Nutrient Leaching from Switchgrass for Biofuel: Effects of Extraction Concentration, Temperature and Solvent

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Henderson, Chad
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University of Guelph

The amount of nutrients in biomass will affect combustion efficiency. Homogenized samples of spring harvested switchgrass cv. Cave-in-Rock were ground to 1 mm, treated at varied switchgrass concentrations (25, 50, 75 and 100 g/L), temperatures (20, 40 and 60 ˚C) and initial mineral concentrations in several water solvents (distilled, tap and well water). After solvent removal, percent weights of nitrogen, calcium, phosphorus, potassium, magnesium, sulphur and chlorine in the switchgrass were analysed. Switchgrass concentration of 100 g/L reduced phosphorus leaching by 46 % and potassium by 54 % compared to 25 g/L. Higher temperature had a significant effect on the amount of potassium and sulphur that could be removed. Solvent type had a significant effect on leaching for calcium, phosphorus, potassium, magnesium, chloride and sulphur, but the best water type for leaching varied. Spring harvested switchgrass of this cultivar does not need to be further leached to meet combustion standards.

biofuel, switchgrass, direct combustion, nutrient leaching