Integrated two-stage ozone tail gas treatment device

Abstract

The utility model discloses an integrated two-stage ozone tail gas treatment device which comprises a first-stage gas absorption area for removing volatile gaseous impurities and aerosol in tail gas, and a second-stage ozone catalytic decomposition area for catalytically decomposing ozone is connected above the first-stage gas absorption area; and a demisting layer is arranged between the first-stage gas absorption area and the ozone catalytic decomposition area. The integrated device is more compact in arrangement and small in occupied area, and the gas is short in flow path and small in pressure loss in the flowing process; the cross sections of the upper and lower functional areas are different, the gas velocities in the cylinder are different, target gas components are fully absorbed and removed at the lower part, and the poisoning risk to a catalyst at the upper part is avoided; the multiple layers of tower plates are matched with the flow guide plate, the liquid receiving tank and the overflow plate, so that target gas components are promoted to be fully absorbed and removed, and poisoning to a catalyst is further avoided; the gas inlet pipe of the gas absorption area is obliquely arranged, condensate water in tail gas cannot flow into the device, and the liquid level and concentration of absorption liquid are stably controlled.

Description

Technical Field

[0001] The utility model relates to an ozone tail gas treatment device, in particular to an integrated two-stage ozone tail gas treatment device. Background Art

[0002] Ozone is a strong oxidant and is widely used in the water treatment field, such as the pre-oxidation treatment of domestic drinking water and the advanced oxidation treatment of municipal sewage. In recent years, advanced oxidation technologies based on ozone have also been increasingly applied to the treatment of organic industrial wastewater, such as coking wastewater and petrochemical wastewater. During the ozone oxidation process, high-concentration ozone is added to the wastewater in the form of gas, and the added ozone cannot be completely consumed in the reaction, so that part of the ozone gas escapes from the wastewater. In actual engineering applications, the typical mass transfer efficiency of ozone is about 85-95%, and about 5-15% of the added ozone is lost in the tail gas. In addition, the composition of the incoming water of organic industrial wastewater is often complex, and volatile gaseous substances and aerosols in the raw water are also mixed into the ozone tail gas during the gas escape process. If the tail gas containing ozone and other volatile harmful gas components is not effectively collected and treated, it will cause harm to the surrounding environment and human body.

[0003] At present, for safety considerations, the tail gas generated by the ozone oxidation unit is mostly treated separately rather than mixed with other waste gases. The common ozone tail gas treatment devices on the market are also called ozone tail gas destruction devices, which are used to treat residual ozone. Most of their working principles are to decompose the residual ozone in the tail gas into oxygen by heating the tail gas or making the tail gas contact with a catalyst. The heating type tail gas destruction device adopts direct electric heating or indirect heating with other heat media, and its heating temperature needs to reach above 300°C, resulting in high energy consumption. The catalyst type tail gas destruction device is filled with solid catalyst in the device cavity, and ozone decomposition is realized after gas-solid contact. It has high requirements for the activity of the catalyst. Water vapor carried in the tail gas is likely to cause the catalyst to deactivate, and the catalyst needs to be replaced regularly. In order to extend the service life of the catalyst, a common method is to set a heating module in the tail gas destruction device to heat the tail gas to avoid the catalyst from getting damp.

[0004] The existing ozone tail gas destruction devices on the market have a single function and can only deal with the ozone component in the tail gas, and cannot deal with other volatile gaseous substances and aerosols and other gas pollutants. At the same time, gaseous substances such as sulfur-containing compounds and halogenated compounds emitted from some industrial wastewaters will cause ozone catalyst poisoning and reduce its catalytic activity, resulting in low ozone catalytic decomposition efficiency. Due to the process requirement of synchronously treating ozone and other volatile gaseous pollutants, it is necessary to connect the existing ozone tail gas destruction equipment and the waste gas treatment equipment for other gaseous pollutants in series, but this method has a long process pipeline, many gas pressure drops, and a large overall floor area of the equipment. Content of the Utility Model

[0005] Purpose of the utility model: The purpose of the present utility model is to avoid the influence of volatile substances or aerosols in the waste gas on ozone decomposition and simplify the treatment equipment, and provide an integrated two-stage ozone tail gas treatment device.

