Biomass Torrefaction: Improving the Fuel Properties of Biomass

Global energy demand has been rising and will continue to rise at a rapid pace. To encourage the use of alternative energy sources in the United States, many States have introduced policies that require an increased production of energy from alternative renewable energy sources. Biomass is a promising alternative energy source that can potentially replace coal in power plants. Torrefaction is an important step in using biomass as fuel source. The actual process of torrefaction involves heating biomass in the absence of an oxidizing agent and under atmospheric pressure. The product is a dried biomass that has a higher mass energy density, is hydrophobic, and is more uniform, in composition, compared to unprocessed biomass. Also, the grindability (ie, resistance to crushing) characteristics of torrefied biomass greatly improve and are comparable with coal and coke. The effect of torrefaction on heating value, grindability, and hydrophobicity of biomass will be discussed.