Packed scrubbing tower and scrubbing method

Abstract

The application discloses a filler washing tower and a washing method, and relates to the technical field of VOCs exhaust gas washing treatment. The filler washing tower comprises a washing liquid pipe which is arranged at the central position of the washing tower and vertically extends, and is used for receiving washing liquid from outside the tower; the washing liquid pipe is provided with a rotatable pipe section at the corresponding position of the filler layer; a spray pipe assembly is composed of a plurality of spray pipes with different lengths and communicates with the rotatable pipe section; the spray port of each spray pipe is arranged at the pipe end; the spray pipes are arranged in a circumferential interval along the rotatable pipe section and are tangent to the rotatable pipe section; the spray pipes with different lengths drive the rotatable pipe section to rotate through reaction force when spraying washing liquid, and form annular partition coverage of the washing liquid to the filler layer. The application realizes the rotation of the spray pipe through the spraying of the washing liquid, and realizes the annular partition coverage of the spraying, so that water saving can be realized while the gas-liquid mass transfer efficiency is ensured, and external power consumption is not needed.

Description

Technical Field

[0001] This invention relates to the field of environmental waste gas treatment technology, and in particular to a water-saving packed scrubbing tower and scrubbing method. Background Technology

[0002] Petroleum processing, chemical industries, and other industries generate large amounts of VOCs (volatile organic compounds) during production and storage, which can generally be divided into organized and unorganized emissions. Unorganized VOC emissions refer to the irregular emission of waste gas without passing through exhaust stacks, such as wastewater treatment plant exhaust, exhaust from volatile organic liquid storage tanks, exhaust from volatile organic liquid loading operations, and exhaust from acidic water tanks, sewage tanks, sludge oil tanks, and intermediate oil tanks. If these unorganized emissions are not effectively treated, they will seriously pollute the surrounding environment and affect the health of workers; therefore, they must be properly sealed off and centrally treated to meet emission standards.

[0003] Washing-catalytic oxidation and washing-adsorption are common methods for VOCs waste gas treatment in recent years. VOCs waste gas first enters a washing tower to remove sludge, droplets, and water-soluble pollutants such as hydrogen sulfide and aminomethanethiol. The washed waste gas is then sent to subsequent catalytic oxidation or adsorption units for further purification. The washing tower is a key piece of equipment for achieving efficient waste gas washing. Based on the internal structure of its components, washing towers can be divided into packed towers and plate towers. A packed tower is a differential contact type gas-liquid mass transfer device, using packing as the basic component for gas-liquid contact and mass transfer. The liquid flows from top to bottom within the packing, while the gas flows continuously from bottom to top in a countercurrent manner. Compared to plate towers, packed towers have the advantages of simple structure, high mass transfer efficiency, and low pressure drop.

[0004] Existing packed scrubbing towers include energy-saving and water-saving spray scrubbing towers. For example, Chinese patent CN215539754U discloses a high-efficiency, energy-saving, and water-saving spray scrubbing tower, including an air inlet, an air outlet, a spray device, a packing layer, a circulating water tank, and spray pipes. By setting multiple air inlets, the height of the main body and water distribution pipes is reduced, the net head of the variable frequency spray pump is reduced, and the power consumption of the spray pump is saved. The high-efficiency nozzles are movably hinged to the spray frame. The high-efficiency nozzles on the outside of the spray frame can adjust the spray direction according to the working environment, resulting in a more concentrated spray area and higher efficiency. It also avoids the waste of chemical solution by spraying it onto the inner wall of the main body, which would prevent it from contacting the exhaust gas. However, this solution requires a large number of nozzles, which is difficult to install and prone to clogging, which is not conducive to the stable operation of the scrubbing tower. In addition, since an external spray pump is used, a certain amount of power consumption is still required.

[0005] The aforementioned existing technologies require continuous spraying to ensure efficient washing of waste gas within the packed tower, which places certain demands on the amount of liquid used for washing and results in significant water waste. Insufficient washing liquid can lead to problems affecting mass transfer efficiency, such as spray gaps during liquid spraying, wall flow phenomena when the liquid flows downwards along the packing, and the packing becoming easily clogged by contaminants after the washing tower has been operating for a period of time.

