JP2006239516A - Absorption liquid composition for removal of volatile organic solvent and process for removal of volatile organic solvent using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a removing method for removing VOC in an absorption liquid or a treatment gas in order to absorb and recover VOC in a large amount of air flow of the treatment liquid in the industry for treating the large amount of a volatile organic solvent (VOC). <P>SOLUTION: The absorption liquid composition of the volatile organic solvent in the treatment liquid is comprised of (a) water and (b) (i) 0.01-5 wt% of at least one of surfactants selected from the group consisting of a non-ionic surfactant and an ionic surfactant and (ii) 0.0001-5 wt% of a frothing adjusting agent. The removing method of VOC in the treatment liquid is characterized by bringing the VOC containing treatment liquid into contact with the absorption liquid composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an absorbent composition for removing volatile organic solvents (hereinafter referred to as “VOC”) in process gases discharged from various factories, and a volatile organic solvent using the absorbent composition. It relates to the removal method, and more specifically, aroma such as toluene contained in the exhaust gas of the laboratory, laboratory of printing, painting, textile industry, wood product manufacturing industry, adhesive-related industry, film processing industry, chemical industry, etc. The present invention relates to an absorbent composition for removing VOCs in the air contaminated by VOCs typified by solvent gases such as group hydrocarbons, ethyl acetate, and ketones, and a removal method using the same.

  Process gases discharged from factories such as painting, printing or textile factories include aromatic hydrocarbons such as aromatic hydrocarbons such as toluene, dimethylformamide (hereinafter referred to as "DMF"), methyl ethyl ketone (hereinafter referred to as VOCs such as “MEK”), ethyl acetate, isopropyl alcohol (hereinafter referred to as “IPA”) are included, and their removal and recovery are indispensable problems to be solved in terms of environmental conservation.

  Various methods for removing these VOCs including toluene have been proposed and practiced, and the following five types can be mentioned as typical ones.

The first method is a combustion method, and is widely used. Combustion methods include a direct combustion method and a catalytic combustion method, both of which oxidatively decompose VOC in a high temperature field. However, there is a problem that dioxins may be generated depending on temperature conditions, CO ₂ is generated by combustion, and in the case of VOC containing chlorine, it is necessary to remove hydrogen chloride generated by combustion. In addition, the high running cost is a drawback. In addition, since the apparatus is enlarged, it is difficult to adapt to the processing of a small amount of VOC discharged from a small factory.

  The second method is a photocatalytic method. Although there is an advantage that VOC can be processed at a low temperature by a catalytic action such as titanium oxide, a large amount of ultraviolet rays is required for removing VOC, and there is a problem that the processing speed is slow. Further, when a catalyst deterioration substance is mixed in the processing air, it is necessary to take measures such as installing a pretreatment device.

  The third method is a cooling / aggregation method in which exhaust gas is cooled or compressed / cooled to condense and recover VOCs. Compared to the combustion method, there are fewer problems of generating harmful substances, but there is a problem that it is limited to high concentrations and low airflow.

  The fourth method is an adsorption method, and a physical adsorption method is particularly widespread. The physical adsorption method is a method in which treated air is mainly brought into contact with an adsorbent such as activated carbon or zeolite to adsorb VOC contained therein. This method has the advantage that the adsorbed VOC can be desorbed and recovered by heating with vapor after adsorption, but the adsorbent pores are immediately saturated or the substance once adsorbed is re-released. There were problems such as. On the other hand, as a chemical adsorption method, a method is known in which treated air is passed through a cyclodextrin aqueous solution and VOC is incorporated as an inclusion compound by hydrogen bonding into a cavity formed by the cyclic structure of cyclodextrin to remove it.

  The fifth method is a liquid absorption method, which is an absorption method using an organic liquid of an organic material typified by a high boiling point solvent such as kerosene. In addition to kerosene, glycol monoalkyl ether and an olefin having 10 or more carbon atoms, For example, an absorption method using a mixture with decene as an absorption liquid has been proposed. In the absorption method using an organic liquid, a high boiling point solvent that has absorbed VOC can be used as a fuel, and the absorbed VOC can be recovered and reused. However, in the conventional processing apparatus using this method, it is difficult to efficiently contact the processing air with the solvent, there is a problem that the processing efficiency is not high, and the high boiling point solvent has a high viscosity, Washing with water is difficult, there is a problem of adhesion to equipment, and there is a difficulty in handling.

  Under such circumstances, a method of using an aqueous solution using a smaller amount of a surfactant has been proposed. For example, Prior Document 1 (Patent Document 1: Japanese Patent Laid-Open No. 10-151316) includes two or more surfactants having different HLBs so as to be compatible with various hydrophilic and hydrophobic odor substances. A method for removing VOCs, which are malodorous substances, using an aqueous solution is disclosed. As surfactants, polyethylene glycol monoether, EO adducts of higher alcohols, EO adducts of alkylphenols and the like are described.

