Effect enhanced lime/limestone

Since forced oxidation converts sulfite to sulfate, it has an adverse effect on SO2 removal in an unenhanced lime system in which sulfite is the major SO2 scrubbing species. This is also true in MgO-enhanced lime and limestone systems in which the promotion of SO2 removal relies on an increased sulfite-bisulfite buffer. When adipic acid is used with lime, calcium adipate becomes a major buffer species therefore, both good SO2 removal and sulfite oxidation can be achieved using within-scrubber-loop forced oxidation. 

Process Control Process response to changes in SO2 concentration is slower than with a Mg-enhanced lime system due to the time it takes CaCOs to dissolve. Process response to SO2 concentration changes is more flexible and forgiving than for a limestone system due to the buffering effect of the magnesium sulfite. 

Ireland, P., and Ogden, G, 1991, FGD Economics A Comparison of Magnesium-Enhanced Lime and Limestone Forced Oxidation Systems," Proceedings Acid Rain Retrofit Seminar, The Effective Use of Lime, sponsored by the National Lime Assoc. (Arlington, VA), Pittsburgh, PA, Jan. 9-10, pp. 123-137. 

The relative effects of 10% of fly ash, limestone, or sludge on the hydration of portland cement have been investigated by DTA/DTG/TG and XRD. Based on Ca(OH)2 estimation, it has been concluded that lime sludge and limestone enhance hydration of cement compared to that by slag or fly ash.l ]... 

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