Modelling and experimental studies on pyrolysis of biomass particles

A simple mathematical model has been developed to describe the pyrolysis of a single biomass particle. A fully transient analysis involving a kinetic model coupled with heat transfer model has been presented. The kinetic model consists of both primary and secondary pyrolysis reactions while the heat transfer model includes diffusive, convective and radiative modes of heat transfer. Fourth-order Runge–Kutta–Gill method is used to solve the kinetic model, while implicit Finite Volume Method (FVM) with Tri-Diagonal Matrix Algorithm (TDMA) is employed to solve the heat transfer model. The kinetic parameters and heat of reaction are estimated by Levenberg Marquardt nonlinear optimization technique. A general-purpose FORTRAN program is developed to solve the model equations and estimation of parameters. Experimental investigations are carried out for wood fines and cylinders in an electrically heated reactor. The model predictions for temperature and mass loss histories are in excellent agreement with the experimental results. The model is also validated with published experimental results. Finally, the effects of temperature and particle size on pyrolysis time and yield of final char have been analyzed with model simulation.