Nonlinear control of a batch emulsion polymerization reactor

International audienc

Process Control: Theory and Applications

A wide range of identification and control methods applicable to processes are accompanied by typical comparable examples, encouraging you to make comparisons. The initial classical approach to continuous control by transfer functions will be of enormous benefit, whether you are a student beginning in control or an engineer in industry, who up until now has only had a land contact with control. The more advanced material on discrete control and the state space control, as well as nonlinear control and observers, requires minimal previous knowledge, enabling you to make better use of performing techniques. Progressively it introduces concepts of increasing difficulty, allowing a less brutal tuition of theories and control methods. For each topic, the theories, techniques and algorithms are presented in detail, with numerous references. The consideration of the same problems by different approaches will provoke a deep understanding. It includes all necessary explanations for your complete understanding of the subject and examples that you can reproduce to master the different techniques. Broad coverage creates an important synthesis on the majority of aspects of control giving you a complete view of control theory and possible applications within the field. Different levels of reading are possible, opening this powerful source of information to students, engineers, academics and researchers alike

A simplified model for real gas expansion between two reservoirs connected by a thin tube

International audienc

Modeling of hydrogen isotopes separation in a metal hydride bed

International audienc

Optimal linear PI fuzzy controller design of a heat exchanger

International audienceThis study aims at improving the control of a heat exchanger, described by a partial differential equation, by optimizing a linear proportional–integral fuzzy controller. The design of the controller is based on the use of a finite-dimensional approximate model, of high order, derived by spatially lumping the infinite-dimensional model of the heat exchanger. The design procedure consists to optimize the scaling factors of the linear fuzzy controller, by solving an unconstrained optimization problem issued from the simplification of a formulated constrained optimization where the objective function is an integral error measure, and the constraints are the relationships between fuzzy and conventional PID gains. The formulated unconstrained optimization problem is then solved using jointly the Matlab Optimization Toolbox and Simulink. Through simulation, the performances of the heat exchanger are evaluated, and the obtained results show that the fuzzy controller produces improved control performance with respect to the conventional controller

Boundary geometric control of a counter-current heat exchanger

International audienceThe present article deals with the boundary geometric control of a counter-current heat exchanger whose control is designed considering a model based on two partial derivative equations describing the variations of internal and external temperatures. The objective consists in controlling the internal fluid temperature, at the heat exchanger outlet, by manipulating the jacket temperature at its inlet boundary in spite of the variation of the temperature of the internal fluid at the heat exchanger inlet. The control law is designed considering the partial differential equation describing the temperature of the internal fluid, and the manipulated control is the boundary condition for the partial differential equation describing the temperature of the jacket fluid. The performances of the controller have been evaluated by simulation and the results show that it provides good regulation and tracking performances. The robustness of the controller has also been studied when velocities of both internal and external fluid, and physical properties of the heat exchanger are subjected to sudden fluctuations. For noisy measurements and for practical implementation, the moving average filtering and Kalman estimation approaches that provide the required state temperatures to be used in the controller are discussed. The control by manipulating the jacket flow rate has also been considered to compare the respective benefits of both strategies

Application of model predictive control to the BSM1 benchmark of wastewater treatment process

International audienceWastewater treatment processes are difficult to be controlled because of their complex and nonlinear behavior. This paper applied model predictive control (MPC) to the Benchmark Simulation Model 1 (BSM1) wastewater treatment process to maintain the effluent quality within regulations-specified limits. Good performance was achieved under steady influent characteristics, especially concerning the nitrogen-related species. In presence of influent disturbances, two approaches have been studied: the addition of a feedforward action based on the measurement of the influent flow rate; the use of nonlinear model predictive controller by addition of a penalty function. The effects of two approaches were visible on the decrease of ammonium and nitrogen concentration which were considered as being of major importance. The results showthat MPC can be effectively used for control inwastewater treatment process. By comparing performances, the nonlinear model predictive control strategy with penalty function demonstrates best with small effluent quality index and acceptable aeration and pumping energy consumption

Dynamisches Verhalten von durchgehenden Reaktionen in Anhäufungen granulierter staubförmiger Stoffe

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Convective heat and mass transfer with evaporation of a falling film in a cavity

The heat and mass transfer involved in the evaporation of a water falling film in a closed rectangular cavity of geometric form factor equal to 10 is studied numerically and experimentally. The wall which supports the liquid film is heated by a constant heat flux. The vapor thus formed is condensed on the opposite wall maintained at a constant and uniform temperature. The study objective is a better understanding of the evaporation phenomenon in order to improve the yield. A numerical model has been built from the conservation equations in the gas and liquid phases. The main characteristic of the present study is the way of treating the transfer in the liquid film. A method based on the mass and heat balances has been developed where the balances are obtained by integration of the mass and energy conservation equations over small height increments. This method allows us to avoid the explicit solution of the momentum and energy equations which is more difficult because of the presence of a fabric material placed on the heated wall to stabilize the liquid film. The obtained results allow us to describe the thermodynamic state of the heated film by means of the liquid temperature and evaporation flow rate. The heated film presents two zones: a heating zone located near the inlet of the cavity and an evaporation zone which covers the rest of the wetted surface. The extent of this effective surface of evaporation has been studied with respect to the operating parameters: on the one hand, the heat flux and the temperature of the condensation wall that in general depend on the climatic conditions, on the other hand, the water feed temperature and flow rate that can be varied by the user and act directly on the liquid film. The influence of the two latter parameters on the exchanges at the liquid–gas interface has been characterized in terms of local Sherwood and Nusselt numbers. 2005 Elsevier SAS. All rights reserved