Effect of Moisture Conditioning and Handling on Leaching and Physical Properties of Sodium Bicarbonate Flue Gas Desulfurization Materials

摘要

Flue gas desulfurization(FGD)systems at coal-fired power plants using sodium bicarbonate are becoming more common.The FGD from a sodium bicarbonate system may have different characteristics than the byproduct from a lime or limestone based FGD system,since the primary product of the scrubbing is sodium sulfate or sulfite rather than calcium sulfate or sulfite.These differences may become important when these coal combustion residuals(CCR)are landfilled,particularly if water is added for dust control prior to transport.The effects of different moisture conditioning and handling procedures on the physical and leaching characteristics of the FGD byproduct were investigated to provide insight into the best ways to handle the byproduct at a landfill.The amount of water added had a significant impact on the strength and hydraulic conductivity of the FGD byproduct,while having much less impact on the leaching behavior.Whether the wetted FGD byproduct is compacted or allowed to form pellets has a major impact on the hydraulic conductivity and leaching behavior of the byproduct.Thus,FGD byproduct handling practices at the landfill may have a major impact on both the physical and leaching characteristics of the material.