Title of Invention	CATALYST SYSTEM AND METHOD FOR THE REDUCTION OF NOX
Abstract	A catalyst system for the reduction of NOx comprises a catalyst comprising a metal oxide catalyst support, a catalytic metal oxide comprising at least one of gallium oxide or silver oxide, and at least one promoting metal selected from the group consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof. The catalyst system further comprises a gas stream comprising an organic reductant comprising oxygen. A method for reducing NOx utilizing the said catalyst system is also provided.

Title of Invention

CATALYST SYSTEM AND METHOD FOR THE REDUCTION OF NOX

Abstract

A catalyst system for the reduction of NOx comprises a catalyst comprising a metal oxide catalyst support, a catalytic metal oxide comprising at least one of gallium oxide or silver oxide, and at least one promoting metal selected from the group consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof. The catalyst system further comprises a gas stream comprising an organic reductant comprising oxygen. A method for reducing NOx utilizing the said catalyst system is also provided.

Full Text	146984 CATALYST SYSTEM AND METHOD FOR THE REDUCTION OF NOX BACKGROUND OF THE INVENTION This invention relates generally to a catalyst system and method for the reduction of nitrogen oxide emissions and more particularly to a catalyst system that comprises a multi-component catalyst and a reductant. Methods have long been sought to reduce the deleterious effects of air pollution caused by byproducts resulting from the imperfect high-temperature combustion of organic materials. When combustion occurs in the presence of excess air and at high temperatures, harmful byproducts, such as nitrogen oxides, commonly known as NOX, are created. NOX and subsequent derivatives have been suggested to play a major role in the formation of ground-level ozone that is associated with asthma and other respiratory ailments. NOX also contributes to soot formation, which is linked to a number of serious health effects, as well as to acid rain and the deterioration of coastal estuaries. As a result, NOX emissions are subject to many regulatory provisions limiting the amount of NOX that may be present in effluent gas vented into the surrounding environment. One known method for dealing with NOX involves the use of selective catalytic reduction (SCR) to reduce NOX to nitrogen gas (N2) using ammonia (NH3) as a reductant. However, as ammonia's own hazardous consequences are well known, the use of NH3 in an SCR system presents additional environmental and other problems that must also be addressed. As regulatory agencies continue to drive limits on NOX emission lower, other regulations are also driving down the permissible levels of NH3 that may be emitted into the atmosphere. Because of regulatory limits on ammonia slip, the use of hydrocarbons and their oxygen derivatives for NOX reduction in an SCR process is very attractive. Numerous catalysts have been suggested for this purpose including zeolites, perovskites, and metals on metal oxide catalyst support. However, existing catalyst systems have either low activity or narrow region of working temperatures or low stability to water, which are detrimental to practical use. U.S. Patent 6,703,343 teaches catalyst systems for use in NOX reduction. However, 1 146984 these catalyst systems require a specially synthesized metal oxide catalyst support with very low level of impurities. Therefore there is a need for an effective catalyst system to reduce NOX emissions, which system is stable and operable at a wide range of temperatures. BRIEF DESCRIPTION OF THE INVENTION The present inventors have identified catalyst systems that are surprisingly effective using commercially available metal oxide catalyst supports with common impurities present. Thus, in one embodiment the present invention is a catalyst system for the reduction of NOX, which catalyst system comprises a catalyst comprising a metal oxide catalyst support, a catalytic metal oxide comprising at least one of gallium oxide or silver oxide, and at least one promoting metal selected from the group consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof. The catalyst system further comprises a gas stream comprising an organic reductant comprising oxygen. Another embodiment of the present invention is a catalyst system for the reduction of NOX, which catalyst system comprises a catalyst comprising (i) a metal oxide catalyst support comprising alumina, (ii) at least one of gallium oxide or silver oxide present in an amount in the range of from about 5 mole % to about 31 mole %; and (iii) a promoting metal or a combination of promoting metals present in an amount in the range of from about 1 mole % to about 22 mole % and selected from the group consisting of silver; cobalt; molybdenum; tungsten; indium and molybdenum; indium and cobalt; and indium and tungsten. The catalyst system further comprises a gas stream comprising (A) water in a range of from about 1 mole % to about 12 mole %; (B) oxygen in a range of from about 1 mole % to about 15 mole %; and (C) an organic reductant comprising oxygen and selected from the group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl carbonate and combinations thereof. The organic reductant and the NOX are present in a carbon:NOx molar ratio from about 0.5:1 to about 24:1. 2 146984 In yet another embodiment the present invention is a method for reducing NOX, which comprises the steps of: providing a gas mixture comprising NOX and an organic reductant comprising oxygen; and contacting the gas mixture with a catalyst. The catalyst comprises a metal oxide catalyst support, a catalytic metal oxide comprising at least one of gallium oxide or silver oxide and at least one promoting metal selected from the group consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof. In yet another embodiment the present invention is a method for reducing NOX, which comprises the steps of: providing a gas stream comprising (A) NOX; (B) water from about 1 mole % to about 12 mole %; (C) oxygen from about 1 mole % to about 15 mole %; and (D) an organic reductant comprising oxygen selected from the group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl carbonate and combinations thereof; and contacting said gas stream with a catalyst comprising (i) a metal oxide catalyst support comprising at least one member selected from the group consisting of alumina, titania, zirconia, silicon carbide, and ceria; (ii) at least one of gallium oxide or silver oxide in the range of from about 5 mole % to about 31 mole %; and (iii) a promoting metal or a combination of promoting metals in the range of from about 1 mole % to about 22 mole % and selected from the group consisting of silver; cobalt; molybdenum; tungsten; indium and molybdenum; indium and cobalt; and indium and tungsten; wherein said organic reductant and said NOX are present in a carbon:NOx molar ratio from about 0.5:1 to about 24:1; and wherein said contact is performed at a temperature in a range of from about 1000C to about 600°C and at a space velocity in a range of from about 5000 hr-1 to about 100000 hr1. Various other features, aspects, and advantages of the present invention will become more apparent with reference to the following description and appended claims. DETAILED DESCRIPTION OF THE INVENTION In the following specification and the claims, which follow, reference will be made to a number of terms which shall be defined to have the following meanings. The 3 146984 singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. In one embodiment the present invention comprises a catalyst system for the selective reduction of NOX, which catalyst system comprises a catalyst and a reductant. The catalyst comprises a metal oxide catalyst support, a catalytic metal oxide, and a promoting metal. The reductant comprises an organic compound comprising oxygen. The metal oxide catalyst support may comprise alumina, titania, zirconia, ceria, silicon carbide or any mixture of these materials. Typically, the metal oxide catalyst support comprises gamma-alumina with high surface area comprising impurities of at least about 0.2% by weight in one embodiment and at least about 0.3% by weight impurities in another embodiment. The metal oxide catalyst support may be made by any method known to those of skill in the art, such as co-precipitation, spray drying and sol-gel methods for example. The catalyst also comprises a catalytic metal oxide. In one embodiment the catalytic metal oxide comprises at least one of gallium oxide or silver oxide. In a particular embodiment the catalyst comprises from about 5 mole % to about 31 mole % of gallium oxide. In another particular embodiment the catalyst comprises from about 12 mole % to about 31 mole % of gallium oxide. In still another particular embodiment the catalyst comprises from about 18 mole % to about 3.1 mole % of gallium oxide, wherein in all cases mole percent is determined by dividing the number of moles of catalytic metal by the total number of moles of the metal components in the catalyst, including the catalyst support and any promoting metal present. In another particular embodiment the catalyst comprises from about 0.5 mole % to about 31 mole % of silver oxide. In another particular embodiment the catalyst comprises from about 10 mole % to about 25 mole % of silver oxide. In still another particular embodiment the catalyst comprises from about 12 mole % to about 20 mole % of silver oxide, wherein in all cases mole percent is determined by dividing the number of moles of catalytic metal by the total number of moles of the metal components in the catalyst, including the metal components of the catalyst support and any promoting metal present. 4 146984 The catalyst also comprises at least one promoting metal. The promoting metal may comprise at least one of silver, cobalt, molybdenum, tungsten or indium. Additionally, the promoting metal may also be a combination of more than one of these metals. The catalyst typically comprises from about 1 mole % to about 22 mole % of the promoting metal. In some embodiments the catalyst comprises from about 1 mole % to about 12 mole % of the promoting metal and in some other embodiments from about 1 mole % to about 7 mole % of the promoting metal. In one particular embodiment the catalyst comprises from about 1 mole % to about 5 mole % of the promoting metal. It should be appreciated that the term "promoting metal" is meant to encompass elemental metals, metal oxides or salts of the promoting metal, such as CO2O3 for example. In one particular embodiment wherein the catalytic metal oxide comprises silver oxide, the catalyst system must further comprise at least one promoting metal which is selected from the group consisting of cobalt, molybdenum, tungsten, indium, and mixtures thereof. The catalysts may be produced by an incipient wetness technique, comprising the application of homogenous and premixed precursor solutions for catalytic metal oxide and promoting metal contacted with the metal oxide catalyst support. The metal oxide particles for the catalyst support are typically calcined before application of precursor solution. In some embodiments a primary drying step at about 80°C to about 120°C for about 1 -2 hours is followed by the main calcination process. The calcination may be carried out at a temperature in the range of from about SOOT to about 800°C. In some embodiments the calcination is carried out at a temperature in a range of from about 650°C to about 725°C. In some embodiments the calcination is done for about 2 hours to about 10 hours. In some other embodiments the calcination is done for about 4 hours to about 8 hours. The particles are sifted to collect and use those which are from about 0.1 to about 1000 micrometers in diameter. In one embodiment the particle size ranges from about 2 micrometers to about 50 micrometers in diameter. Based on the surface area and total pore volume of the metal oxide catalyst support particles, the desired loading of the catalyst may then be calculated. As will be appreciated by those of ordinary skill in the art, the surface area and porosity may be up to about 20-30% lower in the final catalyst product, as a 5 146984 result of catalyst loading. The loading of the catalyst is determined by the total pore volume of the support, which is the volume of metal precursors that can be loaded by incipient wetness. The precursor loading is chosen such that the amount of metal is typically less than a monolayer of the active metal oxide on the metal oxide catalyst support. In some embodiments twice the pore volume is used as the total volume of precursor to load and the metal loading is taken in the range of from about 1 millimole to about 5 millimoles of the mixture of catalytic metal oxide and promoting metal per gram of metal oxide catalyst support. In the subsequent steps of preparing the catalyst, precursor solutions of the catalytic metal oxide and, one or more promoting metals may be prepared. Precursor solutions may be prepared in aqueous media, in hydrophilic organic media, or in a mixture thereof. Hydrophilic organic media comprise carboxylic acids, alcohols and mixtures thereof such as, but not limited to, acetic acid or ethanol. The solutions are typically made by mixing solvent with metal salts, such as, but not limited to, metal nitrates, citrates, oxalates, acetylacetonates, molybdates, or benzoates, in an amount to create a solution of appropriate molarity based on the desired catalyst composition. In some embodiments the metal salt is a molybdenum