August 1, 2012.
The conversion of non‐food sources of biomass to liquid transportation fuels could be a viable alternative to non‐renewable petroleum based fuels with high carbon dioxide emissions if the process can become cost effective. One of the problems with the catalytic pyrolysis as a thermochemical pathway to biomass based fuel production is the accumulation of carbonaceous deposits (aka coke) that can completely deactivate catalysts over time. A multiple technique approach was used to analyze four different stages of coke development. Solid samples of coke were analyzed via multiple techniques; elemental, 13C NMR, TGA, and SEM analysis confirmed the presence of two types of coke molecules and low (.5) hydrogen to carbon ration at all stages of deactivation. This suggests that coke is very similar to coal and could potentially be intercepted by hydrogen donor molecules in the pyrolysis process to produce more desirable hydrocarbon molecules. GC/MS results from carbon‐tetrachloride (CCl4) and methylene‐chloride (CH2Cl2) extractions indicate that coke molecules formed during fast pyrolysis (500‐600°C) are insoluble which was unexpected.
National Renewable Energy Laboratory (NREL)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013 and Grant No. 0833353. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).