[0006] Therefore, there is an urgent need for a water-saving packed washing tower and washing method that can save water and eliminate the need for external power consumption.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a water-saving packed scrubbing tower and scrubbing method. The rotation of the spray pipe is achieved by spraying the scrubbing liquid, and the annular zone of the spray covers the area. While ensuring gas-liquid mass transfer efficiency, water saving can be achieved without external power consumption.

[0009] To achieve the above objectives, according to a first aspect of the present invention, a packed scrubbing tower is provided for scrubbing VOCs waste gas, comprising: a scrubbing liquid pipe, which is installed at the axial position of the scrubbing tower and extends vertically for receiving scrubbing liquid from outside the tower; the scrubbing liquid pipe is provided with a rotatable pipe section at a corresponding position in the packing layer; a spray pipe assembly, which consists of multiple spray pipes of different lengths and is connected to the rotatable pipe section, with the spray nozzle of each spray pipe located at the end of the pipe; the spray pipes are arranged at intervals along the circumference of the rotatable pipe section and are all tangent to the rotatable pipe section; when the spray pipes of different lengths spray the scrubbing liquid, the rotatable pipe section is driven to rotate by the reaction force, forming an annular partition coverage of the packing layer by the scrubbing liquid.

[0010] Furthermore, in the above technical solution, the length of the spray pipes of varying lengths can gradually increase in a clockwise or counterclockwise direction, and the number of annular zones corresponds to the number of spray pipes.

[0011] Furthermore, in the above technical solution, the length difference between two adjacent spray pipes can be the ratio of the main body radius of the packed washing tower to the number of spray pipes in each group.

[0012] Furthermore, in the above technical solution, the rotatable pipe section may be provided with a first bearing and a second bearing at both ends.

[0013] Furthermore, in the above technical solution, the spray pipe assembly may include an upper spray pipe assembly and a lower spray pipe assembly. The upper spray pipe assembly is located above the filler layer and each spray pipe is inclined downwards, while the lower spray pipe assembly is located below the filler layer and each spray pipe is inclined upwards.

[0014] Furthermore, in the above technical solution, the tilt angle of each spray pipe can be determined according to the length of the spray pipe and the distance between the end of the pipe and the surface of the filler, specifically 15° to 75°.

[0015] Furthermore, in the above technical solution, the distance between the upper surface of the packing layer and the end of the spray pipe in the upper spray pipe assembly is set as L1, and the distance between the lower surface of the packing layer and the end of the spray pipe in the lower spray pipe assembly is set as L2, preferably L1 is greater than L2. Wherein, L1 can be 0.1 to 0.4 times the radius R of the tower body, and L2 can be 0.05 to 0.2 times the radius R of the tower body.

[0016] Furthermore, in the above technical solution, an annular baffle may be provided on the outer edge of the packing layer. The annular baffle includes: an arc-shaped part, which is located on the upper edge of the packing layer and extends upward toward the inner wall of the tower, with the upper edge of the arc-shaped part being higher than the end of the upper spray pipe assembly; and a straight edge part, which extends downward toward the inner wall of the tower from the lower edge of the arc-shaped part, with the angle between the straight edge and the upper edge of the packing layer being greater than 90 degrees.

[0017] Furthermore, in the above technical solution, the rotatable pipe section may also be provided with a third bearing and a fourth bearing. The third bearing, the first bearing, the fourth bearing, and the second bearing respectively divide the rotatable pipe section into two relatively independent sections (the two sections can rotate independently). The upper section is used to install the upper spray pipe assembly, and the lower section is used to install the lower spray pipe assembly.

[0018] Furthermore, in the above technical solution, a rotating blade can be provided below the lower spray pipe assembly. Driven by the VOCs exhaust gas running from bottom to top, the rotating blade can assist in driving the lower spray pipe assembly to rotate, so that the rotation speed of the lower spray pipe assembly is higher than that of the upper spray pipe assembly.

[0019] Furthermore, in the above technical solution, both the washing liquid pipe and the spray pipe assembly can be made of metal; the packing layer can be filled with structured packing or bulk packing, the structured packing can be wire mesh corrugated packing or plate corrugated packing, etc., the bulk packing can be open-hole ring packing or saddle packing, etc., and the packing material can be metal or ceramic, etc.

