Performance of a low-cost iron ore as an oxygen carrier for Chemical Looping Combustion of gaseous fuels

摘要

This work evaluates the performance of an iron ore, mainly composed of Fe2O3, as an oxygen carrier (OC) for chemical looping combustion (CLC) with gaseous fuels. The OC was characterized by TGA and evaluated in a continuous 500 Wth CLC unit, using CH4, syngas and a PSA off-gas as fuels. The OC was able to fully convert syngas at 880ºC. However, lower conversion rates were observed with methane-containing fuels. The addition of a Ni-based OC was evaluated in order to increase the reactivity of the OC with methane. In spite of this, an absence of catalytic effect was observed for the Ni-based OC. A deep analysis was carried out into the reasons for the absence of catalytic effect of the Ni-based OC. The performance of the iron ore with regard to attrition and fluidization behaviour was satisfactory throughout 50 hours of hot operation in the continuous CLC plant. Thus, this low cost material is a suitable OC for gaseous fuels mainly composed of H2 and CO.