JP2007038106A - Deodorization method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deodorization method with which hydrogen sulfide and/or thiols (acidic gas), sulfides and/or disulfides (sulfur-based neutral gas), ammonia and/or amines (basic gas), and lower aldehydes from gases containing at least these four malodor components can be efficiently removed over a long period of time, and which can be excellently applied to an existing facility (apparatus). <P>SOLUTION: In this deodorization method, gases containing at least hydrogen sulfide and/or thiols, sulfides and/or disulfides, ammonia and/or amines, and lower aldehydes are first brought into contact with a first adsorbent formed by carrying halogens, nonvolatile acid and an alkaline metal halide on a porous carrier, then to a second absorbent formed by carrying saturated cyclic secondary amine and an alkaline metal halide or an alkaline earth metal halide on the porous carrier. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a deodorizing method, and more specifically, hydrogen sulfide and / or mercaptans (acid gas), sulfides and / or disulfides (sulfur-based neutral gas), ammonia and / or amines (basic gas). And a deodorizing method capable of obtaining an excellent deodorizing effect over a long period against malodorous gas containing at least a lower aldehyde.

  Conventionally, porous adsorbents such as activated carbon, activated clay, silica gel, activated alumina, and clay mineral have been used as adsorbents for adsorbing and removing malodorous components (bad odorous substances) in malodorous gases. In addition, the adsorptivity of the porous adsorbing material itself does not provide a high adsorption amount for various malodorous substances. Therefore, the porous adsorbing material is used as a carrier and can react with the malodorous substance. Adsorption effects (deodorizing effects) on various malodorous substances have been improved by supporting more than one kind of compound. For example, an adsorbent in which a metal halide such as potassium iodide and an inorganic acid such as phosphoric acid are supported on activated carbon (Patent Document 1), a halogen such as bromine and an inorganic acid such as phosphoric acid are supported on activated carbon or the like. There is an adsorbent (Patent Document 2) and an adsorbent (Patent Document 3) in which a metal halide such as potassium iodide, an inorganic acid such as phosphoric acid, and a halogen such as bromine are supported on activated carbon. In addition, a combination of a plurality of adsorbents with different compounds supported on a porous adsorbing material (carrier), or a compound capable of reacting with a malodorous substance is not supported on a porous adsorbing material (porous adsorbing material alone). A technique relating to a method for enhancing the effect of removing a plurality of malodorous substances by using in combination with an adsorbent carrying a compound capable of reacting with malodorous substances is also known (Patent Document 4).

  By the way, lower aldehydes represented by formaldehyde, acetaldehyde, and the like are toxic gases having a unique irritating odor, and formaldehyde has an acceptable concentration in air of 0.5 ppm, and acetaldehyde is designated as a malodorous substance. ing. Formaldehyde generation sources include formaldehyde manufacturing plants, urea, melamine, phenol, etc. and resin manufacturing plants using formaldehyde as raw materials, processing plants using these resins, and building materials using these resins, Examples include manufacturing plants for various processed products such as furniture. It is also said to be generated from incomplete combustion of formalin and petroleum stoves used as disinfectants, and to be contained in a lot of sidestream smoke. As a source of acetaldehyde, it is generated in the heat treatment of sewage sludge, as well as in the mainstream smoke of cigarettes, in addition to the manufacturing plant of acetaldehyde and its derivatives. In recent years, these lower aldehydes have been considered to be harmful and odorous from both aspects of improving the working environment and living environment, and there has been a strong demand for effective detoxification measures, and adsorbents for that purpose have also been proposed. (For example, Patent Documents 5 and 6).