[0020] Furthermore, in the above technical solution, the bottom of the washing liquid pipe can be supported by a support rod, which can be fixedly connected to the inner wall of the tower.

[0021] Furthermore, in the above technical solution, a regulating valve for adjusting the flow rate in the washing liquid pipe can be installed at the top of the packed washing tower.

[0022] Furthermore, in the above technical solution, a demister layer may be provided in the packed washing tower, which is located above the packing layer and at the fixed section of the washing liquid pipe.

[0023] Furthermore, in the above technical solution, a spray pipe assembly can be provided at the corresponding position of each filler layer.

[0024] To achieve the above objectives, according to a second aspect of the present invention, a washing method is provided for washing VOCs waste gas, comprising the following steps: A. Introducing a washing liquid with an adjustable flow rate that flows downwards into a washing liquid pipe, and then spraying it out from the end of a spray pipe assembly on a rotatable pipe section disposed on the washing liquid pipe; B. The reaction force of the sprayed washing liquid on the spray pipe drives the spray pipe assembly to rotate, and the washing liquid sprayed from the spray pipes of different lengths in each spray pipe assembly forms an annular partition covering on the packing layer; C. The washing liquid that forms a uniform coverage of the packing layer comes into full contact with the VOCs waste gas flowing upwards in the packing layer and completes gas-liquid mass transfer.

[0025] Furthermore, in the above technical solution, step B may further include: the washing liquid sprayed by the upper spray pipe assembly covers the upper surface of the filler layer in sections, and the washing liquid sprayed by the lower spray pipe assembly covers the lower surface of the filler layer in sections, so as to ensure that the filler layer is quickly and completely wetted.

[0026] Furthermore, in the above technical solution, the rotation speed of the spray pipe assembly can be changed by adjusting the flow rate of the washing liquid, thereby adjusting the impact position of the washing liquid on the filler layer.

[0027] Furthermore, in the above technical solution, the flow rate adjustment can be specifically as follows: the liquid-to-gas ratio of the packed scrubbing tower is 2-3 L / Nm³. 3 The washing liquid is circulated every 20 minutes. The average flow rate of the washing liquid in each cycle is Q. Within a single cycle, the flow rate of the washing liquid gradually increases from 0.5Q to 0.7Q to 1.3Q to 1.5Q or gradually decreases from 1.3Q to 1.5Q to 0.5Q to 0.7Q.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1) By setting a rotatable pipe section on the washing liquid pipe and setting spray pipes of different lengths evenly spaced along the tangential direction of the rotatable pipe section on the rotatable pipe section, the washing liquid can achieve annular coverage of different ranges of the filler layer. In this way, the filler layer can be fully covered with less washing liquid, avoiding the waste of water resources.

[0030] 2) This invention uses a pair of spray pipe assemblies, but the upper and lower spray pipe assemblies of each pair are arranged in opposite directions, so that the upper and lower surfaces can be evenly covered. This ensures that the packing layer is quickly and completely wetted, and the washing liquid forms a liquid film on all the wire mesh, corrugations or small holes on the surface and inside of the packing layer, which effectively enhances the mass transfer efficiency between the washing liquid and the exhaust gas. At the same time, the spray speed and direction of the washing liquid can be adjusted by the flow rate of the washing liquid, and the spray pipe assembly can be continuously changed with the rotation. The impact position on the packing layer can also be continuously changed, which is more conducive to the discharge of dirt in the packing layer and avoids clogging.

[0031] 3) According to the inventor's experimental research, when the distance L1 between the upper surface of the packing layer and the end of the spray pipe in the upper spray pipe assembly is 0.1 to 0.4 times the radius R of the tower body, and the distance L2 between the lower surface of the packing layer and the end of the spray pipe in the lower spray pipe assembly is 0.05 to 0.2 times the radius R of the tower body, the overall wetting effect of the packing layer is optimal.

[0032] 4) By setting an annular baffle, the upper edge of the arc-shaped part of the annular baffle is higher than the end of the upper spray pipe assembly, which can ensure that the washing liquid sprayed from the spray pipe can cover the area inside the annular baffle, thereby guiding the splashed washing liquid to the packing area; the angle between the straight edge of the straight edge and the upper edge of the packing layer is greater than 90 degrees, which can effectively reduce the influence of wall flow and avoid droplet short circuit caused by wall flow, which would reduce the gas-liquid mass transfer efficiency.

