KR20030095912A - The catalyst for removing injuriousness gas and manufacturing method of the same - Google Patents

Abstract

PURPOSE: A preparation method of noxious gas removing catalyst is provided to maximize removing efficiency of noxious gases contained in flue gas by containing a reagent having high concentration in a supporter used as catalyst for purifying flue gas from various incinerators, and a noxious gas removing catalyst prepared by the method is provided. CONSTITUTION: The method comprises the steps of preparing a reagent for impregnating supporter by putting 1 to 30 weight parts of ammonium vanadate (NH4VO3), 1 to 60 weight parts of ammonium molybdate ((NH4)6Mo7O24·4H2O) and 1 to 30 weight parts of manganese acetate (Mn(CH3COO)2) into 400 weight parts of distilled water so that they are completely dissolved into the distilled water; absorbing the reagent into the supporter by impregnating the supporter into the reagent for 5 minutes after vacuuming the reagent to a pressure of 100 to 400 torr as maintaining the prepared supporter impregnating reagent in a warm bath having a temperature of 50 to 90 deg.C; and firing the supporter at a temperature of 400 to 500 deg.C for 5 hours by increasing temperature of the dried supporter at a rate of 100 deg.C/hr after completely drying the supporter in an oven of 120 deg.C by taking out the reagent impregnated supporter from the warm bath in the atmospheric pressure state after releasing the vacuum state.

Description

Catalyst for removing noxious gas and its manufacturing method {The catalyst for removing injuriousness gas and manufacturing method of the same}

The present invention relates to a catalyst for removing harmful gases and a method of manufacturing the same, and more particularly, to remove harmful gases such as dioxin, volatile organic compounds, nitrogen oxides and odorous gases generated in an incineration plant. It relates to a catalyst and a method for producing the same.

In general, the flue-gases generated by incineration of various wastes include various organic compounds harmful to the human body, such as polychlorinated dibenzo-p-dioxin, polydibenzofuran, polychlorinated biphenyl and benzene chloride, odor gas and nitrogen oxides. It contains a large amount.

In particular, the dioxin contained in the flue gas is generated during incomplete combustion of the incinerator, which is very toxic and highly carcinogenic, and since it does not decompose well in the natural environment, it has recently been used for the treatment and removal of flue gas generated during incineration. Many studies are in progress.

Currently, a method commonly used to treat flue-gases generated in an incinerator is to pass combustion flue gas through a catalyst bed at a temperature of 200 to 400 ° C. to oxidize dioxins, volatile organic compounds, nitrogen oxides or odorous substances contained in the flue gas. It is a method of decomposition and removal.

As the catalyst used in the oxidative decomposition method, metal oxides such as titanium (Ti), vanadium (V), tungsten (W), molybdenum (Mo), and chromium (Cr) are mainly used, and platinum (Pt) is used to increase the decomposition efficiency. ), Precious metals such as palladium (Pd), ruthenium (Ru), and rhodium (Rh) may be used together.

However, the noble metals not only have a high price of the catalyst, but also react with an acid such as hydrochloric acid, causing the catalyst activity to drop sharply, thus rapidly removing harmful gases such as dioxins, volatile organic compounds, nitrogen oxides, or odorous gases contained in the exhaust gas. In addition to the deterioration, there is a disadvantage that the performance of the catalyst is difficult to sustain for a certain period.

Accordingly, the present invention can maximize the removal efficiency of harmful gases such as dioxins, volatile organic compounds, nitrogen oxides or odorous gases contained in the exhaust gas by allowing the carrier used in the exhaust gas treatment of various incinerators to contain a high concentration of reagents. It is an object of the present invention to provide a method for preparing a catalyst for removing harmful gases.

It is another object of the present invention to provide a catalyst for removing harmful gas produced by the above production method.

The present invention to achieve the above object

1 to 30 parts by weight of ammonium vanadate (NH ₄ VO ₃ ), 1 to 60 parts by weight of ammonium molybdate ((NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O) and manganese acetate (Mn (CH ₃ COO) ₂ ) 1 to 30 parts by weight of distilled water is added to 400 parts by weight to completely dissolve a reagent for impregnating a carrier.

While maintaining the prepared carrier impregnation reagent in a hot bath of 50 ~ 90 ℃ to give a vacuum of 100 ~ 400torr, and impregnated the carrier to hold for 5 minutes to absorb the reagent in the carrier,

After releasing the vacuum and removing the carrier impregnated with the reagent at atmospheric pressure, and completely dried in an oven at 120 ℃, the dried carrier is heated at a rate of 100 ℃ / hr and calcined at 400 ~ 500 ℃ for 5 hours It provides a method for producing a catalyst for removing harmful gases.

In another aspect, the present invention provides a catalyst for removing harmful gas, characterized in that prepared by the above production method.

