JP2003210930A - Deodorization method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently deodorizing the exhaust gas from a garbage treatment machine over a long period of time at a low running cost using a compact device. <P>SOLUTION: The exhaust gas from the garbage treatment machine is brought into contact with honeycomb activated carbon, especially chemicals supported honeycomb activated carbon at 50-150°C at a gas spatial velocity of 15,000/hr or more. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently deodorizing exhaust gas from a garbage processor at a low running cost for a long period of time.

[0002]

2. Description of the Related Art Exhaust gas from garbage processing equipment contains various odorous components such as hydrogen sulfide, sulfur-based compounds such as methyl mercaptan, nitrogen-containing compounds such as ammonia and amines, and aldehydes such as formalin and acetaldehyde. In addition, the concentration of odorous components, temperature, humidity, etc. change significantly over time, making deodorization difficult. Various methods such as a catalytic combustion method, an ozone deodorizing method, a chemical cleaning method, and a granular activated carbon adsorption method have been proposed as methods for deodorizing the exhaust gas from the garbage treatment machine. The catalytic combustion method uses exhaust gas in the presence of a catalyst of about 300
Although this is a method of heating to ℃, the running cost becomes high because the catalyst deteriorates. In the ozone deodorization method, it is necessary to adjust the amount of ozone in accordance with the type and concentration of odorous components contained in exhaust gas and to decompose unreacted ozone.
In the chemical cleaning method, a predetermined amount of chemical solution must be constantly supplied, and the chemical solution after cleaning must be treated. Since the granular activated carbon adsorption method has a low adsorption efficiency, a large amount of activated carbon must be used, the pressure loss is large, and gas drift is likely to occur. Moreover, dehumidification efficiency is further reduced with high-humidity gas such as exhaust gas from a garbage treatment machine, and there is a risk of heat generation and ignition due to contact with high-temperature gas. Both of these methods require a large deodorizing device and are difficult to maintain.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to use a compact device as a method for deodorizing exhaust gas from a garbage treatment machine, easy to maintain and maintain, low running cost, and good for a long period of time. The object of the present invention is to provide a method of exhibiting excellent deodorizing efficiency.

[0004]

Means for Solving the Problems As a result of various studies on the deodorizing method of the exhaust gas of the raw garbage treating machine, the present inventors have found that the exhaust gas of the raw garbage treating machine is applied to the honeycomb-like activated carbon layer at a high temperature and a high gas space velocity. The present invention has been completed by discovering that deodorization can be efficiently performed by contacting with. That is, the present invention provides (1) the exhaust gas from the garbage treatment device at a temperature of 50 to
Deodorizing method of contacting with honeycomb-shaped activated carbon at 150 ° C. and gas space velocity of 15,000 / hour or more, (2) Deodorization according to (1), wherein the number of cells of honeycomb-shaped activated carbon is 10 to 1,500 cells / inch ^2. Method (3) Honeycomb-shaped activated carbon B
(1) The deodorizing method according to (1), wherein the ET specific surface area is 200 m ² / g or more, and (4) the gas space velocity is 15,000 to 50.
The deodorizing method according to (1), which is 10,000 / hour, (5) the deodorizing method in which the honeycomb-shaped activated carbon is a chemical-supporting honeycomb-shaped activated carbon, and (6) the chemical supported on the honeycomb-shaped activated carbon is iodine or an inorganic iodide. , Bromine, inorganic bromide, acid, platinum group compound, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Ag compounds (5). ) The deodorizing method according to (1), wherein the honeycomb-like activated carbon whose deodorizing performance has deteriorated due to use is sprinkled with water, and the deodorizing treatment of the exhaust gas from the garbage treatment machine is performed again.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, exhaust gas from a garbage treatment machine is heated at a temperature of 50 to 150 ° C., preferably 60 to 150.
℃, gas space velocity 15,000 / hour or more, preferably 1
The honeycomb-like activated carbon is contacted at 5,000 to 500,000 / hour for deodorization. The linear velocity of the exhaust gas with respect to the honeycomb-shaped activated carbon is usually 0.3 to 10 m / sec. Preferably 0.5 to 7 m / sec. Is. Relatively high temperature by using honeycomb activated carbon under such conditions,
It can deodorize efficiently even at high humidity, high gas space velocity, and high linear flow velocity.

