Performance of a highly reactive impregnated Fe2O3/Al2O3 oxygen carrier with CH4 and H2S in a 500 Wth CLC unit

• The effect of H2S on the CLC process using a Fe-based oxygen carrier was analyzed.
• The presence of H2S hardly affected the reactivity and the combustion efficiency.
• All the sulfur fed was released as SO2 in the flue gas from the FR.
• No sulfur was detected in the oxygen carrier particles.
• This impregnated Fe-based oxygen carrier was highly reactive and sulfur resistant.

A synthetic Fe-based oxygen carrier prepared by impregnation using γ-Al2O3 as support, successfully tested for gas CLC combustion, has been now evaluated with respect to gas combustion in a 500 Wth CLC continuous unit when the fuel, CH4, contained variable amounts of H2S.Full gas combustion was reached at oxygen carrier-to-fuel ratio values higher than 1.5. The presence of sulfur in the fuel gas hardly affected the reactivity and combustion efficiency of the oxygen carrier, independently of the amount of sulfur in the gas stream. All the sulfur introduced as H2S in the fuel reactor (FR) was released in the same reactor as SO2. Furthermore, oxygen carrier particles extracted from the CLC unit after the experimental tests with H2S addition were characterized by means of different techniques and no sulfur was detected in any case. The impregnated Fe-based oxygen carrier was highly reactive and sulfur resistant, and can be considered as a suitable material for CLC with gaseous fuels that contain sulfur.