Miscanthus biomass quality composition and methods of feedstock preparation for conversion into synthetic diesel fuel

Abstract

When developing various technologies designed for biomass conversion into biofuels, it is important to establish the suitability of raw material of lignocellulotic, non-food plants such as Miscanthus, whose biomass has a good energy potential. Biomass productivity, quality and its suitability for processing under more northern climatic conditions are important factors to be considered. Experiments were aimed to estimate quality and technological parameters of Miscanthus growing, harvesting and processing into synthetic diesel, to evaluate chemical, physical and mechanical properties of biomass and to determine energy consumption necessary for biomass preparation for conversion into synthetic diesel. The study object was biomass of Miscanthus (Miscanthus × giganteus Greef et Deu) produced under Lithuanian and German climate conditions. Miscanthus harvested in the autumn produced up to 9.42 t ha-1 dry matter (DM) yield, which was significantly higher in the treatments fertilised with a higher nitrogen rate. The content of cellulose (413–456 g kg-1 DM) and hemicellulose (204–236 g kg-1 DM) was very similar at all fertilisation levels. The highest content of lignin (117 g kg-1 DM) was established in the treatments fertilised with 120 kg ha-1 N. The spring-harvested Miscanthus biomass had significantly lower moisture content and the yield was significantly lower, too. While preparing the biomass as feedstock for synthetic diesel the greatest reduction in moisture content (to 8.59 ± 1.38%) occurred when Miscanthus biomass was chopped, pre-dried and milled, and particles larger than 2 mm accounted for the largest share. The energy use for chopping of autumn-harvested biomass was lower and chopping efficiency was higher compared with the spring-harvested biomass. The composition of major components of synthetic fuel from Miscanthus biomass was very similar to that of mineral diesel.