alkaline water replenishment tank to be added to the last alkali washing tower.

[0032] The advantages of the present invention are:

[0033] 1. Several alkali washing towers are set in the pretreatment component to remove acid from the tail gas multiple times, which can ensure the pH value of the tail gas and avoid corrosion of the rear pipelines and equipment. Water washing towers are set at the beginning and end of the pretreatment, which improves the purity of the reaction gas generated in each process and improves the treatment efficiency and effect of the tail gas;

[0034] 2. An additional resin tank D column is provided. The collection component stores a dichloroethane solution with a certain concentration generated in the resin desorption process. The resin tank D column can perform secondary adsorption on the solution, reduce the dichloroethane content in the condensate, increase the collection rate of dichloroethane, and reduce the pressure of subsequent wastewater treatment;

[0035] 3. A condensate tank is provided to collect low-concentration wastewater generated during the tail gas adsorption process. This part of the wastewater can be introduced into the previous process as spray water in the resin desorption process, or as make-up water for the second water washing tower, that is, the products in the treatment process can be graded, which improves the collection rate and resource utilization rate, and promotes cost reduction and efficiency improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0037] Figure 2 for Figure 1 The front view shown;

[0038] Figure 3 for Figure 1 The top view shown;

[0039] Figure 4 for Figure 1 Left side view shown;

[0040] Figure 5 It is the PID principle diagram of the present invention;

[0041] Figure 6 is the overall process flow chart of tail gas adsorption of the present invention;

[0042] Figure 7 It is the pre-processing PID principle diagram of the present invention;

[0043] Figure 8 This is the A-pillar-B-pillar tail gas adsorption PID principle diagram;

[0044] Fig. 9 This is a process flow chart of resin desorption;

[0045] Fig.10 This is the C-column nitrogen replacement PID principle diagram;

[0046] Fig.11 This is the PID schematic diagram of C column steam analysis;

[0047] Fig.12 This is the PID principle diagram of the C-pillar spray cooling;

[0048] Fig.13 This is the PID schematic diagram of nitrogen purge for C column;

[0049] Fig.14 This is the PID principle diagram of wastewater adsorption on D column;

[0050] In the figure: 1. Pretreatment component; 11. Water washing tower 1; 12. Urea spray tower; 121. Urea water replenishing tank; 13. Alkaline washing tower; 131. Alkaline water replenishing tank; 14. Water washing tower 2; 2. Resin tank group; 21. A column; 22. B column; 23. C column; 3. Resin tank D column; 4. Cooling and pressure reduction device; 5. Nitrogen tank; 6. Condensation component; 61. Condenser 1; 62. Condenser 2; 7. Collection component; 71. Oil-water separator; 72. Solvent tank; 73. Receiving tank; 8. Condensate tank; 9. VOCs detector. DETAILED DESCRIPTION

[0051] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0052] See also Figure 1-5 , the present invention provides the following technical solutions:

[0053] A dichloroethane tail gas adsorption device comprises a pretreatment component 1, wherein the pretreatment component 1 comprises a water scrubber 11, wherein the air inlet end of the water scrubber 11 is the air inlet end of the pretreatment component 1, and the output end of the water scrubber 11 is sequentially connected to a urea spray tower 12, a plurality of alkali scrubbers 13 and a water scrubber 2 14, wherein the output end of the water scrubber 2 14 is the output end of the pretreatment component 1. When the tail gas enters the pretreatment component 1, useless components and solid particles in the gas are first filtered out in the water scrubber 11. Most industrial tail gas has a high temperature, and the water scrubber 11 also has a certain cooling function. Cooling the gas can reduce its corrosion to the pipe wall and extend the life of the device.

[0054] When the tail gas passes through the urea spray tower 12, the nitrogen oxides in the tail gas react with urea and are converted into harmless nitrogen and water;

[0055] The tail gas passes through several alkali washing towers 13, and the acidic substances (acidic gases such as nitric acid mist, hydrogen chloride, and sulfur dioxide) therein are removed by neutralization reaction to form a mixed solution of sodium nitrate, sodium chloride, sodium sulfate, etc. The tail gas passing through the alkali washing tower 13 becomes a neutral gas, and then the water-soluble and solid particles generated in the previous sequence are adsorbed by the water washing tower 2 to ensure the purity of the gas after pretreatment;

[0056] The neutralization reaction of gas is slower than that of solid and liquid. The multiple groups of alkali washing towers 13 are set up to improve the removal rate of acidic substances in the gas by extending the reaction path. Water washing towers are set before and after the alkali washing, which can timely remove the initial exhaust gas and the dust particles and water-soluble impurities carried after the neutralization reaction, thereby improving the purity of the gas and the reaction efficiency.

