JP2011078928A - Exhaust gas treatment apparatus and method for concentrating volatile organic compound and the like - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas treatment apparatus which can efficiently reduce the amount of volatile organic compounds (VOC) contained in exhaust gas 51 discharged from a painting booth 5 and the like. <P>SOLUTION: The exhaust gas treatment apparatus 10 includes a collection water storage chamber 1, a gas-liquid mixer 21 and a horizontal gas-liquid cyclone 22 disposed on the collection water storage chamber 1, and a vertical vaporizing cylinder 3 with an air diffuser 35. The gas-liquid mixer 21 includes a plural stages of plate-like porous bodies (air filters for coarse dust) 211-1 to 211-4, and a plurality of nozzles 212 for supplying water 56 to the whole surface of a highest-stage plate-like porous body 211-1, and partially collects the VOC by bringing the exhaust gas 51 into contact with the water 56. Collection water 56A discharged from the gas-liquid cyclone 22 is sent to the top of the vaporizing cylinder 3 through the collection water storage chamber 1. The VOC in the collection water is dissolved in air 52 sent from the air diffuser 35 in the form of bubbles to generate concentrated exhaust gas 53. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is a facility for painting, bonding, printing, rubberizing, reaction and washing with a solvent, application of a release agent, or the like, or a storage location for a solvent, a drying / curing location for a product, etc. The present invention relates to an exhaust treatment apparatus and method for concentrating and treating volatile organic compounds and suspended particulate matter from exhaust gas discharged more. In particular, the amount of emissions of volatile organic compounds and suspended particulate matter is reduced by concentrating volatile organic compounds and removing suspended particulate matter with simple equipment with low equipment and operating costs. In connection with this, the present invention relates to an apparatus and a method capable of greatly reducing the equipment cost or the processing cost.

  In recent years, air pollution and health effects caused by volatile organic compounds (VOC) have become a problem worldwide, and emission regulations have been tightened and reduction targets have been set. Volatile organic compounds (VOC) are the main cause of photochemical smog due to the formation of photochemical oxidants, and are also said to produce suspended particulate matter (SPM). In Japan, emission regulations based on the revised Air Pollution Control Law have been implemented with the goal of reducing emissions by 30% from the 2000 level until 2010. For this reason, offices that handle organic solvents, such as automobiles and other painting plants, are required to clear emission regulations that are becoming stricter year by year.

  In order to reduce VOC emissions, it is necessary to reduce the amount of organic solvents used, or to remove VOCs even partially from exhausted exhaust from organic solvents. is there. Methods for removing or reducing VOC in exhaust gas can be broadly classified into combustion treatment methods and adsorption / absorption treatment methods. The combustion treatment method includes a method of directly using a burner flame and a method of using a heat storage body such as ceramic or a catalyst at a combustion location in order to increase combustion efficiency. Further, the adsorption / absorption treatment method includes a method of adsorbing on activated carbon and the like, a method of absorbing VOC such as toluene, xylene, ethylbenzene in oil or a non-hydrophilic high boiling point solvent. If the entire amount of exhaust gas is processed by the combustion processing method, it is possible to bring the VOC emissions closer to zero. However, in addition to excessive fuel costs, there are problems of pollutants discharged by fuel combustion and problems of increased carbon dioxide emissions. Even in the adsorption / absorption treatment method, there is a cost for regeneration of activated carbon or the like and replacement for a certain period of time, and in many cases, the cost cannot be reduced compared with the combustion treatment method.

  Therefore, Patent Document 1 proposes that an activated carbon disk is disposed in the exhaust passage to adsorb VOC, and that VOC is desorbed by passing hot air into a part of the angular area (fan-shaped area) of the activated carbon disk to perform catalytic combustion. Has been. By sequentially rotating the activated carbon disk, desorption is performed for each fan-shaped region when a certain amount of adsorption is performed. That is, it is proposed that VOC is concentrated using activated carbon and then burned using a catalyst.

  On the other hand, Patent Document 2 describes that an adsorption liquid containing a liquid polymer substance is used to remove VOCs such as toluene by the liquid polymer substance from the exhaust from the coating booth using the adsorption liquid. Yes. The exhaust gas purified by the adsorbing liquid is further purified by a dry filter, and the liquid polymer substance and the like are removed from the adsorbing liquid by centrifugation or the like.

  Moreover, in patent document 3, in order to process the volatile organic compound (VOC) contained in groundwater etc., while to-be-processed water is injected in a spherical cyclone, ozone is blown and an eddy current is made and it contacts with ozone. To be disassembled.

  On the other hand, suspended particulate matter (SPM) having a particle size of 10 μm or less is also a problem because it can cause respiratory diseases and allergic diseases, and needs to be removed from the exhaust. To capture and treat suspended particulate matter (SPM), various combustion treatment methods and adsorption / absorption treatment methods can be used in the same manner as described above, and to some extent, they are removed at the same time as volatile organic compounds (VOC). It is possible. However, when a large amount of suspended particulate matter (SPM) is generated, or when the suspended particulate matter (SPM) particle size is 0.1μm or less, the suspended particulate matter (SPM) is efficiently removed. Was generally difficult.

  Therefore, the inventors of the present invention in Patent Document 4 contacted exhaust gas and vegetable oil in an overflow type triple contactor, and then attached suspended particulate matter (SPM) by a horizontal cyclone device. It was proposed to separate the vegetable oils that were made. This vegetable oil is mixed with the engine fuel and burned completely in the engine, whereby the suspended particulate matter (SPM) is also burned.

JP 2002-331223 A JP2007-237101A JP2004-344866 JP 2006-102618 A

  When a volatile organic compound (VOC) is concentrated and treated as in Patent Document 1, a relatively large amount of activated carbon is required, and heating for sending hot air is required, which is an operating cost for concentration. And the equipment cost cannot be made very small. Also, it is not suitable for removing suspended particulate matter (SPM) at the same time.

  Further, as in Patent Document 2, when a volatile organic compound (VOC) is adsorbed and removed by a liquid polymer substance, the adsorbed liquid polymer substance must always be discharged by centrifugation or the like. Always add new liquid polymer material. Therefore, the equipment cost and the operation cost cannot always be reduced.

  When decomposing a volatile organic compound (VOC) using ozone as in Patent Document 3, an expensive ozone generator is required, and a mechanism for treating ozone remaining after use is necessary. Therefore, it is not suitable for treating exhaust gas having a low concentration of volatile organic compounds (VOC), resulting in high costs. Furthermore, the treatment of suspended particulate matter (SPM) must be performed separately.

  On the other hand, the suspended particulate matter (SPM) removal device proposed in Patent Document 4 can efficiently remove suspended particulate matter (SPM) but cannot concentrate volatile organic compounds (VOC). .

  The inventors of the present invention have made extensive studies in view of the above-mentioned problems. By simply bringing water into contact with exhaust gas, the volatile organic compound (VOC) is “collected” with water in some form, and from this water. The idea was that volatile organic compounds (VOC) could be separated. Common sense is that petroleum-based solvents such as toluene and cyclohexane do not dissolve in water, and water-soluble solvents such as methanol are difficult to separate from water. Therefore, the idea of the inventors was considered insane at first.

  However, during further diligent investigations, I learned that it is possible to concretely realize a seemingly insane idea using only a simple and inexpensive device mechanism.

  As described above, the present invention is intended to achieve the concentration of volatile organic compounds with a simple apparatus having a low equipment cost and an operating cost.

  In the exhaust treatment apparatus of the present invention, the exhaust gas (51) containing the volatile organic compound (VOC) is brought into contact with the water (56), whereby the volatile organic compound (VOC) is at least partially captured by the water (56). Gas-liquid mixer (21) to collect, gas-liquid separator (22) disposed downstream of the gas-liquid mixer (21), and collected water (56A) discharged from the gas-liquid separator (22) And a vaporization separation device (1,3) that vaporizes and separates volatile organic compounds (VOC) retained in the collected water (56A) from the water. . The vapor separation device (1,3) is preferably configured such that the collected water (VOC retention water) (56A) discharged from the gas-liquid separator (22) is a smaller amount of air than the exhaust (51), and / or A concentrated exhaust generation system that contacts a part (51B) of the exhaust (51) to generate a concentrated exhaust (53,51C) having a higher concentration of volatile organic compounds (VOC) than the original exhaust (51). is there. Preferably, the water in the collection / separation device (1, 3) is returned to the gas-liquid mixer (21) at least partially for reuse as water for collection (56). System (48, 48A, 46, 46A) is provided.

