| Contents Notes |
Results are presented from a laboratory-scale investigation of the reactivity of calcium-based sorbents for SOb2s capture after calcination at furnace operating temperatures (1200-1950ÀC). This work was undertaken to provide fundamental information for developing SOb2s emission control technology in pulverized-coal-fired utility boilers. Pulverized sorbents (<100 [mu]m diameter) were calcined by injection into a laboratory gas flame reactor. Experimental variables were time, temperature, gas composition, limestone type, and particle size. Samples were collected for analysis of surface area, extent of calcination, particle size distribution, and reactivity toward SOb2s. Also investigated were fuel-rich sulfur capture, regeneration of sulfur species into the gas phase, and the effects of fly ash on specific surface area and SOb2s capture. Particle heating, calcination, and surface area development occurred typically in 25-35 ms. Measured surface areas increased with decreasing calcination temperature; the range for a calcite, Vicron 45-3, was 3-15 mp2s/g at 1200-1830ÀC. Surface areas for dolomite reahed 25 mp2s/g. The general order of SOb2s reactivity was dolomite>calcium hydroxide> calcite. Fly as materials reduced both the surface area and the SOb2s reactivity of the sorbents tested: calcite was affected the most, and dolomite the least. An approximately linear correlation was found between SOb2s reactivity and specific surface area which covered both limestones and limestone/mineral mixtures. |
