title: Fast Pyrolysis Behavior of Banagrass as a Function of Temperature and Volatiles Residence Time in a Fluidized Bed Reactor.
abstract: A reactor was designed and commissioned to study the fast pyrolysis behavior of banagrass as a function of temperature and volatiles residence time. Four temperatures between 400 and 600°C were examined as well as four residence times between ~1.0 and 10 seconds. Pyrolysis product distributions of bio-oil, char and permanent gases were determined at each reaction condition. The elemental composition of the bio-oils and chars was also assessed. The greatest bio-oil yield was recorded when working at 450°C with a volatiles residence time of 1.4 s, ~37 wt% relative to the dry ash free feedstock (excluding pyrolysis water). The amounts of char (organic fraction) and permanent gases under these conditions are ~4 wt% and 8 wt% respectively. The bio-oil yield stated above is for 'dry' bio-oil after rotary evaporation to remove solvent, which results in volatiles and pyrolysis water being removed from the bio-oil. The material removed during drying accounts for the remainder of the pyrolysis products. The 'dry' bio-oil produced under these conditions contains ~56 wt% carbon which is ~40 wt% of the carbon present in the feedstock. The oxygen content of the 450°C, 1.4 s 'dry' bio-oil is ~38 wt%, which accounts for ~33 wt% of the oxygen in the feedstock. At higher temperature or longer residence time less bio-oil and char is recovered and more gas and light volatiles are produced. Increasing the temperature has a more significant effect on product yields and composition than increasing the volatiles residence time. At 600°C and a volatiles residence time of 1.2 seconds the bio-oil yield is ~21 wt% of the daf feedstock, with a carbon content of 64 wt% of the bio-oil. The bio-oil yield from banagrass is significantly lower than from woody biomass or grasses such as switchgrass or miscanthus, but is similar to barley straw. The reason for the low bio-oil yield from banagrass is thought to be related to its high ash content (8.5 wt% dry basis) and high concentration of alkali and alkali earth metals (totaling ~2.8 wt% relative to the dry feedstock) which are catalytic and increase cracking reactions during pyrolysis.
authors: Hawaii Natural Energy Institute, University of Hawaii at Manoa, Honolulu, HI, 96822, United States of America.
authors: Trevor James
authors: TJ
authors: Morgan
authors: Hawaii Natural Energy Institute, University of Hawaii at Manoa, Honolulu, HI, 96822, United States of America.
authors: Scott Q
authors: SQ
authors: Turn
authors: Combustion Research Facility, Sandia National Laboratories, Livermore, California, 94550, United States of America.
authors: Anthe
authors: A
authors: George
mesh_terms: D056804:Biofuels; D018533:Biomass; D019149:Bioreactors; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D031782:Pennisetum / Q000378:metabolism*; D010938:Plant Oils / Q000378:metabolism*; D014867:Water / Q000737:chemistry
chemical_list: D056804:Biofuels; D010938:Plant Oils; D014867:Water