Similarities between lime and limestone in wet—dry scrubbing

Lime is utilized as a sorbent in most commercial wet—dry scrubbing processes for SO2 control, while limestone is not considered to be sufficiently reactive for such a purpose. Faced with the fact that limestone is potentially the least expensive sorbent for SO2 control, a study was conducted to uncover ways to increase the reactivity of this sorbent in order to use it in wet—dry scrubbing applications. The study was focused on a comparison of the reactivity of lime and limestone during the dry reaction period. The conditions which have a major impact on the reactivity include the sorption capacity of water vapour, the BET surface area, the relative humidity and the sorbent utilization. The experiments revealed several similarities between the two sorbents, which led to a number of ways to obtain increased limestone acitivity.