Optimal Design and Operation of Four-Product Dividing-Wall (Kaibel) Distillation Column

摘要

Due to the increased market competition, many chemical industries try to optimize their operations by maximizing productivity and minimizing operational cost, mainly energy consumption. Distillation operation alone accounts for a significant amount of the world’s energy consumption since it is widely used in refineries and petrochemical industries. It has been estimated that approximately 3% of the world’s energy consumption is utilized by this distillation operation alone [1]. This energy consumption can be greatly reduced by using an efficient complex distillation column configuration, such as a fully thermally coupled distillation column or divided-wall distillation column, over conventional arrangements. The divided-wall column (DWC) offers potential energy and capital investment savings. For multi-product separation, conventional distillation column configurations (direct, indirect and distributed sequences, etc.) require a greater number of heat exchangers, distillation columns, etc., compared with complex distillation column arrangements (side stripper, side rectifier, fully thermally coupled distillation column and divided-wall distillation column). Also, compared with conventional column configurations, complex distillation configurations lead to lower capital investment and energy consumption as well. However, design and operation remain a challenge due to the large number of design and operational degrees of freedom. In this study, it was shown that energy savings of up to 23% can be achieved by using a four-product divided-wall distillation column (Kaibel) compared with conventional column arrangements, Table 1. This work demonstrates the steady-state and dynamic behavior of a Kaibel distillation column using commercial simulation software i.e., Aspen HYSYS. Three different mixtures (Alcohols, Hydrocarbons, and Aromatics) are used to conduct the study and the comparison.