MXPA97004907A - Catalytic oxidation catalyst and method for paracontrolling coal, co and organic emissions halogen - Google Patents

Abstract

The present invention relates to: A catalyst and a method for treating gas streams containing halogenated organic compounds, non-halogenated organic compounds, non-halogenated organic compounds, carbon monoxide or mixtures thereof and particularly gas streams containing organobromide. The catalyst comprises at least one metal of the platinum group, zirconium oxide and at least cerium or cobal manganese oxide

Description

CATALYZER DB CATALYTIC OXIDATION AND METHOD FOR CQW RQLAE EMISSIONS PE COY, CQ and ORGÁ ICOS HAQgSWAXiOg pggcRipciQw PIE The ttwmciom This invention relates to a novel catalyst and process for the catalytic oxidation of gaseous gaseous emissions, in particular gaseous carbonaceous emissions that include halogen-containing compounds and more particularly organobromides. The treatment of gaseous emissions containing volatile organic compounds and carbon monoxide has been of increasing interest in recent years. Thermal incineration, catalytic oxidation and adsorption are commonly used to remove these contaminants. Thermal incineration requires high operating temperatures and high capital cost facilities. If the gas stream also includes halogenated compounds, thermal incineration can give off toxic halogenated compounds under certain operating conditions. In some cases, adsorption by adsorbents such as carbon is an alternative. However, this procedure does not destroy the contaminants, but simply concentrates them. In addition, the adsorption efficiency can be adversely impacted by fluctuating concentrations of the gaseous components. Catalytic oxidation is an economical and energy efficient way to destroy gaseous organic emissions. It operates at significantly lower temperatures and shorter residence times than thermal incineration and requires smaller reactors made of less expensive materials. Methods for catalytic oxidation of halogenated organic and non-halogenated organic compounds are well known in the art. For example in the article by G. C. Bond and N. Sadeghi in "Catalized Destruction of Chlorinated Hydrocarbons" (Applied Chem. Biotechnol .. 1975, 25,241-248, reports that chlorinated hydrocarbons are converted into HCl and C02 over platinum into gamma catalyst alumina US Patent Nos. 3,972,979 and 4,053,557 describe the decomposition of halogenated hydrocarbons by oxidation on chromium oxide or platinum supported on boehmite US Patents Nos. 4,059,675 and 4,059,683 describe methods for decomposing halogenated organic compounds using catalysts that they contain ruthenium, ruthenium-palladium and platinum, respectively in the presence of an oxidizing agent at a temperature of at least 350 * C. The article by James J. Spivy, "Complete Catalytic Oxidation of Volatile Organics" (Complete catalytic oxidation of volatile organic ), Ind. Eng. Chem. Res. 1987, 26, 2165-2180, is a review of the literature dealing with oxidation Heterogeneous catalytic conversion of volatile organic compounds. The article by S. Chatterjee and H.L. Green, "Oxidative catalysis by Chlorinated Hydrocarbons * and Metal-Load Acid Catalysts" (oxidative catalysis by chlorinated hydrocarbons by metal-charging acid catalysts) Journal of Catalysisr 1991, 130, 76-85, reports in a study of catalytic oxidation of Methylene chloride in air using supported zeolite catalysts HY, Cr-Y and Ce-Y. The article by A. Melchor, E. E. Garbo s i, M.V.

Michel-Vital Mathia and Primet, "Physicochemical Properties and Isomerization Activity of Chlorinated Pt / Al203 catalyst " (Physical chemical properties and isomerization activity of chlorinated Pt / Al203 catalyst), J. Chem Soc., Faraday Trans. 1, 1986, 82, 3667-3679, reports that the chlorination of alumina leads to a very acidic solid due to an improvement in strength or strength and number of strong Lewis sites. The chlorination treatment improves the sintering of platinum. The patent of the U.S.A. No. 4,983,366 discloses a method for the catalytic conversion of waste gases containing hydrocarbons and carbon monoxide by passing waste or waste gases through a first zone containing a catalyst such as aluminum oxide, silicon dioxide, silicate of aluminum and / or a zeolite optionally containing oxidic compounds or barium, manganese, copper, chromium and nickel, and then through a second zone containing a catalyst such as platinum and / or platinum and / or palladium or platinum and rhodium .

