Exploration of Exhaust Gas Recirculation for Improved Carbon Capture System Performance on a 3.5 MWe Liquid-Fueled Gas Turbine

Abstract As a part of its Climate Action 2030 plan, the US Navy has set ambitious carbon emission reduction goals that require the decarbonization of its vessel’s propulsion systems. Liquid-fueled gas turbines are the core of power generation for propulsion and auxiliary systems for much of the Navy’s fleet, due to their propensity for mission readiness, unlike modern alternative fuel systems. It is for this reason that the Navy has begun pursuing onboard carbon capture and storage strategies that would ordinarily be size-prohibitive, if not paired with high-fraction exhaust gas recirculation (EGR) systems. As a start, this work discusses the design and deployment implications of an EGR system on a 3.5 MWe Solar Turbines Centaur 40 gas turbine at Colorado State University (CSU). System requirements and design considerations of a gas turbine EGR system are presented, along with detailed analysis of (1) a proposed EGR/intake air mixer and (2) a reduced-cost bottled gas manifold that will serve as a surrogate of an EGR system. The envisioned EGR system and lab-based surrogate gas manifold were designed and evaluated using a 0D and 3D software (Flownex & Converge CFD software). Simulation results informed component sizing, the estimated power consumption, and analysis of mixer performance for both an actual EGR and surrogate EGR system. Results of the system simulations indicate a heat load demand of nearly 8MW to cool the EGR and power an EGR diversion fan. The total pressure drop of the actual EGR system was 531.97 Pa, and the surrogate system pressure drop was 916.13 Pa. Results of the mixer performance analysis indicated the shape and size of EGR injection ducts greatly influenced the mixing results. On mixing effectiveness, the quantity, size, and placement of EGR injectors had the most significant impact, while geometric adjustments were found to have minimal impact. Further, interaction of multiple EGR flow streams inside of the duct shows promising results to a non-intrusive mixing system. Successful EGR implementation will allow for the retrofitting of existing systems to improve carbon capture and storage (CCS) system performance and lower emissions. Future work will encompass full scale EGR testing on the recently installed CSU Centaur 40 gas turbine.