VOCs tail gas treatment equipment for coal gas purification system of coking plant

Abstract

The invention discloses VOCs tail gas treatment equipment for a coal gas purification system of a coking plant, and belongs to the technical field of tail gas treatment. Comprising an activated carbon adsorption tower, an exhaust funnel and a combustion box spray tower, a spraying mechanism is mounted at the upper end of the spraying tower, and a circulating mechanism is mounted at the lower end; a desorption mechanism is mounted between the activated carbon adsorption tower and the combustion box, and impurities on an adsorption carbon layer in the activated carbon adsorption tower are discharged into the combustion box for treatment through the desorption mechanism when the adsorption capacity of the activated carbon adsorption tower reaches a threshold value; the desorption mechanism comprises an upper desorption cylinder and a lower desorption cylinder, one end of the upper desorption cylinder is connected with a cooling assembly, and a recovery assembly is installed between the combustion box and the upper desorption cylinder; the primary purification effect is improved, the treatment efficiency is improved, and the problems that an existing device is poor in primary adsorption effect, turbine fan blades are prone to adsorbing particulate matter and blocking, the water consumption is large, the energy consumption is high, and shutdown cooling is needed are solved.

Description

Technical Field

[0001] This invention belongs to the field of exhaust gas treatment technology, specifically a VOCs exhaust gas treatment device for a coking plant coal gas purification system. Background Technology

[0002] During the coal gas purification process in coking plants, exhaust gases containing large amounts of VOCs, dust, and acid mist are generated. These exhaust gases have complex compositions and high pollutant concentrations; direct emission would cause serious air pollution and negatively impact the working environment at the production site. Therefore, they must be purified to meet emission standards using specialized treatment equipment. Currently, the industry commonly uses a combination of spray tower, activated carbon adsorption, and catalytic combustion for VOCs exhaust gas treatment in coking plant coal gas purification systems. However, existing equipment still suffers from numerous technical shortcomings in practical applications due to limitations in structural design and process coordination. The treatment effect, operating costs, and operational stability are insufficient to meet the industrial production needs of coking plants. Specific problems include: First, existing spray towers mostly use a single spray structure, resulting in short contact time and insufficient mixing between the exhaust gas and the spray liquid, limiting their effectiveness in adsorbing and removing water-soluble pollutants such as dust and acid mist. Furthermore, the airflow inside the tower is vertical, causing particulate matter to easily agglomerate and escape with the airflow, hindering efficient pretreatment and increasing the load on downstream activated carbon adsorption and combustion equipment. Some spray towers have swirling or stirring moving parts that easily adsorb particulate matter from the exhaust gas, forming scale and clogging, which not only reduces the swirling effect but also causes component jamming and reduced rotational speed. Moreover, current cleaning methods mostly involve manual disassembly and cleaning, which is cumbersome and requires shutdown, severely impacting the continuity of exhaust gas treatment. Second, the spray liquid in spray towers is mostly for single use or simply filtered and then recycled, without deep treatment of the wastewater composition, resulting in low wastewater reuse rates and high water consumption during production. Additionally, dedicated [equipment / facilities] are not provided. The waste liquid recovery and purification structure suffers from secondary pollution due to direct discharge of wastewater, increasing environmental treatment costs. Furthermore, the heating layers of the catalytic combustion and direct combustion chambers require continuous high-power operation to heat and burn the desorbed waste gas, resulting in the direct emission of a large amount of waste heat without recovery. The lack of a heat recovery linkage between the activated carbon adsorption tower and the combustion chamber leads to significant energy waste and increases the operating costs of tail gas treatment. During desorption, the activated carbon adsorption tower is prone to continuous temperature increases due to the reflux of waste heat from the combustion chamber and the desorption reaction. If the temperature exceeds the activated carbon's tolerance threshold, it can lead to activated carbon deactivation, a sharp drop in adsorption efficiency, and even safety hazards. Current cooling methods often involve air or water cooling after shutdown, requiring the removal of some components for operation, which not only interrupts the tail gas treatment process but also increases manual labor intensity. Therefore, improvements are needed to address these issues. Summary of the Invention

[0003] This invention overcomes the shortcomings of the prior art and proposes a VOCs tail gas treatment device for a coking plant gas purification system; it solves the problems of poor initial adsorption effect, easy adsorption of particulate matter and clogging of turbine fan blades, large water consumption, high energy consumption and the need for shutdown for cooling in existing devices.

[0004] This invention is achieved through the following technical solution: A VOCs tail gas treatment device for a coking plant gas purification system includes an activated carbon adsorption tower, an exhaust stack located on one side of the activated carbon adsorption tower, a combustion chamber located between the exhaust stack and the activated carbon adsorption tower, and a spray tower located on the other side of the activated carbon adsorption tower. A spraying mechanism for preliminary adsorption of the tail gas is installed at the upper end of the spray tower, and a circulation mechanism for reducing the spray water consumption is installed at the lower end of the spray tower. The output end of the spray tower is connected to the activated carbon adsorption tower. A desorption mechanism is installed between the activated carbon adsorption tower and the combustion chamber. When the adsorption capacity of the activated carbon adsorption tower reaches the threshold, the impurities on the adsorbed carbon layer in the activated carbon adsorption tower are discharged into the combustion chamber for treatment. The desorption mechanism includes an upper desorption cylinder and a lower desorption cylinder installed at the upper and lower ends of the activated carbon adsorption tower, respectively. The end of the lower desorption cylinder away from the activated carbon adsorption tower is connected to a third fan, which is connected to the inside of the combustion chamber. A cooling component is connected to one end of the upper desorption cylinder. A recovery component is installed between the combustion chamber and the upper desorption cylinder. Solenoid valves are installed at the connection points between the upper and lower desorption cylinders and the activated carbon adsorption tower.

