HANDLING PROCESS DISTURBANCES AND MEASUREMENT ERRORS

In a continuous chemical process the accuracy and reliability of proce ss and analytical measurements are often a critical factor in control system performance and ultimately in product uniformity. This paper fo cuses on our experiences in the area of continuous process improvement and product variability reduction. It explores some of the present se nsor deficiencies and their effect on feedback control systems. It dis cusses intermittent and cyclic disturbances and sensor errors, as well as some intelligent methods for validation. Finally, it discusses som e statistical analysis tools for assisting in the detection of ''speci al causes'' and prerequisites to consider when applying advisory and s upervisory control strategies.