Assessment of Stage 1 in a Novel Bio-Oil Upgrading Process: Catalytic Hydrotreating
Date
2018-11-13
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Abstract
The increasing awareness of global warming and depletion of conventional fossil fuel reserves has motivated the study of alternative fuel sources to fulfil the increasing worldwide demand of fuels. One promising alternative is the production of fuels using lignocellulose-derived bio-oils that would not compete with the human food chain. However, this type of bio-oil remains a challenge due to its high acidic oxygen content that results in corrosiveness and low energy density compared with crude oils. Therefore, the present MSc. research focuses on the study of the first stage of a novel catalytic upgrading approach that involves two different hydrogen-addition processes. First, a mild hydrotreating process is carried out to reduce the oxygen content in the bio-oil. Then, catalytic steam cracking (CSC), where hydrogen is produced by splitting water molecules, is used to obtain lighter products from the hydro-treated oil. The main focus of this research is to optimize the hydrotreating process. The effect of the process variables such as operating pressure, temperature and space velocity, on the product quality was evaluated, finding that the best quality hydrotreated product was obtained at 345 °C, 0.2 h-1, 1400 psig, and increasing the temperature beyond 345 °C at these conditions resulted in the appearance of fine solids dispersed in the synthetic product. Additionally, a comparison of different catalyst formulations was done, finding that acidity is needed in the catalyst to carry out hydrodeoxygenation reactions. It was also found that the two main compounds contributing to the acidity of the bio-oil are carboxylic acids and phenols, the latest with a minor contribution. By hydrotreating, it was possible to achieve a Total Acid Number (TAN) reduction of 100 % and a maximum of 28 % reduction of the phenols content. A high quality hydrotreated bio-oil with much reduced oxygen content, low viscosity and higher energy density was produced in this work.
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Keywords
Bio-oil, Total Acid Number, Hydrotreating, Catalytic Upgrading, Hydrodeoxygenation
Citation
Scheele Ferreira, E. M. (2018). Assessment of Stage 1 in a Novel Bio-Oil Upgrading Process: Catalytic Hydrotreating (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/34509