heteropoly anion or ammonium molybdate. The methods used for preparing the catalyst system are known in the art and include depositing metal oxide catalyst support in a honey-comb support in a wash coating method or extruding in a slurry into a desired form. The purity of the metal precursors for both catalytic metal oxide and promoting metal is in the range of from about 95 % to about 99.999 % by weight. In one embodiment, all the metal precursors are mixed together and are as homogeneous as possible prior to addition to the metal oxide catalyst support. In some other embodiments different metal precursors are added sequentially to the metal oxide catalyst support. In one embodiment, the desired volume of the precursor solution is added to coat the metal oxide catalyst support and create a catalyst with the desired final catalyst loading. Once the metal salt solution or solutions have been added to the metal oxide catalyst support, the catalyst may optionally be left to stand for a period of time, in some embodiments about 6 to 10 hours. The catalyst is then dried for a period of time at a desired temperature. In a particular embodiment the catalyst may be dried under a 6 146984 vacuum, optionally while a nitrogen stream is passed over the mixture. Finally, the catalyst may be calcined at a desired temperature and for a desired time to create the final catalyst product. r Catalysts according to exemplary embodiments of the present invention may be created using either a manual or an automated process. Typically, a manual process is used for the preparation of catalysts of a larger mass, such as about 1 to about 20 grams (g) for example. An automated process is typically used when the catalysts are of a smaller mass, such as about 5 milligrams (mg) to about 100 mg, for example. Generally, manual and automated processes for preparation of the catalyst are similar with the exception that an automated process involves automated measuring and dispensing of the precursor solutions to the metal oxide catalyst support. The reductant for use in the catalyst system of exemplary embodiments of the present invention comprises an organic compound comprising oxygen. Said organic compounds comprising oxygen are fluid, either as a liquid or gas, such that they may flow through the catalyst when introduced into an effluent gas stream for use in a catalyst system for the reduction of NOX. Typically, hydrocarbons comprising oxygen of less than about 16 carbon atoms will be fluid, although hydrocarbons comprising oxygen with higher numbers of carbon atoms may also be fluid, for example, depending on the chemical structure and temperature of the gas stream. The organic compounds comprising oxygen suitable for use as reductants typically comprise a member selected from the group consisting of an alcohol, an ether, an ester, a carboxylic acid, an aldehyde, a ketone, a carbonate and combinations thereof. In some embodiments the organic compounds comprising oxygen suitable for use as reductants comprise at least one functional group selected from the group consisting of hydroxy, alkoxy, carbonyl, carbonate and combinations thereof. Some non-limiting examples of organic compounds comprising oxygen suitable for use as reductants comprise methanol, ethyl alcohol, 1-butanol, 2-butanol, 1-propanol, iso-propanol, dimethyl ether, dimethyl carbonate and combinations thereof. The catalyst system may be used in conjunction with any process or system in which it may be desirable to reduce NOX emissions, such as a gas turbine; a steam turbine; a 7 146984 boiler; a locomotive; or a transportation exhaust system, such as, but not limited to, a diesel exhaust system. The catalyst system may also be used in conjunction with systems involving generating gases from burning coal, burning volatile organic compounds (VOC), or in the burning of plastics; or in silica plants, or in nitric acid plants. The catalyst is typically placed at a location within an exhaust system where it will be exposed to effluent gas comprising NOX. The catalyst may be arranged as a packed or fluidized bed reactor, coated on a monolithic, foam, mesh or membrane structure, or arranged in any other manner within the exhaust system such that the catalyst is in contact with the effluent gas. As will be appreciated by those ordinarily skilled in the art, although catalytic reactions are generally complex and involve many steps, the overall basic selective catalytic reduction reaction process for the reduction of NOX is believed to occur as follows: NOX + O2 + organic reductant -> N2 + CO2 + H2O (1) The effluent gas stream usually comprises air, water, CO, CO2, NOX, and may also comprise other impurities. Additionally, uncombusted or incompletely combusted fuel may also be present in the effluent gas stream. The organic reductant is typically fed into the effluent gas stream to form a gas mixture, which is then fed through the catalyst. Sufficient oxygen to support the NOX reduction reaction may already be present in the effluent gas stream. If the oxygen present in the gas mixture is not sufficient for the NOX reduction reaction, additional oxygen gas may also be introduced into the effluent gas stream in the form of oxygen or air. In some embodiments the gas stream comprises from about 1 mole % to about 21 mole % of oxygen gas. In some other embodiments the gas stream comprises from about 1 mole % to about 15 mole % of oxygen gas. One advantage of embodiments of the present invention is that the reduction reaction may take place in "reductant lean" conditions. That is, the amount of reductant added to the effluent gas to reduce the NOX is generally low. Reducing the amount of reductant to convert the NOX to nitrogen may provide for a more efficient process that 8 146984 has decreased raw material costs. The molar ratio of reductant to NOX is typically in a range of from about 0.25:1 to about 6:1. In other embodiments the ratio is typically such that the ratio of carbon atoms in the reductant is about 0.5 to about 24 moles per mole of NOX. In some other embodiments the organic reductant and the NOX are present in a carbon:NOx molar ratio in a range of from about 0.5:1 to about 15:1. In a particular embodiment the organic reductant and the NOX are present in a carbon:NOx molar ratio in a range of from about 0.5:1 to about 8:1. The reduction reaction may take place over a range of temperatures. Typically, the temperature may range in one embodiment from about 100°C to about 600°C, in another embodiment from about 200°C to about 500°C and in still another embodiment from about 350°C to about 450°C. The reduction reaction may take place under conditions wherein the gas mixture is configured to have a space velocity in one embodiment in a range of from about 5000 reciprocal hours (hr-1) to about 100000 hr-1, in another embodiment in a range of from about 8000 hr-1 to about 50000 hr-1 and in still another embodiment in a range of from about 8000 hr-1 to about 40000 hr-1. Exemplary embodiments of the catalyst system may also advantageously be used in wet conditions. In particular embodiments NOX reduction accomplished using exemplary embodiments of the present invention may be effective in effluent gas streams comprising water. In some embodiments the gas stream comprises from about 1 mole % to about 12 mole % of water and in some other embodiments from about 2 mole % to about 10 mole % of water. Without further elaboration, it is believed that one skilled in the art can, using the description herein, utilize the present invention to its fullest extent. The following examples are included to provide additional guidance to those skilled in the art in practicing the claimed invention. The examples provided are merely representative of the work that contributes to the teaching of the present application. Accordingly, these examples are not intended to limit the invention, as defined in the appended claims, in any manner. 9 146984 EXAMPLES Catalysts were prepared and used in combination with reductants in accordance with exemplary embodiments of the present invention. The conversion of the NOX was analyzed over a variety of experimental conditions, including varying catalyst compositions, reductants, reaction temperatures, and reductant to NOx ratios. In the following examples catalyst samples were prepared each having a gamma- alumina catalyst support commercially available from Saint-Gobain NorPro of Stow, Ohio. The alumina catalyst support had a purity of 99.5% to 99.7%. The alumina support was first calcined at 725°C for 6 hours in presence of an oxidant. The oxidant may be air or an oxidant gas comprising about 1 % to about 21% of oxygen in nitrogen. The alumina particles were then sifted to collect catalyst support having a particle size diameter of from about 450 micrometers to about 1000 micrometers. Prior to loading, the catalyst support had a surface area of about 240 square meters per gram (m2/g) and a pore volume of 0.796 milliliters per gram (mL/g). Gallium was used as the metal for the catalytic metal oxide added to the alumina. The gallium was added in a soluble form to wet the alumina support and was made from a solution of gallium nitrate having the formula Ga(NO3)3 • 6H2O. The solution was made by combining deionized water with gallium nitrate having a purity of 99.999% (metals basis) obtained from Alfa-Aesar of Ward Hill, Massachusetts. Millipore water having a resistivity of 18 megaohm-centimeters was employed in all operations. For the promoting metal an aqueous solution of the nitrate salt of the desired metal(s) also having a purity of 99.999% (metals basis) and obtained from Alfa-Aesar was added to the alumina support. All the metal precursors were mixed together and were as homogeneous as possible prior to addition to the alumina support. The catalysts were left to stand for 6 to 10 hours and were then dried under a dynamic vacuum with a nitrogen influx for 4 to 5 hours at 80°C. Finally, the dried catalyst was heat treated. The heat profile for this treatment began with an increase from 25°C to 110°C at 1.4°C per minute. The catalyst was held at 110°C for 1.5 hours, after which the temperature was ramped at 5°C per minute to a value of 650°C. The catalyst was held 10 146984 6 hours at this temperature and then allowed to cool over a period of about 4 to 6 hours. Catalysts were tested in a 32-tube high-throughput heterogeneous catalyst-screening micro-reactor. The reactor was a heated, common headspace gas distribution manifold that distributed a reactant stream equally via matched capillaries to parallel reactor tubes. The manifold had heated capabilities, allowing pre-heating of the reactant stream and vaporization of liquid reactants prior to distribution. The entire heated manifold assembly was mounted on a vertical translation stage, raised and lowered via pneumatic pressure. Reactor tubes were inserted in a gold-coated 10 centimeter (cm) thick insulated copper reactor block (dimension 13.5 cm x 25 cm),, which was electrically heated to vary temperature between 200°C to 650°C. Chemically inert KALREZ™ o-rings available from DuPont of Wilmington, Delaware, served as viscoelastic end-seals on either end of each reactor tube. Reactor tubes were made of INCONEL 600 ™ tubing with 0.635 cm outside diameter and 0.457 cm internal diameter, available from Inco Alloys/Special Metals of Saddle Brook, New Jersey. The tubes were free to slide vertically through the gold-coated copper heating block. Each tube contained a quartz wool frit, on which the catalyst samples of about 0.050 g were placed in the center of each of the tubes through which a reactant stream of a blended gas mixture comprising NOX and reductant simulating an effluent gas stream was passed. A single bypass tube was used to ensure equal flow through each of the 32 testing tubes. The fittings were connected to a distribution manifold for delivery of the blended gas mixture. The components of the blended gas mixture were fed to a common mixing manifold using electronic mass flow controllers, and then routed to the distribution manifold. The pressure in the distribution manifold was maintained at about 275.8 kilopascals (kPa). Reactor temperature and flow control were fully automated. Once loaded in the tubes, the catalysts were heat-treated under airflow as described herein above and then reacted with the blended gas mixture. The reactor effluent was sent to heated sampling valves that selected tubes in series and fed the continuous 11 146984 stream to a chemiluminescent analyzer. Any stream that was not routed to the analytical device was routed to a common vent. Switching valves for routing gases were computer controlled and actuated in a pre- determined time-based sequence. The chemiluminescent analyzer was connected to a computer-based data-logging system. Data corresponding to reactor tube effluent composition were time-stamped and stored. Data from the bypass tube were also stored as a reference to the inlet composition of the catalyst reactor tubes. This permitted the combination of data to determine activity and selectivity of each catalyst sample. For NOX reduction testing the reactant stream of the blended gas mixture comprised reductant, about 200 ppm NOX, 12% by volume oxygen, 7% by volume water and the balance nitrogen. The type and amount of reductant in the stream varied depending on the experiments being conducted. The flow rate of the blended gas mixture through each of the tubes was 33 standard cubic centimeters per minute (sccm) per tube. Table 1 shows the compositions of the catalyst samples prepared, with compositions expressed in mole percent of each promoting metal and/or catalytic metal present in the catalyst. The balance of the composition was alumina from the alumina catalyst support. Mole percent was determined for each component by dividing the number of moles of that component by the total number of moles of the metal components in the catalyst, including the metal components of the metal oxide catalyst support. The abbreviation "C.Ex." means Comparative Example. Comparative example 1 consists only of the alumina support. 