There is an urgent need to understand sorbent tolerance for capturing Carbon dioxide (CO 2) in the presence of sulfur dioxide (SO 2). Sulfur oxide is emitted together with CO 2 from various combustion systems and can cause severe air pollution. In this study, the behavior of different dopants on the performance of calcium oxide (CaO) sorbent for capturing CO 2 in the presence of SO 2 was investigated. Three main sets of experiments were carried out to study carbonation and sulfation both separately and simultaneously using a thermogravimetric analyzer (TGA). The results show that SO 2 reduced the capability of the sorbents for capturing CO 2 because of the competition between carbonation and sulfation reactions. Formation of calcium carbonate (CaCO 3) and calcium sulfate (CaSO 4) took place upon carbonation and sulfation, respectively. Our TGA and X-ray photoelectron spectroscopy (XPS) results indicate that the carbonation is totally reversible, while this is not the case with the sulfation. The permanent residual weight gained by the sorbents during the course of sulfation is attributed to the irreversible formation of sulfate species, which is confirmed by both the TGA and XPS results. The Ce promoted CaO sorbent exhibits the best performance for CO 2 capture and is the most SO 2 tolerant sorbent. On the other hand, the Mn doped dopant has the strongest affinity for SO 2.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering