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PP-I-35REVERSE FLOW REACTOR WITH FOAM CATALYSTS:EXPERIMENTAL STUDY AND PERFORMANCE COMPARISONMarín P., Ordóñez S., Díez F.Department of Chemical and Environmental Engineering. University of Oviedo.Julián Clavería 8. E-33006 Oviedo. SPAIN, marinpablo@uniovi.esReverse flow reactors (RFRs) belong to the group of fixed-bed reactors operatedunder forced unsteady-state conditions, in this case achieved by periodicallyreversing the feed flow direction. One of the most studied applications of this reactortype is the catalytic combustion of gaseous lean emissions of hydrocarbons. Themain advantage of using RFR technology is the high thermal efficiency, allowingautothermal operation with low temperature feeding and without auxiliary fuel, evenfor very lean hydrocarbon emissions (20-30°C of adiabatic temperature rise) [1, 2].Initially, the reactor bed must be pre-heated above the ignition temperature of thehydrocarbon-air mixture. Then, the pre-heating is discontinued, the feed is introducedat room temperature, and the periodic switching of the flow direction started. TheRFR principle is based on the difference of speed between a flowing gas and atemperature moving front travelling through the solid bed. Using an appropriatereversing switching time, part of the heat released by the exothermic reaction can betrapped inside the reactor in a half-cycle, being used to heat up the cold feed duringthe following half-cycle.Traditionally, RFRs have been filled with particulate catalysts (spheres,extrudates, Raschig rings, etc) [1]. However, particulate beds present an importantdisadvantage when treating high flow rate gaseous emissions, i.e. the high pressuredrop across the bed. For this reason, structured beds with low pressure drops, suchas monoliths or foams, have been successfully used for other environmental catalyticapplications (i.e. selective catalytic reduction of nitrogen oxides or automotivecatalyst, among others) [3]. The main problem for extending these bed types to theRFR technology is the lower thermal inertia of the catalytic bed in comparison toparticulate beds, resulting in a decrease of the reactor stability [4].In the present work, the performance of a foam catalytic bed is studiedexperimentally in a bench-scale RFR for the combustion of lean methane-airmixtures. Foam supports balance of the advantages and disadvantages of particulateand monolithic bed types. Methane has been selected as model hydrocarbon,283