Thermodynamic analysis of biomass gasification: Including torrefaction as a thermal pre-treatment

Biomass is currently the fourth largest energy source and its share in the future world energy supply is expected to increase. Traditionally, it has been combusted in fires, ovens and boilers. This book addresses the question how biomass may be used more efficienty and economically. Through gasification of biomass, produced gas could be increasingly used in modern devices such as gas turbines and fuel cells or in chemical reactors. This work analyzes the thermodynamic efficiency of gasification, with emphasis on the effect of feedstock composition. A promising possibility to enhance the fuel properties of woody biomass prior to gasification is experimentally explored, namely torrefaction. This technology comprises a thermal pre-treatment, in which wood is roasted at temperatures in the range of 230-300 degrees C. Novel concepts for integration of wood torrefaction and gasification are highlighted, which may contribute to the development and introduction of advanced gasification processes.