A recovery treatment system for VOCs waste gas treatment

Abstract

The application discloses a recovery treatment system for VOCs waste gas treatment, which comprises a methanol recovery tank area, a water washing tower connected with the methanol recovery tank area, a variable frequency fan arranged at the gas inlet end of the water washing tower and used for introducing methanol waste gas into the water washing tower, an air cooler connected with the gas outlet end of the water washing tower and used for carrying out dewatering treatment on methanol vapor, an activated carbon adsorption device connected with one end of the air cooler and capable of carrying out activated carbon adsorption on the dewatered and separated methanol vapor, and an exhaust pipe arranged at the gas outlet end of the activated carbon adsorption device and used for directly discharging the purified gas into the atmosphere.

Description

Technical Field

[0001] This invention belongs to the technical field of VOCs waste gas treatment equipment, specifically a VOCs waste gas treatment and recovery system. Background Technology

[0002] Regarding environmental pollution, my country has promulgated numerous laws, regulations, and standards to control enterprise emissions, all of which provide clear guidelines for emissions from tank farms and loading stations. Meanwhile, from an economic perspective, methanol gas, the main component of methanol exhaust, is recyclable; direct emission would result in significant waste. Currently, common end-of-pipe control technologies for methanol exhaust include: combustion, adsorption, absorption, condensation, photocatalysis, biodegradation, plasma technology, and membrane separation technology.

[0003] Adsorption methods offer advantages such as simple equipment, ease of operation, safety, and environmental friendliness, making them the most widely used method for methanol waste gas recovery. The main drawback of activated carbon adsorption technology is the large amount of adsorbent required and the need for regular replacement; therefore, extending the service life of activated carbon is a pressing technical challenge that needs to be addressed.

[0004] Therefore, those skilled in the art provide a VOCs waste gas treatment and recovery system to solve the problems mentioned in the background art. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides the following technical solution: a VOCs waste gas treatment and recovery system, comprising:

[0006] Methanol recovery tank area;

[0007] A water washing tower is connected to the methanol recovery tank area. The air inlet of the water washing tower is equipped with a variable frequency fan to introduce methanol waste gas into the water washing tower.

[0008] An air cooler, connected to the exhaust end of the water washing tower, is used for the dehydration treatment of methanol vapor;

[0009] An activated carbon adsorption device is connected to one end of the air cooler, and the activated carbon adsorption device can adsorb methanol vapor after dehydration and separation.

[0010] An external discharge pipe is installed at the exhaust end of the activated carbon adsorption device to directly discharge the purified gas into the atmosphere.

[0011] Furthermore, as a preferred embodiment, a connecting pipe is provided on one side of the variable frequency fan, and a standby fan is also provided on the connecting pipe. The standby fan and the variable frequency fan operate independently of each other.

[0012] Furthermore, preferably, the activated carbon adsorption device includes:

[0013] Mounting rack;

[0014] The steering shaft is rotatably mounted on the mounting bracket;

[0015] A drive motor is fixed on the mounting bracket, and the output end of the drive motor is fixed to the steering shaft;

[0016] The activated carbon adsorption tanks are two symmetrically arranged, and each activated carbon adsorption tank is fixed to the steering shaft via a connecting shaft bracket;

[0017] An intake pipe and an exhaust pipe are symmetrically arranged at the upper and lower ends of the activated carbon adsorption tank on one side. One end of the intake pipe is connected to the air cooler, and one end of the exhaust pipe is connected to the external discharge pipe.

[0018] An activated carbon desorption assembly is located at the activated carbon adsorption tank on the other side.

[0019] Furthermore, as a preferred embodiment, the ends of the air intake pipe, the exhaust pipe, and the activated carbon desorption component are all fixed with sealing end pieces. A fastening plate is connected to the sealing end piece via a telescopic tube. An annular groove is provided at the end of the activated carbon adsorption tank. A sealing ring is embedded and fixed on the fastening plate. The sealing ring can seal and cooperate with the annular groove. A telescopic guide rod is connected between the sealing end piece and the fastening plate.