[0033] 5) This invention utilizes the reaction force of the washing liquid sprayed from the spray pipe to make the spray assembly rotate automatically, eliminating the need for an additional motor and saving energy; it also has a simple structure, low pressure drop, and low manufacturing and operating costs, and can be easily operated through automatic or manual adjustment via the washing liquid regulating valve.

[0034] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the first embodiment of the packed scrubbing tower of the present invention.

[0036] Figure 2 This is a top view of the packing washing tower of the present invention (showing the arrangement of the upper spray pipe assembly and the spray range).

[0037] Figure 3 This is a schematic diagram of the structure of the washing liquid pipe inside the packing washing tower of the present invention (showing the inclined arrangement of the spray pipes in the upper spray pipe assembly and the lower spray pipe assembly).

[0038] Figure 4 This is a schematic diagram of the structure of the second embodiment of the packed washing tower of the present invention.

[0039] Explanation of key figure labels:

[0040] 100-Packed scrubbing tower, 101-Scrubbing liquid inlet, 102-Scrubbing liquid outlet, 103-VOCs exhaust gas inlet, 104-Exhaust gas outlet, 105-Support rod;

[0041] 1-Spray pipe assembly, 10-Supporting rib, 11-Upper spray pipe assembly, 11a-First upper spray pipe, 11b-Second upper spray pipe, 11c-Third upper spray pipe, 11d-Fourth upper spray pipe, 12-Lower spray pipe assembly, 12a-First lower spray pipe, 12b-Second lower spray pipe, 12c-Third lower spray pipe, 12d-Fourth lower spray pipe; 2-Washing liquid pipe, 20-Flow regulating valve, 21-Rotable pipe section, 210-Rotating blade, 211-Rotable upper pipe section, 212-Rotable lower pipe section, 22a-First bearing, 22b-Second bearing, 22c-Third bearing, 22d-Fourth bearing, 3-Packaging layer, 31-Packaging layer support, 4-Annular baffle, 41-Arc-shaped part, 42-Straight edge part, 5-Demisting layer. Detailed Implementation

[0042] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0043] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0044] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0045] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0046] Example 1

[0047] like Figures 1 to 3 As shown, this invention provides an embodiment of a packed scrubbing tower 100 for the scrubbing treatment of VOCs waste gas, comprising at least a scrubbing liquid pipe 2 and a spray pipe assembly 1. The scrubbing liquid pipe 2 is installed vertically at the axial position of the packed scrubbing tower 100 to receive scrubbing liquid from outside the tower. Its bottom is supported by a support rod 105, which is fixedly connected to the inner wall of the tower. A rotatable pipe section 21 is provided at a corresponding position of the packing layer 3 of the scrubbing liquid pipe 2. The spray pipe assembly 1 consists of multiple spray pipes of varying lengths and communicates with the rotatable pipe section 21. It should be noted that the spray pipe assembly 1 can have one set of spray pipes (not shown in the figure) above each packing layer 3, or it can have one set of upper spray pipes above each packing layer 3 and one set of lower spray pipes below each packing layer 3. The spray nozzle of each spray pipe is located at the end of the pipe. The spray pipes are arranged circumferentially around the rotatable pipe section 21 and are all tangent to the rotatable pipe section 21 (see reference). Figure 2 The spray pipes of varying lengths, when spraying the washing liquid, drive the rotatable pipe sections to rotate in the opposite direction through reaction force, forming an annular zoned coverage of the washing liquid on the packing layer 3 (see reference). Figure 2 (Areas A, B, C, and D are indicated by the dashed lines). Each group of spray pipes can have at least 3 spray pipes evenly spaced, preferably 4-8. Figures 1 to 3 The embodiment uses four spray pipes, which cover the aforementioned four annular zones.

[0048] This invention achieves circumferential coverage of the filler layer by setting a rotatable pipe section on the washing liquid pipe and setting spray pipes of varying lengths at uniform intervals along the tangential direction of the rotatable pipe section on the rotatable pipe section. In this way, the filler layer can be fully covered with less washing liquid, thus avoiding the waste of water resources.