[0005] Furthermore, the circulation mechanism includes a waste liquid recovery layer located at the bottom of the spray tower. An anti-clogging grid is installed on the top of the waste liquid recovery layer, and a conical guide slope is provided at the top of the anti-clogging grid. An electrolytic cell is separated from one corner of the waste liquid recovery layer by a partition. An electrolytic cell is installed with an electrolyzer. One end of the electrolyzer is equipped with a micro water pump that draws the wastewater in the waste liquid recovery layer into the electrolyzer for electrolytic separation. A pressurized water pump is installed on one side of the spray tower. One end of the pressurized water pump is connected to the inside of the electrolytic cell, and the other end of the pressurized water pump is divided into a first branch pipe and a second branch pipe. The first branch pipe is connected to a distributor, and the second branch pipe is connected to the spray mechanism.

[0006] Furthermore, the spraying mechanism includes multiple cyclones installed directly above the waste liquid recovery layer. A humidification layer is installed at the upper end of the cyclones, and a turbulent water pipe is installed at the upper end of the humidification layer. Multiple branch pipes corresponding to the multiple cyclones are branched off from the turbulent water pipes. Each branch pipe is equipped with a downward spray head, and the turbulent water pipe is connected to a second branch pipe. A demister is installed at the upper end of the turbulent water pipe.

[0007] Furthermore, a turbulence ring is installed inside the cyclone. Both ends of the turbulence ring are horn-shaped. A turbine blade is rotatably connected inside the turbulence ring via a cross mounting bracket. A pressurized water pipe is installed on the cross mounting bracket. A high-pressure nozzle facing the turbine blade is installed at one end of the pressurized water pipe, and the other end of the pressurized water pipe is connected to a distributor.

[0008] Furthermore, a dry filter is connected to the output end of the spray tower via a first fan, and the dry filter is connected to the activated carbon adsorption tower.

[0009] Furthermore, the dry filter has two layers of straight filter screens installed inside, with a pleated filter screen installed between the two layers of straight filter screens. A double-opening sealed door is hinged on one side of the dry filter, and a limit lock is installed on the double-opening sealed door. The dry filter is connected to the activated carbon adsorption tower through a fire damper.

[0010] Furthermore, there are multiple activated carbon adsorption towers, with the upper ends of the multiple activated carbon adsorption towers connected to the same exhaust manifold and the lower ends of the multiple activated carbon adsorption towers connected to the same air inlet manifold; the fire damper is connected to the air inlet manifold at the lower end of the activated carbon adsorption tower; the exhaust manifold is connected to a second fan, the output end of the second fan is connected to the bottom end of the exhaust manifold, and a conical rainproof eaves are installed at the top of the exhaust manifold; solenoid valves are installed at both the upper and lower ends of the activated carbon adsorption tower, and a sealed pull-out cabinet is inserted into the activated carbon adsorption tower, with multiple layers of activated carbon plates placed inside the sealed pull-out cabinet.

[0011] Furthermore, a heating layer is installed at the upper part of the combustion chamber, the air inlet of the combustion chamber is located on one side of the heating layer, a through groove is opened on one side of the bottom plate of the heating layer, and an L-shaped partition plate is fixed to the bottom of the heating layer. An air inlet channel is provided between the partition plate and the inner wall of one side of the combustion chamber. A chemical reaction plate and a combustion layer are installed at the lower end of the heating layer between the partition plate and the inner wall of the other side of the combustion chamber. The combustion layer is located directly below the chemical reaction plate, and the air inlet channel, the chemical reaction plate and the combustion layer are interconnected. A drain outlet is opened in the middle of the combustion chamber, and the drain outlet is adjacent to the chemical reaction plate.

[0012] Furthermore, the recovery component includes an exhaust port located on the combustion chamber between the heating layer and the chemical reaction plate. The exhaust port is connected to a fourth fan, which extracts the gases after the combustion reaction. The output end of the fourth fan is connected to the upper desorption cylinder and the cooling cylinder through ducts. The end of the cooling cylinder away from the duct is connected to the exhaust pipe. A diversion valve is installed at the connection between the upper desorption cylinder and the duct.

[0013] Furthermore, the cooling component includes a liquid nitrogen tank located at the rear end of the upper desorption cylinder and a thermometer installed on the activated carbon adsorption tower. The output end of the liquid nitrogen tank is connected to one end of the upper desorption cylinder, and a solenoid valve is installed at the output end of the liquid nitrogen tank.

