Tail gas treatment device of waste gas system

Abstract

The utility model provides a tail gas treatment device of a waste gas system and relates to the technical field of waste gas treatment. The device comprises a waste gas absorption tower, a spraying mechanism is arranged in the waste gas absorption tower, an alkali liquor circulating mechanism is communicated with the spraying mechanism and the bottom of the waste gas absorption tower, a tail gas pipe is arranged at the top of the waste gas absorption tower, a fan is arranged on the tail gas pipe, and a wire mesh demister is arranged on the tail gas pipe between the fan and the waste gas absorption tower. Alkaline dropping liquid in tail gas is intercepted, so that frequent cleaning of a fan caused by the fact that the alkaline dropping liquid enters a volute of the fan is avoided.

Description

Technical Field

[0001] This utility model relates to the field of waste gas treatment technology, specifically to a waste gas system tail gas treatment device. Background Technology

[0002] According to the "General Technical Requirements for Chlorine Safety Facilities in Chlor-Alkali Production" (T / CCASC 1003--2021), an emergency chlorine treatment device, i.e., a waste gas treatment system, must be equipped in the chlor-alkali production process. Currently, during the operation of the system, the fan continuously draws the waste gas after the alkaline solution in the absorption tower. The gas carries alkaline droplets into the fan casing. The negative pressure of the fan accelerates the evaporation of the droplets, the temperature decreases, the concentration increases, and the alkaline droplets and some by-products crystallize and precipitate, clogging the fan casing. The fan can only be cleaned and maintained periodically, which is troublesome to operate. Cleaning requires the equipment to be shut down and is difficult, affecting the operation of the equipment and consuming a lot of manpower. Utility Model Content

[0003] The purpose of this invention is to develop an exhaust gas treatment device that can intercept alkaline droplets in exhaust gas, thereby preventing the alkaline droplets from entering the fan casing and causing frequent fan cleaning.

[0004] This utility model is achieved through the following technical solution:

[0005] An exhaust gas treatment device for a waste gas system, comprising:

[0006] Waste gas absorption tower;

[0007] The spraying mechanism is located inside the waste gas absorption tower;

[0008] The alkali circulation mechanism is connected to the spraying mechanism and the bottom of the waste gas absorption tower;

[0009] The exhaust pipe is located at the top of the waste gas absorption tower;

[0010] The fan is installed on the exhaust pipe;

[0011] A wire mesh demister is installed on the tail gas pipe between the fan and the waste gas absorption tower.

[0012] Optionally, the wire mesh demister includes a tank, with a drain pipe and an exhaust pipe connected to the bottom and top of the tank, respectively. An air inlet pipe is also connected to the lower part of the tank. The air inlet pipe is connected to the exhaust pipe, and the exhaust pipe is connected to a fan. Solenoid valves are provided on the air inlet pipe, the exhaust pipe, and the drain pipe. Two wire mesh filter layers are provided inside the tank, and the air inlet pipe is located below the lower wire mesh filter layer.

[0013] Optionally, the tank is provided with a self-cleaning unit, which includes backwash pipe assemblies respectively located above the two wire mesh filter layers in the tank. The bottom of the backwash pipe assembly is provided with multiple nozzles, and the inner wall of the tank is provided with multiple supports connected to the backwash pipe assembly.

[0014] Optionally, the backflush tube assembly includes multiple annular backflush tubes with different diameters and arranged concentrically. The bottom of each backflush tube is provided with multiple downward-facing nozzles, which are arranged at equal intervals on the backflush tube.

[0015] Optionally, multiple support rods are connected between two adjacent backflush pipes. The support rods are arranged radially along the backflush pipes. The multiple support rods are arranged at equal intervals in the circumferential direction of the backflush pipes. The multiple supports are arranged at equal intervals on the inner wall of the tank. The outermost backflush pipe is connected to the multiple supports.

[0016] Optionally, the backflush pipe assembly is connected to multiple nozzles, which extend from the outside of the tank and are connected to the backflush pipe. The nozzles are connected to a gas source or a liquid source and are arranged in a support rod inside the tank.

[0017] Optionally, the two mesh filter layers vertically divide the tank into three cavities, and a pressure sensor is provided on the inner wall of the tank within each cavity.

