Raphaële Thery

Modelling of a dynamic multiphase flash: the positive flash. Application to the calculation of ternary diagrams

A general and polyvalent model for the dynamic simulation of a vapor, liquid, liquid-liquid, vapor-liquid or vapor-liquid-liquid stage is proposed. This model is based on the τ -method introduced as a minimization problem by Han & Rangaiah (1998) for steady-state simulation. They suggested modifying the mole fraction summation such that the same set of governing equations becomes valid for all phase regions. Thanks to judicious additional switch equations, the τ -formulation is extended to dynamic simulation and the minimization problem is transformed into a set of differential algebraic equations (DAE). Validation of the model consists in testing its capacity to overcome phase number changes and to be able to solve several problems with the same set of equations: calculation of heterogeneous residue curves, azeotropic points and distillation boundaries in ternary diagrams. Topical Heading Process System Engineering

Infinite/infinite analysis as a tool for an early oriented synthesis of a reactive pressure swing distillation

The study contributes to the characterization of an original reactive pressure swing distillation system. The methyl acetate (MeAc) transesterification with ethanol (EtOH) to produce methanol (MeOH) and ethyl acetate (EtAc) is shown as illustrative example. The streams outside the units are evaluated by the ∞/∞ analysis to provide insights on the process behavior. Two simpler systems with recycling stream are also presented. The ∞/∞ analysis allows checking the interrelation of the system streams without any column design consideration. Unfeasible regions, low limit values, multiplicity regions, discontinuities, control difficulties, recommendable operation conditions and column profile combinations are predicted and discussed. All these information are useful to establish an early and suitable system design strategy.

Infinite/infinite analysis as a tool for an early oriented synthesis of a reactive pressure swing process

Abstract The study deals with the methyl acetate (MeAc) transesterification with ethanol (EtOH) to produce methanol (MeOH) and ethyl acetate (EtAc). A first screening has shown that a reactive pressure swing process would have the best performance regarding this reaction. This study provides insights on this process behaviour and control via the infinite/infinite analysis. The infinite/infinite analysis allows checking the interrelation of the system streams without any column design consideration. Unfeasible regions, low limit values, multiplicity regions, discontinuities, control difficulties, recommendable operation conditions and column profiles combination are predicted and discussed. All this information is useful to establish an early and suitable system design strategy.

A Sequential and hierarchical approach for the feasibility analysis and the preliminary synthesis and design of reactive distillation processes

Abstract A procedure that combines feasibility analysis, synthesis and design of reactive distillation columns is introduced. The main interest of this methodology lies on a progressive introduction of the process complexity. From minimal information concerning the physicochemical properties of the system, three steps lead to the design of the unit and the specification of its operating conditions. This methodology which provides a reliable initialization point for the optimization of the process has been applied with success to different synthesis. The production of Methyl-Tert-Butyl-Ether (MTBE) is presented here as an example.

Decision-making tool for scheduling of batch processes: the dynamic hybrid simulation kernel

Abstract PrODHyS is a dynamic hybrid simulation environment, which offers extensible and reusable object oriented components dedicated to the modeling of processes. The purpose of this communication is to illustrate the potentialities of PrODHyS through the use of hybrid simulation for the scheduling of semi-continuous processes.

Object-oriented components for dynamic hybrid simulation of a reactive distillation process

Abstract PrODHyS (Process Object Dynamic Hybrid Simulator ) is an object-oriented environment for the hybrid dynamic simulation of chemical processes. The aim of this paper is to introduce a small part of the main reusable object components available in this library and to illustrate its potentialities through the modeling and the simulation of a reactive distillation column.