III International Conference

PP-III-65In spite of the fact that the hydrocarbon reforming reactions proceed quickly andequilibrate rapidly, both radial and axial temperature gradients may arise in monolith reactors.The metallic monolith catalysts employed in the experiments secured an extremely efficientdissipation of the reaction heat trough a proper choice of support material and monolithgeometry. Nevertheless, in the range of the experimental parameters applied, the longitudinaltemperature gradients of about 100 degrees for the partial oxidation reforming and of60-80 degrees for the gasoline-air-steam (autothermal reforming) feed mixture wereexperimentally detected in the metallic monoliths. The temperature profiles are results ofinterplay among kinetics, hydrodynamics, and heat transfer.Fundamental understanding of the processes occurring in the multiscale levels, theirinterrelation and interaction is essential to control such intensive, fast reaction in a specificmonolith reactor. Information about dynamics of the local temperature and concentrationsmay have a considerable influence on rational design of both reactor and catalyst as well asthe choice of design materials. A dynamic mathematical model with detailed molecular,unsteady-state kinetics for surface reactions was used to simulate the methane partialoxidation process in the monolith reactor.Also discussed are problems encountered with a short contact time reactor operating at apilot scale, issues that are largely independent of the catalysts employed. Radiant heat transferaffects the behaviour of the monolith reactor due to transmission of heat against the directionof the feed stream, which otherwise takes place principally by the solid thermal conduction inthe wall of reactor and monolith. Moreover, it was found that this particular reactor design isprone to pre-reformation of the fuel prior to catalytic reaction and breakthrough of the feedmixture in the monolith reactor. Feed composition, superficial velocity, and design factorsaffect these phenomena in monolith reactors [5].Acknowledgement. This work is in part supported by RFBR 060381037 Project.References1. L. D. Schmidt, E. J. Klein, C. A. Leclerc, J. J. Krummenacher and K. N. West, Syngas inmillisecond reactors: higher alkanes and fast lightoff, Chemical Engineering Science, Volume 58,Issues 3-6, (2003) 1037-1041.2. M.Pacheco, J. Sira and J. Kopasz , Reaction kinetics and reactor modeling for fuel processing ofliquid hydrocarbons to produce hydrogen: isooctane reforming, Appl. Catalysis A: General,Volume 250, Issue 1, (2003) 161-175.3. V.A. Sadykov et.al., Selective Oxidation of Hydrocarbons into Synthesis gas at Short ContactTimes: Design of Monolith Catalysts and Main Process Parameters. Kinetics and Catalysis, 46(2005), 227–250.4. L. Bobrova,I. Zolotarskii, V. Sadykov, S. Pavlova, O. Snegurenko, S. Tikhov, V. Korotkich, T.Kuznetsova, V. Sobyanin, V. Parmon, Syngas Formation by Selective Catalytic Oxidation of LiquidHydrocarbons in a Short Contact Time Adiabatic Reactor. Chem. Eng. Journal, 107 (2005) 171-179.5. L. Bobrova, I. Zolotarsky, V. Sadykov, V. Sobyanin, Hydrogen-Rich Gas Production fromGasoline in a Short Contact Time Catalytic Reactor, Int. J. of Hydrogen Energy (2006) in press.590