The lower prices and wider availability of natural gas make it important that chemical engineers become familiar with natural-gas processing and applications. One important use is the generation of power by burning natural gas in a combustion turbine. Traditional systems use air for the oxygen source, but the use of high-purity oxygen with stack gas recirculation is an alternative when sequestration of carbon dioxide is desired. The limiting design parameter in a combustion-turbine system is a maximum turbine inlet (combustor) temperature because of metallurgical constraints. In air-fired systems, enough air must be used to keep below this limit. In oxygen-fired systems, enough CO2-rich stack gas must be recycled to keep below this limit. The purpose of this paper is to review the chemical engineering process design principles involved in setting up combustion-turbine systems.