Exhaust gas deodorizer and exhaust gas deodorizing method

Abstract

To provide a technique that can effectively deodorize a malodor caused by a polycyclic aromatic compound in exhaust.SOLUTION: A deodorant is used for exhaust containing a polycyclic aromatic compound, wherein the deodorant is in the form of aqueous liquid and contains a nonionic surfactant with an HLB value of 4-10 by Griffin method. A method for deodorizing exhaust includes bringing exhaust containing a polycyclic aromatic compound into contact with the deodorant for exhaust.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a deodorizer for exhaust gas and a method for deodorizing exhaust gas. [Background technology]

[0002] Exhaust gases containing polycyclic aromatic hydrocarbons (PAHs) that can be generated from various factories, businesses, incineration facilities, etc. have a distinctive odor caused by the polycyclic aromatic hydrocarbons. This odor can cause problems in various factories, businesses, treatment facilities, etc. Therefore, various technologies for removing polycyclic aromatic hydrocarbons have been proposed.

[0003] For example, Patent Document 1 proposes an exhaust gas treatment method in which exhaust gas containing polycyclic aromatic hydrocarbons is passed through a PAHs decomposition catalyst body made of a porous ceramic filter carrying a PAHs decomposition catalyst, thereby removing dust from the exhaust gas and decomposing the PAHs. Also, Patent Document 2 proposes a method for removing polycyclic aromatic hydrocarbons in which polycyclic aromatic hydrocarbons generated by the combustion of organic substances are adsorbed by amorphous iron hydroxide and / or activated carbon.

[0004] On the other hand, for the purpose of deodorizing volatile organic compounds in exhaust gases, Patent Document 3 proposes a deodorizing composition for volatile organic compounds, which contains at least one anionic surfactant in an aqueous medium, and the anionic surfactant is present at a concentration equal to or higher than its critical micelle concentration. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-265930 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-020278 [Patent Document 3] Japanese Patent Application Publication No. 2017-221488 Summary of the Invention [Problem to be solved by the invention]

[0006] In the technology using a PAHs decomposition catalyst as disclosed in Patent Document 1 and the technology using an adsorbent as disclosed in Patent Document 2, it is necessary to ensure safety during catalyst decomposition and adsorbent cleaning, the installation area of ​​the reaction tower, etc. Therefore, there are many issues that need to be resolved before actually putting these technologies into practice, making them difficult to put into practice.

[0007] Furthermore, Patent Document 3 proposes a technology that enables the deodorization of volatile organic compounds in exhaust gases, but there is no knowledge about a technology for deodorizing polycyclic aromatic hydrocarbons in exhaust gases.

[0008] Therefore, the present invention aims to provide a technology that can effectively eliminate odors caused by polycyclic aromatic compounds in exhaust gases. [Means for solving the problem]

[0009] That is, the present invention provides a deodorizer for exhaust gases containing polycyclic aromatic compounds, which is an aqueous liquid deodorizer for exhaust gases containing a nonionic surfactant having an HLB value of 4 to 10 as determined by the Griffin method.

[0010] The present invention also provides a method for deodorizing exhaust gases, which comprises contacting exhaust gases containing polycyclic aromatic compounds with the above-described exhaust gas deodorizer. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a technology that can effectively deodorize odors caused by polycyclic aromatic compounds in exhaust gases. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0013] The present inventors have conducted various studies with the aim of providing a technology that can effectively deodorize odors caused by polycyclic aromatic compounds in exhaust gases. As mentioned above, it appears that there has been little knowledge about deodorizing technology for odors caused by polycyclic aromatic compounds in exhaust gases. Therefore, the present inventors have conducted studies and experiments for each type of deodorizing mechanism that is thought to be effective in deodorizing odors caused by polycyclic aromatic compounds.

[0014] Specifically, the inventors investigated (1) the principle of utilizing polymer crosslinking, (2) the principle of utilizing π-π interactions between aromatic rings, (3) the principle of utilizing the inclusion action of inclusion compounds, and (4) the principle of utilizing surfactant micelles.

[0015] (1) The principle of utilizing polymer crosslinking is based on the idea that some polymers, particularly polymer flocculants, form a network structure by crosslinking polymers together, and that polycyclic aromatic compounds may be captured in this network. Based on this idea, the present inventors conducted experiments and studies using various polymer flocculants, as exemplified in Test Example 1A below.

[0016] (2) Regarding the principle of utilizing π-π interactions between aromatic rings, it is known that aromatic rings in organic compounds tend to be stabilized in a stacked arrangement due to dispersion forces (π-π interactions) acting between two aromatic rings, also known as stacking interactions. The principle of (2) above is based on the idea that deodorization can be expected by contacting exhaust gas containing polycyclic aromatic compounds with a compound having an aromatic ring through π-π interactions (stacking interactions) between the compound and the polycyclic aromatic compound. Based on this idea, the present inventors conducted experiments and studies using various lignosulfonates that are suspected to undergo π-π interactions, as exemplified in Test Example 1B below.

[0017] (3) The principle of utilizing the inclusion action of an inclusion compound is based on the idea that polycyclic aromatic compounds in exhaust gases can be enclosed within the molecules of an inclusion compound by the action of incorporating another compound into the molecule of the inclusion compound (inclusion action).Cyclodextrin has pores within its cyclic structure large enough to encapsulate other relatively small molecules, and is hydrophobic, so it is thought that it is easy to encapsulate hydrophobic polycyclic aromatic compounds.For this reason, the present inventors conducted experiments and studies using various cyclodextrins, as exemplified in Test Example 1C described below.

[0018] (4) Regarding the principle of utilizing surfactant micelles, micelles formed by surfactants have both hydrophobic groups, which exhibit hydrophobicity, and hydrophilic groups, which exhibit hydrophilicity. When a hydrophobic compound is present, the micelles surround the compound. The principle (4) above is based on the idea that a similar phenomenon may occur with polycyclic aromatic compounds. Based on this idea, the present inventors conducted experiments and studies using various surfactants, as exemplified in Test Example 1D below.

[0019] The inventors conducted the above-mentioned experiments and studies diligently. As a result, among the experiments and studies using surfactants aimed at the principle (4) above, they discovered that a technology using a specific surfactant can effectively deodorize odors caused by polycyclic aromatic compounds in exhaust gases. Specifically, this technology relates to a deodorizer for exhaust gases containing polycyclic aromatic compounds, which is an aqueous liquid exhaust gas deodorizer containing a nonionic surfactant having an HLB value of 4 to 10 according to the Griffin method. This technology also relates to a method for deodorizing exhaust gases, which includes contacting exhaust gases containing polycyclic aromatic compounds with the exhaust gas deodorizer. This technology was effective when a nonionic surfactant with an HLB value of 4 to 10 was used. Therefore, the deodorizing mechanism is thought to be different from the principle (4) above, and involves the removal of polycyclic aromatic compounds from the gas phase through the formation of highly hydrophobic micelles.

[0020] Below, preferred configurations and the like of an "exhaust gas deodorizer" (hereinafter sometimes simply referred to as "deodorizer") and a "method for deodorizing exhaust gas" (hereinafter sometimes simply referred to as "deodorizing method") according to one embodiment of the present invention will be described from the perspective of the object of the present invention.

[0021] In this technology, the term "polycyclic aromatic compounds" refers to organic compounds containing two or more rings, including an aromatic ring, in one molecule. Polycyclic aromatic compounds typically include polycyclic aromatic hydrocarbons (PAHs; also known as fused-ring hydrocarbons), which are hydrocarbons formed by condensing aromatic rings without heteroatoms or substituents. Other examples of polycyclic aromatic compounds include those containing a substituent in a polycyclic aromatic hydrocarbon (substituted fused-ring compounds), those containing a heteroatom in a ring (heteropolycyclic aromatic compounds), those in which two or more rings containing an aromatic ring are condensed, and those in which two or more rings containing an aromatic ring are linked (linked polycyclic aromatic compounds), as well as compounds that fall into a combination of these categories (e.g., those containing the above-mentioned substituents and heteroatoms).

[0022] Examples of polycyclic aromatic compounds include azulene, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, sapotalin, indene, indane, benzofuran, benzothiophene, quinoline, biphenyl, acenaphthene, acenaphthylene, indole, fluorene, 1-naphthol, 2-naphthol, skatole, benzothiazole, benzoxazole, isoquinoline, and benzothiazolethiol.