Hereinafter, the gas removing catalyst according to the present invention will be described in more detail through the preparation method as follows.

In the present invention, first, 1 to 30 parts by weight of ammonium vanadate (NH ₄ VO ₃ ), 1 to 60 parts by weight of ammonium molybdate ((NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O) and manganese acetate (Mn ( CH ₃ COO) ₂ ) 1 to 30 parts by weight of distilled water is added to 400 parts by weight and completely dissolved to prepare a carrier impregnation reagent.

The ammonium vanadate is converted into vanadium oxide during the firing process after being impregnated with the carrier. The vanadium oxide serves as a main catalyst for decomposing the organic compounds in the harmful gas contained in the exhaust gas. Therefore, when the amount of added ammonium vanadate is less than 1 part by weight, the amount absorbed in the carrier is low, and thus there is a disadvantage that the treatment efficiency of harmful gases is lowered. When the amount of added ammonium vanadate exceeds 30 parts by weight, undissolved ammonium vanadate is present. Since there is a disadvantage in increasing the manufacturing cost, the ammonium vanadate is preferably added 1 to 30 parts by weight.

Ammonium molybdate is converted to molybdenum oxide during the immersion process after the impregnation in the carrier, the molybdenum oxide serves as a promoter to help catalyze the vanadium oxide. Therefore, when the amount of added ammonium molybdate is less than 1 part by weight, there is a disadvantage in that the harmful gas removal efficiency is lowered due to insufficient help in catalysis of vanadium oxide, and when the amount of added ammonium molybdate exceeds 60 parts by weight. Since the content is too high to induce deactivation of the main catalyst to reduce the harmful gas removal efficiency, it is preferable to add ammonium molybdate within the above range.

In addition, manganese acetate is converted to manganese oxide during the sintering process after being impregnated with a carrier. Manganese oxide is excellent in oxidizing power even at low temperatures, thereby decomposing organic compounds well to enhance the removal efficiency of harmful gases. Therefore, if the addition amount of the manganese acetate is less than 1 part by weight, the sufficient effect is not obtained, and if the addition amount exceeds 30 parts by weight, undissolved manganese acetate is present, which increases the manufacturing cost. It is preferable to add 1-30 weight part.

When the ammonium vanadate, ammonium molybdate and manganese acetate in the above-mentioned range is added to and dissolved in distilled water, a reagent for impregnating the carrier can be prepared. The concentration of the reagent impregnated in the carrier can be controlled during impregnation and drying described below. It is not necessary to necessarily limit the amount of distilled water, but in the present invention, 400 parts by weight was used in consideration of the solubility of each additive and the content of the reagent absorbed in the carrier.

The carrier is impregnated with the carrier for impregnating the carrier so that the carrier is absorbed and dried. In the present invention, the carrier is impregnated with a vacuum of 100 to 400 torr while maintaining the reagent in a warm bath at 50 to 90 ° C. After holding for a minute to absorb the reagent in the carrier, the vacuum was released, the carrier impregnated with the reagent was taken out at atmospheric pressure, and dried sufficiently in an oven at 120 ° C. for complete drying.

In general, the method of impregnating a carrier in a reagent at room temperature and then removing it and drying it, such as a method of coating a catalyst on a honeycomb carrier, decreases the treatment efficiency of harmful gases contained in the exhaust gas due to the small amount of reagent absorbed in the carrier. In order to solve this problem, a sufficient amount of reagent is absorbed into the carrier by repeating the impregnation and drying processes several times.

In order to solve this problem, in the present invention, the carrier is impregnated with the reagent in a warm bath, and this process facilitates the penetration of the reagent into the pores of the carrier, and if the process is repeated several times, the reagent is uniformly infiltrated into almost all pores. do. However, since it is difficult to completely penetrate into all pores of the carrier with the impregnation reagent, in the present invention, the temperature of the impregnating reagent is raised and vacuum is applied. Thus, when the vacuum is applied, the air in the pores inside the carrier flows out. The impregnating reagent can be easily penetrated into the pores. Therefore, a high concentration of the reagent can be easily adsorbed to the carrier and at the same time a large amount of reagent is contained in the pores inside the carrier to maximize the treatment efficiency of harmful gases.

At this time, the warm bath may be carried out at various temperatures, but when the carrier is impregnated with the reagent in a low temperature warm bath, it is difficult to infiltrate the reagent to the pore velocity of the carrier, and the carrier may be dried by impregnating the carrier with the reagent in a high temperature hot bath. In this case, the working time will be faster but the reagent may boil over. In addition, the vacuum can be carried out under various conditions, but in a vacuum of less than 100 torr, the impregnating reagent is precipitated because the evaporation of moisture is too fast, whereas at 400 torr or more, the air in the pores of the carrier is not easily leaked. Therefore, in the present invention, the temperature of the impregnating reagent was adjusted to 50-90 ° C. and the reagent was deposited on the carrier while maintaining the vacuum at 100-400 torr, followed by drying.