[0057] The output end of the water washing tower 14 is connected to the resin tank group 2, and the resin tank group 2 is provided with two output ends. One output end of the resin tank group 2 is an exhaust end, and the exhaust end can be communicated with the outside or connected to the air inlet end of the resin tank group 2. When the adsorbed gas meets the emission standards, the gas is discharged. If the adsorbed gas does not meet the emission standards, it re-enters the resin tank group 2 for adsorption treatment to ensure that the treated gas does not cause pollution to the environment.

[0058] The other output end of the resin tank group 2 is connected to a condensation component 6, and the output end of the condensation component 6 is connected in parallel with a collection component 7 and a condensation tank 8. The collection component 7 is connected to a resin tank D column 3, and the output end of the resin tank D column 3 is connected to the condensation component 6. The desorption component is connected to the air inlet end of the resin tank group 2 and the resin tank D column 3. When the desorption component desorbs the resin tank, a nitrogen mixture and a steam mixture containing dichloroethane of different concentrations are generated. The mixture passes through the condensation component 6, and the nitrogen that is not liquefied re-enters the resin tank group 2 for adsorption and then discharge. The dichloroethane and steam are liquefied, and the condensate is packaged according to the concentration of dichloroethane in the condensate. The higher concentration enters the collection component 7, and the lower concentration enters the condensation tank 8. The high-concentration condensate can be further processed later, and the low-concentration condensate can be introduced into the previous process for repeated utilization, thereby improving the adsorption rate and resource utilization, reducing costs and increasing efficiency.

[0059] The exhaust end and the output end of the condensation component 6 are both provided with a VOCs detector 9, which can monitor the dichloroethane concentration of the fluid in the pipeline in real time, so that the system can regulate the process flow.

[0060] The collecting component 7 includes an oil-water separator 71, the input end of the oil-water separator 71 is connected to the output end of the condensing component 6, the oil output end of the oil-water separator 71 is connected to a solvent tank 72, the solvent tank 72 collects and outputs the dichloroethane condensate, and the condensate output end of the oil-water separator 71 is connected to a receiving tank 73. The adsorbent after adsorption saturation is regenerated by low-pressure steam, and the regenerated gas is liquefied after passing through the condensing component 6 and enters the oil-water separator 71. The oil-water separator 71 transfers the dichloroethane oil layer to the solvent tank 72 for subsequent use or treatment, and the oil-water separator 71 transfers the remaining water layer to the receiving tank 73;

[0061] At room temperature, the solubility of ethylene dichloride in water is 0.869%, and its COD is ≥8690ppm. Therefore, the concentration of ethylene dichloride solution in the receiving tank 73 is relatively high and cannot be directly discharged or reused. The receiving tank 73 is connected to the input end of the resin tank D column 3, and the water stored in the receiving tank 73 is pumped to the resin tank D column 3, so that the water stored in the receiving tank 73 can be directly adsorbed. The treated liquid generally has a concentration lower than 100ppm and is low-concentration condensed water, which is collected in the condensed water tank 8. If the concentration is higher than the preset value, the condensed water is returned to the receiving tank 73, and the resin tank D column 3 is desorbed to ensure the adsorption efficiency. The resin tank D column 3 is used to adsorb wastewater, thereby improving the collection rate of ethylene dichloride, reducing the content of compounds in the sewage discharged into the sewage treatment system, and reducing the pressure of sewage treatment.

[0062] The resin tank group 2 includes an A-pillar 21, a B-pillar 22 and a C-pillar 23. The exhaust ends of the A-pillar 21, the B-pillar 22 and the C-pillar 23 are all provided with VOCs detectors 9. After the detection value of a VOCs detector 9 reaches a preset value, the VOCs detector 9 corresponds to a saturated resin tank, the saturated resin tank is disconnected from the pretreatment component 1 and connected to the desorption component, and the other two resin tanks are connected in series and connected to the output end of the pretreatment component 1. The resin tank group 2 adopts a two-absorption and one-standby mode of a commonly used process to ensure the adsorption rate while facilitating desorption, so that the equipment can maintain continuous operation.

