KR20020027044A - Deodorant by using methylmercaptan removal catalyst and method of manufacturing the same - Google Patents

Abstract

PURPOSE: The deodorant of the present invention converts methyl mercaptan(CH3SH) generated from domestic refrigerators into water and dimethyl disulfide by reacting with oxygen. CONSTITUTION: The deodorant using methyl mercaptan removal catalyst is manufactured by kneading amorphous zeolite 20-40 wt.%, 10-20 wt.% of water glass as inorganic binder, 4-15 wt.% of methyl cellulose as organic binder, 5-15 wt.% of a reinforcing agent selected from rock wool, bentonite, and Ca(OH)2, 10-61 wt.% of molecular sieve 4A that is supported with at least one metal oxides selected from the group consisting of Fe, Cu, Ni, Mn, Zn, Co, Cr, Mg, and Ca; forming the kneaded raw materials into the shape of honeycomb; drying obtained honeycomb catalyst at the temperatures of 130-150°C while blowing steam; and dividing obtained deodorant at the temperatures of 400 to 500°C for 3-5 hours.

Description

Deodorant using methylmercaptan removal catalyst and method of manufacturing the same

The present invention is a molecular sieve for removing methyl mercaptan by oxidatively decomposing CH ₃ SH by reacting methyl mercaptan (hereinafter referred to as "CH ₃ SH") generated in a refrigerator with oxygen to convert water and dimethyl disulfide. It relates to a deodorant using the 4A supported catalyst and a method for producing the same.

Generally, a refrigerator that stores food stored at a low temperature by cooling it absorbs heat from adjacent air while the refrigerant compressed by the compressor evaporates from the cooler, thereby lowering the temperature, and cooling the cooled air according to the process. In order to prevent food deterioration or deterioration of freshness by keeping the food stored in the freezer compartment at low temperature by discharging it forward from the rear side of the freezer compartment and the refrigerating compartment according to the operation of the circulation fan provided on the back side. do.

Unlike the freezer, which stores food in a frozen state, the refrigerating chamber stores the food at a temperature higher than the freezing point. As a result of the use requirement, the food is stored for a long time, such as foods that have been cooked, or foods with strong odor such as kimchi and salted fish. When the odor generated during the storage of food is taken out every time the door is opened to take out food, the user and the people around him feel uncomfortable.

Therefore, the deodorant is provided in the refrigerating chamber of the refrigerator having a conventional structure to remove the odor generated during the storage of the food to eliminate discomfort to the user, and to prevent the infiltration of other food odors into the food stored therein. Keeps the inside of the house clean.

The deodorant for the refrigerator mainly has a function of removing methyl mercaptan generated from vegetables such as kimchi in the refrigerator.

The deodorant is composed mainly of a substance having excellent adsorption, such as activated carbon, and a metal oxide having a function as a catalyst.

Activated carbon, which is used as a carrier for the deodorant, is widely used as a carrier for deodorizing catalyst because of its excellent adsorption rate and wide surface area. However, performance decreases when contacted with air at a high temperature in the catalyst manufacturing process, and the process according to the preparation of the catalyst is considerably increased. There is a tricky problem.

In addition, activated carbon itself cannot be extruded in the form of honeycomb, which has a high strength and a large surface area of about 400 CPSI, and is usually formed through compression, so that the size of the cell is large and the cell is maintained for strength. There is no choice but to thicken the thickness between.

This wastes more activated carbon than necessary, and uses a binder such as polypropylene during compression, resulting in a reduction in surface area and performance degradation.

In addition, in the case of using a ceramic carrier without using activated carbon, there is no suitable carrier in Korea at present, and the catalyst manufacturer directly synthesizes the carrier.

In the case where the carrier used as a material of the deodorant for a refrigerator is directly synthesized and used, the manufacturing cost of the deodorant is increased and the process is also complicated.

