Hydrogen Enriched Combustion Testing of Siemens SGT-400 at High Pressure Conditions

Following successful testing of the SGT-400 combustion system at atmospheric conditions with hydrogen enriched natural gas, a high pressure combustion test campaign was carried out at the Siemens test facility in Lincoln UK. Combustion performance at full engine operating conditions was studied, with the aim of demonstrating the capability of the standard SGT-400 combustion hardware to fire fuels with increased hydrogen content. Measurements consisted of: a pilot tip thermocouple to monitor the risk of flashback; pressure sensors to capture the combustion dynamics signature; and emissions instrumentation measuring NO_x and CO. The combustor was also instrumented with thermocouples to monitor both the distribution of wall temperatures and potential locations of flashback when utilizing the highly reactive hydrogen enriched gas. The current paper reports the findings of the high pressure tests and compares with the atmospheric results that had been documented previously. Combustion behavior at full engine pressure and temperature was found to be consistent with atmospheric conditions. Pilot tip temperature increased with the hydrogen gas content due to the higher flame speed. Combustion dynamics shifted to a higher frequency for the hydrogen enriched gas, and heat release fluctuations increased. NO_x emission also increased with the hydrogen blending due to the enhanced fuel reactivity. The high pressure tests demonstrated that the SGT-400 standard DLE combustion system can operate without risk of flashback for up to 20% vol hydrogen content. The next phase of the hydrogen program is to test a production engine using enriched gas and confirm its full operational characteristics. Extending the operational envelope of the standard DLE combustion system to hydrogen contents above 20% vol is also of interest.