Expanding Fuel Flexibility Capability in GE’s Aeroderivative Engines

Abstract

GE Aviation, through its network of gas turbine OEM’s, has received an increasing number of inquiries and request for quotes for the use of non-standard gas fuels in aero-derivative gas turbine applications. Factors influencing this trend include: increased development of LNG production facilities, increased availability of bio-fuels, lack of availability of standard fuels, reduced acceptance of flaring process gases, and more stringent policies on exhaust emissions. These inquiries and requests propose the use of gas fuels with higher levels of C2+ constituents, or concentrations of hydrogen greater than 5%, or fuels with ever increasing concentrations of high inert gases. Responding to this interest, GE has launched several programs to expand the capability of both SAC (Single Annular Combustor) and Dry Low Emission (DLE) combustion systems. Recent SAC fuel system design enhancements have enabled the LM2500 gas turbine family to operate with either of two, high hydrogen content gases: COG (Coke Oven Gas), a medium BTU fuel (25–35 MWI (Modified Wobbe Index)); or with SYNGAS, a bio-derived, low BTU fuel, (12–14 MWI). To support expanding the DLE capabilities, a series of combustion rig tests and full-scale engine tests have been conducted. Combustion rig testing at one of GE’s Global Research Centers (GRC) has focused on non-standard gas fuels with high concentrations of C2+ constituents. The higher flame speeds of these fuels increase the potential for flashback, and the resulting potential for premature combustor and/or fuel nozzle distress. These tests have allowed GE to more than double the allowable amount of C2+ concentrations in fuel. An LM2500Plus DLE engine recently completed a series of high inert gas fuel testing designed to assess combustor operability and exhaust emissions. This paper intends to summarize the advances GE has made in expanding the range of gas fuels that can be accommodated in the LM2500 and LM6000 product lines.