As the honeycomb-like activated carbon in the present invention, a known honeycomb-like activated carbon as described in, for example, Japanese Patent Publication No. 57-95816 can be used, and it is produced by the following method. In the first method, charcoal, which is a fine powder, coal, coke, sawdust, resin, and other raw materials are added with activators such as pitch, clay minerals and other binder alkali metal salts, and kneaded with water to form a honeycomb shape. Mold. After that, the honeycomb-like activated carbon used in the present invention is obtained by carbonizing and activating by a usual method.

The second manufacturing method is obtained by washing the honeycomb-shaped activated carbon obtained by the above-mentioned first manufacturing method with acid, water or the like, if necessary.

In the third method, charcoal, coal, coke,
Raw materials such as coconut husks and sawdust (if necessary, binder,
Add an activator and mold into a cylindrical or crushed shape. ) Is carbonized by a normal method, activated, washed with acid, water, etc. as needed, pulverized, and then a binder such as pitch and clay mineral is added and kneaded with water to form a honeycomb shape. It can be obtained by heat treatment if necessary. The honeycomb-like activated carbon used in the present invention can be obtained by these methods. In all of these, since the activated carbon is composed of fine particles instead of fibrous and has a honeycomb structure, it has a very dense structure and is most suitable for carrying out the present invention. The honeycomb-like activated carbon used in the present invention has an activated carbon content of 30.
% Or more, preferably 40% or more, and may contain various binders and porous clay minerals.

The number of cells of the honeycomb activated carbon used in the present invention is 10 to 1,500 cells / inch ² , preferably 50 to 1,000 cells / inch ² , and more preferably 100 to 750 cells / inch ² . is there. The opening ratio of the honeycomb is 50 to 80%, preferably 55 to 75%. The specific surface area of the honeycomb-shaped activated carbon is 200 m ²
/ G or more, preferably 300 to 3,500 m ² / g,
More preferably, it is 400 to 2,000 m ² / g.
Examples of odorous components generated from garbage processing equipment include sulfur-containing compounds (hydrogen sulfide, mercaptans such as methyl mercaptan, sulfides such as methyl chloride, disulfides such as methyl disulfide), and nitrogen-containing compounds (ammonia. , Dimethylamine, trimethylamine, triethylamine, etc.), aldehydes (formaldehyde, acetaldehyde, etc.), organic acids (formic acid, acetic acid, propionic acid, butyric acid, valeric acid, etc.) and the like. The gas to be treated usually contains at least one of these odorous components. The concentration of the odorous component is not particularly limited and may be, for example, about 0.1 to 1,000 ppm (volume basis).

One of the features of the present invention is that the exhaust gas from the garbage treatment machine is brought into contact with the honeycomb-shaped activated carbon at a temperature of 50 to 150 ° C. to deodorize. Usually, the temperature of the exhaust gas is gradually raised from room temperature, and finally 50 to 150 ° C, preferably 60 to 150 ° C, more preferably 80 to 130 ° C.
℃. With this change, the humidity also changes greatly, but by using the honeycomb-shaped activated carbon, the deodorizing performance can sufficiently follow even a large change in the gas properties.

In the present invention, the deodorizing performance can be sufficiently exerted even with the honeycomb-like activated carbon which does not carry chemicals, but the exhaust gas from the garbage disposer depending on the kind of garbage to be treated and the method of garbage disposal. Since the odorous components, temperature, humidity and the like in the inside fluctuate, it is possible to better cope with these treatments by using a honeycomb-shaped activated carbon carrying a chemical.

Among the chemical-supporting honeycomb-shaped activated carbons, the honeycomb-shaped activated carbons supporting iodine and inorganic iodide are obtained by supporting iodine or / and inorganic iodide on the honeycomb-shaped activated carbon. Inorganic iodides include I ₂ O ₅ , NH ₄ I, metal iodides, and the like. Examples of the metal iodide include LiI, NaI, NaIO ₃ , KI, KI ₃ , KIO ₃ , RbI and C.
alkali metal iodide such as _{sI; CaI 2, SrI 2,} BaI 2, MgI 2
Alkaline earth metal iodides; CuI, CuI ₂ , AgI, etc. Periodic table Ib group metal iodides; ZnI _2, etc. Periodic table
Group IIb metal iodides; AlI ₃ and other periodic tables Group III metal iodides such as CrI ₃ Periodic Table VI and group metal iodides;
MnI ₂ and other elements Periodic Table Group VII metal iodides; CoI ₂ , NiI
_The periodic table of elements such as ₂ includes iodide of Group VIII metal. Preferred inorganic iodides include I ₂ O ₅ , NH ₄ I, KIO ₃ ,
Alkali metal iodides, CoI ₂ , NiI ₂ , ZnI _{2 and the} like are included. Particularly preferable inorganic iodides are alkali metal iodides, and potassium iodide is particularly preferable. One type or two or more types of iodine and inorganic iodide can be used.

