Retrofit Particulate Emission Controls on Two Oil-Fired Power Boilers, 1993 Environmental Conference Proceedings

Modernization of the Rumford Mill has required two residual oil-fired power boilers to reduce particulate emissions to levels specified by the State of Maine Department of Environmental Protection (DEP). The paper describes operational and hardware changes made to one of the two boilers and a wet scrubber.

The boiler’s firing conditions were adjusted to reduce soot and SOs levels. Backend temperatures were raised to limit premature acid aerosol condensation. The single throat venturi was replaced and Multiwirs were added to enhance the collection of fine particulates. Operationally, the differential pressure across the scrubber was increased to 6.2 kPa (25” H,O) and the pH of the recycle spray was increased to promote acid aerosol collection. These changes demonstrated compliance with DEP requirements.

The capacity of the wet scrubber will be increased to accommodate gas flow from both boilers. A second venturi will be added to the scrubber discharging into a common separator. Conditioning towers will be installed above both venturis to promote particle growth and submicron particle collection. This configuration is expected to achieve compliance on both boilers while minimizing space requirements, exhaust gas ducting, and overall project costs.