In addition, Prior Art Document 2 (Patent Document 2; Japanese Patent Application Laid-Open No. 59-183815) describes a purification device for cleaning exhaust gas from a scrap preheating furnace device with alcohol and a surfactant solution.
Prior art 3 (Patent Document 3; Japanese Patent Application Laid-Open No. 2001-25900) describes a 1% by weight or less surfactant aqueous solution as a cleaning liquid for an air purifier for home appliances.
However, the VOC removal method disclosed by the prior art as described above is related to steel, petroleum-related products, air purification home appliances, and the like, and has a relatively small flow rate of discharged processing gas.

On the other hand, in each industry such as printing, painting, and fiber, the amount of processing gas VOC handled is large, and since the processing gas is diluted to a low concentration, VOC is removed from the processing gas with a large air volume. Is required.
However, if the surfactant aqueous solution treatment method is applied under the above-mentioned large air volume conditions, bubbles are generated significantly inside the absorption device, and the generated bubbles overflow outside the device, resulting in a situation where smooth operation of the device is impaired. In addition, it has been found that the VOC absorbed from the processing gas into the absorbing solution is discharged again together with bubbles to the outside.

In view of such circumstances, in the absorbent composition for VOC removal that can be used even under conditions where the treatment conditions are large, and the VOC removal method under such conditions, technical development that can solve the above problems and achieve highly efficient VOC removal Is anxious.
Japanese Patent Laid-Open No. 10-151316 JP 59-183815 A JP 2001-25900 A

  Accordingly, an object of the present invention is to provide an absorption liquid composition that can remove low-concentration VOCs contained in a large amount of processing gas such as processing gas discharged in each factory such as printing, painting, and fiber processing at a high removal rate. It is in the point which provides the thing, and also in the point which provides the removal method of VOC from the said process gas which uses this absorption liquid composition.

  In view of the development status of a method for removing VOC from a VOC-containing process gas, the present inventors have conducted various studies to solve the above-described problems. In order to remove water at a high removal rate, the use of a dilute aqueous solution of a specific surfactant and mixing of a foam control agent with the aqueous solution suppresses foaming appropriately, and an absorbent solution containing only a surfactant. It has been found that the removal rate of VOC is improved as compared with the above, and further, by mixing a dissolution accelerator, the problem of precipitation due to temperature change is solved and at the same time the removal rate of VOC is further improved. It was. Based on this knowledge, the present invention was conceived and completed.

Thus, according to the present invention,
In claim 1,
(A) water,
(B) 0.01 to 5% by weight of at least one surfactant selected from the group consisting of (i) a nonionic surfactant and an ionic surfactant contained in the water, and (ii) foaming Conditioner 0.0001 to 5% by weight
An absorbent composition for removing VOC in a process gas is provided.

  In addition, as a preferred embodiment of the invention according to claim 1 of the present application, an absorbing liquid composition for removing VOC in a processing gas according to claims 2 to 7 shown below is provided.

That is,
(1) According to claim 2,
An absorption liquid composition for removing the VOC in which a dissolution accelerator is mixed in an amount of 0.3 times or more with respect to the surfactant 1 is provided.

(2) According to claim 3,
The VOC removal absorbent composition, wherein the nonionic surfactant is at least one compound selected from the group consisting of the following (x) and (y): (x) higher alcohols, alkylphenols, higher fatty acids, A polyalkylene glycol type nonionic surfactant which is an alkylene oxide adduct of a higher aliphatic amine and a fatty acid amide.
(Y) Polyhydric alcohol type nonionic surfactants which are esters of glycerin, pentaerythritol, sorbit, sorbitan, monoalkanolamine or dialkanolamine and fatty acids and their adducts with alkylene oxide.
Is provided.

式中、Ｒ¹は、
（１）炭素数８以上の直鎖状または分岐状アルキル基、または
（２）炭素数８以上の直鎖状または分岐状アルキル基で置換した
フェニル基、または
（３）Ｒ^４ＣＯ基（ただし、Ｒ^４は炭素数８以上の直鎖状または分
岐状アルキル基である。）、
ｎは、平均５以上の整数である。
で表されるポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルフェニルエーテルまたはポリオキシエチレン脂肪酸エステルである前記ＶＯＣの除去用吸収液組成物
が提供される。 (3) According to claim 4,
The nonionic surfactant is represented by the general formula (1)

Where R ¹ is
(1) a linear or branched alkyl group having 8 or more carbon atoms, or
(2) Substituted with a linear or branched alkyl group having 8 or more carbon atoms
A phenyl group, or
(3) R ⁴ CO group (where R ⁴ is a linear or branched group having 8 or more carbon atoms)
It is a branched alkyl group. ),
n is an integer of 5 or more on average.
The VOC removal absorbent composition is a polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether or polyoxyethylene fatty acid ester represented by the formula:

(4) According to claim 5,
Provided is an absorbent composition for removing the VOC, wherein the ionic surfactant is at least one anionic surfactant selected from the group consisting of fatty acid, alkylated sulfuric acid and alkali metal salt of alkylated sulfonic acid. Is done.

