Application of MCFCs for active CO2 capture within natural gas combined cycles.

Abstract: This paper presents an analysis of the application of Molten Carbonate Fuel Cells (MCFC) in a natural gas fired combined cycle power plant to capture CO₂ from the exhaust of the gas turbine. The gas turbine flue gases are used as cathode feeding for a MCFC, where CO₂ is transferred from the cathode to anode side, concentrating the CO₂ in the anode exhaust. This stream is then sent to a CO₂ removal section consisting either in (i) an oxygen combustion of residual fuel compounds, or (ii) a cryogenic CO₂ removal section, cooling the exhaust stream in the heat recovery steam generator. The MCFC is based on Ansaldo Fuel Cells experience, fed with natural gas processed by an external reformer which is thermally integrated within the FC module. Differently from more conventional approaches to CO₂ capture, it works increasing the plant power output, acting as an active CO₂ concentrator. The plant shows the potential to achieve a CO₂ avoided ranging between 58 and 68%, depending on the configuration while taking advantage from the introduction of the fuel cell, the final electric efficiency is lower from 0.2 to 0.8 points lower than the original combined cycle (57.8% LHV in the most efficient configuration). The power output increases by about 22%, giving a potentially relevant advantage with respect to competitive carbon capture technologies. [Copyright &y& Elsevier]