[0006] Technical solution: The integrated two-stage ozone tail gas treatment device described in the present utility model includes a primary gas absorption zone for removing volatile gaseous impurities and aerosols in the tail gas, and a secondary ozone catalytic decomposition zone for catalytically decomposing ozone is connected above it; the primary gas absorption zone includes an absorption cylinder, an intake pipe for ozone waste gas is provided at the lower end of the absorption cylinder, a liquid inlet for the absorption liquid for absorbing volatile gaseous substances or aerosols in the waste gas is provided at the upper end of the absorption cylinder, multiple trays are arranged between the intake pipe and the liquid inlet in the absorption cylinder, and a liquid outlet is provided at the bottom of the absorption cylinder; the secondary ozone catalytic decomposition zone includes a catalytic cylinder, and a catalytic layer and an exhaust pipe are sequentially arranged in the catalytic cylinder from bottom to top.

[0007] Further, the cross-sectional area of the primary gas absorption zone is greater than or equal to twice the cross-sectional area of the ozone catalytic decomposition zone, so that the gas velocity in the lower functional zone is lower than the gas velocity in the upper cylinder, and the tail gas can fully contact and absorb the volatile substances or aerosols in it with the absorption liquid before entering the catalytic decomposition zone, avoiding bringing them into the catalytic decomposition zone and affecting the catalytic decomposition efficiency of ozone and the damage to the catalyst.

[0008] Further, a demisting layer is provided between the two, and the demisting layer is a baffle type or wire mesh type demister. The vaporized liquid carried by the gas is intercepted here and then continues to flow upward to the secondary ozone catalytic decomposition zone, while the condensed liquid falls back into the primary gas absorption zone.

[0009] Further, the number of trays is not less than two, and its form is orifice plate type, bubble cap plate type or valve plate type. Liquid receiving troughs are arranged at one end of adjacent two trays relatively, and a flow guiding plate for introducing the upper liquid into this layer is provided above the liquid receiving trough. The absorption liquid is guided by the flow guiding plate to flow through multiple trays in sequence from the liquid inlet to increase the contact time and area between the absorption liquid and the tail gas, and thoroughly absorb the volatile substances or aerosols in the tail gas; the liquid receiving trough avoids the absorption liquid directly falling on the tray and generating fluid impact, affecting the residence and distribution of the absorption liquid on the tray and further affecting the removal efficiency of the volatile substances or aerosols in the tail gas.

[0010] Further, an overflow plate is arranged at one end of the tray opposite to the liquid receiving trough, so as to retain a certain amount of absorption liquid on the tray and further increase the removal efficiency of the volatile substances or aerosols in the tail gas.

[0011] Further, the intake pipe is arranged obliquely upward from outside to inside, so that the condensed water in the tail gas will not flow into the device, the liquid level and concentration of the absorption liquid are more stable, and the absorption efficiency of the absorption liquid is improved.

[0012] Furthermore, a liquid level gauge is provided on the absorption cylinder to facilitate monitoring the liquid level of the absorption liquid.

[0013] Furthermore, a support plate for supporting the packing is provided in the catalyst layer of the secondary ozone catalytic decomposition zone, and granular packing is placed thereon; the support plate is a perforated plate, and the aperture of the perforated plate is smaller than the particle size of the packing.

[0014] Furthermore, a heating device is connected to the catalyst layer of the secondary ozone catalytic decomposition zone.

[0015] Furthermore, the catalyst layer of the secondary ozone catalytic decomposition zone includes a preheating packing layer and a catalyst packing layer from top to bottom. The preheating packing layer is composed of gravel, and the catalyst packing layer is composed of manganese dioxide or copper oxide.

[0016] Working principle: Absorption liquids of different types and concentrations are configured according to the components of the tail gas and enter the integrated two-stage ozone tail gas treatment device through the liquid inlet. The ozone-containing tail gas first passes through the condensate water tank and then enters the first-stage gas absorption zone of the integrated two-stage ozone tail gas treatment device through the inlet pipe. In this zone, the gas flows from bottom to top, and the absorption liquid flows from top to bottom. The two undergo countercurrent contact at the tray of each layer. The absorbable components in the tail gas are absorbed by the absorption liquid and continue to flow upward into the demisting layer. The absorption liquid that has absorbed the gaseous substances continues to fall until the bottom of the device, and then passes through the outlet at the bottom and is circulated to the inlet through the circulating pump for cyclic absorption. When the absorption liquid needs to be replaced, part of the old absorption liquid is discharged by switching the valve on the circulating liquid pipeline, and then new absorption liquid is replenished. In the ozone catalytic decomposition zone, the gas containing water vapor is removed by heating. The dry gas contacts the solid catalyst in the catalyst layer, and the ozone component is decomposed into oxygen. Finally, the treated gas is discharged through the exhaust pipe.

