Insight into torrefaction of woody biomass: Kinetic modeling using pattern search method

Abstract

Torrefaction aroused as a promising pretreatment technique that can improve the fuel properties and thermochemical conversion performance of biomass. The kinetics of biomass torrefaction is fundamental for the investigation of torrefaction reaction mechanisms, and the simulation and optimization of torrefaction processes. The commonly used empirical reaction model has some theoretical drawbacks in describing the kinetics of biomass torrefaction. In this study, the torrefaction kinetics of beech wood was studied using thermogravimetric analysis (TGA) at isothermal temperatures of 493, 523 and 553 K. The nth-order kinetic model was presented to analyze the kinetic experimental data at all torrefaction temperatures simultaneously. The pattern search method was used to optimize the kinetic parameters of the nth-order model for biomass torrefaction. Predicted results from the nth-order model with the optimal kinetic parameters were compared with the experimental data and indicated that the nth-order model satisfactorily predicted the experimental data of beech wood torrefaction at different torrefaction temperatures.