An Evaluation of Steam Injected Combustion Turbine Systems

Performance and economic evaluation results are presented for steam injected combustion turbine systems. The steam injected gas turbine plant shows a potential for low capital cost and high efficiency for sites where water consumption is not a deterrent. Steam produced in a heat recovery steam generator is injected into the gas turbine combustor section to the extent of 0.155 pounds steam per pound of air flow. Water consumption is estimated to be 2.5 pounds per kWh (1.13 kg/hWh). When burning distillate fuel at 2200°F (1204°C), the potential efficiency is 40 percent as compared to 38 percent for a simple cycle gas turbine, and the specific output per pound of air flow is increased by 30 percent. The estimated capital cost per kilowatt is 3 percent greater than that for the simple cycle gas turbine.