[0017] Beneficial effects: Compared with the prior art, the present utility model has the following advantages: 1. The integrated device is more compactly arranged and occupies a small area, eliminating the pipelines and valves between the separate two-stage devices. The gas has a short flow path and small pressure loss during the flowing process; 2. Due to the cross-sectional difference between the upper and lower functional zones, the gas velocity in the lower absorption zone is lower than that in the upper catalytic decomposition zone, enabling the target gas components to have sufficient residence time to be fully absorbed and removed in the lower part, avoiding the risk of poisoning the catalyst; 3. The multi-layer trays are combined with the flow guiding plate, liquid receiving tank, and overflow plate to promote the full absorption and removal of the target gas components, further avoiding the risk of poisoning the upper catalyst; 4. The inlet pipe of the gas absorption zone is inclined, so that the condensate water in the tail gas will not flow back into the device, stably controlling the liquid level and concentration of the absorption liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a structural schematic diagram of the present utility model;

[0019] Figure 2 This is a schematic diagram of the use of the present utility model. Specific embodiments

[0020] The technical solution of the present utility model will be further described below in conjunction with the accompanying drawings.

[0021] As Figure 1 shown, the integrated two-stage ozone tail gas treatment device includes a primary gas absorption zone for removing volatile gaseous impurities and aerosols in the tail gas. A secondary ozone catalytic decomposition zone for catalytically decomposing ozone is connected above it. The cross-sectional area of the primary gas absorption zone is equal to twice the cross-sectional area of the ozone catalytic decomposition zone (it can also be greater than twice the cross-sectional area of the ozone catalytic decomposition zone according to the requirements of tail gas treatment efficiency). A demisting layer 207 is provided between the two, and the demisting layer 207 is a baffle type or wire mesh type demister. The primary gas absorption zone includes an absorption cylinder 2. An inlet pipe 201 for ozone-containing waste gas is provided at the lower end of the absorption cylinder 2, and the inlet pipe 201 is inclined upward from the outside to the inside; an absorption liquid inlet 202 for absorbing volatile substances or aerosols in the waste gas is provided on the absorption cylinder 2; two layers of trays 205 are arranged between the inlet pipe 201 and the inlet 202 in the absorption cylinder 2 (the trays 205 can be selected as orifice plates, bubble cap plates or valve plates according to actual needs, and the number of layers is set to two or more). A liquid receiving trough 204 is arranged at one end of two adjacent trays 205 relatively, and an overflow plate 206 is arranged at the other end. A deflector 203 for introducing the upper liquid into this layer is provided above the liquid receiving trough 204; the inlet 202 is arranged above the liquid receiving trough 204 of the first layer of tray 205. A liquid level gauge 212 is provided on the absorption cylinder 2, and a liquid outlet 213 and a support frame 216 are provided at the bottom. The secondary ozone catalytic decomposition zone includes a catalytic cylinder 3. A catalytic layer 209 and an exhaust pipe 211 are arranged in the catalytic cylinder 3 in sequence from bottom to top. A manhole 215 is provided on the side wall of the catalytic layer 209, which is convenient for initial installation or replacement of the packing; the catalytic layer 209 is provided with a porous support plate 217 for supporting the packing, and a granular catalyst packing layer 210 is placed thereon (a gravel packing can also be used as a preheating packing layer 208 below the catalyst packing layer 210 according to production requirements). The aperture of the support plate 217 is smaller than the particle size of the packing; the component of the catalyst packing layer 210 is a copper oxide or manganese oxide type catalyst packing, and a heating device 214 is arranged in the catalyst packing layer 210: for small-scale gas volume conditions, when the diameter of the cylinder body of the secondary ozone catalytic decomposition zone does not exceed 150 mm, an external heating method is adopted, such as a heating jacket; for conditions where the diameter of the cylinder body is greater than 150 mm, an internal heating method is adopted, such as a heating pipe.

