Santee Cooper's Cross Station has implemented a catalyst optimization program that reduces catalyst replacement cost while maximizing catalyst performance. This case study illustrates the economic advantages of taking a holistic approach to optimizing unit catalyst performance by controlling slag, fouling, sulfur trioxide, and ammonium bisulfate-key factors that lead to premature shortening of catalyst life. With catalyst costing $2 million a layer and up, there is plenty of economic motivation to find ways to improve its life.