Dealing with Fines Accumulation in FGD Gypsum Dewatering

摘要

This paper documents the effects of accumulation of fine particles in the scrubber slurry on the dewatering characteristics of gypsum produced by wet limestone FGD systems, and methods used to mitigate these effects. The effects are documented using data collected from operating FGD systems at which the performance of the FGD gypsum dewatering equipment had degraded significantly. Investigations pointed to accumulation of fine particles in the process slurry as the cause. This paper describes and presents results of mitigation efforts that have been used to enable the slurry to be successfully dewatered using the existing rotary drum vacuum filters. It identifies changes to the FGD process equipment operation that can be implemented to minimize the accumulation of fine particles in the systems. Data presented on the particle size distribution of key process streams from these operating FGD systems will be of use to all FGD system operators.