Chemical characterization of Cynara cardunculus Var. altilis biomass with low ashes content to obtain solid biofuel

Lines of cardoon (Cynara cardunculus L. var. altilis DC suitable for biomass production are under selection at CNR - ISAFOM Catania, with the main objective of characterizing ashes, chlorine and alkali, that are the main compounds responsible of combustion chamber corrosion. In this work one new line of cultivated cardoon was evaluated, selected for the low amount of ashes, to be used for heating. This trial was carried out at Syracuse, South Sicily, in 2007-2009 growing seasons. The selected genotype Line C5 was grown, under low inputs management, using a plant density of 8 plants m-2. At harvest, August 2009, on twenty plants for each of the three agronomic replications the number of heads, the fresh biomass weight and its partitioning (leaves, stalks, capitula and achenes) were determined. Grain lipid substances were extracted and quantified. The sample of leaves, stalks, heads and defatted flour of achenes were at first chipped and the content of dry matter, ashes, chlorine, sulphur and alkali evaluated. On average biomass production per plant was 175 g plant-1 DM, leaves represented 24%, stalks 25%, heads 48% and achenes about 3% on aboveground biomass. The plant dry matter content was about 970 g kg-1 fw, nitrogen 90 g kg-1 DM, and ashes 40% g kg-1 DM chlorine, sulphur and alkali resulted very low with 3.5, 3.0 and 2.7 g kg-1 DM respectively. The oil content of the grain was 235 g kg-1 DM. The present results show that the Line C5 is characterized by a low amount in ashes, even if other studies are necessary, in different environments and under different agricultural managements, to confirm the present results.