(80c) Effect of Stripping Factor on Distillation Column Efficiency

Distillation is one of the oldest methods for separating binary and multicomponent liquid mixtures and comprises about 95% of all the separation processes in the chemical and processing industries. Being an energy intensive process, distillation typically contributes up to 50% of capital and operating costs of a plant. Therefore, even small improvements in distillation operation and design would have a significant impact on the costs due to the scale of operation.

The point efficiency plays an important role in estimating tray and column efficiencies during scale up of distillation columns. Most data used to develop efficiency models were obtained from distillation tests under total reflux conditions. However, commercial distillation columns are generally operated in a non-total reflux mode of operation. Therefore, the current efficiency models may not be truly representative of actual efficiencies observed in the field. There is a need to develop reliable efficiency models using data on both total reflux and non-total reflux conditions.

This study aims to fill the gap in the existing literature and provide new experimental data based on non-total reflux mode of operation. This is an extension of our earlier study that collected experimental data based on total reflux mode of operation. As part of this current study, a modified Oldershaw column was designed and installed. The Oldershaw column is capable of operating in both total reflux and non-total reflux modes of operation and provides simultaneous point efficiencies for rectification and stripping sections of the column. Since the stripping factor plays an important role in determining efficiencies in non-total reflux mode, the effect of stripping factor on distillation efficiencies was systematically investigated over several test systems covering a range of physical properties.