Dynamic limit based model predictive control of a flash drying unit

Abstract

A model predictive controller was implemented at the flash drying unit of the Anglo American Platinum Polokwane smelter. The controller uses a mix of standard model predictive control technology and dynamic control limits (based on the rate of change of the hot gas generator average bed temperature) to improve temperature stability across the unit. The improved temperature control resulted in the ability to process 1.80% more concentrate through the unit without the need to increase coal feed, as well as reducing the number of coal feeder trips that result from high temperature events.