However, in the exhaust gas generated from biological deodorization facilities at sewage treatment plants, sludge incineration facilities, human waste treatment, plant facilities at incineration plants, etc., in addition to lower aldehydes, hydrogen sulfide and / or mercaptans (acid gases), sulfides And / or disulfides (sulfur-based neutral gas), ammonia and / or amines (basic gas), and other types of malodorous components such as lower aldehydes, hydrogen sulfide and / or mercaptans. All these malodorous components are sufficiently removed by adsorption from odorous gases (acid gases), sulfides and / or disulfides (sulfur-based neutral gases), and odorous gases in which ammonia and / or amines (basic gases) coexist. No adsorbent that can be found has been found. Further, three or more kinds of adsorbents are usually used for removing these multi-component malodorous components. Therefore, in recent years, a composite odor deodorant obtained by mixing porous bodies having different adsorbing components has been proposed with the aim of overcoming the above problems (Patent Document 7). However, such a mixed odor deodorant mixed with porous materials with different adsorbing components inevitably increases the adsorbing band width of the gas component to be adsorbed, so a sufficient adsorbing band width must be secured. For example, malodorous components leak at an early stage, and the amount of the malodorous component increases slowly over a long period. On the other hand, if a sufficient width of the adsorbing zone is secured, the deodorization equipment becomes large, and it cannot be said that it is appropriate in view of the recent social situation where awareness of “environmental consideration” is strongly demanded. Further, the odor intensity (threshold value) of gas varies in concentration depending on the gas. For example, the concentration values of lower aldehydes, mercaptans, and sulfides are extremely low. Therefore, in a system containing such a gas, an adsorbent with a short adsorption band in which a leak can be found immediately even with a small amount is preferable, but a mixture of porous bodies (adsorbents) with different adsorbing components is not suitable. Since the width of the adsorption band is inevitably increased, the user's replacement judgment is lost, which is not an appropriate adsorbent.

In Patent Document 4, malodorous gas in which hydrogen sulfide and / or mercaptans, sulfides and / or disulfides, ammonia and / or amines coexist is first contacted with activated carbon (first treatment), Next, it can be almost completely deodorized by contacting with activated carbon or clay mineral carrying acid (second treatment) and then contacting with activated carbon in the presence of bromine or chlorine (third treatment). In addition to these malodorous components, even if a lower aldehyde further coexists, it is said that the lower aldehyde can also be removed. However, in the deodorization method described in the document, the adsorbent to be packed into the treatment column must be divided and packed into three layers of the gas inlet side layer, the intermediate layer, and the gas outlet side layer. There is also a problem that the total amount of adsorbent is increased. In particular, when deodorizing malodorous gas coexisting with lower aldehydes, odor leakage (leak) occurs at an early stage, and the life of the activated carbon is shortened, requiring early replacement of the adsorbent, Furthermore, there is a problem that further enlargement of the deodorizing equipment is required to sufficiently remove the lower aldehydes. That is, when a gas in which lower aldehydes coexist is introduced, lower aldehydes are removed by activated carbon in the first treatment, and thus activated carbon in the first treatment works to remove hydrogen sulfide and / or mercaptans and lower aldehydes. Therefore, an excessive load is applied to the activated carbon of the first treatment, and as a result, an early replacement of the adsorbent is required. In addition to the first to third treatments, the literature finally treats the activated carbon ( It is said that perfect deodorization is possible by performing the (fourth treatment). However, if the activated carbon of the fourth treatment is provided, the deodorization device is further increased in size, resulting in higher pressure loss and higher operation and maintenance costs. The problem of becoming.
JP 57-99334 A Japanese Patent Laid-Open No. 06-126166 JP 2001-129392 A JP-A-55-51422 JP-A-4-358536 JP 2000-84406 A JP 2005-152726 A

  In view of the above circumstances, the problem to be solved by the present invention is that hydrogen sulfide and / or mercaptans (acid gas), sulfides and / or disulfides (sulfur-based neutral gas), ammonia and / or amines (base) These four types of malodorous components can be removed efficiently from gas containing at least lower aldehydes over a long period of time, and it is not necessary to increase the size of deodorizing equipment, and can be applied to existing equipment (equipment). It is to provide a deodorizing method that is also excellent in properties.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research, and as a result, have found hydrogen sulfide and / or mercaptans, sulfides and / or disulfides, ammonia and / or amines, and lower aldehydes. By contacting at least a gas containing at least two specific types of adsorbents in a specific order, the four types of malodorous components can be efficiently removed over a long period of time while using only two types of adsorbents. As a result, the present invention has been completed.

