A reduced order rate based model for distillation in packed columns: Dynamic simulation and the differentiation index problem

• Published in: Chemical engineering science 2012-01, Vol.68 (1), p.401-412
• Main Authors: Bonilla, J., Logist, F., Degrève, J., De Moor, B., Van Impe, J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical engineering; Computer simulation; Differentiation; Distillation; Dynamic simulation; Dynamics; Exact sciences and technology; Heat and mass transfer. Packings, plates; High-index DAE; Mathematical analysis; Mathematical modeling; Mathematical models; Model reduction; Packed columns; Structure exploitation
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2011.09.051

This paper presents a rigorous dynamic rate based model suitable for simulation of distillation of mixtures in packed columns. The model equations are described in detail considering structure exploitation at simulation level in order to alleviate the large number of states involved in the model description. Moreover, this kind of model may leads to differential-algebraic equations with a differentiation index higher than one. Here this issue is analyzed and a differentiation-index reduction procedure based on the incidence of model states in the Jacobian and the properties of the model dynamics is proposed. This procedure allows for a simplified index-1 model with a reduced stiffness so that dynamic simulation can be performed with off-the-shelf solvers. ► We introduce a reduced order rate based model for distillation in packed columns. ► It is shown that despite the large-scale model, structure can be efficiently exploited. ► The high differentiation index problem is studied. ► A procedure based on structural analysis of model Jacobian is proposed for index reduction. ► Model dynamic simulation and parameter sensitivity analysis for the proposed model is presented.