  By separating the exhaust gas containing the volatile organic compound (VOC) after contacting it with water, the concentration of the volatile organic compound (VOC) in the exhaust gas can be reduced. In particular, the concentration of volatile organic compounds (VOC) is high by bringing the water (collected water) after contact with the exhaust into contact with a relatively small amount of air or by heating. Concentrated exhaust or concentrated steam can be obtained. Therefore, the amount of volatile organic compound (VOC) emissions can be reduced by treating only concentrated exhaust gas or concentrated steam by combustion or the like.

1 is a vertical sectional view showing an overall configuration of an exhaust treatment apparatus according to a first embodiment. It is a typical perspective view which shows the external appearance of the bench scale prototype example about the exhaust-gas treatment apparatus of FIG. It is a typical disassembled perspective view about the gas-liquid mixing promotion member of each step | level in the gas-liquid mixer shown in FIG. FIG. 4 is a schematic vertical sectional view for further explaining the gas-liquid mixer shown in FIGS. 1 and 3. It is a partially broken perspective view which shows the gas-liquid separation cyclone in FIG. FIG. 6 is a vertical sectional view along the axial direction of the gas-liquid separation cyclone in FIG. 5. It is the vertical sectional view which looked at the section which meets the CC line of Drawing 5 from the downstream. It is the vertical sectional view which looked at the cross section in alignment with the DD line | wire of FIG. 5 from the downstream. FIG. 3 is a vertical sectional view similar to FIG. 1 showing an exhaust treatment apparatus of a second embodiment.

  The exhaust treatment apparatus 10 of the present invention is configured to contact and mix exhaust gas containing a volatile organic compound (VOC) with water and to separate the volatile organic compound (VOC) in the exhaust gas by separating it from the contacted and mixed water. ) VOC collector (exhaust gas purification system) 2 and VOC vaporizer that separates volatile organic compounds (VOC) from the collected water (VOC retention water) discharged from this VOC collector It consists of. In a preferred embodiment, the VOC vaporization / separation device comprises contacting the collected water discharged from the VOC collection device (VOC retention water) with a part of the exhaust or a smaller amount of air than the exhaust, thereby causing a volatile organic compound. Concentrated exhaust generation systems 1 and 3 that generate concentrated exhaust with a high concentration of (VOC) and discharge from the exhaust port. The VOC vaporization separation apparatus is not limited to such a concentrated exhaust generation system. For example, in a state in which collected water (VOC retention water) is stored, heating, decompression, and vigorous stirring such as ultrasonic waves are applied to It may be one that produces a concentrated vapor containing a volatile organic compound (VOC) at a high concentration.

  Further, in a preferred embodiment, the water in the vaporization separator is collected at least partially back to the gas-liquid mixer (21) to be reused as water for collection (56) (48, 48A, 46, 46A).

  In a preferred embodiment, the VOC collection device 2 includes a gas-liquid mixer 21 and a horizontal gas-liquid separation cyclone 22 connected downstream thereof.

  In a preferred embodiment, the gas-liquid mixer 21 includes a plate-like porous body 211 made of a plate-like fiber aggregate or foam capable of capturing most of particles having a particle diameter of 10 μm or more, and water 56 on the entire surface. It consists of a nozzle 212 for supplying or other water supply means (for example, many stainless thin tubes). As the plate-like porous body 211, for example, a commercially available product as an air filter for dust removal installed at an outside air inlet of a ventilator or a vent of an air conditioner can be used as it is. From the standpoint of reducing pressure loss and achieving efficient gas-liquid contact, fiber assemblies are preferred, especially those in which the three-dimensional network structure (intersections and nodes) is fixed by fusion or the like as a nonwoven fabric. preferable. For example, a nonwoven fabric manufactured by a spunbond method using a thermoplastic synthetic resin such as thermoplastic polyester or polyolefin can be used. However, inorganic fibers such as glass fibers and metal fibers such as stainless steel wires can also be used. The fiber assembly may be one in which meshes forming a sieve surface overlap, or may be a knitted fabric or the like. Further, as the plate-like porous body 211, a honeycomb structure or open cell resin foam can be used in some cases. The thickness of the plate-like porous body 211 is, for example, 5 to 40 mm, particularly 10 to 30 mm.

  In a preferred embodiment, the gas-liquid mixer 21 is a high-density gas-liquid mixer configured as follows. That is, a plurality of stages of plate-like porous bodies 211-1 to 211-4 for gas-liquid mixing are arranged in the passage of the exhaust gas 51 in the gas-liquid mixer 21, and each plate-like porous body 211 has a thickness of 0.5 mm. It is supported by a punching sheet 213 having holes with the above diameters uniformly formed (see FIGS. 1 and 4). In particular, the punching sheet 213 is obtained by forming a circular hole 213A having a diameter of 0.5 to 8 mm, for example, in a metal plate such as a stainless steel plate or a galvanized steel plate having a thickness of 0.2 to 1.0 mm. The aperture ratio of the punching sheet 213 is 20 to 50%, for example. For example, a gap of 2 to 15 mm is provided between the punching sheet 213 that supports one plate-like porous body 211-1 and the plate-like porous body 211-2 at the next stage. Due to the presence of the punching sheet 213 having an appropriate aperture ratio, not only the plate-like porous body 211 is supported and fixed, but also the water 56 for VOC collection is pressed against the punching sheet 213 by the flow of exhaust 51 and gravity. After staying temporarily, it is ejected into the gap through the hole 213A. Due to the action of the punching sheet 213, there is sufficient water for gas-liquid mixing at any location over the entire surface of each plate-like porous body 211. Further, it is considered that the speed at which the exhaust 51 and water pass through the plate-like porous body 211 is prevented from varying in the plane of the plate-like porous body 211, and efficient VOC collection is performed. It is assumed that a kind of spraying action is performed toward the upstream surface of the next-stage plate-like porous body 211 at the time of ejection from the hole 213A.

  The gas-liquid mixer 21 is preferably a vertical type. That is, the exhaust 51 containing volatile organic compounds (VOC) is introduced from the upper part of the gas-liquid mixer 21, and passes through the plate-like porous body 211 of each stage arranged substantially horizontally for VOC collection. While coming into contact with the water 56, it is discharged from below in the mist state in which the gas and liquid are mixed in this way. The supply amount of water 56 for collection to the gas-liquid mixer 21 (volume basis, L / min) should be set to 1/1500 to 1/100 of the amount of exhaust 51 (volume basis, L / min). For example, by setting to 1/1000 to 1/200, particularly 1/700 to 1/300, volatile organic compounds (VOC) can be collected. Usually, even if the amount of water is larger than this range, the effect is not so much seen.

  In a preferred embodiment, the gas-liquid separation cyclone 22 includes a rotational force applying chamber 22B for applying a rotational force along a horizontal central axis, and a separation chamber 22C connected downstream thereof. The diameters of the cylinders 227 and 228 forming the peripheral wall of the separation chamber 22C are slightly smaller than the diameter of the outer cylinder 221 forming the peripheral wall of the rotational force applying chamber 22B. The rotational force applying chamber 22B includes a pair of guide plates 224 having the same shape and dimensions extending in a spiral shape when viewed from a cross section perpendicular to the central axis, and a space 22B1 between the guide plates 224 in the rotational force applying chamber 22B. And a shielding plate 226 that shields from the upstream space 22B2. The mist flow introduced from the gap between the contour of the shielding plate 226 and the outer cylinder 221 is guided to the space 22B1 between the guide plates 224 while proceeding to the downstream side, and is radial along the guide plates 224. It is sent inward and a rotational force is applied. A small-diameter cylindrical portion protrudes from the wall surfaces of the upstream and downstream end portions into the separation chamber 22C. In addition, the cylinders 227 and 228 forming the peripheral wall of the separation chamber 22C are provided with an opening 241 at the lower end, thereby forming a C-shape that opens downward in a cross section perpendicular to the central axis. The purified exhaust gas 51A is discharged through the downstream cylindrical portion 243, and the collected water 56A is discharged through the downward opening 241 and received in the lower liquid receiving tank 242.

