Atmospheric emissions estimation of Hg, As, and Se from coal-fired power plants in China, 2007

Over half of coal in China is burned directly by power plants, becoming an important source of hazardous trace element emissions, such as mercury (Hg), arsenic (As), and selenium (Se), etc. Based on coal consumption by each power plant, emission factors classified by different boiler patterns and air pollution control devices configuration, atmospheric emissions of Hg, As, and Se from coal-fired power plants in China are evaluated. The national total emissions of Hg, As, and Se from coal-fired power plants in 2007 are calculated at 132 t, 550 t, and 787 t, respectively. Furthermore, according to the percentage of coal consumed by units equipped with different types of PM devices and FGD systems, speciation of mercury is estimated as follows: 80.48 t of Hg, 49.98 t of Hg2+, and 1.89 t of HgP, representing 60.81%, 37.76%, and 1.43% of the totals, respectively. The emissions of Hg, As, and Se in China's eastern and central provinces are much higher than those in the west, except for provinces involved in the program of electricity transmission from west to east China, such as Sichuan, Guizhou, Yunnan, Shaanxi, etc.

Research Highlights
► Atmospheric emissions of Hg, As, and Se from coal-fired power plants in China are estimated.
► The total emissions of Hg, As, and Se are about 132.35 t, 550.08 t, and 786.83 t in 2007.
► Speciation of mercury is estimated as follows: 80.48 t of Hg0, 49.98 t of Hg2+, and 1.89 t of HgP.
► Hg, As, and Se emissions are mainly discharged from plants in China's eastern and central provinces.
► Combined factors are presented to reflect the emission levels through burning per Mt coal in power plants by province.