That is, the present invention is as follows.
(1) A gas containing at least hydrogen sulfide and / or mercaptans, sulfides and / or disulfides, ammonia and / or amines, and lower aldehydes is firstly halogenated, nonvolatile acid and alkali metal halide. Is contacted with a first adsorbent supported on a porous carrier, and then a saturated cyclic secondary amine and an alkali metal or alkaline earth metal halide are brought into contact with a second adsorbent supported on the porous carrier. A deodorizing method characterized by
(2) The deodorization method according to (1) above, wherein the porous carriers of the first and second adsorbents are both activated carbon, and (3) the halogen in the first adsorbent is bromine and the non-volatile acid is sulfuric acid. (1) or (2) above, wherein the alkali metal halide is an alkali metal iodide, and the alkali metal or alkaline earth metal halide in the second adsorbent is an alkali metal or alkaline earth metal iodide. Deodorizing method as described,
About.

  According to the deodorization method of the present invention, hydrogen sulfide and / or mercaptans (acid gas), sulfides and / or disulfides (sulfur-based neutral gas), ammonia and / or amines (basic gas), and lower aldehyde These four kinds of malodorous components can be efficiently removed over a long period of time from a gas containing at least a kind, and an excellent deodorizing effect can be obtained. Further, since only two kinds of adsorbents are used, there is no need to increase the size of the processing column, and there is no problem that the pressure loss increases and the operation and maintenance costs increase.

  In the present invention, “deodorization” refers to hydrogen sulfide and / or mercaptans (acid gas), sulfides and / or disulfides (sulfur-based neutral gas), ammonia and / or amines (basic gas) and That is, at least these four types of malodorous components are reduced from the gas containing at least the lower aldehydes, and the odors of these four types of malodorous components are not substantially felt.

Hereinafter, the present invention will be described in more detail.
The deodorization method of the present invention comprises a gas containing at least hydrogen sulfide and / or mercaptans, sulfides and / or disulfides, ammonia and / or amines, and lower aldehydes, first halogen, nonvolatile acid and Second adsorption in which an alkali metal halide is contacted with a first adsorbent supported on a porous carrier, and then a saturated cyclic secondary amine and an alkali metal or alkaline earth metal halide are supported on the porous carrier. It is characterized by contacting with an agent.

<First adsorbent>
The first adsorbent used in the present invention is obtained by supporting a halogen, a nonvolatile acid and an alkali metal halide on a porous carrier.

  Examples of the porous carrier include various porous adsorbing materials such as activated carbon, activated clay, zeolite, silica gel, activated alumina, and clay mineral. Among these, activated carbon is preferably used.

  When using activated carbon, the raw materials include, for example, plant raw materials such as wood powder and coconut shells, coal such as anthracite, petroleum pitch, coke, petroleum raw materials, acrylic resins, phenol resins, epoxy resins, polyester resins, etc. Among them, resin-based raw materials can be mentioned, and among them, coal such as coconut shell charcoal, anthracite coal, petroleum pitch, and coke obtained from coconut shell is preferable. These activated carbon raw materials are activated in, for example, a fixed bed, a moving bed, a fluidized bed, and the like. The activation includes, for example, gas activation using water vapor, chlorine, hydrogen chloride, carbon monoxide, carbon dioxide, oxygen, etc., and chemical activation using chemicals such as alkali, acid or zinc chloride, etc., which are used in the present invention. The activated carbon may be activated by any of them.

  Active clay is an adsorbing material obtained by treating sulfuric acid with clay called acid clay or fuller's earth, and contains montmorillonite as a main component. Zeolite generally refers to hydrous aluminosilicate, which is an adsorbent obtained by drying a gel made from sodium hydroxide aqueous solution with sodium silicate etc. as a silica source and aluminum hydroxide as an alumina source. Yes, with molecular sieving action and selectivity for polar molecules. Silica gel is an adsorbent material obtained by treating an aqueous sodium silicate solution with sulfuric acid to form a gel and washing and removing the sodium sulfate with water, and has selectivity for polar molecules. Activated alumina is an adsorbing material obtained by heating and dehydrating alumina trihydrate and has selectivity for polar molecules.