[0049] Furthermore, preferably but not limitingly, the lengths of the spray pipes of varying lengths can be set to gradually increase in a clockwise or counterclockwise direction (see reference). Figure 2 The number of annular zones corresponds to the number of sprinkler pipes. Specifically, with Figure 1Taking the upper and lower sets of spray pipes as an example, the first upper spray pipe 11a covers area A, the second upper spray pipe 11b covers area B, the third upper spray pipe 11c covers area C, and the fourth upper spray pipe 11d covers area D (i.e., the four areas on the upper surface of the filler layer). Longer spray pipes can be reinforced with support ribs 10. Similarly, the first lower spray pipe 12a covers area A, the second lower spray pipe 12b covers area B, the third lower spray pipe 12c covers area C, and the fourth lower spray pipe 12d covers area D (i.e., the four areas on the lower surface of the filler layer).

[0050] Further, preferably but not limitingly, the length difference between two adjacent spray pipes is the ratio of the main body radius of the packed scrubbing tower to the number of spray pipes in each group. Specifically, the length of each spray pipe in each group is determined based on the main body radius R of the tower and the number of spray pipes in each group m, and the length difference between two adjacent spray pipes is preferably R / m.

[0051] Furthermore, such as Figure 1 , 3 As shown, in order to ensure that only the rotatable pipe section 21 in the washing liquid pipe 2 can rotate, a first bearing 22a and a second bearing 22b are provided at both ends of the rotatable pipe section 21 to ensure that only this pipe section and the spray pipes mounted on it can rotate, while other pipe sections remain stationary. Based on this, the spray pipe assembly 1 preferably includes an upper spray pipe assembly 11 and a lower spray pipe assembly 12. The upper spray pipe assembly 11 is located above the packing layer 3, and each spray pipe is inclined downwards (see reference). Figure 3 The lower spray pipe assembly is located below the packing layer 3, and each spray pipe is inclined upwards. Preferably, but not limitingly, the inclination angle of each spray pipe can be determined according to the length of the spray pipe and the distance between the pipe end and the packing surface, specifically 15° to 75°. This arrangement, where the spray pipe assemblies are arranged in pairs, but the upper and lower spray pipe assemblies of each pair are arranged in opposite directions, with all spray pipe outlets facing the outer surface of the packing layer (both the upper and lower surfaces can be evenly covered), ensures rapid and complete wetting of the packing layer. This allows the washing liquid to form a liquid film on the surface and inside the packing, at all the wire mesh, corrugations, or small holes, effectively enhancing the mass transfer efficiency between the washing liquid and the exhaust gas. The upper and lower spray pipe assemblies of this invention have the same number of spray pipes, and the lengths and included angles of the upper and lower spray pipes can correspond one-to-one or be slightly different, depending on actual needs. Further references Figure 1 Let L1 be the distance between the upper surface of the packing layer 3 and the end of the spray pipe in the upper spray pipe assembly 11, and L2 be the distance between the lower surface of the packing layer and the end of the spray pipe in the lower spray pipe assembly 12. Preferably, L1 is greater than L2 to ensure the washing liquid in the lower spray pipe assembly 12 has a good impact covering effect on the lower surface of the packing layer 3. Specifically, according to the inventors' experimental research, the overall wetting effect on the packing layer is optimal when L1 is 0.1 to 0.4 times the radius R of the tower body and L2 is 0.05 to 0.2 times the radius R of the tower body.

[0052] Further as Figure 1 As shown, an annular baffle 4 is provided on the outer edge of the packing layer 3. The annular baffle 4 includes an arc-shaped portion 41 and a straight edge portion 42. The arc-shaped portion 41 extends upward from the upper edge of the packing layer 3 toward the inner wall of the tower. The upper edge of the arc-shaped portion is higher than the end of the upper spray pipe assembly, which ensures that the washing liquid sprayed from the spray pipe can cover the area within the annular baffle. If it splashes onto the arc-shaped portion 41 of the baffle, it can be guided to the packing area. The straight edge portion 42 extends downward from the lower edge of the arc-shaped portion 41 toward the inner wall of the tower. The angle between the straight edge and the upper edge of the packing layer is greater than 90 degrees. This design can effectively reduce the influence of wall flow and avoid droplet short-circuiting caused by wall flow, which would reduce the gas-liquid mass transfer efficiency.