12 146984 TABLE 1 Example Ga In Ag Co Mo w C.Ex. 1 0 0 0 0 0 0 C.Ex. 2 29 0 0 0 0 0 C.Ex. 3 0 2 0 0 0 0 CEx. 4 0 4 0 0 0 0 C.Ex. 5 0 0 2 0 0 0 C.Ex. 6 0 0 5 0 0 0 C.Ex. 7 27 2 0 0 0 0 Ex.1 27 0 2 0 0 0 Ex.2 25 0 4 0 0 0 Ex.3 27 0 0 2 0 0 Ex.4 25 0 0 4 0 0 Ex.5 25 2 0 2 0 0 Ex.6 22 3 0 3 0 0 Ex.7 27 0 0 0 2 0 Ex.8 25 0 0 0 5 0 Ex.9 22 0 0 0 8 0 Ex.10 22 3 0 0 3 0 Ex.11 21 6 0 0 1 . 0 Ex.12 27 0 0 0 0 2 Ex.13 25 0 0 0 0 4 Ex.14 20 0 0 0 0 8 Ex.15 22 6 0 0 0 1 Ex.16 21 3 0 0 0 3 A first set of experiments was conducted in which various catalyst samples were prepared and tested with various reductants using the described testing procedure at 350°C. The results in Table 2 show the percentage of NOX converted for each of the catalyst systems. The example and comparative example numbers in Table 2 correspond to the catalyst compositions in the examples and comparative examples of Table 1. Although the molar ratio of reductant to NOX varied with the reductant used, the molar ratio of carbon:NOx was generally equal to about 2:1 for each of the experimental systems. The abbreviation "NBA" means 1-butanol. 13 146984 TABLE 2 Reductants Example MeOH EtOH i-PrOH NBA C.Ex. 1 12 35 30 35 C.Ex. 2 18 32 33 31 C.Ex. 3 29 35 28 33 C.Ex. 4 26 34 43 32 C.Ex. 5 6 24 66 42 C.Ex. 6 7 14 36 21 Ex.1 12 59 97 55 Ex.2 2 14 30 19 Ex.3 15 34 31 30 Ex.4 43 56 25 46 Ex.5 42 46 28 41 Ex.6 34 39 33 39 As shown in Table 2, Example 1 having a combination of gallium oxide as a catalytic metal oxide and silver as a promoting metal showed particularly good results using reductants such as ethanol, iso-propanol and 1-butanol. Example 4 comprising gallium and cobalt showed good performance with methanol, ethanol and NBA. Examples 5 and 6 comprising cobalt, indium and gallium also showed good performance with methanol, ethanol, and 1 -butanol. A second set of experiments was conducted in which various catalyst samples were prepared and tested with various reductants using the described testing procedure at 400°C. The results in Table 3 show the percentage of NOX converted for each of the catalyst systems. The example and comparative example numbers in Table 3 correspond to the catalyst compositions identified in the examples and comparative examples of Table 1. Although the molar ratio of reductant to NOX varied with the reductant used, the molar ratio of carbon:NOx was generally equal to about 6:1 for each of the experimental systems. The abbreviations "DMC", IPA", and "NBA" mean dimethyl carbonate, iso-propyl alcohol, and 1-butanol, respectively. 14 146984 TABLE 3 Catalyst Composition Reductant Example Ga In Ag Co Mo w MeOH DMC EtOH IPA NBA C.Ex. 2 29 0 0 0 0 0 20 38 57 55 57 C.Ex. 3 0 2 0 0 0 0 18 34 55 61 56 C.Ex. 5 0 0 2 0 0 0 21 30 95 96 83 C.Ex. 7 27 2 0 0 0 0 28 48 62 54 57 Ex.3 27 0 0 2 0 0 17 79 49 42 37 Ex.6 22 3 0 3 0 0 18 49 40 40 33 Ex.7 27 0 0 0 2 0 28 44 60 52 56 Ex.8 25 0 0 0 5 0 34 54 76 70 65 Ex.9 22 0 0 0 8 0 50 77 44 31 41 Ex.10 22 3 0 0 3 0 35 62 47 33 42 Ex.11 21 6 0 0 1 0 25 25 65 28 21 Ex.12 27 0 0 0 0 2 37 55 19 22 68 Ex.13 25 0 0 0 0 4 53 32 28 24 21 Ex.14 20 0 0 0 0 8 65 36 30 31 29 Ex.15 22 6 0 0 0 1 24 58 50 13 55 Ex.16 21 3 0 0 0 3 41 64 60 22 61 While all of the catalyst samples showed good or better performance compared with comparative examples, example 8 having 5 mole % molybdenum and 25 mole % gallium showed good results with all of the five oxygenated reductants. In general the catalyst systems in accordance with exemplary embodiments of the present method were successful in reducing some NOX in each case. A third set of experiment was conducted in which methanol was tested as a reductant at 400°C in presence of a gas mixture comprising 200 ppm NOX, 4% water, and 13% O2 and the balance nitrogen at a nominal space velocity of 28,000 hr1. The catalyst compositions along with the catalyst activity for each experiment are given in Table 4. The balance of moles catalyst comprises the metal oxide catalyst support. Although the molar ratio of reductant to NOX varied with the reductant used, the molar ratio of carbon:NC\ was generally equal to about 6:1 for each of the experimental systems. The catalyst activity is expressed in moles of NOX converted to N2 per gram of catalyst per hour. 15 146984 TABLE 4 Example Catalyst Reductant Ga Ag In MeOH Ex.17 6 6 19 5.2E-06 Ex.18 6 13 13 1.0E-05 Ex.19 6 19 6 1.6E-05 Ex.20 13 6 13 5.2E-06 Ex.21 0 19 13 2.0E-05 Ex.22 0 13 19 5.9E-07 Ex.23 29 2 0 8.4E-08 Ex.24 0 16 16 1.7E-05 Ex.25 9 11 11 1.1E-05 Ex.26 5 16 10 1.6E-5 C.Ex. 8 31 0 0 6.3E-07 Various embodiments of this invention have been described in fulfillment of the various needs that the invention meets. It should be recognized that these embodiments are merely illustrative of the principles of various embodiments of the present invention. Numerous modifications and adaptations thereof will be apparent to those skilled in the art without departing from the spirit and scope of the present invention. Thus, it is intended that the present invention cover all suitable modifications and variations as come within the scope of the appended claims and their equivalents. 16 146984 What is claimed is: 1. A catalyst system for the reduction of NOX comprising: a catalyst comprising a metal oxide catalyst support, a catalytic metal oxide comprising at least one of gallium oxide or silver oxide, and at least one promoting metal selected from the group consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof; and a gas stream comprising an organic reductant comprising oxygen. 2. The catalyst system of claim 1, wherein said metal oxide catalyst support comprises at least one member selected from the group consisting of alumina, titania, zirconia, ceria, silicon carbide and mixtures thereof. 3. The catalyst system of claim 1, wherein said catalytic metal oxide comprises gallium oxide in a range of from about 5 mole % to about 31 mole %. 4. The catalyst system of claim 1, wherein said catalytic metal oxide comprises gallium oxide in a range of from about 18 mole % to about 31 mole %. 5. The catalyst system of claim 1, wherein said catalytic metal oxide comprises silver oxide in the range of from about 0.5 mole % to about 31 mole %. 6. The catalyst system of claim 1, wherein said catalyst comprises said promoting metal in a range of from about 1 mole % to about 22 mole %. 7. The catalyst system of claim 1, wherein said catalyst comprises said promoting metal in a range of from about 1 mole % to about 7 mole %. 8. The catalyst system of claim 1, wherein the catalytic metal oxide comprises gallium oxide and the promoting metal comprises silver or the combination of indium and silver. 9. The catalyst system of claim 1, wherein the catalytic metal oxide comprises silver oxide and the promoting metal comprises of indium. 17 146984 10. The catalyst system of claim 1, wherein said organic reductant is selected from the group consisting of an alcohol, an ether, an ester, a carboxylic acid, an aldehyde, a ketone, a carbonate and combinations thereof. 11. The catalyst system of claim 1, wherein said organic reductant is selected from the group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl carbonate and combinations thereof. 12. The catalyst system of claim 1, wherein said organic reductant and said NOX are present in a carbon:NOx molar ratio from about 0.5:1 to about 24:1. 13. The catalyst system of claim 1, wherein said organic reductant and said NOX are present in a carbon:NOx molar ratio from about 0.5:1 to about 8:1 14. The catalyst system of claim 1, wherein said gas stream further comprises water in a range of from about 1 mole % to about 12 mole %. 15. The catalyst system of claim 1, wherein said gas stream further comprises oxygen gas in a range of from about 1 mole % to about 21 mole %. 16. The catalyst system of claim 1, wherein NOX is present in effluent gas from a combustion source, said combustion source comprising at least one of a gas turbine, a boiler, a locomotive, a transportation exhaust system, coal burning, plastics burning, volatile organic compound burning, a silica plant, or a nitric acid plant. 17. A catalyst system for the reduction of NOX comprising: a catalyst comprising (i) a metal oxide catalyst support comprising alumina, (ii) at least one of gallium oxide or silver oxide present in an amount in the range of from about 5 mole % to about 31 mole %; and (iii) a promoting metal or a combination of promoting metals present in an amount in the range of from about 1 mole % to about 22 mole % and selected from the group consisting of silver; cobalt; molybdenum; tungsten; indium and molybdenum; indium and cobalt; and indium and tungsten; and a gas stream comprising (A) water in a range of from about 1 mole % to about 12 mole'%; (B) oxygen in a range of from about 1 mole % to about 15 mole %; and (C) 18 146984 an organic reductant comprising oxygen and selected from the group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl carbonate and combinations thereof; wherein said organic reductant and said NOX are present in a carbon:NOx molar ratio from about 0.5:1 to about 24:1. 18. A method for reducing NOX, which comprises the steps of: providing a gas mixture comprising NOX and an organic reductant comprising oxygen; and contacting said gas mixture with a catalyst, wherein said catalyst comprises a metal oxide catalyst support, a catalytic metal oxide comprising at least one of gallium oxide or silver oxide, and at least one promoting metal selected from the group consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof. 19. The method of claim 18, wherein said contact is at a temperature in a range of from about 100 °C to about 600°C. 20. The method of claim 18, wherein said contact is at a temperature in a range of from about 200°C to about 500°C. 21. The method of claim 18, wherein said contact is performed at a space velocity in a range of from about 5000 hr"1 to about 100000 hr"1. 22. The method of claim 18, wherein said metal oxide catalyst support comprises at least one of alumina, titania, zirconia, silicon carbide or ceria. 23. The method of claim 18, wherein said catalytic metal oxide comprises gallium oxide in the range of from about 5 mole % to about 31 mole %. 24. The method of claim 18, wherein said catalyst comprises said promoting metal from about 1 mole % to about 22 mole %. 19 146984 25. The method of claim 18, wherein said organic reductant is selected from the group consisting of an alcohol, an ether, an ester, a carboxylic acid, an aldehyde, a ketone, a carbonate and combinations thereof. 26. The method of claim 18, wherein said organic reductant is selected from the group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl carbonate and combinations thereof. 27. The method of claim 18, wherein said organic reductant and said NOX are present in a carbon:NOx molar ratio from about 0.5:1 to about 24:1. 28. The method of claim 18, wherein said gas stream comprises water from about 1 mole % to about 12 mole %. 29. The method of claim 18, wherein said gas stream comprises oxygen from about 1 mole % to about 21 mole %. 30. The method of claim 18, wherein NOX is present said effluent gas from a combustion source, said combustion source comprising at least one of a gas turbine, a boiler, a locomotive, a transportation exhaust system, coal burning, plastics burning, volatile organic compound burning, a silica plant, or a nitric acid plant. 31. A method for reducing NOX, which comprises the steps of: providing a gas stream comprising (A) NOx; (B) water from about 1 mole % to about 12 mole %; (C) oxygen from about 1 mole % to about 15 mole %; and (D) an organic reductant comprising oxygen selected from the group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl carbonate and combinations thereof; and contacting said gas stream with a catalyst comprising (i) a metal oxide catalyst support comprising at least one member selected from the group consisting of alumina, titania, zirconia, silicon carbide, and ceria; (ii) at least one of gallium oxide or silver oxide in the range of from about 5 mole % to about 31 mole %; and (iii) a promoting metal or a combination of promoting metals in the range of from about 1 20 146984 mole % to about 22 mole % and selected from the group consisting of silver; cobalt; molybdenum; tungsten; indium and molybdenum; indium and cobalt; and indium and tungsten; 21 wherein said organic reductant and said NOX are present in a carbon:NOX molar ratio from about 0.5:1 to about 24:1; and wherein said contact is performed at a temperature in a range of from about 100°C to about 600°C and at a space velocity in a range of from about 5000 hr-1 to about 100000 hr-1. A catalyst system for the reduction of NOx comprises a catalyst comprising a metal oxide catalyst support, a catalytic metal oxide comprising at least one of gallium oxide or silver oxide, and at least one promoting metal selected from the group consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof. The catalyst system further comprises a gas stream comprising an organic reductant comprising oxygen. A method for reducing NOx utilizing the said catalyst system is also provided.