The loading of iodine or / and inorganic iodide on the honeycomb-shaped activated carbon can be carried out by a conventional method.
For example, iodine or / and inorganic iodide may be dissolved or dispersed in an organic solvent such as water or alcohol, and may be carried by being sprayed, impregnated or dipped in the above honeycomb-like activated carbon. Alternatively, iodine or / and an inorganic iodide may be kneaded as a raw material in the form of a solution or a fine powder, shaped, and supported. In the case of iodine, KI, NH
_It may be supported by being dissolved in an aqueous solution of ₄ I or the like and then sprayed, impregnated or dipped. Further, if necessary, iodine or / and inorganic iodide may be supported on the honeycomb-shaped activated carbon, and then dried or fired.

The amount of iodine or / and inorganic iodide supported on the honeycomb-like activated carbon can be selected within a range that does not impair the removal of odorous components.
It is 40% by weight, preferably 0.2 to 20% by weight, more preferably 0.4 to 10% by weight.

The bromine-supporting honeycomb-like activated carbon is obtained by spraying, impregnating or immersing liquid bromine or a solvent solution of bromide containing bromine on the honeycomb-like activated carbon, or by bringing gaseous bromine into contact with the honeycomb-like activated carbon. To be Examples of the bromide include hydrogen bromide, ammonium bromide, alkali metal bromide (eg, potassium bromide), and the like. As the solvent, water, alcohols (eg methanol, ethanol etc.), ketones (eg acetone etc.), ethers (eg diethyl ether etc.), halogenated hydrocarbons (eg chloroform, tetrachloride etc.) Carbon, ethylene chloride, etc.) and mixed solvents thereof are exemplified. The amount of bromine supported on the honeycomb-shaped activated carbon is 1 to 30% by weight, preferably 2 to 20% by weight, and particularly preferably 5 to 15% by weight.

The acid-supporting honeycomb-shaped activated carbon is obtained by supporting an acid on the honeycomb-shaped activated carbon. Examples of the acid include inorganic acids such as phosphoric acid, sulfuric acid and nitric acid, and organic acids such as oxalic acid, malonic acid, tartaric acid, succinic acid, citric acid, malic acid and glutaric acid. These acids can be used alone or in combination of two or more. Preferred acids include, for example, phosphoric acid, oxalic acid, malic acid and the like. More preferred acids include phosphoric acid. As phosphoric acid,
For example, orthophosphoric acid, metaphosphoric acid, polyphosphoric acid (chain polyphosphoric acid such as pyrophosphoric acid, cyclic polyphosphoric acid such as trimetaphosphoric acid and tetrametaphosphoric acid, infinite chain metaphosphoric acid, etc.)
And so on. Particularly preferred phosphoric acid includes orthophosphoric acid. Phosphoric acid may be used alone or in combination of two or more.

The supporting of the acid on the honeycomb-shaped activated carbon can also be carried out by a conventional method. For example, an acid may be dispersed, impregnated or immersed in the honeycomb-shaped activated carbon in the form of an aqueous solution or a dispersion to carry the acid. When manufacturing the honeycomb-shaped activated carbon, the acid alone or the aqueous acid solution, the dispersion is used as a raw material. It may be kneaded, molded, and supported. If necessary, the honeycomb-shaped activated carbon may be loaded with an acid and then dried or fired. The amount of acid supported on the honeycomb-like activated carbon is, for example, 0.1 to 60% by weight, preferably 0.2 to 50% by weight, and more preferably 5 to 40% by weight.

Examples of the platinum group element include platinum, iridium, osmium, palladium, rhodium and ruthenium. The loading amount of these platinum group element compounds on the honeycomb-shaped activated carbon is 0.01 to 2 as the platinum group element.
It is 0% by weight, preferably 0.025 to 15% by weight, particularly preferably 0.05 to 10% by weight.

