Release characteristics of elemental mercury during low calorific value coal combustion.

Abstract

The dynamic release characteristics of Hg0 during low calorific value coal combustion were investigated in a combining laboratory-scale furnace coupled with atomic fluorescence spectroscopy. The results show that the sulfur has an inhibitory effect on the homogeneous oxidation of Hg0 in flue gas. The instant intensity of Hg0 release increases with increasing temperature while the amount of Hg0 release gradually decreases with increasing temperature. Compared with that under air, the instant intensity of Hg0 release under O2/CO2 atmosphere increases to some extent with a lower decreasing rate of Hg0 release peak. The release ratio of elemental mercury (Hg) from Yuwu (YW) and Qinxin (QX) coal increases while that from Yonghao (YH) coal decreases under O2/CO2 atmosphere. In the range of 800–1100°C, the release rate of Hg reaches more than 96% under the residence time of 50 s.