Understanding the Potential and the Challenges of a NGCC Integrated With Hydrogen-Assisted EGR and CO₂ Capture

CO₂ capture plays an important role in the energy transition. As the integration of CO₂ capture on a gas turbine energy system induces an efficiency penalty, there has been growing interest in the development of combustion systems integrated with CO₂ capture with improved efficiency and operability. This study investigates the potential and the challenges of a NGCC integrated with H₂-assisted EGR and CO₂ capture. A fit-for-purpose model of a GT, along with an in-house tool to model the CO₂ capture process, were employed to capture the key effects of EGR. The results show that the CO₂ capture energy requirement and equipment sizes consistently decrease at increasing EGR rates, with the conclusion that the EGR level should be as high as possible. On the other hand, a higher EGR rate determines a decrease of the O₂ concentration to the combustor, with problems with combustion stability. The addition of H₂ piloting to stabilize the flame allows achieving otherwise unfeasible EGR rates with an overall positive impact on the system energy efficiency. The main energy consumption of the integrated system is associated with the CO₂ capture, underscoring the importance of EGR in reducing it. The additional energy penalties of the overall system are minor. As the energy consumption and efficiency are proxies for operating costs, and the equipment sizes are proxies for capital costs, this study represents a basis for further economic evaluations.