The platinum-group element compound-supporting honeycomb-shaped activated carbon is sprayed, impregnated, and dipped into the honeycomb-shaped activated carbon with an aqueous solution of a platinum-group element compound such as hydrochloric acid, hydrogen iodide, hydrogen bromide, hydrofluoric acid, nitric acid, sulfuric acid, and phosphoric acid. It can also be obtained by kneading with a raw material in the form of an aqueous acid solution of these platinum group element compounds when manufacturing a honeycomb-shaped activated carbon. You may dry or bake as needed. The temperature at that time is 40 to 500 ° C., preferably 50.
To 400 ° C., particularly preferably 60 to 350 ° C., and the atmosphere at that time may be any of reduced pressure, normal pressure and increased pressure, and it can be carried out in the presence of air, nitrogen, carbon dioxide gas, combustion gas and the like. . Examples of the metal compound of Ti, V, Cr, Mn, Fe, Co, Ni, Cu or Ag include water-soluble inorganic salts of these metals, such as nitrates, sulfates and ammonium salts. These metal compound-supporting honeycomb-shaped activated carbons can be manufactured by the same method as the chemical-supporting honeycomb-shaped activated carbons supporting the platinum group element compound. In this case, the addition ratio of the metal compound is 0.5 to 15% by weight, preferably 1.0 to 10% by weight, as metal. The obtained metal compound may be dried or calcined if necessary. The temperature in that case is 40 to 500 ° C., preferably 50 to 400 ° C.,
The temperature is particularly preferably 60 to 350 ° C., and the atmosphere at that time may be any of reduced pressure, normal pressure, and increased pressure, and it can be performed in the presence of air, nitrogen, carbon dioxide gas, combustion gas, or the like.

In carrying out the present invention, the honeycomb-shaped activated carbon is laminated (filled) in a ventilated deodorizing device such as a deodorizing tower.
Can be used. The honeycomb-like activated carbon is laminated so that the gas flow direction and the ventilation holes (opening portions) of the honeycomb-like activated carbon are in the same direction. The honeycomb may be formed of one honeycomb or plural honeycombs. The plurality of honeycombs may be disposed in a longitudinal and / or lateral method along with the thickness direction as necessary. When a plurality of honeycombs are arranged in the thickness direction, the cells of adjacent honeycombs may be displaced from each other. According to the method of the present invention, therefore, while the deodorizing treatment is continued, the adsorption ability of the malodorous component of the honeycomb-like activated carbon gradually decreases. In that case, the adsorbing power of the activated carbon can be regenerated by sprinkling water on the honeycomb-like activated carbon. it can. That is, for example, while intermittently spraying water (water containing water and / or chemicals, etc.) on a packed bed of a deodorizing device equipped with an inlet for a treated gas and an outlet for a treated gas, the treated gas containing an odorous component (particularly, By aerating the air containing the odor component) and bringing the odor component into contact with the honeycomb-shaped activated carbon, it is possible to efficiently deodorize for a long period of time. The amount of water sprayed depends on the frequency of watering,
It is usually about 1/2 to 5 times the volume of the honeycomb-like activated carbon. Since the honeycomb-shaped activated carbon used in the present invention, particularly the chemical-supporting honeycomb-shaped activated carbon has a high gas adsorption capacity per unit volume, a compact device can be used.

[0021]

EXAMPLES The present invention will be specifically described with reference to the following examples. Example 1 Approximately 10 k of raw garbage including leftover food, scraps of vegetables, meat, fish, etc.
g was put in a garbage disposal and heated with an electric heater while blowing and stirring. The amount of exhaust gas from the processor is about 2.5-
It was 3.0 m ³ / min (converted at 25 ° C. and 1 atm). This exhaust gas was passed through a honeycomb activated carbon having a BET specific surface area of 900 m ² / g, a number of cells of 300 cells / inch ² , and a thickness of 30 mm to deodorize. At this time, the gas hourly space velocity for the honeycomb-shaped activated carbon layer was 100,000 to 120,000 / hour (calculated at 25 ° C. and 1 atmosphere). The temperature of the exhaust gas increased from 20 ° C. to 100 ° C. in 7 hours with the operation of the garbage processing machine. Meanwhile, as a result of evaluating the odor concentration of the inlet / outlet gas of the honeycomb-shaped activated carbon layer, the odor concentration of the column inlet gas changed from 100 to 1,000, but the odor concentration of the outlet gas was 50 or less. After the test was completed, about 3 kg of an odorless powdery dried product was obtained from the garbage processing machine.