(5) According to claim 6,
There is provided an absorbent composition for removing the VOC, wherein the foam control agent is at least one compound selected from the group consisting of silicone-based, pluronic ^(R) -type alkylene oxide adducts, and polypropylene glycol-based.

(6) According to claim 7,
Absorption for removing the VOC, wherein the solvent accelerator is at least one oxygen-containing water-soluble compound selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, other polyglycols, aliphatic alcohols and water-soluble ketones. A liquid composition is provided.

Moreover, according to the present invention,
In Claim 8, It is an absorption liquid composition for dilution for preparing the absorption liquid composition for removal of the volatile organic solvent in process gas, Comprising: (a) It consists of a nonionic surfactant and an ionic surfactant. For 100 parts of at least one surfactant selected from the group, (b) 5-20 parts of a foam control agent, (c) 50-200 parts of a dissolution accelerator, and (d) 50-500 parts of water. An absorbent composition for dilution is provided.

further,
In Claim 9, The processing gas containing a volatile organic solvent is made to contact with the absorption liquid composition of Claim 1, The method of removing this VOC from the processing gas characterized by the above-mentioned is provided.

According to the absorbent composition for removing VOC in the processing gas according to the invention of claim 1, in the industry that handles a large amount of VOC by coexisting the specific surfactant and the foam control agent, It is possible to easily remove low-concentration VOCs in a large amount of processing gas.
Moreover, the generation | occurrence | production of the excessive bubble resulting from the process gas of large air volume is suppressed, a foaming level is adjusted, and the removal efficiency of VOC is high and there exists a remarkable effect.

  Furthermore, according to the absorbent composition for removing VOC of the invention according to claim 2, by further coexisting a dissolution accelerator in the surfactant and the foam regulator, in the preparation stage of the absorbent composition. It is possible to provide an absorbent composition that eliminates the influence of changes in environmental temperature and the like and prevents precipitation troubles such as solidification precipitation, and has a remarkable effect in removing VOC.

  Further, according to the absorbent composition for dilution according to the invention of claim 8, a concentrated liquid obtained by adding a dissolution accelerator or other oxygen-containing compound and water to the surfactant is provided for dilution. In addition to the simple operation of measuring and adding the absorbent, it is possible to provide an absorbent composition that solves problems such as solidification precipitation and is stable in quality and easy to handle.

The VOC removal method according to the invention of claim 9 uses the absorbent composition according to claim 1, and the flow rate of the processing gas containing VOC is 300 m with respect to 1 m ^{3 of the} absorbent composition at ambient temperature. Foaming is controlled even at a level of ³ / mm, and excellent removal efficiency for VOC can be achieved.

  Since such an effect is obtained, according to the present invention, compared with the combustion method, adsorption method and the like, it can be widely applied from a small-scale to a large-scale device, the installation area can be small, Further effects such as low cost can be obtained.

  The processing gas applicable to the absorbent composition for removing VOC of the present invention includes aromatic hydrocarbons such as toluene, amides such as dimethylformamide, ketones such as methyl etone ketone, alcohols such as isopropyl alcohol, It contains one or more VOCs such as esters such as ethyl acetate, and is a processing gas generated from manufacturing processes in various industries as described above. Specifically, VOC is contained in a wide range of 10 to 5000 ppm. Is. According to the present invention, any kind of processing gas can be applied with regard to the content and content, but in particular, the amount of VOC generated in each industry such as printing, coating, and fiber is large, and the VOC has a low concentration. A diluted process gas is suitable.

The absorbent composition for removing VOC in the process gas according to the present invention is:
(A) water,
(B) 0.01-5% by weight of at least one surfactant selected from the group consisting of (i) a nonionic surfactant and an ionic surfactant contained in the water, (ii) a foam control agent 0.001 to 5% by weight
It consists of

Here, as the nonionic surfactant,
Examples include (X) polyalkylene glycol type nonionic surfactants and (Y) polyhydric alcohol type nonionic surfactants.