[0023] The deodorizer of one embodiment of the present invention can be used for exhaust gases containing one or more of the above-mentioned polycyclic aromatic compounds. Furthermore, the deodorizing method of one embodiment of the present invention can be used for exhaust gases containing one or more of the above-mentioned polycyclic aromatic compounds.

[0024] The deodorant is more effective in deodorizing polycyclic aromatic compounds such as naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, biphenyl, benzothiophene, quinoline, and acenaphthylene. Therefore, exhaust gases containing one or more of these compounds are more suitable for deodorizing. Among the polycyclic aromatic compounds, this deodorant is even more effective in deodorizing naphthalene. Therefore, exhaust gases containing at least naphthalene as a polycyclic aromatic compound are more suitable for deodorizing.

[0025] Exhaust gases containing the above-mentioned polycyclic aromatic compounds (particularly naphthalene) are thought to be generated from various factories, such as those in the asphalt manufacturing industry, coal tar distillation and product manufacturing industry, petroleum product manufacturing industry, coal manufacturing industry, pesticide manufacturing industry, and paint manufacturing industry. Examples of exhaust gases include gases produced by coal dry distillation and petroleum distillation, gases produced when burning coal or petroleum, and gases produced by fuel combustion at thermal power plants and waste treatment facilities.

[0026] The exhaust gas may contain compounds other than the polycyclic aromatic compounds described above. Typical compounds other than polycyclic aromatic compounds include, for example, monocyclic aromatic compounds, aldehydes, lower fatty acids, and organic sulfur compounds. Examples of monocyclic aromatic compounds include benzene, toluene, xylene, styrene, benzonitrile, triethylbenzene, ethylmethylbenzene, pyridine, dimethylpyridine, phenol, and cresol. Examples of aldehydes include acetaldehyde and propionaldehyde. Examples of lower fatty acids include propionic acid, butyric acid, and valeric acid. Examples of organic sulfur compounds include methanethiol, methylthiophene, allyl sulfide, and dimethyl sulfide. The deodorant of one embodiment of the present invention may have a deodorizing effect on odors caused by monocyclic aromatic compounds such as those described above, in addition to a deodorizing effect on odors caused by polycyclic aromatic compounds.

[0027] The deodorant contains, as an active ingredient, a nonionic surfactant with an HLB value of 4 to 10 according to the Griffin method (sometimes referred to simply as "nonionic surfactant" in this specification). By using a nonionic surfactant with an HLB value of 10 or less, it is possible to effectively deodorize odors caused by polycyclic aromatic compounds in exhaust gases. On the other hand, if the HLB value of the nonionic surfactant is less than 4, solid precipitation or phase separation may occur in an aqueous liquid deodorant. However, by using a nonionic surfactant with an HLB value of 4 or more, it is possible to obtain a uniform aqueous liquid. The HLB value represents the degree of affinity of a surfactant for water and oil (a water-insoluble organic compound) and is also referred to as the hydrophilic-lipophilic balance. The HLB value according to the Griffin method is calculated by dividing the sum of the formula weights of the hydrophilic moieties in the surfactant by the molecular weight of the surfactant.

[0028] Since the properties of a surfactant are determined to some extent by its HLB value, it is believed that nonionic surfactants exist in aqueous liquid deodorants in a dispersed or dissolved state, or in both states, and can form micelles in these states, mainly depending on their HLB value.

[0029] The HLB value of the nonionic surfactant is preferably 4 to 9, more preferably 5 to 9, and even more preferably 6 to 9, because this makes it possible to more effectively deodorize odors caused by polycyclic aromatic compounds in exhaust gases.

[0030] Examples of nonionic surfactants having an HLB value of 4 to 10 include polyethylene glycol fatty acid esters (also called polyoxyethylene fatty acid esters), such as polyethylene glycol monolaurate, polyethylene glycol monooleate, and polyethylene glycol dioleate; polyoxyethylene sorbitan fatty acid esters, such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan triisostearate; sorbitan fatty acid esters, such as sorbitan monolaurate, sorbitan monocaprylate, sorbitan monopalmitate, sorbitan monostearate, and sorbitan monooleate; and polyoxyethylene sorbitan tetraoleate. Examples of the polyoxyalkylene alkyl ethers include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene isodecyl ether, polyoxyethylene dioleyl ether, and polyoxyethylene distearyl ether, polyoxyethylene alkyl ethers such as polyoxypropylene butyl ether, polyoxypropylene 2-ethylhexyl ether, and polyoxypropylene stearyl ether, and polyoxyethylene-polyoxypropylene alkyl ethers, and polyoxyalkylene derivatives such as polyoxyethylene alkylene alkyl ethers, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzyl phenyl ether.

[0031] Among the above, the nonionic surfactant preferably comprises at least one selected from the group consisting of polyethylene glycol fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyalkylene alkyl ethers, and sorbitan fatty acid esters. Among these, the nonionic surfactant more preferably comprises at least one selected from the group consisting of polyethylene glycol fatty acid esters, polyoxyethylene hydrogenated castor oil, and polyoxyethylene alkyl ethers. The number of moles of EO (ethylene oxide) added (hereinafter sometimes referred to as "n") in the above polyethylene glycol fatty acid esters, polyoxyalkylene alkyl ethers, and polyoxyethylene alkyl ethers is preferably 2 to 20, more preferably 4 to 12, and even more preferably 6 to 10.

[0032] The deodorant can contain one or more of the above-mentioned nonionic surfactants having an HLB value of 4 to 10. If the deodorant contains multiple types of nonionic surfactants with different HLB values ​​in the range of 4 to 10, it is expected that a deodorant that is effective against various types of polycyclic aromatic compounds in exhaust gases can be obtained, depending on the nonionic surfactants with specific HLB values.

[0033] A deodorant according to one embodiment of the present invention is an aqueous liquid composition containing the nonionic surfactant having an HLB value of 4 to 10. In the present technology, "aqueous liquid" refers to a liquid containing at least water. Therefore, this deodorant contains at least a nonionic surfactant having an HLB value of 4 to 10 and water. The nonionic surfactant contained in the deodorant and the fragrance (described below) optionally contained in the deodorant are components that tend to be considered flammable liquids. However, by including water in the deodorant, the deodorant becomes less flammable, thereby enhancing safety. From this perspective, the content of water in the deodorant is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more, based on the total mass of the deodorant.

[0034] From the viewpoint of the distribution and versatility of the deodorant, the deodorant preferably has a relatively high concentration of nonionic surfactant and a relatively low concentration of water during distribution, and is preferably diluted with water during use. The content of nonionic surfactant in the deodorant during distribution is preferably 10 to 90 mass%, more preferably 20 to 80 mass%, and even more preferably 30 to 80 mass%, based on the total mass of the deodorant. In this case, the content of water in the deodorant during distribution is preferably 30 mass% or less, more preferably 20 mass% or less, and even more preferably 15 mass% or less, based on the total mass of the deodorant.

[0035] The deodorant described above is preferably diluted with water before being sprayed when used, and more preferably used in a manner in which the deodorant diluted with water (diluted deodorant) is sprayed into exhaust gas. The dilution ratio with water is preferably 10 to 10,000 times, more preferably 100 to 5,000 times, and even more preferably 100 to 1,000 times, by mass relative to the deodorant at the time of distribution. The content of the nonionic surfactant in the deodorant (diluted deodorant) at the time of use is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.1 to 1% by mass, based on the total mass of the deodorant (diluted deodorant) at the time of use. Furthermore, the content of water in the deodorant (diluted deodorant) at the time of use in this case is preferably 90% by mass or more, based on the total mass of the deodorant (diluted deodorant) at the time of use.

[0036] In each of the above-mentioned deodorants during distribution and use, when the content of nonionic surfactant and the content of water are within the above-mentioned preferred ranges, the remaining portion other than the nonionic surfactant and water can be one or more of the other components described below. The remaining portion preferably includes the fragrance, solvent, and separation inhibitor described below, and more preferably the fragrance, solvent, and separation inhibitor.

[0037] The viscosity, pH, and other properties of the deodorant of one embodiment of the present invention are not particularly limited. From the perspective of making the deodorant easy to use by spraying, etc., the viscosity of the deodorant at 25°C is preferably 500 mPa·s or less, more preferably 300 mPa·s or less, and even more preferably 100 mPa·s or less. In this specification, the viscosity of the deodorant is a value measured using a rotational viscometer at a temperature of 25°C and a rotation speed of 100 rpm. The viscosity values ​​in the test examples described below are values ​​measured under the above conditions using a "Digital B-type Viscometer BASE L" (product name) manufactured by Atago Co., Ltd. (lower measurement limit: 20 mPa·s, rotor: L1-3).