PCT International Application No. PCT / US90 / 02386 describes a catalytic process for converting or destroying organic compounds including organohalogen compounds, which utilizes a catalyst containing titanium oxide as a catalyst component. The preferred catalyst also contains vanadium oxide, tungsten oxide, tin oxide and at least one noble metal selected from the group consisting of palladium and rhodium platinum, characterized in that the vanadium oxide, tungsten oxide and noble metals are uniformly dispersed in the titanium oxide. The patent of the U.S.A. No. 5,283,041 (commonly assigned to the assignee of the present invention) herein incorporated by reference, discloses an oxidation catalyst for treating a gas stream containing compounds selected from the group consisting of halogenated organic compounds, other organic compounds and mixtures thereof. The catalyst comprises a core material of zirconium oxide and one or more oxides of manganese, cerium or cobalt, with dispersed vanadium oxide therein, and may further include a metal of the platinum group dispersed in the core material. There is still a need for catalyzing the oxidative destruction of halogenated organic compounds, non-halogenated and carbon monoxide, to provide improved operating efficiencies at lower operating temperatures. This is particularly true for the treatment of gas streams containing organobromides that have been found to be particularly difficult to incinerate. This invention relates to catalysts and processes for the treatment of gas streams containing compounds selected from the group consisting of halogenated organic compounds, non-halogenated organic compounds, carbon monoxide and mixtures thereof. Catalysts and processes are particularly convenient for treating gas streams that additionally contain one or more elemental halogens, which specifically include gas streams in which these elemental halogens are initially present or formed during the catalytic treatment of halogenated organic compounds. In particular embodiments, the gas streams contain brominated organic compounds and elemental bromine, either initially present or formed during the catalytic treatment. One embodiment of this invention is a catalyst for treating a gas stream. It contains compounds selected from the group consisting of halogen-containing compounds, organic compounds that are not halogenated, carbon monoxide (CO) and mixtures thereof. The catalyst useful in the practice of this invention comprises one or more metals of the platinum group, zirconium oxide and at least one oxide selected from the group consisting of manganese oxide, cerium oxide and cobalt oxide.

Another embodiment of this invention is a process for treating a gas stream containing compounds selected from the group consisting of halogen-containing compounds, non-halogenated organic compounds, carbon monoxide and mixtures thereof. The method comprises contacting this gas stream at a temperature of about 150"C to 550 ° C, with a catalyst comprising one or more metals of the platinum group, zirconium oxide and at least one oxide selected from the group consisting of manganese oxide. , cerium oxide and cobalt oxide, in the presence of an effective amount of oxygen, to facilitate the oxidation reactions In particular embodiments of the catalyst and process of this invention, the gas stream contains halogens in elemental form such as Br 2 or Cl2 or contains halogenated organic compounds which form these elemental halogens during the catalytic treatment.The catalyst and the process are particularly convenient for use with gas streams, wherein the elemental halogen or halogen of the halogenated compound is bromine. present invention, a gas stream containing an organic compound Brominated, which may be in combination with non-brominated organic compounds, carbon monoxide or mixtures thereof, is treated with a catalyst comprising at least one metal of the platinum group, zirconium oxide and jpanganese oxide.