As a specific example of the surfactant belonging to the former polyalkylene glycol type nonionic surfactant,
Higher alcohol,
Alkylphenols,
Higher fatty acids and alkylene oxide adducts of higher aliphatic amines can be used.

The higher alcohol is preferably a linear or branched saturated or unsaturated alkanol having 8 or more carbon atoms, particularly an aliphatic alkanol having 10 to 20 carbon atoms. Specifically, octanol (capryl), nonanol (nonyl), decanol (capryl), undecanol, dodecanol (lauryl), tridecanol, tetradecanol (myristyl), pentadecanol, hexadecanol (cetyl), heptadecanol , Octadecanol (stearyl), nonadecanol, icosanol (arakinyl) and the isomers thereof.
In addition, the alkyl group in the higher alcohol usually has a molecular weight distribution as a synthetic product.

  As the alkylphenol, the alkyl group is preferably a linear or branched alkyl group having 8 or more carbon atoms, like the alkyl group belonging to the higher alcohol, and in particular, an alkyl group having 10 or more carbon atoms is preferable. .

  Therefore, specific examples of preferred alkylphenols include octylphenol, nonylphenol, decylphenol, undecylphenol, dodecylphenol, tridecylphenol, tetradecylphenol, pentadecylphenol, hexadecylphenol, and the isomers thereof.

  The higher fatty acid is preferably a linear or branched fatty acid having 9 or more carbon atoms, and the alkyl group belonging to the fatty acid is preferably one having 8 or more carbon atoms, particularly 10 or more carbon atoms.

  Specifically, octanoic acid (caprylic acid), nonanoic acid (pelargonic acid), decanoic acid (capric acid), undecanoic acid, dodecanoic acid (lauric acid), tridecanoic acid (tridecylic acid), tetradecanoic acid (myristic acid), Pentadecanoic acid (pentadecylic acid), hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), octadecanoic acid (stearic acid), nonadecanoic acid (nonadecylic acid), icosanoic acid (arachidic acid), heicosanoic acid and the isomers thereof Examples thereof include branched alkanoic acids.

Examples of the higher aliphatic amine include primary amines having 8 or more carbon atoms (general formula: RNH ₂ ), secondary amines (general formula: R ₂ NH), or tertiary amines (general formula: R ₃ N). Any of these can be mentioned. Particularly preferred are those having 10 or more carbon atoms, and more than 12 carbon atoms. Specifically, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, nonadecylamine, icosylamine, etc. Amine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, diundecylamine, didodecylamine, ditridecylamine, ditetradecylamine, dipentadecylamine, dihexadecylamine, diheptadecylamine, dioctylamine Secondary amines such as decylamine, trihexylamine, triheptylamine, trioctylamine, tridodecylamine, trihexadecylamine, triocdecylamine, N-methylhept Triethanolamine, N- methyl-octylamine, it is possible to use tertiary amines and isomers thereof, such as N- methyl-decyl amine.

Examples of the fatty acid amide include amides having 8 or more carbon atoms (general formula: RCONH ₂ ). In particular, fatty acid amides having 8 or more carbon atoms and further 10 or more carbon atoms are suitable. Specific examples include octaneamide, nonaneamide, decanamide, undecanamide, dodecanamide, tridecanamide, tetradecanamide, hexadecanamide, octadecanamide, icosanamide, and amides belonging to N-mesyl fatty acid amide. .

式中、Ｒ¹は、
（１）炭素数８以上の直鎖状または分岐状アルキル基、または
（２）炭素数８以上の直鎖状または分岐状アルキル基で置換した
フェニル基、または
（３）Ｒ^４ＣＯ基（ただし、Ｒ^４は炭素数８以上の直鎖状または分
岐状アルキル基である。）、
ｎは、平均５以上の整数である。 Thus, the alkylene oxide adduct suitable as the polyalkylene glycol type nonionic surfactant of the component (X) of the absorbent composition for removing volatile organic compounds in the processing gas according to the present invention has the following general formula ( 1)

Where R ¹ is
(1) a linear or branched alkyl group having 8 or more carbon atoms, or
(2) Substituted with a linear or branched alkyl group having 8 or more carbon atoms
A phenyl group, or
(3) R ⁴ CO group (where R ⁴ is a linear or branched group having 8 or more carbon atoms)
It is a branched alkyl group. ),
n is an integer of 5 or more on average.

