(251d) Spinning Band Distillation of Pyrolysis Oil Phenolics

Fast pyrolysis of biomass produces organic bio-oils, which can be refined into finished hydrocarbon fuels. Oils of relatively low oxygen content (<15 wt%) can be distilled, leaving behind a solid carbonaceous residue. We’ve demonstrated how extraction can separate the distillates into a hydrocarbon fraction and a phenolics fraction, the latter consisting predominantly of one-ring phenolics. We’ve also demonstrated the feasibility of continuous flash distillation for bulk bio-oils and hydrocarbons. For phenolics, more careful distillation methods are warranted to produce desired purities.

In this talk, we discuss the purification and utilization of partially deoxygenated bio-oil fractions using spinning band distillation. We utilized a spinning band column distillation system, designed to perform at 200 theoretical plates. Catalytic (HZSM-5) pyrolysis bio-oils from switchgrass biomass first underwent extraction directly, producing a phenolic fraction and a hydrocarbon fraction. Subsequently, the phenolic fraction underwent a preliminary flash distillation before spinning band distillation, in order to remove residues. Spinning band distillation resulted in fractions with more than 80 wt% phenol (the balance was o-cresol), which can be purified by recrystallization to >93 wt%. We will also discuss the composition of other fractions characterized using NMR. While we’ve distilled hydrocarbon fractions in the past, none have produced a coke residue fraction. We distilled the hydrocarbon fraction and converted this specific residue into a high-purity coke product. Structural and electrical properties will be presented, including results from XRD, resistivity testing, and XRF.