Dynamic behavior of an internally heat-integrated distillation column (HIDiC)

This paper reports the analysis of the energy saving for design of an internally heat integrated distillation column (HIDiC) conducted in the second-phase of Japanese national research project for energy conservation in multicomponent petroleum distillation. The practical commercial scale distillation column separating cyclopentane from a multicomponent mixture consisting of mainly C5 hydrocarbons was selected as a target of the application of HIDiC technology. By choosing the compression ratio, the number of the theoretical stages, and the heat transfer rate as design and operating variables, temperature, pressure, flow rates, and composition profiles were computed as well as the reboiler heat duty of the HIDiC by Pro/II. The energy consumption of the HIDiC was compared with that of the practical conventional distillation column operated at the minimal reflux ratio. It was confirmed that at least 25 % of energy saving can be achieved by means of the HIDiC system. A pilot plant of the HIDiC was designed based on the results obtained in this study. It was constructed and has been in operation since 2005. The pilot HIDiC shows more than 50 % of energy savings compared to the conventional distillation column, validating the analysis of this study.