  Among the compounds represented by the general formula (1), as representative examples of the first compound type, polyoxyethylene alkyl ether, as representative examples of the second compound type, polyoxyethylene octylphenyl ether, third As a representative example of the type of the compound, polyoxyethylene fatty acid ester can be mentioned, and the compounds of the first type and the second type are particularly suitable. A compound having an alkyl group with less than 8 carbon atoms does not have a sufficient surface-active effect, and since the formation of an emulsion with VOC is incomplete, VOC cannot be sufficiently removed from the processing gas. Even when the number of additions does not reach an average of 5 mol, the surface active action is not sufficient, and as a result, VOC removal cannot be sufficiently achieved.

  Therefore, the nonionic surfactant as a component of the absorbent composition of the present invention has an alkyl group having 8 or more carbon atoms, preferably 10 or more, and an average number of EO additions of 5 or more, preferably 8 or more. From the viewpoint of improving the removal efficiency for VOC.

Next, the polyhydric alcohol type nonionic surfactant of component (Y) is a polyhydric alcohol or an ester of ethanolamine and a higher fatty acid and their alkylene oxide adducts.
As polyhydric alcohol,
Glycerin,
Pentaerythritol,
Sorbit,
Sorbitan,
As ethanolamine,
Monoethanolamine,
Mention may be made of diethanolamine.

（式中ＥＯは、エチレンオキサイドを示す。）
で表される如きエチレンオキサイド付加物（多価アルコールエステル−エーテル混合型）が挙げられる。 Examples of reaction products of glycerin and higher fatty acids include fatty acid monoglycerides, and

(In the formula, EO represents ethylene oxide.)
An ethylene oxide adduct represented by the formula (polyhydric alcohol ester-ether mixed type).

で示す化合物を挙げることができる。 Pentaerythritol also includes esters with higher fatty acids and ethylene oxide adducts, for example:

The compound shown by can be mentioned.

Examples of the ester and alkylene oxide adduct of sorbitan and the higher fatty acid include compounds represented by the following formulas.

  Furthermore, the ionic surfactant which is a component of the absorbent composition according to the present invention is an anionic surfactant, and examples thereof include alkali metal salts of fatty acids, alkylated sulfuric acids and alkylated sulfonic acids. . Specifically, oleic acid sodium salt, oleylsulfonic acid sodium salt, and the like can be used.

  As described above in detail, the main component of the absorbent composition according to the present invention is a water-soluble nonionic surfactant. In particular, as described above, a preferred surfactant is polyoxyethylene (10 ) Lauryl ether or polyoxyethylene (10) octylphenyl ether.

  The content of the surfactant (b) (i) in the absorbent composition according to the present invention is 0.01 to 5% by weight, preferably 0.03 to 4% by weight, more preferably 0.05 to 1%. % By weight. If the content of the surfactant does not reach 0.01% by weight, the absorption capacity for VOC is not sufficient. On the other hand, if the content exceeds 5% by weight, the dispersion performance of the surfactant is saturated, Not only can it not be obtained, but it becomes difficult to handle due to an increase in liquid viscosity. In addition, environmental conservation problems such as an increase in waste due to an increase in the amount of surfactant are also caused.

  The second component of the absorbent composition for removing VOC in the process gas according to the present invention is a foam control agent, and the foaming power of the surfactant is at an appropriate level, that is, 1 to 3 cm from the liquid level. The height is controlled and maintained. By controlling the foaming level, the absorption effect due to the expansion of the surface area is improved, and the bubble blowing is controlled to prevent the discharge of VOC, so that the removal efficiency for VOC can be improved.

  In addition to silicone-based foaming modifiers, there are fatty acid ester-based and alcohol-based ones. Silicone-based agents include dimethylpolysiloxane, silicone paste, silicone emulsion, silicone-treated powder, organically modified polysiloxane, fluorine silicone, etc. Can be mentioned.

  Examples of fatty acid esters include butyl stearate, isoamyl stearate, distearyl succinate, ethylene glycol distearate, sorbitan monolaurate, and alcohols such as polyoxyalkylene glycol, di-t-acylphenoxyethanol, and 3-butanol. 2-ethylhexanol and the like can be used.

  The content of the foam control agent in the absorbent composition is 0.0001 to 0.01% by weight, preferably 0.0001 to 0.003% by weight in the case of silicone as an active ingredient. On the other hand, the content of the organic foam control agent is 0.01 to 5% by weight, preferably 0.05 to 2% by weight. By blending a specific amount of the foam control agent within the range of the content, the dispersion performance of the surfactant is improved, the foaming force is controlled, and the VOC removal efficiency is improved.

  If the content of the foam control agent does not reach the lower limit, the defoaming ability is low, bubbles are released from the outlet of the gas-liquid contact zone of the VOC absorber, and the bubbles are released into the air accompanying the release of the bubbles. There is a problem that the amount of VOC emission increases, and the effectiveness of VOC removal cannot be obtained.