In this process, at least some bromine in the brominated organic compounds is converted to elemental bromine. In general, this catalytic oxidation process converts its compounds from the gas stream to a mixture comprising C02 / bromine, hydrogen bromide and H20. The catalyst and process of the present invention are particularly convenient for treating a stream of gas containing one or more elemental halogens, or containing one or more organic compounds comprising halogen, which form elemental halogens during the catalytic oxidation process. When halogen-containing organic compounds are oxidized on catalysts, elemental halogen, (HX) and hydrogen halide (X2) are formed. Elemental halogen has been found to have a poisonous effect on previously known catalysts, thereby reducing the activity of said catalysts. In order to overcome this problem, gas treatments were carried out under conditions to minimize the production of elemental halogen, or were carried out at relatively high temperatures to reduce the effect on the catalyst * When the halogen in the gas feed is chlorine or fluorine, in general it has been possible to reduce the amount of elemental halogen in the resulting gas to less than 3% by weight of the total halogen-containing compounds (X2 and HX) present by adjusting the amount of hydrogen available in the feed stream. This is generally done by adding enough water to provide hydrogen for reaction. However, when the halogen in the organic compound containing halogens is bromine, it has been found that the formation of Br2 can not be easily controlled by the injection of water. In this way, when the halogen is bromine, the resulting gas stream generally contains a significant portion of the bromine in elemental form. That is, well above 3% by weight and often over 80% by weight of bromine in the resulting gas is in the form of Br2 instead of HBr. Therefore, it has not been possible to overcome the problem of Br2 poisoning by adjusting the composition of the feed gas. As a result, these bromine-containing catalysis reactions have had to be conducted at elevated temperatures resulting in various problems, such as higher energy costs. It has been found that the catalysts of the present invention are resistant to this elemental halogen poisoning, and thus are particularly convenient to use when the halogen is bromine. The present catalysts are also particularly suitable for use with any halogen-containing gas stream wherein the product stream contains more than 3% by weight dj Ifu halogen in elemental form. In this way, streams of g ^ e containing chlorine can be reacted on the present * catalysts, without need for adding excess hydrogen or water to maintain the Cl2 level below 3%. This can result in negligible cost savings and ease of operation to treat these chlorine-containing gas streams. Another characteristic of the catalysts of the present invention is that they were found to remain stable at temperatures up to 550 ° C-600 * C, and even higher without deactivation. In this way, the regeneration of the catalysts present by thermal activation can be conducted at relatively higher temperatures, such as 500 ° C-550 ° C, thus allowing these regenerations to be performed faster and more efficiently than for some previously known catalysts. The problem of elemental halogen poisoning has been found to occur particularly in catalysts containing vanadium oxide. It is considered that the elemental halogen is reactive with vanadium oxide and thus can poison said catalysts. Therefore, in a preferred embodiment of the present invention, the catalyst is substantially free of vanadium. Although vanadium is not a desirable component of the present catalyst, it has to be understood that the presence of an incidental amount of f-p-nadium will not have a significant impact on the effectiveness of the catalyst. Therefore, although the catalyst is preferably free of any detectable level of vanadium, the catalyst should still be considered "substantially free of vanadium" as long as it contains less than 0.049% by weight of vanadium (as V205). As previously stated, this invention provides catalysts and methods for using said catalysts to treat gas streams containing compounds selected from the group consisting of halogenated organic compounds, non-halogenated organic compounds, carbon monoxide and mixtures thereof. Catalysts and processes are particularly suitable for treating gas streams which additionally contain one or more molecular halogens, or gas streams where these molecular halogens are formed during the catalytic treatment and more particularly to gas streams including bromine. The catalysts of this invention comprise one or more metals of the platinum group, zirconium oxide and at least one manganese oxide, cerium oxide, or cobalt oxide. The metals of the platinum group as used herein are platinum, palladium and rhodium. When reference is made here to one or more metal oxides or oxides of a metal, it is intended to include all the oxide forms of said metals and their mixtures as well as hydroxo-oxides, hydrous oxides and the like. Typically, the catalysts of this invention contain about 40 to about 88 wt.% Zirconium oxide (as Zr02) preferably about 60 to about 85 wt.%; and from about 3 to about 48% by weight of one or more manganese, cerium or cobalt oxides, preferably to about 10 to 30% by weight. Good results are obtained when the metal of the platinum group is present in the catalyst in an amount of about 0.01 to about 8% by weight of the catalyst and particularly an amount of at least about 0.1% by weight. In a preferred embodiment, the catalyst is characterized by a core material comprising zirconium oxide and one or more oxides of manganese, cerium or cobalt, with a component of the platinum group dispersed in this core material. The preferred platinum group metal is platinum. Typically, the core material of this invention contains up to about 90 wt.% Zirconium oxide (Zr02), preferably about 50 to about 80 wt.%. In the case of a core material comprising manganese oxide and zirconium oxide, it is desirable that the manganese be present in the core material in an amount of up to about 50% by weight (as Mn203); typically containing at least about 10% by weight of manganese oxide, and preferably about 15 to about 35% by weight.

