The primary objective of this work is to compare the performance of metallic collecting surfaces to the performance of membrane collecting surfaces in a wet electrostatic precipitator (ESP), in terms of their efficiency in removing fine particulates, acid aerosols, and mercury from an actual power plant flue gas stream.  The relative durability and overall cost-effectiveness of the membrane collectors versus metallic collectors will also be evaluated. Due to the higher specific powers, superior corrosion resistance, and better wetting and cleaning qualities, the membrane-collecting surface is expected to perform better than the metallic surface. The second objective of the project will be to compare the overall fine particulate, acid aerosol, and mercury removal efficiency of the baseline flue gas treatment system on BMP Units 1 and 2 to the efficiencies obtained when the two wet ESP systems (metallic and membrane collectors) are added to the existing treatment system.

This project will involve Croll Reynolds Clean Air Technology (CRCAT), Southern Environmental Inc. (SEI), and Ohio University (OU).  An 18-month evaluation program will be conducted at Penn Power’s Bruce Mansfield Plant (BMP) in Shippingport, PA, using a slipstream of flue gas from the exhaust of the venturi scrubbing system at BMP Units 1 and 2.  Most of the testing will take place in the saturated up-flow pilot wet ESP unit already installed at BMP, and will address the key applications of membrane collectors in wet precipitation.  The ability of the wet ESP unit to collect fine particulate, acid aerosols, and mercury will be quantified through a combination of analyses on isokinetic samples drawn from the inlet and outlet of the wet ESP using EPA Method 5.  Fine particulate removal will be quantified through particle sizing and concentration measurement using differential mass measurements and a Malvern Mastersizer, while acid aerosol removal will be quantified using SO₃ measurements via alternative methods, both using the process First Energy currently employs (a combination of wet chemistry and cascade impactors) and Consol’s Controlled Condensation method. Mercury concentration and chemical speciation measurements will be performed using the modified Ontario Hydro method.  The properties of the membrane that define its sustainability for use (such as burst strength, water transport, and fiber spacing) would be measured at Ohio University after removal from the pilot unit.  In order to compare the overall pollutant removal efficiencies of the alternative flue gas treatment systems (venturi scrubbers alone versus venturi scrubbers with both types of wet ESP’s), data will be obtained on the concentrations of fine particulates, acid aerosols, and mercury species typically present in the flue gas immediately upstream of the venturi scrubbing system.