[0038] The pH of the deodorant at 25°C is preferably 5 to 9, and more preferably 6 to 8. In this specification, the pH of the deodorant is a value measured using a pH meter at 25°C. The pH values ​​in the test examples described below are values ​​measured at a temperature of 25°C using a product under the trade name "HM-7J" manufactured by DKK-TOA Corporation.

[0039] A deodorant according to one embodiment of the present invention may contain other components in addition to the nonionic surfactant and water. In one aspect, the deodorant preferably contains, for example, cyclodextrin as the other component. When the deodorant contains cyclodextrin in addition to the nonionic surfactant, the deodorant can be expected to have a deodorizing effect utilizing the inclusion action of the cyclodextrin in addition to the deodorizing effect of the nonionic surfactant. Furthermore, this effect can be expected to reduce the required amount of the nonionic surfactant with an HLB value of 4 to 10, which is an essential component of deodorants. This can also contribute to reducing the cost of the deodorant by reducing the content of the active ingredient. Examples of cyclodextrin include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and derivatives thereof, and one or more of these can be used.

[0040] In one embodiment, the deodorant preferably contains an aromatic alcohol as an additional component for the purpose of adjusting the viscosity and / or freezing point of the deodorant and for the purpose of suppressing separation of the fragrance when a fragrance is further contained. Examples of aromatic alcohols include 2-phenoxyethanol, benzyl alcohol, salicylic alcohol, anisyl alcohol, vanillyl alcohol, cinnamyl alcohol, benzhydryl alcohol, and phenethyl alcohol. One or more of these can be used. Among these, it is more preferable for the deodorant to further contain 2-phenoxyethanol, from the viewpoint of easily achieving the above-mentioned objectives of the aromatic alcohol, maintaining the deodorizing effect, and reducing the required amount of the nonionic surfactant, which is an essential component. By including 2-phenoxyethanol in the deodorant, the viscosity of the deodorant can also be reduced.

[0041] In one embodiment, the deodorant preferably contains a fragrance as another component for the purpose of alleviating odor. The fragrance has a fragrance and can have the effect of masking odors caused by polycyclic aromatic compounds in exhaust gases. Furthermore, by containing the fragrance in the deodorant, it is expected that the required amount of nonionic surfactant, which is an essential component, can be reduced.

[0042] The fragrance may be a natural fragrance such as plant essential oil, a synthetic fragrance, or a blended fragrance that is a mixture of two or more of these. Among these, blended fragrances are preferred. Blended fragrances may contain, in addition to fragrances (fragrance compounds such as natural fragrances and synthetic fragrances), one or more solvents such as water, ethyl alcohol, glycerin, propylene glycol, and dipropylene glycol.

[0043] The fragrances (fragrance compounds) that can be contained in the deodorant are not particularly limited. Examples of each compound include hydrocarbon terpenes such as α-pinene, β-pinene, and limonene; alcohols such as linalool, geraniol, nerol, citronellol, terpineol, phenethyl alcohol, and cis-3-hexenol; esters such as linalyl acetate, benzyl acetate, isobornyl acetate, and p-tert-butylcyclohexyl acetate; aldehydes such as citral, geranial, neral, and hexylcinnamaldehyde; lactones such as γ-decalactone, γ-undecalactone, and coumarin; ketones such as camphor, menthone, γ-methylionone, and damascenone; indole; plant essential oils (natural fragrances) such as orange essential oil, lemon essential oil, lime essential oil, eucalyptus essential oil, and mint essential oil; and the like.

[0044] When a deodorant contains a fragrance, it is more preferable that the deodorant contains at least one selected from the group consisting of 2-phenoxyethanol, ethanol, and acetonitrile in addition to the fragrance. In addition to these, the inventors conducted studies using dimethylformamide, dimethyl sulfoxide, limonene, propylene glycol, and 1,4-butanediol and found that the deodorant containing 2-phenoxyethanol, ethanol, or acetonitrile is less likely to separate when mixed with water, a nonionic surfactant, and a fragrance. Therefore, when a deodorant contains a fragrance, 2-phenoxyethanol, ethanol, and acetonitrile act as separation inhibitors to suppress separation of the fragrance in the deodorant. In particular, when a deodorant contains 5% or more water by mass to reduce flammability and increase safety, adding a fragrance also tends to cause separation. However, adding the above-mentioned specific separation inhibitor further helps to suppress separation. The separation inhibitor may be contained in the deodorant in the same manner as in the blended fragrance as a solvent for the fragrance described above, but it is preferable to further contain a separation inhibitor in the deodorant in addition to the solvent contained in the blended fragrance. Among the above separation inhibitors, 2-phenoxyethanol is more preferable from the viewpoints that it has a higher boiling point of 247°C than ethanol (boiling point 78°C) and acetonitrile (boiling point 82°C), is less likely to volatilize, and therefore has good storage stability and is suitable for long-term storage.

[0045] The content of fragrance in the deodorant during distribution is preferably 1 to 70% by mass, more preferably 1 to 40% by mass, and even more preferably 10 to 30% by mass, based on the total mass of the deodorant. Furthermore, the content of fragrance in the deodorant (diluted deodorant) during use is preferably 0.0001 to 7% by mass, more preferably 0.001 to 1% by mass, and even more preferably 0.002 to 0.2% by mass, based on the total mass of the deodorant. When a fragrance composition such as a blended fragrance is used as the fragrance, the above-mentioned fragrance content refers to the content calculated as fragrance (fragrance compound) in the fragrance composition.

[0046] The total content of the specific separation inhibitors in the deodorant during distribution is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, and even more preferably 20 to 50% by mass, based on the total mass of the deodorant. Also, the total content of the specific separation inhibitors in the deodorant (diluted deodorant) during use is preferably 0.0001 to 8% by mass, more preferably 0.001 to 1% by mass, and even more preferably 0.002 to 0.5% by mass, based on the total mass of the deodorant.

[0047] A deodorizing method according to one embodiment of the present invention includes contacting exhaust gas containing a polycyclic aromatic compound with the above-described exhaust gas deodorizer. The method for contacting the exhaust gas with the deodorizer is not particularly limited. For example, the exhaust gas can be contacted with the deodorizer using a wet scrubber or a spray device.

[0048] As the wet scrubber, for example, a type in which a pressurized cleaning liquid is sprayed into the flow of exhaust gas (pressurized water type), a type in which exhaust gas is passed through stored water (stored water type), a type in which the cleaning liquid is dispersed by a rotor and brought into contact with the exhaust gas (rotary type), etc. The exhaust gas can be brought into contact with the deodorizer by adding the deodorizer to the cleaning liquid or stored water in these wet scrubbers, or by using the deodorizer separately from the cleaning liquid or stored water in a manner similar to that of using the cleaning liquid and stored water.

[0049] The spray device can be a device configured to allow contact between a gas and a liquid. This spray device may be a device configured to spray a gas so that the sprayed gas can come into contact with a liquid, or a device configured to spray a liquid so that the sprayed liquid can come into contact with the gas. Preferably, a spray device configured to spray a liquid so that the sprayed liquid can come into contact with a gas can be used, and it is preferable to use this spray device to spray a deodorizer into exhaust gas and bring the exhaust gas into contact with the deodorizer. Examples of such spray devices include a power sprayer, a power diffuser, and a manual atomizer.

[0050] The use of a wet scrubber is advantageous in that it allows the use of a wet dust collector in an existing exhaust gas treatment facility where wet dust collection treatment of exhaust gas is performed. Furthermore, the use of a spray device allows the installation in an existing exhaust gas treatment facility without requiring major modifications to the existing spray device. From the viewpoint of ease of introduction into existing exhaust gas treatment facilities and of easily achieving a deodorizing effect on odors caused not only by polycyclic aromatic compounds but also by monocyclic aromatic compounds, the exhaust gas deodorizing method of one embodiment of the present invention preferably includes contacting the exhaust gas with the exhaust gas deodorizer using a wet scrubber that performs wet dust collection treatment on the exhaust gas or a spray device.

