FORT SASKATCHEWAN PLANT IS RETROFITTED WITH AUTOMATION.

The plant consists chiefly of a two-tower distillation train to separate the feed into propane, butane, and pentanes plus. The plant has two unique features that make control difficult. First, each batch of feed has a different composition. Batches come into the plant on the average of once per day. The second unique feature is that all fuel for the plant is purchased. It is subject to rapid price escalation. In order to make the minimum possible changes in the method of plant operation, and to allow the operators a routine control method to return to in case of a computer failure, supervisory control was selected. The computer controls the set point on a board mounted controller which in turn controls the valve. This system was installed for slightly over 500,000. Fuel gas reductions achieved as a result of the system were better than those originally estimated. Product compositions have been much more evenly controlled even through condensate bounces.