Therefore, although researches on deodorants by commercially available ceramic carriers have been continued in many related companies, there has been no report on the development of catalysts by molecular sieve 4A in Korea, and since the molecular sieve 4A is a crystalline material, after molding, When the binder was removed, the bonding strength was weakened, the strength was not maintained, and the chipping phenomenon appeared, which was difficult to mold.

The present invention has been made to solve such a problem in the prior art, by preparing a supported catalyst with a molecular sieve 4A carrier sold in Korea, using the carrier having a strength of 400 CPSI and small cell size between cells Its purpose is to enable the formation of a deodorant that is thin but maintains strength and performance.

Another object of the present invention is to provide a deodorizing catalyst having good efficiency for removing CH ₃ SH by supporting metal oxide on molecular sieve 4A sold in Korea.

Another object of the present invention is to prepare a high-strength, high-performance honeycomb deodorant having a surface area of about 400 CPSI and not impeding the flow of cold air in a refrigerator by using a molecular sieve 4A supported catalyst having poor moldability.

According to an aspect of the present invention for achieving the above object, in the deodorizing agent for methyl mercaptan removal mainly used in the refrigerator, the molecular sieve 4A supported catalyst is 10 to 61% by weight of one or more metal oxides, amorphous zeolite 20 to 40% by weight of inorganic binder, 10 to 20% by weight of organic binder, 4 to 15% by weight of organic binder, and 5 to 15% by weight of reinforcing material, deodorant using methyl mercaptan removal supported catalyst is provided. do.

According to another aspect of the present invention, in the deodorizing agent for methyl mercaptan removal mainly used in refrigerators, 10 to 61% by weight of the molecular sieve 4A supported catalyst, at least one metal oxide, 20 to 40% by weight of amorphous zeolite, inorganic 10 to 20% by weight of the binder, 4 to 15% by weight of the organic binder, 5 to 15% by weight of the reinforcing material to obtain a raw material, molding the kneaded raw material, drying the molded deodorant, and dried There is provided a deodorant production method using a supported catalyst for methyl mercaptan removal, comprising the step of removing the organic binder contained in the raw material through a debinding process.

Hereinafter, the deodorant for a refrigerator according to the present invention and a method of manufacturing the same will be described in detail with the accompanying table.

The molecular sieve 4A supported catalyst used in the present invention is obtained by supporting a metal oxide on a commercialized molecular sieve 4A carrier.

As the metal oxide supported on the molecular sieve 4A carrier, at least one or more of Fe, Cu, Ni, Mn, Zn, Co, Cr, Mg, Ca, etc. may be used. It is supported by the impregnation method to prepare a supported catalyst.

The molecular sieve 4A itself has no activity, but has a surface area of about 400 m ² / g and has the advantage of improving the activity of the catalyst.

In the present invention, when the honeycomb deodorant is molded using the molecular sieve 4A supported catalyst, since the molecular sieve 4A is a crystalline ceramic and the bonding strength between the two is weak, in order to maintain the strength after molding, the molecular sieve 4A supported catalyst 10-61 It consists of 20% by weight, 20-40% by weight of amorphous zeolite, 10-20% by weight of inorganic binder, 4-15% by weight of organic binder, and 5-15% by weight of reinforcing material.

The organic binder is added at the time of kneading because the binding force is not formed due to the weak binding force of the molecular sieve 4A supported catalyst alone. However, if the organic binder remains in a state in which the preparation of the deodorant is completed, the organic binder has a fatal adverse effect on the performance of the deodorant and must be completely removed in the final process.

Accordingly, as the organic binder, methyl cellulose (MC), which is volatilized and blown off at a temperature of about 400 ° C. to 500 ° C. in a debinding step as a final step, is used. desirable.

If the amount of the organic binder is too small, the moldability is poor during extrusion of raw materials. On the contrary, if the amount is more than necessary, the strength of the molded product may not be maintained at the desired strength during the debinding process of removing the organic binder.

In addition, since the binding force of the molecular sieve 4A supported catalyst is weak, even if an organic binder is added during kneading of raw materials, an inorganic binder such as water glass is used so that the molded product does not crumble when the binder is subjected to the debinding process to remove the organic binder in the finished state. 20 weight% is added.

