INVESTIGATION OF HIGH-REACTIVITY CALCIUM-CARBONATE SORBENT FOR ENHANCED SO2 CAPTURE

Kinetics of ultrafast, high-temperature sulfation is investigated for two calcium carbonates from different sources, a commercial calcium hy droxide and a laboratory-made modified hydrated lime powder. Time-reso lved kinetic data are obtained for a 0-600 ms time scale at a temperat ure of 1080 degrees C with in-situ particle size classification. A mea n particle size of 3.9 mu m is considered for sorbent comparison studi es. It is observed that the high-surface-area Forsby carbonate exhibit s extraordinarily high reactivity (50% in 500 ms) compared to other ca rbonate and hydrate powders. The difference in reactivity is most prom inent in the short time scale of under 50 ms. Thorough investigations of the internal pore structure and surface area evolution in the initi al 50 ms are conducted for both calcination and sulfation. The results elucidate the influence of internal pore structure in determining the initial reactivity and the final sorbent utilization.