Comparison of Different Methods To Determine the Surface Wettability of Fine Solids Isolated from Alberta Oil Sands

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• 作者：Cheng Wang ; Mirjavad Geramian ; Qi Liu ; Douglas G. Ivey ; Thomas H. Etsell
• 刊名：Energy & Fuels
• 出版年：2015
• 出版时间：June 18, 2015
• 年：2015
• 卷：29
• 期：6
• 页码：3556-3565
• 全文大小：522K
• ISSN：1520-5029

文摘

The wettability of fine solids in Alberta oil sands is one of the most important factors affecting nonaqueous bitumen extraction and subsequent solvent recovery from the extraction gangue. However, there is some controversy as to which method is most suitable for wettability determination of fine solids isolated from the oil sands. In this paper, four different methods鈥攊.e., particle partition, static sessile drop contact angle coupled with penetration time, Washburn capillary rise, and film flotation鈥攚ere investigated and compared in order to determine suitable methods to examine the wettability of these fine solids. Two model samples, high-purity kaolinite (hydrophilic) and bitumen-treated kaolinite (hydrophobic), were used to investigate the suitability of the above four methods. These methods were then used to measure the surface wettability of fine solids isolated from the oil sands (marine clay) after toluene extraction, either untreated or heated at 400 掳C for 2 h. The results showed that the Washburn capillary rise method was not applicable. In addition, the particle partition and static sessile drop contact angle coupled with penetration time methods had some deficiencies and were not very suitable to determine the wettability of fine solids isolated from the oil sands. The film flotation method was determined to be the most appropriate method, because (i) it was sufficiently sensitive to distinguish solid surface hydrophilicity and hydrophobicity; (ii) it could quantify the hydrophilicity and hydrophobicity, based on the measured 鈥渕ean critical surface tension鈥? and (iii) it could be used to determine the surface heterogeneity of the solids, based on the standard deviation of the measurements. By using the film flotation method, the mean critical surface tensions of fine solids was >68.1 mN/m, while that of the heat-treated solids was >72.0 mN/m, and the standard deviation of the critical surface tensions of the floating particles (0鈥?5.9 wt %) for fine solids was 40.5 mN/m, which indicated that heat treatment caused the fine solids to become more hydrophilic and the hydrophobicity of the fine solids was heterogeneous. In addition to direct application of the four standard methods, we have further developed the methods and gained some new insights into them.