Impact of straw fractional composition on briquette quality

Abstract

Growing prices for traditional energy resources make alternative energy sources and extraction methods attractive in this situation. Straw unused in agricultural production technology as grain production residue can be successfully used for biofuels, heat and electricity production. The obtained grain and straw ratio per hectare is from 0.8 up to 1.2. Assuming that the average grain yield in Lithuania is approx. 2.9 t·ha-1, with one million hectares under cereals, 3200 thousand tons of cereal straw are yielded in Lithuania. Considering the fact that, without damage to the soil, other agriculture industries can utilize in average up to 12-15 % of straw yield; therefore annual straw fuel potential in Lithuania is about ~400 thousand tons and the energy equivalent is approximately ~100 toe. Straw is a “messy” fuel, so before usage for biomass burning in a heat plant it must be processed technologically. For this purpose biomass is crushed, dried, pressed into briquettes or pellets. Using the briquetting technology, the energy value of straw volume is increased by 13 times. This option facilitates the transportation of straw, improves their technological properties. The Institute of Energy Engineering and Biotechnology, Aleksandras Stulginskis University has studied the influence of fractional composition of triticale straw chaff on the briquette quality. The briquetting machine “Biomasser BSO6” was used to form straw briquettes from homogenous 50, 40, 30, 20 mm length, mixed 50 mm and 20 mm long chopped straw and the changes in the size and density of the produced briquettes were investigated. The research has shown that briquettes with the best physical - mechanical properties were formed from chopped straw of different lengths, the density of the briquettes was 747.59 m-3, and they showed the highest stability after pressing.