Early Stage Process Controllability Assessment

Abstract

Publisher Summary This chapter discusses the controllability of process design for designing a plant. Traditionally, process design has concentrated on the design of a plant intended to operate at a set of well defined flow-sheet conditions. This has tended to result in the problem of how to achieve and maintain these flow-sheet conditions being postponed to the later stages in the design process· This sequential approach to system design can result in plants which are difficult to control. Often, remedial work has to be done, post start-up, for the plant to achieve its control objectives. In extreme cases, the plant dynamics have been so difficult that plant redesign has had to be done to enable it to run successfully. The pressures to reduce capital cost and plant inventories together with the need for flexible operation mean that this approach are no longer acceptable. To enable early consideration of control the process, engineer requires a set of simple control indicators which are easily understood by non control engineering specialists.