In the process of impregnating the carrier with the reagent as described above, if the vacuum is applied at the same time while applying a vacuum, a large amount of the reagent is evenly absorbed to the inside of the pores to improve the treatment efficiency of the harmful gas contained in the exhaust gas. do.

In this case, various carriers may be used, including honeycomb carriers, which are generally widely used. In the present invention, 60 parts by weight of a conventional cordierite having Al ₂ O ₃ , SiO _2, and MgO as a main component A honeycomb carrier obtained by adding 10 parts by weight of clay, a small amount of polyvinyl alcohol (PVA) and water to obtain a slurry, and then extruding the slurry for 3 hours at 1300 ° C .; The urethane carrier obtained by coating the slurry on urethane foam and calcining at 1300 ° C. for 3 hours was mainly used.

The carrier impregnated under the above conditions is decompressed under vacuum and picked up under normal pressure, followed by drying in an oven at 120 ° C. for complete drying. At this time, if the impregnation and drying process is repeated 2 to 3 times, it is possible to maximize the content of the reagent impregnated in the carrier.

When the dried carrier is calcined, it is possible to prepare a catalyst for removing harmful gases according to the present invention. In the present invention, the catalyst is prepared by heating at 400 ° C / hr for 5 hours at a rate of 100 ° C / hr.

The produced catalyst for removing harmful gases contains a large amount of vanadium, molybdenum, and manganese oxides in the carrier, and thus the removal efficiency of harmful gases such as dioxins, volatile organic compounds, nitrogen oxides, and odorous gases contained in exhaust gases of various incinerators Can be maximized.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are only presented to aid the understanding of the present invention, but the present invention is not limited thereto.

<Production example of honeycomb carrier>

To 60 kg of conventional cordierite mainly composed of Al ₂ O ₃ , SiO _2, and MgO, 10 kg of clay, 500 g of PVA (polyvinyl alcohol) and distilled water were added and mixed, and then in a honeycomb form of 150 × 50 × 300 (mm). After injection, the injection molded product was dried at 120 ° C. for 2 days, and then calcined at 1300 ° C. for 3 hours to prepare a honeycomb carrier.

<Production example of urethane carrier>

To 60 kg of conventional cordierite mainly composed of Al ₂ O ₃ , SiO ₂ and MgO, 10 kg of clay, 500 g of PVA (polyvinyl alcohol) and distilled water were added and mixed, and then sprayed on urethane foam to 150 × 150 × 20 Prepared in (mm) size, the molded product was dried for 2 days at 120 ℃ and then fired for 3 hours at 1300 ℃ to prepare a urethane carrier.

<Example 1>

47 g of ammonium vanadate, 113 g of ammonium molybdate, and 37 g of manganese acetate were dissolved in 850 g of water to prepare a carrier impregnation reagent.The vessel containing the impregnation reagent was heated to maintain a temperature of 60 ° C. and a vacuum of 210 tor. After impregnating 3400 g of the honeycomb carrier of 150 × 50 × 300 (mm) prepared in the honeycomb carrier preparation example, the mixture was taken out and dried in an oven at 120 ° C. for 8 hours. After the impregnation and drying process was repeated two more times, the dried carrier was heated at a rate of 100 ° C./hr and calcined at 500 ° C. for 5 hours to prepare a catalyst for gas removal.

<Example 2>

42 g of ammonium vanadate, 108 g of ammonium molybdate, and 47 g of manganese acetate were dissolved in 850 g of water to prepare a carrier impregnation reagent. The vessel containing the impregnation reagent was heated to maintain a temperature of 60 ° C. and a vacuum of 210 tor. After impregnating 3400 g of the honeycomb carrier of 150 × 50 × 300 (mm) prepared in the honeycomb carrier production example, it was taken out and dried in an oven at 120 ° C. for 8 hours. After the impregnation and drying process was repeated two more times, the dried carrier was heated at a rate of 100 ° C./hr and calcined at 500 ° C. for 5 hours to prepare a catalyst for gas removal.

<Example 3>

44 g of ammonium vanadate, 115 g of ammonium molybdate, and 38 g of manganese acetate were dissolved in 850 g of water to prepare a carrier impregnation reagent.The vessel containing the impregnation reagent was heated to maintain a temperature of 60 ° C. and a vacuum of 210 tor. Then, impregnated with 3400 g of the urethane carrier of 150 × 50 × 20 (mm) prepared in the urethane carrier production example was taken out and dried in an oven at 120 ℃ for 8 hours. After the impregnation and drying process was repeated two more times, the dried carrier was heated at a rate of 100 ° C./hr and calcined at 500 ° C. for 5 hours to prepare a catalyst for gas removal.