[0014] The beneficial effects of this invention compared to the prior art are as follows: 1. This invention, through the combination of a cyclone separator, a turbulence ring, and turbine blades, enables the exhaust gas to form a spiral upward airflow within the cyclone separator, extending the contact time with the spray liquid and improving the initial purification effect. This allows for the initial adsorption of water-soluble harmful gases such as dust and acid mist in the exhaust gas. 2. This invention, through the combination of a high-pressure nozzle and a specially shaped turbine blade, facilitates the humidification of exhaust gas while accelerating the rotation speed of the turbine blade, thereby improving the effect of particulate matter dispersion. At the same time, the high-pressure nozzle can also clean the turbine blade without damaging its surface. 3. This invention, through the cooperation of a pressurized water pump, an electrolytic cell, and a distributor, treats the spray wastewater collected in the waste liquid recovery layer in the electrolytic cell and then transports it back to the spraying mechanism, thereby reducing the amount of water used for spraying, improving the water resource utilization rate, and thus realizing the function of water resource recycling. 4. This invention facilitates the recovery of heat generated in the combustion chamber by combining the recovery component and the cooling component, thereby reducing the power consumption of the combustion chamber. At the same time, the thermometer and liquid nitrogen tank can monitor the temperature inside the activated carbon adsorption tower in real time, and the cooling can be carried out at high temperatures without stopping the machine or disassembling parts, thus improving the processing efficiency. This ultimately solved the problems of poor initial adsorption effect, easy adsorption of particulate matter clogging the turbine blades, high water consumption, high energy consumption, and the need to shut down for cooling in existing devices. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall appearance of the device of the present invention; Figure 2 This is another perspective view of the overall appearance of the device of the present invention; Figure 3 This is a schematic diagram of the spray tower structure of the present invention; Figure 4 This is a schematic cross-sectional view of the spray tower structure of the present invention; Figure 5 This is a schematic diagram of the turbine blade structure of the present invention; Figure 6 This is a schematic diagram of the internal structure of the dry filter of the present invention; Figure 7 This is a schematic diagram of the activated carbon adsorption tower structure of the present invention; Figure 8 This is a schematic diagram of the cooling cylinder structure of the present invention; Figure 9 This is a schematic diagram of the upper and lower desorption cylinders of the present invention; Figure 10 This is a schematic cross-sectional view of the combustion chamber structure of the present invention.

[0016] The diagram shows the following components: 1. Activated carbon adsorption tower; 2. Exhaust stack; 3. Combustion chamber; 4. Spray tower; 5. Fire damper; 6. First fan; 7. Dry filter; 8. Liquid nitrogen tank; 9. Waste liquid recovery layer; 10. Cyclone separator; 11. Humidification layer; 12. Demisting plate; 13. Anti-clogging grille; 14. Electrolytic cell; 15. Pressurized water pump; 16. Diverter; 17. Baffle ring; 18. Turbine fan blade; 19. High-pressure nozzle; 20. 21. Spray head; 22. Straight filter screen; 23. Folded filter screen; 24. Sealed pull-out cabinet; 25. Thermometer; 26. Air inlet outer cylinder; 27. Exhaust outer cylinder; 28. Second fan; 29. ​​Rainproof eaves; 30. Upper desorption cylinder; 31. Lower desorption cylinder; 32. Third fan; 33. Heating layer; 34. Air inlet channel; 35. Chemical reaction plate; 36. Combustion layer; 37. Drain outlet; 38. Fourth fan; 39. Cooling exhaust cylinder. Detailed Implementation

[0017] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0018] See Figures 1 to 10 This embodiment proposes a VOCs tail gas treatment device for a coking plant gas purification system, including multiple activated carbon adsorption towers 1, an exhaust stack 2 located on one side of the multiple activated carbon adsorption towers 1, a combustion chamber 3 located between the exhaust stack 2 and the activated carbon adsorption towers 1, and a spray tower 4 located on the other side of the multiple activated carbon adsorption towers 1. The adsorbent carbon layer in the activated carbon adsorption towers 1 can efficiently capture VOCs, odorous gases, acidic gases, alkaline gases, and some harmful impurities in the exhaust gas, achieving gas purification and compliance with emission standards. The combustion chamber 3 can burn the harmful substances on the adsorbent carbon layer, and then decompose them into water and carbon dioxide through a chemical reaction. The spray tower 4 facilitates the absorption, neutralization, and washing effects of the spray liquid to remove VOCs. The exhaust gas contains dust, acid mist, alkaline mist, water-soluble harmful gases, and some particulate matter. The upper part of the spray tower 4 is equipped with a spray mechanism for preliminary adsorption of the exhaust gas. This mechanism allows for multi-stage adsorption of particulate matter within the harmful gases. The lower part of the spray tower 4 is equipped with a circulation mechanism to reduce water consumption during spraying. This mechanism facilitates the reuse of the used spray liquid after electrolytic purification, reducing water consumption during operation and lowering the cost of exhaust gas treatment. Furthermore, a desorption mechanism is installed between the activated carbon adsorption tower 1 and the combustion chamber 3. This mechanism facilitates the collection and treatment of impurities on the activated carbon layer when the adsorption capacity of the activated carbon adsorption tower 1 reaches a threshold, preventing blockage of the activated carbon plates and ensuring effective purification of the exhaust gas.

