Economic Comparison of Flue Gas Desulfurization Systems for Reverberatory Furnace SO2 Control

Abstract

For a number of years, the economic impact associated with applying flue gas desulfurization (FGD) to weak SO2 streams generated by reverberatory smelting furnaces has been the subject of much debate. Consequently, an in-depth economic assessment of demonstrated technologies using new tax laws under the Economic Recovery Tax Act of 1981 has been performed and is presented here. An after-tax discounted cash flow analysis has been used to compare limestone and magnesium oxide-based FGD systems for application to reverberatory furnace offgas streams. As expected, at discount rates of 5–15% per annum, the limestone scrubbing system appears to be the less costly system over a design flow rate range of 60,000–140,000 scfm (at a constant 1% SO2 concentration). The cost advantage of limestone FGD systems, however, decays very rapidly as the volumetric gas flow rate decreases. Thus, for potential applications involving lower design flow rates, the choice of the most economical system is not clearcut.