JP2007326007A - Exhaust gas treating method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas treating method and an apparatus absorbing organic compounds into liquid for removing. <P>SOLUTION: Washing water containing microorganisms is circulated and sprayed into a scrubber vessel 2 for passing exhaust gas therethrough by a water spraying means 9 to dissolve the organic compounds in the exhaust gas into the washing water, and the washing water is stored in a primary treatment tank 3 integrally formed at the lower part of the scrubber vessel 2. The microorganisms are activated by introducing micro-nano bubbles to decompose the organic compounds by the microorganisms, and the washing water delivered from the primary treatment tank 3 is stored in a secondary treatment tank 4. The microorganisms are activated by introducing micro-nano bubbles to further decompose remaining organic compounds and decomposed matter thereof by the microorganism to return the washing water to the primary treatment tank 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust gas treatment method and an exhaust gas treatment apparatus.

  Conventionally, as a method for treating exhaust gas containing an organic compound, particularly volatile organic compound (VOC), adsorption by activated carbon or combustion by exhaust gas has been put into practical use.

  In general, exhaust gas treatment methods with low environmental impact include a method of contacting exhaust gas with liquids such as water, acid and alkali solutions with a scrubber to absorb pollutants. However, volatile organic compounds are sufficiently removed. Nothing that could be done was provided.

  Therefore, an object of the present invention is to provide an exhaust gas treatment method and an exhaust gas treatment device that can absorb and remove an organic compound in a liquid.

  In order to solve the above problems, an exhaust gas treatment method according to the present invention stores cleaning water containing microorganisms in a primary treatment tank, circulates and sprays the cleaning water on exhaust gas, and converts organic compounds in the exhaust gas into cleaning water. Dissolving, introducing micro-nano bubbles into the primary treatment tank, activating the microorganisms to decompose the organic compound in the wash water, introducing the wash water of the primary treatment tank into the secondary treatment tank, A method of introducing micro-nano bubbles into the secondary treatment tank, activating the microorganism, further decomposing the organic compound and its decomposition product in the wash water, and then returning the wash water to the primary treatment tank; To do.

  According to this method, in the primary treatment tank, the organic compound dissolved in the washing water is decomposed by microorganisms, and the organic compound that cannot be completely decomposed in the primary treatment tank and the decomposition product thereof are further decomposed in the secondary treatment tank. The organic compound can be reliably treated.

  Furthermore, the exhaust gas treatment apparatus according to the present invention is a scrubber container provided with sprinkling means through which exhaust gas is inserted, circulating cleaning water containing microorganisms into the exhaust gas, and dissolving the organic compound in the exhaust gas into the cleaning water; A first micro / nano bubble generating device that is integrally formed under the scrubber container, stores the cleaning water, and introduces micro / nano bubbles into the stored cleaning water, and decomposes the organic compound by the microorganism 1 A secondary treatment tank and a secondary treatment for storing the wash water derived from the primary treatment tank and further decomposing the remaining organic compound and its decomposition product by the microorganisms and then returning them to the primary treatment tank It shall have a tank.

  According to this configuration, in the primary treatment tank, the organic compound dissolved in the washing water in the scrubber vessel is decomposed by the microorganisms, and the organic compound that cannot be completely decomposed in the primary treatment tank and the decomposition product are decomposed in the secondary treatment tank. Furthermore, since it decomposes | disassembles, an organic compound can be processed reliably.

  Moreover, the waste water treatment apparatus of this invention WHEREIN: The said primary treatment tank may hold | maintain activated carbon in the said wash water to store.

  According to this structure, microorganisms propagate on activated carbon and actively decompose organic compounds.

  Moreover, the waste water treatment apparatus of this invention WHEREIN: The said 2nd processing tank may hold | maintain activated carbon in the said wash water to store.

  According to this configuration, since the microorganisms propagate on the activated carbon, the decomposition of the organic compound in the secondary treatment tank can be promoted.

  Moreover, the waste water treatment apparatus of this invention WHEREIN: The said secondary treatment tank may be equipped with the 2nd micro nano bubble generator which introduces a micro nano bubble into the stored said wash water.

  According to this configuration, the microorganisms can be activated by the secondary treatment tank micro-nano bubbles, and the decomposition of the organic compound can be promoted.

