Formation characteristics of Hg particulates during combustion of different coals

Combustion experiments (3 coals, 3 coals with addition of 1%, 3%, 5% CaBr₂ and Ca(CH₃COO)₂, and a coal with addition of Fe₂O₃) were conducted on a high temperature electric heating reactor at 1 250℃. The fly ashes were collected and the particulate Hg (Hg_p) contents were analyzed. The specific surface area, EDS, and XRD analysis were performed. It is indicated that the Hg_p formations characteristics of the 3 coals were rather different. The ash of coal 3 has the largest specific surface area, but the lowest Hg content and Hg_p ratio in its ash. CaBr₂ addition leads to significant increment of Hg content in ash and Hg_p ratio. Ca (H₃COO)₂ and Fe₂O₃ addition do not lead to prominent increase of Hg_p.