Calcium Looping: On the Positive Influence of SO2 and the Negative Influence of H2O on CO2 Capture by Metamorphosed Limestone-Derived Sorbents

The CO 2 capture performance of sorbents derived from three distinct limestones, including a metamorphosed limestone, is studied under conditions relevant for calcium looping CO 2 capture from power plant flue gas. The combined and individual influence of flue gas H 2 O and SO 2 content, the influence of textural changes caused by sequential calcination/carbonation cycles, and the impact of CaSO 4 accumulation on the sorbents' capture performance were examined using bubbling fluidized bed reactor systems. The metamorphosed limestone-derived sorbents exhibit atypical capture behavior: flue gas H 2 O negatively influences CO 2 capture performance, while limited sulfation can positively influence CO 2 capture, with space time significantly impacting CO 2 and SO 2 co-capture performance. The morphological characteristics influencing sorbents' capture behavior were examined using imaging and material characterization tools, and a detailed discussion is presented. This insight into the morphology responsible for metamorphosed limestone-derived sorbent's anomalous capture behavior can guide future sorbent selection and design efforts.