The particle diameter of the activated carbon is usually 0.01 to 15 mm, preferably 0.1 to 10 mm, and the activated carbon has a BET specific surface area of 300 to 3,000 m ² / g, preferably 500 to 500, by nitrogen adsorption under liquid nitrogen temperature conditions. 2,000 m ² / g. The pore volume is usually 0.1 to 2.0 ml / g, preferably 0.2 to 1.0 ml / g, and the average pore diameter is usually 0.1 to 3.5 nm, preferably 0. .5 to 3.0 nm.

The particle size of the activated clay is usually 0.01 to 15 mm, preferably 0.1 to 10 mm, and the activated clay has a BET specific surface area of 50 to 500 m ² / g, preferably 100 to 100, by nitrogen adsorption under liquid nitrogen temperature conditions. 350 m ² / g. The pore volume is usually 0.5 to 1.0 ml / g, preferably 0.6 to 0.8 ml / g, and the average pore diameter is usually 5.0 to 50.0 nm, preferably 8 0.0-30.0 nm.
The particle diameter of the zeolite is usually 0.01 to 15 mm, preferably 0.1 to 10 mm, and the zeolite has a BET specific surface area of 300 to 1,000 m ² / g by nitrogen adsorption under liquid nitrogen temperature conditions, preferably 400 to 750 m ² / g. The pore volume is usually 0.2 to 1.0 ml / g, preferably 0.4 to 0.6 ml / g, and the average pore diameter is usually 0.2 to 2.0 nm, preferably 0. .4 to 1.2 nm.
The particle diameter of the silica gel is usually 0.01 to 15 mm, preferably 0.1 to 10 mm. The silica gel has a BET specific surface area of 100 to 1,000 m ² / g by nitrogen adsorption under liquid nitrogen temperature conditions, preferably it is those of 300~800m ² / g. The pore volume is usually 0.1 to 1.5 ml / g, preferably 0.3 to 1.2 ml / g, and the average pore diameter is usually 0.5 to 20.0 nm, preferably 1 0.0-15.0 nm.
The particle diameter of the activated alumina is usually 0.01 to 15 mm, preferably 0.1 to 10 mm, and the activated alumina has a BET specific surface area of 50 to 500 m ² / g by nitrogen adsorption under liquid nitrogen temperature conditions, preferably 100 to 350 m ² / g. The pore volume is usually 0.1 to 1.0 ml / g, preferably 0.3 to 0.8 ml / g, and the average pore diameter is usually 1.0 to 15.0 nm, preferably 4 0.0-12.0 nm.

The shape of the porous carrier in the first adsorbent may be, for example, a powder shape, a crushed shape, a fiber shape, a cylindrical shape, a spherical shape, a honeycomb shape, or the like. When the shape of the porous carrier is a honeycomb, the number of cells is preferably 10 to 1,500 cells / inch ² , more preferably 25 to 750 cells / inch ² , and the thickness is preferably 5 mm or more / piece, more Preferably it is 7.5 mm or more / piece. Since the honeycomb having such a number of cells has a low airflow resistance, a plurality of these can be used in combination.

  Examples of the halogen carried on the porous carrier include bromine and iodine. Bromine is particularly preferable. As a method for supporting halogen on a porous carrier, when halogen is bromine, 1) vaporize bromine (99%) or a bromine-containing aqueous solution at room temperature and use a carrier gas such as nitrogen, A method of circulating contact with a porous carrier layer filled in a container, 2) A method of immersing the porous carrier in bromine or a bromine-containing aqueous solution at room temperature, and drying as necessary. 3) Using a sprayer or a sprayer A method in which liquid bromine or a bromine-containing aqueous solution is sprayed directly on a porous carrier at room temperature or sprayed with a carrier gas such as nitrogen and dried as necessary. 4) The bromine is left in a container together with the porous carrier, For example, when halogen is iodine, 1) Dissolve iodine in a solution such as alcohol at room temperature, immerse the porous carrier, and so on. 2) A method in which iodine is dissolved in an aqueous potassium iodide solution at room temperature and sprayed or sprayed onto a porous carrier using a sprayer or sprayer. 3) Iodine is left in a container together with the porous carrier. And vaporizing by heating to 100 ° C. and impregnation. The supported amount of halogen is usually 0.1 to 30% by weight, preferably 1 to 20% by weight, based on the weight of the porous carrier.

