Abstract
The aim of this study is to estimate rough chemical formulae of lignin constituents of selected biomass samples (beech wood, spruce wood, walnut shell, hazelnut shell, corncob, wheat straw and sunflower shell). Isolation of original lignin from a lignocellulosic material is considerable trouble. Various fuel characteristics, such as moisture, ash, hemicelluloses, cellulose, lignin and extractive contents of different biomass species were determined on ash-free dry weight and extractive-free dry weight basis to find out the relationship, if any, between ash and extractive content with the higher heating value. The extractive content is an important parameter directly affecting the heating value. Extractives raised the higher heating values of the biomass samples.