Numerical investigation of the effects of some selected thermo-physical properties on products evolution and yields during biomass pyrolysis

Abstract

ABSTRACTEffects of some selected biomass thermo-physical properties (biomass density, biomass thermal conductivity and char thermal conductivity) on the evolution and yields of pyrolysis products have been investigated. Wood cylinders were modelled as porous solids. Transport, solid mass conservation, intra-particle pressure generation and energy conservation equations were coupled and simultaneously solved to simulate the pyrolysis process. The first-order implicit Euler method was used to solve solid mass conservation equations. The transport, energy conservation and intra-particle pressure generation equations were discretized by the finite volume method. The generated set of linear equations was solved using the tri-diagonal matrix algorithm. Effects of selected thermo-physical properties were investigated on weight loss history, products evolution, intra-particle temperature gradient and tar secondary reactions. Total yields of tar and gas were then estimated. Results show that the selected thermo-physical properties influence weight loss history, product evolution, tar intra-particle secondary reactions and total product yields. The study also revealed that biomass density has the highest effect on product evolution and yields during pyrolysis.