See more from this Session: S4-S8 Graduate Student Poster Competition
Monday, October 17, 2011
Henry Gonzalez Convention Center, Hall C, Street Level
Bioenergy plants such as high-energy sorghum, corn and rice residue, and switchgrass can be thermo-chemically converted by pyrolysis to produce bio-oil, synthesis gas from non-condensable gases (NCG), and biochar. The biochar fraction can be recycled back to the production field to improve soil structure, water holding capacity, aggregation, water infiltration, and nutrient levels. While various publications have demonstrated the beneficial effects of pyrolysis biochar on soil physical properties, there has been relatively little published data on the recovery of mineral nutrients from biochar. Some research had indicated that the majority of the mineral nutrients that are conserved during the pyrolysis process reside within the biochar. This study investigates the recovery of key plant-essential nutrients and other minerals from the bio-oil, synthesis gas, and biochar co-products produced from two separated fluidized-bed reactors under controlled operator conditions. Nutrient mass balances, on a biomass basis, will be calculated for comparison of the two reactors efficiency in the recovery of the mineral nutrients. Preliminary studies using a fixed-bed slow pyrolysis reactor revealed temperature and inert gas flow-rate influences (p=0.05) with average phosphorus recoveries of 61% from the biochar on a biomass basis and less than 5% recovery from the bio-oil and gas fractions. Similar studies using a relatively modern fluidized-bed fast pyrolysis reactor revealed temperature and inert gas flow-rate influences (p=0.05) with average phosphorus recoveries of 51% for biochar and less than 5% recovery from the bio-oil and gas fractions on a biomass basis. Recoveries for potassium, calcium, and magnesium will also be presented.