The evaluation of the quality indices of phytomass from energy crops and agricultural residues

Abstract

The objective of this research was to evaluate the quality indices of the solid dry phytomass from energy crops Miscanthus giganteus 'Titan', Silphium perfoliatum ‘Vital’, Sorghum bicolor, var. saccharatum 'SAȘM1' and agricultural residues - stems of Brassica napus oleifera and Pisum sativum collected in the experimental plot of the NBGI Chişinău. It has been found that elemental composition the collected dry phytomass was 41.36-50.00% carbon, 4.32-6.14% hydrogen, 0.22- 1.37% nitrogen, 0.03-0.10% sulphur, 2.18-5.66% ash and gross calorific value varied from 18.2 to 19.6 MJ/kg phytomass. The solid dry phytomass contained 361-520 g/kg cellulose, 191-320 g/kg hemicellulose, 83-122 g/kg acid detergent fibre and the estimated theoretical ethanol yield averaged 410-592 L/t organic dry matter. The studied energy crops were characterized by optimal quality indices of phytomass and can serve as feedstock for the production of pellets and cellulosic bioethanol. The agricultural residues have higher content of ash, nitrogen, sulphur and lower concentration of structural carbohydrates and energy value, which make them suitable to be used as a part of a diverse mix with biomass from woody species.