[0020] Furthermore, as a preferred embodiment, the activated carbon adsorption tank is symmetrically arranged with multiple adsorption plates, each of which is filled with activated carbon. A mounting frame plate is horizontally fixed between the adsorption plates on the same side, and an inner shaft tube is fixed at the center between the mounting frame plates. One side of each adsorption plate is connected to the activated carbon adsorption tank through a support spring. Multiple airflow guiding components are also embedded in the activated carbon adsorption tank.

[0021] Furthermore, preferably, the activated carbon desorption component includes:

[0022] External positioning tube;

[0023] An inner connecting tube is slidably disposed inside the outer positioning tube. One end of the inner connecting tube is rotatably provided with a shaft connecting tube, and one end of the shaft connecting tube abuts against and contacts the inner shaft tube.

[0024] A sealing connector is fixed to one end of the shaft connector, and one end of the sealing connector slides into the inner shaft tube.

[0025] An upper fixing tube is installed above the outer positioning tube, and one end of the upper fixing tube is connected to an external vacuum pump; and

[0026] A high-temperature steam pipe is connected to the internal connecting pipe.

[0027] Furthermore, as a preferred embodiment, a toothed disc is fixed to one end of the inner connecting tube near the inner shaft tube. The toothed disc can abut against the inner shaft tube, and the surface of the inner shaft tube is provided with tooth grooves. The inner shaft tube is also provided with multiple air holes.

[0028] Furthermore, preferably, the airflow guiding component includes:

[0029] A fixing ring seat is embedded and fixed inside the activated carbon adsorption tank;

[0030] A rotating ring is rotatably disposed within a fixed ring seat. The fixed ring seat is provided with driving teeth, which are connected to the rotating ring for transmission via gear meshing.

[0031] Adjust the fan blades, which are circumferentially distributed on the inner wall of the rotating ring.

[0032] Furthermore, as a preferred embodiment, the adjustable fan blades are rotatably mounted on the rotating ring, and their deflection angle ranges from -20° to 20°.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. This invention adds an "activated carbon adsorption" protection process to ensure that exhaust gas meets standards even when indicators are abnormal. The activated carbon adsorption device is a disposable adsorption device; the activated carbon packing is replaced when the activated carbon in the device is saturated, reducing the activated carbon regeneration process and ensuring the complexity and operability of the treatment process.

[0035] 2. The activated carbon desorption component provided in this invention can realize activated carbon desorption, remove the pollutants adsorbed therein, and thus realize the desorption and regeneration process. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the technical route for treating methanol waste gas by adsorption method according to the present invention.

[0037] Figure 2 This is a schematic diagram of the activated carbon adsorption device in this invention. Figure One ;

[0038] Figure 3 This is a schematic diagram of the activated carbon adsorption device in this invention. Figure Two ;

[0039] Figure 4 This is a schematic diagram of the sealing end component in this invention;

[0040] Figure 5 This is a schematic diagram of the activated carbon adsorption tank in this invention;

[0041] Figure 6 This is a schematic diagram of the activated carbon desorption component in this invention;

[0042] Figure 7 This is a schematic diagram of the airflow guiding component in this invention;

[0043] In the diagram: 1. Activated carbon adsorption device; 11. Mounting frame; 12. Drive motor; 13. Steering shaft; 14. Inlet pipe; 15. Exhaust pipe; 2. Activated carbon adsorption tank; 21. Sealing ring; 22. Sealing end piece; 23. Fastening plate; 24. Telescopic guide rod; 25. Telescopic tube; 3. Activated carbon desorption assembly; 31. Outer positioning tube; 32. Shaft tube; 33. Inner connecting tube; 34. Toothed disc; 35. Sealing tube; 36. Upper fixing tube; 4. Adsorption plate; 41. Mounting frame plate; 42. Inner shaft tube; 43. Support spring; 5. Airflow guiding assembly; 51. Fixed ring seat; 52. Rotating ring; 53. Adjusting fan blade. Detailed Implementation

[0044] Please see Figures 1-7 In this embodiment of the invention, a VOCs waste gas treatment and recovery system includes:

[0045] Methanol recovery tank area;

[0046] A water washing tower is connected to the methanol recovery tank area. The air inlet of the water washing tower is equipped with a variable frequency fan to introduce methanol waste gas into the water washing tower.

