Detection of Volatile Organic Compounds in Froth Multiphase Systems from Oil Sands Operations Using a Headspace GC-MS Method

Degradation of air quality due to oil sands operations is one of the largest concerns for stakeholders and regulators. Volatile organic compounds (VOCs) released from tailings ponds are an important contributor to poor air quality. Current government regulations impose a limit on hydrocarbon losses to the froth treatment tailings at 4 barrels per 1000 barrels of dry bitumen, produced. However, considering the scale of bitumen production, atmospheric pollution from allowable VOC emissions is still problematic. One source of solvent loss to tailings ponds is solvent trapped in rag layers formed during froth treatment (a multiphase system that sometimes develops at the interface between the diluted bitumen and water). It would be useful to have a method for directly determining solvent loss in rag layers as support to efforts to optimize solvent recovery from froth treatment tailings. In this paper, analytical methods for the direct determination of solvent content in multiphase waste streams from oil sand froth treatment have been developed using headspace sampling combined with gas chromatographic separation and mass spectroscopic detection. The respective detection limits for heptane, toluene, octane, and p-xylene in the water "layer are 0.1, 0.4, 0.03, and 0.4 ppm. The detection limits for heptane, toluene, octane, and p-xylene in. the rag layer and oil are all approximately 1 wt %. The respective detection limits for naphtha in water, rag layer, and oil are 0.5 ppm, 6 wt %, and 6 wt %.