Co-Firing Hydrogen With Natural Gas for 9 MW Siemens Energy Dry Low Emissions Combustor: Part I – High Pressure Rig Test

Abstract To accelerate decarbonisation efforts in the industrial gas turbine applications, Siemens Energy’s industrial gas turbine engines, ranging from 5 MW to 15 MW, are now capable of operating on a fuel blend containing at least 30% hydrogen (H2) by volume and natural gas (NG). To validate this 30% H2 capability for the 9 MW SGT-300-2S engine, high-pressure rig testing was conducted at the Siemens Energy Clean Energy Center (CEC) in Berlin. The Dry Low Emissions (DLE) combustor was initially operated with natural gas to establish a baseline. Subsequently, it was fuelled with a 30% H2 blend under various ambient temperature conditions, including ISO, −20 °C, and +45 °C. To evaluate operational margins, tests were extended to 35% and 40% H2 concentrations under ISO conditions. Finally, the combustion system’s robustness was rigorously tested under a wide range of overfiring conditions, including over-fuelling at constant load and elevated load. This Part I paper presents the high-pressure rig test results. Numerical simulations to gain deeper insights into the physics are reported in Part II. The impact of H2 content in the fuel on combustor performance was investigated, focusing on factors such as burner metal temperature, NOx and CO emissions, combustion dynamics, and combustor wall temperatures. Test results indicate that burner metal temperatures and NOx emissions increase with increasing H2 content in the fuel. The turbine entry temperature (TET) at which CO emissions begin to rise is lowered with increasing H2 content. This suggests that adding H2 to the fuel can lower the emissions turndown temperature for controlling CO emissions, thereby improving the engine’s part load thermal efficiency. Combustion dynamic pressure amplitudes remained low for H2 concentrations up to 40% by volume. Combustor wall temperature profiles for H2 operation up to 40% were comparable to those for natural gas operation. Test results demonstrate that the combustion system can safely operate with up to 40% H2 in the fuel without flashback or hardware damage. The effect of pilot split on combustion performance was also investigated for natural gas and the fuel blends with 30% and 40% H2. A key finding in this paper is that different fuel compositions may require different pilot split and turndown control temperature for optimal operation.