[0053] It should be noted that the packed scrubbing tower 100 can be equipped with multiple layers of packing 3, and each packing layer 3 can have corresponding positions equipped with Figures 1 to 3 The spray pipe assembly in the middle. Specifically, the washing liquid pipe 2 is equipped with one or n pairs of bearings, dividing the washing liquid pipe into 2n+1 sections. That is, when there is only one pair of bearings, the washing liquid pipe is divided into three sections from top to bottom: the washing liquid inlet section, the rotatable pipe section 21, and the washing liquid outlet section (i.e., Figures 1 to 3 (Illustrated embodiment); When there are n pairs (n ≥ 2) of bearings, the washing liquid pipe 2 is divided from top to bottom into a washing liquid inlet section, rotatable pipe sections 1 to n, and a washing liquid outlet section. The number of spray pipe assemblies is the same as the number of bearing pairs and the number of packing layers. With this implementation, the spray pipe assemblies above and below each packing layer can simultaneously spray washing liquid onto the packing layer 3, ensuring rapid and complete wetting of the packing layer 3, allowing the washing liquid to quickly form a liquid film on and inside the packing surface, enhancing the mass transfer efficiency between the washing liquid and the gas; simultaneously, the flow rate of the washing liquid can be adjusted (see...). Figure 1 The flow regulating valve 20 in the middle allows the spray speed of the washing liquid to change continuously with the rotation of the spray pipe assembly, and the impact position on the packing layer also changes continuously. This is more conducive to the discharge of dirt in the packing layer and avoids blockage.

[0054] Furthermore, both the washing liquid pipe 2 and the spray pipe assembly 1 of the present invention can be made of metal; the filler layer 3 can be filled with structured filler or bulk filler. The structured filler can be wire mesh corrugated filler or plate corrugated filler, and the bulk filler can be open-hole annular filler or saddle-shaped filler. The filler material can be metal or ceramic.

[0055] Furthermore, a demister layer 5 is provided above the uppermost packing layer 3 of the present invention (that is, the fixed pipe section above the uppermost rotatable pipe section). After the exhaust gas enters the tower body through the VOCs exhaust gas inlet 103, it undergoes gas-liquid mass transfer and washing through the packing layer, and is demisted by the demister layer 5 before being discharged from the exhaust gas outlet 104.

[0056] Example 2

[0057] like Figure 4 As shown, this invention provides another embodiment of a packed scrubbing tower. This embodiment 2 differs from embodiment 1 in that the rotatable pipe section is further equipped with a third bearing 22c and a fourth bearing 22d. The third bearing 22c, the first bearing 22a, the fourth bearing 22d, and the second bearing 22b further divide the rotatable pipe section into two relatively independent segments (each segment can rotate independently). The upper segment (i.e., the rotatable upper pipe section 211) is used to house the upper spray pipe assembly, and the lower segment (i.e., the rotatable lower pipe section 212) is used to house the lower spray pipe assembly. Further, preferably but not limitingly, a rotating blade 210 is provided below the lower spray pipe assembly in the lower segment. Driven by the upward-moving VOCs exhaust gas, the rotating blade assists in rotating the lower spray pipe assembly, allowing the lower spray pipe assembly to rotate at a higher speed than the upper spray pipe assembly. This achieves a stronger impact coverage of the lower spray pipe assembly on the lower surface of the packing layer, further improving the wetting speed of the scrubbing liquid on the packing.

[0058] When the packing layer has multiple layers (i.e., n layers), the washing liquid pipe is equipped with 2n pairs of bearings. The number of bearing pairs is twice the number of spray pipe assembly pairs. The number of spray pipe assembly pairs is the same as the number of packing layers, which will not be elaborated here.

[0059] Example 3

[0060] This invention provides a washing method using a scrubbing tower as described in Example 1 or Example 2. This method is used for the scrubbing treatment of VOCs waste gas and includes the following steps:

[0061] In step S101, a washing liquid with adjustable flow rate, flowing downwards, is introduced into the washing liquid pipe 2, and then sprayed out from the end of the spray pipe assembly 1 of the rotatable pipe section 21 located on the washing liquid pipe 2. Specifically, in this embodiment, the washing liquid inlet 101 is located at the top of the tower, and the washing liquid outlet 102 is located at the bottom of the tower, so that the washing liquid flows downwards, and the flow rate and velocity are adjusted by the flow regulating valve 20.