[0047] An air cooler, connected to the exhaust end of the water washing tower, is used for the dehydration treatment of methanol vapor;

[0048] An activated carbon adsorption device 1 is connected to one end of the air cooler, and the activated carbon adsorption device 1 can adsorb methanol vapor after dehydration and separation.

[0049] An external discharge pipe is installed at the exhaust end of the activated carbon adsorption device 1 to directly discharge the purified gas into the atmosphere. A spray scrubbing purification tower is selected as the main treatment process to minimize operating costs and plant area usage. The methanol and fusel oil waste liquid washed off by the spray scrubbing purification tower serves as a carbon source for the existing wastewater treatment plant in the plant area, providing nutrients for the plant's microorganisms. This effectively treats the waste gas, improves the treatment efficiency of the wastewater treatment plant, and reduces the cost of adding chemicals to the plant.

[0050] In this embodiment, a connecting pipe is installed on one side of the variable frequency fan, and a standby fan is also installed on the connecting pipe. The standby fan and the variable frequency fan operate independently. That is to say, the methanol tank area of ​​this project has a processing capacity of 300 m3 / h. Considering the high amount of methanol in the inlet gas, and the fact that the spray tower guarantees an 80% removal rate of methanol in the exhaust gas, even with a 4-stage spray tower, it is still difficult to meet the standard. In order to reduce the investment of the project and at the same time reduce the methanol concentration in the exhaust gas and reduce the explosion coefficient of the exhaust gas, this solution adds a connecting pipe before the variable frequency fan to dilute the exhaust gas. According to calculations, the processing air volume of the methanol tank area needs to be diluted to 900 m3 / h. Considering the fluctuation of the alcohol index in the exhaust gas, the emergency treatment air volume is taken as twice the dilution air volume, which is 1800 m3 / h. The variable frequency fan and the standby fan are selected with a flow rate of 1800 m3 / h. During normal operation, one fan is started. When the air volume is large, both fans are started simultaneously. Similarly, the actual air volume handled by the finished product tank area and loading arm area is 2000 m³ / h, and the emergency air volume is 4000 m³ / h. Variable frequency fans and standby fans with a flow rate of 2000 m³ / h are selected. During normal operation, one fan is started; when the air volume is large, both fans are started simultaneously.

[0051] In a preferred embodiment, the activated carbon adsorption device 1 includes:

[0052] Mounting bracket 11;

[0053] The steering shaft 13 is rotatably mounted on the mounting bracket 11;

[0054] The drive motor 12 is fixed on the mounting bracket 11, and the output end of the drive motor 12 is fixed to the steering shaft 13;

[0055] The activated carbon adsorption tank 2 consists of two symmetrically arranged tanks, and each activated carbon adsorption tank 2 is fixed to the steering shaft 13 via a connecting shaft bracket;

[0056] An intake pipe 14 and an exhaust pipe 15 are symmetrically arranged at the upper and lower ends of the activated carbon adsorption tank 2 on one side. One end of the intake pipe 14 is connected to the air cooler, and one end of the exhaust pipe 15 is connected to the external discharge pipe.

