Catalytic Combustion of Biogas-Hydrogen Mixtures in a Packed Bed Reactor

Catalytic combustion of lean premixed mixtures of biogas/air and biogas/hydrogen/airon Pt in a packed bed reactor has been investigated using detailed surface chemistry.Non-equilibrium, adiabatic and one dimensional flow assumptions have been adopted for simulation of the reactor. The interaction between two phases of porous medium is incorporated into the model via heat and mass transfer factors. Radiation heat transfer has been taken into account using effective thermal conductivity. All thermo-physical properties of the gas phase are considered to be temperature and concentration dependent. Two energy equations for two phases of the porous medium along with species transport equations are solved in the model. A mechanism of multi-step surfacere actions, suitable for oxidation of lean mixture of methane/air, has been adopted from literature and employed for simulations. This mechanism includes 36 single stepreactions with 11 surface and 6 gas phase species. Simulations have been conducted for oxidation of different biogas/air mixtures for the inlet temperature range of 700K to900K at atmospheric pressure. The effect of the addition of hydrogen to the biogas/airmixtures has also been investigated. It is shown that hydrogen improves oxidation of methane.