[0063] The desorption component includes a temperature reduction and pressure reduction device 4 and a nitrogen tank 5 connected in parallel. The temperature reduction and pressure reduction device 4 can input low-pressure steam. The condensation component 6 includes a condenser 1 61 and a condenser 2 62 connected in series. A fan is connected in series in the gas delivery pipeline, and a water pump is connected in series in the liquid delivery pipeline. The overall device realizes the selection of different processes by opening and closing various fans, water pumps and valves.

[0064] The water inlet of the water washing tower 11 is connected to the external water source, and the urea spray tower 12 is connected to the urea water replenishing tank 121. The water washing tower 11 and the urea spray tower 12 are both set to change water regularly, and the waste water is discharged into the sewage treatment system, and new water is introduced into the water washing tower 11 through tap water;

[0065] The water inlet end of the front alkali washing tower 13 is connected to the drainage end of the adjacent rear alkali washing tower 13, the water inlet end of the last alkali washing tower 13 is connected to the alkali water replenishing tank 131, the water inlet end of the last alkali washing tower 13 is connected to the drainage end of the second water washing tower 14, the water inlet end of the second water washing tower 14 is connected to the condensation tank 8, the low concentration solution in the condensation tank 8 can be introduced into the last alkali washing tower 13 by a water pump, and the alkali washing tower 13 is replenished with water in cooperation with the alkali water replenishing tank 131. The urea spray tower 12 and the alkali washing tower 13 are both provided with a pH meter, which can monitor the pH value in the tower in real time. When the pH value is lower than the preset value, the water replenishment operation is performed. When several alkali washing towers 13 are replaced with water, the washing water in the front tower is discharged into the sewage treatment system, and then the washing water in the adjacent towers at the rear is introduced into the front tower in turn. The washing water in the second water washing tower 14 can be used as the replenishment water of the last alkali washing tower 13, and the condensation tank 8 can replenish the second water washing tower 14;

[0066] The output end of the condensation tank 8 is connected to the spray ports of the resin tank group 2 and the resin tank D column 3. The water stored in the condensation tank 8 can also be used as the spray water required for desorption of the resin tank group 2 and the resin tank D column 3.

[0067] Differentiating reaction products of different concentrations and storing them separately facilitates their reprocessing and reuse, which improves the overall adsorption rate of the device. A highly integrated system is set up to rationally allocate the use of resources, improve resource utilization, reduce finished products, and reduce the pressure of subsequent processing, thereby achieving cost reduction and efficiency improvement.

[0068] See also Figure 6-14 , a dichloroethane tail gas adsorption method using the above device:

[0069] S1, pretreatment: the waste gas is introduced into the pretreatment component 1, and is successively passed through the water scrubber 11, the urea spray tower 12, several alkali scrubbers 13 and the water scrubber 2 14, and then output as neutral gas;

[0070] S2, exhaust gas enters resin tank group 2;

[0071] S21, A-pillar-B-pillar tail gas adsorption: the exhaust gas enters the A-pillar 21 and the B-pillar 22 in turn for adsorption, and the VOCs detector 9 at the exhaust end of the B-pillar 22 monitors the content of ethylene dichloride in the exhaust gas after adsorption in real time. If the content meets the standard, it is discharged. If the content exceeds the standard, it re-enters S2;

[0072] When the VOCs detector 9 at the exhaust end of the A-pillar 21 detects that the ethylene dichloride content reaches a preset value, the A-pillar 21 is determined to be a saturated resin tank, the exhaust gas enters S22, and the A-pillar 21 enters S3;

[0073] S22, B-pillar-C-pillar tail gas adsorption: the exhaust gas enters the B-pillar 22 and the C-pillar 23 in turn for adsorption, and the VOCs detector 9 at the exhaust end of the C-pillar 23 monitors the content of dichloroethane in the exhaust gas after adsorption in real time. If the content meets the standard, it will be discharged. If the content exceeds the standard, it will re-enter S2;

[0074] When the VOCs detector 9 at the exhaust end of the B-pillar 22 detects that the ethylene dichloride content reaches a preset value, the B-pillar 22 is determined to be a saturated resin tank, the exhaust gas enters S23, and the B-pillar 22 enters S3;

[0075] S23, C-pillar-A-pillar tail gas adsorption: the exhaust gas enters the C-pillar 23 and the A-pillar 21 in turn for adsorption, and the VOCs detector 9 at the exhaust end of the A-pillar 21 monitors the content of ethylene dichloride in the exhaust gas after adsorption in real time. If the content meets the standard, it will be discharged. If the content exceeds the standard, it will re-enter S2;

