Economic Comparison of Selected Scenarios for Electrostatic Precipitators and Fabric Filters

Compliance with particulate standards for utility boilers burning low sulfur western coal has resulted in the installation and proposed installation of several fabric filter collectors where cold or hot electrostatic precipitators would have traditionally been applied. Recently, SO3 conditioning has been used to improve cold precipitator performance resulting in considerable reduction in specific collection area (SCA). All this suggests that trade-offs exist indicating ranges of SCA, A/C ratio, and power plant size (Mw) where fabric filters become competitive with electrostatic precipitators. Conceptual cost models are presented which indicate total capital investment and annual costs for the control devices. Precipitator costs are correlated with collecting area, gas flow rate, and power input and are presented as functions of SCA and Mw. Fabric filter costs are keyed to gross filter area, pressure drop, and gas flow rate. Fabric filters become competitive when a cold precipitator requires SCAs in excess of 600 to 800 and competitive when a hot precipitator requires equivalent cold precipitator SCAs in excess of 600 to 1000 depending on A/C ratio, Mw, and hot precipitator SCA credit allowance. The S0₃ conditioned precipitator scenario is shown to be economically competitive with fabric filters.