  In the wastewater treatment apparatus of the present invention, the second micro / nano bubble generating device may include a submerged pump type microluna bubble generator.

  According to this configuration, it is easy to install the micro / nano bubble generator, and a large amount of micro / nano bubbles can be introduced.

  Moreover, the waste water treatment apparatus of this invention WHEREIN: The said primary treatment tank is equipped with the 1st TOC measuring device which measures the total organic carbon density | concentration of the said wash water to store, Furthermore, it measures with the said 1st TOC measuring device. According to the total organic carbon concentration, a transfer flow rate control means for adjusting a flow rate of the washing water transferred from the primary treatment tank to the secondary treatment tank may be provided.

  According to this configuration, only when the total organic carbon concentration in the primary treatment tank increases, a part of the washing water is transferred to the secondary treatment tank to perform the secondary treatment, and energy consumption in the secondary treatment tank is reduced. Can be suppressed. In addition, the higher the total organic carbon concentration, the larger the amount of cleaning water transferred to the secondary treatment tank. Can be kept below a certain concentration. Thereby, in the scrubber container, the organic compound in the exhaust gas can be dissolved in the cleaning water without leaving it.

  In the wastewater treatment apparatus of the present invention, the transfer flow rate control means adjusts the opening of an automatic control valve provided in a transfer flow path for transferring the wash water from the primary treatment tank to the secondary treatment tank. It may be a means.

  According to this structure, the flow volume of the washing water transferred from the primary treatment tank to the secondary treatment tank can be automatically adjusted.

  Moreover, the waste water treatment apparatus of this invention WHEREIN: The said secondary treatment tank is equipped with the 2nd TOC measuring device which measures the total organic carbon density | concentration of the said wash water to store, and also measures with the said 2nd TOC measuring device. A return flow rate control means for adjusting the flow rate of the washing water to be returned to the primary treatment tank according to the total organic carbon concentration may be provided.

  According to this configuration, when the organic compound cannot be sufficiently decomposed in the secondary treatment tank, the amount of cleaning water returned to the primary treatment tank is reduced so that the primary treatment tank is supplied with makeup water. Thus, it is possible to prevent the total organic carbon concentration of the cleaning water in the primary treatment tank from increasing.

  Further, in the wastewater treatment apparatus of the present invention, the return flow rate control means adjusts the opening of an automatic control valve provided in a return flow path for returning the wash water from the secondary treatment tank to the primary treatment tank. It may be a means.

  According to this configuration, it is possible to automatically adjust the flow rate of the cleaning water returned from the secondary treatment tank to the primary treatment tank.

  Moreover, since the wastewater treatment apparatus of the present invention can be decomposed by dissolving the organic organic compound in the washing water, the organic compound contained in the exhaust gas may contain a volatile organic compound.

  According to the present invention, the washing water in which the organic compound in the exhaust gas is dissolved is subjected to the two-stage microbial treatment in the primary treatment tank and the secondary treatment tank. Organic compounds in the exhaust gas can be removed.

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 shows an exhaust gas treatment apparatus 1 according to a first embodiment of the present invention. The exhaust gas treatment apparatus 1 includes a scrubber container 2, a primary treatment tank 3 formed integrally with the lower side of the scrubber container 2, and a secondary treatment tank 4.

  The scrubber container 2 is a container in which a bottom plate 5 made of a porous plate is provided at the lower end and an exhaust pipe 6 is provided at the upper end. Inside the scrubber container 2, a filling layer 8 is formed on the bottom plate 5 with a plastic filler 7, and a spray nozzle for spraying cleaning water containing aerobic microorganisms from above onto the filling layer 8. Watering means 9 is provided.

  An exhaust gas flow path 10 is connected to the boundary between the scrubber container 2 and the primary treatment tank 3, and exhaust gas is sent into the exhaust gas treatment apparatus 1 by an exhaust fan 11 so that the scrubber container 3 is inserted.

  The plastic filler 7 is commercially available as a filler for an apparatus for liquid-cleaning gas, and forms a continuous void, so that the packed bed 8 allows fluid to pass through without significant pressure loss. For this reason, the exhaust gas sent from the exhaust gas flow path 10 passes through the bottom plate 5 and the packed bed 8 and is discharged to the outside from the exhaust pipe 6.