[0057] The activated carbon adsorption component 3 is located on the other side of the activated carbon adsorption tank 2. The activated carbon adsorption tank is mainly used for the treatment of organic waste gas and is primarily an adsorber, containing components such as a uniform air distribution network and an activated carbon adsorption layer. This device is made of 3.0mm thick 304 stainless steel. High-quality granular activated carbon is used. This activated carbon has tiny pores and extremely strong adsorption capacity. Due to its large surface area, it can fully contact the gas. When the gas comes into contact with the pores, it is adsorbed, thus achieving purification. The activated carbon adsorption box is a purification device with excellent effects in treating organic waste gas and odor removal. Activated carbon adsorption can effectively remove odors, natural and synthetic dissolved volatile organic compounds, and micropollutants from waste gas. Driven by a motor, the two activated carbon adsorption tanks rotate alternately, allowing one to work while the other is regenerated. When the activated carbon in one adsorption tank is saturated, a desorption and regeneration process is performed.

[0058] In this embodiment, the ends of the air inlet pipe 14, the exhaust pipe 15, and the activated carbon desorption component 3 are all fixed with sealing end pieces 22. The sealing end pieces 22 are connected to the fastening plate 23 via telescopic pipes 25. The end of the activated carbon adsorption tank 2 is provided with an annular groove. A sealing ring 21 is embedded and fixed on the fastening plate 23. The sealing ring 21 can seal and cooperate with the annular groove. A telescopic guide rod 24 is connected between the sealing end pieces 22 and the fastening plate 23, so that a sealed docking operation can be achieved when the two activated carbon adsorption tanks are replaced, thus preventing gas leakage.

[0059] In this embodiment, multiple adsorption plates 4 are symmetrically arranged in the activated carbon adsorption tank 2, each adsorption plate 4 is filled with activated carbon, and a mounting frame plate 41 is horizontally fixed between the adsorption plates 4 on the same side. An inner shaft tube 42 is fixed in the center between the mounting frame plates 41. One side of the adsorption plate 4 is connected to the activated carbon adsorption tank 2 through a support spring 43. Multiple airflow guiding components 5 are also embedded in the activated carbon adsorption tank 2.

[0060] In this embodiment, the activated carbon desorption component 3 includes:

[0061] External positioning tube 31;

[0062] The inner connecting tube 33 is slidably disposed inside the outer positioning tube 31. One end of the inner connecting tube 33 is rotatably provided with a shaft connecting tube 32, and one end of the shaft connecting tube 32 abuts against the inner shaft tube 42.

[0063] A sealing connector 35 is fixed to one end of the shaft connector 32, and one end of the sealing connector 35 slides into the inner shaft tube 42.

[0064] The upper fixing tube 36 is mounted above the outer positioning tube 31, and one end of the upper fixing tube 36 is connected to an external vacuum pump; and

[0065] A high-temperature steam pipe (not shown in the figure) is connected to the internal connecting pipe 33. Steam can be introduced into the high-temperature steam pipe, so that the activated carbon on the adsorption plate enters the heating stage. The gas after the heating stage can be discharged through the upper fixed pipe. The high-concentration methanol gas that comes out through the external vacuum pump re-enters the inlet of the water washing tower and is circulated and absorbed.

[0066] In a preferred embodiment, a toothed disc 34 is fixed to one end of the inner connecting pipe 33 near the inner shaft tube 42. The toothed disc 34 can abut against the inner shaft tube 42, and the surface of the inner shaft tube 42 is provided with tooth grooves. The inner shaft tube 42 is also provided with multiple air holes. In particular, when the shaft tube is continuously rotated, the toothed disc drives the inner shaft tube to perform axial high-frequency oscillation. At this time, each adsorption plate can be pushed by the inner shaft tube to make the activated carbon turn over and vibrate. At the same time, steam is introduced into the air holes on the inner shaft tube to realize rapid heating of the activated carbon and improve the desorption effect.

[0067] In this embodiment, the airflow guiding component 5 includes:

[0068] The fixing ring seat 51 is embedded and fixed inside the activated carbon adsorption tank 2;

[0069] A rotating ring 52 is rotatably disposed within a fixed ring seat 51. The fixed ring seat 51 is provided with driving teeth, which are connected to the rotating ring 52 via gear meshing.

