Reduction of Air Emissions by Installation of a Fluidized Bed Boiler, 1993 Environmental Conference Proceedings

Boise Cascade’s Rumford, Maine Mill is a large integrated pulp and paper mill producing 965 tons/day of kraft pulp and 1500 tons/day of coated and uncoated papers. Before 1990, the mill’s steam was supplied by four oil-fired boilers, a bark/oil boiler, and a kraft recovery boiler. In order to reduce SO2 and particulate emissions and the consumption of fuel oil, the company elected to install two new cogeneration boilers to replace three of the oil fired boilers. The new boilers were designed and permitted to fire a combination of coal, biomass, and oil. The emissions control device selected was a limestone circulating fluidized bed for SO2 control, and a four-field electrostatic precipitator for particulate control.

The particulate emissions limit for each boiler was set at .03 lbs./MMBTU, and the SO2 limit at 0.28 lbs./MMBTU for a combination of coal and biomass firing, and 0.32 lbs./MMBTU for coal firing. The NOx limit was set at 0160 lbs./MMBTU for coal and biomass firing. Emissions monitoring data collected following startup in early 1990 indicated that the boilers were comfortably meeting their SO2 and NOx limits. Following a few months if boiler operation, each boiler passed its particulate emission test. This paper describes the operating history of the boilers from startup to the present, including the improvement in boiler uptime to the 95% level. Actual emission data is summarized and compared to the stringent operating limits.