Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-III-5WASHCOATS FOR STRUCTURED REACTORS IN PROPANEOXIDATION. V 2 O 5 SUPPORTED ON TiO 2 WASHCOAT DEPOSITEDON METALLIC PLATES AND FOAMSA. Essakhi 1 , A. Löfberg 1 , S. Paul 1 , P. Supiot 2 , B. Mutel 2 , V. Le Courtois 1 ,E. Bordes-Richard 11Unité de Catalyse et de Chimie du Solide, UMR 8181, Université des Sciences etTechnologies de Lille, Bât. C3, Cité Scientifique, 59655 Villeneuve d'Ascq, France.Fax:+33-320436561; e-mail: axel.lofberg@univ-lille1.fr2Laboratoire de Génie des Procédés d’Interactions Fluides Réactifs-Matériau, Université desSciences et Techologies de Lille, Bât. C5, Cité Scientifique, 59655 Villeneuve d'Ascq, France.IntroductionMicroreactors or structured reactors (including heat exchanger-type reactors) offer apotential to conduct mass or heat transfer-demanding reactions under safe conditions whilemaintaining and/or increasing selectivity and productivity. In the case of reactions of selectiveoxidation of hydrocarbons the whole mass of the transition metal oxide is reacting in usualreactors (fixed or fluidized beds) and it is not so straightforward to get high catalyticactivity/selectivity in a thin layer. The goal is therefore to obtain high surface area whencovering a low, geometric area of the metallic substrate, while maintaining a high mechanicaland chemical stability [1,2]. The coating of aluminum and of stainless steel plates byVO x /TiO 2 catalysts for oxidative dehydrogenation of propane [2-4] was studied using dipcoatingand sol-gel methods, which provided high mechanical stability but poor chemicalstability as revealed by the iron poisoning of the catalyst. Another way of coating using aplasma-assisted chemical vapor deposition (PACVD) had already been explored in the case ofsilica supported cobalt for Fischer-Tropsch synthesis of clean fuels [4-6]. In the present paperthe parameters to control PACVD during the coating of metallic plates by VO x /TiO 2 catalystsfor ODH of propane are studied. The same PACVD technique was applied to metallic foamsfor the first time.Results and DiscussionPACVD of tetramethyldisiloxane used for silicon [6,7] was adapted to coat metallicsubstrates (here called S). A typical rate of increasing thickness of films of polymers is300 nm·mn –1 . A new sample holder was designed to allow the coating of metallic foam (Cr-Ni from Metafoam). After mineralisation in O 2 -N 2 plasma, a calcination step was applied tostabilize the layer of silica primer onto S. Titania was further deposited on the SiO 2 /S plate orfoam by using an alcoholic/aqueous suspension of titania (anatase) powder (Aldrich).311