Poly-generating closed cathode fuel cell with carbon capture

High temperature fuel cells are a promising technology for ultra-low emission power generation. This paper presents a novel poly-generating system capable of greater than 80% (LHV CH4) co-production efficiency with carbon capture and liquefaction. The proposed system synergistically integrates an air separation unit providing pure oxygen to a fuel cell and liquid nitrogen to a hydrogen separation unit. Both solid oxide and molten carbonate fuel cells may be capable of this integration with additional refrigeration load needed for the molten carbonate system to condense and recirculate carbon dioxide into the cathode stream. Stack temperature control utilizes the endothermic cooling effect of internal fuel reforming. The primary characteristic of the system, converting fuel cell waste heat to produce a secondary fuel (e.g. hydrogen), portends the ultra-high efficiency while enabling additional system design and integration synergies that may reduce complexity, cost, and load following constraints. A unique controller is developed for power and thermal management of a fuel-cooled fuel cell with anode recirculation. A brief economic analysis identifies the potential revenue from each of the four product streams, electricity, hydrogen, heat, and liquid CO2, and presents a conservative, yet favorable assessment of system costs relative to market electricity and hydrogen fuel prices.