[0022] As Figure 2As shown in the figure, during use, the tail gas A first passes through the inlet 101 of the condensate water tank 1 and enters the condensate water in the tank. Most of the water vapor condenses here and is collected in the tank. After the liquid level in the tank reaches a certain height, it is discharged through the automatic drain valve 103. The tail gas A after water removal passes through the outlet pipe 102 of the condensate water tank 1 and enters the absorption cylinder 2 of the integrated two-stage ozone tail gas treatment device through the inlet pipe 201 of the integrated two-stage ozone tail gas treatment device, and the tail gas flows from bottom to top. Open the valves 402 and 403 and start the circulation pump 5. The absorption liquid B in the absorption liquid tank 4 enters the integrated two-stage ozone tail gas treatment device from the liquid inlet 202, and under the action of gravity, it falls along the flow guide plate 203 into the liquid receiving tank 204 and flows through the tray 205. The two fluids undergo countercurrent mass transfer at the tray 205. The target gas components in the tail gas A are absorbed by the absorption liquid B and then continue to flow upward into the demisting layer 207. The absorption liquid continues to flow to the overflow plate 206 and continues to fall along the flow guide plate 203 until the bottom of the device, and is discharged through the outlet 213 at the bottom. Open the valve 401, close the valve 402, and the circulating absorption liquid C continues to circulate to the liquid inlet 202 through the absorption liquid circulation pump 5 for circulating absorption. The tail gas A after absorption treatment passes through the demisting layer 207. The vaporized liquid carried by the gas is intercepted here and falls back to the primary gas absorption area. The gas continues to flow upward to the secondary ozone catalytic decomposition area, is heated and dried by the heating device 214 through the catalytic layer 209, and is fully contacted with the catalyst to decompose into oxygen. The treated gas E is discharged through the exhaust pipe 211 and can be recycled. When the circulating absorption liquid C is recycled a certain number of times and the absorption effect is greatly reduced, close the valve 403, open the valve 404 to discharge part of the waste absorption liquid D until the liquid level in the absorption cylinder 2 reaches the low liquid level set by the liquid level gauge 212, then close the valves 401 and 404, open the valves 402 and 403 to supplement new absorption liquid B into the gas absorption area until the liquid level in the absorption cylinder 2 reaches the working liquid level height set by the liquid level gauge 212, then open the valve 401 and close the valve 402, and recycle the new absorption liquid B again to continue treating the ozone-containing tail gas A.

Claims

1. An integrated two-stage ozone tail gas treatment device, characterized in that, It includes a primary gas absorption zone for removing volatile gaseous impurities and aerosols in the tail gas, and a secondary ozone catalytic decomposition zone for catalytically decomposing ozone is connected above it; the primary gas absorption zone includes an absorption cylinder (2), an inlet pipe (201) for ozone waste gas is provided at the lower end of the absorption cylinder (2), and a liquid inlet (202) for the absorption liquid used to absorb volatile gaseous substances or aerosols in the waste gas is provided at the upper end. A plurality of trays (205) are arranged between the inlet pipe (201) and the liquid inlet (202) in the absorption cylinder (2), and a liquid outlet (213) is provided at the bottom of the absorption cylinder (2); the secondary ozone catalytic decomposition zone includes a catalytic cylinder (3), and a catalytic layer (209) and an exhaust pipe (211) are sequentially arranged in the catalytic cylinder (3) from bottom to top.

2. The integrated two-stage ozone tail gas treatment device according to claim 1, wherein, The cross-sectional area of the primary gas absorption zone is greater than or equal to twice the cross-sectional area of the ozone catalytic decomposition zone.

3. The integrated two-stage ozone tail gas treatment device according to claim 1, wherein A demisting layer (207) is provided between the primary gas absorption zone and the secondary ozone catalytic decomposition zone.

4. The integrated two-stage ozone tail gas treatment device according to claim 1, wherein The number of trays (205) is not less than two; receiving troughs (204) are arranged oppositely at one end of adjacent two trays (205), and a baffle (203) for introducing the upper liquid into this layer is provided above the receiving troughs (204).

5. The integrated two-stage ozone tail gas treatment device according to claim 4, characterized in that, An overflow plate (206) is arranged at one end of the tray (205) opposite to the receiving trough (204).

6. The integrated two-stage ozone tail gas treatment device according to claim 1, wherein The inlet pipe (201) is arranged obliquely upward from outside to inside.

7. The integrated two-stage ozone tail gas treatment device according to claim 1, wherein, The absorption cylinder (2) is provided with a liquid level gauge (212).

8. The integrated two-stage ozone tail gas treatment device according to claim 1, characterized in that, In the catalytic layer (209) of the secondary ozone catalytic decomposition zone, a support plate (217) for supporting the packing is provided, and granular packing is placed thereon; the support plate (217) is a perforated plate, and the hole diameter of the perforated plate is smaller than the particle size of the packing.

9. The integrated two-stage ozone tail gas treatment device according to claim 1, characterized in that The catalytic layer (209) of the secondary ozone catalytic decomposition zone is connected with a heating device (214).

10. The integrated two-stage ozone tail gas treatment device according to claim 1, characterized in that, The catalytic layer (209) of the secondary ozone catalytic decomposition zone includes a preheating packing layer (208) and a catalyst packing layer (210) from top to bottom. The component of the preheating packing layer (208) is gravel, and the component of the catalyst packing layer (210) is manganese dioxide or copper oxide.

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