A Review on the Thermochemical Pretreatment of Lignocellulosic Biomass for the Production of Coal-grade Solid Biofuel

Thermochemical pretreatment or torrefaction of biomass is rapidly gaining attention because of simple operation, efficacy, and potential to produce valuable solid fuel. Torrefaction of lignocellulosic biomass is reviewed with the purpose of understanding the present state-of-the-art and future prospects. The following aspects have been discussed: biomass selection, optimization of engineering parameters, characterization of solid, liquid, and gaseous products and finally comparison with coal so that torrefied biomass may be blended with coal and utilized in a pulverized coal-fired furnace to produce electricity.