Computer Optimization of Steam Production

Abstract

As fuel costs continued to rise sharply during the 1970' s, the staff at Exxon's Benicia Refinery realized there was a growing economic incentive to optimize the production of high pressure steam. A significant percentage of the Refinery's total energy is consumed in generating high pressure steam. Recently, a computer program was implemented to optimize high pressure steam production.

The first challenge in developing the program was to provide reliable analog and digital instrumentation allowing simultaneous analog header control along with effective digital steam flow control. Once appropriate instrumentation became available, the effort focused on identifying the best approach for developing the computer control program. After screening several alternatives, it became apparent that we were dealing with an allocation problem which could be effectively handled with a linear program. The control program has performed well since it was commissioned. It has experienced a service factor of greater than 95% while reducing energy consumption of the boilers by over 500 million Btu's per day.