KR101464994B1 - Catalyst support for Preparing a Catalyst for Removal of Nitrogen Oxides and method for Preparing thereof - Google Patents

Abstract

The present invention relates to a method for producing an alumina-based catalyst support which is appropriate for producing a selective catalytic reduction catalyst for removing nitrogen oxide by using discarded catalyst waste after high-cost catalyst active metal components are extracted (collected) from a waste catalyst discharged from a desulfurizing step in an oil refinery or the like. A support molded product, which is molded using molding clay produced by combining 20-50 parts by weight of zeolite with respect to 100 parts by weight of the catalyst waste, is dried and plasticized.

Description

Technical Field [0001] The present invention relates to a catalyst support for preparing a selective reduction catalyst for removing nitrogen oxides using catalyst wastes and a method for preparing the catalyst support,

The present invention relates to a catalyst support and a process for producing the same, and more particularly, to a catalyst support for the production of a selective reduction catalyst for nitrogen oxide removal using catalyst waste and a method for producing the same.

The selective reduction catalyst for removing nitrogen oxides is a denitration catalyst applied to a selective catalytic reduction reaction used together with a reducing agent to remove nitrogen oxides (NOx) contained in exhaust gases generated in automobiles, thermal power plants, chemical plants, etc., Oxides such as vanadium (V), tungsten (W), molybdenum (Mo), nickel (Ni), iron (Fe) and copper (Cu) are used. As the catalyst carrier, titania, alumina, (Silica) and zirconia (Zirconia) are mainly used. Since oxides such as vanadium (V), tungsten (W), molybdenum (Mo), and nickel (Ni), which are the main catalytically active components of the NOx removal catalyst applied to this selective catalytic reduction reaction, are expensive metals, There is a problem.

As a solution to the above problem, methods for recycling waste catalysts discharged from a desulfurization process of an oil refinery have been researched. As a recycling technique, a waste catalyst is treated under a certain condition to be suitable as a selective reduction catalyst for removing nitrogen oxides Technology and a technique for recovering expensive metals from waste catalysts discharged from the desulfurization process.

Typically, a selective reduction catalyst for removing nitrogen oxides is used by coating (supporting) an active ingredient on a honeycomb-shaped support. TiO ₂ (anatase) and cordierite are mainly used for the support, but TiO ₂ ) Has a considerable difficulty in drying during the production process, and cordierite is not only expensive but also high in weight and thus is considered to be unsuitable as a catalyst for supporting a denitration catalyst.

As a prior art related to a technology for recycling a waste catalyst discharged from a desulfurization process of the refinery to be suitable as a selective reduction catalyst for removing nitrogen oxides, for example, Korean Patent Registration No. 10-0584988 Among the alumina-based waste catalysts containing vanadium, nickel, molybdenum, iron, sulfur, silicon and the like, which are uneven in the component content discharged from the refinery in the desulfurization process, at least 10% by weight of vanadid, Providing a first raw material having a specific surface area of not more than 60 m < 2 > / g and a pore size of not less than 250 ANGSTROM, wherein the first raw material comprises not less than 5 wt% and not more than 3 wt% of molybdenum; Providing a second raw material having a specific surface area of not less than 130 m < 2 > / g and a pore size of not more than 150 ANGSTROM comprising vanadium of not more than 3 wt%, nickel of not more than 4 wt%, sulfur of not more than 2 wt%, and molybdenum of not less than 5 wt% ; Subjecting the first and second raw materials to a heat treatment at 300 to 400 ° C, respectively; Crushing each of the heat-treated raw materials to an average particle size of 100 to 200 mesh; Mixing the first raw material with an acid and water, and then adding a second raw material to the mixture; And drying the mixture at a temperature of 100 to 120 캜, followed by heat treatment at 450 to 550 캜 to remove nitrogen oxides. A method for producing a selective reduction catalyst for flue gas denitration using a spent catalyst is disclosed, No. 10-0439005 discloses a process for the preparation of an alumina support comprising the steps of: a) adding up to 4% vanadium, up to 4% nickel, at least 5% molybdenum, and less than 1% Treating the waste catalyst containing sulfur by heat treatment and washing with water to prepare a pretreatment; b) providing titania bearing 3 to 10 wt% tungsten on a titania basis; c) pulverizing the pretreated spent catalyst, uniformly mixing the tungsten-supported titania with water and an acid; d) dewatering the mixture to remove excess water and active metal components contained in the mixture; e) drying the dewatered mixture for at least 9 hours at a temperature in the range of from 100 to 200 < 0 > C and then shredding; And f) a step of extruding or coating the shredded mixture, and drying the shredded mixture after being dried under a constant temperature and humidity condition, and then firing the mixture. And a method for manufacturing a waste catalyst that is discharged from a desulfurization process and is suitably used as a selective reduction catalyst for removing nitrogen oxides is disclosed in Korean Patent Publication No. 10-0439004 and Korean Patent Registration No. 10-0382774 have.

