WO2005063383A1

WO2005063383A1 - Catalyst including titanium dioxide and tin dioxide sorbed onto ceramic or metal carrier and method of producing same

Info

Publication number: WO2005063383A1
Application number: PCT/KR2004/003452
Authority: WO
Inventors: Seon-Mi Kim
Original assignee: Seon-Mi Kim
Priority date: 2003-12-30
Filing date: 2004-12-27
Publication date: 2005-07-14
Also published as: KR100769590B1; CN1929914A; KR20050070788A

Abstract

Disclosed is a catalyst, in which complex oxides of titanium dioxide and tin dioxide are sorbed onto a carrier including aluminum oxide so as to form a rutile structure, a method of producing the same, and a method of reacting pollutants using the catalyst after oxygen is removed from the pollutants. When treating mixed gas of carbon monoxide, sulfur oxide, and nitrogen oxide, sulfur dioxide and nitrogen oxide are respectively reduced into sulfur and nitrogen using carbon monoxide as a reducing agent. The catalyst converts mixed gas of nitrogen oxide and sulfur oxide, or any one component of the mixed gas into nitrogen and/or sulfur. Since it is unnecessary to install two devices in order to remove the two pollutants, installation costs are reduced. Catalytic activity is continued for a long time because exhaust gas smoothly passes through the catalyst without a load, thereby economically removing air pollution.

Description

Description CATALYST INCLUDING TITANIUM DIOXIDE AND TIN DIOXIDE SORBED ONTO CERAMIC OR METAL CARRIER AND METHOD OF PRODUCING SAME Technical Field

[1] The present invention relates to a catalyst for reducing pollutants, which include CO, SO , NO and the like and are generated by the petrochemical industry, the oil refining industry, the power generation industry, the incineration industry, boilers, or diesel engines, into nonpolluting materials of S and N . In the catalyst, complex oxides 2 of titanium dioxide and tin dioxide are applied on an aluminum oxide carrier so as to form a rutile structure. Furthermore, the present invention pertains to a method of producing the catalyst and a method of reducing pollutants using the catalyst to remove the pollutants. Background Art [2] Conventionally, mixed gas of carbon monoxide, nitrogen oxide, and sulfur oxide is converted into nonpolluting materials using large-scale devices in such a way that CO is oxidized into CO , and NO and SO are neutralized through a chemical reaction. 2 x x Recently, a technology, in which titanium dioxide and tin dioxide are mixed in an aqueous solution to produce a catalyst having a rutile structure, and in which nitrogen oxide and sulfur oxide are respectively reduced into nitrogen and sulfur in the presence of the catalyst using carbon monoxide as a converting agent, has been suggested. However, since tin dioxide and titanium dioxide are mixed in the aqueous solution to produce the rutile structure in a form of sand, if the catalyst is used while being packed in a container, a load significantly increases when waste gas passes through the container.

[3] In other conventional technologies, pollutants are removed using different devices and catalysts according to the type of pollutant.

[4] However, the conventional technologies are disadvantageous in that since the devices are installed separately, they are economically inefficient. Additionally, a process of removing the above polluting mixture using an alloy of titanium dioxide and tin dioxide has been developed. However, active components do not infiltrate into a carrier, and are nonuniformly attached to a surface of the carrier. Even though the active components are well attached to the surface, since the active components are readily separated from the carrier, a catalyst cannot be used for a long time and thus cannot be commercialized. [5] As well, a patent has been made by the inventor of the present invention. The patent discloses a catalyst and a method of producing the same, in which titanium dioxide and tin dioxide are bonded to an internal side and a surface of ceramic; containing silicon oxide and aluminum oxide, as a carrier to produce a catalyst having a rutile structure. However, in the catalyst produced through the patent, mullite is used as a component of the carrier, significantly limiting the activity of the catalyst, resulting in reduced conversion efficiency of NO and SO into S and N. Disclosure of Invention Technical Problem

[6] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a catalyst, which removes mixed gas of carbon monoxide, nitrogen oxide, and sulfur oxide and in which titanium dioxide and tin dioxide as active components are uniformly and firmly sorbed onto an internal side and a surface of a carrier, containing aluminum oxide (alumina), to produce the catalyst having a rutile structure, and a method of producing the same.