Full Text

146984
CATALYST SYSTEM AND METHOD FOR THE REDUCTION OF NOX
BACKGROUND OF THE INVENTION
This invention relates generally to a catalyst system and method for the reduction of
nitrogen oxide emissions and more particularly to a catalyst system that comprises a
multi-component catalyst and a reductant.
Methods have long been sought to reduce the deleterious effects of air pollution
caused by byproducts resulting from the imperfect high-temperature combustion of
organic materials. When combustion occurs in the presence of excess air and at high
temperatures, harmful byproducts, such as nitrogen oxides, commonly known as NOX,
are created. NOX and subsequent derivatives have been suggested to play a major
role in the formation of ground-level ozone that is associated with asthma and other
respiratory ailments. NOX also contributes to soot formation, which is linked to a
number of serious health effects, as well as to acid rain and the deterioration of coastal
estuaries. As a result, NOX emissions are subject to many regulatory provisions
limiting the amount of NOX that may be present in effluent gas vented into the
surrounding environment.
One known method for dealing with NOX involves the use of selective catalytic
reduction (SCR) to reduce NOX to nitrogen gas (N2) using ammonia (NH3) as a
reductant. However, as ammonia's own hazardous consequences are well known, the
use of NH3 in an SCR system presents additional environmental and other problems
that must also be addressed. As regulatory agencies continue to drive limits on NOX
emission lower, other regulations are also driving down the permissible levels of NH3
that may be emitted into the atmosphere. Because of regulatory limits on ammonia
slip, the use of hydrocarbons and their oxygen derivatives for NOX reduction in an
SCR process is very attractive. Numerous catalysts have been suggested for this
purpose including zeolites, perovskites, and metals on metal oxide catalyst support.
However, existing catalyst systems have either low activity or narrow region of
working temperatures or low stability to water, which are detrimental to practical use.
U.S. Patent 6,703,343 teaches catalyst systems for use in NOX reduction. However,
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these catalyst systems require a specially synthesized metal oxide catalyst support
with very low level of impurities. Therefore there is a need for an effective catalyst
system to reduce NOX emissions, which system is stable and operable at a wide range
of temperatures.
BRIEF DESCRIPTION OF THE INVENTION
The present inventors have identified catalyst systems that are surprisingly effective
using commercially available metal oxide catalyst supports with common impurities
present. Thus, in one embodiment the present invention is a catalyst system for the
reduction of NOX, which catalyst system comprises a catalyst comprising a metal
oxide catalyst support, a catalytic metal oxide comprising at least one of gallium
oxide or silver oxide, and at least one promoting metal selected from the group
consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof. The
catalyst system further comprises a gas stream comprising an organic reductant
comprising oxygen.
Another embodiment of the present invention is a catalyst system for the reduction of
NOX, which catalyst system comprises a catalyst comprising (i) a metal oxide catalyst
support comprising alumina, (ii) at least one of gallium oxide or silver oxide present
in an amount in the range of from about 5 mole % to about 31 mole %; and (iii) a
promoting metal or a combination of promoting metals present in an amount in the
range of from about 1 mole % to about 22 mole % and selected from the group
consisting of silver; cobalt; molybdenum; tungsten; indium and molybdenum; indium
and cobalt; and indium and tungsten. The catalyst system further comprises a gas
stream comprising (A) water in a range of from about 1 mole % to about 12 mole %;
(B) oxygen in a range of from about 1 mole % to about 15 mole %; and (C) an
organic reductant comprising oxygen and selected from the group consisting of
methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl
carbonate and combinations thereof. The organic reductant and the NOX are present in
a carbon:NOx molar ratio from about 0.5:1 to about 24:1.
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In yet another embodiment the present invention is a method for reducing NOX, which
comprises the steps of: providing a gas mixture comprising NOX and an organic
reductant comprising oxygen; and contacting the gas mixture with a catalyst. The
catalyst comprises a metal oxide catalyst support, a catalytic metal oxide comprising
at least one of gallium oxide or silver oxide and at least one promoting metal selected
from the group consisting of silver, cobalt, molybdenum, tungsten, indium and
mixtures thereof.
In yet another embodiment the present invention is a method for reducing NOX, which
comprises the steps of: providing a gas stream comprising (A) NOX; (B) water from
about 1 mole % to about 12 mole %; (C) oxygen from about 1 mole % to about 15
mole %; and (D) an organic reductant comprising oxygen selected from the group
consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether,
dimethyl carbonate and combinations thereof; and contacting said gas stream with a
catalyst comprising (i) a metal oxide catalyst support comprising at least one member
selected from the group consisting of alumina, titania, zirconia, silicon carbide, and
ceria; (ii) at least one of gallium oxide or silver oxide in the range of from about 5
mole % to about 31 mole %; and (iii) a promoting metal or a combination of
promoting metals in the range of from about 1 mole % to about 22 mole % and
selected from the group consisting of silver; cobalt; molybdenum; tungsten; indium
and molybdenum; indium and cobalt; and indium and tungsten; wherein said organic
reductant and said NOX are present in a carbon:NOx molar ratio from about 0.5:1 to
about 24:1; and wherein said contact is performed at a temperature in a range of from
about 1000C to about 600°C and at a space velocity in a range of from about 5000 hr-1
to about 100000 hr1.
Various other features, aspects, and advantages of the present invention will become
more apparent with reference to the following description and appended claims.
DETAILED DESCRIPTION OF THE INVENTION
In the following specification and the claims, which follow, reference will be made to
a number of terms which shall be defined to have the following meanings. The
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singular forms "a", "an" and "the" include plural referents unless the context clearly
dictates otherwise.
In one embodiment the present invention comprises a catalyst system for the selective
reduction of NOX, which catalyst system comprises a catalyst and a reductant. The
catalyst comprises a metal oxide catalyst support, a catalytic metal oxide, and a
promoting metal. The reductant comprises an organic compound comprising oxygen.
The metal oxide catalyst support may comprise alumina, titania, zirconia, ceria,
silicon carbide or any mixture of these materials. Typically, the metal oxide catalyst
support comprises gamma-alumina with high surface area comprising impurities of at
least about 0.2% by weight in one embodiment and at least about 0.3% by weight
impurities in another embodiment. The metal oxide catalyst support may be made by
any method known to those of skill in the art, such as co-precipitation, spray drying
and sol-gel methods for example.
The catalyst also comprises a catalytic metal oxide. In one embodiment the catalytic
metal oxide comprises at least one of gallium oxide or silver oxide. In a particular
embodiment the catalyst comprises from about 5 mole % to about 31 mole % of
gallium oxide. In another particular embodiment the catalyst comprises from about 12
mole % to about 31 mole % of gallium oxide. In still another particular embodiment
the catalyst comprises from about 18 mole % to about 3.1 mole % of gallium oxide,
wherein in all cases mole percent is determined by dividing the number of moles of
catalytic metal by the total number of moles of the metal components in the catalyst,
including the catalyst support and any promoting metal present. In another particular
embodiment the catalyst comprises from about 0.5 mole % to about 31 mole % of
silver oxide. In another particular embodiment the catalyst comprises from about 10
mole % to about 25 mole % of silver oxide. In still another particular embodiment the
catalyst comprises from about 12 mole % to about 20 mole % of silver oxide, wherein
in all cases mole percent is determined by dividing the number of moles of catalytic
metal by the total number of moles of the metal components in the catalyst, including
the metal components of the catalyst support and any promoting metal present.
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The catalyst also comprises at least one promoting metal. The promoting metal may
comprise at least one of silver, cobalt, molybdenum, tungsten or indium. Additionally,
the promoting metal may also be a combination of more than one of these metals.
The catalyst typically comprises from about 1 mole % to about 22 mole % of the
promoting metal. In some embodiments the catalyst comprises from about 1 mole %
to about 12 mole % of the promoting metal and in some other embodiments from
about 1 mole % to about 7 mole % of the promoting metal. In one particular
embodiment the catalyst comprises from about 1 mole % to about 5 mole % of the
promoting metal. It should be appreciated that the term "promoting metal" is meant to
encompass elemental metals, metal oxides or salts of the promoting metal, such as
CO2O3 for example. In one particular embodiment wherein the catalytic metal oxide
comprises silver oxide, the catalyst system must further comprise at least one
promoting metal which is selected from the group consisting of cobalt, molybdenum,
tungsten, indium, and mixtures thereof.
The catalysts may be produced by an incipient wetness technique, comprising the
application of homogenous and premixed precursor solutions for catalytic metal oxide
and promoting metal contacted with the metal oxide catalyst support. The metal
oxide particles for the catalyst support are typically calcined before application of
precursor solution. In some embodiments a primary drying step at about 80°C to
about 120°C for about 1 -2 hours is followed by the main calcination process. The
calcination may be carried out at a temperature in the range of from about SOOT to
about 800°C. In some embodiments the calcination is carried out at a temperature in a
range of from about 650°C to about 725°C. In some embodiments the calcination is
done for about 2 hours to about 10 hours. In some other embodiments the calcination
is done for about 4 hours to about 8 hours. The particles are sifted to collect and use
those which are from about 0.1 to about 1000 micrometers in diameter. In one
embodiment the particle size ranges from about 2 micrometers to about 50
micrometers in diameter. Based on the surface area and total pore volume of the metal
oxide catalyst support particles, the desired loading of the catalyst may then be
calculated. As will be appreciated by those of ordinary skill in the art, the surface
area and porosity may be up to about 20-30% lower in the final catalyst product, as a
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result of catalyst loading. The loading of the catalyst is determined by the total pore
volume of the support, which is the volume of metal precursors that can be loaded by
incipient wetness. The precursor loading is chosen such that the amount of metal is
typically less than a monolayer of the active metal oxide on the metal oxide catalyst
support. In some embodiments twice the pore volume is used as the total volume of
precursor to load and the metal loading is taken in the range of from about 1 millimole
to about 5 millimoles of the mixture of catalytic metal oxide and promoting metal per
gram of metal oxide catalyst support.
In the subsequent steps of preparing the catalyst, precursor solutions of the catalytic
metal oxide and, one or more promoting metals may be prepared. Precursor solutions
may be prepared in aqueous media, in hydrophilic organic media, or in a mixture
thereof. Hydrophilic organic media comprise carboxylic acids, alcohols and mixtures
thereof such as, but not limited to, acetic acid or ethanol. The solutions are typically
made by mixing solvent with metal salts, such as, but not limited to, metal nitrates,
citrates, oxalates, acetylacetonates, molybdates, or benzoates, in an amount to create a
solution of appropriate molarity based on the desired catalyst composition. In some
embodiments the metal salt is a molybdenum heteropoly anion or ammonium
molybdate. The methods used for preparing the catalyst system are known in the art
and include depositing metal oxide catalyst support in a honey-comb support in a
wash coating method or extruding in a slurry into a desired form. The purity of the
metal precursors for both catalytic metal oxide and promoting metal is in the range of
from about 95 % to about 99.999 % by weight. In one embodiment, all the metal
precursors are mixed together and are as homogeneous as possible prior to addition to
the metal oxide catalyst support. In some other embodiments different metal
precursors are added sequentially to the metal oxide catalyst support. In one
embodiment, the desired volume of the precursor solution is added to coat the metal
oxide catalyst support and create a catalyst with the desired final catalyst loading.