As a prior art related to a technique for producing a support for a denitration catalyst, a titanium sulfate concentrate of 150 to 250 g / l based on TiO ₂ is added to a Korean Patent Registration No. 10-0641694, at a temperature of 90 to 120 ° C, and an anatase seed ) In an amount of 0.2 to 0.4% by weight; Dividing the mixture into 2 to 3 times so that the concentration becomes 100 to 120 g / l; And stirring the mixture at 30 to 60 rpm for 4 to 8 hours to induce grain growth; cooling and repeating washing with water and filtration twice; and a process for producing metatitanic acid for extrusion catalyst extrusion molding.

The molding aid is generally composed of known components to be added when preparing the catalyst support, and can be selected without difficulty by those skilled in the art. In the present invention, methyl cellulose, clay , And a lubricant is added if necessary, and 2 to 5% by weight of methyl cellulose and 8 to 15% by weight of clay are blended based on the total weight of the molding clay.

An object of the present invention is to provide a catalyst support for the production of a selective reduction catalyst for the removal of nitrogen oxides using catalyst wastes and a method for producing the catalyst support, and more particularly, After recovering (recovering) the catalytically active metal component, the catalyst waste that can not be recycled as a catalyst can be recycled to recover alumina suitable for the production of a selective reduction catalyst for nitrogen oxide removal, utilizing a small amount of active metal and alumina contained in the catalyst waste. And to provide a catalyst support prepared from the catalyst support.

The catalyst wastes according to the present invention can be obtained by extracting (recovering) components such as vanadium (V), molybdenum (Mo), and nickel (Ni), which are major active metals, from a spent catalyst discharged from a desulfurization process, Waste that can not be recycled and discarded. In the following, it is defined as 'catalyst waste'.

A method for preparing a catalyst support for the production of a selective reduction catalyst for removal of nitrogen oxides by using a catalyst waste is as follows. A raw material blending step of producing a molding blend by adding a molding aid and water to a support blend containing 20 to 50 parts by weight of zeolite per 100 parts by weight of catalyst wastes; b) forming a support molding Step and c). And a calcining step of drying the support molding and calcining at 500 to 600 ° C for 2 to 5 hours to produce a catalyst support.

In general, waste catalysts discharged from a refinery process are combined with nickel (Ni) and molybdenum (Mo), which are catalyst components, and vanadium (V), iron (Fe) It is a gamma-alumina-based waste catalyst containing sulfur (S). The content of major metal components is as shown in Table 1 below.

ingredient V ₂ O ₅ NiO MoO ₃ Fe ₂ O ₃ Al ₂ O ₃ Average content (% by weight) 20 12.0 5.0 0.9 50

A). The catalyst waste according to the raw material mixing step is composed of waste which can not be recycled as a catalyst after extracting (recovering) a major valuable metal component from a spent catalyst discharged from a desulfurization process in an oil refinery or the like, And alumina are as shown in Table 2 below, and the catalyst waste according to the present invention is prepared by pulverizing the catalyst waste to 200 mesh.

ingredient V ₂ O ₅ NiO MoO ₃ Fe ₂ O ₃ Al ₂ O ₃ Content (% by weight) 2.0 to 2.9 5.0 to 10.0 3.0 to 4.0 0.5 45 ~ 52

In the above a) zeolite selected from the raw material blending step is SiO ₂ / Al ₂ O to ₃ catalyst with a fine porosity of the material consisting of, and is widely used in the catalyst support, in the present invention, the specific surface area relative to the catalyst waste 100 parts by weight of (BET ) 20 to 50 parts by weight of zeolite of 120 to 150 m 2 / g, and the catalyst waste and the zeolite are preferably blended in a weight ratio of 80:20.