[7] Another object of the present invention is to provide a method of producing a catalyst, and the catalyst as a product produced using the same. In the method, aluminum oxide is applied to a surface of a carrier having a predetermined shape, which consists of materials according to a typical technology, and titanium dioxide and tin dioxide are sorbed onto aluminum oxide so as to form a rutile structure.

[8] A further object of the present invention is to provide a method of producing a catalyst, in which soluble salts of titanium dioxide and tin dioxide are mixed and precipitated in an aqueous solution state to produce rutile in a form of sand and rutile is compacted in various shapes using aluminum oxide as a binder to produce the catalyst, and the catalyst as a product of the method.

[9] Yet another object of the present invention is to provide a method of producing a catalyst, in which soluble salts of titanium dioxide and tin dioxide are dissolved in water to produce an aqueous solution, and the aqueous solution is mixed with aluminum oxide to produce the catalyst containing a carrier capable of having various shapes, and the catalyst as a product of the method.

[10] Still another object of the present invention is to provide a method of converting pollutants, including CO, NO , and SO , into S and N using the catalyst of the present invention, in which oxygen is removed from the pollutants to improve the activity of the catalyst of the present invention. Technical Solution

[11] In order to accomplish the above objects, the present invention provides a catalyst for simultaneously removing carbon monoxide, nitrogen oxide, and sulfur oxide. The catalyst comprises a carrier, which includes highly pure aluminum oxide (alumina), and metal complex oxide as an active component, which is sorbed onto the carrier and which includes rutile (TiO ) containing 20 - 80 wt% titanium dioxide (TiO ) and 20 - 2 2 80 wt% tin dioxide (SnO ). 2 Advantageous Effects

[12] As described above, a method of producing a catalyst and the catalyst produced using the method according to the present invention are advantageous in that carbon monoxide, sulfur oxide, and nitrogen oxide are simultaneously removed using the catalyst, and costs of installation and maintenance are significantly reduced. Best Mode

[13] A catalyst of the present invention is produced through the following four methods.

[14] (1) Highly pure alumina powder, activated carbon or polymer powder as a supplemental agent, and a binder (carboximethyl cellulose, and polyvinyl alcohol) are mixed with each other, and compacted in various typical sphere, tube, hone _omb, ring, rod, fine spherical grain, plate, or seed shapes. The resulting structure is sintered at high temperatures to produce a carrier as a supporter of an active component.

[15] The amount of the supplemental agent is 1 - 20 % based on the total weight of aluminum oxide, and the amount of the binder is 1 - 10 % based on the total weight of aluminum oxide.

[16] A sintering temperature is 1000 - 1500 °C , and the sintering is conducted for 1 - 15 hours.

[17] 20 - 80 % titanium sulfate (Ti (SO ) ) of titanium dioxide (TiO ) and 20 - 80 % tin 2 4 2 2 chloride (SnCl , SnCl ? 5H O) of tin dioxide (SnO ) are dissolved in anion-free water 4 4 2 2 to produce an aqueous solution. [18] Water is electrolyzed to produce anion-free cationic water, and ammonia water (NH ) is mixed with the aqueous solution. Citric acid is dissolved in the anion-free 3 water, and the citric acid solution is mixed with the resulting aqueous solution to produce a mixed aqueous solution. [19] Even if citric acid is not added, no effect is applied to the performance of a catalyst if the mixed aqueous solution is uniformly applied on an internal side and a surface of the carrier. [20] The carrier is put in a container, and the container is vacuumized to remove impurities and air from the pores of the carrier. Subsequently, the mixed aqueous solution is injected into the vacuumized container. After the mixed aqueous solution is injected into the container in a vacuum, precipitation is conducted for 1 - 2 hours at atmospheric pressure.

[21] With respect to this, it is noted that the pH of the mixed solution must be 7 - 8.

[22] The carrier immersed in the mixed solution is then washed with cationic water. In 2- this regard, the washing is continued until chlorine ions (Cl ) and sulfate ions (SO ) 4 are not detected in the washing water. [23] The washed precipitate is dried at 90 - 150 °C for 10 - 20 hours, and indirectly heated at 400 - 700 °C for 2 - 5 hours to produce the carrier. Titanium dioxide (TiO ), 2 which is infiltrated into and attached to the carrier, and tin dioxide (SnO ) form a 2 tetragonal system rutile (TiO ) structure, thereby creating the catalyst using sorption. A 2 composition of tin dioxide (SnO ) and titanium dioxide (TiO ) of the catalyst thusly 2 2 created is 2 - 8 : 2 - 8 by weight.

