FGD Performance and Experience on Coal-Fired Plants
AUTHOR: Mitsuru Takeshita and Hermine Soud
DATE: July 1993
FGD technology has made considerable progress in terms of SO2 removal efficiency, reliability, and capital/operating costs over the last decade - as SO2 emission regulations have become more stringent throughout the world. The regulations have been based generally on the best available technology. This report examines the performance and experience of state-of-the-art FGD systems available commercially, with special emphasis on the advanced wet limestone scrubber. It also focuses on how electric utilities have complied with stringent regulations.
Reliability of FGD systems has improved to over 99% through a better understanding of FGD chemistry and engineering. Capital and operating costs of the wet limestone scrubber have been reduced by 20-30% - mainly as a result of simplification of the system configuration. This has also brought a considerable reduction in power consumption.
This report also reviews the applicability, performance and cost-effectiveness of the alternative FGD systems such as spray dry scrubbers, sorbent injection, regenerable and combined SO2/NOx removal processes. These are used mainly for relatively small to medium capacity power plants using low to medium sulphur coal or where the available land is too limited for storage of reagent and for disposal of the waste product. However, the market share for these FGD systems is small. Brief case studies demonstrate selection of the most suitable FGD system for each individual power plant, depending on site-specific conditions.