Mercury in coal from south eastern coalfield and mercury partitioning at sub-critical coal-fired power plant

India is considered as one of the major mercury emitters of the world. Coal combustion in power plants is the foremost source of mercury emissions. Coal samples from South Eastern Coalfield (SECL) region, India were assessed for mercury content and its partition in a 500 MW boiler unit of a coal-fired power plant. Hg content in the runoff mine coal samples varied from 0.011 to 0.188 mg/kg. The Hg content in coal was positively correlated with ash and sulfur. In the power plant, about 65% of the Hg present in the feed coal was emitted through stack, whereas the rest were associated with the fine fly ash (33%), bottom ash (1.9%), and mill rejects (0.1%).The concentration of total Hg in the stack gas varied from 8.5 to 13.7 μg/Nm 3 , wherein Hg 0 (74–81%) was much higher than Hg 2+ (19–26%). The estimated mercury emission factor was 1.0–3.2 mg/GJ, which is comparatively higher due to the use of high ash coal and the lack of flue gas desulphurisation system. Hg portioning along the flue gas hoppers were also investigated which indicates relationship between Hg adsorption and carbon/sulfur content of the fly ash.