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

Abstract

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 NOx, 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 NOx reduction is observed. This decrease in the WI may lead to an increased requirement of the fuel supply pressure.