In the case of a core material comprising cerium oxide and zirconium oxide, it is desirable that cerium oxide be present in the core material in an amount of up to about 50% by weight (as Ce02); typically it contains at least 14% by weight of cerium oxide and preferably from about 15 to about 25% by weight. In the case of a core material comprising cobalt oxide and zirconium oxide, it is desirable that cobalt oxide be present in the core material in an amount of up to about 50% by weight (as C0304); typically containing at least about 10% by weight and preferably about 15 to about 35% by weight. The core material can be combined with other materials such as binders or adhesion auxiliaries or active components such as titanium oxide and / or aluminum oxide. The core material can be prepared by means well known to those of ordinary skill in the art and includes physical blends, co-gelling, co-precipitation or impregnation. Preferred techniques for preparing the core material of this invention are co-gelling and co-precipitation. For additional details of these methods of U.S. Pat. No. 4,085,193 which is incorporated by reference for its teaching of techniques for co-precipitation and co-gelation. The impregnation can be employed in a manner analogous to the methods discussed with respect to dispersing platinum group metals and other components in the core material. For example, a core material of zirconium oxide and manganese oxide, can be prepared by mixing aqueous solutions of convenient zirconium oxide precursor such as zirconium oxynitrate, zirconium acetate, zirconium oxychloride or zirconium oxysulfate and an oxide precursor of suitable manganese, such as manganese nitrate, manganese acetate, manganese dichloride or manganese dibromide, add a sufficient amount of a base such as ammonium hydroxide to obtain a pH of 8-9, filter the resulting precipitate, wash with water, dry at 120 * C-150 * C and then calcined at 450 ° C-500 ° C. A similar process employing a cerium or soluble cobalt compound such as cerium nitrate, cerium acetate, cerium sulfate or cerium chloride, cobalt nitrate, cobalt chloride or cobalt bromide can be used if a material is desired. core comprising zirconium oxide and cerium or cobalt oxides. It is desirable that the core material and catalyst of this invention have a surface area of from about 25 n / g to about 250 Vg, preferably from about 50 to about 250 m2 / g. The platinum group metals can be dispersed on the core material by means well known in the art.

Impregnation is the preferred method. The impregnation can be carried out by techniques well known to those of ordinary skill in the art. The metal can be dispersed on the core material by impregnating the material with a solution containing a compound of the desired platinum group (s). The solution can be an aqueous or non-aqueous solution (organic solvent). Any metal of the platinum group may be present as long as the compound is soluble in the selected solvent and decomposes the metal when heated in air at elevated temperatures. Illustrative of these metal compounds of the platinum group are chloroplatinic acid, ammonium chloroplatinate, bromoplatinic acid, platinum hydrate tetrachloride, dichlorocarbonyl platinum dichloride, dinitrodia in platinum, amine-solubilized platinum hydroxide, rhodium trichloride, hexane inorodium chloride, carbonyl rhodium chloride, rhodium hydrate trichloride, rhodium nitrate, rhodium acetate, chloropalladic acid, palladium chloride, palladium nitrate, diamine hydroxide palladium and tetraamine palladium chloride. The impregnation of the particles or powder with the metal compound solution can be carried out in forms well known in the art. A convenient method is to place the core material in particle form, for example granules, on a rotary evaporator that is partially submerged in a heating bath. The impregnation solution containing a quantity of the desired metal compound to provide the desired concentration of oxide or metal in the finished catalyst is now added to the core material and the mixture is cold rolled (without heat) for a time of about 10 to 60. minutes Next, heat is applied and the solvent evaporates. This usually takes from about 1 to about 4 hours. Finally, the solid is removed from the rotary evaporator and calcined in air at a temperature of about 400 * C-600 ° C for about 1 to 3 hours. If more than one component is desired, they can be impregnated simultaneously or sequentially in any order. Alternately, the pulverulent core material is placed in a planetary mixer and the impregnation solution is added under continuous stirring until a state of incipient moisture is achieved. The powder is then dried in an oven for 4 to 8 hours and calcined at about 400 ° C-600 ° C for about 1 to 3 hours. Other methods of dispersing these oxides on the core material are co-precipitation and co-gelation. The catalyst of the present invention can be used in any configuration, shape or size that exposes it to the gas to be treated. For example, the catalyst can conveniently be used in particulate form or the catalyst can be deposited on a solid monolithic carrier. When the particle form is desired, the catalyst can be formed into structures such as tablets, nodules, granules, rings, spheres, etc. The particulate form is especially convenient when large volumes of catalysts are required and for use in circumstances in which frequent replacement of the catalyst may be desired. In circumstances where less mass is desired or where the movement or agitation of the catalyst particles can result in attrition, dust formation and resultant loss of dispersed metals or oxides or an undue increase in pressure flow through the particles Due to high gas flows, a monolithic shape is preferred. In the use of a monolithic form, it is usually more convenient to employ the catalyst as a thin film or coating deposited in an inert carrier material that provides the structural support for the catalyst. The inert carrier material can be any refractory material such as ceramic or metallic materials. It is convenient that the carrier material is not reactive with the catalytic components and is not degraded by the gas to which it is exposed. Examples of suitable ceramic materials include sillimanite, petalite, cordierite, mulita, zirconium, zirconium zirconium, eßpodumeno, aluminum oxide titanate, etc. Additionally, metal materials that are within the scope of this invention include metals and alloys as described in US Pat. No. 3,920,583 (incorporated herein by reference) which are resistant to oxidation and otherwise are capable of withstanding high temperatures. For the treatment of gases containing halocarbons, ceramic materials are preferred. The monolithic carrier material can best be employed in any rigid unit configuration that provides a plurality of pores or channels extending in the direction of gas flow. It is preferred that the configuration be a honeycomb configuration. The honeycomb structure can advantageously be used either in unitary form or in a multi-module assembly. The honeycomb structure is usually oriented in such a way that the gas flow in general is in the same direction as the cells or channels of the honeycomb structure. For a more detailed discussion of the monolithic structures, reference is made to the U.S. patent. No. 3,785,998 and the US patent. No.3, 767,453, which are incorporated here by reference. If a particulate form is desired, the catalyst can be formed into granules, spheres or extrudates by means well known in the industry. For example, the catalyst powder can be combined as a binder such as a clay and rolled in a disk pelletizing apparatus to give catalyst spheres. The amount of binder can vary considerably but for convenience it is present from about 10 to about 30% by weight.

