Packing washing tower and washing method

Abstract

The present invention discloses a filler washing tower and a washing method, the filler washing tower is used for washing treatment of VOCs waste gas, and the filler washing tower comprises: a washing liquid pipe which is arranged at the axis position of the washing tower in a penetrating manner, vertically extends and is used for receiving a washing liquid from the outside of the tower; the washing liquid pipe is provided with a rotatable pipe section at the corresponding position of the filler layer; the spraying pipe assembly is composed of a plurality of spraying pipes with different lengths and is communicated with the rotatable pipe section, and a spraying opening of each spraying pipe is formed in the tail end of the pipe; the spraying pipes are arranged at intervals in the circumferential direction of the rotatable pipe section and are tangent to the rotatable pipe section; the spraying pipes with different lengths drive the rotatable pipe section to rotate through counter-acting force when spraying out the washing liquid, and annular partition covering of the washing liquid on the packing layer is formed. Rotation of the spraying pipe is achieved through spraying of washing liquid, and through annular partition covering of spraying, water saving can be achieved while the gas-liquid mass transfer efficiency is guaranteed, and external power consumption is not needed.

Description

Technical Field

[0001] The invention relates to the technical field of environmentally friendly waste gas treatment, and in particular to a water-saving packed washing tower and a washing method. Background Art

[0002] Oil processing, chemical industry, etc. will emit a large amount of VOCs waste gas during production, storage and transportation, which can usually be divided into organized emissions and unorganized emissions. Unorganized emissions of VOCs waste gas refer to the irregular emission of waste gas without passing through the exhaust pipe, such as waste gas from sewage treatment plants, exhaust from volatile organic liquid storage tanks, exhaust from volatile organic liquid loading operations, and exhaust from acidic water tanks, sewage tanks, waste oil tanks, intermediate oil tanks, etc. For these unorganized exhaust gases, if effective methods are not adopted to deal with them, they will seriously pollute the surrounding environment and affect the health of workers. Therefore, they need to be properly sealed and centrally managed before they can meet emission standards.

[0003] Washing-catalytic oxidation and washing-adsorption are both common methods for VOCs waste gas treatment in recent years. VOCs waste gas first enters the washing tower to remove sludge droplets and water-soluble hydrogen sulfide, aminomethyl mercaptan and other pollutants in the waste gas. The washed waste gas is sent to the subsequent catalytic oxidation or adsorption unit for deep purification. The washing tower is a key equipment for achieving efficient washing of waste gas. According to the structure of the internal components of the washing tower, the washing tower can be divided into two types: packed tower and plate tower. The packed tower is a differential contact type gas-liquid mass transfer equipment, which uses packing as the basic component for gas-liquid contact and mass transfer. The liquid flows from top to bottom in the packing, and the gas flows from bottom to top in a continuous phase in countercurrent with the liquid. Compared with the plate tower, the packed tower has the characteristics of simple structure, high mass transfer efficiency and small pressure drop.

[0004] Existing packed scrubbers include energy-saving and water-saving spray scrubbers. For example, Chinese patent CN215539754U discloses an efficient, energy-saving and water-saving spray scrubber, including an air inlet, an air outlet, a spray device, a packing layer, a circulating water tank and a spray pipe. By setting multiple air inlets, the height of the main body and the water distribution pipe 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 nozzle is movably hinged on the spray rack. The high-efficiency nozzle on the outside of the spray rack can adjust the spray direction according to the working environment. The spray area is more concentrated and more efficient, and it can avoid the liquid medicine being sprayed on the inner wall of the main body, resulting in the inability to contact the exhaust gas and causing waste of liquid medicine. However, this solution requires the installation of more nozzles, which are unchanged and easy to clog, which is not conducive to the stable operation of the scrubber. In addition, due to the use of an external spray pump, a certain amount of power consumption is still required.

[0005] In order to ensure efficient washing of the exhaust gas in the packed tower, similar solutions in the above-mentioned prior art need to continuously spray, which has certain requirements on the amount of liquid used for washing, resulting in a large amount of water waste. If the amount of washing liquid is insufficient, some problems affecting mass transfer efficiency will occur, such as spray gaps when the liquid is sprayed, wall flow when the liquid flows downward along the packing, and the packing is easily blocked by pollutants after the washing tower has been working for a period of time.

[0006] Therefore, there is an urgent need for a water-saving packed scrubber and a scrubbing method that can save water while not requiring external electricity consumption.