  The third component of the absorbent composition according to the present invention is a dissolution accelerator. As the dissolution accelerator, oxygen-containing water-soluble compounds are suitable, and specific examples include alkylene glycol, dialkylene glycol, trialkylene glycol, other polyalkylene glycols, aliphatic alcohols, water-soluble ketones, and the like. be able to.

  Surfactants, especially nonionic surfactants, are often solidified by the temperature, and in winter, when they are poured into water at once, they may partially gel and solidify and precipitate. In order to eliminate the difficulty, it is intended to promote the dissolution of the surfactant in water, and according to the study by the present inventors, the coexistence with the surfactant improves the VOC removal efficiency. It was grasped for the first time.

  The content of the dissolution accelerator is 0.3 times the amount of surfactant 1, and preferably the same amount or more. However, even if it exceeds 5% by weight, the ability is saturated, and it is only saturated. In other words, the solution becomes highly viscous, causing problems in handling and increasing waste.

Furthermore, the absorbing composition for dilution according to the present invention will be described.
The diluent composition for dilution comprises (a) 100 parts of at least one surfactant selected from the group consisting of a nonionic surfactant and an ionic surfactant, and (b) a foam control agent 5-20. A so-called concentrated stock solution consisting of an absorbent composition for dilution, characterized in that it comprises 50 parts by weight of (c) a dissolution accelerator and 50-500 parts of (d) water. In use, an absorbent composition can be prepared by diluting with water to a predetermined concentration. Commercially available nonionic surfactants include solid and liquid ones, but many are liquid in the summer but solidify in the winter. In addition, even if it is liquid, particularly in the winter, there is a problem that when it is poured into water at one time, it partially gels or easily solidifies and precipitates.

Therefore, by preparing a stock solution in which polyethylene glycol or other oxygen-containing compound and water are added to a surfactant and dissolving it in a large amount of water, the above-described trouble of solidification precipitation can be avoided. The addition operation is also simplified.
According to the present invention, there is provided an absorbent composition for dilution that can solve the problem of solidification precipitation.

Next, a method for removing VOC in the process gas according to the present invention will be described.
According to the present invention,
A method of removing the VOC from the processing gas by bringing a processing gas containing VOC into contact with the following absorbing liquid composition in a gas-liquid contact zone,
The absorbent composition comprises the following components (a) and (b):
(A) 0.01 to 5% by weight of at least one surfactant selected from the group consisting of a nonionic surfactant and an ionic surfactant;
(B) 0.0001 to 5% by weight of a foam control agent
It is the aqueous solution formed by containing.

  The VOC removal method in the processing gas according to the present invention is to cause absorption of VOC into the absorbing liquid by the gas-liquid two-phase contact between the VOC-containing processing gas and the absorbing liquid composition. In the contacting step, Although various methods can be selected, it is preferable to adopt a liquid dispersion method. Specifically, the absorbing liquid is dispersed in the processing gas in the form of droplets or a liquid film.

More specifically, according to the present invention,
The treatment is performed by spraying the absorbing liquid composition on the porous screen layer provided in the gas-liquid contact zone, circulating the porous screen layer, and passing the VOC-containing processing gas through the porous screen layer. There is provided a VOC removal method comprising contacting a gas with the absorbent composition.

Hereinafter, embodiments of the VOC removal method according to the present invention will be described in detail.
FIG. 1 is a schematic diagram showing an example of an embodiment of a VOC removal method according to the present invention. As shown in the figure, the VOC removal method according to the present invention is performed mainly using a gas-liquid contact tower 2, a solvent recovery tank (not shown), and a suction device (not shown).

The gas-liquid contact tower 2 is provided with an absorption liquid spray nozzle 200 on the side surface, and the absorption liquid supplied to the spray nozzle 200 via the absorption liquid transfer line 10 is sprayed to form a fine particle 300. The atomized absorption liquid is supplied to the porous screen layer 100 installed inside the gas-liquid contact tower 2, flows as a liquid film on the porous screen layer or downward between the layers, and is stored in the lower part of the gas-liquid contact tower 2. Is done. When the absorbing liquid flows downward between the porous screen layer and the interlayer, the VOC-containing processing gas is supplied from the gas introduction line 1 into the gas-liquid contact tower 2. The VOC-containing process gas is introduced by a blower (not shown) provided in the gas introduction line 1, or a suction device is connected to the purified gas discharge line 30 and is sucked by the device and set to a predetermined air volume. Under conditions, the VOC-containing process gas is passed through the gas-liquid contact tower. Even under high air flow conditions, foaming of the absorbing liquid is controlled, and gas-liquid contact is performed smoothly. The VOC-containing processing gas comes into contact with the absorbing liquid on the porous screen layer 100 and passes through the liquid film while VOC is absorbed in the liquid. In this contact, VOC is absorbed from the VOC-containing gas into the absorption liquid, and an emulsion is formed. The absorption liquid containing the formed emulsion is stored in the lower part of the gas-liquid contact tower, and then transferred to the solvent recovery tank by transfer lines 20 and 40.
On the other hand, the absorbing solution that has absorbed VOC is transferred to the solvent recovery device via the transfer line 50.
In addition, the contents of the surfactant, the foam control agent and the liquefying agent are monitored, and the decrease is replenished.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the examples.
In addition, the absorber etc. used in the Example etc. and the toluene concentration measuring method are shown below.

