Submitted to: Journal of Analytical & Applied Pyrolysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2010
Publication Date: 1/19/2011
Citation: Compton, D.L., Jackson, M.A., Mihalcik, D.J., Mullen, C.A., Boateng, A.A. 2011. Catalytic pyrolysis of oak via pyroprobe and bench scale, packed bed pyrolysis reactors. Journal of Analytical & Applied Pyrolysis. 90:174-181.
Interpretive Summary: This research determined that catalysts affected the pyrolysis of woody biomass to form potential bio-based, renewable chemicals. Our mission is to develop new, value added uses for commodity crops, crop waste, and biomass in an effort to mitigate the effects of climate change through the development of domestically derived, bio-based chemicals and products. We determined that using commercially available solid inorganic catalyst, modified using a proprietary binding and extruding method to form pellets, changes the liquid and gas compounds typically obtained from the heating of biomass in the absence of oxygen (pyrolysis). It was found that specific catalysts enrich the liquid and gas products with desired chemicals while lowering the yield of undesirable chemicals. Our results are important because what we discovered in our small, bench-scale system is guiding the decision of our scientific and industrial collaborators who will attempt similar experiments in larger, pilot-plant scale reactors. These larger scale experiments will determine the practicality and economic feasibility of using solid inorganic catalysts for the production of bio-based, renewable chemicals on industrial scales.
Technical Abstract: The pyrolytic conversion of oak sawdust at 500°C in flowing He over eight proprietary catalysts is described and compared to the control bed material, quartz sand. The reactions were conducted and compared in two reactors, an analytical, ug-scale pyroprobe reactor and a bench, g-scale packed bed reactor. The catalysts examined were modified hydrocrackers, dealuminated-zeolite Y, beta-zeolite, hydrotalcite, mordenite, and MCM-41. The packed bed reactor allowed the collection of three bulk product fractions, char, liquid, and gas, all of which could not be obtained from the ug-scale pyroprobe reactions. The catalysts effect on the mass balance of the bulk fractions tended toward more chars and less liquid compared to the sand control. The catalysts' effects on the liquid products obtained in both reactors shifted away from acetic acid, furfural and higher molecular weight phenolics obtained with sand to lower molecular weight aromatics. This halved the total acid number of the liquid fraction and raised the pH by up to 1.4 units. The modified catalysts' effects on the gas products from both reactors did not follow a specific trend. Instead, specific catalysts were able to enrich specific gas species up to a factor of 15 while suppressing the formation of others compared to the sand control. Two catalysts, beta-zeolite and hydrotalcite, were regenerated and recycled up to five times with no loss of activity.