[0007] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0008] The object of the present invention is to provide a water-saving packed washing tower and washing method, which realizes the rotation of the spray pipe by the injection of washing liquid and the annular partition coverage of the spray, thereby ensuring the gas-liquid mass transfer efficiency while achieving water saving and no external power consumption.

[0009] To achieve the above-mentioned purpose, according to the first aspect of the present invention, there is provided a packed washing tower for washing and treating VOCs waste gas, comprising: a washing liquid pipe, which is arranged at the axial position of the washing tower and extends vertically, and is used to receive washing liquid from outside the tower; the washing liquid pipe is provided with a rotatable pipe section at the corresponding position of the packing layer; a spray pipe assembly, which is composed of a plurality of spray pipes of different lengths and is connected to the rotatable pipe section, and the injection port of each spray pipe is arranged 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; the spray pipes of different lengths drive the rotatable pipe section to rotate through the reaction force when spraying washing liquid, so as to form an annular partitioned coverage of the packing layer by the washing liquid.

[0010] Furthermore, in the above technical solution, the lengths of the spray pipes of different lengths may gradually increase in a clockwise or counterclockwise direction, and the number of annular partitions corresponds to the number of spray pipes.

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

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

[0013] Furthermore, in the above technical solution, the spray pipe assembly may include an upper spray pipe assembly and a lower spray pipe assembly, wherein the upper spray pipe assembly is located above the packing layer and each spray pipe is inclined downward, and the lower spray pipe assembly is located below the packing layer and each spray pipe is inclined upward.

[0014] Furthermore, in the above technical solution, the inclination 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] Further, 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 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 L2, preferably L1 is greater than L2. Among them, 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, and the annular baffle includes: an arc-shaped portion, which is provided on the upper edge of the packing layer and extends upward toward the inner wall of the tower, and the upper edge of the arc-shaped portion is higher than the tube end of the upper spray pipe assembly; a straight edge portion, which extends downward toward the inner wall of the tower from the lower edge of the arc-shaped portion, and the angle between the straight edge and the upper edge of the packing layer is 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, and the third bearing and 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), wherein the upper section is used to set the upper spray pipe assembly, and the lower section is used to set the lower spray pipe assembly.

[0018] Furthermore, in the above technical solution, a rotating blade may be provided under the lower spray pipe assembly of the lower section. Driven by the VOCs exhaust gas running from bottom to top, the rotating blade may 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 scheme, the washing liquid pipe and the spray pipe assembly can both be made of metal; the packing layer can be filled with regular packing or bulk packing, the regular packing can be a wire mesh corrugated packing or a plate corrugated packing, etc., the bulk packing can be in the form of an open-hole ring packing or a saddle-shaped 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, and the support rod can be fixedly connected to the inner wall of the tower.

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

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

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

[0024] To achieve the above-mentioned purpose, according to the second aspect of the present invention, a washing method is provided for washing treatment of VOCs waste gas, comprising the following steps: A. a washing liquid with an adjustable flow rate running from top to bottom is passed into a washing liquid pipe, and then sprayed out from the end of a spray pipe assembly of a rotatable pipe section arranged 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 group of spray pipe assemblies forms an annular partition coverage on the packing layer; C. the washing liquid that forms a uniform coverage on the packing fully contacts with the VOCs waste gas running from bottom to top 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 packing layer in sections, and the washing liquid sprayed by the lower spray pipe assembly covers the lower surface of the packing layer in sections, to ensure rapid and complete infiltration of the packing layer.

[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 covering impact position of the washing liquid on the packing layer.

[0027] Further, in the above technical solution, the flow rate regulation can be specifically as follows: the liquid-gas ratio of the packed scrubber is 2-3 L / Nm 3 The washing liquid flow rate is circulated every 20 minutes. Assume that the average flow rate of the washing liquid in each cycle is Q. The flow rate 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.

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

[0029] 1) The present invention provides a rotatable pipe section on the washing liquid pipe, and provides spray pipes of different lengths and evenly spaced along the tangential direction of the rotatable pipe section on the rotatable pipe section, so that the washing liquid can achieve annular coverage of different ranges of the packing layer. In this way, the packing layer can be fully covered with less washing liquid, thereby avoiding waste of water resources;

[0030] 2) The present invention arranges the spray pipe assemblies in pairs, but the upper and lower spray pipe assemblies of each pair are arranged in reverse, and the upper and lower surfaces can be evenly covered, which can ensure the rapid and complete infiltration of the packing layer, so that the washing liquid forms a liquid film on all the screens, corrugations or small holes on the surface and inside of the packing, effectively enhancing the mass transfer efficiency between the washing liquid and the exhaust gas; at the same time, the flow rate of the washing liquid can be adjusted, and the injection speed and direction of the washing liquid can be continuously changed with the rotation of the spray pipe assembly, and 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 blockage;

