Experimental studies on the upgrading of fast pyrolysis oil to liquid transportation fuels

Environmental concerns and possible future shortages have boosted research on alternatives for fossil derived liquid transportation fuels. Fast pyrolysis oil, obtainable from biomass in yields up to 70%-wt, is considered a promising second generation biofuel. However, as such, the oil is not suitable for applications in in-stationary internal combustion engines due to its high oxygen content (ca. 40%-wt) and low pH (ca. 2.5). We have carried out experimental research on the upgrading of fast-pyrolysis oil by hydrodeoxygenation. In this process, the fast pyrolysis oil is treated with hydrogen in the presence of a heterogeneous catalyst with the formation of water and a hydrocarbon-like product. A wide variety of heterogeneous catalysts have been explored and the product properties of the resulting products have been determined. It was shown that supported Ru catalysts (e.g. Ru on carbon) are good alternatives for classical hydrotreating catalysts like sulphidised CoMo and NiMo on alumina. Products with an oxygen content less than 8%-wt. could be obtained in yields up to 50%-wt. The products contain significant amounts of hydrocarbons like (linear) alkanes and aromatics. Engine tests with the HDO oil, HDO-diesel blends and certain fractions of the HDO oil are in progress and will be reported as well.