JPH0455712B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a deodorizing agent, and particularly to a deodorizing agent for acidic and/or neutral malodors generated in manufacturing equipment, processing facilities, air conditioning equipment, and the like. (Prior Art) Offensive odors generated in manufacturing equipment, various processing facilities, air conditioning equipment, etc. of factories are considered as pollution along with water pollution, air pollution, noise, and the like. The odor control ingredients stipulated in the Offensive Odor Prevention Act are:
These eight substances, ammonia, hydrogen sulfide, trimethylamine, methyl mercaptan, methyl sulfide, methyl disulfide, acetaldehyde, and styrene, are substances that cause unpleasant odors and can harm the living environment. Regulatory values have been set for these components, and it is mandatory to prepare the environment so that the levels are below these values, but it is difficult to judge to what extent deodorization should be done, and it is difficult to determine the extent to which deodorization should be done. However, this does not mean that the odor problem has been solved. Moreover, odor is a pollution that directly appeals to human senses, and the generation of secondary pollution is also a problem, so various studies have been made to date on methods for removing it. In other words, known deodorizing methods include ozone oxidation, catalytic oxidation, direct combustion, and chlorine treatment, which oxidize and decompose malodorous components, as well as gas cleaning, adsorption, and ion exchange methods. ,
Each is selected and applied as appropriate, taking into account the substance that causes the odor and the location where the odor occurs. Among the above deodorizing methods, the adsorption method is generally applied because it is low in cost and easy to use. At this time, the adsorbent is
Activated carbon, silica gel, alumina gel, zeolite, etc. are used. However, when using these adsorbents to deodorize humid gas containing moisture, such as in the atmosphere, the moisture contained in the gas is adsorbed by the adsorbent, excluding activated carbon, resulting in deterioration of the adsorbent. This has the disadvantage that the adsorption of the target odor components of the gas is hindered. Therefore,
Deodorization methods using ion exchange methods and the like have been applied to wet gases, but these methods require large-scale equipment, ion exchange resins are expensive, and regeneration is labor intensive, resulting in high costs. Activated carbon has the property of selectively adsorbing other components even in the presence of water, and exhibits particularly effective adsorption properties for hydrophobic neutral substances with relatively large molecular weights. However, it has weak adsorption power for low-molecular-weight polar substances such as ammonia and hydrogen sulfide, and if a considerable amount of these substances is contained, effective deodorization will not be possible unless a large amount of activated carbon is used. It is difficult to expect any effects. Activated carbon also has the disadvantage that it is flammable and can be dangerous if used in large quantities. In order to improve the properties of activated carbon and deodorize gases containing acidic and alkaline components, impregnated activated carbon (hereinafter abbreviated as "impregnated carbon") is used.
is being developed. In other words, impregnated carbon is activated carbon that has been carefully selected or formed in advance, and a reactive liquid (acid, chlorine, catalyst component) corresponding to the malodorous component to be removed is placed in the spaces formed from the fine pores of the activated carbon. It is attached and held. In the case of impregnated carbon, the impregnated substance causes an irreversible chemical reaction with the malodorous components, converting the malodorous substance into an odorless substance, so its deodorizing ability is several tens of times that of ordinary activated carbon. It has good performance. However, even this method using impregnated carbon ultimately utilizes activated carbon, so when used in large quantities, it has the disadvantage of self-heating and ignition when the temperature rises slightly. (Problems to be Solved by the Invention) An object of the present invention is to provide a deodorizer for acidic and neutral malodors that is inexpensive, has good performance, and is highly safe, which solves the drawbacks of deodorizing malodors by the conventional methods described above. That's true. (Means for Solving the Problems) The present inventors focused on the latent hardening and alkalinity properties of granulated slag, which is obtained by rapidly cooling blast furnace slag discharged from blast furnaces in steel plants and making it fine. As a result of the development of a deodorizing technology in which an oxidizing agent is blended into the carrier, the product obtained by blending the oxidizing agent into the carrier and molding and curing is brought into contact with a foul-smelling gas to eliminate acidic odors. The present invention was completed based on the discovery that neutral malodors and the like can be effectively deodorized, and that the method is inexpensive and highly safe. That is, the gist of the present invention is a deodorizing agent for acidic and/or neutral malodors obtained by blending ferric oxide (Fe ₂ O ₃ ) as a hardening stimulant and oxidizing agent into a granulated slag carrier. . (Function) The present invention will be explained in detail below. In the present invention, granulated slag is used as a carrier for the deodorizing agent. This granulated slag is blast furnace slag (a molten product created by the reaction of impurities in iron ore, ash in coke, and limestone) that comes out of a blast furnace during iron manufacturing, and is composed of CaO, SiO ₂ , Al ₂ O ₃ , etc. ) out of
Basic slag with a weight ratio of CaO/SiO ₂ (basicity) of 1 or more is rapidly cooled with pressure water and made into fine particles. Generally, the granulated slag obtained by further pulverizing this granulated slag after drying and having an average particle size of about 9 to 10 μm is called ``fine powder'', but in this specification, this further pulverization is not performed, and the particles are Granulated slag with an average particle diameter of 2 mm or less, which has countless pores inside and outside, is called ``fine granules'' and is distinguished from the granulated slag. The chemical composition and properties of general granulated slag powder are shown in Tables 1 and 2. The fine particles also exhibit almost the same chemical composition and properties except for the average particle size.

