Statistical process control of continuous chemical processes

The increasing demands for improvements in product quality and productivity of chemical processes has led to a heightened interest in the application of statistical process control (SPC) techniques in process industries. It was shown, in many cases, that the existence of conventional process control loops, based upon empirical considerations, was not enough to improve/maintain the quality of the product, especially in the face of process variability. The presence, however, of many input and output process variables, which may be directly or indirectly related to the quality variables, is a major problem encountered in the application of traditional SPC charting methods in chemical processes. Other problems include `one-at-a-time´ or sequential data and autocorrelated data. The paper describes a procedure for developing an effective on-line SPC strategy for continuous chemical processes, considering the problems mentioned above