A Petlyuk distillation column dynamic analysis: Hysteresis and bifurcations

Abstract

Thermally coupled distillation columns (TCDC) have proven to be a superior and feasible alternative compared to conventional distillation. However, their inherent system complexity presents optimization and operational challenges. In this work, we analyzed these problems from a different perspective: understanding the steady-state behavior by the means of a steady state and bifurcation analysis. This approach used a dynamic model programmed in Matlab 2019b and validated with Aspen Plus v8.8. The analysis demonstrated that the steady-state multiplicity is triggered by the magnitude of the internal flows and that the interlinking trays may develop isolated bifurcation branches. Moreover, it is shown that the “operational holes” or intermittent discontinuities in the TCDC steady states are formed by saddle-node bifurcations. This suggests that a non-smooth optimization algorithm is more suitable for TCDC design.