[0062] In step S102, the reaction force of the sprayed washing liquid on the spray pipes drives the spray pipe assembly 1 to rotate. The washing liquid sprayed from the spray pipes of varying lengths in each spray pipe assembly 1 forms an annular partitioned coverage on the packing layer 3. Preferably, but not limitingly, the washing liquid sprayed from the upper spray pipe assembly 11 can partitionedly cover the upper surface of the packing layer 3, and the washing liquid sprayed from the lower spray pipe assembly 12 can partitionedly cover the lower surface of the packing layer 3, ensuring rapid and complete wetting of the packing layer. During rapid wetting, the annular baffle between the packing layer 3 and the tower body can effectively reduce the influence of wall flow. Furthermore, the rotation speed of the spray pipe assembly 1 can be changed by adjusting the flow rate of the washing liquid, thereby adjusting the impact position of the washing liquid on the packing layer. Specifically, the liquid-to-gas ratio of the packed washing tower is 2-3 L / Nm³. 3The washing liquid is circulated every 20 minutes. The average flow rate of the washing liquid in each cycle is Q. Within a single cycle, the flow rate gradually increases from 0.5Q to 0.7Q to 1.3Q to 1.5Q, or gradually decreases from 1.3Q to 1.5Q to 0.5Q to 0.7Q. In this way, the flow direction and velocity of the washing liquid continuously change with the rotation of the spray assembly, and the impact position on the packing layer also continuously changes, which is beneficial for the discharge of dirt from the packing layer and prevents clogging.

[0063] In step S103, the washing liquid that uniformly covers the packing material comes into full contact with the VOCs waste gas flowing upwards within the packing layer, completing gas-liquid mass transfer. Specifically, the VOCs waste gas enters from the VOCs waste gas inlet 103 on the lower side wall of the tower and flows upwards. When passing through the packing layer, it comes into contact with the wetted droplets for gas-liquid mass transfer. When the packing layer has multiple layers, the final washing is completed through step-by-step contact. After washing, the waste gas is demisted and discharged from the waste gas outlet 104 located at the top of the tower.

[0064] The method of this embodiment 3 can achieve the same technical effect as embodiments 1 and 2, and will not be described again here.

[0065] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A filler washing column, characterized by The application relates to a washing treatment for VOCs exhaust gas, which comprises the following steps: a washing liquid pipe is arranged at the center of the washing tower and extends vertically to receive washing liquid from outside the tower; the washing liquid pipe is provided with a rotatable pipe section at the position corresponding to the packing layer; a spray pipe assembly is composed of a plurality of spray pipes with different lengths and communicates with the rotatable pipe section; the spray ports of the spray pipes are arranged at the pipe ends; the spray pipes are arranged at intervals in the circumferential direction of the rotatable pipe section and are tangent to the rotatable pipe section; the spray pipes with different lengths drive the rotatable pipe section to rotate by reaction force when the washing liquid is sprayed, so that the washing liquid covers the packing layer in the form of annular sub-zones; the spray pipe assembly comprises an upper spray pipe assembly and a lower spray pipe assembly; the upper spray pipe assembly is arranged above the packing layer and each spray pipe is inclined downward; the lower spray pipe assembly is arranged below the packing layer and each spray pipe is inclined upward; the rotatable pipe section is further divided into two relatively independent sections; the upper section is used for arranging the upper spray pipe assembly and the lower section is used for arranging the lower spray pipe assembly; a rotating blade is arranged below the lower spray pipe assembly of the lower section; under the driving action of the VOCs exhaust gas running from bottom to top, the rotating blade assists the rotation of the lower spray pipe assembly, so that the rotation speed of the lower spray pipe assembly is higher than that of the upper spray pipe assembly.

2. The filler washing column according to claim 1, characterized in that, The lengths of the spray pipes with different lengths gradually increase in the clockwise or counterclockwise direction; the number of the annular sub-zones corresponds to the number of the spray pipes.