[0070] Adjust the fan blades 53, which are circumferentially distributed on the inner wall of the rotating ring 52, wherein the rotating rings in each fixed ring seat can rotate independently, thereby changing the airflow direction in the activated carbon adsorption tank.

[0071] In this embodiment, the adjusting fan blade 53 is rotatably mounted on the rotating ring 52, and its deflection angle ranges from -20° to 20°. In particular, during activated carbon desorption, steam enters the activated carbon adsorption tank through the inner shaft tube. At this time, the adjusting fan blades located at various locations can guide the airflow. The adjusting fan blades located on both sides can be tilted, so that the steam can be completely diffused into the activated carbon adsorption tank and form an internal vortex, which has a high penetration effect and improves the activated carbon desorption effect.

[0072] Specifically, the methanol waste gas recovery and treatment process involves separating the VOC mixture from the waste gas in the recovery tank area, and using the methanol-water solution as a carbon source in the wastewater treatment plant's pipeline system. The separated air, meeting the emission standards, can be directly discharged into the atmosphere. This process includes the following steps:

[0073] 1) Air intake (air collection) stage:

[0074] Using a variable frequency fan (at the rear end of the adsorption tank), and through the interlocking control of the inlet pressure transmitter of the methanol exhaust gas treatment device, the methanol-air mixture generated during the breathing of the methanol tank area and the venting process of loading is led to the water washing tower. To avoid uneven pressure, a pressure stabilizing device is added to the front-end air inlet pipeline.

[0075] 2) Absorption (washing) stage

[0076] The methanol waste gas is absorbed in a water washing tower using water provided by the owner. Water is pumped to the top of the water washing tower, where most of the methanol waste gas is absorbed. The liquid level in the water washing tower is controlled by a level transmitter and a water washing pump (one for standby, frequency converter) to maintain a stable level. The liquid discharged from the top outlet of the water washing tower, containing a small amount of methanol vapor and some water vapor, enters an air cooler to condense water vapor for further dehydration treatment, and then goes to the downstream condensate tank for gas-liquid separation.

[0077] 3) Adsorption process

[0078] The separated methanol vapor, free of water vapor, is fed into activated carbon adsorption tanks for adsorption treatment. The activated carbon adsorption tanks (carbon beds) are installed in parallel. After system startup, one activated carbon adsorption tank is in "adsorption" mode, while the other is in "desorption" mode (i.e., activated carbon desorption via an activated carbon desorption component). When the methanol vapor in the "adsorption" carbon bed reaches saturation, the vacuum pump starts, and the "adsorption" activated carbon adsorption tank switches to "desorption and regeneration" mode. Simultaneously, the "desorption" activated carbon adsorption tank switches back to "adsorption" mode. This alternating cycle of activated carbon adsorption tank operation ensures the continuous treatment of methanol vapor entering the unit. The purified gas is then discharged directly into the atmosphere through an external exhaust pipe.

[0079] 4) Analysis phase

[0080] Once the methanol vapor in the activated carbon adsorption tank reaches saturation, desorption is performed through an activated carbon desorption component in conjunction with a vacuum pump system. The desorbed activated carbon adsorbent can be recycled; the high-concentration methanol gas pumped out by the vacuum pump re-enters the inlet of the water washing tower for further absorption and treatment.

