Preparation method of aluminum oxide film-layer carrier of integrated methane combustion catalyst

Abstract

The invention discloses a preparation method of an aluminum oxide film-layer carrier of an integrated methane combustion catalyst. The preparation method comprises the following steps: soaking a honeycomb-shaped carrier into aluminum sol; taking out the honeycomb-shaped carrier and removing the surplus aluminum sol on the surface; drying and roasting at the temperature of 800 DEG C to 1200 DEG C to form an aluminum oxide film layer which at least has any one crystal phase of beta-phase, theta-phase and alpha-crystal phase on the honeycomb-shaped carrier. The integrated methane combustion catalyst is prepared from the aluminum oxide film-layer carrier and an active component. The integrated methane combustion catalyst prepared by the invention has a high catalytic performance and a long service life.

Description

technical field [0001] The invention relates to the field of methane combustion catalysts, in particular to a method for preparing an alumina film layer carrier of an integral methane combustion catalyst. Background technique [0002] With the complexity of industrial applications and the characteristics of low-concentration and large-volume methane emissions in industry, the requirements for methane combustion catalysts are also getting higher and higher. However, at present, there are many preparation methods for monolithic methane combustion catalysts, which are mainly divided into the following four types: (1) monolithic molding technology, that is, the perovskite-type active component is mixed with a binder, and the honeycomb structure is formed by extrusion. Perovskite itself is not a clay material, and its strength is low when it is combined with a binder, and it is easily broken, resulting in a large consumption of catalyst; (2) the solution impregnation method of th...

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Problems solved by technology

However, at present, there are many preparation methods for monolithic methane combustion catalysts, which are mainly divided into the following four types: (1) monolithic molding technology, that is, the perovskite-type active component is mixed with a binder, and the honeycomb structure is formed by extrusion. Perovskite itself is not a clay material, and its strength is low when it is combined with a binder, and it is easily broken, resulting in a large consumption of catalyst; (2) the solution impregnation method of the honeycomb carrier, in the patent CN1058357, "Perovskite-type rare earth composite oxidation Combustion Catalysts” discloses that the cordierite-based honeycomb carrier is selected, and the cordierite-based honeycomb carrier is directly impregnated into the nitrate solution of metal ions, but because of the active metal ions adsorbed on the surface, the metal ions of the carrier itself will It is easy to react with active metal ions to form spinel-type stabilizers, resulting in a decrease in the content of perovskite active components, thereby reducing or inactivating its activity; (3) physical smearing method, first synthesize perovskite powder, and then It is blended with a binder, prepared into a slurry, and coated on the surface of the cordierite honeycomb carrier several times. This coating method belongs to the physical coating method. The catalyst prepared by this method maintains the perovskite crystal phase and Catalytic activity, but the active components are easy to fall off in the actual reaction process; (4) Modification of honeycomb carrier, patent CN101439290A, a kind of honeycomb ceramic type perovskite catalytic combustion agent, which discloses that a large amount of modification has been done on the surface of honeycomb carrier study, which mentions γ-Al 2 o 3 Coating of suspensions, but its application conditions are relatively mild (less than 500 ° C), therefore, for actual application conditions, it may break through the high temperature conditions above 800 ° C, and in long-term operation, γ-Al 2 o 3 Will be unstable, it tends to interact with active components, thereby reducing catalytic reactivity

Patent document CN105797766A "Integral Catalyst for Catalytic Combustion of Methane and Its Preparation Method" discloses the use of honeycomb ceramics as a carrier, rare earth composite alumina loaded with Pd and rare earth composite molecular sieve loaded with Pt, mixed to form a coating liquid, solidified On the carrier, it can be used for the combustion of low-concentration methane gas, but because noble metals such as Pa and Pt are easy to agglomerate, and the alumina it uses is γ-Al 2 o 3 , unstable in high temperature environment, easy to react with active components and reduce the performance of the catalyst

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