If a monolithic form is desired, the catalyst of this invention can be deposited on the monolithic honeycomb carrier by conventional means. For example, sludge can be prepared by means known in the art such as by combining the appropriate amounts of the catalyst of this invention in powder form, with water. The resulting slurry is subjected to ball milling for approximately 8 to 18 hours to form a usable sludge. Other types of mills such as impact mills can be employed to reduce the milling time from about 1 to 4 hours. This slurry can now be used to deposit a thin film or coating of the catalyst of this invention on the monolithic carrier by means well known in the art. Optionally, an adhesion aid such as alumina, silica, zirconium silicate, aluminum silicate or zirconium acetate, may be added in the form of an aqueous slurry or solution. A common method involves immersing the monolithic carrier over the sludge, blowing off the excess sludge, drying and calcining in air at a temperature of about 450 ° C to about 600 ° C for about 1 to about 4 hours. The catalyst of this invention is present in the monolithic carrier in an amount in the range of 1 to 4 g of catalyst per 16.39 cm3. (1 in3) of carrier volume and preferably of about 1.5 to 3 g / 16.39 cm3 (1 in3) An alternate method of preparation is to disperse the metal component of the platinum group onto a monolith coated with core material in a form analogous to the previously described one, that is, the monolithic honeycomb carrier that has dispersed core material and other optional components, can be submerged in a An aqueous solution containing a noble metal compound soluble and susceptible to decomposition, dried and calcined at a temperature of 400 to 500 ° C for about 1 to about 5 hours. Any metal compound of the platinum group susceptible to decomposition as listed above, may be employed. The concentration of metals, of platinum group is also as stated above. Another embodiment of this invention relates to a process for destroying or converting, by oxidation and / or hydrolysis, halogenated organic compounds (also referred to herein as organohalogen compounds) and other organic compounds present in a gas stream comprising contacting the gas stream to a gas stream. temperature about 175 ° C to about 550 ° C and preferably at a temperature of about 250 ° C to about 475 ° C with the catalyst previously described. The organohalogen compounds which can be treated are any organic compounds containing at least one halogen atom in the structure of the compounds. Some specific examples are chlorobenzene, dichlorobenzene, fluorobenzene, carbon tetrachloride, chloroform, methyl chloride, vinyl chloride / methylene chloride, ethyl chloride, ethylene chloride, ethylidene chloride, 1,2-trichloroethane, 1,1 -trichloroethane methyl bromide, ethylene dibribomide, trichlorethylene, tetrachlorethylene, polychlorinated biphenyls, chlorotrifluoromethane, dichlorodifluoromethane, 1-chlorobutane, methyl bromide, dichlorofluoromethane, chloroform acid, trichloroacetic acid, and trifluoroacetic acid. The process of this invention can also treat a gas stream containing other organic compounds that do not contain any halogens in its structure. These other organic compounds include hydrocarbons, oxygenates, amines, etc. Specific examples include benzene, toluene, xylenes, phenol, ethyl alcohol, methyl acetate, methyl formeate, isopropylamine butyl phthalate aniline, formaldehyde, methyl ethyl ketone, acetone, etc .; Many gas streams already contain enough oxygen (02) to oxidize all contaminants and most gas streams contain a large excess. In general, a large excess of oxygen greatly facilitates the oxidation reaction. In the event that the gas stream does not contain sufficient oxygen, preferably oxygen as air, it can be injected into the gas stream before contact with the catalyst. The minimum amount of oxygen that must be present in the gas