Experimental investigation of SO2 poisoning in a Molten Carbonate Fuel Cell operating in CCS configuration

One of the most interesting innovations in the CCS (Carbon Capture and Storage) field is the use of MCFCs as carbon dioxide concentrators, feeding their cathode side (or air side) with the exhaust gas of a traditional power plant. The feasibility of this kind of application depends on the resistance of the MCFC to air-side contaminants, with particular attention to SO2. The aim of this work is to investigate the effects of poisoning when sulphur dioxide is added to the cathodic stream in various concentrations and in different operating conditions. This study was carried out operating single cells (80 cm(2)) with a cathodic feeding composition simulating typical flue gas conditions, i.e. N-2, H2O, O-2 and CO2 in 73:9:12:6 mol ratio as reference mixture. On the anodic side a base composition was chosen with H-2, CO2 and H2O in 64:16:20 mol ratio. Starting from these reference mixtures, the effect of single species on cell poisoning was experimentally investigated considering, as main parameters chosen for the sensitivity analysis, SO2 (0-24 ppm) and CO2 (4-12%) content in the cathodic feeding mixture, H-2 (40-64%) content in the anodic stream as well as the operating temperature (620-680 degrees C). Results showed that degradation caused by SO2 poisoning is strongly affected by the operating conditions. Data gathered during this experimental campaign will be used in a future work to model the poisoning mechanisms through the definition of MCFC electrochemical kinetics which take into account the SO2 effects. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.