[0019] The circulation mechanism includes a waste liquid recovery layer 9 located at the bottom of the spray tower 4. An anti-clogging grille 13 is installed on top of the waste liquid recovery layer 9, with a tapered guide section at the top to prevent wastewater accumulation on its top surface. An electrolysis cell 14 is separated from one corner of the waste liquid recovery layer 9 by a partition. The electrolysis cell 14 can be equipped with electrolyzers of varying power depending on the exhaust gas treatment capacity. A micro-pump draws wastewater from the waste liquid recovery layer 9 into the electrolyzer for electrolysis. The solution is decomposed and converted into reusable spray water. A pressurized water pump 15 is installed on one side of the spray tower 4. The pressurized water pump 15 extracts the decomposed spray liquid and pressurizes it to be transported upward. One end of the pressurized water pump 15 is connected to the inside of the electrolytic cell 14. The other end of the pressurized water pump 15 is divided into a first branch pipe and a second branch pipe. The first branch pipe is connected to a distributor 16, which facilitates the even distribution of the pressurized spray liquid to all the pressurized water pipes. The second branch pipe is connected to the spraying mechanism.

[0020] The spraying mechanism includes multiple cyclone separators 10 installed directly above the waste liquid recovery layer 9. The cyclone separators 10, in conjunction with the suction generated by the first fan 6, drive the exhaust gas upwards. A humidification layer 11 is installed at the upper end of each cyclone separator 10. The humidification layer 11 wets the exhaust gas that has not come into contact with the spray liquid, causing particulate matter to be attracted to the water, thus increasing the weight of the particulate matter and causing it to fall downwards into the waste liquid recovery layer 9. A turbulent water pipe is installed at the upper end of the humidification layer 11. Branch pipes corresponding to the multiple cyclone separators 10 branch off from the turbulent water pipes. Each of the multiple branch pipes is equipped with downward-facing spray heads 20. The turbulent water pipe connects to the second branch pipe, and the spray water is delivered to multiple branch pipes and spray heads 20 through the turbulent water pipe, and then sprayed downwards to combine with the exhaust gas. A demister plate 12 is installed at the upper end of the turbulent water pipe, which facilitates efficient separation of liquid droplets and mist entrained in the exhaust gas, intercepts and removes tiny suspended liquid droplets in the airflow, and thus achieves the effect of gas-liquid separation. Three sets of turbulence rings 17 are installed inside the cyclone 10, each set including two turbulence rings 17 arranged at the top and bottom. The upper and lower ends of the turbulence rings 17 are funnel-shaped, and the turbulence rings decrease in size from large to small. The special structure, from small to large, enhances the dispersion effect of air on particles accumulated in the exhaust gas. Each group of two turbulence rings 17 has turbine blades 18 rotatably connected to its upper and lower parts, as well as between the two rings 17, via a cross-shaped mounting bracket. These turbine blades 18 employ a gradient-angle blade design to prevent excessive local airflow turbulence or insufficient mixing. Simultaneously, the rounded chamfered edges of the blades reduce pressure drop and blade wear caused by airflow impact. A pressurized water pipe is mounted on the cross-shaped mounting bracket, with two sets of high-pressure nozzles facing the turbine blades 18 at one end. 19. The high-pressure nozzle 19 washes the turbine blades 18, which on the one hand allows the water film formed on the surface of the turbine blades 18 to come into contact with the exhaust gas and wet it, and on the other hand, the spray water sprayed by the high-pressure nozzle 19 can also wash off the particulate matter adsorbed on the surface of the turbine blades 18. At the same time, the inertia of the high pressure can also drive the turbine blades 18 to rotate, increasing the speed of the turbine blades 18. Since the turbine blades 18 are always rotating, the spray water will not damage the surface of the turbine blades 18. The other ends of the two pressurized water pipes converge at one end of the distributor 16.

[0021] like Figure 2 , Figure 6 , Figure 7As shown, the output end of the spray tower 4 is connected to a first fan 6 via an assembled air pipe. The first fan 6 generates suction to drive multiple turbine blades 18 to rotate, forming a vortex airflow that carries the exhaust gas upward. A supporting steel frame is installed at the lower end of the first fan 6. A dry filter 7 is connected to the end of the first fan 6 away from the spray tower 4. The dry filter 7 uses a porous filter medium to physically separate solid particles, dust, oil mist, paint mist, and other impurities from the gas, purifying the fluid, protecting downstream equipment, ensuring process and environmental compliance, and preventing secondary pollution. The dry filter 7 has two layers of straight filter screens 21 installed inside, with a pleated filter screen 22 installed between the two layers of straight filter screens 21. The gas passes through the straight filter screens 21 and the pleated filter screen 22. The combination of 2 increases the filtration area; a double-leaf sealing door is hinged on one side of the dry filter 7, and a limit lock is installed on the double-leaf sealing door. With the cooperation of the double-leaf door and the limit lock, the straight filter screen 21 and the folded filter screen 22 inside can be taken out for cleaning after the device is used. At the same time, sealing components such as sealing rings are installed on the double-leaf door to ensure that there is no air leakage during the process; a fire damper 5 is installed at the end of the dry filter 7 away from the first fan 6. The fire damper 5 can be used to close immediately when the activated carbon adsorption tower 1 catches fire at high temperature, blocking the air connection between the dry filter 7 and the activated carbon adsorption tower 1, and avoiding high temperature damage to the straight filter screen 21 and the folded filter screen 22 inside the dry filter 7.

