Theses and Dissertations Collection

Lignocellulosic biomass has several advantages that set it apart as a convenient source for renewable energy. Among the conversion technologies, thermochemical decomposition of biomass by fast pyrolysis has shown to be a simple, cost-efficient route for producing valorized liquid (bio-oil) and solid (biochar) products. Bio-oil has potential for heat, biofuels, and pharmaceutical applications, while biochar can be used as a soil amendment and remedy water eutrophication. This dissertation focuses on assessing free-fall fast pyrolysis reactor design through the implementation of experiments that assess several biomass-to-bioproduct pathways. To do so, a review on thermochemical biomass conversion technologies and pathways geared towards increasing fuel properties of liquid bio-oil was performed. Both critical and systematic reviews made evident the need for a single-step, intensified pathway for lignocellulosic-based fuel blendstocks production. Next, the potential of a mixed fast and slow pyrolysis process for the conversion of several feedstocks into bio-oil and biochar was evaluated. The effects of feedstock type on the physical and chemical properties of bio-oil and biochar attributes were assessed with the help of various characterization techniques. The desirable characteristics of pine-derived bio-oil led to it being selected for further upgrading experiments. A comparison of γ-alumina as a catalyst for in-situ and ex-situ catalytic fast pyrolysis in a free-fall reactor configuration was examined using pinewood flour. Efficiency and the effect of methanol as a direct quenching fluid for fractionation were also examined. γ-Alumina was shown to successfully decrease acidic compounds and increase esters in the bio-oil. Bio-oil produced from ex-situ catalytic pyrolysis presents a promising oil with the highest average yield, high phenolic content, and thermally stable properties. Fractions condensed in methanol exhibited the highest thermal stability and esterification potential; however, they still possessed relatively high amounts of acidic compounds. It was concluded that the use of γ-alumina with methanol impingers for fractionation could potentially produce an oil high in small chain esters and low in acids. Also, the use of γ-alumina as a catalyst support for hydrodeoxygenating metal catalysts could result in an inexpensive route for biomass-to-hydrocarbon fuels production. Also, a sustainability study on the market opportunity and environmental benefits of converting cattle manure to nutrient-rich biochar on-site, using a portable refinery unit, was conducted. Techno-economic and life cycle assessments were performed to assess the feasibility. Converting cattle manure, using the presented strategy and process near the collection sites could address upstream and midstream sustainability challenges and stimulate the biochar industry.