Oxidation performance of high temperature materials under oxyfuel conditions

Oxyfuel combustion is widely seen as a major option to facilitate carbon capture and storage (CCS) from future boiler plants utilizing clean coal technologies. Oxyfuel combustion can be expected to differ from combustion in air by e.g. modified distribution of fireside temperatures, much reduced NOx but increased levels of fireside CO2, SO2 and water levels due to extensive flue gas recirculation. Modified flue gas chemistry results in higher gas emissivity that can increase the thermal stresses at the heat transfer surfaces of waterwalls and superheaters. In addition, increased flue gas recirculation can increase the concentration of a number of contaminants in the deposited ash and promote fouling and corrosion. There is relatively little experimental information available about the effects of oxyfuel combustion on the performance of boiler materials. In this work, the oxidation performance of steels X20CrMoV11-1 and TP347HFG has been determined at 580°C/650ºC under simulated oxyfuel firing conditions. The results are presented and compared to corresponding results from simulated air firing conditions.