  In a preferred embodiment, a kind of demister 23 for removing water droplets remaining in the purified exhaust gas 51A is connected downstream of the gas-liquid separation cyclone 22. The demister 23 includes a collision demister 23A connected to the discharge port of the gas-liquid separation cyclone 22. The collision type demister 23A includes a wall surface 23B against which the exhaust gas 51A discharged in the horizontal direction from the outlet is abutted, and a plate-like porous body 231 for airflow collision arranged along the wall surface 23B. The mist captured by the plate-like porous body 231 for air current collision flows down through the plate-like porous body 231 and is sent to the concentrated exhaust generation systems 1 and 3 through a small-diameter pipe (not shown). In particular, it is sent into the collected water storage chamber 1 or the vaporization chamber 3. As the plate-like porous body 231 for the air current collision of the demister 23, the same thing as the plate-like porous body 211 of the gas-liquid mixer 21 can be mentioned as a preferable one.

  The demister 23 is further provided with a passing demister section 23C as necessary. The passing demister 23C is connected to the upper opening of the collision demister 23A or is provided integrally therewith, and removes residual mist when the exhaust 51A passes through and is discharged. The passage type demister 23C is provided with a plate-like porous body 232 for airflow passage so as to block the flow of the exhaust 51A upward. As the plate-like porous body 232 for airflow passage, the same plate-like porous body 211 of the gas-liquid mixer 21 or a coarser one can be used.

  In a preferred embodiment, the VOC vaporization separation devices 1 and 3 are the collected water storage chamber 1 for storing the collected water 56A, the vaporization chamber 3 including the water tank 31 and the diffuser 35, and the collection of the collected water storage chamber 1. It consists of a collected water supply pipe 47 and a pump 47A that send the water 56A to the upper part of the water tank 31 of the vaporization chamber 3. The diffuser 35 sends volatile organic compounds dispersed or dissolved in the collected water 56A by sending a part of the outside air or exhaust gas as bubbles at the bottom of the water tank 31 of the vaporization chamber 3 ( VOC) is expelled to the concentrated exhaust chamber 32 that forms the upper part of the vaporization chamber 3. Any air diffuser 35 can be used as long as air bubbles that are fine to some extent can be generated over substantially the entire bottom of the water tank 31. For example, various diffuser plates, diffuser tubes, diffusers and the like used in biological reaction tanks such as water treatment and food industry can be used. In general, it is preferable to use a diffuser plate extending substantially over the entire bottom surface in order to uniformly generate bubbles on the entire surface. In addition, the hole diameter of the air diffusion hole can be appropriately selected within a range of 100 μm to 2 mm, and may be made of a resin film, ceramic, or the like. For example, a diffuser plate having a pore diameter of 150 to 400 μm can be mentioned as a preferable one.

  On the other hand, the amount of blowing from the air diffuser 35 can be 0.2 to 2%, particularly 0.3 to 1% of the total amount of exhaust gas 51 to be processed. In addition, when a part of the exhaust gas is sent to the VOC vaporization separators 1 and 3 together with the collected water 56A, the amount of the exhaust gas is 5 to 40%, particularly 10 to 25%, of the blowing amount of the diffuser 35 Can be suppressed.

  In order to promote vaporization of the volatile organic compound (VOC), water in the water tank 31 of the vaporization chamber 3 can be appropriately heated. For example, vaporization can be greatly promoted by raising the water temperature of the water tank 31 to 35 ° C. or higher, particularly 35 to 40 ° C. Heating is preferably performed in the vicinity of the bottom surface below the diffuser holes such as a diffuser plate. The heating means is preferably a panel heater that can maintain a uniform surface temperature over a wide area.

  As the panel heater, heated oil, hot water, etc. may circulate around the piping in the panel, and the smoke from the small combustion cylinder 6 for burning the concentrated exhaust 53, 51C is contained in the panel. It is possible to go around the piping. Moreover, it is not limited to a panel-like one, and a heating medium such as warm water may be provided around the bottom surface. For heating the heating medium here, the exhaust heat from the small combustion cylinder 6 can be used, and the exhaust heat and hot waste water from various facilities in the factory can be used as appropriate. For example, it is possible to use hot waste water that comes out when a mold for heat molding is cooled with water. In some cases, a heat pump or electric heat can also be used.

  Water is sent to the gas-liquid mixer 21 (that is, at least one) from the bottom of the water tank 31 of the vaporization chamber 3, particularly from the lower side of the air diffuser 35, directly or via an appropriate storage location. . Further, the concentrated exhaust 53 in the concentrated exhaust chamber 32 is sent to the processing system for processing. The water supplied to the upper part of the water tank 31 continues to be subjected to the action of rising bubbles as it descends to the bottom of the water tank 31 of the vaporization chamber 3 by convection. Therefore, the water 58 at the bottom of the water tank 31 of the vaporization chamber 3 has a low concentration of volatile organic compounds (VOC) and is circulated to the gas-liquid mixer 21 to collect volatile organic compounds (VOC). Suitable for If the water in the water tank 11 of the collected water storage chamber 1 is substantially stationary, the lower part of the water tank 11 of the collected water storage chamber 1 can be used as the storage location of the water 58.

  Since the concentrated exhaust 53 can be at least 1/10, particularly 1/30 to 1/150, of the amount of the exhaust 51 discharged from the painting booth 5 or the like, the processing cost can be greatly reduced. In the case of simple combustion processing, fuel and other energy costs and device costs are substantially proportional to the amount of gas to be processed, so that the processing costs can be greatly reduced compared to the case where the entire exhaust 51 is subjected to combustion processing.

  The VOC vaporization separators 1 and 3 can be provided with a mechanism for filtering and removing suspended particulate matter (SPM). If the gas-liquid mixer 21 as described above is used, for example, 99.7% or more of suspended particulate matter (SPM) of 0.74 μm or more can be removed (Big Bang Co., Ltd. website http: // www .eco-bigbang.co.jp / a1b). When the exhaust gas 51 flowing into the gas-liquid mixer 21 contains a large amount of suspended particulate matter (SPM), the aggregate of suspended particulate matter (SPM) in the collected water 56A is removed by filtration, Alternatively, the concentrated exhaust can be generated by contacting the collected water with air while removing.

  In a preferred embodiment, the collected water storage chamber 1 is provided with a powder removal filter 13 that receives water overflowing from the water tank 11 and separates aggregates of suspended particulate matter (SPM) therefrom, A storage tank 14 for storing the filtered water that has passed through the body removal filter 13 and / or a discharge pipe for discharging the filtered water are provided. In addition, the bottom of the water tank 11 can be equipped with an air diffuser 15 similar to that which can be installed at the bottom of the vaporization chamber 3 in order to facilitate the separation of the aggregates and floating near the water surface as appropriate. . However, the amount of air fed from the air diffuser 15 may be sufficient to promote the separation of the suspended particulate matter (SPM). For example, the amount of air fed by the air diffuser 35 in the vaporizing chamber 3 is 10 to 20%. can do.

  In a preferred embodiment, a heating device 17 such as a panel heater similar to that which can be installed at the bottom of the vaporization chamber 3 can be further provided at the bottom of the water tank 11 of the collected water storage chamber 1. For example, if it is heated to 30 to 40 ° C., it is easier to maintain the water temperature in the water tank 31 at 35 to 40 ° C. when it is fed into the vaporizing chamber 3, which is advantageous in promoting vaporization. is there. In addition, when the aeration device 15 is provided together with the heating device in the water tank 11 of the collected water storage chamber 1, the vaporization of volatile organic compounds (VOC) in the collected water storage chamber 1 is considerably increased. Can go up.

  Note that the volatile organic compound (VOC) is obtained by removing methane and most of the fluorine-containing compounds from those which are gases at the time of discharge, as defined by the Air Pollution Control Law. Typical examples with large emissions are toluene, xylene, benzeneethylbenzene, ethyl acetate, decane, methanol, dichloromethane, various ketones, and isobutane. That is, some are freely soluble or miscible in water, some are miscible, and some are immiscible. Even if it is almost immiscible with water, it will be dispersed in water in the gas-liquid mixer, and a substantial part will remain retained in the water during the separation in the gas-liquid separator. On the other hand, suspended particulate matter (SPM) contains all particulate matter with a diameter of 10 μm or less that floats in the exhaust, including solid dust and dust, as well as liquids such as mist and aerosol. It is. Suspended matter having a diameter of 10 μm or more can be removed relatively easily by an air filter or the like.

