Release characteristics of elemental mercury during low calorific value coal combustion

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.