Metallopetroporphyrines as process indicators: Separation of petroporpyrins in Green River oil shale pyrolysis products

Product oils from the LLNL Hot-Recycled-Solids (HRS) retorting process were separated to isolate and concentrate the metallopetroporphyrins. A modified column chromatography procedure developed previously for heavy crude oils and tar sand bitumens was used. The fractions were then examined by UV-vis spectroscopy to determine categories of porphyrins and other related metal-containing species. No porphyrins were found in the hexane fraction (least polar fraction); Ni porphyrins were found in the methylene chloride fraction (moderate polar fraction); and a free-base porphyrin-like species was found in the methanol fraction (the most polar fraction) of some of the oils. The CH2CI2 fractions were further examined to quantify the amount of porphyrins detected. In the whole oil samples examined, ~ 40 wt % of the Ni was found as Ni petroporphyrins. The vacuum residua of two product oils had ~ 20 wt % of the Ni bound as Ni porphyrins indicating that the vacuum distillation process destroys porphyrins.