OP-II-3

PP-I-35because it is difficult to oxidize by catalytic combustion (higher temperature and moreactive catalyst are required), so a good performance of the reactor can be easilyextended to other compounds. The foam support consists in a reticulated structure ofβ-SiC, which generates a network of open interconnected cells and provides highexternal surface area with low pressure drops [5, 6]. The Pd active phase has beenadded by incipient wetness impregnation to the non-washcoated foam support, sinceit has appreciable porosity (25 m 2 /g of BET surface area).The reactor, a 0.8 m length 0.05 m internal diameter 316 stainless steel tube,houses three different beds: a catalytic one in the middle (0.250 m length), and twoinert-ones (foam without active phase) at both sides (0.125 m length each). Theexperiments have been carried out under adiabatic conditions, as common inindustrial-scale RFRs of large diameter, using a special oven equipped with adynamic temperature control system. This unit, described in detail in previous works[7, 8], has been satisfactory tested, showing near-adiabatic operation. The mostimportant RFR operating conditions have been studied: surface velocity, feedhydrocarbon concentration and switching time. The results have been compared toexperimental data obtained in the same reactor for particulate and monolithic bedtypes. The comparison among the bed types must be done considering thedifferences in reactor stability, which are translated in higher or lower reactor lengths,catalyst cost and pressure drop.References[1] Matros, Y. S.; Bunimovich, G. A., Reverse-Flow Operation in Fixed Bed Catalytic Reactors.Catalysis Reviews 1996, 38, (1), 1 - 68.[2] Kolios, G.; Frauhammer, J.; Eigenberger, G., Autothermal fixed-bed reactor concepts. ChemicalEngineering Science 2000, 55, (24), 5945-5967.[3] Cybulski, A.; Moulijn, J. A., Structured Catalysts and Reactors. 2nd ed.; Taylor & Francis Group:2006.[4] Marin, P.; Hevia, M. A. G.; Ordonez, S.; Diez, F. V., Combustion of methane lean mixtures inreverse flow reactors: Comparison between packed and structured catalyst beds. Catalysis Today2005, 105, (3-4), 701-708.[5] Lacroix, M.; Nguyen, P.; Schweich, D.; Pham Huu, C.; Savin-Poncet, S.; Edouard, D., Pressuredrop measurements and modeling on SiC foams. Chemical Engineering Science 2007, 62, (12),3259-3267.[6] Twigg, M. V.; Richardson, J. T., Theory and Applications of Ceramic Foam Catalysts. ChemicalEngineering Research and Design 2002, 80, (2), 183-189.[7] Fissore, D.; Barresi, A. A.; Baldi, G.; Hevia, M. A. G.; Ordóñez, S.; Díez, F. V., Design and testingof small-scale unsteady-state afterburners and reactors. Aiche Journal 2005, 51, (6), 1654-1664.[8] Marin, P.; Ordonez, S.; Diez, F. V., Combustion of toluene-hexane binary mixtures in a reverse flowcatalytic reactor. Chemical Engineering Science 2008, 63, (20), 5003-5009.284