  The non-volatile acid supported on the porous carrier is an acid having a vapor pressure of 10 mmHg or less at 50 ° C., and examples thereof include inorganic acids such as sulfuric acid, phosphoric acid and boric acid, and organic acids such as oxalic acid and citric acid. However, sulfuric acid and phosphoric acid are preferable, and sulfuric acid is particularly preferable. As a method for supporting the non-volatile acid on the porous carrier, for example, 1) a method of immersing and drying the porous carrier in an aqueous acid solution at room temperature, and 2) a sprayer or sprayer for the aqueous acid solution on the porous carrier at room temperature There is a method of spraying directly with a carrier gas or spraying with a carrier gas such as nitrogen and drying. The amount of the non-volatile acid supported is usually 1 to 40% by weight, preferably 5 to 30% by weight, based on the weight of the porous carrier.

  Examples of the alkali metal of the alkali metal halide supported on the porous carrier include sodium, potassium, and lithium. Potassium is preferable, and examples of the halogen include bromine and iodine, and iodine is preferable. Specific examples of preferred alkali metal halides include, for example, potassium iodide and sodium iodide, and potassium iodide is particularly preferred. Examples of the method of supporting the alkali metal halide on the porous carrier include: 1) a method of immersing the porous carrier in an aqueous solution of an alkali metal halide at room temperature and drying; 2) alkali metal at room temperature on the porous carrier. Examples thereof include a method in which an aqueous solution of halide is directly sprayed using a sprayer or a sprayer or sprayed with a carrier gas such as nitrogen. The supported amount of alkali metal halide is usually 0.01 to 5% by weight, preferably 0.1 to 1% by weight, based on the weight of the porous carrier.

  The first adsorbent can be obtained by supporting a halogen, a non-volatile acid and an alkali metal halide on a porous carrier simultaneously or sequentially. At that time, the support of the halogen, non-volatile acid and alkali metal halide is supported. These may be performed in two or more simultaneously or sequentially in any order.

  In the present invention, the first adsorbent is preferably such that halogen, non-volatile acid and alkali metal halide are each uniformly supported on a porous carrier. Here, “homogeneous” means that when a sample of the adsorbent is arbitrarily extracted, the content of the support material in the sample is substantially equal. Uniformity cannot be achieved by combining or mixing porous carriers in which the supporting substances are individually supported, or in a mixture.

<Second adsorbent>
The second adsorbent used in the present invention is obtained by supporting a saturated cyclic secondary amine and an alkali metal or alkaline earth metal halide on a porous carrier.

  The porous carrier in the second adsorbent is composed of a porous adsorbing material similar to the porous adsorbent used in the porous carrier of the first adsorbent, and activated carbon is particularly preferably used. The preferred form and properties of the porous adsorbent material are basically the same as those in the porous carrier of the first adsorbent.

  As the saturated cyclic secondary amine, a 5-membered or 6-membered saturated cyclic secondary amine is preferably used. Examples of the 5-membered saturated cyclic secondary amine include pyrrolidine and thiazolidine. Examples of the 6-membered saturated cyclic secondary amine include piperidine, piperazine, N-methylpiperazine, morpholine, and thiomorpholine. Is used. Six-membered saturated cyclic secondary amines are preferable, and piperidine, piperazine, and morpholine are particularly preferable.

