A major pulp and paper mill located in New England, USA was faced with a control order to reduce SO2 and a schedule challenge to meet the order deadline and steam requirements. In addition, the customer was looking for ways to save reagent cost.
Macrotek was selected to design and build two wet FGD systems for two 100,000 lbs/hr medium sulfur coal fired boilers. The design included a two-stage spray tower configuration. In the first stage, waste alkaline liquid was used to neutralize a portion of the SO2 and a second polishing caustic stage was used for enhanced removal efficiency. Two benefits were realized; first, the waste alkaline liquid did not require further acid neutralization and second, there was a significant reduction of caustic reagent consumption.