[0018] Optionally, the air pressure sensor in the upper cavity of the two wire mesh filter layers is located above the backflush tube assembly.

[0019] Optionally, the alkali circulation mechanism includes two alkali circulation tanks, two alkali circulation pumps, and a heat exchanger. The tops of the two alkali circulation tanks are connected to the bottom pipeline of the waste gas absorption tower, the bottoms of the two alkali circulation tanks are respectively connected to the inlet pipelines of the two alkali circulation pumps, the outlets of the two alkali circulation pumps are connected to the heat exchanger, and the heat exchanger is connected to the spraying mechanism.

[0020] Optionally, the top of the two alkali circulation tanks is connected to a replenishment pipe, and a mixer is provided on the pipeline between the heat exchanger and the two alkali circulation pumps. The replenishment pipe is connected to the mixer, and the mixer is connected to an alkali pipe, a water supply pipe, and a chlorine water pipe.

[0021] The beneficial effects of this utility model are:

[0022] This invention filters and traps alkaline droplets in the exhaust gas using a wire mesh demister, significantly reducing the number of alkaline droplets entering the fan casing, greatly extending the fan cleaning and maintenance cycle, and significantly reducing the frequency of equipment downtime for maintenance. The self-cleaning unit inside the wire mesh demister can automatically backwash the wire mesh filter layer when the air permeability of the wire mesh filter layer decreases and the pressure difference between the two sides increases, washing away the impurities attached to the wire mesh filter layer, restoring the air permeability of the wire mesh filter layer, and achieving self-cleaning. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a structural diagram of the present utility model;

[0025] Figure 2 This is a structural diagram of a wire mesh demister;

[0026] Figure 3 This is a top view of the backflushing tube assembly.

[0027] Attached reference numerals: 1. Waste gas absorption tower; 2. Tail gas pipe; 3. Wire mesh demister; 31. Tank; 32. Drain pipe; 33. Exhaust pipe; 34. Inlet pipe; 35. Wire mesh filter layer; 36. Backflush pipe; 37. Support; 38. Spray pipe; 39. Nozzle; 310. Pressure sensor; 311. Support rod; 4. Air venting pipe; 5. Fan; 6. Alkali circulation tank; 7. Alkali circulation pump; 8. Mixer; 9. Heat exchanger. Detailed Implementation

[0028] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0030] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0031] like Figures 1-3As shown, this utility model discloses a waste gas system tail gas treatment device, including a waste gas absorption tower 1. Waste gas is introduced into the waste gas absorption tower 1. A spraying mechanism is provided inside the waste gas absorption tower 1. An alkaline solution circulation mechanism is connected between the spraying mechanism and the bottom of the waste gas absorption tower 1. A tail gas pipe 2 is connected to the top of the waste gas absorption tower 1. A wire mesh demister 3 and a fan 5 are sequentially arranged on the tail gas pipe 2. The exhaust height of the fan 5 outlet is not less than 25 meters. A venting pipe 4 is also connected to the tail gas pipe 2 on the side of the wire mesh demister 3 away from the fan 5.

[0032] The wire mesh demister 3 includes a tank 31. The bottom and top of the tank 31 are respectively connected to a drain pipe 32 and an exhaust pipe 33. The lower part of the tank 31 is also connected to an air inlet pipe 34, which is connected to the exhaust pipe 2. The exhaust pipe 33 is connected to the fan 5. Solenoid valves (not shown in the figure) are provided on the air inlet pipe 34, the exhaust pipe 33, and the drain pipe 32.

[0033] The tank 31 is equipped with two wire mesh filter layers 35. The wire mesh filter layers 35 are existing technologies and will not be described in detail. The air inlet pipe 34 is located below the lower wire mesh filter layer 35. The exhaust gas discharged from the top of the exhaust gas absorption tower 1 enters the tank 31 through the air inlet pipe 34. The exhaust gas flows upward in the tank 31 and passes through the two wire mesh filter layers 35 in sequence before being discharged from the exhaust pipe 33 at the top. The wire mesh filter layer 35 will trap alkaline droplets in the exhaust gas.

