Mercury emissions and partitioning from Indian coal-fired power plants

• Published in: Journal of environmental sciences (China) Vol. 100; pp. 28 - 33
• Main Authors: Agarwalla, Hridesh, Senapati, Rabi Narayan, Das, Tarit Baran
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-02-2021
• Subjects: Air Pollutants - analysis; Coal - analysis; Coal Ash - analysis; Coal combustion; Emission; Flue gas; India; Mercury; Mercury - analysis; Power Plants; Thermal power plant; India; Coal combustion; Emission; Mercury; Flue gas; Thermal power plant
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2020.06.035

In India coal combustion is the single largest source of emission of mercury which is a wide-spread persistent global toxicant, travelling across international borders through air and water. As a party to the Minamata convention, India aims to monitor and reduce Hg emissions and stricter norms are introduced for mercury emissions from power plants (30 μg/Nm3for flue gas in stack).
This paper presents the results obtained during the experimental studies performed on mercury emissions at four coal-fired and one lignite-fired power plants in India. The mercury concentration in the feed coal varied between 0.12–0.27 mg/Kg. In the mercury mass balance, significant proportion of feed coal mercury has been found to be associated with fly ash, whereas bottom ash contained very low mercury. 80%–90% of mercury was released to air through stack gas. However, for circulating fluidised bed boiler burning lignite, about 64.8% of feed mercury was found to get captured in the fly ash and only 32.4% was released to air. The mercury emission factor was found to lie in the range of 4.7–15.7 mg/GJ.
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