Fuel flexibility of micro gas turbines

Abstract

Most micro gas turbines (MGTs) are currently operated with natural gas and biogas. However, MGTs are generally able to operate on a variety of different gaseous and liquid fuels, including natural gas, biogas, syngas, gasoline, kerosene, and diesel fuel/distillate heating oil. Compared to piston engines micro gas turbines can oxidize fuels with very low heating value without engine derating. The combustion systems of micro gas turbines can also be designed in a way that fuels with lower Methane Number as well as gases with heavier hydrocarbon components can be easily burned. The same is true for fuels containing hydrogen. The presentation focusses on the MGT combustor research & development within the German Aerospace Center in terms of fuel flexibility. The developed combustion systems are based on the FLOX® (flameless oxidation) concept. Latest results include the operation with wood gas (coupling of wood gasifier and MGT) and volatile organic compounds (VOCs). Also, combustion systems with high operation flexibility able to oxidize SOFC off gas and natural gas (hybrid power plant: coupling of SOFC and MGT) or biogas and natural gas using the same design are presented. The development of the combustion systems is based on computational fluid dynamics simulations using detailed chemistry for modelling the combustion process. Before implemented into the MGT they are extensively characterized in a combustor test rig under atmospheric conditions with combustor inlet temperatures corresponding to the real boundary conditions in the MGTs.