[0051] The amount of deodorant used is not particularly limited. It is preferable to appropriately determine the amount of deodorant to be used relative to the exhaust gas through preliminary experiments at a factory or other site where actual exhaust gas is generated. According to the results of experiments and studies by the present inventors, for example, the amount of deodorant to be used relative to 1 L of exhaust gas is preferably 0.01 to 2000 mg / L, more preferably 0.1 to 100 mg / L, and even more preferably 0.2 to 10 mg / L, converted into the amount of the active ingredient (such as a nonionic surfactant with an HLB value of 4 to 10) of the agent.

[0052] As described above in detail, the deodorizer of one embodiment of the present invention is a deodorizer for use on exhaust gases containing polycyclic aromatic compounds, and is an aqueous liquid deodorizer containing a nonionic surfactant having an HLB value according to the Griffin method of 4 to 10. Furthermore, the deodorizing method of one embodiment of the present invention includes contacting the deodorizer with exhaust gases. Therefore, the deodorizer and deodorizing method of one embodiment of the present invention can provide a technology that can effectively deodorize odors caused by polycyclic aromatic compounds in exhaust gases.

[0053] As described above, the present technology can have the following configurations. [1] A deodorizer for exhaust gas containing polycyclic aromatic compounds, which is an aqueous liquid deodorizer for exhaust gas containing a nonionic surfactant having an HLB value of 4 to 10 according to the Griffin method. [2] The exhaust gas deodorizer according to [1] above, wherein the nonionic surfactant comprises at least one selected from the group consisting of polyethylene glycol fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyalkylene alkyl ethers, and sorbitan fatty acid esters. [3] The exhaust gas deodorizer according to [1] or [2] above, wherein the nonionic surfactant comprises at least one selected from the group consisting of polyethylene glycol fatty acid esters, polyoxyethylene hydrogenated castor oil, and polyoxyethylene alkyl ethers. [4] The deodorizer for exhaust gas according to any one of the above [1] to [3], which contains a plurality of types of the nonionic surfactants having different HLB values. [5] The exhaust gas deodorizer according to any one of the above [1] to [4], further comprising cyclodextrin. [6] The deodorizer for exhaust gas according to any one of the above [1] to [5], further comprising 2-phenoxyethanol. [7] The exhaust gas deodorizer according to any one of [1] to [6] above, further comprising a fragrance and a separation inhibitor for inhibiting separation of the fragrance in the deodorizer, wherein the separation inhibitor is at least one selected from the group consisting of 2-phenoxyethanol, ethanol, and acetonitrile. [8] The deodorizer for exhaust gas according to any one of the above [1] to [7], which is diluted with water and then sprayed. [9] The deodorizer for exhaust gases according to any one of the above [1] to [8], which has a viscosity of 500 mPa·s or less at 25°C.

[10] The exhaust gas deodorizer according to any one of [1] to [9] above, wherein the polycyclic aromatic compound contains at least one selected from the group consisting of naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, biphenyl, benzothiophene, quinoline, and acenaphthylene.

[11] The deodorizer for exhaust gas according to any one of the above [1] to

[10] , wherein the polycyclic aromatic compound contains at least naphthalene.

[12] A method for deodorizing exhaust gas, comprising contacting exhaust gas containing a polycyclic aromatic compound with the exhaust gas deodorizer according to any one of [1] to

[11] above.

[13] A method for deodorizing exhaust gas according to the above

[12] , comprising contacting the exhaust gas with the exhaust gas deodorizer using a wet scrubber or a spray device that wet-collects the exhaust gas. [Example]

[0054] Hereinafter, one embodiment of the present invention will be described in more detail with reference to test examples, but the present invention is not limited to the following test examples.

[0055] <Test Example 1> [Simulated gas] A simulated gas containing polycyclic aromatic compounds, particularly naphthalene, was prepared and tested (e.g., exhaust gas from factories in the asphalt manufacturing industry, coal tar distillation and product manufacturing industry, petroleum product manufacturing industry, coal manufacturing industry, pesticide manufacturing industry, and paint manufacturing industry). The simulated gas components used were benzene, toluene, xylene, and styrene as monocyclic aromatic compounds, and indene, benzofuran, naphthalene, benzothiophene, 2-methylnaphthalene, 1-methylnaphthalene, biphenyl, quinoline, and acenaphthylene as polycyclic aromatic compounds.

[0056] [Test method] A 3-liter polyethylene terephthalate odor bag (product name "Odor Bag 3L" manufactured by Omi Odor Air Service Co., Ltd.) was filled with 1 mL of a chemical solution containing the specified concentration of the agent described below. After the chemical solution was poured into the odor bag, 1 L of simulated gas was injected into the odor bag using a glass syringe. After the simulated gas was injected into the odor bag, the odor bag was shaken and stirred 200 times to dissolve the chemical solution in droplets, simulating the state of the chemical solution being sprayed into the simulated gas. After 30–40 seconds, a detector tube (product name "Detector Tube Aromatic Hydrocarbon 120" manufactured by Gastec Corporation) was used to detect the total amount of aromatic compounds in the odor bag. The detected value (total amount of aromatic compounds) was read and the aromatic compound removal rate was evaluated. The reason for using an aromatic hydrocarbon detector tube was that a detector tube that only measures polycyclic aromatic compounds was unavailable.

[0057] [Medicines and solutions used] (Test Example 1A) In Test Example 1A, a polymer flocculant was used as the agent, aiming for the deodorizing effect based on the principle of utilizing the crosslinking of polymers described above (1).

[0058] In Test Example 1A-1, a liquid polymer flocculant product containing a cationic polyacrylamide polymer flocculant (product name "Aronflock E3580" (active ingredient concentration 40% by mass), manufactured by MT Aquapolymer Co., Ltd.) was used.

[0059] In Test Example 1A-2, a liquid polymer flocculant product containing an amphoteric polyacrylate ester-based polymer flocculant (product name "Himloc MX-5354H" (active ingredient concentration 40% by mass), manufactured by Hymo Co., Ltd.) was used.

[0060] In Test Example 1A-3, a granular anionic modified polyacrylamide polymer flocculant product (trade name "Acofloc A-245H", manufactured by MT Aquapolymer Co., Ltd.) was used.

[0061] In Test Examples 1A-1 to 1A-3, each polymer flocculant was diluted or dissolved in pure water to a concentration of 0.1% by mass to achieve a viscosity suitable for contacting actual exhaust gas with the deodorizer. In Test Examples 1A-1 to 1A-3, 1 mL of the flocculant was used per 1 L of simulated gas, resulting in a polymer flocculant concentration of 1 mg / 1 L of simulated gas. The aqueous solution used in Test Example 1A-1 had a pH of 7.5 and a viscosity of 107.0 mPa·s at 25°C. The aqueous solution used in Test Example 1A-2 had a pH of 4.0 and a viscosity of 106.2 mPa·s at 25°C. The aqueous solution used in Test Example 1A-3 had a pH of 7.3 and a viscosity of 373.2 mPa·s at 25°C.

[0062] (Test Example 1B) In Test Example 1B, lignin sulfonate was used as the agent, aiming at a deodorizing effect based on the principle of utilizing the π-π interaction acting between aromatic rings (2) described above.

[0063] In Test Example 1B-1, a liquid lignin product containing magnesium lignosulfonate (product name "Sunex M-100" (active ingredient concentration 50% by mass), manufactured by Nippon Paper Industries Co., Ltd., pH: 4.6, viscosity: less than 20 mPa·s) was used as the chemical solution.

[0064] In Test Example 1B-2, powdered calcium lignosulfonate (trade name "Sunex P202", manufactured by Nippon Paper Industries Co., Ltd.) was used, and an aqueous solution (pH: 6.2, viscosity: less than 20 mPa·s) prepared by adjusting the concentration of this calcium lignosulfonate with pure water to 50 mass% was used as the chemical solution.

[0065] In both Test Examples 1B-1 and 1B-2, 1 mL of the chemical solution was used per 1 L of the simulated gas, so the amount used as lignin sulfonate was 500 mg / 1 L of the simulated gas.

[0066] (Test Example 1C) In Test Example 1C, cyclodextrin was used as the agent, aiming at a deodorizing effect based on the principle of (3) inclusion action described above.

[0067] In Test Example 1C-1, α-cyclodextrin was dissolved in pure water, and an aqueous solution (pH: 8.4, viscosity: less than 20 mPa·s) with an α-cyclodextrin concentration of 9.7 mass % was used as the chemical solution.

[0068] In Test Example 1C-2, β-cyclodextrin was dissolved in pure water, and an aqueous solution (pH: 7.5, viscosity: less than 20 mPa·s) with a β-cyclodextrin concentration of 1.8 mass % was used as the chemical solution.