[0034] The tank body 31 is equipped with a self-cleaning unit, which automatically cleans the wire mesh filter layer 35 to ensure the filtration performance and air permeability of the wire mesh filter layer 35. The self-cleaning unit includes backwash pipe assemblies respectively located above the two wire mesh filter layers 35 in the tank body 31, and multiple supports 37 connected to the backwash pipe assemblies are correspondingly provided on the inner wall of the tank body 31.

[0035] Specifically, the backflushing tube assembly includes three annular backflushing tubes 36 with different diameters and arranged concentrically. Four support rods 311 arranged in a cross shape are connected between adjacent backflushing tubes 36. The support rods 311 are arranged radially along the backflushing tubes 36. Four supports 37 are provided on the inner wall of the tank 31 outside the backflushing tube assembly. The four supports 37 are arranged at equal intervals on the inner wall of the tank 31. The outermost backflushing tube 36 is connected to the four supports 37, and the backflushing tube assembly is fixed by the supports 37.

[0036] The bottom of the backflushing pipe 36 is provided with multiple downward-facing nozzles 39, which are evenly spaced on the backflushing pipe 36. Four nozzles 38 are connected to the backflushing pipe assembly, and the nozzles 38 are connected to the backflushing pipe 36. The nozzles 38 extend from the outside of the tank body 31 and are connected to a gas source or a liquid source. The nozzles 38 are arranged inside the tank body 31 within the support rod 311 to avoid the nozzles 38 being exposed and thus increasing the volume of the backflushing pipe assembly.

[0037] Two wire mesh filter layers 35 vertically divide the tank body 31 into three cavities. The exhaust gas input through the intake pipe 34 enters the lowest cavity, which is below the lower wire mesh filter layer 35. The exhaust gas then passes upward through the lower wire mesh filter layer 35 and enters the middle cavity, which is between the lower and upper wire mesh filter layers 35. The exhaust gas continues upward through the upper wire mesh filter layer 35 and enters the upper cavity, which is above the upper wire mesh filter layer 35. A pressure sensor 310 is installed on the inner wall of the tank body 31 in each cavity. In the middle and upper cavities, the pressure sensor 310 is located above the backflush pipe assembly and monitors the pressure in the current cavity.

[0038] A control system (not shown in the figure) is installed outside the tank 31. The control system controls the spraying or closing of the nozzle 38. The air pressure sensor 310 is electrically connected to the control system. The control system sets the spraying trigger conditions for the nozzle 38. When the pressure difference ΔP between the two adjacent cavities, that is, the two sides of the tank 31 of the wire mesh filter layer 35, reaches the set value, the control system controls the nozzle 38 to spray and simultaneously closes the valves of the air inlet pipe 34 and the exhaust pipe 33, and opens the valve of the drain pipe 32. The gas or liquid used as backflushing is sprayed out from the nozzle 39 to rinse the wire mesh filter layer 35. The liquid remaining in the tank 31, the rinsing medium, and the impurities washed down by the rinsing medium are discharged from the drain pipe 32, realizing the self-cleaning of the wire mesh filter layer 35. After the self-cleaning is completed, the control system controls the valve of the drain pipe 32 to close and the valves of the air inlet pipe 34 and the exhaust pipe 33 to continue the work of intercepting alkaline droplets in the exhaust gas.

[0039] The alkali circulation mechanism includes two alkali circulation tanks 6, two alkali circulation pumps 7, and a heat exchanger 9. The tops of the two alkali circulation tanks 6 are connected to the bottom pipes of the waste gas absorption tower 1, and the bottoms of the two alkali circulation tanks 6 are respectively connected to the inlet pipes of the two alkali circulation pumps 7. The outlets of the two alkali circulation pumps 7 are connected to the heat exchanger 9, which is connected to the spraying mechanism. The tops of the two alkali circulation tanks 6 are also connected to a makeup liquid pipe. A mixer 8 is installed on the pipe between the heat exchanger 9 and the two alkali circulation pumps 7. The makeup liquid pipe is connected to the mixer 8, and the mixer 8 is also connected to an alkali pipe, a water supply pipe, and a chlorine water pipe.

