Effects of Recent Operating Experience on the Design of Spray Dryer FGD Systems

Abstract

The information presented in this paper is directed to those who are involved in specification or purchase of flue gas desulfurization (FGD) systems. Spray dryer FGD systems have been in service on full-scale electric utility applications for about 4½ years. When introduced, this process appeared to provide reduced capital and annual costs and easier waste handling and disposal, compared to the wet scrubber FGD system. However, at the time that the first generation of this new FGD process was under design, a number of design questions were unresolved. These questions involved spray dryer sizing criteria, the number and type of atomizers, optimum reagent preparation and waste handling subsystems, and the effects of low temperature operation on the particulate removal equipment. The operating experience of these first generation spray dryer FGD systems has both confirmed their suitability for the electric utility environment and identified areas where improvement is needed. Problem areas include deposit buildup in the spray dryer, pluggage in the atomizers and waste handling equipment, and the potential for increased corrosion in the particulate collection equipment. The correction of these problems will require a combination of modifications to the spray dryer FGD process and to the types of equipment selected.