Very common to use dry Ca(OH)2 upstream of a baghouse for SO2 removal. Gas temp should be as low as possible (325F?)without causing corrosion and material handling problems with ash.
Expect to use a lot of lime - suggest NSR= 4-6 to get 75% reduction.
Recommend maintaining scrubber pH nuetral. 2 advantages are 1) can use mild steel, 2) won't have to nuetralize afterwards.
ammonia is easliy scrubbed, even in a venturi-type scrubber