[24] (2) A mixture of alumina and silica, codierite, ceramic; a mixture of magnesium oxide and alumina, a mixture of magnesium oxide and silica, a mixture of alumina and zirconia, kaolin powder, yellow earth powder, elvan powder, or mixed powder of kaolin, yellow earth, and elvan is mixed with activated carbon, as a supplemental agent, and a binder, to produce a carrier in the shape of a sphere, tube, hone _omb, ring, cylinder, rod, fine spherical grain, plate, or seed. Alternatively, zeolite, silicon carbide, or carbon powder is mixed with activated carbon so as to have high porosity, mixed with a binder, and compacted into the above shapes to produce a carrier. The carrier as described above, or a carrier produced through a typical technology is immersed in an aqueous alumina solution, and sintered, thereby creating the carrier having alumina sorbed in a thickness of 0.2 - 3 mm onto an internal side and a surface thereof.

[25] The sorption of titanium dioxide and tin dioxide onto the resulting carrier so as to form a rutile structure is conducted through the same procedure as the method (1), thereby creating a catalyst as a product.

[26] (3) A catalyst is produced through the following alternative method.

[27] Titanium sulfate of titanium dioxide and tin chloride of tin dioxide are separately dissolved in cationic water at a weight ratio of 2 - 8 : 2 - 8, and the two solutions are mixed with each other. Ammonia is mixed with cationic water, and ammonia water was mixed with the two solutions. [28] After a predetermined time, precipitate is extracted from the mixed solution, and then washed using cationic water through the same procedure as the above methods until chlorine ions and sulfate ions are not detected. Subsequently, the washed precipitate is dried at 90 - 120 °C for 1 - 10 hours, and sintered at 400 - 700 °C for 2 - 5 hours to produce the resulting precipitate. The resulting precipitate has a specific 2 -1 surface area of 95 - 120 m g and a rutile structure.

[29] The resulting precipitate, that is, rutile, is mixed with highly pure alumina powder in a ratio of 6 - 9 (rutile) : 1 - 4 (alumina), compacted in various shapes, and sintered at 350 - 700 °C for 2 - 5 hours to produce the catalyst as a product.

[30] (4) 20 - 80 wt% titanium sulfate and 20 - 80 wt% tin chloride are mixed with each other to produce a mixed aqueous solution, or alternatively, they are separately dissolved in cationic water to produce different aqueous solutions and the aqueous solutions are then mixed with each other in the above ratio to produce the mixed aqueous solution.

[31] Highly pure alumina powder is mixed with the mixed aqueous solution in an amount of 10 - 50 % based on the weight of titanium dioxide and tin dioxide contained in the mixed aqueous solution, and then mixed with a predetermined amount of ammonia water. The resulting mixture is compacted in various shapes, washed with cationic water until sulfate ions and chlorine ions are not detected, dried at 90 - 150 °C for 1 - 10 hours, and sintered at 300 - 700 °C for 2 - 5 hours to produce a catalyst as a product.

[32] The catalyst produced aooording to the present invention as described above converts sulfur oxide and nitrogen oxide into S and N , respectively, with an efficiency 2 of 95 - 100 %, using carbon monoxide as a reducing agent.

[33] It is noted that the activity of the catalyst of the present invention is reduced or exhausted in the presence of oxygen. If oxygen is mixed with pollutants of carbon monoxide, nitrogen oxide, and sulfur oxide, it is necessary to allow the pollutants to react in the presence of the catalyst after oxygen is separated through the following procedure.

[34] A plurality of containers is installed to enable the pollutants to flow therethrough. After the pollutants containing oxygen are fed into a first container, methane (CH ) is 4 fed thereinto to separate oxygen from the pollutants, and separated oxygen is fed into a second container and then exhausted. The pollutants as the remaining material are fed into the other second container, in which a catalyst is packed, to react in the presence of the catalyst. Mode for Invention

[35] A better understanding of the present invention may be obtained through the following examples which are set forth to illustrate, but are not to be construed as the limit of the present invention.

[36] EXAMPLE 1

[37] Highly pure alumina powder was mixed with a supplemental agent which was selected from polymer powder or activated carbon powder, and the mixture was mixed with a binder and then compacted in a sphere, tube, hone _omb, ring, cylinder, rod, plate, fine spherical grain, or seed shape to produce a carrier.