[0069] In Test Example 1C-3, γ-cyclodextrin was dissolved in pure water, and an aqueous solution (pH: 7.6, viscosity: less than 20 mPa·s) with a γ-cyclodextrin concentration of 13.0 mass % was used as the chemical solution.

[0070] In Test Example 1C-4, an aqueous solution containing 40% by mass of hydroxypropyl-β-cyclodextrin (product name "CAVASOL W7HPTL", manufactured by CycloChem Co., Ltd.) was diluted with pure water to adjust the concentration of hydroxypropyl-β-cyclodextrin to 13.0% by mass, and the resulting aqueous solution (pH: 11.6, viscosity: less than 20 mPa·s) was used as the chemical solution.

[0071] In each of Test Examples 1C-1 to 1C-4, 1 mL of the chemical solution was used per 1 L of simulated gas, so the amount of α-cyclodextrin used in Test Example 1C-1 was 97 mg / 1 L of simulated gas. Similarly, the amount of β-cyclodextrin used in Test Example 1C-2 was 18 mg / 1 L of simulated gas, the amount of γ-cyclodextrin used in Test Example 1C-3 was 130 mg / 1 L of simulated gas, and the amount of hydroxypropyl-β-cyclodextrin used in Test Example 1C-4 was 130 mg / 1 L of simulated gas.

[0072] (Test Example 1D) In Test Example 1D, various surfactants were used as the agent, aiming at the deodorizing effect based on the principle of utilizing the micelles of surfactants (4) described above.

[0073] In Test Example 1D-1, an aqueous solution (pH: 6.5, viscosity: less than 20 mPa·s) consisting of 10 mass % benzalkonium chloride, a type of cationic surfactant, and 90 mass % pure water was used as the chemical solution.

[0074] In Test Example 1D-2, an aqueous liquid (pH: 6.5, viscosity: less than 20 mPa·s) consisting of 10% by mass of sodium lauryl sulfate, which is a type of anionic surfactant, and 90% by mass of pure water was used as the chemical solution.

[0075] In Test Example 1D-3, an aqueous solution (pH: 6.5, viscosity: less than 20 mPa·s) consisting of 10 mass % polyethylene glycol dioleate (hereinafter sometimes referred to as "PEG-8 dioleate"), a type of nonionic surfactant with n=8 and HLB value=8.4, and 90 mass % pure water was used as the chemical solution.

[0076] In Test Example 1D-4, an aqueous solution (pH: 6.3, viscosity: 352.6 mPa s) consisting of 10% by mass of polyethylene glycol dioleate (hereinafter sometimes referred to as "PEG-12 dioleate"), a type of nonionic surfactant with n = 12 and HLB value = 10.4, and 90% by mass of pure water was used as the chemical solution.

[0077] In Test Example 1D-5, an aqueous solution (pH: 6.5, viscosity: 218.8 mPa s) consisting of 10% by mass of polyethylene glycol dioleate (hereinafter sometimes referred to as "PEG-20 dioleate"), a type of nonionic surfactant with n = 20 and HLB value = 12.9, and 90% by mass of pure water, was used as the chemical solution.

[0078] In Test Example 1D-6, an aqueous solution (pH: 7.0, viscosity: less than 20 mPa s) consisting of 10% by mass of polyoxyethylene (80) sorbitan monooleate (also known as Tween 80), a type of nonionic surfactant with an HLB value of 15.0, and 90% by mass of pure water was used as the chemical solution.

[0079] In Test Example 1D-7, an aqueous solution (pH: 7.0, viscosity: less than 20 mPa s) consisting of 10% by mass of polyoxyethylene (20) sorbitan monolaurate (also known as Tween 20), a type of nonionic surfactant with an HLB value of 17.0, and 90% by mass of pure water was used as the chemical solution.

[0080] In all of Test Examples 1D-1 to 1D-7, 1 mL of the chemical solution was used per 1 L of the simulated gas, so the amount used as a surfactant was 100 mg / 1 L of the simulated gas.

[0081] [Test Results] Tables 1 to 4 show the detection values ​​(total amount of aromatic compounds; vol. ppm) by the detector tube for each series of Test Examples 1A, 1B, 1C, and 1D. Each table also shows the results of the blank test conducted for each test example and the removal rate (removal rate of aromatic compounds; %) based on the blank test results. The blank test was conducted in a case where no chemical solution was used for 1 L of simulated gas (no addition). Note that when the test results were compared with the results of the blank test in a case where the same amount of water as the chemical solution (1 mL of pure water) was used, no difference was observed. Therefore, the test in which no chemical solution was used was used as the blank test (control test).

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[0086] The results of Test Example 1 showed that the removal rate of aromatic compounds was high when PEG-8 dioleate with an HLB value of 8.4 was used. From these results, it was inferred that certain nonionic surfactants have a deodorizing effect on odors caused by aromatic compounds.

[0087] <Test Example 2> In Test Example 1 (Test Examples 1C and 1D), nonionic surfactants and various cyclodextrins were found to have relatively high aromatic compound removal capabilities, and tests were conducted to determine which aromatic compounds contained in the simulated gas were most effective against these.

[0088] [Simulated gas] In Test Example 2, the same simulant gas as used in Test Example 1 was used. The total amount of aromatic compounds (10 vol. ppm) measured with the detector tube used in Test Example 1 was taken as the total amount of aromatic compounds contained in the simulant gas. The ratio of the peak area values ​​of each component (aromatic compound) in the simulant gas, determined using a gas chromatograph-mass spectrometer (hereinafter sometimes referred to as "GC-MS") described below, was then calculated as the amount of that component present in the simulant gas. This calculated value was taken as the estimated concentration (vol. ppm) of each aromatic compound in the simulant gas and is shown in Table 5.

[0089] TIFF0007793391000005.tif87170

[0090] [Test method] A 3-liter polyethylene terephthalate odor bag (product name "Odor Bag 3L" manufactured by Omi Odor Air Service Co., Ltd.) was filled with 1 mL of the chemical solution used in any of the aforementioned Test Examples 1C-1 to 1C-3 and Test Examples 1D-3 to 1D-7. After the chemical solution was placed in the odor bag, 1 L of simulated gas was injected into the odor bag using a glass syringe. After the simulated gas was injected into the odor bag, the odor bag was shaken up and down 200 times to agitate the chemical solution in the odor bag, simulating a state similar to that of spraying the chemical solution into the simulated gas. The gas inside the odor bag was then aspirated at 0.5 L / min using a small pump (product name "Mini Pump MP-W5P" manufactured by Shibata Scientific Co., Ltd.) and adsorbed into a Tenax adsorption tube. The gas adsorbed in the Tenax adsorption tube was measured by GC-MS. As a blank test, 1 mL of pure water was added to the odor bag instead of the chemical solution, and measurements were performed by GC-MS using the same procedure as above.

[0091] In each test, the peaks obtained by GC-MS measurement were used to calculate the removal rate (%) of each detected component (aromatic compound) using the following formula. Removal rate (%) = {GC measurement peak area value of blank test - GC measurement peak area value of test example after adding chemical solution} / GC measurement peak area value of blank test

[0092] [Medicines and solutions used] (Test Examples 2A-1 to 2A-3) In Test Example 2A, the chemical solution used in Test Examples 1C-1 to 1C-3 was used. Specifically, in Test Example 2A-1, the aqueous solution used in Test Example 1C-1, which had an α-cyclodextrin concentration of 9.7 mass%, was used as the chemical solution. In Test Example 2A-2, the aqueous solution used in Test Example 1C-2, which had a β-cyclodextrin concentration of 1.8 mass%, was used as the chemical solution. In Test Example 2A-3, the aqueous solution used in Test Example 1C-3, which had a γ-cyclodextrin concentration of 13.0 mass%, was used as the chemical solution.