[0076] When the VOCs detector 9 at the exhaust end of the C-pillar 23 detects that the dichloroethane content reaches a preset value, the C-pillar 23 is determined to be a saturated resin tank, the exhaust gas enters S21, and the C-pillar 23 enters S3;

[0077] S3, resin desorption:

[0078] S31, nitrogen replacement: connect the nitrogen tank 5 with the saturated resin tank, and blow the nitrogen into the condensation assembly 6 from the saturated resin tank and the gas in the pipeline. The gas enters the oil-water separator 71 after liquefaction. The oil in the liquid is the dichloroethane condensate which is separated into the solvent tank 72. The condensate is collected in the receiving tank 73, and the non-condensable gas enters S2;

[0079] S32, steam analysis: close the nitrogen tank 5, start the temperature reduction and pressure reduction device 4, pass low-pressure steam into the saturated resin tank, the low-pressure steam dissolves the ethylene dichloride, and enters the oil-water separator 71 after liquefaction through the condensation component 6. The oil in the liquid is the ethylene dichloride condensate, which is separated into the solvent tank 72, and the condensate is collected in the receiving tank 73 until the VOCs detector 9 at the output end of the condensation component 6 detects that the ethylene dichloride concentration in the liquid passing through is lower than the preset value, and then closes the temperature reduction and pressure reduction device 4;

[0080] S33, spray cooling: if there is water in the condensation tank 8, pump the water into the saturated resin tank; if there is no water in the condensation tank 8, pump tap water into the saturated resin tank, and the liquid enters the condensation tank 8 after passing through the condensation assembly 6 and is collected. When the temperature of the saturated resin tank drops to room temperature, stop pumping water;

[0081] S34, nitrogen purge: open the nitrogen tank 5, pump nitrogen into the saturated resin tank, the nitrogen carries water vapor into the condensation assembly 6, the condensed water enters the condensation tank 8 to be collected, the nitrogen returns to the nitrogen tank 5, until the surface of the resin material is dried, stop inputting nitrogen, and the desorption of the saturated resin tank is completed;

[0082] S4, wastewater adsorption: when the amount of water stored in the receiving tank 73 reaches the preset value, the water stored in the receiving tank 73 is pumped into the resin tank D column 3, and the adsorbed liquid enters the condensation component 6, and is discharged into the condensation tank 8 after cooling. The VOCs detector 9 at the outlet end of the resin tank D column 3 detects the concentration of dichloroethane in the liquid after adsorption. When the concentration is greater than the preset value, the resin tank D column 3 is determined to be a saturated resin tank, S4 is stopped, and the resin tank D column 3 enters S3.

[0083] The wastewater generated in the water washing tower 11 and the urea spraying tower 12 is discharged to the wastewater treatment system at regular intervals, and tap water is added to the water washing tower 11, and the urea water in the urea water replenishing tank 121 is added to the urea spraying tower 12;

[0084] The pH value in the alkali washing tower 13 is measured. When the pH value is lower than the preset value, the sodium salt solution is discharged into the sewage treatment system, and the washing water in the corresponding rear-end alkali washing tower 13 is added to the front-end alkali washing tower 13, and the washing water in the water washing tower 2 14 is combined with the alkaline water in the alkaline water replenishment tank 131 to be added to the last alkali washing tower 13.

[0085] In summary, the pretreatment component 1 is provided with a plurality of alkali washing towers 13, which perform multiple acid removal on the tail gas, thereby ensuring the pH value of the tail gas and avoiding corrosion of the rear pipelines and equipment. In addition, water washing towers are provided at the beginning and end of the pretreatment, thereby improving the purity of the reaction gas generated in each process and improving the treatment efficiency and effect of the tail gas.

[0086] An additional resin tank D column 3 is provided, and a dichloroethane solution with a certain concentration generated in the resin desorption process is stored in the collecting component 7. The resin tank D column 3 can perform secondary adsorption on the solution, thereby reducing the dichloroethane content in the condensate, increasing the collection rate of dichloroethane, and reducing the pressure of subsequent wastewater treatment;

[0087] A condensate tank 8 is provided to collect low-concentration wastewater generated during the exhaust gas adsorption process. This part of the wastewater can be introduced into the previous process for use as spray water in the resin desorption process, or as make-up water for the water washing tower 14, that is, the products in the treatment process can be graded, thereby improving the collection rate and resource utilization rate, and promoting cost reduction and efficiency improvement.