  Below, the exhaust-air-treatment apparatus 10 of 1st Embodiment is demonstrated using FIGS. The exhaust treatment apparatus 10 of the first embodiment is a bench scale prototype as shown in the external view of FIG. 2, and was used for acquiring test data to be described later. However, it differs from the prototype device used when acquiring test data only in that the gas-liquid mixer 21 is a vertical type. Note that the control panel 7 appears in the actual prototype shown in FIG. 2, but is omitted in FIG.

  FIG. 1 is a schematic vertical sectional view showing the overall configuration of the exhaust treatment apparatus 10. As shown in FIG. 1, the exhaust treatment apparatus 10 of the embodiment includes a collected water storage chamber 1, a VOC collection device 2, a vaporization chamber 3, and a piping / pump system. The VOC collection device 2 includes a gas-liquid mixer 21 that makes the exhaust gas 51 discharged from the painting booth 5 contact the water 56, and a horizontal type that is disposed downstream of this to separate the collected water 56A from the purified exhaust gas 51A. The gas-liquid separation cyclone 22 and a demister 23 that removes a little remaining mist of the collected water 56A from the exhaust 51A. Below the gas-liquid separation cyclone 22, a funnel-shaped or hopper-shaped collected water receiving portion 24 for receiving the collected water 56A is provided.

In the prototype of the specific example shown in the figure, thinner was sprayed into a box as a small painting booth 5 using a spray gun. Then, the exhaust 51 was sent into the upper part of the gas-liquid mixer 21 at an air volume of 4.5 m ³ / min (4500 L / min) by the exhaust duct 41 and a blower 41A installed in the middle of the exhaust duct 41. The discharge end of the exhaust duct 41 is connected to the upper opening of the gas-liquid mixer 21 through the connection duct portion 41B.

  First, the collected water storage chamber 1 and the vaporization chamber 3 shown in FIG. 1 will be described.

  The collected water storage chamber 1 is inside a container 1A having a rectangular vertical cross section, and includes a water tank 11 that occupies most of the container, and an exhaust chamber 12 above the water tank 11. A collected water receiving portion 24 is connected to the ceiling wall 1D of the collected water storage chamber 1 through a vertical cylinder 24A. The collected water 56A flows down this inner wall surface and passes through the exhaust chamber 12. Fall into the aquarium 11. A part of the exhaust 51A is fed into the exhaust chamber 12 through the vertical cylinder 24A. This is because the inside of the gas-liquid separation cyclone 22 has a slightly higher pressure than the inside of the collected water receiving portion 24 so that the collected water 56A can be separated smoothly. As shown in FIG. 1, a discharge duct (second concentrated exhaust duct) 42 is connected near the upper end of the collected water storage chamber 1. The exhaust 51A sent to the exhaust chamber 12 partially contacts the collected water 56A at the water surface of the water tank 11 and so on, and partially dissolves volatile organic compounds (VOC). In this way, the exhaust gas 51C having a high concentration of volatile organic compounds (VOC) is discharged. In the illustrated example, an adjustment valve 42A is provided in the middle of the second concentrated exhaust duct 42, and an appropriate amount of exhaust gas is discharged from the gas-liquid separation cyclone 22 by using this to adjust the pressure in the exhaust chamber 12. Can flow in.

  In the illustrated example, a punching sheet 12A is horizontally disposed as a “buffer plate” at a position slightly higher than the water surface of the water tank 11. This punching sheet 12A relaxes the water flow of the collected water 56A falling from the ceiling wall over a wide area, so that it hits the water surface of the aquarium 11, and gently flows into the upper part of the aquarium 11. It is what you want to do. As the punching sheet 12A, the same punching sheet 213 used in the gas-liquid mixer 21 can be used. In the example shown in the figure, the punching sheet 12A is considerably smaller than the water surface of the water tank 11, but it may be spread over the entire water surface of the water tank 11. In addition, if a whole wall is formed in a tray shape by providing a wall with a short vertical dimension that surrounds the edge of the punching sheet 12A, water does not drop from the edge of the punching sheet 12A.

  As shown in FIG. 1, the collected water storage chamber 1 is provided with a powder removal filter 13 and a filtrate water storage tank 14 below the one side of the water tank 11. The water tank 11, the powder removal filter 13 and the filtered water storage tank 14 are partitioned by a vertical partition wall 1B. The upper end of the partition wall 1B is near the water surface of the water tank 11, and the collected water 56A from the water tank 11 crosses the partition wall 1B and the powder removal filter 13 is as much as the collected water 56A is fed into the water tank 11. Overflows up. As described above, since the collected water 56A is slowly dropped into the water tank 11, the inside of the water tank 11 is not stirred. Therefore, the collected water 56A is sent to the powder removal filter 13 from a portion close to the upper layer of the water tank 11.

  In general, since the specific gravity of suspended particulate matter (SPM) is smaller than that of water, it tends to concentrate on the surface of the aquarium 11. When the particle size of the suspended particulate matter (SPM) is small and easily dispersed, the flocculant can be dropped into the water tank 11. For example, a flocculant addition mechanism comprising a flocculant tank, a flocculant addition pipe extending from there to the punching sheet 12A, and an electromagnetic valve disposed in the middle and opened and closed by a timer or the like can be provided. Thus, a predetermined amount of the flocculant can be added every predetermined time.

  In the example shown in the figure, a diffuser plate 15A of the diffuser 15 is disposed at the bottom of the water tank 11, and a small amount necessary for separation of suspended particulate matter (SPM) through the air pipe 16 and the regulating valve 16A. Bubbles are generated. A panel heater 17 is disposed below the diffuser plate 15A. The air diffuser 15 and the panel heater 17 can be provided in the same configuration as will be described later as provided in the vaporizing chamber 3. However, the amount is much smaller than the amount of air blown for vaporization. In the specific example used in the test, the air diffuser 15 and the panel heater 17 were not installed in the water tank 11 of the collected water storage chamber 1, but when the air diffuser 15 was provided in the apparatus of this specific example, The air blowing rate can be set to 5 L / min, for example. Moreover, when heating the water tank 11 of the collection water storage chamber 1, and the water tank 31 of the vaporization chamber 3, the water temperature of the water tank 11 of the collection water storage chamber 1 can be kept at 35-36 degreeC, for example.

  As shown in the figure, the upper surface of the powder removal filter 13 is set at a position slightly lower than the upper end of the partition wall 1B, and the aggregate of suspended particulate matter (SPM) is thickly deposited on the powder removal filter 13. However, the suspended particulate matter (SPM) does not return to the water tank 11. Although not shown in the drawing, a drawer-type scraping mechanism is provided so that the deposited layer can be easily removed when the deposited layer on the powder removal filter 13 becomes a certain thickness or more. That is, when the handle or knob provided on the outer surface of the container 1A of the collected water storage chamber 1 is grasped and pulled, the scraping plate that is in contact with the partition wall 1B is pulled out and the deposited layer containing water is scraped out. It is. Alternatively, the deposited layer may be drawn out together with the powder removal filter 13. For example, the powder removal filter 13 may be composed of a plurality of layers of filter media sheets and pulled out together with the uppermost filter media sheet. The deposited layer discharged in this way is received in a suitable container and squeezed out of water, and then incinerated. As the powder removal filter 13, for example, a filter in which an inner layer made of glass fiber paper is sandwiched between wire meshes can be used.

  In the illustrated example, the filtrate water storage tank 14 is provided with float switches 14A-1 and 14A-2 at two height positions, respectively, and the water surface of the filtrate water storage tank 14 is above the float switch 14A-1. The water supply to the aquarium 11 is temporarily stopped or squeezed. Further, when the water surface falls to the position of the lower float switch 14A-2, the supply of water to the water tank 11 is resumed or the supply amount is increased. In a specific example, when the water surface reaches the position of the upper float switch 14A-1, the supply of the clean water 55 to the water tank 11 is stopped, and when the water surface reaches the position of the lower float switch 14A-2. In addition, the supply of the clean water 55 to the water tank 11 is resumed.