[0022] Multiple activated carbon adsorption towers 1 are connected to the same exhaust manifold 26 at their upper ends and to the same air inlet manifold 25 at their lower ends. The air inlet manifold 25 is connected to a fire damper 5 and draws the waste gas filtered by the dry filter 7 from bottom to top into the activated carbon adsorption tower 1. Then, the exhaust manifold 26, in conjunction with a second fan 27, generates suction to draw the filtered air to the exhaust manifold 2 for discharge. The exhaust manifold 26 is connected to the second fan 27, the output end of which is connected to the bottom of the exhaust manifold 2. A conical rainproof eaves 28 are installed at the top of the exhaust manifold 2 to prevent rainwater from entering the second fan 27 and damaging it during rainy weather. Solenoid valves are installed at both the upper and lower ends of the activated carbon adsorption tower 1. The multiple activated carbon adsorption towers 1 are not activated simultaneously. For example, when the first two activated carbon adsorption towers 1 are in operation, the solenoid valves at both ends of the third activated carbon adsorption tower 1 are closed. When the adsorption capacity inside the first activated carbon adsorption tower 1 reaches the threshold, the solenoid valves at both ends of the first activated carbon adsorption tower 1 close to initiate the desorption process. At the same time, the solenoid valves at both ends of the third activated carbon adsorption tower 1 are activated, ensuring that two activated carbon adsorption towers 1 can be in normal operation at the same time. This avoids the problem of the three activated carbon adsorption towers 1 working simultaneously and causing the adsorption capacity to reach the threshold at the same time, resulting in shutdown for desorption. Two sealed pull-out cabinets 23 are inserted inside the activated carbon adsorption tower 1. Each of the two sealed pull-out cabinets 23 contains multiple layers of activated carbon plates. The sealed and removable cabinets 23 facilitate the removal of the activated carbon plates for cleaning and replacement after the exhaust gas treatment is completed.

[0023] like Figure 8 , Figure 9 , Figure 10 As shown, the desorption mechanism includes an upper desorption cylinder 29 and a lower desorption cylinder 30 installed at the upper and lower ends of multiple activated carbon adsorption towers 1, respectively. A third fan 31 is connected to the end of the lower desorption cylinder 30 furthest from the activated carbon adsorption tower 1, and the third fan 31 communicates with the interior of the combustion chamber 3. A cooling component is connected to one end of the upper desorption cylinder 29, and a recovery component is installed between the combustion chamber 3 and the upper desorption cylinder 29. Solenoid valves are installed at the connections between the upper desorption cylinder 29, the lower desorption cylinder 30, and the activated carbon adsorption tower 1. The lower desorption cylinder 30 cooperates with the third fan 30... The suction force generated by the blower 31 draws the particles adsorbed on the activated carbon plate from top to bottom and transports them to the combustion chamber 3; the upper desorption cylinder 29 can work with the cooling component to rapidly cool the activated carbon adsorption tower 1 when it is under high temperature alarm, and can also work with the fourth blower 37 to perform heat recovery function (because filtration is from bottom to top, so extraction is from top to bottom); multiple solenoid valves work with the external intelligent control terminal to analyze the signals fed back from each part and realize the functions of cooling, desorption and filtration of activated carbon adsorption tower 1.

[0024] A heating layer 32 is installed at the upper part of the combustion chamber 3. The air inlet of the combustion chamber 3 is located on one side of the heating layer 32. A through groove is opened on one side of the bottom plate of the heating layer 32, and an L-shaped partition plate is fixed to the bottom of the heating layer 32. An air inlet channel 33 is provided between the partition plate and one inner wall of the combustion chamber 3. A chemical reaction plate 34 and a combustion layer 35 are installed at the lower end of the heating layer 32 between the partition plate and the other inner wall of the combustion chamber 3. The combustion layer 35 is located directly below the chemical reaction plate 34, and the air inlet channel 33, the chemical reaction plate 34, and the combustion layer 35 are interconnected. A drain outlet 36 is opened in the middle of the combustion chamber 3, and the drain outlet 36 is adjacent to the chemical reaction plate 34. The heating layer 32 facilitates the preliminary heating of the drawn-in exhaust gas, so that the particulate matter can be quickly burned when it reaches the combustion layer 35. After the exhaust gas enters the combustion chamber 3, it is first preheated by the heating layer 32, and then enters the air inlet channel 33 through the through groove, and then passes through the chemical reaction plate 34. The air intake channel 33 reaches the combustion layer 35 and then passes through the chemical reaction plate 34. The combustion layer 35 is composed of multiple high-temperature heating rods. When the particulate matter is preheated and reaches the combustion layer 35, it is rapidly heated to the ignition point of the particulate matter. The particulate matter and harmful substances in the exhaust gas can be burned at high temperature through the combustion layer 35. The gas after combustion is decomposed into water and carbon dioxide by the chemical reaction plate 34. The inner wall of the chemical reaction plate 34 is honeycomb-shaped, and the porous inner wall is coated with non-precious metals such as manganese oxide / cerium zirconium composite oxide / perovskite catalyst. After the combustion layer 35 burns the particulate matter, the temperature of the chemical reaction plate 34 is lower than that of the combustion layer 35. Water vapor molecules directly contact the active site surface of the chemical reaction plate 34 with the airflow and generate water on the chemical reaction plate 34. The water after the chemical reaction slides down and is discharged through the drain outlet 36. The top surface of the chemical reaction plate 34 has a sloping section that is inclined downward towards the drain outlet 36.

