Robust process control at Cerestar's refineries

With annual sales of over $2 billion, Cerestar is Europe's leading manufacturer of made-to-order wheat- and corn-based starch products. Cerestar relies on refineries that are highly automated and require large fixed investments. Starting in 1993, we developed Robust Process Control (RPC) to increase average throughput and reduce throughput variation by combining engineering principles with OR/MS techniques. RPC includes a mathematical-programming model to reduce downtimes due to product switchovers, models for process optimization, and dynamic control models for process-flow synchronization. Cerestar implemented the resulting decision support system at eight refineries in six countries. It has increased average daily throughputs by 20 percent and reduced average throughput variation by 50 percent. Concomitantly, the refineries have reduced their consumption of supplies and utilities. In addition to over $11 million in annual benefits, RPC has had major strategic and organizational impact.