Barbara Drygaś, Joanna Depciuch, Czeslaw Puchalski, Grzegorz Zaguła
Abstract. Torrefaction is the process of drying biomass at high temperatures in order to transform it into biofuels with properties and composition resembling carbon. The impact of high temperature breaks the chains of hemicellulose, lignin and cellulose and degrades the biomass to simpler organic compounds. The aim of this publication was to specify the impact of the duration of the heat treatment on the stability of biomass structures such as lignocellulose illustrated with examples of selected species of conifers. The research material consisted of shoot tips of Junniperus sabina and Picea abies. The material used in the process was air-dried, dried at 150oC and torrefied at temperatures of 200, 250 and 300oC in a LECO camera – TGA 701 apparatus for 30 minutes. Fresh needles and their torrefied products were measured spectroscopically using FTIR Vertex 70v made by Bruker. Microscopic photographs of samples were taken in the scales 10 μm, 20 μm, and 50 μm using the TESCAN VEGA3 scanning electron microscope. The unprocessed plant material did not differ significantly from one another – the FTIR spectra of both plants exhibited the same functional groups. The biomass heat treatment led to significant changes in its chemical composition and topographic changes in the obtained biochars.
Key words: torrefaction, biomass, FTIR spectra, changes, biochars