<Example 4>

47 g of ammonium vanadate, 113 g of ammonium molybdate, and 37 g of manganese acetate were dissolved in 850 g of water to prepare a carrier impregnation reagent, and the vessel containing the impregnation reagent was kept at 25 ° C., and then the honeycomb carrier was added thereto. After impregnating 3400 g of the honeycomb carrier of 150 x 50 x 300 (mm) prepared in the preparation example, the mixture was taken out and dried in an oven at 120 ° C for 8 hours. After the impregnation and drying process was repeated nine more times, the dried carrier was heated at a rate of 100 ° C./hr and calcined at 500 ° C. for 5 hours to prepare a catalyst for gas removal.

Experimental Example 1

In order to determine the removal efficiency of dioxins, volatile organic compounds, nitrogen oxides and odors, a pilot plant having a size of 1/10 was installed in an exhaust port of an incinerator for incineration of paper sludge, and the catalysts prepared in Examples 1 to 4 were used. It was mounted on a pilot plant. The generated flue gas was passed through the catalyst at 300 ° C and a space velocity of 10000 / hr. At this time, the gas before and after the passage of the catalyst was collected, and the composition components and their components were analyzed using HRGC / MS, GC / ECD, GC / MS and gas analyzer. The concentration (dioxin: ng-TEQ / m ³ , volatile organic compound and odorous substance: ppm) was measured, respectively, and the removal rate was calculated. The results are shown in Table 1 below.

division Detection substance Before passing After passing Removal efficiency (%) Example 1 Dioxin 0.83 0.07 91,6 Volatile Organic Compounds a-Pinene 37 0.52 98.6 b-Pinene 19 0.13 99.3 Azulene 53 0.48 99.1 Nitrogen oxide NO _x 128 61 52.3 Odor substances Stylene 0.8 0.14 82.5 Meraptan 25 1.1 96 Example 2 Dioxin 0.68 0.08 88.2 Volatile Organic Compounds a-Pinene 43 0.94 97.8 b-Pinene 18 0.26 98.6 Azulene 73 1.21 98.3 Nitrogen oxide NO _x 115 63 45.2 Odor substances Stylene 0.8 0.19 76.3 Meraptan 24 1.7 92.9 Example 3 Dioxin 0.48 0.06 87.5 Volatile Organic Compounds a-Pinene 32 0.67 97.9 b-Pinene 24 0.17 99.3 Azulene 48 0.88 98.2 Nitrogen oxide NO _x 127 79 37.8 Odor substances Stylene 0.9 0.13 85.6 Meraptan 22 0.98 95.5 Example 4 Dioxin 0.92 0.43 53.3 Volatile Organic Compounds a-Pinene 42 5.76 86.3 b-Pinene 21 4.18 80.1 Azulene 64 10.7 83.3 Nitrogen oxide NO _x 108 87 19.4 Odor substances Stylene 1.3 0.3 76.9 Meraptan 19 1.6 91.6

As shown in Table 1, in Examples 1 to 3, the catalysts were prepared by impregnating the carrier in a warm bath and a vacuum state, then taking out and drying and calcining to remove the catalyst for harmful gases. Able to know. In particular, in the case of Examples 1 to 3, the removal efficiency of the catalyst is very high as compared to Example 4, in which the carrier is impregnated with a reagent at room temperature and atmospheric pressure and then taken out and dried, as in the general honeycomb catalyst production method. Able to know.

As described above, the present invention maximizes the removal efficiency of dioxins, volatile organic compounds, and odorous gases contained in exhaust gases of various incinerators, including urban waste and industrial waste incinerators, thereby dioxin, volatile organic compounds, and odor atmosphere. It is a useful invention to provide a catalyst for gas removal and a method of manufacturing the same that can minimize the discharge.

Claims (2)

1 to 30 parts by weight of ammonium vanadate (NH ₄ VO ₃ ), 1 to 60 parts by weight of ammonium molybdate ((NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O) and manganese acetate (Mn (CH ₃ COO) ₂ ) 1 to 30 parts by weight of distilled water is added to 400 parts by weight to completely dissolve a reagent for impregnating a carrier. While maintaining the prepared carrier impregnation reagent in a hot bath of 50 ~ 90 ℃ to give a vacuum of 100 ~ 400torr, and impregnated the carrier to hold for 5 minutes to absorb the reagent in the carrier, After releasing the vacuum and removing the carrier impregnated with the reagent at atmospheric pressure, and completely dried in an oven at 120 ℃, the dried carrier is heated at a rate of 100 ℃ / hr and calcined at 400 ~ 500 ℃ for 5 hours Method for producing a catalyst for removing harmful gas. Catalyst for removing harmful gases, characterized in that produced by the manufacturing method of claim 1.