[0081] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A VOCs waste gas treatment and recovery system, characterized in that: It includes: Methanol recovery tank area; A water washing tower is connected to the methanol recovery tank area. The air inlet of the water washing tower is equipped with a variable frequency fan to introduce methanol waste gas into the water washing tower. An air cooler, connected to the exhaust end of the water washing tower, is used for the dehydration treatment of methanol vapor; An activated carbon adsorption device (1) is connected to one end of the air cooler. The activated carbon adsorption device (1) can adsorb methanol vapor after dehydration and separation. An external discharge pipe is installed at the exhaust end of the activated carbon adsorption device (1) to directly discharge the purified gas into the atmosphere. The activated carbon adsorption device (1) includes: Mounting bracket (11); The steering shaft (13) is rotatably mounted on the mounting bracket (11); A drive motor (12) is fixed on the mounting bracket (11), and the output end of the drive motor (12) is fixed to the steering shaft (13); The activated carbon adsorption tanks (2) are two symmetrically arranged. Each activated carbon adsorption tank (2) is fixed to the steering shaft (13) through a connecting shaft frame. The two activated carbon adsorption tanks are rotated by a drive motor so that they can be replaced by each other. An intake pipe (14) and an exhaust pipe (15) are symmetrically arranged at the upper and lower ends of the activated carbon adsorption tank (2) on one side. One end of the intake pipe (14) is connected to the air cooler, and one end of the exhaust pipe (15) is connected to the external exhaust pipe. The activated carbon desorption component (3) is located at the activated carbon adsorption tank (2) on the other side; The ends of the air intake pipe (14), the exhaust pipe (15), and the activated carbon desorption assembly (3) are all fixed with sealing end pieces (22). The sealing end piece (22) is connected to the fastening plate (23) via the telescopic tube (25). The end of the activated carbon adsorption tank (2) is provided with an annular groove. A sealing ring (21) is embedded and fixed on the fastening plate (23). The sealing ring (21) can seal with the annular groove. A telescopic guide rod (24) is connected between the sealing end piece (22) and the fastening plate (23). The activated carbon adsorption tank (2) is symmetrically equipped with multiple adsorption plates (4) on the upper and lower sides. Each adsorption plate (4) is filled with activated carbon. The adsorption plates (4) on the same side are horizontally fixed with mounting brackets (41). An inner shaft tube (42) is fixed in the center between the mounting brackets (41). One side of the adsorption plate (4) is connected to the activated carbon adsorption tank (2) through a support spring (43). The activated carbon desorption component (3) includes: External positioning tube (31); An inner connecting tube (33) is slidably disposed inside the outer positioning tube (31). One end of the inner connecting tube (33) is rotatably provided with a shaft connecting tube (32), and one end of the shaft connecting tube (32) abuts against the inner shaft tube (42). A sealing connector (35) is fixed to one end of the shaft connector (32), and one end of the sealing connector is slidably inserted into the inner shaft tube (42). The upper fixing tube (36) is mounted above the outer positioning tube (31), and one end of the upper fixing tube (36) is connected to the external vacuum pump; A high-temperature steam pipe is connected to the internal connecting pipe (33); A toothed file disc (34) is fixed on one end of the shaft connector (32) near the inner shaft tube (42). The toothed file disc (34) can abut against the inner shaft tube (42), and the surface of the inner shaft tube (42) is provided with tooth grooves. The inner shaft tube (42) is also provided with multiple air holes. Under the continuous rotation of the shaft connector (32), the toothed file disc (34) drives the inner shaft tube (42) to perform axial high-frequency oscillation.

2. The VOCs waste gas treatment and recovery system according to claim 1, characterized in that: A connecting pipe is provided on one side of the variable frequency fan, and a standby fan is also provided on the connecting pipe. The standby fan and the variable frequency fan operate independently of each other.

3. The VOCs waste gas treatment and recovery system according to claim 1, characterized in that: The activated carbon adsorption tank (2) is also equipped with multiple airflow guiding components (5).

4. The VOCs waste gas treatment and recovery system according to claim 3, characterized in that: The airflow guiding component (5) includes: The fixing ring seat (51) is embedded and fixed inside the activated carbon adsorption tank (2); A rotating ring (52) is rotatably disposed in the fixed ring seat (51). The fixed ring seat (51) is provided with driving teeth, which are connected to the rotating ring (52) for transmission through gear meshing. Adjust the fan blades (53), which are circumferentially distributed on the inner wall of the rotating ring (52).

5. A VOCs waste gas treatment and recovery system according to claim 4, characterized in that: The adjustable fan blade (53) is rotatably mounted on the rotating ring (52), and its deflection angle ranges from -20° to 20°.

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