Most of today's market (1987) is in the 50,000 to 200,000 ft2 plate area size range. ESP selling prices have increased very little over the past 10 years because of more effective designs, increased competition from European suppliers, and a shrinking utility market. Design improvements have allowed wider plate spacings that reduce the number of internal components and higher plates and masts that provide additional plate area at a low cost. Microprocessor controls and energy management systems have lowered operating costs.
Few, if any, hot-side ESPs (those used upstream from an air preheater on a combustion source) are being specified for purchase. Recognition that low-sodium coals tend to build resistive ash layers on the collection plates, thus reducing ESP efficiency, has almost eliminated sales of hot-side units. Of the 150 existing units, about 75 are candidates for conversion to cold-side units (using resistivity conditioning agents) over the next 10 years (U.S. EPA 1990).
Specific industry application has little impact on either ESP design or cost, with the following three exceptions: paper mills, sulfuric acid manufacturing plants, and coke byproduct plants. Because paper mills have dust that can be sticky and difficult to remove, paper mill ESPs use drag conveyer hoppers. These hoppers increase the cost by approximately 10 percent of the base flange-to-flange equipment cost. For emissions control in sulfuric acid plants and coke by-product ovens, wet ESPs are used. In sulfuric acid manufacture, wet ESPs are used to collect acid mist. These precipitators usually are small and use lead for all interior surfaces; hence, they normally cost $65 to $95/ft2 of collecting area installed (mid-1987 dollars) and up to $120/ft2 in special situations. Using Figure , the standard cost for a rigid-frame ESP ranges from $7 to $14/ft2 of collecting area. In addition, a wet circular ESP is typically used to control emissions from a coke oven offgas detarring operation. These precipitators are made from high-alloy stainless steels and typically cost $90 to $120/ft2 installed. Because of the small number of sales, small size of units sold, and dependency of site-specific factors, more definitive costs are not available.
Dry-type rigid electrode ESP flange-to-flange purchase price versus plate area
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