Thermodynamic analysis of a gas turbine utilizing ternary CH4/H2/NH3 fuel blends

Abstract

Ammonia and hydrogen have gained significant interest as fuels for power generation as part of a larger strategy to decarbonization the power generation sector. By mixing these carbon-neutral fuels with natural gas, lower carbon dioxide emissions can be achieved in gas turbine operations without any retrofitting. However, no studies have explored methane-hydrogen-ammonia ternary fuel blends on gas turbines performance and emissions. In this work, a 50 MW simple Brayton cycle model was developed, incorporating operating conditions found in commercial power plants and chemical equilibrium to represent realistic exhaust temperatures and species. Over 5150 fuel combinations of ammonia-hydrogen-methane were assessed and performance parameters (i.e., system efficiency and specific fuel consumption) are reported. The optimal system efficiency changes with fuel composition, with most ternary fuel blends achieving highest system efficiency at equivalence ratios between 0.37 and 0.39. Gas turbines operating with high ammonia concentrate fuel blends achieve high system efficiencies (up to ∼44.6%) but result in high specific fuel consumption (up to 0.44 kg.kWh−1). The fuel blend of 78%/22% H2/NH3 was found to be the optimal fuel choice, achieving higher system efficiency with similar fuel consumption as pure methane.