Laroche I, Wu X, Masliyah J H, Czarnecki J
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.
J Colloid Interface Sci. 2002 Jun 15;250(2):316-26. doi: 10.1006/jcis.2002.8369.
In the commercial bitumen extraction operation, dynamic and static interaction forces between bitumen drops in water determine the likelihood of desirable bitumen coalescence at different process stages. These dynamic and static forces were measured using colloidal particle scattering and hydrodynamic force balance techniques, respectively. In the former technique, dynamic interactions are studied through droplet-droplet collision trajectory measurement. In the latter technique, the static attractive forces between droplets are determined when a doublet is separated with a known and adjustable hydrodynamic force. The dynamic force measurement implies the presence of rigid chains on bitumen surfaces. The mean chain lengths for deasphalted bitumen at pH 7, whole bitumen at pH 7, and whole bitumen at pH 8.5 are 50, 78, and 41 nm, respectively. However, the static force measurement indicates much shorter mean chain lengths (<9 nm) in these three bitumen systems. Shorter chain length indicates weaker repulsive force. This finding of a much weaker repulsion between bitumen droplets under static conditions has important implications on the commercial bitumen extraction operation.
在商业沥青萃取操作中，水中沥青滴之间的动态和静态相互作用力决定了在不同工艺阶段所需沥青聚结的可能性。这些动态和静态力分别使用胶体颗粒散射和流体动力平衡技术进行测量。在前一种技术中，通过液滴 - 液滴碰撞轨迹测量来研究动态相互作用。在后一种技术中，当用已知且可调节的流体动力将双联体分开时，确定液滴之间的静态吸引力。动态力测量表明沥青表面存在刚性链。pH值为7时脱沥青沥青、pH值为7时全沥青以及pH值为8.5时全沥青的平均链长分别为50、78和41纳米。然而，静态力测量表明这三种沥青体系中的平均链长要短得多（<9纳米）。较短的链长表明排斥力较弱。这一关于静态条件下沥青滴之间排斥力弱得多的发现对商业沥青萃取操作具有重要意义。
