Electronic Thesis and Dissertation Repository


Doctor of Philosophy


Chemical and Biochemical Engineering


Dr. Lars Rehmann


Fast pyrolysis is rapid thermal conversion process capable of transforming multiple feedstocks into various energy carriers, specifically pyrolysis oil, bio gas, and bio char. The oil phase is of high value due to its complex mixtures of organic molecules, along with large number of anhydrous carbohydrates, which can be easily transformed into glucose via acid hydrolysis. These carbohydrates can be either biocatalyzed into fuels and chemicals by microorganisms or converted after further treatment steps. However quantities of these carbohydrates in the oil are a function of feedstock composition and process parameters. The research presented in this thesis focuses on producing a detoxified sugar fraction for biofuels production. Cold water, solvent extraction, acid hydrolysis and neutralization were utilized to upgrade pyrolysis oil to procure a fermentable substrate. Development of a high throughput analysis to assess fermentability was realized utilizing microtiter plates. The effect of biomass composition on sugar concentrations present in the oil phase were studied by demineralizing switch grass and corn cobs, with weak and strong acid solutions. Upgrading of the resulting oils was performed and fermentation to ethanol was realized expanding and demonstrating the application of the process to different biomasses. Ethanol production in both cases was compared to well established processes which led to improvements in the upgrading configuration. These improvements were applied in lipid production by an oleaginous yeast. Effects of inhibitory compounds on lipid productivity and biodiesel quality was investigated. Quality of derived biodiesel was in the range of diesel fuel standards. The conclusions from this research provide guidance for the utilization of inexpensive residual biomass in pyrolysis based biorefineries for the production of biofuels and chemicals as an alternative to crude oil derived products.