(14c) Maintaining Ac&O Applications, Sustaining the Gain

From 1999 till 2004, the Dow Chemical Company carried out a large program that resulted in the implementation of Advanced Control and online Optimization (AC&O) in all our Ethylene plants. This program required a concentrated effort and yielded significant benefits. But this is not a one-off achievement?been there, done that. Those AC&O applications require continued support in order to sustain those benefits.

After the impetus and enthusiasm of the project phase wanes, new impetus and enthusiasm must be found to overcome some significant obstacles to continued AC&O productivity. (We fell in love, we got married, now we only have to make this marriage work?to the best of our abilities.) This paper reviews the main challenges we face in maintaining the previously attained AC&O gains. It will also explain the support systems implemented and further solutions being developed.

In the first place, we will review our AC&O support organization, as well as the impact on that organization due to personnel turnover or limited availability. Technical challenges caused by rapid software and platform upgrades will also be examined. Further, our plants?the physical processes we are trying to control and optimize?keep changing every few years. Our proposal to best deal with this situation will be described, and also the practical difficulties we are encountering in its implementation. We will close by reviewing the final outcome of all these efforts: application performance and benefits and their variation with time.