PRODUCTION OF OXYGENATED FUELS FROM BIOMASS - IMPACT OF FEEDSTOCK STORAGE

Biomass pyrolysis oils were produced from stored biomass feedstocks by rapid pyrolysis in a fluidized bed reactor. The feedstocks used for t hese studies were switchgrass, corn stover, and hybrid poplar. The woo dy and herbaceous feedstocks were stored in chip piles and bales, resp ectively, unprotected in an open field for 6 months. At the end of the storage period. biomass samples were taken from the interior of bales and the centers of chip piles for pyrolysis studies. The materials we re ground to pass -20/+80 mesh and dried to less than 10% moisture con tent before pyrolyzing in the fluidized bed reactor. Pyrolysis was con ducted at 500 degrees C and with less than 0.4 s. vapor residence time . Total liquid yields were as high as 66% for the hybrid poplar and as low as 58% for the corn stover. Moisture content of the oils was betw een 10% and 13%. Gas and char/ash yields were 10-15% and 12-22%, respe ctively. The char/ash yields were feedstock dependent, but storage inf luence was significant for only the corn stover feedstock. Gas and liq uid yields were not influenced by storage time. The oils were highly o xygenated and had higher heating values (HHV) of 23-24 MJ/kg that decr eased slightly with storage time for all the feedstocks except the swi tchgrass. The oils, as currently produced, are high in ash and alkali metals. Ultimately, they will be upgraded and used as boiler and turbi ne fuels.