stream is the stoichiometric amount needed to convert the carbon and hydrogen of the compounds present in carbon dioxide and water. For convenience and to ensure that the oxidation reaction is complete, it is desirable that an excess of oxygen be present. Accordingly, it is preferable that at least twice the stoichiometric amount and more preferably at least 5 times the stoichiometric amount of oxygen be present in the waste gas stream. It is also understood that the process of the present invention does not depend on the concentration of organic compounds and / or organotrophic compounds. In this way, gas streams with a very wide range of concentration of contaminants can be treated by the present process. The process of this invention is also applicable to processes wherein liquid organohalogen compounds and organic compounds are evaporated and mixed with oxygen. The invention has been found to be particularly useful for treating ventilation gases derived from industrial processes that produce phthalic acid compounds such as terephthalic acid (TPA), purified terephthalic acid, isophthalic acid (IPA) and alizarinic acid from xylene by catalytic reactions that use bromine as initiator. Similarly, trimellitic anhydride is prepared by catalytic processes from trimethylbenzene using bromine as the initiator. In addition, catalyzed reactions that reproduce dicarboxylic acids from dimethyl naphthalene also use bromine. The desired acid end product of these reactions is typically recovered by condensation, leaving a waste gas stream of ventilation, consisting of various volatile organic compounds such as toluene, xylene, benzene, methyl for ate, acetic acid, alcohol, carbon and methyl bromide. Compared to conventional catalytic control, the processes and catalysts of this invention provide the advantage of effective catalytic oxidation of the vent gas constituents at reduced operating temperatures and / or catalyst volume. Another application of the invention involves the treatment of volatile organic compounds and halogenated organic compounds, particularly chlorinated organic compounds such as chloroform and dioxin, derivatives of pulp chlorine leaching. The requirement of the volume of said catalyst for a given application is usually referred to as the volume hourly space velocity (VHSV) which is defined as the ratio of gaseous flow rate per hour to the volume of the catalyst bed. In the practice of this invention, the volume hourly space velocity (VHSV) may vary substantially, preferably from about 1,000 to about 100,000 h "1 and more preferably from 5,000 to about 50,000 h" 1 based on the calculated gas velocities at standard pressure temperature For a fixed flow rate, the VHSV can be controlled by adjusting the size of the catalyst bed Once the gas stream has been contacted with the catalyst and the contaminants have been destroyed, the gas stream The catalyst treated can be further treated, if desired, to remove the halogen acid and any halogens that are formed during the conversion process.For example, the treated gas stream can be passed through a depuration: to absorb the acid. The scrubber may contain a base such as sodium or ammonium hydroxide which neutralizes the acids and solubilizes the halogens with hypohalites and halides This invention is exemplified in the following examples. Of course, these examples are not intended to limit the invention since modifications to the examples by ordinary resources will be readily apparent to those of ordinary skill in the art. Example X Tests were performed to demonstrate the high stability and activity of the catalysts of this invention. A catalyst C was prepared which comprises a honeycomb carrier based on monolithic cordierite coated with manganese oxide and zirconium oxide in which platinum is dispersed. The catalyst is aged in a test gas stream containing 50-100 ppm of methyl bromide at 10,000 h "1 VHSV at 45 ° C for 200 hours.

