MODELLING OF A CLINKER ROTARY KILN USING OPERATING FUNCTIONS CONCEPT Kyarash Shahriari 1 * ,† and Stanislaw Tarasiewicz 2‡ 1. Centre de Recherche Industrielle du Qu´ ebec (CRIQ), Quebec City, QC, Canada 2. Laboratory of Complex Automation and Mechatronics, Mechanical Engineering Department, Laval University, Quebec City, QC, Canada Modelling and parameter identification of complex dynamic systems/processes is one of the main challenging problems in control engineering. An example of such a process is clinker rotary kiln (CRK) in cement industry. In the prevailing models independently of which structure is used to describe the kiln’s dynamics and the identification algorithm, parameters are assumed to be centralised and constant while the CRK is well known as a distributed parameter system with a strongly varying dynamic through time. In this work, the kiln’s dynamic is described in the form of a state-space representation with three state variables using a system of partial differential equations (PDE). The structure is chosen so that it can easily be embedded in classical state-space control algorithms. The parameters of the PDE system are called operating functions since their numerical values vary with respect to different operating conditions of the kiln, to their position in the kiln, and through time. A phenomenological approach is also proposed in this paper to identify the operating functions for a given steady-state operation of the kiln. The model is then used to perform a semi-dynamic simulation of the process through manipulating main process variables. La mod´ elisation et l’identification des param` etres de syst` emes/proc´ ed´ es dynamiques complexes constituent l’un des principaux probl` emes en g´ enie des contrˆ oles automatiques. Un exemple d’un tel proc´ ed´ e est le four rotatif clinker dans l’industrie du ciment. Dans les mod` eles actuels ind´ ependamment de la structure utilis´ ee pour d´ ecrire la dynamique du four et l’algorithme d’identification, on pr´ esume que les param` etres sont centralis´ es et constants, alors que le FRC est bien connu comme syst` eme de param` etres distribu´ e avec une dynamique qui varie beaucoup avec le temps. Dans ce travail, la dynamique du four est d´ ecrite sous forme de repr´ esentation d’espace d’´ etats avec trois variables d’´ etats faisant usage d’un syst` eme d’´ equations diff´ erentielles partielles. La structure est choisie pour ˆ etre facilement int´ egr´ ee en algorithmes de commande d’espace d’´ etats traditionnels. Les param` etres du syst` eme d’ ´ EDP sont nomm´ es fonctions d’op´ eration, puisque leurs valeurs num´ eriques varient concernant les diff´ erentes conditions de fonctionnement du four, leur position dans le four et dans le temps. Une approche ph´ enom´ enologique est ´ egalement propos´ ee dans le pr´ esent document pour d´ eterminer les fonctions d’op´ eration pour un fonctionnement en ´ etat stationnaire donn´ e du four. Le mod` ele est ensuite utilis´ e pour r´ ealiser une simulation semi-dynamique du proc´ ed´ e par la manipulation des principales variables du proc´ ed´ e. Keywords: phenomenological modelling, systems identification, cement industry, clinker rotary kiln, operating function INTRODUCTION I n a cement production plant, clinker rotary kiln (CRK) is the most important element of the manufacturing chain whose capacity generally determines the overall capacity of the plant. It is also highly energy-consuming and greenhouse-gas- emitting. Rough estimations show that the cement industry is currently the responsible of 5–7% CO 2 emission and that this volume will reach up to 25% by the year 2050 considering the current trend of increasing demand for cement and the avail- able production technology (Portland Cement Association—PCA, https://www.cement.org; Cement Association of Canada—CAC, https://www.cement.ca). Consequently, improving the efficiency of the CRK and reducing CO 2 emission are among the main concerns in cement manufacturing technology. The latter is also strongly supported by World Business Council for Sustain- able Development under the theme of CO 2 emission reduction and responsible use of fuel and raw materials (World Business † R&D Researcher. ‡ Head of the Laboratory of Complex Automation and Mechatronics. ∗ Author to whom correspondence may be addressed. E-mail address: kyarash.shahriari@ieee.org Can. J. Chem. Eng. 89:345–359, 2011 © 2010 Canadian Society for Chemical Engineering DOI 10.1002/cjce.20398 Published online 9 November 2010 in Wiley Online Library (wileyonlinelibrary.com). | VOLUME 89, APRIL 2011 | | THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING | 345 |