On the Stability of a Periodic Solution of Distributed Parameters Biochemical System

International audienceThis paper studies the stability of periodic solutions of distributed parameters biochemical system with periodic input Sin(t). We prove that if Sin(t) is periodic then the system has a periodic solution that is input to state stable when small perturbations are acting on the input concentration Sin(t)

Integrated design and control of chemical processes : part I : revision and clasification

[EN] This work presents a comprehensive classification of the different methods and procedures for integrated synthesis, design and control of chemical processes, based on a wide revision of recent literature. This classification fundamentally differentiates between “projecting methods”, where controllability is monitored during the process design to predict the trade-offs between design and control, and the “integrated-optimization methods” which solve the process design and the control-systems design at once within an optimization framework. The latter are revised categorizing them according to the methods to evaluate controllability and other related properties, the scope of the design problem, the treatment of uncertainties and perturbations, and finally, the type the optimization problem formulation and the methods for its resolution.[ES] Este trabajo presenta una clasificación integral de los diferentes métodos y procedimientos para la síntesis integrada, diseño y control de procesos químicos. Esta clasificación distingue fundamentalmente entre los "métodos de proyección", donde se controla la controlabilidad durante el diseño del proceso para predecir los compromisos entre diseño y control, y los "métodos de optimización integrada" que resuelven el diseño del proceso y el diseño de los sistemas de control a la vez dentro de un marco de optimización. Estos últimos se revisan clasificándolos según los métodos para evaluar la controlabilidad y otras propiedades relacionadas, el alcance del problema de diseño, el tratamiento de las incertidumbres y las perturbaciones y, finalmente, el tipo de la formulación del problema de optimización y los métodos para su resolución

Benelux meeting on systems and control, 23rd, March 17-19, 2004, Helvoirt, The Netherlands

Book of abstract

Mathematical modelling of fixed bed reactors

Consideration is given to the solution of the highly exothermic fixed bed catalytic reactor problem taking into account heat and mass transfer resistances inside the catalyst pellets and across the external fluid film as well as radial temperature and oonoentration gradients in the fluid phase. Comparison of the model with the simpler quasi homogeneous repreaenation is made. In the region where the quasi homogeneous case predicts temperature "run-away", the added refinements assume some importance. Very significant; differences in behaviour are predicted. Indeed no temperature "run-away" is apparent. Inolucling simply a film mass and heat transfer resistance is no guarantee that temperature "run-away" will not be predicted. In fact, it is the particle diffusive resistance whioh is the main factor limiting the temperature effects. Since the region of temperature "run-away" is often in the practical range it is essential to use a more detailed model for design such as the one described here, especially if optimal operating conditions are being sought. Even on large digital computers, the computation time is excessively long if the sets of differential equations are solved simultaneously. By examining the intrapartiole equations in detail for a practical range of physical properties and operating conditions, it is shown that they may be reduced, to a lumped parameter form. While still retaining the characteristics of the general problem, the lumped parameter approximation can be solved in a substantially shorter time, thus taking its use in optimization and control studies feasible