Ca-based sorbents as precursors of oxygen carriers in chemical looping combustion of sulfurous fuels

Limestone Chemical Looping Combustion process (LCL-C™) patented by Alstom Power Inc. proposes the formation of a CaSO4 oxygen carrier via sulfur retention when supplying Ca-based sorbent together with sulfurous fuels in fuel reactor. In present research work, four sorbents, three limestones and one dolomite different physico-chemical characteristics, have been evaluated as precursors during consecutive redox cycles thermogravimetric analysis. 5% H2 3000 vppm H2S (N2 to balance) 10% O2 were selected reducing oxidizing gases, respectively. Additionally, an anhydrite ore has also studied for comparison purpose. Results from SEM-EDX characterization particles revealed existence sulfation patterns: (1) uniform distribution, (2) core–shell structure (3) high content limitation be converted into CaSO4. All sorbents exhibited transport capacity (Roc = 13.3–20.8%), except material showing pattern 2.6%). Likewise, materials presented reactivity rate index values ranged between 11.0 18.8%/min. Therefore, herein assessed can considered suitable based carriers used CLC systems burning fuels.