[0025] The cooling assembly includes a liquid nitrogen tank 8 located at the rear end of the upper desorption cylinder 29 and a thermometer 24 installed on the activated carbon adsorption tower 1. The liquid nitrogen tank 8 facilitates the storage of liquid nitrogen and provides rapid cooling when the activated carbon adsorption tower 1 alarms for high temperature. The output end of the liquid nitrogen tank 8 is connected to one end of the upper desorption cylinder 29, and a solenoid valve is installed at the output end of the liquid nitrogen tank 8.

[0026] The recovery assembly includes an exhaust port located on the combustion chamber 3, between the heating layer 32 and the chemical reaction plate 34. The exhaust port is connected to a fourth fan 37, which facilitates the extraction of gases after combustion. The output end of the fourth fan 37 is connected to the upper desorption cylinder 29 and the cooling cylinder 38 via ducts. The end of the cooling cylinder 38 away from the duct is connected to the exhaust pipe 2, and a diversion valve is installed at the connection between the upper desorption cylinder 29 and the duct.

[0027] During normal operation, the diversion valve is open, the solenoid valve at the connection between the activated carbon adsorption tower 1 and the upper desorption cylinder 29 is open, and the solenoid valve at the output end of the liquid nitrogen tank 8 is closed. After the fourth fan 37 extracts the gas, part of the gas enters the exhaust stack 2 through the cooling stack 38, and the other part of the gas flows back into the activated carbon adsorption tower 1 through the upper desorption cylinder 29. Utilizing the heat generated after its own combustion, the gas rapidly burns particulate matter when it passes through the combustion layer 35 a second time, reducing the power consumption of the combustion layer 35 and achieving heat recovery. The activated carbon adsorption tower 1 carries heat and may generate high temperatures after prolonged desorption. When the thermometer 24 senses that the temperature is too high, the solenoid valve at the connection between the activated carbon adsorption tower 1 and the upper desorption cylinder 29 closes, preventing hot gas from entering the activated carbon adsorption tower 1. The solenoid valve at the output end of the liquid nitrogen tank 8 opens, and the liquid nitrogen tank 8 delivers nitrogen to the activated carbon adsorption tower 1 for cooling. At the same time, the diversion valve closes, and the gas drawn by the fourth fan 37 directly enters the exhaust pipe 2 through the cooling exhaust pipe 38 and is discharged, ensuring the flow of the device's tail gas treatment while cooling.

[0028] In this embodiment, the present invention also proposes a method for using a VOCs tail gas treatment device in a coking plant gas purification system, comprising the following steps: Step 1: Before starting the equipment, check to ensure that all components are securely connected, the liquid level in the spray tower 4 is normal (an external water inlet pipe can be added to the main flow pipe of the pressurized water pump 15 to ensure sufficient spray water), the electrolyte in the electrolysis cell 14 is sufficient, the activated carbon plate in the activated carbon adsorption tower 1 is installed in place, all valves are in the initial closed state, and the straight filter screen 21 and the pleated filter screen 22 of the dry filter 7 are clean and free from blockage.

[0029] Step two: Start the first fan 6 and the second fan 27. The first fan 6 generates suction, introducing the VOCs tail gas generated by the coking plant's gas purification system into the spray tower 4. The VOCs tail gas first enters the cyclone separator 10 at the lower end of the spray tower 4. Under the rotation of the turbine blades 18 and the special shape of the turbulence ring 17, a vortex airflow is formed. At the same time, the circulation mechanism starts working, and the pressurized water pump 15 draws out the spray liquid after electrolytic purification in the electrolytic cell 14. A portion of it is transported to the turbulent water pipe through the second branch pipe and then through the spray heads. 20 sprays downwards, making full contact with the rising exhaust gas. The spray liquid absorbs and neutralizes the dust, acid mist, alkaline mist, and water-soluble harmful gases in the exhaust gas. Another part enters the distributor 16 through the first branch pipe, and then is transported to the high-pressure nozzle 19 through the pressurized water pipe to wash the turbine fan blades 18, forming a water film to wet the exhaust gas and clean the fan blades. The washed-off particles and spray wastewater fall into the waste liquid recovery layer 9, and after being filtered by the anti-clogging grille 13, they enter the electrolytic cell 14 for electrolytic treatment again to achieve water recycling.

[0030] Step 3: After preliminary treatment by the spray tower 4, the exhaust gas, carrying a small amount of liquid droplets, rises to the demister plate 12. The demister plate 12 efficiently separates the liquid droplets and mist entrained in the exhaust gas, achieving gas-liquid separation. Subsequently, under the action of the first fan 6, the exhaust gas enters the dry filter 7, passing through two layers of straight filter screens 21 and the middle pleated filter screen 22, further separating solid particles, dust, and other impurities in the gas through physical means. The purified exhaust gas then enters the activated carbon adsorption tower 1 through the fire damper 5. At this time, according to the instructions from the intelligent control terminal... Open the solenoid valves at both ends of the activated carbon adsorption tower 1 (e.g., the first two), and the exhaust gas enters the activated carbon adsorption tower 1 through the inlet outer cylinder 25. It passes through the multi-layer activated carbon plates in the sealed pull-out cabinet 23 from bottom to top. The activated carbon plates efficiently capture VOCs, malodorous gases, acidic gases, alkaline gases and some harmful impurities in the exhaust gas. The purified gas is drawn to the exhaust pipe 2 by the suction of the second fan 27 through the exhaust outer cylinder 26, and finally discharged from the top of the exhaust pipe 2. The rainproof eaves 28 prevent rainwater from entering.