Once the metal salt solution or solutions have been added to the metal oxide catalyst
support, the catalyst may optionally be left to stand for a period of time, in some
embodiments about 6 to 10 hours. The catalyst is then dried for a period of time at a
desired temperature. In a particular embodiment the catalyst may be dried under a
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vacuum, optionally while a nitrogen stream is passed over the mixture. Finally, the
catalyst may be calcined at a desired temperature and for a desired time to create the
final catalyst product.
r
Catalysts according to exemplary embodiments of the present invention may be
created using either a manual or an automated process. Typically, a manual process is
used for the preparation of catalysts of a larger mass, such as about 1 to about 20
grams (g) for example. An automated process is typically used when the catalysts are
of a smaller mass, such as about 5 milligrams (mg) to about 100 mg, for example.
Generally, manual and automated processes for preparation of the catalyst are similar
with the exception that an automated process involves automated measuring and
dispensing of the precursor solutions to the metal oxide catalyst support.
The reductant for use in the catalyst system of exemplary embodiments of the present
invention comprises an organic compound comprising oxygen. Said organic
compounds comprising oxygen are fluid, either as a liquid or gas, such that they may
flow through the catalyst when introduced into an effluent gas stream for use in a
catalyst system for the reduction of NOX. Typically, hydrocarbons comprising oxygen
of less than about 16 carbon atoms will be fluid, although hydrocarbons comprising
oxygen with higher numbers of carbon atoms may also be fluid, for example,
depending on the chemical structure and temperature of the gas stream. The organic
compounds comprising oxygen suitable for use as reductants typically comprise a
member selected from the group consisting of an alcohol, an ether, an ester, a
carboxylic acid, an aldehyde, a ketone, a carbonate and combinations thereof. In
some embodiments the organic compounds comprising oxygen suitable for use as
reductants comprise at least one functional group selected from the group consisting
of hydroxy, alkoxy, carbonyl, carbonate and combinations thereof. Some non-limiting
examples of organic compounds comprising oxygen suitable for use as reductants
comprise methanol, ethyl alcohol, 1-butanol, 2-butanol, 1-propanol, iso-propanol,
dimethyl ether, dimethyl carbonate and combinations thereof.
The catalyst system may be used in conjunction with any process or system in which
it may be desirable to reduce NOX emissions, such as a gas turbine; a steam turbine; a
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boiler; a locomotive; or a transportation exhaust system, such as, but not limited to, a
diesel exhaust system. The catalyst system may also be used in conjunction with
systems involving generating gases from burning coal, burning volatile organic
compounds (VOC), or in the burning of plastics; or in silica plants, or in nitric acid
plants. The catalyst is typically placed at a location within an exhaust system where it
will be exposed to effluent gas comprising NOX. The catalyst may be arranged as a
packed or fluidized bed reactor, coated on a monolithic, foam, mesh or membrane
structure, or arranged in any other manner within the exhaust system such that the
catalyst is in contact with the effluent gas.
As will be appreciated by those ordinarily skilled in the art, although catalytic
reactions are generally complex and involve many steps, the overall basic selective
catalytic reduction reaction process for the reduction of NOX is believed to occur as
follows:
NOX + O2 + organic reductant -> N2 + CO2 + H2O (1)
The effluent gas stream usually comprises air, water, CO, CO2, NOX, and may also
comprise other impurities. Additionally, uncombusted or incompletely combusted fuel
may also be present in the effluent gas stream. The organic reductant is typically fed
into the effluent gas stream to form a gas mixture, which is then fed through the
catalyst. Sufficient oxygen to support the NOX reduction reaction may already be
present in the effluent gas stream. If the oxygen present in the gas mixture is not
sufficient for the NOX reduction reaction, additional oxygen gas may also be
introduced into the effluent gas stream in the form of oxygen or air. In some
embodiments the gas stream comprises from about 1 mole % to about 21 mole % of
oxygen gas. In some other embodiments the gas stream comprises from about 1 mole
% to about 15 mole % of oxygen gas.
One advantage of embodiments of the present invention is that the reduction reaction
may take place in "reductant lean" conditions. That is, the amount of reductant added
to the effluent gas to reduce the NOX is generally low. Reducing the amount of
reductant to convert the NOX to nitrogen may provide for a more efficient process that
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has decreased raw material costs. The molar ratio of reductant to NOX is typically in a
range of from about 0.25:1 to about 6:1. In other embodiments the ratio is typically
such that the ratio of carbon atoms in the reductant is about 0.5 to about 24 moles per
mole of NOX. In some other embodiments the organic reductant and the NOX are
present in a carbon:NOx molar ratio in a range of from about 0.5:1 to about 15:1. In a
particular embodiment the organic reductant and the NOX are present in a carbon:NOx
molar ratio in a range of from about 0.5:1 to about 8:1.
The reduction reaction may take place over a range of temperatures. Typically, the
temperature may range in one embodiment from about 100°C to about 600°C, in
another embodiment from about 200°C to about 500°C and in still another
embodiment from about 350°C to about 450°C.
The reduction reaction may take place under conditions wherein the gas mixture is
configured to have a space velocity in one embodiment in a range of from about 5000
reciprocal hours (hr-1) to about 100000 hr-1, in another embodiment in a range of from
about 8000 hr-1 to about 50000 hr-1 and in still another embodiment in a range of from
about 8000 hr-1 to about 40000 hr-1.
Exemplary embodiments of the catalyst system may also advantageously be used in
wet conditions. In particular embodiments NOX reduction accomplished using
exemplary embodiments of the present invention may be effective in effluent gas
streams comprising water. In some embodiments the gas stream comprises from about
1 mole % to about 12 mole % of water and in some other embodiments from about 2
mole % to about 10 mole % of water.
Without further elaboration, it is believed that one skilled in the art can, using the
description herein, utilize the present invention to its fullest extent. The following
examples are included to provide additional guidance to those skilled in the art in
practicing the claimed invention. The examples provided are merely representative of
the work that contributes to the teaching of the present application. Accordingly,
these examples are not intended to limit the invention, as defined in the appended
claims, in any manner.
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EXAMPLES
Catalysts were prepared and used in combination with reductants in accordance with
exemplary embodiments of the present invention. The conversion of the NOX was
analyzed over a variety of experimental conditions, including varying catalyst
compositions, reductants, reaction temperatures, and reductant to NOx ratios.
In the following examples catalyst samples were prepared each having a gamma-
alumina catalyst support commercially available from Saint-Gobain NorPro of Stow,
Ohio. The alumina catalyst support had a purity of 99.5% to 99.7%. The alumina
support was first calcined at 725°C for 6 hours in presence of an oxidant. The oxidant
may be air or an oxidant gas comprising about 1 % to about 21% of oxygen in
nitrogen. The alumina particles were then sifted to collect catalyst support having a
particle size diameter of from about 450 micrometers to about 1000 micrometers.
Prior to loading, the catalyst support had a surface area of about 240 square meters per
gram (m2/g) and a pore volume of 0.796 milliliters per gram (mL/g).
Gallium was used as the metal for the catalytic metal oxide added to the alumina. The
gallium was added in a soluble form to wet the alumina support and was made from a
solution of gallium nitrate having the formula Ga(NO3)3 • 6H2O. The solution was
made by combining deionized water with gallium nitrate having a purity of 99.999%
(metals basis) obtained from Alfa-Aesar of Ward Hill, Massachusetts. Millipore
water having a resistivity of 18 megaohm-centimeters was employed in all operations.
For the promoting metal an aqueous solution of the nitrate salt of the desired metal(s)
also having a purity of 99.999% (metals basis) and obtained from Alfa-Aesar was
added to the alumina support. All the metal precursors were mixed together and were
as homogeneous as possible prior to addition to the alumina support. The catalysts
were left to stand for 6 to 10 hours and were then dried under a dynamic vacuum with
a nitrogen influx for 4 to 5 hours at 80°C. Finally, the dried catalyst was heat treated.
The heat profile for this treatment began with an increase from 25°C to 110°C at
1.4°C per minute. The catalyst was held at 110°C for 1.5 hours, after which the
temperature was ramped at 5°C per minute to a value of 650°C. The catalyst was held
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6 hours at this temperature and then allowed to cool over a period of about 4 to 6
hours.
Catalysts were tested in a 32-tube high-throughput heterogeneous catalyst-screening
micro-reactor. The reactor was a heated, common headspace gas distribution
manifold that distributed a reactant stream equally via matched capillaries to parallel
reactor tubes. The manifold had heated capabilities, allowing pre-heating of the
reactant stream and vaporization of liquid reactants prior to distribution. The entire
heated manifold assembly was mounted on a vertical translation stage, raised and
lowered via pneumatic pressure. Reactor tubes were inserted in a gold-coated 10
centimeter (cm) thick insulated copper reactor block (dimension 13.5 cm x 25 cm),,
which was electrically heated to vary temperature between 200°C to 650°C.
Chemically inert KALREZ™ o-rings available from DuPont of Wilmington,
Delaware, served as viscoelastic end-seals on either end of each reactor tube. Reactor
tubes were made of INCONEL 600 ™ tubing with 0.635 cm outside diameter and
0.457 cm internal diameter, available from Inco Alloys/Special Metals of Saddle
Brook, New Jersey. The tubes were free to slide vertically through the gold-coated
copper heating block. Each tube contained a quartz wool frit, on which the catalyst
samples of about 0.050 g were placed in the center of each of the tubes through which
a reactant stream of a blended gas mixture comprising NOX and reductant simulating
an effluent gas stream was passed. A single bypass tube was used to ensure equal
flow through each of the 32 testing tubes. The fittings were connected to a
distribution manifold for delivery of the blended gas mixture. The components of the
blended gas mixture were fed to a common mixing manifold using electronic mass
flow controllers, and then routed to the distribution manifold. The pressure in the
distribution manifold was maintained at about 275.8 kilopascals (kPa). Reactor
temperature and flow control were fully automated.
Once loaded in the tubes, the catalysts were heat-treated under airflow as described
herein above and then reacted with the blended gas mixture. The reactor effluent was
sent to heated sampling valves that selected tubes in series and fed the continuous
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stream to a chemiluminescent analyzer. Any stream that was not routed to the
analytical device was routed to a common vent.
Switching valves for routing gases were computer controlled and actuated in a pre-
determined time-based sequence. The chemiluminescent analyzer was connected to a
computer-based data-logging system. Data corresponding to reactor tube effluent
composition were time-stamped and stored. Data from the bypass tube were also
stored as a reference to the inlet composition of the catalyst reactor tubes. This
permitted the combination of data to determine activity and selectivity of each catalyst
sample.
For NOX reduction testing the reactant stream of the blended gas mixture comprised
reductant, about 200 ppm NOX, 12% by volume oxygen, 7% by volume water and the
balance nitrogen. The type and amount of reductant in the stream varied depending
on the experiments being conducted. The flow rate of the blended gas mixture
through each of the tubes was 33 standard cubic centimeters per minute (sccm) per
tube.
Table 1 shows the compositions of the catalyst samples prepared, with compositions
expressed in mole percent of each promoting metal and/or catalytic metal present in
the catalyst. The balance of the composition was alumina from the alumina catalyst
support. Mole percent was determined for each component by dividing the number of
moles of that component by the total number of moles of the metal components in the
catalyst, including the metal components of the metal oxide catalyst support. The
abbreviation "C.Ex." means Comparative Example. Comparative example 1 consists
only of the alumina support.
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TABLE 1