Nonionic surfactants such as absorbents OPE (10): Polyoxyethylene (10) octylphenyl ether (reagent)
LE (10): Polyoxyethylene (10) lauryl ether
275-100 ")
LE (3): Polyoxyethylene (3) Lauryl ether
275-30 ")
Sodium oleate: Reagent Foam regulator Silicone: Water emulsion type silicone antifoam (KM73 manufactured by Shin-Etsu Chemical Co., Ltd.)
Use Organic defoamer: Sanyo Kasei Kogyo "Calaline DF" Toluene, MEK, Ethyl acetate: Reagents

Toluene concentration measurement method According to the gas detector tube method for toluene manufactured by Gastec Corporation.

Example 1-5
The surfactant and foam control agent shown in Table 1 are mixed with water in the proportions shown in the same table to prepare an absorption liquid. To 5 ml of the absorption liquid, 1.5 ml of toluene as a volatile solvent is mixed. The liquid separation performance by the shaker method was evaluated. The evaluation results are shown in Table 1.

[conditions]
Swing width 4.3mm
Liquid temperature 18 ℃
Frequency 46.3H
Test tube capacity 10ml
Test time 1 minute Solvent / Absorbent 1.5ml / 5ml

  According to the evaluation results, the aqueous solutions of the nonionic surfactant and the anionic surfactant were separated into two layers by forming an emulsion with the organic solvents toluene, ethyl acetate and the like, and allowing to stand for 10 minutes.

Example 6
Polyoxyethylene (10) lauryl ether (0.5% of LE (10)) as a nonionic surfactant and silicone (water emulsion type silicone antifoaming agent) (hereinafter referred to as “silicon emulsion”) as a foam control agent .) Was mixed with 0.05% water as an active ingredient to prepare a VOC absorption liquid having the following composition.

VOC absorption liquid polyoxyethylene (10) lauryl ether 0.5%
Silicone emulsion 0.05%
Water 99.45%
100.00%

When this VOC absorption liquid was used for the following VOC absorption performance evaluation, no bubble was blown out in Table 2, but a bubble layer of about 3 cm was formed on the liquid surface in the gas-liquid contact tower. Observed that. Although the toluene concentration at the inlet of the apparatus was 700 ppm, the toluene concentration at the outlet was reduced to 30 ppm. The evaluation results are summarized in Table 2 together with other examples and comparative examples.

Example 7
0.5% polyoxyethylene (10) lauryl ether (LE (10)) as a nonionic surfactant, 0.05% silicone emulsion as a foam control agent, and 1.0% polyethylene glycol as a dissolution accelerator It mixed with% water to prepare a VOC absorption solution.

VOC absorption liquid polyoxyethylene (10) lauryl ether 0.5%
Silicone emulsion 0.05%
Polyethylene glycol 1.0%
Water 98.45%
100.00%

In the same manner as in Example 1, the VOC absorption liquid was subjected to the following VOC absorption performance evaluation. Although no bubble was blown out, a bubble layer was present at the same level on the liquid surface. The toluene concentration at the inlet of the apparatus was 700 ppm, whereas it decreased to 20 ppm at the outlet.

Comparative Example 1
A VOC absorbing solution was prepared using only water, and the VOC absorbing performance was evaluated in the same manner as in Examples 1 and 2. Although no bubbles were blown out, the toluene concentration at the inlet of the apparatus was 700 ppm, and the outlet was only 400 ppm.

Comparative Example 2
Polyoxyethylene (10) lauryl ether (LE (10)) as a nonionic surfactant was dissolved in 0.5% water to prepare a VOC absorbing solution.

VOC absorption liquid polyoxyethylene (10) lauryl ether 0.5%
Water 99.5%
100.0%

The VOC absorption liquid was subjected to the following VOC absorption performance evaluation. Bubbles were blown out remarkably, the apparatus could not be operated smoothly, and the absorbing solution could not be used. The toluene concentration at the inlet of the apparatus was 700 ppm, whereas that at the outlet was 80 ppm.

