Capturing Characteristic of Gaseous Mercury in Desulfurization Solutions Simulating the Limestone-Gypsum Process

Combustion flue gases have particulate and gaseous mercury. Particulate mercury is captured in an electrostatic precipitator (EP) as fly ash but gaseous mercury passes through an EP and flows into a wet-flue gas desulfurization (wet-FGD) unit in combustion plants. Besides, gaseous mercury takes elemental and oxidized forms (Hg0 and He2+) in combustion flue gases, these chemical forms have great influence on the behavior of gaseous mercury in a wet-FGD unit.The behavior of Hg0 and Hg2+ in water and calcium compound slurries simulating limestone-gypsum process, which is one of wet-FGD systems, has been studied. It was clarified that almost of Hg0 passed through the solutions, on the other hand Hg2+ was captured in it and some captured He was converted into Hg0, which was released from the solutions. The conversion ratio of Hg2+ into Hg0 was influenced by gas and solution conditions.