Example Ga In Ag Co Mo w
C.Ex. 1 0 0 0 0 0 0
C.Ex. 2 29 0 0 0 0 0
C.Ex. 3 0 2 0 0 0 0
CEx. 4 0 4 0 0 0 0
C.Ex. 5 0 0 2 0 0 0
C.Ex. 6 0 0 5 0 0 0
C.Ex. 7 27 2 0 0 0 0
Ex.1 27 0 2 0 0 0
Ex.2 25 0 4 0 0 0
Ex.3 27 0 0 2 0 0
Ex.4 25 0 0 4 0 0
Ex.5 25 2 0 2 0 0
Ex.6 22 3 0 3 0 0
Ex.7 27 0 0 0 2 0
Ex.8 25 0 0 0 5 0
Ex.9 22 0 0 0 8 0
Ex.10 22 3 0 0 3 0
Ex.11 21 6 0 0 1 . 0
Ex.12 27 0 0 0 0 2
Ex.13 25 0 0 0 0 4
Ex.14 20 0 0 0 0 8
Ex.15 22 6 0 0 0 1
Ex.16 21 3 0 0 0 3
A first set of experiments was conducted in which various catalyst samples were
prepared and tested with various reductants using the described testing procedure at
350°C. The results in Table 2 show the percentage of NOX converted for each of the
catalyst systems. The example and comparative example numbers in Table 2
correspond to the catalyst compositions in the examples and comparative examples of
Table 1. Although the molar ratio of reductant to NOX varied with the reductant used,
the molar ratio of carbon:NOx was generally equal to about 2:1 for each of the
experimental systems. The abbreviation "NBA" means 1-butanol.
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TABLE 2

