The report gives results of an intensive emission testing program to verify the anticipated reduction in both gaseous and particulate air pollutants caused by the conversion of a conventional kraft recovery boiler (utilizing direct contact evaporation) to a new controlled-odor design that eliminates direct contact evaporation. It documents both the cost and emission control capability of the modification. The program also investigated major process variables that affect kraft recovery boiler operation and the emissions resulting therefrom in order to establish boiler operating conditions to minimize emissions. Investigated were: boiler loading, liquor sulfidity, air flow, air distribution, and liquor solids concentration. Particulate emissions were primarily affected by and directly proportional to the amount of black liquor solids burned in the recovery furnace (boiler loading). SO2 emissions were primarily dependent on the sulfidity level of the cooking liquor being recovered. Total reduced sulfur (TRS) emissions were primarily affected by excess oxygen levels, with an increase in oxygen resulting in a decrease in TRS.

"August 1974." "EPA/650-2-74-071a."