  Examples of the method for supporting the saturated cyclic secondary amine on the porous carrier include the following methods depending on whether or not the amine to be used is soluble in water. In the case of a saturated cyclic secondary amine soluble in water: 1) A method in which an amine is previously dissolved in water, and a porous carrier is immersed in this aqueous solution. 2) An aqueous solution of the compound is sprayed while stirring and mixing the porous carrier. Or, a method of spraying, 3) a method of mixing a powdery porous carrier and an aqueous solution of the amine, adding a binder as necessary, and granulating and molding. On the other hand, when using a saturated cyclic secondary amine that is insoluble in water, 4) a method in which a powdered porous carrier and a powdered amine are mixed in advance, and then granulated and molded by adding water and a binder; ) A method in which an amine and a binder are added to water to prepare a slurry in advance, and the slurry is sprayed or dispersed on a porous carrier and mixed. In the loading method, examples of the binder used as necessary include carboxymethyl cellulose, polyvinyl alcohol, arabic rubber, and the like. The addition amount (supported amount) of the saturated cyclic secondary amine to the porous carrier is usually 1 to 50% by weight, preferably 5 to 20% by weight, based on the weight of the porous carrier.

  Examples of the alkali metal forming the alkali metal or alkaline earth metal halide include lithium, sodium, potassium and the like, preferably potassium, and the alkaline earth metal includes magnesium, calcium and the like, Preferably it is calcium. Examples of the halogen include iodine and bromine, and iodine is preferable. Such alkali metal and alkaline earth metal halides are supported on the porous carrier in the same manner as the method for supporting the saturated cyclic secondary amine. The added amount (supported amount) of the halide to the porous carrier is usually 0.5 to 20% by weight, preferably 1 to 10% by weight, based on the weight of the porous carrier.

  Either a saturated cyclic secondary amine or a halide may be supported on the porous support first, or may be supported simultaneously.

  In the present invention, the second adsorbent is preferably such that a saturated cyclic secondary amine and an alkali metal or alkaline earth metal halide are each uniformly supported on a porous carrier. Here, “uniform” is synonymous with the above-mentioned “uniform”, and the uniformity cannot be achieved by combining or mixing porous carriers each carrying a carrier material alone.

<Contact treatment between adsorbent and gas to be treated>
In the present invention, (1) hydrogen sulfide and / or mercaptans (acid gas), (2) sulfides and / or disulfides (sulfur neutral gas), and (3) ammonia and / or amines (base) Gas) and (4) a gas to be treated containing at least a lower aldehyde is first brought into contact with the first adsorbent and then brought into contact with the second adsorbent. By performing the treatment in this order, an excellent deodorizing effect can be obtained. That is, when the gas to be treated (bad odor gas) containing the four kinds of malodorous components (1) to (4) is first contacted with the first adsorbent and then treated with the second adsorbent, As shown in Examples 1 and 2 to be described later, it is possible to deodorize the gas to be treated (bad odor gas) over a long period of time so that it becomes substantially odorless. As the lower aldehydes of (4), formaldehyde and acetaldehyde are typical, but propionaldehyde, acrolein, n-butyraldehyde, i-butyraldehyde, 3-methyl-butyraldehyde, crotonaldehyde and the like are also present. It can be deodorized by the deodorizing method of the invention. The first adsorbent and the second adsorbent may be used by being filled in separate processing tanks (columns), but the first adsorbent is filled on the gas inlet side of a single processing column, and the gas outlet side By using it as a cartridge filled with the second adsorbent, it can be easily applied to an existing deodorizing apparatus, and the deodorizing apparatus can be made compact.

  When the gas to be treated (bad odor gas) is first contacted with the second adsorbent and then processed in the order of contact with the first adsorbent, a good deodorizing effect is initially obtained as shown in Comparative Example 1 described later. Although it is obtained, the lower aldehyde gradually leaks without being removed by adsorption, and the treated gas becomes odorous. This is because when the second adsorbent is first brought into contact with the gas to be treated, the saturated cyclic secondary amine supported on the second adsorbent exhibits reactivity with sulfur-based neutral gases such as hydrogen sulfide and methyl mercaptan ( In other words, the saturated cyclic secondary amine in the second adsorbent is consumed by reaction with hydrogen sulfide or methyl mercaptan, and the saturated cyclic secondary amine is effective for the adsorption of lower aldehydes. It is considered that the lower aldehydes that do not function and are not adsorbed by the second adsorbent pass through the first adsorbent having a poor acetaldehyde adsorption function.