3. The filler washing column according to claim 1, characterized in that, The length difference between two adjacent spray pipes is the ratio of the main radius of the packing washing tower to the number of each group of spray pipes.

4. The filler washing column according to claim 1, characterized in that, First and second bearings are arranged at the two ends of the rotatable pipe section.

5. The filler washing column according to claim 1, characterized in that, The inclination angle of each spray pipe is determined according to the length of the spray pipe and the distance between the pipe end and the packing surface, and is 15-75 degrees.

6. The filler washing column according to claim 5, characterized in that The distance between the upper surface of the packing layer and the pipe end of the upper spray pipe assembly is L1, and the distance between the lower surface of the packing layer and the pipe end of the lower spray pipe assembly is L2; L1 is greater than L2.

7. The filler washing column according to claim 6, characterized in that L1 is 0.1-0.4 times the main radius R of the tower, and L2 is 0.05-0.2 times the main radius R of the tower.

8. The filler washing column according to claim 1, characterized in that, An annular baffle is arranged at the outer edge of the packing layer and comprises: an arc-shaped part which extends upwards along the inner wall of the tower above the packing layer; the upper edge of the arc-shaped part is higher than the pipe end of the upper spray pipe assembly; a straight edge part which extends downwards along the inner wall of the tower from the lower edge of the arc-shaped part; the included angle between the straight edge and the upper edge of the packing layer is greater than 90 degrees.

9. The filler washing column according to claim 1, characterized in that, The rotatable pipe section is further provided with third and fourth bearings; the third and first bearings and the fourth and second bearings respectively divide the rotatable pipe section into two relatively independent sections.

10. The filler washing column according to claim 1, characterized in that, The washing liquid pipe and the spray pipe assembly are made of metal; the packing layer is filled with regular packing or bulk packing; the regular packing is wire mesh corrugated packing or plate corrugated packing; the bulk packing is in the form of open ring packing or saddle-shaped packing; the packing material is metal or ceramic.

11. The filler washing column according to claim 1, characterized in that The bottom of the washing liquid pipe is supported by a support rod which is fixedly connected to the inner wall of the tower.

12. The filler washing column according to claim 1, characterized in that, An adjusting valve is arranged at the top of the packing washing tower to adjust the flow in the washing liquid pipe.

13. The filler washing column according to claim 1, characterized in that, The filler washing tower is provided with a demisting layer above the filler layer at the fixed pipe section of the washing liquid pipe.

14. The filler washing column according to any one of claims 1 to 13, characterized in that The filler washing tower is provided with the spray pipe assembly at the corresponding position of each filler layer.

15. A washing method characterized by, The application discloses a filler washing tower for VOCs exhaust gas, which comprises a filler layer and a washing liquid pipe. A, the washing liquid with adjustable flow is introduced into the washing liquid pipe from top to bottom, and then sprayed from the end of the spray pipe assembly of the rotatable pipe section arranged on the washing liquid pipe; B, the reaction force of the sprayed washing liquid drives the rotation of the spray pipe assembly, and the washing liquid sprayed from the spray pipes with different lengths in each spray pipe assembly forms annular partition coverage on the filler layer; C, the washing liquid forming uniform coverage on the filler layer is fully contacted with the VOCs exhaust gas running from bottom to top in the filler layer and completes the gas-liquid mass transfer.

16. The washing method according to claim 15, wherein, The step B further comprises: the washing liquid sprayed by the upper spray pipe assembly partitions and covers the upper surface of the filler layer, and the washing liquid sprayed by the lower spray pipe assembly partitions and covers the lower surface of the filler layer, so that the rapid full immersion of the filler layer is ensured.

17. The washing method according to claim 15, wherein, The rotation speed of the spray pipe assembly is changed by adjusting the flow of the washing liquid, and then the impact position of the washing liquid on the filler layer is adjusted.

18. The washing method according to claim 17, wherein, The flow regulation is specifically: the liquid-gas ratio of the packing washing tower is 2-3 L / Nm 3 ; the washing liquid flow is circulated every 20 min, the average flow of each cycle is Q, and the flow of the washing liquid in a single cycle gradually increases from 0.5Q-0.7Q to 1.3Q-1.5Q or gradually decreases from 1.3Q-1.5Q to 0.5Q-0.7Q.

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