In addition, the molding clay according to the above a) mixing step is formed by kneading the raw material mixture while adjusting the amount of water to have a suitable fluidity according to the forming method of the support to form molding clay, 30 to 40% by weight based on the weight of the slurry. However, when the slurry is formed into clay, a larger amount of water can be added.

The molding aid is generally composed of known components to be added when preparing the catalyst support, and can be selected without difficulty by those skilled in the art. In the present invention, methyl cellulose, clay And 2 to 5% by weight of methylcellulose and a viscosity of 8 to 15% by weight based on the total weight of the molding clay are mixed with a lubricant if necessary.

B) according to the present invention. The support forming step is a step of forming a support having a desired shape from the molding clay obtained in the raw material blending step. The shape of the support according to the present invention may be formed by extruding the molding clay into a honeycomb structure, In the form of a slurry, and applying the slurry to both surfaces of the metal mesh to form a structure having a flat plate shape, a wrinkle shape, or the like.

The dimensions of the honeycomb structure, the flat plate, and the corrugated structure of the support to be formed according to the present invention are not particularly limited because they are to be manufactured according to the embodiment of the catalyst support, the use thereof, etc., and the metal mesh is made of stainless steel, A mesh network, an EX metal (expanded metal), or the like, and preferably an SUS metal mesh of the EX metal 3P to 4P standard is selected.

C) according to the invention. The calcining step is performed by drying a catalyst support formed into a predetermined shape in the support forming step and then calcining the catalyst support at 500 to 600 ° C for 4 to 5 hours to finally produce a catalyst support used for producing a selective reduction catalyst for removing nitrogen oxides .

(BET) of 60 to 75 m < 2 > / g, an average pore diameter of 9.74 nm, a total pore volume of 0.15 cm < 3 > / g , The adsorption force of the selective reduction catalyst component is excellent and the catalyst active component can be coated thinly. Therefore, the use amount of the catalytically active component is reduced, thereby reducing the cost required for manufacturing the catalyst.

Particularly, the alumina-based catalyst support produced by the production method of the present invention has the same coefficient of thermal expansion as that of the active components of the selective reduction catalyst and the metallic components remaining in the catalyst waste, It is possible to manufacture a catalyst that can be advantageously applied to a flue gas denitrification process because denitration does not cause the active metal to separate from the support and is excellent in denitrification effect at a low temperature.

The selective reduction catalyst for exhaust gas denitration produced from the catalyst support of the present invention is characterized in that the denitrification of the exhaust gas at a high temperature is accompanied by a phenomenon that the active metal is not separated from the support and the components of the desired coated It is advantageous in that the amount of the active component of the catalyst is reduced and the cost required for the catalyst production is reduced.

And exhibits an excellent denitrification effect at a low temperature, so that it is possible to produce a catalyst which can be advantageously applied to a flue gas denitrification process.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph comparing the denitrification effect at 220 to 500.degree. C. with respect to a selective reduction catalyst for exhaust gas denitration prepared with the catalyst support of the present invention. FIG.

Hereinafter, the present invention will be described in detail with reference to Examples and Test Examples. However, the present invention is not limited to the following examples.

The catalyst waste used in the embodiment of the present invention is a catalyst waste which is extracted and disused from the spent catalyst discharged from a desulfurization process in an oil refinery or the like [ SK Chemical Co., Ltd.], and the contents of the major components are as shown in Table 3 below.

ingredient V ₂ O ₅ NiO MoO ₃ Fe ₂ O ₃ Al ₂ O ₃ Content (% by weight average) 2.5 10 3.5 0.5 46

≪ Example 1 >

 20 kg of the waste shown in the above Table 3, 20 kg of zeolite (JAPAN, NAGOYA Nitrogen raw material Co., Ltd. name: H-3), 3 kg of methyl cellulose and 10 kg of kaolin clay were mixed with a combustion-free lubricant (JAPAN, NAGOYA Co Ltd, 3) and water were put into a conventional pressurized kneader (kneader) and kneaded to obtain molding clay.

The obtained clay was directly extruded by a screw extrusion molding machine to prepare a honeycomb formed body having a width of 150 mm, a length of 150 mm, a height of 150 mm, a thickness of a partition wall of 0.7 mm and a partition wall pitch of 4.0 mm, dried for 5 hours, Followed by time firing to prepare a support having a honeycomb structure.