Reinforcing materials added to improve the strength and performance of the deodorant is any one of rock wool, bentonite, Ca (OH) ₂ , the strength of the deodorant when the addition amount of Ca (OH) ₂ 4 ~ 10% by weight And performance is further improved.

The deodorizing agent for methyl mercaptan removal is 10 to 61% by weight of a molecular sieve 4A supported catalyst having at least one metal oxide, 20 to 40% by weight of an amorphous zeolite, 10 to 20% by weight of an inorganic binder, and 4 to 15% by weight of an organic binder. 5-15 weight% of reinforcing materials are kneaded to obtain a raw material.

The raw material thus obtained is molded into a predetermined shape by using a molding machine. In an embodiment of the present invention, the cells are molded in a honeycomb shape so as to maintain strength and performance while having a small cell size and a thin thickness between the cells.

After molding the raw material to obtain a molded article, it is dried. The drying method of the molded article includes a steam drying method of drying by steam and a low temperature hot air drying method of drying by low temperature hot air.

The steam drying is a method of drying the molded product using water vapor heated to about 110 ~ 140 ℃ and low temperature hot air drying is hot air drying at a temperature of 130 ~ 150 ℃.

After drying the molding through the above-described process, the binder is subjected to a debinding process to remove the organic binder added to increase the bonding strength during molding.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

However, these are intended to explain the invention in more detail, but do not limit the scope of the invention.

Example 1 Comparison of CH ₃ SH Removal Rate of Molecular Sieve 4A Carrier

A relatively inexpensive molecular sieve 4A, which is commercially available in Korea, was purchased and the CH ₃ SH removal experiment was carried out without supporting the metal oxide.

Table 1 shows the percent CH ₃ SH removal of the molecular sieve 4A and the amorphous zeolite carrier.

As experimental conditions, the space velocity based on the bulk density of the catalyst in the reactor was maintained at 40,000 / hr, the concentration of CH ₃ SH was 200ppm and the remaining gas was injected with air.

Both carriers initially show adsorption removal rates but after 10 minutes the adsorption removal rates disappear.

Through this, it could be confirmed that both amorphous zeolite and molecular sieve 4A synthesized in the existing deodorant had only a slight adsorption and removal function but no function as a catalyst.

Therefore, the use of commercially available molecular sieve 4A is preferred to process difficult synthesis.

Comparative Example 1

An experiment was carried out by purchasing an amorphous zeolite which is a carrier of an already commercially available deodorizing catalyst.

carrier Reaction time (min) Specific surface area (m ² / g) 0 10 Example 1 Molecular Sieve 4A 100 0 450 Comparative Example 1 Amorphous zeolite 100 0 200

<Example 2, 3> Comparison of CH ₃ SH removal rate of the molecular sieve 4A supported catalyst

The supported metal catalyst was prepared by impregnating a metal oxide on the molecular sieve 4A, drying it at 120 ° C. for 12 hours in a drier, and calcining at 400 ° C. under an air atmosphere.

The supported catalyst prepared in this way is difficult to form due to its weak bonding force, so that the existing amorphous zeolite supported catalyst powder with strong binding force and the molecular sieve 4A supported catalyst powder are mixed in a 1: 1 ratio to form a catalyst ([Cu-Mn / molecular sieve). 4A] (50%) + [Cu-Mn / Amorphous Zeolite] (50%) was evaluated.

Experimental method was carried out in the same manner as in Example 1.

Table 2 shows the CH ₃ SH removal rate (%) of the molecular sieve 4A supported catalyst and the compatibilization catalyst.

The initial activity was lower than that of the commercially available catalyst (A) (B) for commercial use, but the molecular sieve 4A supported catalyst was found to be low, but in Example 3, the removal rate was maintained at about 30% for 200 minutes or more.