[0088] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0089] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

Claims

1. A dichloroethane tail gas adsorption device, comprising a pretreatment component (1), wherein the output end of the pretreatment component (1) is connected to a resin tank group (2), characterized in that: The resin tank group (2) is provided with two output ends, one of which is an exhaust end, which can be communicated with the outside or connected to the air inlet end of the resin tank group (2), and the other output end of the resin tank group (2) is connected to a condensation component (6), and the output end of the condensation component (6) is connected in parallel with a collection component (7) and a condensation tank (8), and the collection component (7) is connected to a resin tank D column (3), and the output end of the resin tank D column (3) is connected to the condensation component (6), and the air inlet end of the resin tank group (2) and the resin tank D column (3) is connected to a desorption component, and the exhaust end and the output end of the condensation component (6) are both provided with a VOCs detector (9), and the output end of the condensation tank (8) is both connected to the spray ports of the resin tank group (2) and the resin tank D column (3), and the output end of the condensation tank (8) is connected to the pretreatment component (1).

2. The ethylene dichloride tail gas adsorption device according to claim 1, characterized in that: The pretreatment component (1) comprises a water washing tower (11), the air inlet end of the water washing tower (11) is the air inlet end of the pretreatment component (1), the output end of the water washing tower (11) is connected to a urea spray tower (12), a plurality of alkali washing towers (13) and a water washing tower (14) in sequence, the water inlet end of the water washing tower (11) is connected to an external water source, the urea spray tower (12) is connected to a urea water replenishing tank (121), and the front end The water inlet end of the alkali washing tower (13) is connected to the drainage end of the alkali washing tower (13) adjacent to it at the rear end; the water inlet end of the last alkali washing tower (13) is connected to an alkali water replenishing tank (131); the water inlet end of the last alkali washing tower (13) is connected to the drainage end of the second water washing tower (14); the water inlet end of the second water washing tower (14) is connected to a condensation tank (8); and the output end of the second water washing tower (14) is the output end of the pretreatment component (1).

3. The ethylene dichloride tail gas adsorption device according to claim 2, characterized in that: The collecting component (7) comprises an oil-water separator (71), the input end of the oil-water separator (71) is connected to the output end of the condensing component (6), the oil output end of the oil-water separator (71) is connected to a solvent tank (72), the solvent tank (72) collects and outputs dichloroethane condensate, the condensate output end of the oil-water separator (71) is connected to a receiving tank (73), the receiving tank (73) collects an aqueous solution containing dichloroethane, and the receiving tank (73) is connected to the input end of the resin tank D column (3).

4. The ethylene dichloride tail gas adsorption device according to claim 3, characterized in that: The desorption component comprises a temperature reduction and pressure reduction device (4) and a nitrogen tank (5) connected in parallel to each other, the temperature reduction and pressure reduction device (4) can be input with low-pressure steam, and the condensation component (6) comprises a condenser 1 (61) and a condenser 2 (62) connected in series.

5. The ethylene dichloride tail gas adsorption device according to claim 4, characterized in that: The resin tank group (2) comprises an A column (21), a B column (22) and a C column (23); exhaust ends of the A column (21), the B column (22) and the C column (23) are all provided with a VOCs detector (9); after the detection value of one of the VOCs detectors (9) reaches a preset value, the VOCs detector (9) corresponds to a saturated resin tank, the saturated resin tank is disconnected from the pretreatment component (1) and connected to the desorption component; the other two resin tanks are connected in series and communicated with the output end of the pretreatment component (1).

6. The ethylene dichloride tail gas adsorption device according to claim 5, characterized in that: The pipeline connecting the above components is used to transport gas, and the pipeline connecting the above components is used to transport liquid, and the gas pipeline is connected in series with a fan, and the liquid pipeline is connected in series with a water pump.

