Abstract |
The report gives results of a program to provide process design information for sorbent utilization as applied to EPA's LIMB process. Specifically, the program was designed to investigate the role of boiler thermal history, sorbent injection location, Ca/S molar ratio, and SO2 partial pressure on capture effectiveness with limestones, dolomites, and slaked limes with and without metallic promoters. The experimental studies were supported by theoretical calculations using grain and pore models that considered both the heterogeneous chemical reaction and the relevant diffusional processes. The experimental results and the sulfation model calculations indicate that the sorbent injection locations and the residence time within the sulfation temperature window can significantly influence overall sulfur capture for any sorbent. Unless the sorbent is promoted with a metal additive, downstream injection at about 1500 K results in optimum sorbent utilization. |