Effects of Fuel Composition on Flammability Limit of a Lean Premixed Combustor

Abstract

Fuel flexibility is desired in advanced power generating gas turbines operating in the lean premixed combustion mode. In this study, experiments were performed in a lean premixed, swirl-stabilized combustor operated at atmospheric pressure to quantify how adding liquid petroleum gas (LPG), hydrogen, oxygen, nitrogen, and carbon dioxide to natural gas (NG) affected the flame stability. The flame extinction characteristics were obtained for NG fuel mixtures with up to 40% by volume of the indicated gases. The combustion air was supplied at room temperature and the fuel-air mixture was fully premixed before reaching the combustor. The total fuel-air flow rate was varied by a factor of two to achieve a range of aerodynamic conditions. Results demonstrate that additions of hydrogen and oxygen to NG extended the stable operating range of the combustor. Addition of LPG to NG had a slightly adverse effect while the non-reactive species in the NG did not affect the lean flammability limit.