After this aging, the catalyst still destroys more than 99% of the methyl bromide in a test stream containing 50-100 ppm of methyl bromide at 20,000 h "1 VHSV at 350 * 0. A 2 A mixture of 20 % solution of zirconium oxynitrate (790 g) and 50% manganese nitrate solution (100 g) is prepared.A 7 M solution of ammonium hydroxide is added to this mixture with constant stirring to obtain a pH of 3.5 and gel formation.A liter of water is added to the gel and the gel is broken by stirring with a large spatula.A 7M ammonium hydroxide solution is added to obtain pH 8-9.This mixture is then filtered and washed with additional water The resulting powder is dried at 120 ° C overnight and then calcined at 500 ° C for two hours to yield a co-precipitated zirconium oxide / manganese oxide powder.

The zirconium oxide / manganese oxide catalyst prepared in Example 2 is impregnated with 80 g of platinum hydroxide solubilized with aqueous amine (H2Pt (0H) ß) in solution (15.1% Pt) and 69.7 g of water. The powder is then dried at 120 ° C overnight and calcined at 500 ° C for one hour, a cordierite honeycomb of 7.62 cm (3") in length and 400 cells by 6.45 cm: (1" 2) is coated by After submerging, the excess mud is blown off with an air gun, the sample is dried at 120 ° C for one hour, and calcined at 500 ° C for one hour, this procedure is repeated until the monolith has a loading of 1.5 g / 16.39 cm3 (1 in3) of catalyst Example 4 A platinum powder in cerium oxide / zirconia is prepared in the same manner as the platinum catalyst in manganese oxide / zirconium oxide described in Example 3, using 800 g of cerium oxide / zirconium oxide (20% Ce02) and impregnated with 80 g of platinum hydroxide solubilized with aqueous amine (HaPt (0H) 6) in solution (15.1% Pt) and 69.7 g of water The powder of this example is applied to the honeycomb without the alumina adhesion aid Example 5 A mixture a 20% solution of oxy Zirconium treatment (790 g) and a 50% solution of manganese nitrate (100 g) and 81.32 g of cobalt nitrate is prepared. A 7 M solution of ammonium hydroxide is added to this mixture with constant stirring to obtain a pH of 3.5 and gel formation. One liter of water is added to the gel and the gel is broken by shaking with a spatula. A solution of 7 M ammonium hydroxide is added to obtain pH 8-9. This mixture is then filtered and washed with additional water. The resulting powder is dried at 120 ° C overnight and then calcined at 500 ° C for two hours to give the zirconium oxide / manganese oxide / cobalt oxide azole. This powder is then impregnated with platinum in the same manner as described in Example 3.

A test generally used to evaluate the efficiency of the catalyst for destruction of halogenated organic compounds and other organic compounds uses a quartz tube reactor with a diameter of 2.54 cm (1") placed inside a Lindberg furnace. top of the tube and circulate downward over the catalyst.The catalyst in a honeycomb monolith having a diameter of 2.22 cm (7/8") and a length of 2.54 cm (1") is placed in the middle of the tube and the destruction of organic compounds by the catalyst is evaluated.The catalyst is tested at temperatures in the range of 175 ° C to 450 ° C. The ali enteition gas containing 50 ppm of methyl bromide, 10 ppm of toluene and 10 ppm of benzene, 7000 ppm CO, 3% 02 and 2.5% of H20. After aging at 450 ° C in this stream for 176 hours, the conversions of these organic species and CO were measured at 30,000 h.x. A hydrocarbon analyzer (FID) and a gas chromatograph were used to analyze the compositions in the Inlet and outlet gas samples Conversion efficiency is calculated at various temperatures using equation 1:% conversion [(Cln - Cout.) / Cln] x 100 (1) where Cln is the concentration at the input of the organic compound to be converted, and Cout is the concentration at the exit The results of the above tests are illustrated in the following table to exemplify the high destruction efficiencies for halogenated organic compounds and other organic compounds using the catalysts of this invention. l Temperature fifjtcjep? ja. <; fle Peefrruooióp (%) (ttC) CO Tolueno bncno Bromro Mefr or 250 50 40 20 28 300 90 85 30 78 350 99+ 99+ 95+ 99+ 400 99+ 99+ 99+ 99+

Claims (35)