7. A method for adsorbing ethylene dichloride tail gas, characterized in that: The dichloroethane tail gas adsorption device according to any one of claims 1 to 6 comprises the following steps: S1, pretreatment: the waste gas is introduced into the pretreatment component (1), and is sequentially passed through a water scrubber 1 (11), a urea spray tower (12), a plurality of alkali scrubbers (13) and a water scrubber 2 (14), and then output as neutral gas; S2, the waste gas enters the resin tank group (2); S21, A-pillar-B-pillar tail gas adsorption: the exhaust gas enters the A-pillar (21) and the B-pillar (22) in sequence for adsorption, and the VOCs detector (9) at the exhaust end of the B-pillar (22) monitors the content of dichloroethane in the exhaust gas after adsorption in real time. If the content meets the standard, it is discharged; if the content exceeds the standard, it re-enters S2; When the VOCs detector (9) at the exhaust end of the A column (21) detects that the ethylene dichloride content reaches a preset value, the A column (21) is determined to be a saturated resin tank, the exhaust gas enters S22, and the A column (21) enters S3; S22, B-pillar-C-pillar tail gas adsorption: the exhaust gas enters the B-pillar (22) and C-pillar (23) in sequence for adsorption, and the VOCs detector (9) at the exhaust end of the C-pillar (23) monitors the content of dichloroethane in the exhaust gas after adsorption in real time. If the content meets the standard, it is discharged; if the content exceeds the standard, it re-enters S2; When the VOCs detector (9) at the exhaust end of the B-pillar (22) detects that the ethylene dichloride content reaches a preset value, the B-pillar (22) is determined to be a saturated resin tank, the exhaust gas enters S23, and the B-pillar (22) enters S3; S23, C-pillar-A-pillar tail gas adsorption: the exhaust gas enters the C-pillar (23) and the A-pillar (21) in sequence for adsorption, and the VOCs detector (9) at the exhaust end of the A-pillar (21) monitors the content of dichloroethane in the exhaust gas after adsorption in real time. If the content meets the standard, it is discharged; if the content exceeds the standard, it re-enters S2; When the VOCs detector (9) at the exhaust end of the C column (23) detects that the dichloroethane content reaches a preset value, the C column (23) is determined to be a saturated resin tank, the exhaust gas enters S21, and the C column (23) enters S3; S3, resin desorption: S31, nitrogen replacement: connect the nitrogen tank (5) with the saturated resin tank, blow the nitrogen into the saturated resin tank and the gas in the pipeline into the condensation assembly (6), the gas is liquefied and enters the oil-water separator (71), the oil in the liquid is the dichloroethane condensate and is separated into the solvent tank (72), the condensate is collected in the receiving tank (73), and the non-condensable gas enters S2; S32, steam analysis: close the nitrogen tank (5), start the temperature reduction and pressure reduction device (4), pass low-pressure steam into the saturated resin tank, the low-pressure steam dissolves the ethylene dichloride, passes through the condensation component (6) and is liquefied before entering the oil-water separator (71), the oil in the liquid is the ethylene dichloride condensate which is separated into the solvent tank (72), and the condensate is collected in the receiving tank (73), until the VOCs detector (9) at the output end of the condensation component (6) detects that the ethylene dichloride concentration in the passing liquid is lower than the preset value, and then closes the temperature reduction and pressure reduction device (4); S33, spray cooling: if there is water in the condensation tank (8), the water is pumped into the saturated resin tank; if there is no water in the condensation tank (8), tap water is pumped into the saturated resin tank. The liquid passes through the condensation assembly (6) and enters the condensation tank (8) to be collected. When the temperature of the saturated resin tank drops to room temperature, the pumping is stopped; S34, nitrogen purge: open the nitrogen tank (5), pump nitrogen into the saturated resin tank, and the nitrogen carries water vapor into the condensation component (6), and the condensed water enters the condensation tank (8) to be collected, and the nitrogen returns to the nitrogen tank (5) until the surface of the resin material is dried, and stop inputting nitrogen. At this time, the desorption of the saturated resin tank is completed; S4, wastewater adsorption: when the amount of water stored in the receiving tank (73) reaches a preset value, the water stored in the receiving tank (73) is pumped into the resin tank D column (3), and the adsorbed liquid enters the condensation component (6), and is discharged into the condensation tank (8) after cooling. The VOCs detector (9) at the outlet end of the resin tank D column (3) detects the concentration of dichloroethane in the adsorbed liquid. When the concentration is greater than the preset value, the resin tank D column (3) is determined to be a saturated resin tank, and S4 is stopped, and the resin tank D column (3) enters S3.

8. The method for adsorbing ethylene dichloride tail gas according to claim 7, characterized in that: The sewage generated in the water washing tower (11) and the urea spraying tower (12) is discharged to the sewage treatment system at regular intervals, tap water is added to the water washing tower (11), and urea water in the urea water replenishing tank (121) is added to the urea spraying tower (12); The pH value in the alkali washing tower (13) is measured, and when the pH value is lower than a preset value, the sodium salt solution is discharged into the sewage treatment system, and the washing water in the corresponding rear-end alkali washing tower (13) is supplemented into the front-end alkali washing tower (13), and the washing water in the second water washing tower (14) and the alkaline water in the alkaline water supplement tank (131) are supplemented into the last alkali washing tower (13).

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