  In addition, when the treatment tank (column) is filled with only the second adsorbent and the gas treatment is performed only with the second adsorbent, sulfur-based neutral gas such as methyl sulfide or methyl disulfide is used as the second adsorbent. Contains no halogen to catalytically oxidize, so sulfur neutral gas leaks without being removed by adsorption, and non-volatile that can chemically adsorb basic gases such as ammonia and amines Since no acid is contained, the basic gas leaks without being removed by adsorption. On the other hand, when the treatment tank (column) is filled with only the first adsorbent and the gas treatment is performed only with the first adsorbent, the first adsorbent is a support for catalytically oxidizing lower aldehydes. Therefore, the lower aldehydes leak without being removed by adsorption.

In the present invention, the space velocity in the processing space of the processing gas (contact treatment with the adsorbent) is malodorous components concentration in the treated gas, varies depending on the shape or the like of the adsorbent, preferably 50～10,000Hr ^- It is about ¹ , More preferably, it is about 360-7,200hr < ^-1 >. The contact temperature is preferably −10 to 60 ° C., more preferably 0 to 50 ° C.

  The first and second adsorbents used in the present invention do not emit an irritating odor during drying or use, and the ignition point is not lowered even when the porous carrier is activated carbon. Therefore, the deodorization method of the present invention can be carried out in various facilities and places such as a water treatment plant, a sewage treatment plant, a human waste treatment plant, an incineration plant and the like, and since only two kinds of adsorbents are used, Can be implemented with existing facilities and equipment without any additional installation.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
Example 1
Adsorbent A (first adsorbent in the present invention)
4-6Mesh granular coconut shell activated carbon (4mm cylindrical coconut shell activated carbon with BET method specific surface area of 1150m ² / g, pore volume of 0.52mL / g, average pore diameter of 1.8nm) 10.0kg / batch Was added to the impregnation machine, and 0.40 kg of bromine was uniformly impregnated to obtain bromine-impregnated charcoal. Next, 0.02 kg of potassium iodide and 2.41 kg of 47% sulfuric acid were added to 1.72 kg of purified water and dissolved completely to prepare 4.13 kg of potassium iodide-sulfuric acid aqueous solution. Adsorbent A was obtained by uniformly spraying a potassium iodide-sulfuric acid aqueous solution in a shower-like manner while thoroughly stirring the bromine-impregnated carbon.
Adsorbent B (second adsorbent in the present invention)
To 1.00 kg of purified water, 0.2 kg of potassium iodide was added and completely dissolved to prepare 1.2 kg of an aqueous potassium iodide solution. 1.00 kg of morpholine was dissolved in an aqueous solution containing potassium iodide to obtain 2.20 kg of an aqueous morpholine-potassium iodide solution. Next, granular activated carbon of 4 to 6 mesh (4 mm cylindrical coconut shell activated carbon with a specific surface area by BET method of 1100 m ² / g, pore volume of 0.51 mL / g, and average pore diameter of 1.7 nm) 10.0 kg / 1 Adsorbent B was obtained by uniformly spraying a morpholine-potassium iodide aqueous solution in a shower-like manner while charging the batch into an adhering machine and stirring well.
A vinyl column of 10 cm diameter was packed with 2.4 L of adsorbent A on the gas inlet side and 2.4 L of adsorbent B on the gas outlet side. This column contains 25 ° C air (relative humidity 80%) containing 5 ppm hydrogen sulfide, 0.8 ppm methyl mercaptan, 2 ppm ammonia, 0.3 ppm trimethylamine, 0.18 ppm methyl sulfide, 0.02 ppm methyl disulfide, and 0.3 ppm acetaldehyde. m / sec. The gas odor at the outlet of the column was investigated and the leak component was determined by gas chromatography. The results are shown in Table 1.
The gas odor was investigated in accordance with the olfactory measurement method stipulated in the Odor Control Law.
That is, three bags are prepared, one bag is filled with the gas obtained from the column outlet, and the remaining two bags are filled with odorless air. Then, a panel of six persons hits a bag filled with the gas obtained from the column outlet from among the three bags prepared. All six panels judged that odor had leaked from the column outlet when the gas bag obtained from the gas outlet was applied (correct answer). At this time, the target leak component was determined according to the method for measuring a specific malodorous substance stipulated by the Malodor Prevention Law.

