Evaluation of Giant Knotweed and Miscanthus as Perspective Energy Plants and Assessment of Produced Biofuel Quality Indicators

Abstract

Giant knotweed (Fallopia sachalinensis) was chosen as a perspective energy plant because it is not a soil demanding plant and belongs to the most efficient herbs in Central Europe as regards high biomass yield. Miscanthus (Miscanthus sinensis) was chosen as a control one. Knotweeds are comparable to wood briquettes and pellets because of their similarparallel mechanical and thermal features. These plants grow in forest environment with an approximate yield productivity of 15 t ha-1 d.b. (dry basis). Experimental research investigations were performed in the laboratories of Aleksandras Stulginskis University. Giant knotweed and miscanthus biomass was cut, chopped, milled and granulated with a small capacity granulator (250–300 kg h-1). Quality parameters of plant preparative and use for energetical objectives were determined. Plant chaff and mill fraction compositions were determined, and quality indicators of the produced pellets were measured – moisture content, density, resistance to compression, elemental composition, ash content and calorific value, also bulk density, fall and natural slope angles. Moisture content reached 7.8 ± 0.8 %; pellet density was 1227.3 ± 48.6 kg m-3. Resistance to compression of giant knotweed pellet was 850 N. Determined ash content was 4.3 ± 0.01 %, and net calorific value of knotweed dry mass was of sufficient height and reached 18.96 ± 0.28 MJ kg-1. Bulk density reached 509.9 kg m-3, natural slope angle was 31.7 0 and fall angle was 49.3 0.