III International Conference

PP-III-86PARTIAL OXIDATION OF METHANE IN MONOLITH REACTOR: EFFECTS OFTHE INTERNAL CONFIGURATION AND MATERIALSVernikovskaya N.V. 1, 2 , Bobrova L.N. 1, 2 , Sadykov V.A. 1, 2 , SobyaninV.A. 11 Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia2 Novosibirsk State University, Novosibirsk, RussiaE-mail: vernik@catalysis.nsk.suThe work concerns mathematical modeling of methane partial oxidation dynamics,especially during the reaction ignition in monolith reactor. Dissipation of reaction energyinternally through the different mechanisms, such as radiation, convection, conduction andthermodiffusion is considered in dependence on configuration and material of both monolithscatalystand heat shield. In addition to the detail surface kinetics the gas phase reactions aretaken into account in the mathematical model developed.Partial oxidation of hydrocarbons to synthesis gas in monolith reactor at short contacttimes is characterized by the high temperature in the frontal part of catalyst [1-2]. To avoidthe heat losses by radiation a heat shield are usually placed before the catalytic monolith. Thetemperature between the heat shied(s) placed upstream of the catalyst and catalyst maygradually go up with the run time. The high temperature initiates pre-reforming reactionsupstream of the catalyst with releasing of some chemical energy in the noncatalytic reactions.This phenomenon may be favored in syngas production because of a milder catalysttemperature profile is created. Furthermore, hydrogen formed in the catalytic partial oxidationreaction may pass into the gas phase upstream the flow due to thermodiffusion. Thus, the twophase1D numerical model of methane partial oxidation takes into account a specificconfiguration of the monolith reactor with the heat shield and catalytic monoliths inside.The reactor model is developed on the base of differential equations of mass and energychanges [3]. The detail surface and gas phase reactions are taken into account in themathematical model developed. Accumulation terms are considered in all equations. Thefollowing assumptions are considered in the model: isolation of sidewalls of the monolithreactor; non steady-state heat– and mass transfer; heterogeneously of the system; both theaxial and thermo diffusions in the gas phase; thermal conduction of solid phase by means ofeffective axial thermal conductivity; heat loss due to radiation at the reactor inlet and outlet.Dissipation of reaction energy in the reactor internally is considered in dependence onboth geometry and material of the monoliths.632