Dynamic simulation for internally heat-integrated distillation columns (HIDiC) for propylene–propane system

Abstract

This paper reports a dynamic simulation study of the internally heat-integrated distillation column (HIDiC) using equilibrium-based models. First, three different HIDiC structures, i.e. an ideal HIDiC, a HIDiC with a pre-heater, and a HIDiC with a reboiler, are analyzed by control degrees of freedom (DOF). The reboiler is considered to be a necessary part of the HIDiC from DOF analysis, thermodynamic analysis, and engineering judgment. Then, a heuristic HIDiC control configuration including a bottoms reboiler control is proposed. A modular structured simulator for dynamic distillation columns using MESH equations is developed. The simulator also considers: (1) variable column pressure on each tray of the rectifying section, (2) dynamic vapor holdup, and (3) dynamic energy balance. In addition, the SRK equation of state is employed for estimating thermodynamic properties. A typical medium-pressure HIDiC for separation of propylene and propane explored by Olujic et al. [Olujic, Z., Sun, L., de Rijke, A., & Jansens, P. J. (2006). Conceptual design of an internally heat-integrated propylene–propane splitter. Energy, 31, 3083] is adopted as numerical examples for dynamic simulation studies.