7-16: Are the existing methods for compositional analysis of ‘typical’ cellulosic feedstocks adequate to obtain an accurate mass balance for forest residues?

Forest/Forest Products residues represent a relatively abundant and, if handled properly, sustainable source of biomass. Due to the variability in structure and chemical composition of potential biomass sources such as hog fuel, bark, etc., one current challenge will be to obtain an accurate compositional analysis and mass balance of this material. The most commonly used methods for determining biomass composition have been historically derived from the pulp & paper and agricultural sectors. These methods tend to be semi-quantitative with the main objective being an assessment of forage digestibility or fibre characteristics (strength, brightness) respectively, rather than the quantification of individual biomass components. The biorefinery concept in many ways mirrors why a good material balance is required for oil refineries. In the case of petrochemicals, the high cost of the feedstock requires all fractions of the oil to be accurately quantified and utilized, which will undoubtedly be the same case for and future Biorefineries. Current “biomass material balance” procedures have generally been developed using “clean” cellulosic feedstocks such as pulp chips. However, when more heterogeneous feedstocks such as bark or hog-fuel are used, it is much more difficult to achieve a 100% material balance with components such as ash, extractives, etc., becoming more significant. The presentation will review current methods of both quantifying the chemical composition of biomass substrates and obtaining a representative material balance while discussing ways to refine these techniques so that they can be used with more heterogeneous biomass feedstocks.