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INFLUENCE OF COAL MINERAL MATTER ON THE EFFECTIVENESS OF DRY SORBENT INJECTION FOR SO2 CONTROL
Citation:
Slaughter, D., W. Thomson, T. Peterson, S. Chen, AND W. Seeker. INFLUENCE OF COAL MINERAL MATTER ON THE EFFECTIVENESS OF DRY SORBENT INJECTION FOR SO2 CONTROL. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/7-87/020.
Description:
The report describes the use of laboratory-, bench-, and pilot-scale facilities to examine the impact of mineral matter on calcium-based sorbent reactivity toward SO2. Two areas of concern were investigated: (1) deleterious effects of coal ash; and, (2) beneficial (promoter) effects of additive and ash minerals. The mechanisms of sorbent/mineral interactions were also studied using a variety of sophisticated techniques, including scanning electron microscopy, energy dispersive spectroscopy, x-ray spectroscopy, x-ray microprobing, and dynamic x-ray diffractometry. Coal ash deactivation was shown to occur through the formation of calcium silicates which reduces calcium availability and promotes sintering of the sorbent. However, this mechanism was found important only when the ash and sorbent were intimately contacted prior to firing. Alkali metals and chromium-series transition elements were found to promote sorbent reactivity. The basic mechanisms involved the increase of mass transfer within sorbent particles by altering the pore structure, as well as increased solid product layer diffusion (increased ion mobility). The alkali metals were also found to react directly with SO2.