Integrating ammonia cracking with gas turbine combined cycle for enhanced hydrogen utilization and reduced CO2 emissions

The interest in hydrogen as a measure to replace fossil fuels is growing. Nevertheless, hydrogen poses challenges in storage and transportation because of its high cost and energy loss. The present research addresses this by focusing on transporting ammonia and decomposing it into hydrogen. This study proposes a novel system integrating a gas turbine combined cycle (GTCC) with an ammonia cracking process. This integration involves using ammonia to cool the gas turbine combustor while recovering the necessary heat for cracking, allowing for a hydrogen co-firing ratio of approximately 24.5 %. The system had the highest efficiency and the lowest CO2 emissions compared to other integrated systems. When compared to the GTCC fired with natural gas, the proposed system resulted in a reduction of output by 0.52 %, while the amount of CO2 emitted decreased by 7.28 %, and the efficiency of the system showed a similar level. The system also offers flexible GTCC operation through proposed part-load curves. The proposed method can be applied without sensible modifications if a separate pathway for combustor cooling is available, enabling hydrogen co-firing while simultaneously improving system efficiency and reducing CO2 emissions across a wide range of load conditions.