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

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 C₂–C₁₃ and C₂–C₁₄, whereas the Geokinetics retort water contained C₂–C₁₀, the 150 Ton retort water C₂–C₁₀, and Omega-9 retort water C₂–C₁₄ 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 C₂–C₇ straight-chain dicarboxylic acids, but those from C₈–C₁₂ were present. The Omega-9 retort water contained all the straight-chain dicarboxylic acids, C₂–C₁₂, that were identified, whereas the 150 Ton sample contained only C₂ and C₄ dicarboxylic acids, and the Geokinetics sample C₂–C₄ and C₈–C₁₂ acids. The implications of the results in pyrolysis of oil shale kerogen are discussed.