[0031] 3) According to the experimental research of the inventor, 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 infiltration effect of the packing layer is the best;

[0032] 4) The present invention provides an annular baffle, and the upper edge of the arc portion of the annular baffle is higher than the end of the tube of the upper spray pipe assembly, which can ensure that the washing liquid sprayed from the spray pipe can cover the area within the annular baffle, and then guide 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 the droplet short circuit caused by wall flow, which leads to a decrease in gas-liquid mass transfer efficiency;

[0033] 5) The present invention utilizes the reaction force when the washing liquid is sprayed from the spray pipe to automatically rotate the spray component, without the need for an additional motor, thus saving energy; it also has a simple structure, a small pressure drop, and low manufacturing and operating costs, and can be operated through automatic or manual adjustment of the washing liquid regulating valve, making it easy to operate.

[0034] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the first embodiment of the packed washing tower of the present invention.

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

[0037] Figure 3 It is a schematic diagram of the structure of the washing liquid pipe in the packed 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 It is a schematic structural diagram of a second embodiment of a packed washing tower of the present invention.

[0039] Description of main reference numerals:

[0040] 100-packing washing tower, 101-washing liquid inlet, 102-washing liquid outlet, 103-VOCs waste gas inlet, 104-waste gas outlet, 105-support rod;

[0041] 1-spray pipe assembly, 10-support ribs, 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-rotatable pipe section, 210-rotating blades, 211-rotatable upper pipe section, 212-rotatable lower pipe section, 22a-first bearing, 22b-second bearing, 22c-third bearing, 22d-fourth bearing, 3-packing layer, 31-packing layer support, 4-annular baffle, 41-arc-shaped portion, 42-straight edge portion, 5-demist layer. DETAILED DESCRIPTION

[0042] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0043] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0044] In this document, for the convenience of description, spatial relative terms such as "below", "below", "down", "above", "above", "upper", etc. may be used to describe the relationship between one element or feature and another element or feature in the accompanying drawings. It should be understood that the spatial relative terms are intended to include different orientations of the object in use or operation in addition to the orientation depicted in the figure. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both below and above. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatial relative terms used in this document 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 limit a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable.

[0046] Example 1

[0047] like Figures 1 to 3 As shown, the present invention provides an embodiment of a packed washing tower 100, which is used for washing and treating VOCs waste gas, and at least includes a washing liquid pipe 2 and a spray pipe assembly 1. Among them, the washing liquid pipe 2 is arranged at the axial position of the packed washing tower 100 and extends vertically, and is used to receive washing liquid from outside the tower. The bottom can be supported by a support rod 105, and the support rod 105 is fixedly connected to the inner wall of the tower. The washing liquid pipe 2 is provided with a rotatable pipe section 21 at the corresponding position of the packing layer 3. The spray pipe assembly 1 is composed of a plurality of spray pipes of different lengths and is connected to the rotatable pipe section 21. It should be noted here that the spray pipe assembly 1 can be provided with a group of spray pipes above each packing layer 3 (not shown in the figure), or a group of upper spray pipes can be provided above each packing layer 3 and a group of lower spray pipes can be provided below. The injection port of each spray pipe is arranged at the end of the pipe; the spray pipes are arranged at intervals along the circumference of the rotatable pipe section 21, and are all tangent to the rotatable pipe section 21 (reference Figure 2 When the washing liquid is sprayed out, the spray pipes of different lengths drive the rotatable pipe sections to rotate in the opposite direction through the reaction force, forming an annular partition covering of the packing layer 3 by the washing liquid (refer to Figure 2 Each group of spray pipes may be evenly spaced with more than 3 spray pipes, preferably 4-8. Figures 1 to 3 The embodiment in the embodiment uses 4 spray pipes, and the 4 spray pipes correspondingly cover the aforementioned four annular partitions.

[0048] The present invention provides a rotatable pipe section on the washing liquid pipe, and provides spray pipes of different lengths and evenly spaced along the tangential direction of the rotatable pipe section on the rotatable pipe section, so that the washing liquid can achieve annular coverage of different ranges of the packing layer. In this way, less washing liquid can be used to achieve full coverage of the packing layer, avoiding waste of water resources.

