The accuracy of the distillation efficiency correlations plays a critical role in cost-effectively designing distillation columns. Liquid viscosity is considered to be a major factor that influences distillation efficiency through its contribution to the liquid-phase mass transfer coefficient, interfacial area of mass transfer, and vapor and liquid phase residence times. Nearly all of the distillation efficiency correlations in the literature were developed or validated on the basis of efficiency data at liquid viscosities less than 1.5 mPa s. However, distillation at liquid viscosities greater than 1.5 mPa s is encountered in several cases in the chemical process industry. In this paper, the evaluation of three different tray and point efficiency correlations using Oldershaw column data at liquid viscosities from 0.2 to 4.2 mPa s is presented. In addition, we propose an improved point efficiency correlation, based on the Duss and Taylor correlation, with a modified liquid viscosity exponent for the liquid-phase mass transfer coefficient. The proposed correlation was validated with commercial sieve tray efficiency data and Oldershaw column data. This proposed correlation will aid in the cost-effective design of distillation columns, especially at elevated liquid viscosities.

蒸馏效率相关性的准确性在经济高效地设计蒸馏塔中起着至关重要的作用。液体粘度被认为是影响蒸馏效率的主要因素，因为它对液相传质系数，传质界面面积以及气相和液相停留时间有贡献。基于液体粘度小于1.5 mPa s的效率数据，开发或验证了文献中几乎所有的蒸馏效率相关性。但是，在化学过程工业中，在数种情况下会遇到液体粘度大于1.5 mPa s的蒸馏。本文介绍了使用Oldershaw色谱柱数据在液体粘度为0.2至4.2 mPa s时对三种不同塔板效率和点效率相关性的评估。另外，我们基于Duss和Taylor相关性，提出了一种改进的点效率相关性，其中液相传质系数的液体粘度指数经过修改。所建议的相关性已通过商业筛塔效率数据和Oldershaw色谱柱数据进行了验证。拟议的相关性将有助于蒸馏塔的经济高效设计，尤其是在液体粘度较高的情况下。