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[Table] In the broadest sense, the present invention is not particularly limited to granulated slag, and the desired effect can be expected by using any granulated slag as a carrier. In a preferred embodiment of the present invention, fine powder and fine particles of granulated slag are used in an arbitrary proportion. It is particularly preferable to mix granulated slag fine powder: fine particles within the range of 7:2 to 3:6. In comparison with a deodorizer obtained by using only fine powder as a carrier without adding granulated slag fine particles, and adding a curing stimulant and an oxidizing agent (using Fe ₂ O ₃ ), the fine powder and fine particles were In the case of a deodorizing agent obtained by processing in the same manner except for using a carrier blended in the blending ratio, the deodorizing effect is significantly improved. If only fine water granulated slag powder with an average particle size of 9 to 10 μm is used as a carrier, it will be packed tightly when molded, but the particle size is relatively large and has numerous pores inside and outside. By incorporating particles, it is possible to obtain a molded carrier that maintains porosity and has a large reaction surface area, which probably improves the deodorizing effect and its sustainability. Granulated slag becomes glassy because blast furnace slag is rapidly cooled in water, and it is known that the higher the vitrification rate, the greater the latent hardening. Latent hardening is a property of granulated slag that is highly active and hardens by producing ^hydrates in the presence of an alkaline aqueous solution. This is due to the characteristic that it exhibits. That is, since granulated slag with a high vitrification rate has good hydration hardenability, it can be easily hardened by adding a hardening stimulant. An example of a setting stimulant is gypsum ( _CaSO4 .
Examples include cement materials such as 2H ₂ O), Portland cement, and blast furnace cement, and/or alkaline agents such as slaked lime and sodium hydroxide. The curing stimulant is usually pulverized into about 9 to 16 meshes. It is preferable to mix the carrier consisting of granulated slag fine powder and fine particles in a ratio of 9:1 by weight: the hardening stimulant. In the present invention, ferric oxide is used as the most preferable oxidizing agent for decomposing acidic and neutral components of malodors. The malodorous component removal performance of the oxidizing agent finally obtained is affected by the content of the oxidizing agent. In other words, if the content of ferric oxide is low,
Removal of malodorous substances takes time, and it may take several days to reach 100% removal. In addition, if the content exceeds a certain level, it will decrease to 100 in a short time.
% removal is possible, but in order to avoid wasting ferric oxide, its content should be between 0.2 and 5.0% relative to the total weight of granulated slag fines, fines, and curing stimulants.
% by weight, preferably 2.0 to 4.0% by weight. In addition, along with ferric oxide (γ-form Fe ₂ O ₃ ),
Hematite with a high Fe ₂ O ₃ content (α-form Fe ₂ O ₃ ) is also a preferred oxidizing agent in the present invention. in this case,
Hematite is added in a proportion of 0.2 to 5.0% by weight, preferably 3.0 to 4.0% by weight, based on the total weight of granulated slag fines, granules and hardening stimulant. In the present invention, Fe ₂ O ₃ is used as the oxidizing agent, which is preferable from an economical point of view because the used deodorizer can be easily reused as a soil conditioner. An appropriate amount of water is added to the mixture thus obtained, the mixture is kneaded and granulated, and then molded into a cylindrical shape with a diameter of, for example, 2 mm using an extruder, and cured at room temperature. As a molding method other than an extrusion molding machine, for example, it is possible to use a briquette machine, a pelletizer, a rolling granulator, etc. to form an almond shape, a sphere, or a pillow shape with a diameter of 1 to 10 mm. In order to easily manufacture items of this size,
A method by extrusion is preferred. The size and shape of this molded product is generally 2 to 3 mm in diameter.
mm is sufficient. Since the material itself is very porous and has sufficient contact surface area, there is no need to increase the contact area by changing the shape, but it can also be crushed to make the extrudate even finer. . When the deodorizing agent of the present invention thus obtained is brought into contact with acidic and/or neutral malodors, the acidic and neutral components in the malodorous gas are oxidized and decomposed by an oxidizing agent such as ferric oxide. and/or removed by adsorption and neutralization on an alkaline granulated slag carrier. When the deodorizer of the present invention is used, acidic malodors such as hydrogen sulfide and methyl mercaptan, and neutral malodors such as methyl sulfide and methyl disulfide, which are odor regulating components stipulated in the Offensive Odor Prevention Law, are particularly effectively removed. The present invention will be explained in more detail below by giving examples. The scope of the invention is not limited by the following examples. Example 1 Granulated slag fine powder with the property composition shown in Table 3, granulated granulated slag with the property composition similar to the property composition shown in Table 3 except for particle size (average particle size <2 mm), and property composition shown in Table 5 of slaked lime in a ratio (weight ratio) of 5:4:1, and 0.2% of ferric oxide with the property composition shown in Table 4.
~5% by weight was added and kneaded with an appropriate amount of water for about 5 minutes, then molded into a cylinder with a diameter of 2 mm using an extruder, hardened and dried at room temperature.