[0049] Further, preferably but not restrictively, the lengths of the spray pipes of different lengths can be set to gradually increase in a clockwise or counterclockwise direction (refer to Figure 2 ), and the number of annular partitions corresponds to the number of spray pipes. Figure 1Taking the upper and lower groups of spray pipes in the figure 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 packing layer). The longer spray pipes can be reinforced by supporting 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 packing layer).

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

[0051] Furthermore, if Figure 1 , 3 As shown, in order to realize that only the rotatable pipe section 21 in the washing liquid pipe 2 rotates, a first bearing 22a and a second bearing 22b are provided at both ends of the rotatable pipe section 21, so as to ensure that only the pipe section and the spray pipe arranged thereon rotate, while the other pipe sections are fixed. On this basis, the spray pipe assembly 1 preferably includes an upper spray pipe assembly 11 and a lower spray pipe assembly 12, wherein the upper spray pipe assembly 11 is located above the packing layer 3 and each spray pipe is inclined downward (refer to Figure 3 ), the lower spray pipe assembly is located below the packing layer 3 and each spray pipe is inclined upward. Preferably, but not restrictively, the inclination 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 packing surface, specifically 15° to 75°. Through such an arrangement, that is, the spray pipe assemblies are arranged in pairs, but the upper and lower spray pipe assemblies of each pair are arranged in reverse, and all spray pipe outlets are facing the outer surface of the packing layer (both the upper and lower surfaces can be evenly covered), which can ensure rapid and complete infiltration of the packing layer, so that the washing liquid forms a liquid film on all the wire meshes, corrugations or small holes on the surface and inside of the packing, which can effectively enhance the mass transfer efficiency between the washing liquid and the exhaust gas. The upper and lower spray pipe assemblies of the present invention have the same number of spray pipes, and the lengths and angles of the upper and lower spray pipes can correspond one to one or be slightly different, and can be set according to actual needs. For further reference Figure 1 , assuming that 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 is 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 12 is L2, preferably L1 is greater than L2, to ensure that the washing liquid in the lower spray pipe assembly 12 has an impact covering effect on the lower surface of the packing layer 3. Specifically, according to experimental research by the inventor, 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, the overall infiltration effect on the packing layer is best.

[0052] Further Figure 1 As shown, an annular baffle 4 is provided at the outer edge of the packing layer 3, and the annular baffle 4 includes an arc portion 41 and a straight edge portion 42. Among them, the arc portion 41 is on the upper edge of the packing layer 3 and extends upward toward the inner wall of the tower. The upper edge of the arc portion is higher than the end of the tube of the upper spray pipe assembly, which can ensure that the washing liquid sprayed by the spray pipe can cover the area within the annular baffle. If the arc portion 41 splashes onto the baffle, it can be diverted to the packing area. The straight edge portion 42 extends downward from the lower edge of the arc 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. Through such a design, the influence of wall flow can be effectively reduced, and the droplet short circuit caused by wall flow can be avoided, which leads to a decrease in gas-liquid mass transfer efficiency.

[0053] It should be noted that the packing washing tower 100 can be provided with multiple packing layers 3, and corresponding positions of each packing layer 3 can be provided with Figures 1 to 3 Specifically, the washing liquid pipe 2 is provided with one or n pairs of bearings, which divide 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, namely, the washing liquid inlet section, the rotatable pipe section 21 and the washing liquid outlet section (i.e. Figures 1 to 3 ); when there are n pairs (n is greater than or equal to 2) of bearings, the washing liquid pipe 2 is divided from top to bottom into a washing liquid inlet section, the first to n rotatable pipe sections, and a washing liquid outlet section. The number of pairs of spray pipe assemblies is the same as the number of bearing pairs and the number of packing layers. With such an embodiment, the spray pipe assemblies above and below each layer of packing can spray washing liquid onto the packing layer 3 at the same time, which can ensure that the packing layer 3 is quickly and completely infiltrated, so that the washing liquid quickly forms a liquid film on the surface and inside of the packing, thereby enhancing the mass transfer efficiency between the washing liquid and the gas; at the same time, the flow rate of the washing liquid can be adjusted (see Figure 1 The flow regulating valve 20 in the spray pipe assembly can change the spray speed of the washing liquid continuously with the rotation of the spray pipe assembly, and the impact position on the packing layer also changes continuously, which is more conducive to the discharge of dirt in the packing layer and avoids blockage.

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

[0055] Furthermore, a demisting layer 5 is provided above the uppermost packing layer 3 of the present invention (i.e., at 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 is subjected to gas-liquid mass transfer and washing in the packing layer, and is demisted by the demisting layer 5 before being discharged from the exhaust gas outlet 104.

