Targeting Chlorides in Coal-Fired Power Station FGD Waste Streams

At wet-scrubbed coal-fired power stations, the combustion of chlorine-laden coal introduces chlorides into the subsequent flue gas desulfurization (FGD) system wastewater and settling ponds. A 1,500-MW power station is planning to enhance chlorides control within its FGD system to prevent a buildup of chlorides that would render their scrubbers inoperable. The anticipated regulatory consequences of creating a new liquid discharge coupled with the local regulatory concern about chloride impacts drive the need for a Zero-Liquid Discharge (ZLD) treatment system to provide the necessary purge of chlorides.The primary objective of this report is to provide a case study for the use of ZLD technology to remove and immobilize chlorides from FGD waste streams. Presented herein is a summary of the detailed evaluation completed as part of the conceptual design and preliminary cost estimate for this ZLD chloride treatment system.