Red Mud as a Catalyst for the Upgrading of Hemp-Seed Pyrolysis Bio-oil

摘要

Hemp-seed pyrolysis bio-oil was upgraded in a batch laboratory-scale pressure reactor under 800 psi (cold) hydrogen gas at 350-365 ℃ using a non-alkaline, nontoxic Fe_xO_v/SiO_2/TiO_2 catalyst [reduced red mud (RRM)] obtained by the reduction of red mud with HOAc/HCCOH. The upgraded liquid obtained was separated into stable organic and aqueous phases. Comparative analyses between the crude oil and the organic and aqueous phases of upgraded products showed that the RRM-upgraded bio-oil is composed of fewer carbonyl-containing and polar oxygenated compounds but more saturated hydrocarbons. The upgraded oil phases are less viscous than the native oil and stable against resin formation for at least 60 days. The catalytic activity of RRM is related to its ability to catalyze both deoxygenation and cracking reactions that convert reactive components (aldehydes, ketones, and carboxylic acids), which make the oil unstable over time, into less reactive deoxygenated products.