On the other hand, the catalyst for commercial use (A) for domestic sales supported on activated carbon disappeared after 100 minutes had elapsed.

The supported catalyst of the present invention is somewhat inferior in performance to that of the Japanese commercial catalyst (B), but there is no problem in removing a low concentration of CH ₃ SH from the refrigerator, and has a long service life.

Molecular sieve 4A itself was unable to maintain its strength during molding because of its low binding force, so the CH ₃ SH removal rate of the catalyst tested by mixing with an amorphous zeolite supported catalyst in a 1: 1 ratio was similar to that of the molecular sieve 4A supported catalyst.

<Comparative Example 2, 3>

The catalyst of Comparative Example 2 is a honeycomb type deodorizing catalyst product (A) made using activated carbon commercially available as a carrier, and Comparative Example 3 is a honeycomb type deodorizing catalyst product (B) using a ceramic carrier made in Japan.

catalyst Reaction time (min) 0 10 20 30 40 50 60 100 140 200 Example 2 Cu-Mn / Molecular Sieve 4A 100 87.5 65.8 41.9 40 30 28 23.9 23.9 22.6 Example 3 [Cu-Mn / Molecular Sieve 4A] (50%) + [Cu-Mn / Amorphous Zeolite] (50%) 100 67.2 36.2 28.9 - - - 28.5 - 28 Comparative Example 2 Commercialization catalyst (A) 100 100 92.8 83.8 55.2 37.2 30.4 0 0 0 Comparative Example 3 Commercialization catalyst (B) 100 100 100 100 100 100 100 67 43.5 38.4

<Examples 4 to 6> Effect of Calcination Temperature on Molecular Sieve Supported Catalyst 4A

The molecular sieve 4A supported catalyst was dried and calcined by changing the firing temperature to 350 ° C, 500 ° C, and 700 ° C in the firing process, and the CH ₃ SH removal rates of the catalysts were compared.

Table 3 shows the CH ₃ SH removal rate (%) according to the calcination temperature of the molecular sieve 4A supported catalyst.

When the firing temperature is 500 ℃, the initial activity was high, but after about 200 minutes, the CH ₃ SH removal performance was almost disappeared, and it was found that the performance was almost absent at 700 ℃.

On the other hand, when the calcination temperature is 350 ℃ it can be seen that the catalyst performance appears continuously.

Example Firing temperature (℃) Reaction time (min) 0 10 20 30 40 50 60 100 140 200 3 350 97 82.8 77.5 72.9 71.9 68.4 62.5 52.6 50 48.6 4 500 100 100 99.6 96.7 92 85.2 78.7 50.2 34.7 7.1 5 700 100 19.8 1.7 5.7 2.7 4.7 5.9 0 0 0

<Example 7,8> Comparison according to the drying method during molding

After adding various compositions to the molecular sieve 4A catalyst, the mixture is kneaded, molded into a honeycomb form, and then dried. The strength can vary greatly depending on the drying method, and the catalyst performance is greatly affected.

Table 4 compares the removal rate (%) of CH ₃ SH by the drying method of the honeycomb catalyst of the same composition by steam drying and low temperature hot air drying.

Steam drying is a method of injecting steam obtained by boiling water at 110 ° C. in a boiler using a boiler and drying it by steam for 2 hours. to be.

The molding appearance after drying was superior to the catalyst after low temperature hot air drying than the catalyst after steam drying, but the honeycomb after hot air drying caused a problem of cracking and brittleness.

In addition, in the performance comparison, the catalyst after steam drying showed continuous activity.

CH ₃ SH removal rate according to drying method after molding (%) Example Drying method Reaction time (min) 0 10 20 50 70 100 150 180 200 400 7 Steam drying 100 73 43.9 32.4 35.2 30.4 31.8 30.1 29.6 20.5 8 Low temperature hot air drying 100 95.6 48.8 35.7 33.5 29.2 25.7 24.6 16.5 0

<Example 9,10> Comparison according to the presence or absence of bentonite and rock wool

In order to enhance the strength of the catalyst, bentonite and rock wool were added in the form of reinforcing materials at 2 to 3% by weight, respectively.

