Session: 03-01 Advanced Combustion Dynamics and Emission Control in Ammonia and Hydrogen Systems

Paper Number: 155047

Laminar Burning Speed Measurements of Ammonia-Hydrogen Mixtures at Elevated Pressures for Gas-Turbine Applications 

Major efforts are underway to identify sustainable engineering solutions to reduce industrial dependence on fossil fuels and minimize climate impacts from carbon-based emissions. Projections from the U.S. Department of Energy’s (DOE) Energy Information Administration (EIA) predict a 36% increase in industrial hydrocarbon consumption through 2050 in their 2023 Annual Energy Outlook report. One solution to address these phenomena is the implementation of hydrogen-based fuels to the industrial fuel sector. Ammonia (NH₃) specifically has been shown to serve as an effective hydrogen (H₂) carrier in both power and transportation applications, as its similar properties to existing fuels like propane (C₃H₈) allow for equipment compatibility in storage and transportation operations. From a power perspective, NH₃ provides zero-carbon combustion while capitalizing on high volumetric energy density and octane numbers- enabling NH₃ to be used as an efficient fuel in high-pressure compression machinery. As a result of these findings, applied turbine-combustion research on NH₃^­ and H₂ fuels has been conducted to identify combustion performance parameters to facilitate the development of high-pressure, sustainable turbomachinery. One key combustion parameter is the laminar burning speed (LBS), which provides turbine design engineers with knowledge of combustion physiochemistry, flashback, and efficiency. While abundant literature exists on the combustion of NH₃ and H₂ fuels at atmospheric pressures, there is not sufficient evidence in elevated-pressure environments to provide a comprehensive understanding of NH_­3 and H­₂ combustion phenomena. To advance the state of the knowledge, NH­₃ and H₂ mixtures were ignited in a spherical chamber across a range of equivalence ratios at 323 K and 10 atm to measure LBS which was determined using constant-pressure and multizone constant-volume methods. The experimental conditions were selected to restrict NH₃ to a gaseous state. Laminar flames were achieved via oxidant dilution and were validated according to Lewis number calculations and Schlieren imaging. The effect(s) of initial pressure and H₂ addition to NH₃ fuel were observed by comparing the LBS of various NH₃-H₂ mixture compositions (0% H₂, 30% H₂, 70% H₂) at varying initial pressures (5 atm - 10 atm). Preliminary results revealed LBS enhancement and lean peak-LBS shifts with H₂ dilution. LBS suppression was observed for elevated pressures across H₂ concentrations. Sensitivity analyses conducted across mixture compositions and initial pressures will reveal chemical-kinetic reactions leading to discrepancy in LBS estimation. The experimental results collected for this investigation will be simulated using the Stagni et al. mechanism, the Otomo et al. mechanism, and the UCF NH₃-H₂ mechanism- which is currently under development. Simulated results will be assessed against experimental LBS and reaction sensitivity data to advise the reduction and optimization of chemical-kinetic mechanisms, ultimately to aid in the design of sustainable, high-pressure turbine systems.

Presenting Author: Louis Yovino UCF

Presenting Author Biography: Louis is a PhD student at UCF

Authors:

Louis Yovino UCF
Ahmed Safdari UCF
Gihun Kim UCF
Ramees Khaleel Rahman UCF
Subith Vasu UCF
Robert Steele EPRI
Mark Winquist GTI Energy
Ganesan Subbaraman GTI Energy
John Vega GTI Energy