[0031] Step four: When the adsorption of activated carbon plates in a certain activated carbon adsorption tower 1 (such as the first one) reaches the threshold, the intelligent control terminal closes the solenoid valves at both ends of the activated carbon adsorption tower 1, starts the desorption mechanism, and opens the solenoid valve between the lower desorption cylinder 30 and the combustion chamber 3 corresponding to the activated carbon adsorption tower 1, as well as the third blower 31. The third blower 31 generates suction, which draws the impurities adsorbed on the activated carbon plates from top to bottom through the lower desorption cylinder 30 to the combustion chamber 3. After entering the combustion chamber 3, the impurities are first preheated by the heating layer 32, and then pass through the through groove. The gas enters the intake channel 33 and reaches the combustion layer 35 for high-temperature combustion. The gas after combustion is decomposed into water and carbon dioxide through the chemical reaction plate 34. The water is discharged through the drain outlet 36. At the same time, the recovery component is activated and the fourth fan 37 extracts the gas after combustion. Part of the gas flows back to the activated carbon adsorption tower 1 that is desorbing through the upper desorption cylinder 29, using the gas's own heat to assist desorption, reduce the power of the combustion layer 35, and realize heat energy recovery. The other part of the gas enters the exhaust pipe 2 through the cooling exhaust pipe 38 and is discharged.

[0032] Step 5: During the desorption process, if the thermometer 24 on the activated carbon adsorption tower 1 senses that the temperature is too high, the intelligent control terminal immediately closes the solenoid valve at the connection between the activated carbon adsorption tower 1 and the upper desorption cylinder 29 to stop the hot gas backflow. At the same time, the solenoid valve at the output end of the liquid nitrogen tank 8 is opened to transport nitrogen through the upper desorption cylinder 29 into the activated carbon adsorption tower 1 for rapid cooling. At this time, the diversion valve is closed, and the gas drawn by the fourth fan 37 is directly discharged through the exhaust pipe 2 to ensure the safe operation of the device. At the same time, the intelligent control terminal opens the solenoid valves at both ends of the third activated carbon adsorption tower 1 to put it into operation, ensuring that two activated carbon adsorption towers 1 are always in normal filtration state.

[0033] Step 6: During equipment operation, periodically open the double-sealed door of the dry filter 7, remove the straight filter screen 21 and the folded filter screen 22 for cleaning; after the exhaust gas is treated, turn off all fans and valves, pull out the sealed pull-out cabinet 23 in the activated carbon adsorption tower 1, clean or replace the activated carbon plate, and clean the impurities in the waste liquid recovery layer 9.

[0034] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0035] The detailed descriptions listed above are merely specific descriptions of feasible implementation methods of this application and are not intended to limit the scope of protection of this application. All equivalent implementation methods or modifications made without departing from the spirit of the art of this application should be included within the scope of protection of this invention.

Claims

1. A VOCs off-gas treatment apparatus for a coking plant coal gas purification system, characterized by, The system includes an activated carbon adsorption tower (1), an exhaust stack (2) located on one side of the activated carbon adsorption tower (1), a combustion chamber (3) located between the exhaust stack (2) and the activated carbon adsorption tower (1), and a spray tower (4) located on the other side of the activated carbon adsorption tower (1). The upper end of the spray tower (4) is equipped with a spraying mechanism for preliminary adsorption of the exhaust gas, and the lower end of the spray tower (4) is equipped with a circulation mechanism to reduce the amount of water used for spraying. The output end of the spray tower (4) is connected to the activated carbon adsorption tower (1). A desorption mechanism is installed between the activated carbon adsorption tower (1) and the combustion chamber (3). When the adsorption capacity of the activated carbon adsorption tower (1) reaches a threshold value, the desorption mechanism will... The impurities on the adsorbed carbon layer inside the activated carbon adsorption tower (1) are discharged into the combustion chamber (3) for treatment; the desorption mechanism includes an upper desorption cylinder (29) and a lower desorption cylinder (30) installed at the upper and lower ends of the activated carbon adsorption tower (1), respectively. The lower desorption cylinder (30) is connected to a third fan (31) at the end away from the activated carbon adsorption tower (1), and the third fan (31) is connected to the inside of the combustion chamber (3); a cooling component is connected to one end of the upper desorption cylinder (29), and a recovery component is installed between the combustion chamber (3) and the upper desorption cylinder (29). Solenoid valves are installed at the connection between the upper desorption cylinder (29), the lower desorption cylinder (30) and the activated carbon adsorption tower (1).

2. A VOCs off-gas treatment apparatus for a coking plant coal gas cleaning system according to claim 1, characterized in that, The circulation mechanism includes a waste liquid recovery layer (9) located at the bottom of the spray tower (4). An anti-clogging grid (13) is installed on the top of the waste liquid recovery layer (9). The top of the anti-clogging grid (13) has a cone-shaped guide slope. An electrolytic cell (14) is separated from one corner of the waste liquid recovery layer (9) by a partition. An electrolyzer is installed in the electrolytic cell (14). One end of the electrolyzer is pumped by a micro water pump to the waste water in the waste liquid recovery layer (9) for electrolytic separation. A pressurized water pump (15) is installed on one side of the spray tower (4). One end of the pressurized water pump (15) is connected to the inside of the electrolytic cell (14). The other end of the pressurized water pump (15) is divided into a first branch pipe and a second branch pipe. The first branch pipe is connected to a distributor (16), and the second branch pipe is connected to the spray mechanism.