1. REXVTHDI ACIONIBS 1.- Catalyst for treating a gas stream containing compounds selected from the group consisting of halogenated organic compounds, non-halogenated organic compounds, carbon monoxide and mixtures thereof, the catalyst is characterized in that it comprises at least one compound of the platinum group , zirconium oxide and manganese oxide, in an amount of at least about 10% by weight (such as Mn203), and wherein the catalyst is substantially free of vanadium.
2. 2. The catalyst in accordance with the claim 1, wherein the gas stream comprises a halogenated organic compound.
3. 3. The catalyst in accordance with the claim 2, wherein the gas stream comprises a brominated organic compound.
4. 4. The catalyst according to claim 1, wherein the gas stream further comprises at least one elemental halogen.
5. 5. The catalyst according to claim 4, wherein the elemental halogen is present in the gas stream in an amount of at least about 3% by weight of the total amount of the halogen-containing compounds present.
6. 6. The catalyst according to claim 4, wherein the elemental halogen is Br2.
7. 7. - The catalyst according to claim 1, wherein the catalyst is a core material comprising zirconium oxide and manganese oxide.
8. 8. The catalyst according to claim 7, wherein the zirconium oxide is present from core material in an amount of about 50% by weight to about 90% by weight (as ZrOa).
9. 9. The catalyst according to claim 7, wherein the manganese oxide is present in the core material in an amount of about 10% by weight to about 50% by weight (such as Mn203).
10. 10. The catalyst according to claim 7, wherein the core material consists essentially of zirconium oxide and manganese oxide.
11. 11. The catalyst according to claim 1, wherein the metal of the platinum group is present in an amount from about 0.1% to about 8% by weight of the catalyst.
12. 12. The catalyst according to claim 11, wherein the metal of the platinum group is present in an amount of at least about 0.5% by weight of the catalyst.
13. 13. The catalyst according to claim 7, wherein the surface area of core material is from about 25 m2 / g to about 275 m2 / g.
14. 14. - A catalyst for treating a gas stream containing compounds selected from the group consisting of halogenated organic compounds, non-halogenated organic compounds, carbon monoxide and mixtures thereof, the catalyst comprising: (i) a core material consisting essentially of zirconium oxide and manganese oxide in an amount of at least about 10% by weight (as Mn203); and (ii) at least one metal of the platinum group dispersed in the core material in an amount of from about 0.1% to about 8% by weight, based on the total weight of the catalyst, wherein the catalyst is substantially free of vanadium.
15. 15. A process for treating a gas stream containing compounds selected from the group consisting of halogenated organic compounds, non-halogenated organic compounds, carbon monoxide and mixtures thereof, the method comprising contacting the gas stream at a temperature of about 175. "C up to about 550'c with a catalyst comprising at least one metal of the platinum group, zirconium oxide and manganese oxide in an amount of at least about 10% by weight (such as Mn203) and wherein the catalyst is substantially free Vanadium
16. 16. The process according to claim 15, wherein the gas stream comprises a halogenated organic compound.
17. 17. The process according to claim 16, wherein the gas stream comprises a brominated organic compound.
18. 18. The method according to claim 15, wherein the gas stream further comprises at least one elemental halogen.
19. 19. The process according to claim 18, wherein the elemental halogen is present in the gas stream in an amount of at least about 3% by weight of the total amount of the halogen-containing compounds present.
20. 20. The process according to claim 18, wherein the elemental halogen is Br2.
21. 21. The process according to claim 15, wherein the catalyst is characterized by core material comprising zirconium oxide and manganese oxide.
22. 22. The process according to claim 21, wherein the zirconium oxide is present in the core material in an amount of about 50% by weight to about 90% by weight (as Zr02).
23. 23. The process according to claim 21, wherein the amount of manganese oxide present in the core material in an amount of about 10% by weight to about 50% by weight (such as Mn203).
24. 24. - The process according to claim 21, wherein the metal of the platinum group is dispersed in the core material.
25. 25. The process according to claim 21, wherein the metal of the platinum group is present in an amount from about 0.1% to about 8% by weight of the catalyst.
26. 26. The process according to claim 11, wherein the metal of the platinum group is present in an amount of at least about 0.5% by weight of the catalyst.
27. 27. The process according to claim 21, wherein the surface area of core material is from about 25 μg to about 275 m2 / g.
28. 28.- A method for treating a gas stream containing compounds selected from the group consisting of halogenated organic compounds, non-halogenated organic compounds, carbon monoxide and mixtures thereof, the method comprising contacting the gas stream at a temperature of about 175"C up to about 550 ° C, with a catalyst comprising (i) a core material consisting essentially of zirconium oxide and manganese oxide in an amount of at least about 10% by weight, and (ii) at least one metal from the dispersed platinum group in the core Raterial in an amount from about 0.1% to about 8% by weight of the catalyst, wherein the catalyst is substantially free of vanadium
29. 29. The process according to claim 28, wherein the metal of the platinum group is platinum
30. 30.- A process for treating a gas stream containing at least one brominated organic compound , the method comprises contacting the gas stream with a catalyst comprising at least one metal of the platinum group, zirconium oxide and manganese oxide, and wherein the catalyst is substantially free of vanadium.
31. 31. The process according to claim 30, wherein the gas stream further comprises non-brominated organic compounds, carbon monoxide or mixtures thereof.
32. 32. The method according to claim 1, wherein it further comprises cerium oxide.
33. 33. The method according to claim 1, wherein it also comprises cobalt oxide.
34. 34.- The method according to claim 7, wherein the core material is prepared by a co-gelling or co-precipitation process.
35. 35. - The method according to claim 14, wherein the core material is prepared by a co-gelling or co-precipitating process. A catalyst and a process for treating gas streams containing halogenated organic compounds, non-halogenated organic compounds, carbon monoxide or mixtures thereof and particularly organobromide-containing gas streams. The catalyst comprises at least one metal of the platinum group, zirconium oxide and at least one cerium or cobalt manganese oxide. RS / frp / 19 / PCTOSO 35