Differential Evolution Approach for Obtaining Kinetic Parameters in Nonisothermal Pyrolysis of Biomass

Abstract

Pyrolysis, a first step in the biomass gasification, is the thermal decomposition of organic matter under inert atmospheric conditions, leading to the release of volatiles and formation of char. As pyrolysis is a kinetically controlled reaction, kinetic parameter estimation is very important in the design of pyrolysis reactors. In the proposed kinetic model of this study, the kinetic scheme of biomass decomposition by two competing reactions giving gaseous volatiles and solid charcoal is used. Four different models are proposed based on different possible relation of activity of biomass with normalized conversion. The corresponding kinetic parameters of the above models are estimated by minimizing the square of the error between the reported nonisothermal experimental data of thermogravimetry of hazelnut shell and simulated model predicted values of residual weight fraction using differential evolution (DE), a population-based search algorithm. Among the four different models proposed in this study, the model in which rate of change of activity of biomass with normalized conversion proposed as a function of activity itself gave the best agreement with the experimental data.