Behavior of Mercury in Solid Particles Collected from a Very Cold Electrostatic Precipitator

Abstract

In the present study, the behavior of mercury (Hg^p) in solid particles collected from a very cold electrostatic precipitator (VCEP) with the flue gas temperature of 94°C in a large scale pulverized coal power plant in Japan was examined for ten different coal samples. In addition, the investigation of the Hg^p content for each particle size in five fly ashes clarified the effect of the particle size of unburned carbons on the Hg^p content in fly ash. As a result, the distribution of Hg^p into fly ash collected from the VCEP was 13.6-92.3% and increased with the unburned carbon (0.49-2.84%) in fly ash. The decrease of the flue gas temperature heightened the effect of the unburned carbon on the Hg^p content in fly ash. The shift of approximately 0.2% in the content of the unburned carbon in fly ash led to the change of 5 - 15% in the distribution of Hg^p into fly ash. The increase of the particle size of fly ash heightened the contents of Hg^p and the unburned carbon in fly ash. This suggested that the particle size of the unburned carbon in fly ash significantly affected the formation of Hg^p.