[0093] (Test Examples 2B-1 to 2B-5) Test Example 2B used the same chemical solution as in Test Examples 1D-3 to 1D-7. Specifically, Test Example 2B-1 used the same aqueous solution as in Test Example 1D-3, consisting of 10% by mass of PEG-8 dioleate (n=8, HLB value=8.4) and 90% by mass of pure water. Test Example 2B-2 used the same aqueous solution as in Test Example 1D-4, consisting of 10% by mass of PEG-12 dioleate (n=12, HLB value=10.4) and 90% by mass of pure water. Test Example 2B-3 used the same aqueous solution as in Test Example 1D-5, consisting of 10% by mass of PEG-20 dioleate (n=20, HLB value=12.9) and 90% by mass of pure water. In Test Example 2B-4, the aqueous solution used in Test Example 1D-6 was 10% by mass of polyoxyethylene (80) sorbitan monooleate (also known as Tween 80, HLB value = 15.0) and 90% by mass of pure water.In Test Example 2B-5, the aqueous solution used in Test Example 1D-7 was 10% by mass of polyoxyethylene (20) sorbitan monolaurate (also known as Tween 20, HLB value = 17.0) and 90% by mass of pure water.

[0094] The measurement conditions for the above GC-MS are as follows: Gas chromatograph (GC): Product name "7890A", manufactured by Agilent Technologies ·Mass spectrometer (MS): Product name “5975C”, manufactured by Agilent Technologies Column: Product name "DB-WAX" (length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm), manufactured by Agilent Technologies Injector: Curie point injector: Product name "JCI-22", manufactured by Japan Analytical Industry Co., Ltd. Oven: 40°C (8 mins) - Heating rate 10°C / min - 220°C (18 mins) Total 40 mins ·GC inlet: 220℃, splitless column flow rate: 1mL / min MS interface: 300℃ MS detection conditions: SCAN measurement (m / z 20-600)

[0095] [Test Results] The results of the aromatic compound removal rates (%) for each series of Test Examples 2A and 2B are shown in Tables 6 and 7. As shown in Table 5 above, the estimated concentrations of biphenyl, quinoline, and acenaphthylene in the simulated gas were less than 0.1 vol.ppm, so they were omitted from the test results for Test Examples 2 and 3.

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[0098] The results of Test Example 2 confirmed that PEG-8 dioleate, with an HLB value of 8.4, has excellent ability to remove polycyclic aromatic compounds such as naphthalene from simulated gases. These results suggest that an aqueous liquid (deodorizer) containing a specific nonionic surfactant has a deodorizing effect on odors caused by polycyclic aromatic compounds when used on exhaust gases containing polycyclic aromatic compounds.

[0099] <Test Example 3> The test was carried out in the same manner as in Test Example 1, except that the simulated gas used in Test Example 1 was changed to a simulated gas containing naphthalene and indene, and the chemical solution used in Test Example 1 was changed to the chemical solution described below. As a blank test, the total amount of aromatic compounds in the simulated gas used was measured using the above detector tube, and the result was 10 vol.ppm.

[0100] (Test Example 3.1) The agent used was an aqueous solution (pH: 8.5, viscosity: less than 20 mPa·s) in which the concentration (active ingredient) of sorbitan monooleate (trade name "Ionet S-80", manufactured by Sanyo Chemical Industries, Ltd.), a type of nonionic surfactant with an HLB value of 4.3, was adjusted with water to 10% by mass (pH: 8.5, viscosity: less than 20 mPa·s).

[0101] (Test Example 3.2) The agent used was an aqueous solution (pH: 6.5, viscosity: less than 20 mPa·s) in which the concentration (active ingredient) of polyoxyethylene polyoxypropylene alkyl ether (trade name "Pepol A-0638", manufactured by Toho Chemical Industry Co., Ltd.), a type of nonionic surfactant with an HLB value of 5.1, was adjusted with water to 10% by mass (pH: 6.5, viscosity: less than 20 mPa·s).

[0102] (Test Example 3.3) The agent used was an aqueous solution (pH: 7.6, viscosity: less than 20 mPa·s) in which the concentration (active ingredient) of a polyoxyalkylene alkyl ether (product name "Cedran SF-506", manufactured by Sanyo Chemical Industries, Ltd.), a type of nonionic surfactant with an HLB value of 6.1, was adjusted with water to 10% by mass (pH: 7.6, viscosity: less than 20 mPa·s).

[0103] (Test Example 3.4) The agent used was an aqueous solution (pH: 6.5, viscosity: less than 20 mPa·s) in which the concentration (active ingredient) of polyoxyethylene hydrogenated castor oil (product name "Sorpol HC-10", manufactured by Toho Chemical Industry Co., Ltd.), a type of nonionic surfactant with an HLB value of 6.4, was adjusted with water to 10% by mass (pH: 6.5, viscosity: less than 20 mPa·s).

[0104] (Test Example 3.5) The agent used was an aqueous solution (pH: 6.4, viscosity: 81.0 mPa·s) in which the concentration (active ingredient) of polyoxyethylene alkyl ether (trade name "Naroacty CL-40", manufactured by Sanyo Chemical Industries, Ltd.), a type of nonionic surfactant with an HLB value of 8.4, was adjusted with water to 10% by mass (pH: 6.4, viscosity: 81.0 mPa·s).

[0105] (Test Example 3.6) The agent used was an aqueous solution (pH: 6.5, viscosity: less than 20 mPa·s) in which the concentration (active ingredient) of PEG-8 dioleate (trade name "IONET DO-400", manufactured by Sanyo Chemical Industries, Ltd.), a type of nonionic surfactant with an HLB value of 8.4, was adjusted with water to 10% by mass (pH: 6.5, viscosity: less than 20 mPa·s).

[0106] (Test Example 3.7) The agent used was an aqueous solution (pH: 6.3, viscosity: 352.6 mPa·s) of PEG-12 dioleate (trade name "IONET DO-600", manufactured by Sanyo Chemical Industries, Ltd.), a type of nonionic surfactant with an HLB value of 10.4, adjusted to a concentration (active ingredient) of 10% by mass with water.

[0107] (Test Example 3.8) The agent used was an aqueous solution (pH: 6.5, viscosity: 218.8 mPa·s) of PEG-20 dioleate (trade name "IONET DO-1000", manufactured by Sanyo Chemical Industries, Ltd.), a type of nonionic surfactant with an HLB value of 12.9, adjusted to a concentration (active ingredient) of 10% by mass with water.

[0108] (Test Example 3.9) The agent used was an aqueous solution (pH: 6.5, viscosity: less than 20 mPa·s) in which the concentration (active ingredient) of sucrose laurate (trade name "Ryoto Sugar Ester LWA-1570", manufactured by Mitsubishi Chemical Foods Corporation), a type of nonionic surfactant with an HLB value of 15.0, was adjusted with water to 10% by mass (pH: 6.5, viscosity: less than 20 mPa·s).

[0109] (Test Example 3.10) The drugs used were aqueous solutions (pH: 6.5, viscosity: less than 20 mPa·s) in which the concentrations of γ-cyclodextrin and PEG-8 dioleate with an HLB value of 8.4 were adjusted to 0.7% by mass and 5.0% by mass, respectively, with water.

[0110] (Test Example 3.11) The drugs used were aqueous solutions (pH: 6.2, viscosity: 25.8 mPa·s) in which the concentrations of PEG-8 dioleate with an HLB value of 8.4 and polyoxyethylene polyoxypropylene alkyl ether with an HLB value of 5.1 were adjusted to 5.0% by mass with water, respectively.

[0111] (Test Example 3.12) The drugs used were aqueous solutions (pH: 6.3, viscosity: 40.2 mPa·s) in which the concentrations of the polyoxyethylene polyoxypropylene alkyl ether with an HLB value of 5.1 and the polyoxyethylene alkyl ether with an HLB value of 8.4 were adjusted to 5.0 mass% and 5.0 mass%, respectively, with water.

[0112] (Test Example 3.13) The agent used was an aqueous solution (pH: 7.2, viscosity: less than 20 mPa·s) in which the concentrations of PEG-8 dioleate and 2-phenoxyethanol, both with an HLB value of 8.4, were adjusted to 5.0% by mass and 5.0% by mass, respectively, with water.

[0113] The results of Test Example 3 (Test Examples 3.1 to 3.13) are shown in Table 8.

[0114] TIFF0007793391000008.tif189170

[0115] The results of Test Examples 1 to 3 confirmed that nonionic surfactants with an HLB value of 4 to 10 have excellent removal ability for polycyclic aromatic compounds such as naphthalene in simulated gases. These results confirmed that an aqueous liquid (deodorizer) containing a nonionic surfactant with an HLB value of 4 to 10 has a deodorizing effect on odors caused by polycyclic aromatic compounds when used on exhaust gases containing polycyclic aromatic compounds.