Evaluation of VOC Absorption Performance VOC-containing air was introduced into the gas-liquid contact tower shown in FIG. 1, and an experiment was conducted to remove VOC from the treated air. Absorption liquid and absorption conditions are as follows.
The absorption conditions were controlled by connecting a suction device (“Kesmak” manufactured by Ricken Co., Ltd.) to the VOC absorber and adjusting the degree of suction according to the water flow velocity.

VOC component and concentration: Toluene 700ppm
Processing air temperature: 25 ° C
Processed air volume: 5.5m ³ / min
Processing air speed (outlet): 20m / Sec
Suction water volume: 85 liters (shower speed 40 l / min)
Aspirate fluid (absorbing fluid spraying speed): 65 liters (shower speed 20 l / min)
Absorbent composition: Each example Absorbent temperature: 25 ° C

In the test environment, VOC (toluene) was absorbed and removed from the treated air.

The present invention provides an absorbing liquid composition for removing a volatile organic solvent in a processing gas using a dilute aqueous solution of a surfactant, and a method for removing a volatile organic solvent using the absorbing liquid composition.
Therefore, the present invention is useful for various industries, particularly in the printing, painting, textile industry, wood product manufacturing industry, chemical industry, etc., which use a large amount of organic solvents, and in the treatment of exhaust gas with large air volume in the laboratory. From this aspect, the contribution to each industry is extremely large.

It is a part of process drawing which shows one Example of the VOC removal method which concerns on this invention.

Explanation of symbols

1 VOC-containing gas introduction line 2 Gas-liquid contact tower 10 Transfer line 20 Transfer line 30 Transfer line 40 Transfer line 50 Transfer line 100 Perforated screen 200 Spray nozzle 300 Absorbing liquid shower

Claims (9)

(A) water,
(B) 0.01 to 5% by weight of at least one surfactant selected from the group consisting of (i) a nonionic surfactant and an ionic surfactant contained in the water, and (ii) foaming Conditioner 0.0001 to 5% by weight
An absorbent composition for removing a volatile organic solvent in a processing gas.   The absorbent composition for removing a volatile organic solvent according to claim 1, further comprising a dissolution accelerator mixed in an amount of 0.3 times or more with respect to the surfactant. The absorbent composition for removing a volatile organic solvent according to claim 1, wherein the nonionic surfactant is at least one compound selected from the group consisting of the following (x) and (y).
(X) A polyalkylene glycol type nonionic surfactant which is an alkylene oxide adduct of higher alcohol, alkylphenol, higher fatty acid, higher aliphatic amine and fatty acid amide.
(Y) Polyhydric alcohol type nonionic surfactants which are esters of glycerin, pentaerythritol, sorbit, sorbitan, monoalkanolamine or dialkanolamine and fatty acids and their adducts with alkylene oxide. The nonionic surfactant is represented by the general formula (1)

Where R ¹ is
(1) a linear or branched alkyl group having 8 or more carbon atoms, or
(2) Substituted with a linear or branched alkyl group having 8 or more carbon atoms
A phenyl group, or
(3) R ⁴ CO group (where R ⁴ is a linear or branched group having 8 or more carbon atoms)
It is a branched alkyl group. ),
n is an integer of 5 or more on average.
The absorbent composition for removing a volatile organic solvent according to claim 1, which is a polyoxyethylene alkyl ether, a polyoxyethylene alkyl phenyl ether or a polyoxyethylene fatty acid ester represented by the formula:   2. The volatile organic solvent according to claim 1, wherein the ionic surfactant is at least one anionic surfactant selected from the group consisting of fatty acid, alkylated sulfuric acid and alkali metal salt of alkylated sulfonic acid. Absorption liquid composition for removal. The absorption for removing a volatile organic solvent according to claim 1, wherein the foam control agent is at least one compound selected from the group consisting of silicone-based, pluronic ^(R) -type alkylene oxide adducts, and polypropylene glycol-based. Liquid composition.   The solvent accelerator is at least one oxygen-containing water-soluble compound selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, other polyglycols, aliphatic alcohols and water-soluble ketones. Absorbent composition for removing volatile organic solvents.   A dilute absorbent composition for preparing an absorbent composition for removal of volatile organic solvents in a process gas, wherein the absorbent composition is selected from the group consisting of (a) a nonionic surfactant and an ionic surfactant Characterized in that it comprises (b) 5-20 parts of a foam control agent, (c) 50-200 parts of a dissolution accelerator, and (d) 50-500 parts of water. An absorbent composition for dilution.   A method for removing a volatile organic solvent from a processing gas, comprising bringing a processing gas containing a volatile organic solvent into contact with the absorbent composition according to claim 1.

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