Corrosion assessment of pyrolysis/hydrothermal liquefaction bio-oils: effects of upgrading treatments by catalytic hydro-de-oxygenation (HDO) in supercritical methanol/ethanol
Bio-oil derived from fast pyrolysis and hydrothermal liquefaction of lignocellulosic biomass usually contains a high oxygen content (30-50%), leading to a relatively low heating value, high viscosity and poor stability. Moreover, the presence of organic acids in crude bio-oil results in low pH value and hence corrosion of the reactor materials (steel or alloys). To date, a wide range of bio-oil upgrading techniques have been developed, especially hydro-de-oxygenation (HDO), widely employed to remove oxygen of the crude bio-oil via water formation. By far, not much research has been done on the reactor materials corrosion during HDO upgrading. In this research, upgrading of the crude bio-oil by HDO in supercritical methanol or ethanol will be investigated, not only to develop cost-effective processes for producing high-quality bio-fuels, but to explore corrosion mechanism of metallic alloy materials during bio-oil HDO or in contact with the crude and upgraded bio-oils.