The present work involves the development of a mathematical model to describe the pyrolysis of a single solid biomass particle. Generally, the phenomena governing the pyrolysis of a single biomass particle is based on both physical and chemical changes. The chemical changes include primary and secondary pyrolysis reactions, and both chemical and physical changes are controlled by the heat transfer phenomena. The proposed energy balance model equation takes into account the nonisothermal reaction of the biomass particle. The equation for the model is solved for a cylindrical pellet under a wide range of operating conditions. The numerical scheme employed is a finite difference, backward implicit scheme for the heat transfer equation and the Runge-Kutta 4th Order Predictor-Corrector method for the equations involving chemical kinetics. Results for various size particles have been obtained to predict, the temperature profile as a function of the radial distance at varying time intervals. The results obtained from the model are compared with experimental data from the literature.