3. The VOCs tail gas treatment equipment for a coking plant gas purification system according to claim 2, characterized in that, The spraying mechanism includes multiple cyclone tubes (10) installed directly above the waste liquid recovery layer (9). A humidification layer (11) is installed at the upper end of the cyclone tubes (10). A turbulent water pipe is installed at the upper end of the humidification layer (11). Multiple branch pipes corresponding to the multiple cyclone tubes (10) are branched off from the turbulent water pipes. Each branch pipe is equipped with a downward spray head (20). The turbulent water pipe is connected to the second branch pipe. A demister plate (12) is installed at the upper end of the turbulent water pipe.

4. A VOCs tail gas treatment device for a coking plant gas purification system according to claim 3, characterized in that, A turbulence ring (17) is installed inside the cyclone (10). Both ends of the turbulence ring (17) are horn-shaped. A turbine fan blade (18) is rotatably connected inside the turbulence ring (17) through a cross mounting bracket. A pressurized water pipe is installed on the cross mounting bracket. A high-pressure nozzle (19) facing the turbine fan blade (18) is installed at one end of the pressurized water pipe. The other end of the pressurized water pipe is connected to the distributor (16).

5. A VOCs tail gas treatment device for a coking plant gas purification system according to claim 1, characterized in that, The output end of the spray tower (4) is connected to a dry filter (7) via a first fan (6), and the dry filter (7) is connected to the activated carbon adsorption tower (1).

6. A VOCs tail gas treatment device for a coking plant gas purification system according to claim 5, characterized in that, The dry filter (7) has two layers of straight filter screens (21) installed inside, and a folded filter screen (22) is installed between the two layers of straight filter screens (21). A double-opening sealed door is hinged on one side of the dry filter (7), and a limit lock is installed on the double-opening sealed door. The dry filter (7) is connected to the activated carbon adsorption tower (1) through a fire damper (5).

7. A VOCs tail gas treatment device for a coking plant gas purification system according to claim 6, characterized in that, There are multiple activated carbon adsorption towers (1), and the upper ends of the multiple activated carbon adsorption towers (1) are connected to the same exhaust outer cylinder (26), and the lower ends of the multiple activated carbon adsorption towers (1) are connected to the same air inlet outer cylinder (25); the fire valve (5) is connected to the air inlet outer cylinder (25) at the lower end of the activated carbon adsorption tower (1); the exhaust outer cylinder (26) is connected to a second fan (27), the output end of the second fan (27) is connected to the bottom end of the exhaust cylinder (2), and a conical rainproof eaves (28) is installed at the top of the exhaust cylinder (2); both the upper and lower ends of the activated carbon adsorption tower (1) are equipped with solenoid valves, and a sealed pull-out cabinet (23) is inserted into the activated carbon adsorption tower (1), and multiple layers of activated carbon plates are placed inside the sealed pull-out cabinet (23).

8. A VOCs tail gas treatment device for a coking plant gas purification system according to claim 1, characterized in that, A heating layer (32) is installed at the upper part of the combustion chamber (3). The air inlet of the combustion chamber (3) is located on one side of the heating layer (32). A through groove is opened on one side of the bottom plate of the heating layer (32). An L-shaped partition plate is fixed to the bottom of the heating layer (32). An air inlet channel (33) is provided between the partition plate and the inner wall of one side of the combustion chamber (3). A chemical reaction plate (34) and a combustion layer (35) are installed at the lower end of the heating layer (32) between the partition plate and the inner wall of the other side of the combustion chamber (3). The combustion layer (35) is located directly below the chemical reaction plate (34). The air inlet channel (33), the chemical reaction plate (34) and the combustion layer (35) are interconnected. A drain outlet (36) is opened in the middle of the combustion chamber (3). The drain outlet (36) is adjacent to the chemical reaction plate (34).

9. A VOCs tail gas treatment device for a coking plant gas purification system according to claim 8, characterized in that, The recovery assembly includes an exhaust port located on the combustion chamber (3) between the heating layer (32) and the chemical reaction plate (34). The exhaust port is connected to a fourth fan (37), which extracts the gas after combustion reaction. The output end of the fourth fan (37) is connected to the upper desorption cylinder (29) and the cooling cylinder (38) through the air duct. The end of the cooling cylinder (38) away from the air duct is connected to the exhaust pipe (2), and a diversion valve is installed at the connection between the upper desorption cylinder (29) and the air duct.

10. A VOCs tail gas treatment device for a coking plant gas purification system according to claim 1, characterized in that, The cooling assembly includes a liquid nitrogen tank (8) located at the rear end of the upper desorption cylinder (29) and a thermometer (24) installed on the activated carbon adsorption tower (1). The output end of the liquid nitrogen tank (8) is connected to one end of the upper desorption cylinder (29), and a solenoid valve is installed at the output end of the liquid nitrogen tank (8).

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