Table 5 shows the CH ₃ SH removal rates of the catalysts.

When bentonite and rock wool were added, the strength was slightly improved, but the performance of the catalyst was markedly degraded.

For strength enhancement, instead of adding bentonite or rock wool, which is known as a material capable of increasing strength, it is desirable to increase the ratio of the existing amorphous zeolite supported catalyst, and to increase the amount of Ca (OH) ₂ as the inorganic binder water glass and the reinforcing material. Do.

The results are shown in Examples 11-13.

% Removal of CH ₃ SH with or without bentonite and rock wool Example Bentonite, rock wool Reaction time (min) 0 10 20 50 70 100 150 180 200 400 9 Unadded catalyst 100 73 43.9 32.4 35.2 30.4 31.8 30.1 29.6 20.5 10 Added catalyst 100 25.5 17.4 11.8 13.5 - - - - 0

<Examples 11-15> Comparison according to the change of molding composition

In order to maintain the performance of the catalyst and to enhance the strength of the honeycomb catalyst, the experiment was carried out through the change of the composition added during molding.

Table 6 shows a comparison of the compressive strength (kg _f / cm ² ) of the honeycomb catalyst according to the change (weight%) of the molding composition.

When molded with the molecular sieve 4A catalyst itself, the molding was hardly performed, and even when mixed with an existing amorphous zeolite-supported catalyst in a 1: 1 ratio, when water glass was not added, there was a problem of brittleness after molding.

After putting about 10% by weight of water glass with the inorganic binder, the compressive strength of the deodorant of 2 kg _f / cm ² or more was obtained.

As the ratio of the amorphous zeolite supported catalyst having good bonding strength increased, the compressive strength increased, and the compressive strength was improved when water glass, Ca (OH) ₂ , methyl cellulose, etc. were increased at an appropriate level.

At present, the basic specification of the compressive strength of the deodorizing catalyst for refrigerator is ² kg _f / cm ² after 10 seconds, which satisfies the case of Example 15, but the catalytic performances of Examples 11 to 14 are almost the same.

Comparison of Compressive Strength of Honeycomb Catalyst According to Changes in Molding Composition (wt%) (kg _f / cm ² ) Example Amorphous Zeolite Supported Catalyst Molecular sieve 4A supported catalyst water glass Ca (OH) ₂ MC Compressive strength 11 0 90 0 6 4 Molding (×) 12 45 45 0 6 4 Crumbs easily 13 40 40 10 6 4 2.3 14 30 50 10 6 4 1.3 15 42 22 16 12 8 2.7

<Example 16, 17> Comparison with or without debinding process

After debinding to remove the organic binder added in consideration of moldability in kneading after completion of drying of the molding in the honeycomb type deodorizing catalyst, the bonding strength of the honeycomb is weakened and the strength is lowered.

Example 16 relates to a honeycomb molecular sieve 4A catalyst with organic binder removed at 450 ° C. for 4 hours in a box-type furnace designed to be maintained in an oxygen-free nitrogen atmosphere in an electric furnace, and Example 17 is a catalyst without debinding. It is about.

Table 7 compares the CH ₃ SH removal rate and the compressive strength of the honeycomb type molecular sieve 4A catalyst before and after debinding.

If the debinding process is not performed, the strength remains higher than expected, but the activity of the catalyst is hardly seen after 10 minutes, and the performance of the catalyst is continuously maintained after the debinding process.

Comparison of CH ₃ SH removal rate (%) and compressive strength with and without debinding process Example Debinding Process Catalytic performance Compressive strength (kg _f / cm ² ) 16 U 20.5% removal after 400 minutes 2.7 17 radish 0% removal after 10 minutes 11.5

As described above, the present invention uses CH ₃ SH using inexpensive molecular sieve 4A, which is used commercially in Korea, instead of a ceramic carrier which is difficult to synthesize in activated carbon or a catalyst company, which is difficult to manufacture in the process used as a deodorant carrier. By simplifying the process of the supported catalyst by preparing a supported catalyst for the deodorant which can be removed at a high efficiency, the production cost of the deodorant is greatly reduced.

