Interaction of furfural and hexadecane as bio-oil and plastics pyro-oil model compounds with non-thermal plasma processing as a route to in-situ hydrogen donor upgrading of bio-oil

Bio-oil upgrading by deoxygenation with a hydrogen donor has been investigated using a model bio-oil compound (furfural) and a model hydrocarbon (hexadecane) typically produced from plastics pyrolysis as the hydrogen donor. Upgrading has been investigated using a non-thermal plasma reactor system with the presence of hexadecane to improve bio-oil quality by raising the H/C ratio. The effect of input power on product yield, oil and gas composition has been investigated. There was little synergistic interaction between furfural and hexadecane in the absence of plasma. However, introduction of the non-thermal plasma, and increasing the input power for the furfural: hexadecane mixture resulted in a greater yield of gas components, along with the production of single ring aromatic and mono-oxygenated oil compounds, while dual-oxygenated compounds in the oil were reduced. There was a positive synergy for most light hydrocarbons, with higher input plasma power leading to higher positive synergy percentages. Conversely, the synergistic effect for most heavy hydrocarbons was negative, suppressing the formation of higher molecular weight oil compounds, which intensified with higher input plasma power levels. This phenomenon may be attributed to high-energy electrons in the non-thermal plasma environment colliding with volatile components of the feedstock, aiding in deoxygenation and the production of light hydrocarbons.