  The primary treatment tank 3 collects and stores the wash water sprayed from the water spraying means 9, and stores the water stored in the water spray pump 13 that sucks out the stored wash water and sends it to the water spraying means 9 through the circulation channel 12. And a first micro / nano bubble generator 14 for introducing micro / nano bubbles into the washing water. The primary treatment tank 3 has a perforated plate 15 as a bottom and a side wall surrounded by a net-like net 16 so that the cleaning water can freely enter and leave the storage chamber 17 so as to be submerged in the stored cleaning water. The activated carbon 18 is stored inside the storage chamber 17. Further, the primary treatment tank 3 has a first TOC measuring device 19 that measures the total organic carbon concentration of the stored wash water.

  The micro / nano bubble generator 14 sucks out the cleaning water in the primary treatment tank 3 by the circulation pump 20 and injects it into the micro bubble generator 21, and shears the self-supplied air through the control valve 22 by the flow rate of the cleaning water. This is a self-contained micro-nano bubble generator that generates micro-nano bubbles (fine bubbles) and discharges them together with cleaning water.

  Further, the exhaust gas treatment apparatus 1 is branched from the circulation flow path 12 and washed from the secondary treatment tank 4 to the primary treatment tank 3 by a transfer flow path 23 for transferring a part of the washing water to the secondary treatment tank 4. And a return flow path 24 for returning water. The circulation flow path 12 and the transfer flow path 23 are respectively provided with automatic control valves 25 and 26, and the flow rate of the wash water sent to the sprinkling means 9 and the flow rate of the wash water sent to the secondary treatment tank 4 are respectively set. It can be adjusted independently. The return flow path 24 is also provided with an automatic adjustment valve 27 so that the flow rate of the cleaning water returned from the secondary treatment tank 4 to the primary treatment tank 3 can be adjusted.

  The secondary treatment tank 4 stores the wash water transferred from the primary treatment tank 3, and is washed by surrounding the side portion with a net-like net 29 so as to be submerged in the stored wash water. A storage chamber 30 in which water can freely enter and exit is formed, and activated carbon 31 is stored inside the storage chamber 30. Further, the secondary treatment tank 4 has a second micro / nano bubble generator 32 and has a second TOC measuring device 33 for measuring the total organic carbon concentration of the stored wash water. Further, the secondary treatment tank 4 includes a water distribution pipe 34 through which the cleaning water overflows.

  The micro / nano bubble generation device 33 is a forced air intake type device, and supplies air to the submersible pump type micro / nano bubble generator 35 supported in the washing water stored in the secondary treatment tank 4 by a blower 36 to generate micro / nano bubbles. Is generated. The submersible pump type micro / nano bubble generator 35 is easy to install and can generate a large number of micro / nano bubbles.

  Further, the exhaust gas treatment apparatus 1 automatically transfers the opening degree of the automatic control valves 25 and 26 in accordance with the total organic carbon concentration of the cleaning water in the primary treatment tank 3 measured by the first TOC measuring device 19. The flow rate control means 37 and the return flow rate control means 38 for automatically adjusting the opening degree of the automatic control valve 27 according to the total organic carbon concentration of the wash water in the secondary treatment tank 4 measured by the second TOC measuring device 33. And have.

Then, the effect | action of the waste gas processing apparatus 1 which consists of the above structure is demonstrated.
Exhaust gas containing organic compounds, particularly volatile organic compounds such as isopropyl alcohol, acetone, butyl acetate, etc., is introduced into the exhaust gas treatment device 1 from the exhaust gas flow path 10 and stitches the gap between the plastic fillers 7 in the packed bed 8. Rise. At this time, the organic compound contained in the exhaust gas is dissolved in the cleaning water by being sprayed from the water spray means 9 and coming into contact with the cleaning water that is sewn through the gap of the plastic filler 7 and descends.

