Steam Utility Systems Are Not "Business as Usual" for Chemical Process Simulators

The operating costs of a typical refinery utility system are so significant that small operational improvements can result in large annual savings. This paper introduces a new utility modelling package designed for PETRONAS to allow in-house modelling and optimization of their refinery and processing plant utility systems. Using this package, engineers can construct a rigorous utility system model which can calculate the actual cost of their utility system, and quantify how operational changes can reduce the bottom line. This paper also contrasts the fundamental differences in approach between utility systems and a steady-state chemical process simulator and provides methods to resolve these differences.