Biomass quality of some Poaceae species and possible use for renewable energy production in Moldova

Abstract

Biomass makes a major contribution to the world and nation’s renewable energy portfolio. Plant biomass represents stored energy that may be drawn upon on demand, can be converted into energy by combustion, producing cellulosic ethanol and biogas. Domestication of new species as dedicated energy crops may be necessary. Currently Poaceae species are the most commonly utilized herbaceous plants as raw material for the production heat energy by direct combustion process in Moldova. The objective of this research was to evaluate some physical and mechanical properties of dry biomass of the new Poaceae species: Miscanthus giganteus and Sorghum almum collected from the experimental land of the Botanical Garden (Institute), control variants - wheat straw, Triticum aestivum and corn stalks, Zea mays. The physical and mechanical properties of dry biomass were determined according to European Standards in the State Agrarian University of Moldova, the production of solid fuels - by the equipment developed in the Institute of Agricultural Technique „Mecagro” Chisinau. In the field it has been established that Miscanthus giganteus stems defoliated faster than Zea mays, the stems of Sorghum almum dehydrated rapidly. The bulk density of the milled chaffs by sieve 10 mm and 6 mm of the tested energy crops was 90-167 kg/m3 and 163-198 kg/m3 , respectively. The specific density of briquettes reached 740-923 kg/m3 , but the specific density333 of pellets – 1007-1262 kg/m3 . The Miscanthus giganteus was distinguished by high density, gross calorific value (19.3 MJ/kg) and low ash content (2.23%); Sorghum almum biomass moderately gross calorific value (18.6 MJ/kg) and ash content (3.71%); Zea mays high specific density of solid fuel (923 and 1124 kg/m3 ); wheat straw lowest bulk density and calorific value, and high ash content (4.93%). Miscanthus giganteus and Sorghum almum are promising energy crops for the production solid biofuel in Moldova.