  The washing water in which the organic compound is dissolved is recovered and stored in the primary treatment tank 3. In the cleaning water stored in the primary treatment tank 3, activated carbon 18 is held in the storage chamber 17, and the organic compound dissolved in the packed bed 8 is adsorbed by the activated carbon 18. Moreover, microorganisms propagate on the activated carbon 18 and decompose the adsorbed organic compounds. Furthermore, micro-nano bubbles are introduced into the cleaning water stored in the primary treatment tank 3 by the micro-nano bubble generator 14, and the microorganisms are activated and the organic compounds adsorbed on the activated carbon 18 and the organics dissolved in the cleaning water are damaged. Decomposes the compound. When the adsorbed organic compound is decomposed, the activated carbon 18 is regenerated so that the organic compound can be adsorbed again.

  The amount of the organic compound dissolved in the washing water can be confirmed as the value of the total organic carbon concentration measured by the TOC measuring device 19. When the total organic carbon concentration of the wash water in the primary treatment tank 3 is low, the transfer flow rate control means 37 fully closes the automatic control valve 26 and allows the wash water sent from the water spray pump 13 to be led to the transfer flow path 23. Instead, only circulation spraying by the water spray means 9 through the circulation channel 12 is performed. Further, the phase flow rate control means 37 controls the opening degree of the automatic adjustment valve 25 so that the amount of cleaning water sprayed from the watering means 9 is constant regardless of the opening degree of the automatic adjustment valve 26.

  When the concentration of the organic compound in the exhaust gas is low, the organic compound dissolved in the cleaning water from the exhaust gas can be sequentially decomposed in the primary treatment tank 3 to maintain the total organic carbon concentration below a certain value. If the concentration of the organic compound in the exhaust gas increases, the decomposition of the organic compound cannot catch up, and the total organic carbon concentration of the cleaning water in the primary treatment tank 3 increases.

  For example, when a large amount of isopropyl alcohol is continuously dissolved in the washing water, isopropyl alcohol is decomposed to some extent, but the concentration of acetone, which is a decomposition product generated by the primary decomposition of isopropyl alcohol, significantly increases, Increase overall organic carbon concentration.

  When the total organic carbon concentration of the cleaning water in the primary treatment tank 3 rises, the transfer flow rate control device 37 opens the automatic control valve 26 and part of the cleaning water in the primary treatment tank 3 is transferred to the secondary treatment tank 4. Send it out. When cleaning water is introduced into the secondary processing tank 4 from the primary processing tank 3, the same amount of cleaning water is led out to the primary processing tank 3 through the return channel. Since the washing water returned from the secondary treatment tank 4 has a low total organic carbon concentration, the washing water in the primary treatment tank 3 can be diluted, and the washing water can take in organic compounds from the exhaust gas in the scrubber vessel 2. Maintain total organic carbon concentration.

  The secondary treatment tank 4 adsorbs the organic compound with the activated carbon 31 and decomposes the organic compound with microorganisms activated by the micro / nano bubbles introduced by the micro / nano bubble generator 32. In the secondary treatment tank 4, since the residence time of the washing water is longer than that in the primary treatment tank, the total organic carbon concentration of the stored washing water is sufficiently lower than the washing water in the primary treatment tank 3. Can be maintained.

  If the total organic carbon concentration of the washing water in the secondary treatment tank is sufficiently low, the total organic carbon concentration of the washing water in the primary treatment tank 3 is low if the operation of the micro / nano bubble generator 32 is stopped. In this case, since cleaning water is not transferred from the primary treatment tank 3 to the secondary treatment tank 4, the operation of the micro / nano bubble generating device 32 is suspended, and energy consumption can be suppressed.

  On the contrary, when the concentration of the organic compound in the exhaust gas is extremely high, the total organic carbon concentration of the cleaning water in the primary treatment tank 3 becomes high, and the amount of the organic compound transferred to the secondary treatment tank 4 also increases. When the total organic carbon concentration in the secondary treatment tank 4 increases, the return flow rate control means 38 throttles the opening of the automatic control valve 27 and returns the cleaning water returned to the primary treatment tank 3 via the return flow path 24. Reduce the flow rate. As a result, in the secondary treatment tank 4, the wash water overflows from the water distribution pipe 34, and in the primary treatment tank 3, makeup water is replenished from the water supply line (not shown) so as to keep the amount of wash water constant. The wash water stored as is diluted.

