Three zone kinetic model for characteristic analysis of heat loss parameters in a downdraft gasifier

Abstract

The article is focused on demostrating the combined effects of reaction and insulation parameters on syngas compostion during gasification process. A kinetic model is developed and implemented using FORTRAN program to simulate a downdraft gasifier using rubber wood as feedstock. The gasifier model consists of three zones: the pyrolysis, oxidation zone, and reduction zone; the gas composition and temperature distribution are estimated for each zone taking into account equilibrium ratios and reaction kinetics. To study the effect of heat loss, a novel expression in terms of insulation parameters is included for each zone. The properties of biomass composition and oxidant along with reaction constants is supplied as input parameter to the model.The results obtained from the model have been validated with experimental values. The effect of air supply and moisture content, coupled with properties of thermal insulation on final syngas composition and temperture is discussed. The analysis is useful for understanding the effects of energy interaction and it's losses, chemical reactions and operating conditions to maximize the energy output of the gasification process.