[38] Alternatively, a mixture of alumina and silica, codierite, ceramic; a mixture of magnesium oxide and alumina, a mixture of magnesium oxide and silica, a mixture of alumina and zirconia, kaolin powder, yellow earth powder, elvan powder, or mixed powder of kaolin, yellow earth, and elvan was mixed with activated carbon, as a supplemental agent, and a binder to produce a carrier in a sphere, tube, hone somb, ring, cylinder, rod, fine spherical grain, plate, or seed shape. As another procedure, zeolite, silicon carbide, or carbon powder was mixed with activated carbon so as to have desirable porosity, mixed with a binder, and compacted into the above shapes to produce a carrier. The carrier as described above, or a carrier produced through a typical technology was immersed in an aqueous alumina solution, thereby creating the carrier having alumina sorbed in a thickness of 0.2 - 3 mm onto an internal side and a surface thereof.

[39] A size of polymer or activated carbon as the supplemental agent was 1 mesh or less and at a nanometer level in accordance with the size of the carrier. Kaolin powder, yellow earth powder, and elvan powder were mixed with each other in a weight ratio of 3:2:1.

[40] Additionally, the carrier was indirectly sintered using an oxidizing flame of 1000 - 1600 °C for 1 - 4 hours.

[41] EXAMPLE 2

[42] 139.5804 g of titanium sulfate (Ti (SO ) ) and 180.2256 g of tin chloride (SnCl , 2 4 2 4 SnCl ? 5H O) were dissolved in 2400 ml of anion-free water. Additionally, 25 % 4 2 ammonia water was dissolved in 1800 ml of anion-free water to produce a solution. [43] EXAMPLE 3

[44] Citric acid was mixed with 1200 ml of ion-free water in a ratio of 4/1 - 4/3, and the mixture was then blended with the two solutions of example 2 to produce a solution having a pH of 7 - 8. [45] EXAMPLE 4

[46] Any one of the carriers of example 1 was put in an airtight container in an amount of 1.5 kg. The container was vacuumized to remove impurities and air from pores of the carrier. Subsequently, the solution of example 3 was injected into the container in a vacuum, and the solution of example 2 was then injected. The solutions were agitated to be uniform, the container was slowly unvacuumized, and precipitation was conducted at atmospheric pressure for 1 - 2 hours.

[47] EXAMPLE 5

[48] The precipitate of example 4 was washed using anion-free water until Cl and SO 4 2- were not detected in the precipitate, dried at 90 - 150 °C for 10 - 20 hours, and indirectly sintered using a reducing flame of 400 - 700 °C for 2 - 5 hours.

[49] EXAMPLE 6

[50] 200 ml of catalyst having a diameter of 10 mm and a height of 15 mm, which was produced through examples 1 to 5, was put in a third of three reactors. 525 ppm SO , 2 520 ppm NO , 2085 ppm CO, and a material containing some oxygen and Ar were injected into a first reactor. Subsequently, a reaction occuned at 250 - 500 °C . [51] The above pollutants and CH were injected into the first reactor. Oxygen was fed 4 into a second reactor, and the pollutants were fed into the other second reactor in which the catalyst was packed. [52] At this stage, SO and NO were converted at conversion efficiencies of 96 % or ^{2 x} -1 more and 100 %, respectively, under conditions of an air speed of 2400 hr and a temperature of 350 - 400 °C , and selectivities of S and N were both 100 %. Even 2 though the reaction continued for a reaction time of 50 hours, catalytic activity was not reduced.

[53] EXAMPLE 7

[54] Titanium sulfate of titanium dioxide and tin chloride of tin dioxide were separately dissolved in cationic water in a weight ratio of 2 - 8 : 2 - 8, and the two solutions were mixed with each other. Ammonia was mixed with cationic water, and ammonia water was mixed with the two solutions.

[55] After a predetermined time, precipitate was extracted from the mixed solution, and then washed using cationic water through the same procedure as the above examples until chlorine ions and sulfate ions were not detected. Subsequently, the washed precipitate was dried at 90 - 120 °C for 1 - 10 hours, and sintered at 400 - 700 °C for 2 - 5 hours to produce the resulting precipitate. The resulting precipitate had a specific 2 -1 surface area of 95 - 120 m g and a rutile structure. [56] The resulting precipitate, that is, rutile, was mixed with highly pure alumina powder at a ratio of 6 - 9 (rutile) : 1 - 4 (alumina), compacted in various shapes, and sintered at 350 - 700 °C for 2 - 5 hours to produce the catalyst as a product.

