8
HCl Control Technologies
•Effect
of alkali cost on technology choices
§Wet FGD
Lime/limestone used
in largest FGD units
•800
MW electric generating plant
Lime used in medium
and large FGD units
•Waste-to-energy
plant
Caustic used in small
units
•Refinery
cat cracker unit
§Relative costs of limestone/lime/caustic:
2 years ago:
1/3/15
Now: 1/3/25
§Shift smaller units to dual-alkali wet FGD
or dry FGD