Finite element modelling and experimental validation of rapid pyrolysis of lignocellulosic biomass

Abstract

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.Considerable research has been devoted towards determining the kinetics of the pyrolysis of lignocellulosic biomass such as wood residues and agricultural waste. In this study, we have developed a finite element model (FEM) in order to simulate the coupled heat and mass transfer phenomena during pyrolysis. The resulting sets of partial differential equations were then solved simultaneously using the COMSOL Multiphisics software package. This numerical modelling and simulation approach helped the visualization of the process. In this work, cylindrical sections of birch wood biomass were pyrolysed in a laboratory-scale thermal desorption unit. The influences of final pyrolysis temperature, and pyrolysis holding time on the biochar yields were investigated. Results showed that with increase in time and temperature, the yield of total pyrolysis products decreased. On the other hand, higher pyrolysis temperatures and holding times resulted in the increase of char content in the wood for fast pyrolysis. A technique to maximize the amount of char in the product was also identified through by optimizing the parameters within the temperature range of this study