Adaptive process control of an acetic acid reactor

This paper describes how QuickStudy/sup TM/, a model based adaptive process controller, was used to solve a key control problem associated with an acetic acid reactor. The operating company had achieved greater production rates and efficiency through the use of an improved catalyst but with the penalty of decreased reactor temperature stability. A PID based control strategy became unstable at high unit throughput resulting in reduced production rates and lower sustained throughput. The search for a suitable control solution was complicated by the fact that the reactor temperature was open loop unstable and therefore could not be "bump tested". QuickStudy/sup TM/ was used successfully to improve controllability without disrupting production. Reactor temperature standard deviation was reduced from 3.6 to 0.8 and sustained throughput was increased by over 5%. Investment payback was less than 2 months. QuickStudy has been performing reliably in this application for over 2 years.