Fingerprinting and characterization of carboxylic acids in in-situ oil shale retort and process waters by capillary column gas chromatography-mass spectrometry

Abstract

Six important in-situ oil shale retort and process waters have been analysed for carboxylic acids by capillary column gas chromatography-mass spectrometry. A fingerprint or profile was obtained for Occidental boiler blowdown process water, retort water and heater-treater process water; Geokinetics retort water, and Laramie Energy Technology Center Omega-9 and 150 Ton retort waters. The results clearly show significant differences in that each retort or process water contains various mono-, di-, branched, keto-aliphatic and aromatic carboxylic acids. The Occidental retort and process waters contained straight-chain monocarboxylic acids from C 2–C 13 and C 2–C 14, whereas the Geokinetics retort water contained C 2–C 10, the 150 Ton retort water C 2–C 10, and Omega-9 retort water C 2–C 14 acids. Variations among the retort waters and process waters were more important for the normal dicarboxylic acids. The Occidental retort and process water contained no C 2–C 7 straight-chain dicarboxylic acids, but those from C 8–C 12 were present. The Omega-9 retort water contained all the straight-chain dicarboxylic acids, C 2–C 12, that were identified, whereas the 150 Ton sample contained only C 2 and C 4 dicarboxylic acids, and the Geokinetics sample C 2–C 4 and C 8–C 12 acids. The implications of the results in pyrolysis of oil shale kerogen are discussed.