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[Table] In order to confirm the deodorizing ability of the obtained deodorizer against hydrogen sulfide (H ₂ S), an Erlenmeyer flask (capacity 3
) is filled with 500 ppm of H ₂ S gas, and this deodorizer 1
I put g. Additionally, a commercially available activated carbon deodorizer was placed in another Erlenmeyer flask containing H ₂ S gas. For each, the residual H ₂ S concentration over time was measured using a gas detection tube, and the removal rate was confirmed. As shown in Figure 1, the combination of 2 to 5% ferric oxide compared to a commercially available activated carbon deodorizer. It was found that both methods showed equivalent deodorizing effects and were able to remove 100% of H ₂ S in one hour. Example 2 Fine granulated slag powder having the property composition shown in Table 3, fine granulated granulated slag similar to the property composition shown in Table 3 except for the particle size (average particle size <2 mm), and ordinary commercially available Portland cement. :4:1 ratio (weight ratio)
After adding 0.5 to 5% by weight of hematite fine powder having the property composition shown in Table 6, adding an appropriate amount of water and kneading for about 5 minutes, using an extruder to form a powder with a diameter of 2 mm.
It was molded into a cylindrical shape, cured and dried at room temperature.

[Table] In order to confirm the deodorizing ability of the obtained deodorizer against hydrogen sulfide (H ₂ S), an Erlenmeyer flask (capacity 3
) is filled with 500 ppm of H ₂ S gas, and this deodorizer 1
I put g. Additionally, a commercially available activated carbon deodorizer was placed in another Erlenmeyer flask containing H ₂ S gas. For each, the residual H ₂ S concentration over time was measured using a gas detection tube, and the removal rate was confirmed. As shown in Figure 2, a mixture of 3 to 5% hematite was equivalent to a commercially available activated carbon deodorizer. It was found that the deodorizing effect was achieved, and 100% of H ₂ S could be removed in one hour. Example 3 In this example, blast furnace cement was used in place of the slaked lime used as the hardening stimulant in Example 1, and ferric oxide or hematite was added as the oxidizing agent, and the same procedure as in Examples 1 and 2 was carried out. When we prepared a deodorizer and checked the H ₂ S removal rate in the same way, the results were almost the same as in Figure 1 when the oxidizing agent was ferric oxide and in Figure 2 when the oxidizing agent was hematite. was gotten. (Effects of the Invention) As described above, the present invention skillfully takes advantage of the latent hardening properties, good heat resistance, and basicity of granulated slag, which is inevitably generated as a by-product in the steel manufacturing process. It is something to be used. The deodorizer of the present invention has a composition in which a curing stimulant is added to the granulated slag as a carrier, and an oxidizing agent such as ferric oxide is further blended to decompose acidic and neutral odors. , its deodorizing effect is remarkable. Furthermore, since the deodorizing agent of the present invention decomposes malodorous gas through a contact reaction between malodorous gas and an oxidizing agent, the deodorization of humid gas containing moisture in the atmosphere progresses quickly and its deodorizing effect lasts for a long time. It has excellent performance and lasts for a long time. Furthermore, the manufacturing cost is very low because granulated slag, which is produced in large quantities, is used. Furthermore, it is heat resistant, so there is no risk of it catching fire due to a slight rise in temperature, unlike activated carbon. Regarding the disposal of used deodorizers, the deodorizer of the present invention poses no problems at all from the perspective of pollution prevention, as granulated slag has been conventionally used in soil conditioners and silica fertilizers, and is suitable for industrial use. This is an effective method. As mentioned above, the present invention provides a deodorizing agent that solves the drawbacks of conventional deodorizing agents, and this type of deodorizing agent focuses on the characteristics of granulated slag and uses it as a carrier. This can be said to be an excellent usage with high added value.

[Brief explanation of drawings]

FIG. 1 is a graph showing the H ₂ S removal rate versus elapsed time when using the deodorizer of the present invention and a commercially available activated carbon deodorizer to which ferric oxide is added at various ratios as an oxidizing agent, and FIG. is a graph showing the H ₂ S removal rate versus elapsed time when using the deodorizer of the present invention and a commercially available activated carbon deodorizer to which hematite was added at various ratios as an oxidizing agent.

Claims (1)

[Claims] 1. A deodorizer for acidic and/or neutral malodors, characterized in that ferric oxide (Fe ₂ O ₃ ) as a curing stimulant and oxidizing agent is blended into a granulated slag carrier.