Carbon capture with molten carbonate fuel cells: Experimental tests and fuel cell performance assessment

Molten carbonate fuel cells (MCFCs) may operate as CO2 separators and concentrators while generating electric power, being thus a very interesting candidate to be used as carbon capture systems in fossil fired power plants.The main aim of this work is to understand the MCFC performance, its potential and efficiency to separate CO2 from the exhaust gas of fossil fired power plants and the effect of critical parameters such as the cathodic carbon dioxide concentration (XCO2XCO2) and utilization (UCO2UCO2), as well as the partial pressure ratio between oxygen and carbon dioxide (PO2/PCO2PO2/PCO2) and other parameters such as the oxygen concentration (XO2XO2), utilization (UO2UO2) and the total cathodic flow rate (Qcat). This was achieved by studying the experimental behaviour of a single MCFC when it is fed with a mixture simulating the composition of the exhaust gases of a combined heat and power plant, in order to point out potential limitations in the fuel cell operating conditions.In particular, the carbon dioxide concentration in the cathodic section was shown to be a critical factor at low values, that can both induce quick voltage drops and make the cell sensitive to the other parameters, which are otherwise not so important.

► A molten carbonate single cell used as a carbon dioxide concentrator for carbon capture was studied.
► MCFCs for carbon capture allow to capture CO2 and produce power at the same time.
► A single fuel cell was tested to show the optimal operating conditions and limitations.
► The lower CO2 concentration at which performance decreases was shown.
► The MCFC is a feasible technology for carbon capture in small medium fossil fired power plants.