Wet-Limestone-Scrubber Research Project, Widows Creek Unit 8. Process Improvement and Optimization, Task-4

摘要

This optimization study was designed to establish the most efficient and economical operating conditions to increase SO sub 2 removal in the Widows Creek Steam Plant unit 8 FGD system. This was done to aid in meeting applicable emission limitations. The overall emission limitation for Widows Creek was established at 1.2 lb SO sub 2 /10 exp 6 Btu of heat input on a 24-hour average. To meet this limitation units 1 through 6 were to burn low-sulfur coal and FGD systems on units 7 and 8 were to reduce emissions to no more than 0.9 lb SO sub 2 /10 exp 6 Btu. To meet the FGD requirements, TVA installed a flue gas desulfurization (FGD) system on unit 7 and optimized SO sub 2 removal efficiency of the existing FGD system on unit 8. The unit 8 FGD system was designed for an overall SO sub 2 removal efficiency of 80%, equivalent to a controlled emission level of 1.2 lb SO sub 2 /10 exp 6 Btu with 4.3% sulfur coal. Modifications considered were the use of different nozzles and the use of additional packing to augment the existing grids. An optimization test program was developed to evaluate the effects of these modifications on SO sub 2 removal efficiency at different flue gas rates, absorbent liquid rates, limestone stoichiometries, and limestone particle sizes. An examination of the data shows that all of the absorber modifications tested increased the SO sub 2 removal efficiency substantially. Particulate removal efficiency exceeded emission control requirements throughout the test period. 17 figures, 6 tables. (ERA citation 08:014667)