A FlameSheet™ Combustion System With Cracked Ammonia As a Fuel

Abstract This work explores design modifications taken to enable a FlameSheet™ combustion system to utilize a mixture of 75%vol H2 and 25%vol N2 as a fuel, simulating (completely) cracked Ammonia (NH3). Rig testing results are given and analyzed. Hydrogen-fired combustion turbines will play a critical role in the decarbonization of the energy sector as renewable energy sources achieve increased market penetration. The scarcity of Hydrogen at large quantities in today’s market demands fuel flexible combustion technology in order to be futureproof. Retrofittable technology to reduce carbon emissions from existing gas turbine power plants are desirable to aid with the transition and enable cost-effective interim solutions for an eventual net-zero carbon economy. Due to the low energy density of gaseous Hydrogen (GH2), and the energy expensive needs to produce, liquify and maintain Hydrogen in liquid form (LH2), liquid Ammonia (NH3) is becoming an attractive Hydrogen carrier for transporting vast quantities of Hydrogen across great distances. Direct combustion of Ammonia has its own challenges, namely the production of huge levels of NOx from the fuel-bound Nitrogen. Equipment may be co-located at a GT site to split NH3 into elemental H2 and N2, in essence eliminating the fuel-bound Nitrogen issue. Additional equipment to obtain a pure Hydrogen stream can be eliminated if cracked NH3 may be directly used safely in a gas turbine. The needed volumetric flow of the gas mixture is far greater than that of pure Hydrogen which presents additional design challenges that will be discussed. A novel combustor was designed and recent high pressure rig testing results are highlighted in this paper to showcase the fuel flexibility of the FlameSheet™ combustion system and its ability to operate with any blend of Natural Gas and cracked Ammonia. Differences in flame stability, emissions, and combustion dynamics trends will be compared between Natural Gas and cracked Ammonia operation. Considerations are also given to various engine operating concepts.