[0040] This invention filters and traps alkaline droplets in the exhaust gas through a wire mesh demister 3, significantly reducing the number of alkaline droplets entering the volute of the blower 5, greatly extending the cleaning and maintenance cycle of the blower 5, and significantly reducing the frequency of equipment downtime and maintenance. The self-cleaning unit installed in the wire mesh demister 3 can automatically backwash the wire mesh filter layer 35 when the air permeability of the wire mesh filter layer 35 decreases and the pressure difference between the two sides increases, washing away the impurities attached to the wire mesh filter layer 35, restoring the air permeability of the wire mesh filter layer 35 and achieving self-cleaning.

[0041] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the technical solutions of this utility model. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of this utility model patent.

Claims

1. A waste gas system exhaust gas treatment device, characterized in that, include: Waste gas absorption tower; The spraying mechanism is located inside the waste gas absorption tower; The alkali circulation mechanism is connected to the spraying mechanism and the bottom of the waste gas absorption tower; The exhaust pipe is located at the top of the waste gas absorption tower; The fan is installed on the exhaust pipe; A wire mesh demister is installed on the tail gas pipe between the fan and the waste gas absorption tower.

2. The exhaust gas treatment device for the waste gas system according to claim 1, characterized in that, The wire mesh demister includes a tank body, with a drain pipe and an exhaust pipe connected to the bottom and top of the tank body, respectively. An air inlet pipe is also connected to the lower part of the tank body. The air inlet pipe is connected to the exhaust pipe, and the exhaust pipe is connected to the fan. Solenoid valves are provided on the air inlet pipe, the exhaust pipe, and the drain pipe. Two wire mesh filter layers are provided inside the tank body, with the air inlet pipe located below the lower wire mesh filter layer.

3. The exhaust gas treatment device for the waste gas system according to claim 2, characterized in that, The tank is equipped with a self-cleaning unit, which includes backwash pipe assemblies located above the two wire mesh filter layers in the tank. The bottom of the backwash pipe assembly is provided with multiple nozzles, and the inner wall of the tank is provided with multiple supports that are connected to the backwash pipe assembly.

4. The exhaust gas treatment device for the waste gas system according to claim 3, characterized in that, The backflush tube assembly includes multiple annular backflush tubes with different diameters and arranged concentrically. The bottom of each backflush tube has multiple downward-facing nozzles, which are arranged at equal intervals on the backflush tube.

5. The exhaust gas treatment device for a waste gas system according to claim 4, characterized in that, Multiple support rods are connected between two adjacent backflush pipes. The support rods are arranged radially along the backflush pipes. The multiple support rods are arranged at equal intervals in the circumferential direction of the backflush pipes. The multiple supports are arranged at equal intervals on the inner wall of the tank. The outermost backflush pipe is connected to the multiple supports.

6. The exhaust gas treatment device for a waste gas system according to claim 5, characterized in that, The backflush pipe assembly is connected to multiple nozzles. The nozzles extend from the outside of the tank and are connected to the backflush pipe. The nozzles are connected to a gas source or a liquid source. The nozzles are arranged in the support rods inside the tank.

7. The exhaust gas treatment device for a waste gas system according to claim 3, characterized in that, The two mesh filter layers vertically divide the tank into three cavities, and a pressure sensor is installed on the inner wall of the tank within each cavity.

8. The exhaust gas treatment device for a waste gas system according to claim 7, characterized in that, The air pressure sensor in the upper cavity of the two wire mesh filter layers is located above the backflush tube assembly.

9. The exhaust gas treatment device for a waste gas system according to any one of claims 1 to 8, characterized in that, The alkali circulation mechanism includes two alkali circulation tanks, two alkali circulation pumps, and a heat exchanger. The tops of the two alkali circulation tanks are connected to the bottom pipeline of the waste gas absorption tower, the bottoms of the two alkali circulation tanks are respectively connected to the inlet pipelines of the two alkali circulation pumps, the outlets of the two alkali circulation pumps are connected to the heat exchanger, and the heat exchanger is connected to the spraying mechanism.

10. The exhaust gas treatment device for a waste gas system according to claim 9, characterized in that, The top of the two alkali circulation tanks is connected to a replenishment pipe. A mixer is installed on the pipeline between the heat exchanger and the two alkali circulation pumps. The replenishment pipe is connected to the mixer. An alkali pipe, a water supply pipe and a chlorine water pipe are connected to the mixer.

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