Reductants
Example MeOH EtOH i-PrOH NBA
C.Ex. 1 12 35 30 35
C.Ex. 2 18 32 33 31
C.Ex. 3 29 35 28 33
C.Ex. 4 26 34 43 32
C.Ex. 5 6 24 66 42
C.Ex. 6 7 14 36 21
Ex.1 12 59 97 55
Ex.2 2 14 30 19
Ex.3 15 34 31 30
Ex.4 43 56 25 46
Ex.5 42 46 28 41
Ex.6 34 39 33 39
As shown in Table 2, Example 1 having a combination of gallium oxide as a catalytic
metal oxide and silver as a promoting metal showed particularly good results using
reductants such as ethanol, iso-propanol and 1-butanol. Example 4 comprising
gallium and cobalt showed good performance with methanol, ethanol and NBA.
Examples 5 and 6 comprising cobalt, indium and gallium also showed good
performance with methanol, ethanol, and 1 -butanol.
A second set of experiments was conducted in which various catalyst samples were
prepared and tested with various reductants using the described testing procedure at
400°C. The results in Table 3 show the percentage of NOX converted for each of the
catalyst systems. The example and comparative example numbers in Table 3
correspond to the catalyst compositions identified in the examples and comparative
examples of Table 1. Although the molar ratio of reductant to NOX varied with the
reductant used, the molar ratio of carbon:NOx was generally equal to about 6:1 for
each of the experimental systems. The abbreviations "DMC", IPA", and "NBA"
mean dimethyl carbonate, iso-propyl alcohol, and 1-butanol, respectively.
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TABLE 3

Catalyst Composition Reductant
Example Ga In Ag Co Mo w MeOH DMC EtOH IPA NBA
C.Ex. 2 29 0 0 0 0 0 20 38 57 55 57
C.Ex. 3 0 2 0 0 0 0 18 34 55 61 56
C.Ex. 5 0 0 2 0 0 0 21 30 95 96 83
C.Ex. 7 27 2 0 0 0 0 28 48 62 54 57
Ex.3 27 0 0 2 0 0 17 79 49 42 37
Ex.6 22 3 0 3 0 0 18 49 40 40 33
Ex.7 27 0 0 0 2 0 28 44 60 52 56
Ex.8 25 0 0 0 5 0 34 54 76 70 65
Ex.9 22 0 0 0 8 0 50 77 44 31 41
Ex.10 22 3 0 0 3 0 35 62 47 33 42
Ex.11 21 6 0 0 1 0 25 25 65 28 21
Ex.12 27 0 0 0 0 2 37 55 19 22 68
Ex.13 25 0 0 0 0 4 53 32 28 24 21
Ex.14 20 0 0 0 0 8 65 36 30 31 29
Ex.15 22 6 0 0 0 1 24 58 50 13 55
Ex.16 21 3 0 0 0 3 41 64 60 22 61
While all of the catalyst samples showed good or better performance compared with
comparative examples, example 8 having 5 mole % molybdenum and 25 mole %
gallium showed good results with all of the five oxygenated reductants. In general the
catalyst systems in accordance with exemplary embodiments of the present method
were successful in reducing some NOX in each case.
A third set of experiment was conducted in which methanol was tested as a reductant
at 400°C in presence of a gas mixture comprising 200 ppm NOX, 4% water, and 13%
O2 and the balance nitrogen at a nominal space velocity of 28,000 hr1. The catalyst
compositions along with the catalyst activity for each experiment are given in Table 4.
The balance of moles catalyst comprises the metal oxide catalyst support. Although
the molar ratio of reductant to NOX varied with the reductant used, the molar ratio of
carbon:NC\ was generally equal to about 6:1 for each of the experimental systems.
The catalyst activity is expressed in moles of NOX converted to N2 per gram of
catalyst per hour.
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TABLE 4

Example Catalyst Reductant
Ga Ag In MeOH
Ex.17 6 6 19 5.2E-06
Ex.18 6 13 13 1.0E-05
Ex.19 6 19 6 1.6E-05
Ex.20 13 6 13 5.2E-06
Ex.21 0 19 13 2.0E-05
Ex.22 0 13 19 5.9E-07
Ex.23 29 2 0 8.4E-08
Ex.24 0 16 16 1.7E-05
Ex.25 9 11 11 1.1E-05
Ex.26 5 16 10 1.6E-5
C.Ex. 8 31 0 0 6.3E-07
Various embodiments of this invention have been described in fulfillment of the
various needs that the invention meets. It should be recognized that these
embodiments are merely illustrative of the principles of various embodiments of the
present invention. Numerous modifications and adaptations thereof will be apparent
to those skilled in the art without departing from the spirit and scope of the present
invention. Thus, it is intended that the present invention cover all suitable
modifications and variations as come within the scope of the appended claims and
their equivalents.
16

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What is claimed is:
1. A catalyst system for the reduction of NOX comprising:
a catalyst comprising a metal oxide catalyst support, a catalytic metal oxide
comprising at least one of gallium oxide or silver oxide, and at least one promoting
metal selected from the group consisting of silver, cobalt, molybdenum, tungsten,
indium and mixtures thereof; and
a gas stream comprising an organic reductant comprising oxygen.
2. The catalyst system of claim 1, wherein said metal oxide catalyst support
comprises at least one member selected from the group consisting of alumina, titania,
zirconia, ceria, silicon carbide and mixtures thereof.
3. The catalyst system of claim 1, wherein said catalytic metal oxide comprises
gallium oxide in a range of from about 5 mole % to about 31 mole %.
4. The catalyst system of claim 1, wherein said catalytic metal oxide comprises
gallium oxide in a range of from about 18 mole % to about 31 mole %.
5. The catalyst system of claim 1, wherein said catalytic metal oxide comprises
silver oxide in the range of from about 0.5 mole % to about 31 mole %.
6. The catalyst system of claim 1, wherein said catalyst comprises said
promoting metal in a range of from about 1 mole % to about 22 mole %.
7. The catalyst system of claim 1, wherein said catalyst comprises said
promoting metal in a range of from about 1 mole % to about 7 mole %.
8. The catalyst system of claim 1, wherein the catalytic metal oxide comprises
gallium oxide and the promoting metal comprises silver or the combination of indium
and silver.
9. The catalyst system of claim 1, wherein the catalytic metal oxide comprises
silver oxide and the promoting metal comprises of indium.
17

