Cyclic Regeneration of Pyrolusite-Modified Activated Coke by Blending Method for Flue Gas Desulfurization

The regeneration properties of a novel pyrolusite-modified activated coke (ACP) by blending method were investigated. Cyclic regeneration of ACP (ACP-Rn) shows the ACP was a good desulfurizer. The sample had the best desulfurization performance after five regeneration cycles (ACP-RS), and its sulfur capacity was 178 mg/g, 10.8% higher than that of ACP (161 mg/g). The S-BET and pore volume were increased with the number of regeneration cycles, but they were not the limiting factors of the SO2 removal. The better surface functional groups, especially the basic sites, contributed more to the improvement of desulfurization performance of ACP-Rn. The loaded metals played an important role in SO2 removal. The accumulation of metal sulfate in ACP rapidly increased from the first to fifth regeneration cycles and then remained relatively stable during further reuse. The ACP regeneration process divided into three stages: drying, reaction, and pyrolysis. The wrapped metals relatively enhance the pyrolysis and acted as further surface modifications.