In addition, since it is a metal oxide catalyst using a crystalline ceramic carrier having durability and heat resistance, it is not only excellent in activity than the catalyst supported on activated carbon, but also has a long lifetime, and is used for removing odors at high temperatures as well as for low temperature to remove odors from a refrigerator. There is also an effect that can be applied to the catalyst.

Claims (15)

In the deodorizing agent for methyl mercaptan removal mainly used in refrigerators, the molecular sieve 4A supported catalyst carrying at least one metal oxide is 10 to 61% by weight, 20 to 40% by weight of amorphous zeolite, and 10 to 20 inorganic binder. A deodorant using a methyl mercaptan removal supported catalyst, characterized by consisting of 4% by weight and 4 to 15% by weight of an organic binder and 5 to 15% by weight of a reinforcing material. The method of claim 1, The metal oxide supported on the molecular sieve 4A is at least one of Fe, Cu, Ni, Mn, Zn, Co, Cr, Mg, and Ca. The deodorant using a methyl mercaptan removal supported catalyst. The method of claim 1, Deodorant using a supported catalyst for methyl mercaptan removal, characterized in that the organic binder is methyl cellulose. The method of claim 1, Deodorant using the supported catalyst for methyl mercaptan removal, characterized in that the inorganic binder is water glass. The method of claim 1, Deodorant using a supported catalyst for methyl mercaptan removal, characterized in that the reinforcing material is any one of rock wool, bentonite, Ca (OH) ₂ . In the deodorizing agent for methyl mercaptan removal mainly used in refrigerators, 10 to 61% by weight of a molecular sieve 4A supported catalyst, 20 to 40% by weight of amorphous zeolite, 10 to 20% by weight of inorganic binder, organic 4-15% by weight of the binder and 5-15% by weight of the reinforcing material are kneaded to obtain a raw material, molding the kneaded raw material, drying the molded deodorant, and debinding the dried deodorant. Method for producing a deodorant using a supported catalyst for removing methyl mercaptan, characterized in that it comprises the step of removing the organic binder contained in. The method of claim 6, Deodorant preparation using a supported catalyst for removing methyl mercaptans, characterized in that the supported catalyst is obtained by supporting any one or more metal oxides of Fe, Cu, Ni, Mn, Zn, Co, Cr, Mg, and Ca on the molecular sieve 4A. Way. The method of claim 6, Method for producing a deodorant using a supported catalyst for removing methyl mercaptan, characterized in that methyl cellulose is used as the organic binder. The method of claim 6, Deodorant production method using a supported catalyst for removing methyl mercaptan, characterized in that water glass is used as the inorganic binder. The method of claim 6, Deodorant production method using a supported catalyst for methyl mercaptan removal, characterized in that any one of rock wool, bentonite, Ca (OH) ₂ as the reinforcing material. The method of claim 6, A method for preparing a deodorant using a supported catalyst for removing methyl mercaptan, characterized by molding the kneaded raw material into a honeycomb shape. The method of claim 6, Deodorant production method using a supported catalyst for methyl mercaptan removal, characterized in that the drying by the steam heated to 110 ~ 140 ℃ in the drying step of the molded deodorant. The method of claim 6, Deodorant production method using a supported catalyst for methyl mercaptan removal, characterized in that the low-temperature hot air drying at a temperature of 130 ~ 150 ℃ in the drying step of the molded deodorant. The method of claim 6 or 8, 4-8 weight% of said organic binder is added, The manufacturing method of the deodorant using the supported catalyst for methyl mercaptan removal. The method of claim 6, Debinding process of the deodorant fired deodorant manufacturing method using a methyl mercaptan removal catalyst, characterized in that for 3 to 5 hours at 400 ~ 500 ℃.