Dissertation
THERMAL PRETREATMENT OF A HIGH LIGNIN AND HIGH ASH FERMENTATION RESIDUE FOR GASIFICATION
Doctor of Philosophy (PhD), Washington State University
01/2015
Handle:
https://hdl.handle.net/2376/111589
Abstract
As concerns about the use of petrochemical fuels continue to increase, research into the utilization of renewable biomass for fuels has witnessed greater and greater attention. Biofuels can be generated through thermochemical or biological pathways, but maximizing the overall net carbon conversion efficiency will be necessary to attain economic feasibility for industrial biorefineries. Fermentation of lignocellulosic feedstocks such as corn stover gives a high yield and selectivity to alcohols that can be used as fuels, but an unfermentable fraction is generated that contains a high concentration of lignin and ash. While the residue can be thermochemically converted to liquid fuels through gasification, a number of problems exist when processing it in this manner. The lignin may prematurely melt and plug the feed lines, and the ash may melt and agglomerate the fluidized bed. This research investigates the use of a thermal pretreatment process that may be able to alleviate these problems by increasing the softening point of the material and removing liquid lignin intermediates that may serve as an adhesive during the agglomeration process. A residue from the SSF process was acquired and gasified in a fluidized bed reactor to investigate the bed agglomeration mechanism and provide a baseline for further experiments. Thermal pretreatment of the material was then performed at various times and temperatures, and the resultant materials were characterized to determine the mechanisms responsible for the increased softening point observed. A large quantity of the residue was then thermally pretreated at the optimal time and temperature to generate enough feedstock for a test in the fluidized bed reactor. This pretreated material was able to be fed into the reactor without pelletization, and the cooling nitrogen required to be co-fed was reduced by half. However, bed agglomeration continued to occur, and gas production was reduced by one third. Gasification experiments in a small scale reactor showed that the gas production decrease was not due to the change in the gasification behavior of the fixed carbon, the fixed carbon of thermally pretreated material showed comparable gasification behavior to the untreated residue.
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Details
- Title
- THERMAL PRETREATMENT OF A HIGH LIGNIN AND HIGH ASH FERMENTATION RESIDUE FOR GASIFICATION
- Creators
- Daniel Trusler Howe
- Contributors
- Manuel Garcia-Perez (Advisor)Michael Wolcott (Advisor)Armando McDonald (Committee Member)Richard Zollars (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 185
- Identifiers
- 99900581525201842
- Language
- English
- Resource Type
- Dissertation