Use of Torrefaction and Solvent Extraction To Produce Ash-less Biomass as a Solid Fuel Feedstock for Co-firing

As a result of the characteristics of biomass, biomass exploitation as a secondary fuel feedstock in co-firing is only technically and economically acceptable in the range of 5–10% (w/w). In this study, torrefaction and solvent extraction as biomass pretreatments were conducted to address feedstock limitations, making a larger share of biomass for co-firing feasible. The physical and chemical characteristics of the solvent-extracted biomass were investigated using proximate analysis, ultimate analysis, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Biomass torrefied at 200, 250, 270, 300, and 330 °C was extracted by nonpolar organic solvent 1-methylnaphthalene at 350 °C for 1 h to produce ash-less biomass (extracted biomass). A dry, raw, woody biomass was also extracted under the same conditions to see the effect of torrefaction on the characteristics of extracted biomass and residue biomass. The result shows that solvent extraction was effective in producing ash-less biomass, wi...