Lignocellulosic Biomass Solid Fuel Properties Enhancement via Torrefaction

Torrefaction, also known as mild pyrolysis, is often carried out between temperature ranges of 200 and 300oC in anoxic conditions. It is a type of thermo-chemical pre-treatment process applicable to biomass in order to convert it into compatible energy fuels. Torrefaction has favorable effects on biomass, which includes increasing its energy density and eliminating problems commonly associated with raw biomass such as high moisture content, hygroscopic behavior and low calorific value. In this study, torrefaction of agricultural residue, oil palm frond (non-woody biomass) and short rotation energy crop, Leucaena Leucocephala (woody biomass) were conducted in a horizontal tube furnace at five temperatures and holding time of 60 min. High heating values, elemental and proximate analyses results, thermal degradation profiles of torrefied fibrous products were compared to its raw forms. It was concluded that as torrefaction conditions became more severe, this led to a more qualified and energy-dense solid fuel with higher fixed carbon content, increased calorific values and reduced hydrogen and oxygen contents. The results gained from this study may provide basic information for torrefied products application in combustor and/or gasifier design.