  In this way, the total organic carbon concentration of the wash water stored in the primary treatment tank 3 and circulated and sprayed to the packed bed 8 is kept below a predetermined concentration, so that the organic compounds in the exhaust gas are removed from the scrubber vessel 2. It can be removed by continuously dissolving in washing water without leaving.

  Furthermore, FIG. 2 shows an exhaust gas treatment apparatus 1 of a second embodiment of the present invention. In the following description, the same reference numerals are given to the components described above, and description thereof is omitted. In the exhaust gas treatment apparatus 1 of this embodiment, a porous plate 39 is installed on the packed bed 8, and the activated carbon 40 is arranged on the porous plate 39.

  Microorganisms in the washing water adhere to the surface of the activated carbon 40 and propagate. The microorganisms propagated on the activated carbon 40 are activated by being supplied with abundant oxygen, and are collected in the primary treatment tank 3 together with the washing water, and the activity of the microorganisms propagated on the activated carbon 18 held in the storage unit 17 is observed. There is an action to further improve. It is also possible to decompose volatile organic compounds in the exhaust gas in situ.

  FIG. 3 shows an exhaust gas treatment apparatus 1 according to a third embodiment of the present invention. In the exhaust gas treatment apparatus 1 of the present embodiment, an ozone generator 41 is connected to the suction side of the blower 36 of the micro / nano bubble generator 32 of the secondary treatment tank 4.

  Thereby, the micro / nano bubble generating device 32 generates ozone micro / nano bubbles including ozone. Since ozone has a high oxidizing power, the ozone micro-nano bubbles not only activate microorganisms and are used for the decomposition of organic compounds, but also directly oxidize and decompose the contacted organic compounds.

  As in the fourth embodiment of the present invention shown in FIG. 4, activated carbon 40 is arranged in the primary treatment tank 3 in the scrubber container 3 of the exhaust gas treatment device 1 of the third embodiment, as in the second embodiment. The decomposition of organic compounds can also be promoted.

  FIG. 5 shows an exhaust gas treatment apparatus 1 according to a fifth embodiment of the present invention. The exhaust gas treatment apparatus 1 of the present embodiment is provided with a self-supplied micro / nano bubble generation apparatus 42 in the secondary treatment tank 4 in place of the forced intake type micro / nano bubble generation apparatus 32 in the exhaust gas treatment apparatus of the first embodiment. It is. The micro / nano bubble generating device 42 sucks out the cleaning water in the primary treatment tank 4 by the circulation pump 43, injects it into the micro bubble generator 44, and shears the self-supplied air through the control valve 45 by the flow rate of the cleaning water. By doing so, micro-nano bubbles are generated and discharged together with cleaning water. Also in this embodiment, the microorganisms in the secondary treatment tank 4 can be activated with micro / nano bubbles to decompose organic compounds in the wash water.

  Further, as in the sixth embodiment of the present invention shown in FIG. 6, an ozone generator 41 is connected to the intake pipe of the micro / nano bubble generator 42 of the fifth embodiment so that the organic compound can be oxidatively decomposed. Good.

Using the exhaust gas treatment apparatus 1 according to the first embodiment of the present invention shown in FIG. 1, a verification test for treating exhaust gas from an actual semiconductor factory was conducted. Exhaust gas treatment apparatus 1 using the Test, the capacity of the scrubber vessel 2 is 2m ^3, the capacity of the primary treatment tank 3 and the secondary treatment tank 4 was 1 m ³ together.

  After accommodating the new activated carbon 18 and the activated carbon 31 in the storage chamber 17 of the primary treatment tank 3 and the storage chamber 30 of the secondary treatment tank 4, respectively, An operation of continuously treating exhaust gas containing isopropyl alcohol at a semiconductor factory was performed.

  As a result of measuring the removal rate of isopropyl alcohol after 7 days from the start of the treatment of exhaust gas, a satisfactory result of 94% was obtained.

  Furthermore, as a result of measuring the concentration of acetone generated by collecting washing water and firstly decomposing the removed isopropyl alcohol, the concentration was 18% of the amount converted from the removed isopropyl alcohol. That is, it was confirmed that acetone produced by the primary decomposition of isopropyl alcohol was further decomposed and rendered harmless.

