Hybrid fuel cell—Supercritical CO₂ brayton cycle for CO₂ sequestration-ready combined heat and power

The low prices and its relatively low carbon intensity of natural gas have encouraged the coal replacement with natural gas power generation. Such a replacement reduces greenhouse gases and other emissions. To address the significant energy penalty of carbon dioxide (CO₂) sequestration in gas turbine systems, a novel high efficiency concept is proposed and analyzed, which integrates a flame-assisted fuel cell (FFC) with a supercritical CO₂ (sCO₂) Brayton cycle air separation. The air separation enables the exhaust from the system to be CO₂ sequestration-ready. The FFC provides the heat required for the sCO₂ cycle. Heat rejected from the sCO₂ cycle provides the heat required for adsorption-desorption pumping to isolate oxygen via air separation. The maximum electrical efficiency of the FFC sCO₂ turbine hybrid (FFCTH) without being CO₂ sequestration-ready is 60%, with the maximum penalty being 0.68% at a fuel-rich equivalence ratio (Φ) of 2.8, where Φ is proportional to fuel-air ratio. This electrical efficiency is higher than the standard sCO₂ cycle by 6.85%. The maximum power-to-heat ratio of the sequestration-ready FFCTH is 233 at a Φ = 2.8. Even after including the air separation penalty, the electrical efficiency is higher than in previous studies.