[57] EXAMPLE 8

[58] 20 - 80 wt% titanium sulfate and 20 - 80 wt% tin chloride were mixed with each other to produce a mixed aqueous solution, or alternatively, they were separately dissolved in cationic water to produce different aqueous solutions and the aqueous solutions were then mixed with each other at the above ratio to produce the mixed aqueous solution.

[59] Highly pure alumina powder was mixed with the mixed aqueous solution in an amount of 10 - 50 % based on a weight of titanium dioxide and tin dioxide contained in the mixed aqueous solution, and then mixed with a predetermined amount of ammonia water. The resulting mixture was compacted in various shapes, washed with cationic water until sulfate ions and chlorine ions were not detected, dried at 90 - 150 °C for 1 - 10 hours, and sintered at 300 - 700 °C for 2 - 5 hours to produce a catalyst as a product. Industrial Applicability

[60] As described above, a method of producing a catalyst and the catalyst produced using the method according to the present invention are advantageous in that carbon monoxide, sulfur oxide, and nitrogen oxide are simultaneously removed using the catalyst, and costs of installation and maintenance are significantly reduced.

Claims

[1] A catalyst for simultaneously reducing sulfur oxide and nitrogen oxide into S and N , respectively, using carbon monoxide as a converting agent, comprising: 2 a carrier which includes aluminum oxide (alumina) and has various shapes, or which includes typical materials, has various shapes and is coated with the aluminum oxide; and a mixed metal in which titanium dioxide and tin dioxide are mixed with each other at a weight ratio of 2 - 8 : 2 - 8 and which is sorbed onto an internal side and a surface of the carrier so as to form a tetragonal system rutile (TiO ) 2 structure.

[2] A method of simultaneously reducing sulfur oxide and nitrogen oxide into S and N , respectively, using carbon monoxide as a converting agent, comprising: 2 installing a plurality of containers for receiving pollutants, which includes the carbon monoxide, the sulfur oxide, and the nitrogen oxide; feeding the pollutants, containing oxygen, into a first container; feeding methane (CH ) into the first container to separate the oxygen from the 4 pollutants; and feeding the remaining pollutants into a second container, in which a catalyst is packed, to react the pollutants in a presence of the catalyst as a product of claim 1.

[3] A catalyst for simultaneously reducing sulfur oxide and nitrogen oxide into S and N , respectively, using carbon monoxide as a converting agent, which is 2 produced through a method comprising: mixing and kneading aluminum oxide (alumina) powder, a solution, in which titanium sulfate (Ti (SO ) ) and tin chloride (SnCl , SnCl ? 5H O) of titanium 2 4 3 4 4 2 dioxide and tin dioxide are dissolved in cationic water in a weight ratio of 20 - 80 % (titanium sulfate) : 20 - 80 % (tin chloride), cationic water, and a predetermined amount of ammonia water; compacting the mixture in a predetermined shape; drying the compacted mixture; sintering the dried mixture; and washing the sintered mixture.

[4] A method of producing a catalyst for simultaneously reducing sulfur oxide and nitrogen oxide into S and N , respectively, using carbon monoxide as a 2 converting agent, comprising: mixing and kneading aluminum oxide (alumina) powder, a solution, in which titanium sulfate (Ti (SO ) ) and tin chloride (SnCl , SnCl ? 5H O) of titanium 2 4 3 4 4 2 dioxide and tin dioxide are dissolved in cationic water at a weight ratio of 20 - 80 % (titanium sulfate) : 20 - 80 % (tin chloride), cationic water, and a predetermined amount of ammonia water; compacting the mixture in a predetermined shape; drying the compacted mixture; sintering the dried mixture; and washing the sintered mixture.

[5] The catalyst as set forth in claim 1 or 3, wherein the aluminum oxide is applied on the internal side and the surface of the carrier, which is produced through a typical technology and includes mullite, codierite, a mixture of magnesium oxide and the aluminum oxide, or a mixture of the aluminum oxide and zirconia, in a thickness of 0.2 - 3 mm,

[6] The method as set forth in claim 2 or 4, wherein aluminum oxide is applied on an internal side and a surface of a carrier, which is produced through a typical technology and includes mullite, codierite, a mixture of magnesium oxide and the aluminum oxide, or a mixture of the aluminum oxide and zirconia, in a thickness of 0.2 - 3 mm.