[0116] <Test Example 4> In Test Example 4, a test was conducted using an impinger, simulating a case in which a wet scrubber was used to bring exhaust gas into contact with a deodorizer. The same simulant gas used in Test Examples 1 and 2 was used as the gas containing polycyclic aromatic compounds. The deodorizing performance was confirmed using the same GC-MS, including the same measurement conditions, as used in Test Example 2.

[0117] [Test method] A 250 mL impinger was filled with 200 mL of the chemical solution described below. After filling the impinger with the chemical solution, 500 mL of simulated gas was injected into the impinger, replacing the air inside the impinger with the simulated gas. Then, 1 L of simulated gas was injected into the impinger using a syringe. The gas that passed through the chemical solution inside the impinger was collected in a 3 L polyethylene terephthalate odor bag (product name "3 L Smell Bag" manufactured by Omi Odor Air Service Co., Ltd.). The gas inside the odor bag was then aspirated at 0.5 L / min using a small pump (product name "Mini Pump MP-W5P" manufactured by Shibata Scientific Co., Ltd.) and adsorbed into a Tenax adsorption tube. The gas adsorbed in the Tenax adsorption tube was measured by GC-MS. Additionally, a blank test 4A was conducted by emptying the impinger, passing 1 L of simulated gas through it, and measuring the gas by GC-MS using the same method as above. Furthermore, as Blank Test 4B, 200 mL of pure water was filled into the impinger instead of the aqueous liquid, and 1 L of simulated gas was passed through in the same manner as above, and measurement was performed by GC-MS. In each test of Test Example 4, the peaks obtained by GC-MS measurement were used, and the removal rate (%) of each detected component (aromatic compound) was calculated using the formula described in Test Example 2, with the results of Blank Tests 4A and 4B as the standard.

[0118] [Medicines and solutions used] (Test Examples 4-1 to 4-3) In Test Example 4, the same PEG-8 dioleate (n = 8, HLB value = 8.4) used in Test Example 2B-1 was used as the chemical agent, and an aqueous solution prepared by adjusting this to a predetermined concentration with water was used as the chemical agent. Specifically, in Test Example 4-1, an aqueous solution (pH: 6.5, viscosity: less than 20 mPa·s) containing 1.0% by mass of PEG-8 dioleate was used. In Test Example 4-2, an aqueous solution (pH: 6.5, viscosity: less than 20 mPa·s) containing 0.1% by mass of PEG-8 dioleate was used. In Test Example 4-3, an aqueous solution (pH: 6.5, viscosity: less than 20 mPa·s) containing 0.02% by mass of PEG-8 dioleate was used. In Test Example 4, 200 mL of the chemical agent was filled in a 250 mL container, and 1 L of simulated gas was passed through the 200 mL of the chemical agent. Therefore, in Test Example 4, the amount of surfactant (PEG-8 dioleate) used per 1 L of simulated gas was 2000 mg / L in Test Example 4-1, 200 mg / L in Test Example 4-2, and 40 mg / L in Test Example 4-3.

[0119] [Test Results] The results of the aromatic compound removal rate (%) based on Blank Test 4A for each series of Test Example 4 are shown in Table 9. The results of the aromatic compound removal rate (%) based on Blank Test 4B for each series of Test Example 4 are shown in Table 10.

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[0122] The results of Test Examples 1 to 4 showed that an aqueous liquid containing a nonionic surfactant with an HLB value of 4 to 10 had a high removal rate of 60% or more of all polycyclic aromatic compounds in the simulated gas, even when the amount of surfactant used was small (see Table 9). These results confirmed that an aqueous liquid (deodorizer) containing a nonionic surfactant with an HLB value of 4 to 10 can more effectively remove odors caused by polycyclic aromatic compounds when used on exhaust gas containing polycyclic aromatic compounds.

[0123] Furthermore, in the aforementioned Test Example 2, PEG-8 dioleate was hardly observed to have the ability to remove toluene and xylene, which are monocyclic aromatic compounds (see Table 7), but in Test Example 4, it appeared to have the ability to remove toluene and xylene. However, in Blank Test 4B, in which pure water was used instead of the chemical solution, the ability to remove toluene and xylene was also observed, which suggests that these monocyclic aromatic compounds were dissolved in water (see Table 10).

[0124] Test Examples 4-1 and 4-2, in which the concentration of PEG-8 dioleate was 0.1% by mass or more, showed higher polycyclic aromatic compound removal ability than Blank Test 4B (see Table 10). This shows that in a deodorizing method using a wet scrubber, which can use a large amount of water, using an aqueous liquid containing a nonionic surfactant with an HLB value of 4 to 10 as a deodorizer can be expected to effectively deodorize not only polycyclic aromatic compounds but also odors caused by monocyclic aromatic compounds.

[0125] <Test Example 5> In Test Example 5, a test similar to Test Example 2 was conducted, except that the simulated gas used in Test Example 2 was changed to the simulated gas described below, and the chemical liquid used in Test Example 2 was changed to the chemical liquid described below.

[0126] [Simulated gas] The simulant gas used in Test Example 5 differs in the composition ratio of components from the simulant gas used in Test Example 2. Specifically, the simulant gas used in Test Example 2 contained 80% or more of polycyclic aromatic compounds (main component: naphthalene) among the aromatic compounds, whereas the simulant gas used in Test Example 5 contained 80% or more of monocyclic aromatic compounds (main component: benzene) among the aromatic compounds.

[0127] The total amount of aromatic compounds in the simulated gas used in Test Example 5 was detected using a detector tube (product name "Detector Tube Aromatic Hydrocarbon 120", manufactured by Gastec Corporation), and the total amount of aromatic compounds was found to be 160 vol.ppm. The estimated concentration (vol.ppm) of each aromatic compound in the simulated gas was then determined using the same method as described in Test Example 2. The results are shown in Table 11.

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[0129] [Medicines and solutions used] In Test Example 5, PEG-8 dioleate (n=8, HLB value=8.4) was used as the chemical agent, and an aqueous solution (pH: 6.5, viscosity: less than 20 mPa s) prepared by dissolving this in water to a concentration of 1.0% by mass was used as the chemical solution. The blank test was also conducted in the same manner as in Test Example 2, except that pure water was used instead of the chemical solution.

[0130] [Test Results] The results of the aromatic compound removal rate (%) in Test Example 5 are shown in Table 12.

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[0132] The results of Test Example 5 confirmed that even for exhaust gas in which the proportion of monocyclic aromatic compounds in the aromatic compounds is higher than the proportion of polycyclic aromatic compounds, by using an aqueous liquid containing a nonionic surfactant with an HLB value of 4 to 10, it is possible to effectively deodorize the odor caused by polycyclic aromatic compounds in the exhaust gas.

[0133] <Test Example 6> [Simulated gas] The following simulated gases 1 and 2 were used. Simulated gas 1: A simulated gas containing benzene, toluene, ethylbenzene, xylene, styrene, trimethylbenzene, methylstyrene, ethyltoluene, indane, indene, benzofuran, methylindene, naphthalene, benzothiophene, 2-methylnaphthalene, and 1-methylnaphthalene. The total amount of aromatic compounds measured with the detector tube for Simulated Gas 1 was above 200 vol.ppm, the upper limit of detection for the detector tube (exceeding the upper limit). Simulated gas 2: Simulated gas containing indene and naphthalene. The total amount of aromatic compounds measured with the detector tube for Simulated Gas 2 was 10 vol.ppm.

[0134] [Test method] Odorless air was prepared using a nine-way activated carbon tank filled with activated carbon and a 60L odorless air pump (manufactured by Omi Odor Air Service Co., Ltd.). 300 mL of simulated gas was injected with a glass syringe into a 3L gas sampling bag (a 3L polyethylene terephthalate odor bag (product name "Odor Bag 3L", manufactured by Omi Odor Air Service Co., Ltd.)) filled with 2.7 L of odorless air to prepare the test gas. A test gas without any added chemicals was used as a blank. 1 mL of deodorant (aqueous liquid) was added to a similarly prepared 3L test gas bag, sealed, and stirred 200 times to prepare a deodorant-added sample. An aqueous liquid containing PEG-8 dioleate (0.01% by mass) with an HLB value of 8.4 and a masking fragrance (0.01% by mass) was used as the deodorant. After stirring, each gas sample was used in the olfactory sensory evaluation test described below.

