Steam–Gas Condensing Turbine System for Power and Heat Generation

This study deals with new internal combustion turbine power systems in which a steam-gas mixture is the working medium. Heat is delivered to the system by injecting gaseous fuel and steam into the combustion chamber. Unlike in STIG systems, the fluid expansion in the turbine is much deeper (much below the atmospheric pressure) and the exhaust gas is cooled in a heat exchanger-condenser in such a manner that a significant amount of water can be recovered. The non-condensing gases (CO2 + N2 + rest of O2) from the exhaust fluid are compressed, after additional cooling, and discharged into the atmosphere.If a cheap or waste fuel is available, the steam to be injected into the combustor can be produced in a waste fuel-burning boiler or in conventional coal boiler. In this case the heat exchanger between the turbine and condenser can deliver significant amounts of useful (process or district) heat or / and preheated feedwater for the boiler.The efficiency analysis of this new energy system shows a growth by more than 10 percent points in comparison with the conventional STIG engine, at the same pressure ratio and turbine inlet temperature.Copyright © 2001 by ASME