  The collected water 57 after filtration is once stored in the filtrate storage tank 14, and then collected by the collected water supply pipe 47 and the supply pump 47A provided in the middle of the center of the ceiling wall 3D of the vaporization chamber 3 Sent to the department.

  As with the collected water storage chamber 1, the vaporization chamber 3 is a container having a rectangular vertical cross section, and includes a water tank 31 that occupies most of the container, and a concentrated exhaust chamber 32 thereon. Further, the filtered collected water 57 that falls from the center of the ceiling wall falls into the center of a similar punching sheet 32A, and then gradually and uniformly over a wide area, the water surface of the aquarium 31. Fall down. The configuration, arrangement, and possible deformation of the punching sheet 32A are exactly the same as the punching sheet 12A in the collected water storage chamber 1 described above. However, the vaporizing chamber 3 is of a vertical type with a height dimension of at least twice the width and depth.

  At the bottom of the vaporizing chamber 3, a diffuser plate 35A that extends over almost the entire area of the bottom is disposed, and air taken from outside air by a compressor or the like is continuously fed into the vaporizing chamber 3. Thereby, fine bubbles continuously rise from almost the entire bottom of the water tank 31. The amount of air sent to the diffuser plate 35A of the diffuser 35 is appropriately adjusted by the flow rate adjusting valve 36A. The flow rate adjusting valve 36A is provided in the air pipe 36 extending from the compressor accumulator to the diffuser plate 35A. On the other hand, in the illustrated example, a panel heater 33 is provided between the bottom surface of the vaporizing chamber 3 and the diffuser plate 35A. The panel heater 33 performs uniform heating by maintaining the surface temperature at an appropriate temperature by the temperature adjustment function. However, in the specific example used in the test, heating is not performed. When actually heating, for example, by heating so that the water temperature of the water tank 31 is 36-37 ° C., various volatile organic compounds (VOC) generally contained in thinner etc. are efficiently removed. can do.

  In the illustrated example, the water 58 at the bottom of the vaporization chamber 3 is sent to the bottom of the collected water storage chamber 1 by the first return pipe 48 and the first return pump 48A. In this way, in the vaporization chamber 3, the water supplied from the top is drawn out at the bottom, and a gentle downward flow is generated. Bubbles rise against this flow, and the volatile organic compound (VOC) dispersed or dissolved in water mixes in the bubbles and rises with the bubbles. Therefore, the water 58 at the bottom of the vaporizing chamber 3 has a low concentration of volatile organic compounds (VOC). The water 58 at the bottom of the vaporization chamber 3 is once sent to the bottom of the collected water storage chamber 1 by the first return pipe 48 and the first return pump 48A and stored, and then the second return pipe 46 and the second return. It is sent to the nozzle 212 of the gas-liquid mixer 21 by the pump 46A. The water intake 46B of the second return pipe 46 and the discharge port 48B of the first return pipe 48 are provided close to each other, and the water 58 at the bottom of the vaporization chamber 3 is transferred to the gas-liquid mixer 21 as much as possible. To be sent. In addition, an appropriate partition wall is provided in the water tank 11 of the collected water storage chamber 1, and the water 58 storage portion at the bottom of the vaporization chamber 3 and the other portions can be completely or slightly distributed. It can be partitioned to any extent.

  In a specific example of the prototype test apparatus, the amount of water 56 for collection sent from the bottom of the collected water storage chamber 1 to the gas-liquid mixer 21 by the second return pipe 46 is 10 L / min. The amount of collected water 56A is also approximately 10 L / min. That is, the increase or decrease in the collected water storage chamber 1 due to this circulation is only evaporation in the gas-liquid separation cyclone 22 and the like, and is small. On the other hand, the amount of the collected water 56A sent to the vaporizing chamber 3 through the collected water supply pipe 47 is 30 L / min, and an amount of water 58 corresponding to this amount is collected through the first return pipe 48. Returned to However, since there are fluctuation factors such as the evaporation amount of water from the vaporizer 3, the amount of the returned water 58 is adjusted as appropriate. In particular, the capacity of the first return pump 48A is set to a value larger than 30 L / min, for example 45 L / min, and the first return pump 48A is set based on the detection of the float switch 34A installed at the upper end of the water tank 31 of the vaporization chamber 3. The return pump 48A can be turned on / off. That is, the amount of the returned water 58 can be appropriately adjusted by a simple control of operating the first return pump 48A only when the water level in the water tank 31 of the vaporizing chamber 3 becomes a certain level or more.

  As described above, since water used for collecting volatile organic compounds (VOC) circulates in the exhaust treatment apparatus, it is not necessary to use a large amount of water or to treat a large amount of sewage. However, during operation of the exhaust treatment device, components that are difficult to be vaporized among volatile organic compounds (VOC) may be gradually accumulated in the water in the vaporization chamber 3. In such a case, the exhaust treatment performance deteriorates, so that the water in the exhaust treatment device can be gradually replaced with clean water or the like. For this purpose, in the illustrated example, a drain pipe 49 is connected to the bottom of the water tank 31 of the vaporization chamber 3, and the amount of drainage 59 to be discharged is adjusted by the adjustment valve 49A in the middle. In addition, a water supply pipe 45 for supplying clean water (tap water or well water) 55 is connected to the bottom of the aquarium 11 of the collected water storage chamber 1, and supply of clean water 55 is performed by an electromagnetic valve 45A in the middle. The amount is adjusted. In the specific example, the amount of the drainage 59 is 1 to 2 L / min, and the supply amount of the clean water 55 is larger than the evaporation amount.

  The drainage 59 discharged from the drain pipe 49 can be purified to a level that can be discharged into a general river or ocean by a general biological purification process. Alternatively, the purified water can be used in place of the above-mentioned clean water 55. For example, water purified through a small-scale membrane separation activated sludge treatment device (MBR) can be used as the clean water 55. Instead of treating in this way, simply store the waste water 59 in a sealed tank, and send it to the vaporization chamber 3 when the load on the exhaust treatment device is small. You may make it isolate | separate. Further, for example, after the painting work in the painting booth 5 is completed, only the VOC vaporization separation devices 1 and 3 may be operated.

  Note that the drain pipe 49 is also used to prevent freezing by discharging the water in the water tank 31 when the operation is stopped in winter. Further, a similar drain pipe can be provided in the water tank 11 of the collected water storage chamber 1, thereby enabling discharge to the sewage at a predetermined speed and drainage when the operation is stopped. Although not shown in the drawing, various pipes can be provided with a heat insulating material or a heat insulation jacket as necessary.

  On the other hand, the first concentrated exhaust duct 43 is connected to the upper portion of the concentrated exhaust chamber 32 above the vaporization chamber 3, and the second concentrated exhaust is connected to the upper portion of the exhaust chamber 12 above the collected water storage chamber 1. A duct 42 is connected. The amount of the concentrated exhaust 53 discharged from the vaporizing chamber 3 through the first concentrated exhaust duct 43 is equal to the amount of the air 52 sent into the vaporizing chamber 3 by the diffuser 35 and is discharged from the second concentrated exhaust duct 42. The amount of the concentrated exhaust 51C is equal to the amount of the exhaust 51B sent from the gas-liquid separation cyclone 22 through the receiving part 24 and the vertical cylinder 24A together with the collected water 56A. In a specific example, the amount of air 52 sent and the amount of concentrated exhaust 53 discharged from the vaporization chamber 3 through the first concentrated exhaust duct 43 are 30 L / min, the amount of exhaust 51B sent, and the second concentrated The amount of the concentrated exhaust 51C discharged through the exhaust duct 42 is 5 L / min. That is, the total amount of concentrated exhaust gas is 35 L / min.

  In the illustrated example, the first and second concentrated exhaust ducts 43 and 42 are connected to the small combustion cylinder 6 after joining. The concentrated exhaust duct after the merging can be appropriately adjusted so that optimum combustion is performed by providing an air flow adjusting damper together with a backfire prevention valve. The small combustion cylinder 6 is composed of, for example, a vertical cylindrical combustion cylinder and a burner device inserted into the combustion cylinder from the side. The burner apparatus ejects a propane gas flame from the central portion of the combustion cylinder, for example. The interior of the combustion cylinder is at least 800 ° C. or higher, preferably 1200 ° C. or higher.

