Impact of Ethane, Propane, and Diluent Content in Natural Gas on the Performance of a Commercial Microturbine Generator

The impact of fuel composition on performance of power generation devices is gaining interest as a desire to diversify fuel supplies increases. In the present study measurements of combustion performance were conducted on a commercial natural gas fired 60-kW gas turbine as a function of fuel composition. A statistically designed experiment was carried out and exhaust emissions were obtained for significant amounts of ethane and propane. In addition, a limited study of the effect of inerts was examined. The results show that emissions of NOx, CO, and NOx/NO are not well correlated with common descriptions of the fuel such as higher heating value or methane number. The results and trends indicate that the presence of higher hydrocarbons in the fuel leads to appreciably higher NOx emissions for both test devices operating under similar lean conditions, while having less impact on CO emissions.