Hydrothermal Liquefaction Biocrude Compositions Compared to Petroleum Crude and Shale Oil

Abstract

We provide a direct and detailed comparison of the chemical composition of petroleum crude oil (from the Gulf of Mexico), shale oil, and three biocrudes (i.e., clean pine, microalgae Chlorella sp., and sewage sludge feedstocks) generated by hydrothermal liquefaction (HTL). Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) reveals that HTL biocrudes are compositionally more similar to shale oil than petroleum crude oil and that only a few heteroatom classes (e.g., N1, N2, N1O1, and O1) are common to organic sediment- and biomass-derived oils. All HTL biocrudes contain a diverse range of oxygen-containing compounds when compared to either petroleum crude or shale oil. Overall, petroleum crude and shale oil are compositionally dissimilar to HTL oils, and >85% of the elemental compositions identified within the positive-ion electrospray (ESI) mass spectra of the HTL biocrudes were not present in either the petroleum crude or shale oil (>43% for negative-ion ESI). Dir...