  In the specific example, the collected water storage chamber 1 has a rectangular parallelepiped shape having a width (W) of 600 mm, a depth (D) of 250 mm, and a height (H) of 700 mm, and the average amount of water in the water tank 11 is 80L. Further, the height from the average water surface to the ceiling of the water tank 11 is about 170 mm, and the average capacity of the concentrated exhaust chamber 12 is 25L. On the other hand, the vaporizing chamber 3 has a rectangular parallelepiped shape having a width (W) of 300 mm, a depth (D) of 410 mm, and a height (H) of 900 mm, and the average water volume of the water tank 31 is 90L. The height from the average water surface to the ceiling of the water tank 31 is about 170 mm, and the average capacity of the concentrated exhaust chamber 32 is 21 L. Further, the ratios of the widths and heights of the members 21 to 23 constituting the VOC collection device 2 and the widths and heights of the collected water storage chamber 1 are substantially as shown in FIG. Further, the depth dimensions of the members 21 to 23 constituting the VOC collection device 2 are the same as or less than the depth dimension 250 mm of the collected water storage chamber 1. That is, as shown in FIGS. 1 and 2, the VOC collection device 2 can be stored in a space that is the same as or less than the volume of the collected water storage chamber 1. It can be stored in the upper space.

The size of each member constituting the collected water storage chamber 1, the vaporization chamber 3, and the VOC collection device 2 in the exhaust treatment device 10 used for practical operation is the amount of the exhaust gas 51 to be treated is 4.5 of this specific example. It can be obtained by proportional calculation depending on how many times m ³ / min. In both the collected water storage chamber 1 and the vaporization chamber 3, the ratio of the volume of the concentrated exhaust chambers 12 and 32 to the amount of water (volume) of the water tanks 11 and 31 is in the range of 10 to 50%, particularly 20 to It can be appropriately adjusted within a range of 40%.

Therefore, for example, when processing an exhaust of 150 m ³ / min, all dimensions need only be tripled and can be accommodated in a space having a height of 4 m, a width of 4 m, and a depth of 1.5 m.

  Further, with the exhaust treatment device 10 of the present embodiment, for example, the concentration of the volatile organic compound (VOC) can be reduced by 30%. If the exhaust gas to be treated is directly burned, in order to reduce 30% of volatile organic compounds (VOC), it is necessary to burn the exhaust gas to 30%. On the other hand, according to the present embodiment, in order to obtain the same reduction effect with respect to the volatile organic compound (VOC), the combustion treatment may be performed by about 0.8%. Therefore, the fuel cost required for combustion, and the capacity and size of the combustion processing unit can be reduced to about 1/120 compared to simple combustion processing.

  In order to improve the removal rate of volatile organic compounds (VOC), it is only necessary to connect a plurality of exhaust treatment apparatuses 10 of this embodiment in series. For example, when two units are connected in series, the volatile organic compound (VOC) becomes 70% × 70% = about 0.5 times. When 4 units are connected in series, it is about 0.25 times, and when 8 units are connected in series, it is about 0.058 times (5.8%). Even if the emission standards become stricter, it is sufficient to connect 4 to 8 units in series, so the fuel cost may be 4 to 8% or less in the case of simple combustion processing. it can. Moreover, since the installation space for one unit is small, even if 4 to 8 units are installed, it does not occupy that much space. In addition, it is estimated that the cost of a processing apparatus can be significantly reduced when only one or two units are installed as compared with a conventional adsorption method or a combustion method.

  Next, a specific configuration of the VOC collection device (exhaust gas purification system) 2 shown in FIGS. The gas-liquid mixer 21 is configured inside a cylindrical or cuboid container 21A around a vertical axis. An opening is provided in a part of the ceiling surface of the container 21A and one side wall of the lower part, and the upper opening is connected to the exhaust duct 41 through a first cup-shaped connecting duct part 41B having a downward-facing cup having an inlet in the side part. Connect to the discharge end. The lower part of the container 21A forms the second connection duct part 22A, and the gas-liquid separation cyclone 22 is connected to the opening of one side wall of the second connection duct part 22A.

  A plurality of nozzles 212 are arranged at the upper end in the container 21A. For example, when the horizontal cross section of the container 21A is rectangular, 18 nozzles 212 having the same configuration and dimensions are arranged in the same horizontal plane so as to form 6 rows in the front-rear direction and 3 rows in the left-right direction. Is done. Each nozzle 212 sprays the water 56 supplied from the contact water supply pipe 46 at a wide angle, whereby the water 56 for collection is collected almost evenly over the entire horizontal cross section of the cylindrical container 21A. Supplied. In the specific example used in the test, the inner diameter of the nozzle 212 is about 1 mm, but it can be appropriately set to a value in the range of 1 to 5 mm, for example.

  Below the nozzle 212, four plate-like porous bodies 211-1 to 211-4 made of a coarse and thick nonwoven fabric are provided. The distance from the tip of the nozzle 212 to the upper surface of the first-stage plate-like porous body 211-1 is set to a distance necessary for the sprayed collection water 56 to spread as uniformly as possible over the entire surface. Is done.

  Each plate-like porous body 211 has a size and shape substantially equal to the horizontal cross section of the container 21A. As the plate-like porous body 211, for example, various types of “General Regeneration” and “General Disposable” varieties of “Viledon (trademark)” air filter manufactured by Japan Vilene can be used. Specific test equipment includes “PS / 600” for “general regeneration” (polyester / modacrylic, thickness 20 ± 3 mm, initial pressure loss 93 Pa, “average collection efficiency (JIS 15 types, colorimetric method type 3)” 82%) was cut into suitable dimensions and shapes.

As shown in FIGS. 3 to 4, each plate-like porous body 211 is supported by a punching sheet 213 and a frame-like metal fitting 214. In a specific example, the punching sheet 213 is “Punching Metal” manufactured by Asahi Stainless Steel Co., Ltd., and is a stainless steel plate having a thickness of 0.5 mm, in which circular holes 213A having a diameter of 3 mm are evenly opened. The pitch between the center points in the same row is 5 mm, the positions of the holes are staggered between adjacent rows, and the aperture ratio is 32.6%. The horizontal dimension (width and depth) of the punching sheet 213 is substantially the same as that of the plate-like porous body 211. The frame-shaped metal fitting 214 has an L-shaped vertical cross section in each part, and in a specific example, the dimension protruding in a shelf shape is 10 mm inside, and this inside has an effective cross-sectional area of about 325 cm ² . . That is, in a specific example, each plate-like porous body 211 has an effective cross-sectional area of about 325 cm ² for passage of the exhaust gas 51 and the collecting water 56, and the exhaust gas 51 of 4500 L / min passes through here. The amount of water 56 supplied from the nozzle 212 is 10 L / min, and the volume ratio to the exhaust 51 is 1/450. Further, in the specific example, an interval of about 10 mm is provided between the punching sheet 213 and the next-stage plate-like porous body 211.

  On the other hand, as shown in FIG. 1, the demister 23 is configured such that a collision demister 23A and a passing demister 23C are integrally formed. The collision type demister 23A is a portion directly connected to the tip of the discharge cylinder 243 of the gas-liquid separation cyclone 22, and is disposed at a predetermined distance from the tip of the discharge cylinder 243 (about 10 cm in the test apparatus of the specific example). It consists of a vertical wall surface 23B and a plate-like porous body 231 for airflow collision arranged so as to cover the entire surface. In a specific example, the plate-like porous body 231 is obtained by cutting out the above-mentioned Japan Vilene “Filledon (trademark)” “PS / 600” into a rectangular shape with dimensions of 250 mm × 250 mm.

In the passing demister 23C, a plurality of plate-like porous bodies 232 for passing airflow are arranged in the horizontal direction in an exhaust chamber having a large horizontal cross-sectional area such as a short cylindrical shape or a short rectangular tube shape. In the illustrated example, the end portion of the plate-like porous body 232 for airflow passage covers the upper end portion of the plate-like porous body 231 for airflow collision on the wall surface extending upward from the vertical wall surface 23B. ing. In a specific example, since the passage area of the plate-like porous body 232 for airflow passage is 720 cm ² and the exhaust 51A of about 4.5 m ³ / min passes, the wind speed is about 6 m / min = about 0.1 m / sec. It is. Specific examples of the plate-like porous body 232 for passing an air current include the above-mentioned “Viledon (trademark)” “PS / 600” of Japan Vilene Co., Ltd. -90-50 was used in combination. Mist captured by the plate-like porous body 232 for airflow passage is considerably small, but flows down through the plate-like porous body 231 for airflow collision. The mist captured by the collision type demister 23A and the passing type demister 23C becomes a water droplet and is sent to the collected water storage chamber 1 through a capillary pipe (not shown).