[0056] Example 2

[0057] like Figure 4 As shown, the present invention provides another embodiment of a packing washing tower. The difference between this embodiment 2 and embodiment 1 is that the rotatable pipe section is further provided with a third bearing 22c and a fourth bearing 22d, and the third bearing 22c and the first bearing 22a, the fourth bearing 22d and the second bearing 22b respectively further divide the rotatable pipe section into two relatively independent sections (the two sections can rotate separately), wherein the upper section (i.e., the rotatable upper pipe section 211) is used to set the upper spray pipe assembly, and the lower section (i.e., the rotatable lower pipe section 212) is used to set the lower spray pipe assembly. Further, preferably but not restrictively, a rotating blade 210 is provided below the lower spray pipe assembly of the lower section, and under the driving action of the VOCs exhaust gas running from bottom to top, the rotating blade assists in driving the lower spray pipe assembly to rotate, so that the rotation speed of the lower spray pipe assembly can be higher than that of the upper spray pipe assembly, so that the lower spray pipe assembly can have a stronger impact coverage on the lower surface of the packing layer, and the infiltration speed of the washing liquid on the packing can be further improved.

[0058] When the packing layer is multi-layer (ie n layers), the washing liquid pipe is provided with 2n pairs of bearings, the number of bearing pairs is twice the number of spray pipe assemblies, and the number of spray pipe assemblies is the same as the number of packing layers, which will not be repeated here.

[0059] Example 3

[0060] The present invention provides a washing method using the washing tower of Example 1 or Example 2. The method is used for washing VOCs waste gas, and comprises the following steps:

[0061] Step S101, the washing liquid running from top to bottom with adjustable flow rate 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 arranged on the washing liquid pipe 2. Specifically, in this embodiment, the washing liquid inlet 101 is arranged at the top of the tower, and the washing liquid outlet 102 is arranged at the bottom of the tower, so that the washing liquid runs from top to bottom, and the flow rate and flow velocity are adjusted by the flow regulating valve 20;

[0062] Step S102, the reaction force of the sprayed washing liquid on the spray pipe drives the spray pipe assembly 1 to rotate, and the washing liquid sprayed from the spray pipes of different lengths in each group of spray pipe assemblies 1 forms an annular partitioned coverage on the packing layer 3; preferably, but not restrictively, the washing liquid sprayed by the upper spray pipe assembly 11 can cover the upper surface of the packing layer 3 in a partitioned manner, and the washing liquid sprayed by the lower spray pipe assembly 12 can cover the lower surface of the packing layer 3 in a partitioned manner, so as to ensure the rapid and complete infiltration of the packing layer. During the rapid infiltration process, the annular baffle between the packing layer 3 and the tower body can effectively reduce the influence of the 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 coverage impact position of the washing liquid on the packing layer. Specifically, the liquid-to-gas ratio of the packed washing tower is 2 to 3L / Nm 3The washing liquid flow rate is circulated once every 20 minutes. Assuming that the average flow rate of the washing liquid in each cycle is Q, the flow rate 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. In this way, the flow direction and flow rate of the washing liquid change continuously with the rotation of the spray component, and the impact position on the packing layer also changes continuously, which is conducive to the discharge of dirt in the packing layer and is not easy to be blocked;

[0063] Step S103, the washing liquid that evenly covers the packing is fully contacted with the VOCs waste gas running from bottom to top in the packing layer and completes 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 body and runs upward. When passing through the packing layer, it contacts with the infiltrated droplets for gas-liquid mass transfer. When the packing layer is multi-layer, the final washing is completed by step-by-step contact. The washed 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 effects as embodiments 1 and 2, which will not be described in detail here.

[0065] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. Any simple modifications, equivalent changes and modifications made to the above exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A packed washing tower, characterized in that: Used for scrubbing of VOCs waste gas, including: A washing liquid pipe is arranged at the axial center of the washing tower and extends vertically, and is used to receive washing liquid from outside the tower; a rotatable pipe section is provided on the washing liquid pipe at a corresponding position of the packing layer; The spray pipe assembly is composed of a plurality of spray pipes of different lengths and connected to the rotatable pipe section, the spray port of each spray pipe is arranged at the end of the pipe; the spray pipes are arranged at intervals along the circumference of the rotatable pipe section and are tangent to the rotatable pipe section; when the spray pipes of different lengths spray cleaning liquid, the rotatable pipe section is driven to rotate by the reaction force, thereby forming an annular partitioned coverage of the packing layer by the cleaning liquid.

