Combustion Turbine Fuel Flexibility From Plant Designer’s Perspective

Industrial combustion turbines offer plant owners the flexibility of generating power typically either from natural gas or distillate oil # 2. This paper, from the power plant designer’s perspective, expands upon fuel variability and flexibility in combustion turbines based on the author’s past project experience. For various alternate fuels, issues such as additional fuel treatment requirements, fuel system design, ignition reliability, flame stability, emissions, impact on parts life and impact on power output are discussed. Initially, a generic combustion envelope is defined for gaseous fuels largely based on turbine manufacturers’ requirements. Then specific project experience addressing the fuel treatment systems and gas turbine modifications are presented for the following fuels: a) Medium Btu well-head gas, b) Vaporized LPG-natural gas mixture, c) Landfill gas, d) Syngas from gasification. Similarly, a generic combustion envelope is defined for liquid fuels and the specific requirements to burn the following alternate liquid fuels are discussed: a) Crude oil, b) Naphtha, c) Bio-diesel. Finally, due to its “green energy” potential, feasibility of burning coal bed methane (CBM) and coal mine ventilation air methane (VAM) in gas turbines is investigated.