Development of Torrefaction Technology for Solid Fuel Using Renewable Biomass

Fossil fuel sources such as coal, crude oil and natural gas would eventually get exhausted and their price continuously fluctuates. During the past four decades, many researches have tried to find alternate fuel resources to satisfy the worldwide increasing energy demand as well as to minimize dependence on fossil fuels. Among many possible alternate fuel sources, agriculture biomass residues exhibit most promising possibility due to their inherent characteristics in storing solar energy and amenability in subsequent conversion into convenient solid, liquid and gaseous fuels. Torrefaction is a thermal method for the conversion of biomass operating in temperature range of 200–300°C under atmospheric conditions in the absence of oxygen. Agricultural crop residues that are abundant in the Philippines such as coconut leaves, cogongrass and rice husk were utilized to produce solid fuel by torrefaction for use as alternative source of energy. The key torrefaction products were collected and analyzed. Combustion characteristics of both torrefied and untorrefied biomass were investigated. Torrefaction of the biomass significantly improved the heating value, proximate compositions also improved and were comparable to coal and combustion characteristics were superior making it more suitable for fuel applications. The design of the torrefaction process was researched and developed.