OP-II-3

OP-II-17Catalytic reactions were carried out in specially designed reactors, and thecatalytic properties were compared with those of powders (7%VO x /TiO 2 ) or of coatedbeads (Pt/Al 2 O 3 ). In the latter case for example the hot spot temperature and MCHconversion were studied for three foams differing by the material (FeCrAlloy or α-alumina), ppi and porosity, and compared to coated beads (Table 1). Ca. 2.6 g ofPt/Al 2 O 3 was coating foam insert or beads displayed in a 19 cm-long house-designedreactor. In all cases the hot spot was higher for beads while the conversion trend isless easy to see. Therefore even for highly exothermic reactions not limited byexternal transport, coated foams significantly increase the effective conductivity ofcatalytic beds, the higher foam density leading to a higher effective conductivity.Figure 1. Electron Probe Micro Analysis of a branch of stainless steel foam (left) and plate(right) coated by TiO 2 /SiO 2 after RPECVD, and profiles of Fe, Ti, Si (middle) along the whitearrow (right).Table 1. Hot spot (ΔT) and MCH conversion (X) for three foams and for zeolithic beads.W/F MCH (kg cata .s.mol –1 )F1 : Metallic 33ppi*, ε # = 97%F2 : Metallic 33ppi, ε = 81%F3 : Ceramic 37ppi, ε = 87%Molecular sievesBead ∅ 2 mmΔT°C X (%) ΔT°C X (%) ΔT°C X (%) ΔT°C X (%)15.3 36 97 8 95 12 77 35 9630.6 40 88 11 87 19 74 49 91* ppi: pound per square inch; # ε: porosity; Q H2 = 3.3·10 –4 mol.s –1 ; T°controller 300°C.References[1]. T. Giornelli, A. Lofberg, E. Bordes-Richard, Appl. Catal. A : General, 2006, 305, 197-203.[2]. M. Roumanie, V. Meille, C. Pijolat, G. Tournier, C. de Bellefon, P. Pouteau, C. Delattre, Catal.Today 2005, 110, 164-170.[3]. V. Meille, Appl. Catal. A: General 2006, 315, 1-17.[4]. T. Giornelli, A. Lofberg, L. Guillou, S. Paul, V. Le Courtois, E. Bordes-Richard, Catal. Today,2007, 128, 201-207.[5]. A. Essakhi et al.A. Lofberg, P. Supiot, B. Mutel, S. Paul, V. Le Courtois, E. Bordes-Richard, Proc.6th Int. Symp. Polyimides and Other High Temperature/High Performance Polymers, Melbourne,Florida, USA, November 9-11, 2009. Accepted.AcknowledgementsThe Agence nationale pour la Recherche is acknowleged for A. Essakhi’s grant andfinancial support.131