Application of Advanced Process Control techniques for a cement rotary kiln

In this work, the control optimization of a rotary kiln located in a cement plant is described. The need to enhance the efficiency level, to increase the profitability as well as the commitment to meet precise production standards has motivated the adoption of Model Predictive Control techniques. The adopted system architecture is composed of two different optimization layers. A suitable interaction policy has been developed so as to improve control performances and to meet possibly variable economic goals. The advantages of the proposed architecture are shown by significant simulations. The developed predictive control system has been implemented on real plant and its overall performances are compared to the performances of the previous standard PID control system. Very satisfactory system performances have been achieved been able to attain both economic benefits and minimization of environmental noxious emissions.

I. Introduction

Cement production is characterized by complex chemical and physical processes. Very high temperatures are required to cause chemical reactions that convert its primary element, the limestone, suitably blended with other materials, like clay, into cement. Since in the cement market product differentiation is very small, firms have to invest in process innovation and advanced control technologies in order to increase profitability and survive in this industry.