Biomass quality of hemp, Cannabis sativa L., and prospects of its use for various energy purposes

Abstract

Plant biomass is an important renewable energy source in the world, and its importance has increased in regional and national energy strategies. The main objective of this research has been to evaluate the dry biomass quality of hemp, Cannabis sativa L., collected from the experimental field of the National Botanical Garden (Institute), Chişinău as feedstock for the production cellulosic ethanol and solid bio fuel, namely briquettes. Corn stalks, Zea mays, were considered as control. The analysis of the chemical composition suggested that the dry matter of the whole hemp plants contained 556 g/kg cellulose, 309 g/kg hemicellulose and 105 g/kg acid detergent lignin, but corn stalks - 417 g/kg cellulose, 250 g/kg hemicelluloses and 82 g/kg acid detergent lignin. The theoretical ethanol yield from structural carbohydrates averaged 628 L/t in hemp substrates, as compared with 485 L/t in corn substrates. The bulk density of the milled chaffs of tested biomass, varied from 100 to132 kg/m3, the gross calorific value - from 17.8 to 19.0 MJ/kg, the ash content - from 2.1 to 4.4%. The Cannabis sativa biomass was characterised by high gross calorific values and low ash content. The specific density of hemp briquettes reached 867 kg/m3. Hemp, Cannabis sativa, may serve as multi-purpose feedstock for renewable energy production.