DESTABILIZATION OF WATER IN BITUMEN EMULSION BY WASHING WITH WATER

Abstract

ABSTRACT In order to get more information about the mechanism of stabilization of water-in-diluted-bitumen emulsion, bitumen diluted with toluene (10%, 25%, and 50% in volume) was "washed" using different amounts of water (0.20% in volume). The washing water was emulsified and then separated by high-speed ultra-centrifugation. The supernatant was then used to create a second w/o emulsion with the addition of new water. Stability of the new emulsion was measured in terms of the water separation rate under a low centrifugal force It has been found that a very stable w/o emulsion was obtained in original diluted bitumen. However, after the diluted bitumen was pre-washed with a few per cent of water, the second emulsion became unstable. This indicates a significant effect of pre-washing with water on emulsion stability, possibly through the removal of emulsion stabilizing agents. Based on analytical results such as surface tension, and FTIR spectra, it appears that a small fraction of bitumen, mostly polar compounds such as carbonic acids and other oxygen-containing compounds, are responsible for the emulsion stabilization. Emulsion stability decreases with increasing volume of washing water but increases with the bitumen concentration.