Example 2 (1) Preparation of honeycomb-like activated carbon BET specific surface area 810 m ² / g, cell number 300 cells / in
A honeycomb-shaped activated carbon having a ch ² , an aperture ratio of 67%, a diameter of 27 mm and a thickness of 30 mm was designated as activated carbon A. 3.5 g of palladium chloride was dissolved in 100 ml of 4% nitric acid aqueous solution. A predetermined amount of this solution was added to the above-mentioned honeycomb-shaped activated carbon A with Pd-20.
The amounts of mg / g and HNO ₃ -40 mg were evenly dispersed and attached. This honeycomb-shaped activated carbon was heated to 140
It dried at 5 degreeC for 5 hours. During drying, most of HNO ₃ is decomposed and desorbed from the honeycomb-like activated carbon, and Pd-20 mg / g
A supported honeycomb activated carbon B was obtained. 3.5 g of palladium chloride, 14.8 g of copper nitrate hexahydrate and 1.1 g of phosphoric acid were dissolved in 100 ml of a 4% aqueous nitric acid solution. A predetermined amount of this solution was evenly dispersed on the above-mentioned honeycomb-shaped activated carbon A, and Pd-
20 mg / g, Cu-30 mg / g, HNO ₃ -40 m
g _{/ g,} the H 3 PO 4 -10mg / g were impregnated. This activated carbon was dried in air at 140 ° C. for 5 hours to obtain Pd-20 mg / g, Cu-30 mg / g, H ₃ PO ₄
-10 mg / g-supported honeycomb-like activated carbon C was obtained. (2) Deodorization Experiment 30 Kg of food residue from the restaurant was put in a garbage disposal and treated while blowing and stirring. With the operation of the processor, the temperature of the exhaust gas from the processor increased from 25 ° C to 130 ° C in 9 hours. Four columns having an inner diameter of 27 mm were prepared, and each of the honeycomb-shaped activated carbons A, B, and C prepared in (1) was laminated on a separate column for 90 mm, and one column did not contain the honeycomb-shaped activated carbon. The exhaust gas from the garbage treatment machine was supplied to the honeycomb-shaped activated carbon laminated columns A, B and C and the column not containing activated carbon at 50 liter / min (25 ° C., 1 atmospheric pressure conversion, linear flow rate of about 1. 5 m / sec, space velocity of about 60,000 / hour), and the deodorizing effect was observed. (3) Deodorization test result The outlet gas in each column was evaluated by the odor concentration, and the results are shown in Table 1.

[0023]

[Table 1] As apparent from Table 1, although there is sufficient deodorizing effect can honeycomb activated carbon A, deodorization performance by deodorization performance is improved by carrying Pd, supporting the Pd-Cu-H ₃ PO ₄ is further enhanced did.

[0024]

INDUSTRIAL APPLICABILITY The present invention uses a compact device as a deodorizing method from a garbage disposer, is easy to maintain and manage, has a low running cost, and has a high deodorizing effect for a long time. Not to mention, it can be conveniently used in general households.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4D002 AB02 BA03 CA07 DA41 GA01                       GB01 GB03 GB12                 4G066 AA05B BA07 BA24 BA26                       CA02 DA02                 4G146 AA06 AA15 AA16 AC07A                       AC08A AC08B AC09A AC10A                       AD32 BA01 BA11 BA38 BD08                       BD13

Claims (7)

[Claims] 1. The temperature of the exhaust gas from the garbage disposal is 50 to 1
A deodorizing method of contacting with honeycomb-like activated carbon at 50 ° C. and a gas space velocity of 15,000 / hour or more. 2. The number of cells of honeycomb-shaped activated carbon is 10 to 1,
The deodorizing method according to claim 1, wherein the number is 500 / inch ² . 3. The specific surface area of the honeycomb-shaped activated carbon is 200 m.
The deodorizing method according to claim 1, which is ² / g or more. 4. A gas space velocity of 15,000 to 500,0.
The deodorizing method according to claim 1, which is 00 / hour. 5. The deodorizing method according to claim 1, wherein the honeycomb-shaped activated carbon is a chemical-supporting honeycomb-shaped activated carbon. 6. The chemical supported on the honeycomb-shaped activated carbon is a compound of iodine, inorganic iodide, bromine, inorganic bromide, acid, platinum group compound, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Ag. The deodorizing method according to claim 5, wherein the deodorizing method is at least one selected from the group consisting of: 7. The deodorizing method according to claim 1, wherein the honeycomb-like activated carbon whose deodorizing performance has deteriorated due to use is sprinkled with water, and the deodorizing treatment of the exhaust gas from the garbage treating machine is carried out again.