146984
10. The catalyst system of claim 1, wherein said organic reductant is selected from
the group consisting of an alcohol, an ether, an ester, a carboxylic acid, an aldehyde, a
ketone, a carbonate and combinations thereof.
11. The catalyst system of claim 1, wherein said organic reductant is selected from
the group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol,
dimethyl ether, dimethyl carbonate and combinations thereof.
12. The catalyst system of claim 1, wherein said organic reductant and said NOX
are present in a carbon:NOx molar ratio from about 0.5:1 to about 24:1.
13. The catalyst system of claim 1, wherein said organic reductant and said NOX
are present in a carbon:NOx molar ratio from about 0.5:1 to about 8:1
14. The catalyst system of claim 1, wherein said gas stream further comprises
water in a range of from about 1 mole % to about 12 mole %.
15. The catalyst system of claim 1, wherein said gas stream further comprises
oxygen gas in a range of from about 1 mole % to about 21 mole %.
16. The catalyst system of claim 1, wherein NOX is present in effluent gas from a
combustion source, said combustion source comprising at least one of a gas turbine, a
boiler, a locomotive, a transportation exhaust system, coal burning, plastics burning,
volatile organic compound burning, a silica plant, or a nitric acid plant.
17. A catalyst system for the reduction of NOX comprising:
a catalyst comprising (i) a metal oxide catalyst support comprising alumina, (ii) at
least one of gallium oxide or silver oxide present in an amount in the range of from
about 5 mole % to about 31 mole %; and (iii) a promoting metal or a combination of
promoting metals present in an amount in the range of from about 1 mole % to about
22 mole % and selected from the group consisting of silver; cobalt; molybdenum;
tungsten; indium and molybdenum; indium and cobalt; and indium and tungsten; and
a gas stream comprising (A) water in a range of from about 1 mole % to about 12
mole'%; (B) oxygen in a range of from about 1 mole % to about 15 mole %; and (C)
18

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an organic reductant comprising oxygen and selected from the group consisting of
methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl
carbonate and combinations thereof;
wherein said organic reductant and said NOX are present in a carbon:NOx molar ratio
from about 0.5:1 to about 24:1.
18. A method for reducing NOX, which comprises the steps of:
providing a gas mixture comprising NOX and an organic reductant comprising
oxygen; and
contacting said gas mixture with a catalyst, wherein said catalyst comprises a metal
oxide catalyst support, a catalytic metal oxide comprising at least one of gallium
oxide or silver oxide, and at least one promoting metal selected from the group
consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof.
19. The method of claim 18, wherein said contact is at a temperature in a range of
from about 100 °C to about 600°C.
20. The method of claim 18, wherein said contact is at a temperature in a range of
from about 200°C to about 500°C.
21. The method of claim 18, wherein said contact is performed at a space velocity
in a range of from about 5000 hr"1 to about 100000 hr"1.
22. The method of claim 18, wherein said metal oxide catalyst support comprises
at least one of alumina, titania, zirconia, silicon carbide or ceria.
23. The method of claim 18, wherein said catalytic metal oxide comprises gallium
oxide in the range of from about 5 mole % to about 31 mole %.
24. The method of claim 18, wherein said catalyst comprises said promoting metal
from about 1 mole % to about 22 mole %.
19

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25. The method of claim 18, wherein said organic reductant is selected from the
group consisting of an alcohol, an ether, an ester, a carboxylic acid, an aldehyde, a
ketone, a carbonate and combinations thereof.
26. The method of claim 18, wherein said organic reductant is selected from the
group consisting of methanol, ethyl alcohol, butyl alcohol, propyl alcohol, dimethyl
ether, dimethyl carbonate and combinations thereof.
27. The method of claim 18, wherein said organic reductant and said NOX are
present in a carbon:NOx molar ratio from about 0.5:1 to about 24:1.
28. The method of claim 18, wherein said gas stream comprises water from about
1 mole % to about 12 mole %.
29. The method of claim 18, wherein said gas stream comprises oxygen from
about 1 mole % to about 21 mole %.
30. The method of claim 18, wherein NOX is present said effluent gas from a
combustion source, said combustion source comprising at least one of a gas turbine, a
boiler, a locomotive, a transportation exhaust system, coal burning, plastics burning,
volatile organic compound burning, a silica plant, or a nitric acid plant.
31. A method for reducing NOX, which comprises the steps of:
providing a gas stream comprising (A) NOx; (B) water from about 1 mole % to about
12 mole %; (C) oxygen from about 1 mole % to about 15 mole %; and (D) an organic
reductant comprising oxygen selected from the group consisting of methanol, ethyl
alcohol, butyl alcohol, propyl alcohol, dimethyl ether, dimethyl carbonate and
combinations thereof; and
contacting said gas stream with a catalyst comprising (i) a metal oxide catalyst
support comprising at least one member selected from the group consisting of
alumina, titania, zirconia, silicon carbide, and ceria; (ii) at least one of gallium oxide
or silver oxide in the range of from about 5 mole % to about 31 mole %; and (iii) a
promoting metal or a combination of promoting metals in the range of from about 1
20

146984
mole % to about 22 mole % and selected from the group consisting of silver; cobalt;
molybdenum; tungsten; indium and molybdenum; indium and cobalt; and indium and
tungsten;
21
wherein said organic reductant and said NOX are present in a carbon:NOX molar ratio
from about 0.5:1 to about 24:1; and wherein said contact is performed at a
temperature in a range of from about 100°C to about 600°C and at a space velocity in
a range of from about 5000 hr-1 to about 100000 hr-1.

A catalyst system for the reduction of NOx comprises a catalyst comprising a metal
oxide catalyst support, a catalytic metal oxide comprising at least one of gallium
oxide or silver oxide, and at least one promoting metal selected from the group
consisting of silver, cobalt, molybdenum, tungsten, indium and mixtures thereof. The
catalyst system further comprises a gas stream comprising an organic reductant
comprising oxygen. A method for reducing NOx utilizing the said catalyst system is
also provided.

Documents:

01878-kolnp-2007-abstract.pdf

01878-kolnp-2007-assignment.pdf

01878-kolnp-2007-claims.pdf

01878-kolnp-2007-correspondence others 1.1.pdf

01878-kolnp-2007-correspondence others 1.2.pdf

01878-kolnp-2007-correspondence others.pdf

01878-kolnp-2007-description complete.pdf

01878-kolnp-2007-form 1.pdf

01878-kolnp-2007-form 2.pdf

01878-kolnp-2007-form 3.pdf

01878-kolnp-2007-form 5.pdf

01878-kolnp-2007-gpa.pdf

01878-kolnp-2007-international publication.pdf

01878-kolnp-2007-international search report.pdf

01878-kolnp-2007-pct request form.pdf

01878-kolnp-2007-priority document.pdf

1878-KOLNP-2007-(15-02-2012)-AMANDED CLAIMS.pdf

1878-KOLNP-2007-(15-02-2012)-CORRESPONDENCE.pdf

1878-KOLNP-2007-(15-02-2012)-DESCRIPTION (COMPLETE).pdf

1878-KOLNP-2007-(15-02-2012)-FORM 1.pdf

1878-KOLNP-2007-(15-02-2012)-FORM 2.pdf

1878-KOLNP-2007-(15-02-2012)-FORM 3.pdf

1878-KOLNP-2007-(15-02-2012)-OTHERS.pdf

1878-KOLNP-2007-(15-02-2012)-PETITION UNDER RULE 137.pdf

1878-KOLNP-2007-(24-04-2012)-CORRESPONDENCE.pdf

1878-KOLNP-2007-(24-04-2012)-FORM-3.pdf

1878-KOLNP-2007-(28-11-2011)-CORRESPONDENCE.pdf

1878-KOLNP-2007-(28-11-2011)-CORRESPONDENCE1.pdf

1878-KOLNP-2007-(28-11-2011)-FORM-13.pdf

1878-KOLNP-2007-(28-11-2011)-PA.pdf

1878-kolnp-2007-form 18.pdf

1878-KOLNP-2007-FORM 3-1.1.pdf

1878-KOLNP-2007-REPLY TO EXAMINATION REPORT.pdf

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Patent Number

254795

Indian Patent Application Number

1878/KOLNP/2007

PG Journal Number

51/2012

Publication Date

21-Dec-2012

Grant Date

19-Dec-2012

Date of Filing

25-May-2007

Name of Patentee

GENERAL ELECTRIC COMPANY

Applicant Address

1 RIVER ROAD, SCHENECTADY, NY

Inventors:

#	Inventor's Name	Inventor's Address
1	REDLINE, JENNIFER KATHLEEN	1396 PARKWOOD BOULEVARD, SCHENECTADY, NY 12308
2	BUDESHEIM, ERIC GEORGE	1, ANGLERS COURT, WYNANTSKILL, NY 12198
3	CHEN, KAIDONG	1009 CLAY STREET, ALBANY, CA 94706
4	BUDDLE, STANLEE TERESA	16 W 12TH AVENUE, GLOVERSVILLE, NY 12078
5	MALE, JONATHAN LLOYD	345 STATE ROUTE 443, SCHOHARIE, NY 12157
6	PALMATIER, ALISON LIANA	64 MINER ROAD, PORTER CORNERS, NY 12859
7	ROCHA, TERESA GROCELA	37 CASTLE PINES, CLIFTON PARK, NY 12065
8	HANCU, DAN	19 AMITY POINTE COURT, CLIFTON PARK, NY 12065
9	WARNER, GREGORY LEE	731 CENTRAL PARKWAY, SCHENECTADY, NY 12309
10	SOLOVEICHIK, GRIGORLI LEV	37 LAURA DRIVE, LATHAM, NY 12110 .

PCT International Classification Number

B01J 23/08

PCT International Application Number

PCT/US2005/044470

PCT International Filing date

2005-12-08

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	11/022,901	2004-12-22	U.S.A.