[0135] The olfactory sensory evaluation test was conducted using a human olfactory sense, using a 9-point pleasantness / unpleasantness scale (-4: extremely unpleasant, -3: very unpleasant, -2: unpleasant, -1: slightly unpleasant, 0: neither pleasant nor unpleasant, 1: slightly pleasant, 2: pleasant, 3: very pleasant, 4: extremely pleasant). The sensory test was conducted by six panelists (A-F), and the highest and lowest scores of the six were excluded, and the average of the scores of the other four was calculated as a score. The score was rounded up to the nearest whole number and judged as the pleasantness / unpleasantness level. The results are shown in Table 13.

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[0137] The comfort / discomfort scale for simulated gas 1 was -2, judging it to be unpleasant. In contrast, the comfort / discomfort scale for simulated gas 1 with deodorant added was -1, judging it to be slightly unpleasant, confirming its deodorizing effect. Furthermore, the comfort / discomfort scale for simulated gas 2 was -4, judging it to be extremely unpleasant. In contrast, the comfort / discomfort scale for simulated gas 2 with deodorant added was -1, judging it to be slightly unpleasant, confirming its deodorizing effect. When the same samples were measured using the detector tube, the values ​​for simulated gas 1, both unadded and with deodorant added, were above the detection limit of 200 vol.ppm (far above the upper limit), and the color change range could not be read. For simulated gas 2, the unadded sample had a value of 10 vol.ppm, while the deodorant-added sample had a value of 3 vol.ppm, confirming that the addition of the deodorant reduced the total amount of aromatic compounds.

[0138] <Test Example 7> [Preparation of deodorant] The components (unit: mass %) shown in the upper row of Table 14 (Table 14-1 and Table 14-2) were mixed to prepare a deodorant (deodorant before dilution). Specifically, water, PEG-8 dioleate (n=8, HLB value=8.4), blended fragrance (any of A to C), and solvent (any of 2-phenoxyethanol, ethanol, and acetonitrile) were placed in a container in the proportions (mass %) shown in the upper row of Table 14, and the mixture was stirred by shaking up and down about 50 times at room temperature (about 25°C) to prepare a deodorant solution. Blended fragrances A to C shown in Table 14 are as follows.

[0139] · Blended fragrance A (soap scent); It consists of 20.0% by mass of alcohols (phenethyl alcohol, geraniol, citronellol, etc.), 13.0% by mass of esters (benzyl acetate, linalyl acetate, p-tert-butylcyclohexyl acetate, etc.), 6.4% by mass of aldehydes (hexyl cinnamaldehyde, etc.), 8.0% by mass of others (coumarin, indole, and gamma-decalactone), and 52.6% by mass of solvent (dipropylene glycol). · Blended fragrance B (herbal green scent); It consists of 12.0% by mass of alcohols (terpineol, etc.), 15.0% by mass of esters (isobornyl acetate, etc.), 20.0% by mass of hydrocarbon terpenes (d-limonene, etc.), 9.0% by mass of natural fragrances (eucalyptus oil, etc.), 6.0% by mass of other types (coumarin, dl-camphor, etc.), and 38.0% by mass of solvents (ethyl alcohol, dipropylene glycol). Blended fragrance C (a soapy fragrance with a different scent tone from A); It consists of 50.2% by mass of alcohols (phenethyl alcohol, geraniol, citronellol, linalool, etc.), 26.3% by mass of esters (p-tert-butylcyclohexyl acetate, benzyl acetate, linalyl acetate, etc.), 4.5% by mass of aldehydes (hexyl cinnamaldehyde, etc.), 8.4% by mass of others (coumarin, γ-methyl ionone), and 10.6% by mass of solvents (dipropylene glycol, etc.).

[0140] [Solution stability during mixing] The deodorant solution prepared as described above was allowed to stand for 2 hours after stirring, and the state of the solution was then visually inspected, and the stability of the solution when the components were mixed was evaluated according to the following evaluation criteria. The results are shown in the bottom row of Table 14. ○: Uniform state without separation. ×: Separated state.

[0141] [Test method] A simulated gas containing naphthalene and indene was used as the deodorizing target. This simulated gas was the same as the simulated gas used in Test Example 3. Each deodorant (undiluted deodorant) prepared as described above was diluted 100 times with water to obtain the diluted deodorants (diluted deodorants) shown in the middle of Table 14. Tests were conducted using the same methods as Test Examples 1 and 3, with 1 mL of this diluted deodorant added to 1 L of simulated gas. The total amount of aromatic compounds was measured using a detector tube in the same manner as in Test Examples 1 and 3. The results are shown in the bottom of Table 14. The total amount of aromatic compounds was measured using the detector tube for the simulated gas used, and the aromatic compound removal rate (%) was also shown in the bottom of Table 14, based on the blank test result of 10 vol. ppm. Note that no difference was observed when the test results were compared between the test results using the same amount of water (1 mL of pure water) as the diluted deodorant used and the blank test results. Therefore, a test without any added additives was used as a blank test (control test).

[0142] TIFF0007793391000014.tif131170

[0143] TIFF0007793391000015.tif131170

[0144] [Sensory test] The simulated gas was diluted approximately 50 times with air and used. The deodorants prepared in Test Examples 7.4 and 7.6 (undiluted deodorants) were diluted 5,000 times with water to obtain diluted deodorants. An olfactory sensory evaluation test was conducted in the same manner as in Test Example 6, with 1 mL of this diluted deodorant added to 1 L of simulated gas. However, the evaluation was conducted by four panelists (A to D), and the average value was calculated. A sample to which nothing was added to 1 L of simulated gas was used as a blank. The results are shown in Table 15.

[0145] TIFF0007793391000016.tif34170

[0146] The results of Test Example 7 confirmed that an aqueous liquid containing a nonionic surfactant with an HLB value of 4 to 10, a fragrance, and a specific solvent (separation inhibitor) is highly safe, does not easily separate, and has good stability, and has a deodorizing effect on odors caused by polycyclic aromatic compounds in exhaust gases.

Claims

1. A deodorizer for use in exhaust gas containing polycyclic aromatic compounds, An aqueous liquid exhaust gas deodorizer containing a nonionic surfactant having an HLB value of 4 to 10 according to the Griffin method and 2-phenoxyethanol.

2. The deodorant further contains a fragrance and a separation inhibitor for inhibiting separation of the fragrance in the deodorant, 2. The exhaust gas deodorizer according to claim 1, wherein the separation inhibitor is at least one selected from the group consisting of 2-phenoxyethanol, ethanol, and acetonitrile.

3. A deodorizer for use on exhaust gas containing polycyclic aromatic compounds, comprising: The deodorant contains a nonionic surfactant having an HLB value of 4 to 10 according to the Griffin method, a fragrance, and a separation inhibitor for inhibiting separation of the fragrance in the deodorant, The separation inhibitor is an aqueous liquid exhaust gas deodorizer that is at least one selected from the group consisting of 2-phenoxyethanol, ethanol, and acetonitrile.

4. The exhaust gas deodorizer according to any one of claims 1 to 3, wherein the nonionic surfactant comprises at least one selected from the group consisting of polyethylene glycol fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyalkylene alkyl ethers, and sorbitan fatty acid esters.

5. The exhaust gas deodorizer according to any one of claims 1 to 4, wherein the nonionic surfactant comprises at least one selected from the group consisting of polyethylene glycol fatty acid ester, polyoxyethylene hydrogenated castor oil, and polyoxyethylene alkyl ether.

6. The exhaust gas deodorizer according to any one of claims 1 to 5, comprising a plurality of types of nonionic surfactants having different HLB values.

7. The exhaust gas deodorizer according to any one of claims 1 to 6, further comprising cyclodextrin.

8. The exhaust gas deodorizer according to any one of claims 1 to 7, which is diluted with water and then sprayed.

9. The exhaust gas deodorizer according to any one of claims 1 to 8, which has a viscosity of 500 mPa·s or less at 25°C.

10. The exhaust gas deodorizer according to any one of claims 1 to 9, wherein the polycyclic aromatic compound comprises at least one selected from the group consisting of naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, biphenyl, benzothiophene, quinoline, and acenaphthylene.

11. The exhaust gas deodorizer according to any one of claims 1 to 10, wherein the polycyclic aromatic compound contains at least naphthalene.

12. A method for deodorizing exhaust gas, comprising contacting exhaust gas containing a polycyclic aromatic compound with the exhaust gas deodorizer according to any one of claims 1 to 11.

13. The method for deodorizing exhaust gas according to claim 12, comprising contacting the exhaust gas with the exhaust gas deodorizer using a wet scrubber that wet-collects the exhaust gas or a spray device.

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