Thermodynamic analysis of a novel hybrid gas turbine – solid oxide fuel cell power generation system using ammonia as a zero-carbon fuel

Abstract

Ammonia has emerged as a promising hydrogen carrier and carbon-free fuel. This study designs a novel gas turbine-solid oxide fuel cell (GT-SOFC) hybrid energy system, distinct from traditional SOFC-GT configurations, utilising ammonia as the primary fuel. In this hybrid system, ammonia is combusted with oxygen under fuel-rich conditions in the GT, generating both electricity and hydrogen. Hydrogen is then fed into the SOFC for electricity generation. The GT-SOFC hybrid system was designed and modelled using Aspen Plus. The first and second laws of thermodynamics were applied to perform energy and exergy analyses of the proposed system. A parametric study was conducted to study the effect of key parameters on the performance of the hybrid system, including equivalence ratio, combustor pressure, current density in the SOFC, and fuel utilisation ratio. The fuel utilisation ratio in SOFC was found to have a significant impact on the performance of the GT-SOFC hybrid system. The NOx emissions from this hybrid system were found to be negligible. An energy and exergy efficiencies of 75.5% and 72.1%, respectively, were achieved, which were higher compared with the conventional SOFC-GT system with a similar power output.