This paper proposes a thermodynamical pseudo Hamiltonian formulation of Continuous Stirred Tank Reactor model in which takes place some chemical reaction. This is done both in the isothermal and non isothermal cases. It is shown that the Gibbs free energy and the opposite of entropy can be chosen as Hamiltonian function respectively. For the non isothermal case, the so called Interconnection and Damping Assignment Passivity Based Control method is applied to stabilize the system at a desired state. For this general reaction scheme, the control problem is shown to be easy to solve as soon as the closed loop Hamiltonian function is chosen to be proportional to the so called thermodynamic availability function. Simulation results based on a simple first order reaction and operating conditions leading to multiple steady states of the CSTR are given to validate the proposed control design procedure.

In this paper, the thermodynamic availability function is used as a Lyapunov function for the practical derivation of non linear control laws for the stabilization of a large class of CSTRs far from the equilibrium. The strict convexity of the availability function is guaranteed as long as one of the extensive variables is fixed. In this study, we consider liquid mixture with constant volume, the constraint on the volume being insured by perfect regulation of the outlet flow of the CSTR. Several control laws are then derived which insure global asymptotic stability, exponential stability or simple asymptotic stability. These control laws are discussed regarding the magnitude and the dynamic variations of the control variable. It is shown that the availability function can be split into two parts : one corresponds to the mixing term and depends on mole numbers only and the other depends on both temperature and mole numbers. The two parts are positive and the second one is chosen as a new Lyapunov function. The use of this new Lyapunov function insures smooth variations of the control variable. An exothermal, first order chemical reaction leading to multiple steady-state operating points of the CSTR illustrates the proposed theory.

A one-dimensional physically motivated dynamic model of a twin-screw extruder for reactive extrusion has been developed. This model predicts the transient and stationary behavior of the extruder for pressure, filling ratio, temperature, and molar conversion profiles as well as residence time distribution under various operating conditions. The model consists of a cascade of perfectly stirred reactors that can be either fully filled with backflow or partially filled according to the operating conditions. Each reactor is described by the reactant concentrations and the melt temperature. A piece of barrel and screw, described by their temperature, is associated with each reactor. Living polymerization of ε-caprolactone with tetrapropoxytitanium as the initiator is chosen as an example of application. The flow representation aspect of the model is validated by using experimental residence time distributions. Validation of the model is derived from simulation results as well as comparison with experimental data.

In this paper we present a bond graph model of a continuous stirred tank reactor which represents the reaction kinetics as well as the heat and mass transport phenomena in the reactor. The consequences of reticulation of the phenomena and of the systematic use of the power conjugated variables on the formulation of the thermodynamic properties, the reaction kinetics and the energy and mass transport are shown. A classical example of chemical reaction is chosen to illustrate this approach: the equilibrated reaction of hydrogen and iodine in hydrogen iodide.

No abstract

No abstract

No abstract

No abstract