Extension of Fuel Flexibility in the Siemens Dry Low Emissions SGT-300-1S to Cover a Wobbe Index Range of 15 to 49 MJ/Sm³

The extension of gas fuel flexibility in the Siemens SGT-300 single shaft (SGT-300-1S) is reported. A successful development program has increased the capability of the Siemens Industrial Turbomachinery, Lincoln (SITL) dry low emissions (DLE) burner configuration to a fuel range covering a Wobbe index (WI) from 15 to 49 MJ/Sm³. The WI reported in this paper is at a 15 °C fuel temperature. The standard SGT-300-1S SITL DLE combustion hardware allows for gas and liquid fuels within a specified range typically associated with natural gas and diesel, respectively. The range of the WI associated with natural gas is 37–49 MJ/Sm³. Field operation of the standard production SGT-300-1S has confirmed the reliable operation with an extension to the fuels range to include processed landfill gas (PLG) from 30 to 49 MJ/Sm³. The further extension of the fuel range for the SGT-300-1S SITL DLE combustion system was achieved through high pressure testing of a single combustion system at engine operating conditions and representative fuels. The variations in the fuel heating value were achieved by blending natural gas with diluent CO₂ and/or N₂. Various diagnostics were used to assess the performance of the combustion system, including the measurement of combustion dynamics, temperature, fuel supply pressure, and the emissions of NO_x, CO, and unburned hydrocarbons (UHCs). The results of the testing showed that the standard production burner can operate for a fuel with a WI as low as 23 MJ/Sm³, which corresponds to 35% CO₂ (by volume) in the fuel. This range can be extended to 15 MJ/Sm³ (54.5% CO₂ in the fuel) with only minor modification to control losses through the burner and to maintain similar fuel injection characteristics. The SITL DLE combustion system is able to cover a WI range of 15 to 49 MJ/Sm³ in two configurations. The results of testing showed a lowering in the WI, by diluting with CO₂ and/or N₂, so that a benefit in the NO_x reduction is observed. This decrease in the WI may lead to an increased requirement of the fuel supply pressure.