1 is a schematic view of a wastewater treatment apparatus according to a first embodiment of the present invention. Schematic of the waste water treatment apparatus of 2nd Embodiment of this invention. Schematic of the waste water treatment apparatus of 3rd Embodiment of this invention. Schematic of the waste water treatment apparatus of 4th Embodiment of this invention. Schematic of the waste water treatment apparatus of 5th Embodiment of this invention. Schematic of the waste water treatment apparatus of 6th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust gas processing apparatus 2 Scrubber container 3 Primary processing tank 4 Secondary processing tank 9 Sprinkling means 12 Circulating flow path 13 Sprinkling pump 14 Micro nano bubble generator 18 Activated carbon 19 TOC measuring instrument 23 Transfer flow path 24 Return flow path 25 Automatic control valve 26 Automatic Control Valve 27 Automatic Control Valve 28 Activated Carbon 32 Micro / Nano Bubble Generator 33 TOC Measuring Device 35 Pump Type Micro / Nano Bubble Generator 37 Transfer Flow Control Unit 38 Return Flow Control Unit 42 Micro Nano Bubble Generator

Claims (11)

Store cleaning water containing microorganisms in the primary treatment tank,
Circulating and spraying the cleaning water to the exhaust gas, so that the organic compound in the exhaust gas is dissolved in the cleaning water,
Introducing micro-nano bubbles into the primary treatment tank, activating the microorganisms and decomposing the organic compounds in the wash water;
Introducing the washing water of the primary treatment tank into the secondary treatment tank,
Introducing micro-nano bubbles into the secondary treatment tank, activating the microorganism, further decomposing the organic compound and its decomposition product in the wash water, and then returning the wash water to the primary treatment tank. A featured exhaust gas treatment method. A scrubber vessel provided with watering means through which exhaust gas is inserted, circulating cleaning water containing microorganisms into the exhaust gas, and dissolving the organic compound in the exhaust gas into the cleaning water;
A first micro / nano bubble generating device that is integrally formed under the scrubber container, stores the cleaning water, and introduces micro / nano bubbles into the stored cleaning water, and decomposes the organic compound by the microorganism 1 The next treatment tank,
A secondary treatment tank for storing the washing water derived from the primary treatment tank and further decomposing the remaining organic compound and a decomposition product thereof by the microorganism and then returning it to the primary treatment tank. An exhaust gas treatment apparatus characterized by.   The exhaust gas treatment apparatus according to claim 2, wherein the primary treatment tank holds activated carbon in the washing water to be stored.   The exhaust gas treatment apparatus according to claim 2 or 3, wherein the second treatment tank holds activated carbon in the washing water to be stored.   The exhaust gas treatment apparatus according to any one of claims 2 to 4, wherein the secondary treatment tank includes a second micro / nano bubble generation device that introduces micro / nano bubbles into the stored wash water.   The exhaust gas treatment apparatus according to claim 5, wherein the second micro / nano bubble generator includes a submerged pump type micro nano bubble generator. The primary treatment tank includes a first TOC measuring device that measures the total organic carbon concentration of the washing water to be stored,
Furthermore, it has a transfer flow rate control means for adjusting the flow rate of the washing water transferred from the primary treatment tank to the secondary treatment tank according to the total organic carbon concentration measured by the first TOC measuring device. The exhaust gas treatment apparatus according to any one of claims 2 to 6, characterized in that   The said transfer flow rate control means is a means to adjust the opening degree of the automatic control valve provided in the transfer flow path which transfers the said wash water from the said primary treatment tank to the said secondary treatment tank. The exhaust gas treatment apparatus according to 7. The secondary treatment tank includes a second TOC measuring device that measures the total organic carbon concentration of the washing water to be stored,
3. A return flow rate control means for adjusting a flow rate of the washing water to be returned to the primary treatment tank according to the total organic carbon concentration measured by the second TOC measuring device. To 8. The exhaust gas treatment apparatus according to any one of 1 to 8.   The return flow rate control means is means for adjusting an opening of an automatic adjustment valve provided in a return flow path for returning the washing water from the secondary treatment tank to the primary treatment tank. The exhaust gas treatment apparatus according to 9.   The exhaust gas treatment apparatus according to any one of claims 2 to 10, wherein the organic compound contained in the exhaust gas contains a volatile organic compound.

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