Creating Thermochemical and Catalytic Carbon Emission Reduction Technologies from Biomass

Abstract

The increase in greenhouse gas emissions has created adverse consequences for the environment and the livelihood of human civilization. This rise in greenhouse gas emissions dates to the first industrial revolution and was caused by the reliance on high carbon footprint feedstock and processes. Biomass has been identified as one of the potential platforms for mitigating the emissions of carbon by either removing it through biogenic sequestration or used as alternative feedstock in creating technological pathways to replace fossil fuel-derived feedstock. This research focuses on developing biomass-based technologies and catalysis that can help in lowering greenhouse gas emissions. This thesis work explores two different biomass-based technologies (Biomass Torrefaction and Burial and hydrogenation of lignin phenol for renewable caprolactone production) and the characterization of a new catalyst called ion gel catalytic condenser.Biomass torrefaction and permanent burial technology (BTB) is an alternative method that uses biomass as a starting point of carbon dioxide capture and converts it into stable char for permanent sequestration. A Monte Carlo model assessed the full process and determined the average efficiency of carbon removal at 0.81 tCO2e/tonne-biomass and the cost of carbon removal is less than $200/tCO2e for 95% of scenarios. The long-term permanence of the torrefied carbon and the feasibility of large-scale deployment of the technology to combat climate change was discussed.The selective hydrogenation of lignin-derived alkyl phenols is an important step in the production of renewable caprolactone for recyclable polyesters/polyurethane. The selective hydrogenation of alkyl phenols was studied using an up-flow packed bubble column by assessing the effect of reaction parameters, such as temperature, pressure, and residence time on the reaction performance under both integral and differential conditions. The reaction selectivity was found to be determined by the surface coverage of the alkyl-phenols on the catalyst surface that inhibits secondary hydrogenation. The low apparent barrier and faster initial rate of phenyl ring hydrogenation help in maintaining high reaction selectivity at lower reaction temperature conditions. Evaluation of this reaction under flow conditions brings insights to create a feasible biomass-based route that can replace current process technology. The creation of sustainable biomass-based processes can be further improved by improving the current catalyst design by creating a new type of catalyst that can be modified in situ to achieve new performance in reaction rate and selectivity. Understanding the thermal stability of the material is crucial to ensure the feasibility of this new catalyst to be deployed in commercial reactors. Thermogravimetric analysis of the ion gel showed that the ion gel’s chemical integrity degraded earlier than the physical mass of the material when analyzed at 300°C. Thermal stability measurement at 200°C showed the ion gel chemical and physical integrity remaining intact for >48 hours.