  Next, the configuration of the gas-liquid separator 22 will be described with reference to FIGS. The gas-liquid separator 22 has a small diameter at one end of an outer cylindrical member 221 formed in a cylindrical shape, as shown in FIG. 5 in a perspective view with a part broken away, and in FIG. 6 in a vertical sectional view along the axial direction. An inflow port 222 is formed, and a small-diameter cylinder 223 (actually, a section having a pair of circular arcs) is disposed on the downstream side of the inflow port 222 with a little space from the end of the inflow port 222. As can be understood from FIG. 7 which is a vertical sectional view in the transverse direction seen from the back surface (downstream surface), the circumferential surface of the small diameter cylinder 223 extends over the rear end surface 221A of the outer cylinder member 221. Two openings 223A having a predetermined width are formed in the longitudinal direction so as to face each other. From one end of the opening 223A, an arcuate guide piece is formed outwardly in the tangential direction of the small-diameter cylinder 223 so as to cover the opening 223A. 224 is extended in the same direction, and its end edge is brought into contact with the inner surface side of the outer cylinder member 221 to form a guide channel 225.

  The end surface on the inflow side of the small-diameter cylinder 223 is closed by a shielding plate 226, and an opening portion on the inflow side of the gap between the guide piece 224 serving as the guide channel 225 and the small-diameter cylinder 223 is also included in the shielding plate 226. As a result, the exhaust gas flowing in from the inlet 222 side comes into contact with the shielding plate 226 in the outer cylinder member 221) and changes its flow in the circumferential direction in the outer cylinder member 221. Further, the guide channel 225 flows along the guide piece 224, and flows into the small-diameter cylinder 223 as a rotating flow and flows downstream.

  On the downstream side of the outer cylindrical member 221, a plurality of large-diameter cylindrical bodies 227 and 228 having a diameter slightly smaller than that of the outer cylindrical member 22 are arranged adjacent to each other, and a partition wall that partitions the cylindrical bodies 227 and 228 A communication tube 240 having the same diameter as that of the small-diameter cylinder 223 is interposed so as to pass through the central portion of 229 and communicate with both cylinders 227 and 228.

  Further, as shown in FIG. 8, the bottom surface of the cylindrical bodies 227 and 228 positioned before and after the communication tube 240 has a transmission hole having a width dimension about the diameter of the small cylinder 223 in the longitudinal direction. 241 is provided, a liquid receiving tank 242 is disposed below the cylindrical bodies 227 and 228 communicating with the permeation hole 241, and an exhaust gas outlet 243 is provided at the other end on the most downstream side of the cylindrical body 228. is doing.

  With the above configuration, the gas-liquid mixed exhaust gas to be purified that has flowed into the outer cylinder 221 from the inflow port 222 is brought into contact with the shielding plate 226 as indicated by an arrow, thereby the peripheral edge in the outer cylinder 221 Is further guided to the guide piece 224 that is in contact with the inner surface of the outer cylinder, flows into the guide channel 225, and flows into the small-diameter cylinder 223 through the opening 223A, so that a rotational force is applied. The vortex flows into the cylindrical body 227 from the end of the small diameter cylinder 223).

  The swirled exhaust gas forms a cyclone due to expansion and centrifugal force when it flows into the cylindrical body 227, and volatile organic compounds (VOC) and suspended particulate matter ( The collected water 56A that adsorbs (SPM) and the exhaust gas 51A purified by this adsorption are separated. The collected water 56A falls from the permeation hole 241 to the lower liquid receiving tank 242 by centrifugal force and gravity.

  The collected water 56A that has fallen into the liquid receiving tank 242 is guided to the collected water receiving section 24 further downstream by the pressure in the cylindrical body 227 and the gravity of the liquid itself. And will not be blown up by swirls.

  The size of the gas-liquid separation cyclone 22 is such that, in the above specific example, the inner diameter of the outer cylinder 221 is 170 mm, the inner diameters of the cylindrical bodies 227 and 228 are 150 mm, and the total length excluding the cylindrical portions of the inlet 222 and outlet 243 is 450mm.

  Hereinafter, an exhaust treatment apparatus 10 ′ of the second embodiment will be described with reference to FIG. The exhaust treatment apparatus 10 ′ of the second embodiment differs from the exhaust treatment apparatus 10 of the first embodiment only in that a mechanism for collecting the suspended particulate matter (SPM) is omitted. That is, in the collected water storage chamber 1, there is no powder removal filter 13 and filtered water storage tank 14, and no air diffuser 15 is provided. Moreover, a flocculant addition mechanism is not provided. Further, the pair of float switches 14A-1 and 14A-2 are provided so as to detect the water level of the water tank 11 that directly stores the collected water 56A, and based on this detection, the solenoid valve 45A of the water supply pipe 45 Control is performed. In the specific example, the supply of the clean water 55 through the clean water pipe 45 is turned on and off as in the specific example of the first embodiment. In the illustrated example, a strainer 46C is provided in the middle of the second return pipe 46, and clogging of the nozzle 212 is surely prevented by removing dust (iron rust, etc.) of 1.0 mm or more.

  In the example shown in FIG. 9, the partition wall 1 </ b> B is omitted, but by providing this, the upper layer portion of the water tank 11 can be preferentially sent to the vaporizing chamber 3. In addition, when it is not necessary to remove the suspended particulate matter (SPM), it is possible to omit the powder removal filter 13 from the apparatus shown in FIG. The vaporization of organic organic compounds (VOC) can also be promoted.

  When there are few suspended particulate matter (SPM) in the exhaust gas 51 to be treated, it is sufficient to use the exhaust treatment apparatus 10 ′ of the second embodiment. If some suspended particulate matter (SPM) is included, the concentration of suspended particulate matter (SPM) will gradually increase in the water in the collected water storage chamber 1 and vaporization chamber 3, There is no problem if all the internal water is replaced at the end and treated at a sewage treatment facility.

<Test results>
Exhaust from a small rubber molding booth in actual operation was treated with the test apparatus and conditions of the above-described specific example, and the concentration of volatile organic compounds (VOC) before and after treatment was measured by a gas chromatograph. In this molding booth, rubber molding is performed between a pair of molds with a tact time of 4 minutes. Therefore, when the mold is opened, the emission of volatile organic compounds (VOC) increases and then gradually decreases. Therefore, when sampling the exhaust gas and storing it in a fluororesin (PTFE) bag, the operation of inhaling at a uniform rate over 2 minutes was performed twice. That is, it is considered that the average concentration of volatile organic compounds (VOC) was measured by performing almost continuous and uniform inhalation for a total of 4 minutes. Note that the timing at which sampling is directly performed from the exhaust duct of the rubber molding booth and the timing at which sampling is performed from the exhaust duct of the exhaust treatment apparatus 10 are not matched, and are not matched with the tact time of rubber molding. Moreover, the water in the water tanks 11 and 31 was not heated, and was about 25 ° C., which was slightly lower than the outside air temperature of 28 ° C. at the time of measurement.

The following shows the results of gas chromatograph measurements taken by the Environmental Analysis Research Laboratory Co., Ltd. during a test operation on September 14, 2009. As shown in the right end of the table, a decrease rate of 37% was observed when viewed in total for the four volatile organic compounds.

  In Table 1 above, the concentration is an average value of two measurements by gas chromatograph. In parentheses are the first measurement (first half of 4 minutes) and the second measurement (second half).

  First, there is a large difference between the two measured values in the exhaust before processing. The evaporation of the solvent (volatile organic compound) is a lot when the mold is opened within the above molding tact time. This is probably because the boiling point and the vapor pressure during heating differ among the solvent species, and thus there is a difference in the transpiration rate after opening the mold. For example, the first measurement value was high for methanol having a low boiling point, whereas the second measurement value was high for toluene having a high boiling point.