The characteristics (compressive strength) of the honeycomb structure support and the honeycomb support (anatase support) used in the honeycomb structure according to the present invention were compared, and the results are shown in Table 4 below.

division Compressive strength (kgf / cm2) Sectional direction Lengthwise Example 1 [ 8 20 A commonly used support 4 12

≪ Example 2 >

 The mixture was blended in the same manner as in Example 1 to increase the water content to obtain clay in slurry form. Then, the surface of the metal mesh (15 cm x 15 cm) , Dried for 10 hours, and then calcined at 500 DEG C for 2 hours to prepare a flat catalyst support.

<Test Example>

For the comparative test on the denitrification effect of the selective reduction reaction (NH ₃ -SCR) of NO _X , the catalyst support (15 cm x 15 cm x 15 cm height) of the present invention was prepared by using the catalyst slurry for test A comparative catalyst prepared from a selective reduction catalyst for removing nitrogen oxide and a commercially available honeycomb support (anatase supporting agent, 15 cm x 15 cm x 15 cm high) was prepared.

a). Preparation of catalyst slurry for test

After the addition of 1000 g of titania, 22 g of ammonium metatungsten (AMT) and 44.0 g of ammonium metavanadmium (AMV), 65 g of organic acid (oxalic acid) having the same mol number as ammonium metavanadate was added, After milling, 5% of an inorganic binder was added and sufficiently ball-milled to prepare a coating slurry.

(Catalytic activity) of the catalyst was measured under the conditions of a space velocity of 10,000 / hr, 300 ppm of nitrogen monoxide (NO) and 300 ppm of ammonia, The catalyst activity was 90% or more at 450 ° C.

b). Preparation of selective reduction catalyst (SCR)

A space velocity of 10000 / hr, nitrogen monoxide (NO): 800 ppm, nitrogen monoxide / ammonia (NO / NO) were measured using a comparative catalyst made of a honeycomb support of the present invention, NH 3): 1, SO ₂ : 500 ppm, and 3% of oxygen at 220 ° C. to 500 ° C. The results are shown in FIG.

The catalyst (SCR) produced by the support of the present invention exhibits an excellent denitrification effect at a low temperature region (220 ° C, 250 ° C) as compared with the comparative catalyst, (SCR) can be produced at a low temperature as well as the advantage of recycling of waste since the present invention has no difference in denitrification effect as compared with the comparative catalyst. Therefore, Can be expected to be a very advantageous invention.

Claims (5)

(Recovered) at least one of vanadium (V), molybdenum (Mo) or nickel (Ni), which is a catalytically active metal component, from waste catalysts discharged from a refinery process in a refinery, A method for preparing a catalyst support for the production of a selective reduction catalyst for oxide removal,
a). 2 to 2.9 wt% of vanadium pentoxide (V ₂ O ₅ ), 5 to 10 wt% of nickel oxide (NiO), 3 to 4 wt% of molybdenum oxide (MoO ₃ ), 0.5 wt% of iron oxide (Fe ₂ O ₃ ) And 20 to 50 parts by weight of zeolite having a specific surface area (BET) of 120 to 150 m 2 / g are blended with 100 parts by weight of the catalyst waste containing 45 to 52% by weight of alumina (Al ₂ O ₃ ) A raw material mixing step for producing a molding clay,
b). A support forming step of forming the molding clay into a catalyst support, and
c). Drying the support molding, And calcining the catalyst support at 500 to 600 ° C for 2 to 5 hours to produce a catalyst support. The method for producing a catalyst support for the selective reduction catalyst for removing nitrogen oxides using catalyst wastes. The catalyst waste according to claim 1, wherein the catalyst support has a specific surface area (BET) of 60 to 75 m 2 / g, an average pore diameter of 9.74 nm and a total pore volume of 0.15 cm 3 / g. A method for preparing a catalyst support for the production of selective reduction catalysts. The method of claim 2, wherein the support body is a support body having a honeycomb, flat or corrugated structure. A catalyst support for producing a selective reduction catalyst for nitrogen oxide removal using a catalyst waste according to claim 3, wherein the support-molded product having a flat plate or corrugated structure is formed by coating a clay on both surfaces of the metal net. &Lt; / RTI &gt; A catalyst support for the production of a selective reduction catalyst for the removal of nitrogen oxides using catalyst wastes, which is produced by the production process according to any one of claims 1 to 4.

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