HERBAL PLANTS PREPARATION FOR BIOFUEL AND ANALYSIS OF PELLETS PROPERTIES

Abstract

For research investigations were used the herbal unconventional energy plants – cup plant (Silphium perfolatium L.) and Virginia mallow (Sida hermaphrodita), which were grown in Lithuanian Research Centre for Agriculture and Forestry, and the knotweed (Reynoutria), which grew naturally in the forest glade. The productivity of these herbaceous plants are very high – 7-20 t ha^-1 dry mass yield. Plants were cut by manual motorized chainsaw and chopped by drum chopper. Prepared chaff was milled by hummer mill and produced mill was granulated by small capacity granulator (250-300 kg ha^-1). In presented work were determined investigated plant mill and pellet properties. After investigation of mill fractional composition was determined, that the smallest mill fraction was produced of milled knotweed plant stems: the biggest mill fraction accumulated on sieve with holes 0.25 mm diameter – 45.4 %, and dust – 46.7 %. The cup plants mill biggest fraction accumulated on sieve with holes 0.63 mm (37.6 %), Virginia mallows mill – on sieve with holes 0.5 mm (45.9 %). Also it was determined pellets quality parameters: humidity, density, ash content and calorific value. Determined biggest humidity was of knotweed – 22.3 %, it was too big, but produced knotweed pellets was sufficient hard and burning efficiency was a normal. The pellet density was significant high and ranged from 945.5 to 1072.3 kg m^-3 dry matter (DM). The ash content of investigated plant pellets varied from 4.28 to 9.96 %, and was too high compared with wood. The average calorific value of investigated energy plants pellets varied from 16.8 to 17.7 MJ kg^-1. Using laboratory equipment INSTRON 5960 were determined pellet disintegration force: the biggest force was for knotweed plant – 847 N, and about two times less for cup plant (463 N) and Virginia mallow (344 N). After analysis of test results it should be concluded, that knotweed pellets are sufficiently resistant to static force.