Example 2
Instead of the adsorbent B, 4-6 mesh granular activated carbon (BET specific surface area 1100 m ² / g) is uniformly loaded with 10% by weight of morpholine and 2% by weight of calcium bromide, and adsorbent B ′ (second adsorption in the present invention). In the same manner as in Example 1, the contact treatment with the adsorbent in the atmosphere was performed in the same manner as in Example 1 to investigate the column outlet gas odor and determine the leak component. The results are shown in Table 1.

Comparative Example 1
Adsorbent B is packed on the gas inlet side of the column, adsorbent A is packed on the gas outlet side of the column, and the rest is subjected to contact treatment with the adsorbent in the atmosphere in the same manner as in Example 1, and the column outlet gas odor And the leakage component was determined. The results are shown in Table 1.

Comparative Example 2
Adsorbent A and Adsorbent B are mixed in a uniform amount of 2.4 L each and packed into the column, and the rest is subjected to contact treatment with the adsorbent in the atmosphere in the same manner as in Example 1, and the column outlet gas odor Investigation and discrimination of leak components were performed. The results are shown in Table 1.

Comparative Example 3
Instead of the column filled with the adsorbent A and the adsorbent B, a column made of 4.8 L of the adsorbent B in a 10 cm diameter vinyl column (that is, the adsorbent B is present on both the gas inlet side and the gas outlet side). Except for using a packed column), the contact treatment with the atmospheric adsorbent was performed in the same manner as in Example 1, and the column outlet gas odor was investigated and the leak component was determined. The results are shown in Table 1.

Comparative Example 4
Instead of the column filled with the adsorbent A and the adsorbent B, a column made by packing 4.8 L of the adsorbent A into a vinyl chloride column having a diameter of 10 cm (that is, the adsorbent A is present on both the gas inlet side and the gas outlet side). Except for using a packed column), the contact treatment with the atmospheric adsorbent was performed in the same manner as in Example 1, and the column outlet gas odor was investigated and the leak component was determined. The results are shown in Table 1.

From Table 1, malodor containing hydrogen sulfide and / or mercaptans (acid gas), sulfides and / or disulfides (sulfur-based neutral gas), ammonia and / or amines (basic gas), and lower aldehydes The gas is first brought into contact with a first adsorbent (adsorbent A) in which a halogen, a non-volatile acid and an alkali metal halide are supported on a porous carrier, and then a saturated cyclic secondary amine and an alkali metal or alkaline earth. Deodorization is effectively performed only when the metal halide is contacted with the second adsorbent (adsorbents B and B ′) supported on the porous carrier and the excellent deodorizing performance is obtained. It can be seen that it is maintained for a long time.

Claims (3)

  A gas containing at least hydrogen sulfide and / or mercaptans, sulfides and / or disulfides, ammonia and / or amines, and lower aldehydes is first porous with halogen, non-volatile acid and alkali metal halide. Contacting with a first adsorbent supported on a carrier, and then contacting a saturated cyclic secondary amine and an alkali metal or alkaline earth metal halide with a second adsorbent supported on a porous carrier. Deodorizing method.   The deodorizing method according to claim 1, wherein the porous carriers of the first and second adsorbents are both activated carbon. The halogen in the first adsorbent is bromine, the non-volatile acid is sulfuric acid, the alkali metal halide is an alkali metal iodide, and the alkali metal or alkaline earth metal halide in the second adsorbent is an alkali metal or The deodorizing method according to claim 1, wherein the deodorizing method is an alkaline earth metal iodide.