The effects of radiation and particle size on the pyrolysis of biomass particles

Abstract

This article presents the structure of laminar, one-dimensional, and steady-state flame propagation in uniformly premixed wood particles. In order to predict the effect of radiation and particle size on the pyrolysis of biomass particles, the flame structure is divided into three regions: a preheat vaporization zone where the rate of the gas-phase chemical reaction is small; a narrow reaction zone composed of three zones (gas, tar, and char combustion) where convection and the rate of vaporization of the fuel particles are small; and finally a convection zone where diffusive terms in the conservation equation are small. In this model, it is assumed that fuel particles vaporize first to yield a gaseous fuel of known chemical structure. The analysis is performed in the asymptotic limit, where the value of the characteristic Zeldovich number is large and the equivalence ratio is larger than unity (i.e. ϕu≥1). The overall investigation of this study leads to a novel non-linear burning velocity correlation. Consequently, the impacts of radiation and particle size as determining factors on the combustion properties of biomass particles are declared in this research.