On the other hand, in the exhaust after treatment, in addition to the difference in easiness of evaporation in the molding booth, there are effects such as ease of dissolution in water and difference in ease of separation after dissolution. It is thought that. Table 2 below shows the literature values of the vapor pressure at 25 ° C. and the solubility in water at around 25 ° C. for each solvent type of volatile organic compound (VOC).

  The reason why the decrease rate of methanol was as high as 60% is considered to be because it is most soluble in water and has a high vapor pressure around 25 ° C. The reason why the reduction rate of methyl ethyl ketone (MEK) was 40% and was next to methanol was considered to be because it was relatively easy to dissolve in water and the vapor pressure at around 25 ° C was high. The reason why the decrease rate of toluene was relatively low at 32% is considered to be due to low solubility in water and low vapor pressure around 25 ° C.

  The main cause of the decrease in methyl isobutyl ketone (MIBK) was 16%, which seems to be due to the low vapor pressure around 25 ° C.

  Although data is not shown, according to a preliminary experiment, when the water temperature of the water tank 31 in the vaporization chamber 3 is increased, the reduction rate due to the treatment in the exhaust treatment device 10 is rapidly improved around 35 ° C. . Therefore, it is known that maintaining the water temperature in the water tank 31 at 35 ° C. to 40 ° C. greatly promotes evaporation of the above four kinds of organic compounds (VOC) including methyl isobutyl ketone, and can greatly improve the processing efficiency. It was.

Table 3 below shows the results of sampling and measurement from wastewater during the test operation on September 14, 2009 by the Environmental Analysis Research Laboratory. At this time, sampling was performed when it was determined that a certain state was reached after the exhaust treatment device 10 was continuously operated and drainage 59 of about 1.5 L / min was continuously discharged from the drain pipe 49.

  As is known from the above measurement results, it is known that the waste water is discharged to a general sewage treatment facility, particularly a public sewage network, and has no problem at all. The upper limit of BOD according to general sewage discharge standards is 600 mg / L, which is 68 mg / L, about 1/9 of that. Therefore, by discharging a certain amount as the drainage 59, the burden on the exhaust treatment apparatus 10 can be reduced. For example, when the treatment load temporarily increases, it is also possible to increase the discharge amount of the waste water 59. In this case, by adjusting the capacity of the exhaust treatment device 10 during normal operation, the device cost, installation space, In particular, the cost and installation space of the vaporizer 3 can be prevented from becoming too large.

1 Collected water storage chamber 11 Water tank 12 Exhaust chamber 13 Powder removal filter 14 Filtration water storage tank
15 Air diffuser 17 Panel heater 2 Exhaust gas purification system 21 Gas-liquid mixer
211 Plate-like porous body 212 Nozzle 213 Punching sheet
22 Horizontal gas-liquid separation cyclone 23 Demister 231, 232 Plate-like porous body
3 Vaporization chamber 31 Water tank 32 Concentration exhaust chamber 33 Panel heater 35 Air diffuser
41 Exhaust duct 41A Blower 42 Second concentrated exhaust duct 43 First concentrated exhaust duct
45 Water supply pipe 46 Second return pipe (supply pipe to nozzle)
47 Collected water supply pipe (supply pipe to vaporization chamber) 48 1st return pipe 5 Painting booth
51 Exhaust from painting booth 51A Exhaust after treatment 51C, 53 Concentrated exhaust
55 Water 56 Water for collection 56A Water collected (water after collection)

Claims (10)

Exhaust (51) containing volatile organic compounds (VOC) is contacted and mixed with water (56), thereby collecting and retaining volatile organic compounds (VOC) in water (56) at least partially. A gas-liquid mixer (21);
A gas-liquid separator (22) disposed downstream of the gas-liquid mixer (21);
Receives and stores the collected water (56A) discharged from the gas-liquid separator (22) and at least partially vaporizes the volatile organic compound (VOC) retained in the collected water (56A). Vaporizing and separating device for separating from water,
Water return system for collection (48, 48A, 46, 46A) that at least partially returns the water in the vapor separation device to the gas-liquid mixer (21) for reuse as water for collection (56) An exhaust treatment apparatus characterized by comprising:   The vaporization separation device is configured such that the collected water (56A) discharged from the gas-liquid separator (22) has a smaller amount of air (52) than the exhaust (51) and / or a part of the exhaust (51) ( 51B) is in contact with the concentrated exhaust generation system (1,3), which produces concentrated exhaust (53,51C) with a higher concentration of volatile organic compounds (VOC) than the original exhaust (51). The exhaust treatment device according to claim 1. Exhaust (51) containing volatile organic compounds (VOC) is contacted and mixed with water (56), thereby collecting and retaining volatile organic compounds (VOC) in water (56) at least partially. A gas-liquid mixer (21);
A gas-liquid separator (22) disposed downstream of the gas-liquid mixer (21);
A small amount of air (52) and / or a part (51B) of the exhaust (51) is brought into contact with the collected water (56A) discharged from the gas-liquid separator (22). And an exhaust gas processing system (1, 3) for generating an exhaust gas (53, 51C) having a higher concentration of volatile organic compounds (VOC) than the original exhaust gas (51).   The gas-liquid mixer (21) supplies a plate-like porous body (211) made of a plate-like fiber aggregate or foam capable of capturing particles having a particle diameter of 10 μm or more, and water (56) over the entire surface. The exhaust treatment device according to any one of claims 1 to 3, wherein the exhaust treatment device comprises a nozzle (212) or other water supply means.   A plurality of plate-like porous bodies (211-1 to 211-4) are arranged in the passage of the exhaust gas (51) in the gas-liquid mixer (21), and each plate-like porous body (211) is 0.5 mm or more. Is supported from the downstream side by a punching sheet (213) having a uniform diameter of the hole, and a predetermined interval is provided between the punching sheet (213) and the plate porous body (211) at the next stage. The exhaust treatment device according to any one of claims 1 to 4, wherein   The exhaust gas treatment device according to any one of claims 1 to 5, wherein the gas-liquid separator (22) is a horizontal gas-liquid separation cyclone (22). The concentrated exhaust generation system (1, 3) includes a collected water storage chamber (1) for storing collected water (56A), and a vaporization chamber (3) having a water tank (31) and an air diffuser (35). Become
The collected water stored in the collected water storage chamber (1) is sent to the upper part of the water tank (31) in the vaporization chamber (3), and bubbles are sent to the lower part of the water tank (31) through the air diffuser (35). The exhaust treatment device according to any one of claims 1 to 6, wherein the concentrated exhaust (53) is discharged from the upper part of the vaporization chamber (3) through the discharge duct (43).   The water (58) at the lower end of the water tank (31) in the vaporization chamber (3) is returned to the lower part of the water tank (11) in the collected water storage chamber (1) and is returned to the gas-liquid mixer (21). 8. The exhaust treatment device according to claim 7, wherein the exhaust treatment device is used as water (56) sent to collect volatile organic compounds (VOC).   A powder removal filter (13) that receives water overflowing from the water tank (11) into the collected water storage chamber (1) and separates aggregates of the suspended particulate matter (SPM) from the water, and a powder removal filter The exhaust treatment apparatus according to claim 7 or 8, further comprising a storage tank (14) for storing filtered water that has passed through (13) and / or a pipe (47) for discharging the filtered water. Exhaust (51) containing volatile organic compounds (VOC) is contacted and mixed with water (56), thereby collecting and retaining volatile organic compounds (VOC) in water (56) at least partially. A gas-liquid mixing process;
Performing gas-liquid separation downstream of the gas-liquid contact location;
Volatile by contacting the collected water (56A) discharged from the gas-liquid separation location with a smaller amount of air (52) than the exhaust (51) and / or part (51B) of the exhaust (51). Generate concentrated exhaust (53,51C) with organic compound (VOC) concentration higher than the original exhaust (51), or store the collected water (56A), and then apply heating, decompression, or stirring. A vaporization separation step that at least partially separates the volatile organic compound (VOC) by generating a concentrated vapor containing volatile organic compound (VOC) in the water vapor;
An exhaust treatment method comprising: a step of returning at least partially the water that has undergone the vaporization separation step to the gas-liquid mixer (21) so as to be reused as water for collection (56).

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