“Hot” versus “Enlarged” Electrostatic Precipitation of Fly Ash: A Cost-Effectiveness Study

Abstract

This paper considers the problem of designing precipitators (for coal-fired electric power plants) which are cost-effective in the collection of low sulfur fly ash. “Hot” and “enlarged” precipitators are analyzed. A hot precipi-tator reduces fly ash resistivity, an enlarged precipitator increases treatment time, and both are capable of precipitating low sulfur fly ash at high collection efficiencies. In a parametric comparison of hot and enlarged precipitation costs it is found that an enlarged precipitator is likely to be less costly at high collection efficiencies.

The analysis uses data on 37 full scale precipitator systems to determine an empirical Deutsch-type efficiency equation. The predictive power of this equation is shown to be quite good in several tests using data from some additional precipitator systems which are treating low sulfur fly ash. Precipitator installation costs are estimated by minimizing precipitator accounting costs subject to this empirically derived efficiency equation. These costs plus others are derived both for hot and enlarged precipitation and serve as a base for making cost comparisons. The cost comparisons themselves use a range of cost parameters designed to cover widely varying plant and locational circumstances.