Evaluation of a highly reactive and sulfur resistant synthetic Fe-based oxygen carrier for CLC using gaseous fuels

Abstract

Because of its low cost and environmental compatibility, Fe-based oxygen carriers are now being considered as an attractive option for chemical-looping combustion (CLC) applications. In this work, a synthetic Fe-based oxygen carrier made by impregnation using Al2O3 as support was evaluated with respect to gas combustion in a 500 Wth CLC continuous unit using CH4 as fuel during long-term operation. Furthermore, a study on the fate of sulfur during CH4 combustion was carried out with this oxygen carrier.

During the experimental tests, it was observed that an increase in the oxygen carrier-to-fuel ratio (φ) produces an increase in the combustion efficiency, reaching full gas combustion at φ values 2 1.5. In addition, the presence of sulfur in the fuel gas did not affect to the combustion efficiency, independently of the amount of sulfur in the gas stream in the range of 700 to 2000 vppm H2S. However, the attrition of this oxygen carrier was higher than other materials used in CLC.

Therefore, it can be concluded that the synthetic Fe-based oxygen carrier developed in this work was highly reactive and sulfur resistant and it can be considered as a suitable oxygen carrier for CLC with gaseous fuels that contain sulfur when the attrition behavior was improved.