2. The packed washing tower according to claim 1, characterized in that: The lengths of the spray pipes of different lengths gradually increase in a clockwise or counterclockwise direction, and the number of the annular partitions corresponds to the number of the spray pipes.

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

4. The packed washing tower according to claim 1, characterized in that: The rotatable pipe section has a first bearing and a second bearing at both ends.

5. The packed washing tower according to claim 4, characterized in that: The spray pipe assembly comprises an upper spray pipe assembly and a lower spray pipe assembly. The upper spray pipe assembly is located above the packing layer and each spray pipe is inclined downward, and the lower spray pipe assembly is located below the packing layer and each spray pipe is inclined upward.

6. The packed washing tower according to claim 5, 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 end of the pipe and the filler surface, specifically 15° to 75°.

7. The packed washing tower according to claim 6, characterized in that: The distance between the upper surface of the packing layer and the end of the spray pipe in the upper spray pipe assembly is 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 L2, and L1 is greater than L2.

8. The packed washing tower according to claim 7, characterized in that: The L1 is 0.1 to 0.4 times the radius R of the tower body, and the L2 is 0.05 to 0.2 times the radius R of the tower body.

9. The packed washing tower according to claim 1, characterized in that: The outer edge of the packing layer is provided with an annular baffle, and the annular baffle comprises: An arc-shaped portion, which is arranged at the upper edge of the packing layer and extends upward toward the inner wall of the tower, and the upper edge of the arc-shaped portion is higher than the pipe end of the upper spray pipe assembly; A straight edge portion extends downward from the lower edge of the arc-shaped portion toward the inner wall of the tower, and an angle between the straight edge and the upper edge of the packing layer is greater than 90 degrees.

10. The packed washing tower according to claim 5, characterized in that: The rotatable pipe section is also provided with a third bearing and a fourth bearing, and the third bearing and the first bearing, the fourth bearing and the second bearing respectively further divide the rotatable pipe section into two relatively independent sections, wherein the upper section is used to set the upper spray pipe assembly, and the lower section is used to set the lower spray pipe assembly.

11. The packed washing tower according to claim 10, characterized in that: A rotating blade is provided below the lower spray pipe assembly of the lower section. Driven by the VOCs exhaust gas running from bottom to top, the rotating blade assists 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.

12. The packed washing tower according to claim 1, characterized in that: The washing liquid pipe and the spray pipe assembly are both 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 hole annular packing or saddle packing, and the packing material is metal or ceramic.

13. The packed washing tower according to claim 1, characterized in that: The bottom of the washing liquid pipe is supported by a support rod, and the support rod is fixedly connected to the inner wall of the tower.

14. The packed washing tower according to claim 1, characterized in that: A regulating valve for regulating the flow in the washing liquid pipe is arranged at the top of the packed washing tower.

15. The packed washing tower according to claim 1, characterized in that: The packed washing tower is provided with a demisting layer, which is located above the packed layer and at the fixed pipe section of the washing liquid pipe.

16. The packed scrubbing tower according to any one of claims 1 to 15, characterized in that: The spray pipe assembly is provided at the corresponding position of each packing layer.

17. A washing method, characterized in that: Used for the scrubbing treatment of VOCs waste gas, including the following steps: A. The washing liquid with adjustable flow rate running from top to bottom is introduced into the washing liquid pipe, and then sprayed out 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 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 group of spray pipe assemblies forms an annular partition covering on the packing layer; C. The washing liquid that evenly covers the filler is fully in contact with the VOCs waste gas running from bottom to top in the filler layer to complete the gas-liquid mass transfer.

18. The washing method according to claim 17, characterized in that: The step B further includes: the washing liquid sprayed by the upper spray pipe assembly covers the upper surface of the packing layer in sections, and the washing liquid sprayed by the lower spray pipe assembly covers the lower surface of the packing layer in sections, so as to ensure rapid and complete infiltration of the packing layer.

19. The washing method according to claim 17, characterized in that: The rotation speed of the spray pipe assembly is changed by adjusting the flow rate of the washing liquid, thereby adjusting the covering impact position of the washing liquid on the packing layer.

20. The washing method according to claim 19, characterized in that The flow rate adjustment is specifically: the liquid-gas ratio of the packed scrubber is 2-3 L / Nm 3 The washing liquid flow rate is circulated every 20 minutes. Assume that the average flow rate of the washing liquid in each cycle is Q. The flow rate 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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