IMPLEMENTATION OF ADVANCED OPERATIONAL AND CONTROL TECHNIQUES FOR A PILOT DISTILLATION COLUMN WITHIN A DCS ENVIRONMENT

A well-instrumented pilot-scale continuous distillation column has bee n interfaced with an industrial distributed control system (DCS-ABB MO D 300) and a VAX cluster through the network. The column separates eth anol and water and the set-up is used to implement different advanced control and operational techniques. An ideal supervisory scheme was pr oposed and accordingly gross error detection, identification and estim ation, data reconciliation, simulation, efficiency modification and op timisation modules were implemented to provide the grounds for advance d operation of chemical processes. it is shown that these techniques p lay a vital role in control and optimisation of a given process. Furth ermore, a novel robust multivariable, low order, high performance, mod el-based controller was designed and implemented as a standard PID blo ck within the DCS. Finally, the answer to an important question of how close to the optimum can an operator operate without fear of violatin g the constraints in the face of disturbances is discussed; this led t o a semi-online optimising control program acting as another informati ve module that completes a unified framework. The paper is accompanied by some experimental evidence which demonstrate the importance of eac h implemented module individually and as a unified set-up. (C) 1998 El sevier Science Ltd. All rights reserved.