300MW煤粉锅炉砷排放特征的实验研究

对某台装备静电除尘装置的300MW燃煤电站锅炉的煤,底渣,电除尘器4个电场飞灰进行取样并测定了其中砷的含量.采用美国国家环保局推荐的EPA method 29方法测定了电除尘器后排放烟气中砷分布情况.结果表明,砷主要以飞灰形式排放,占到原煤总砷量84.6%,而底渣和烟气分别只占0.53%,2.16%.直接计算砷的质量平衡率为87.2%,电除尘器后烟道中以气相形式存在的砷为2.5μg/m³.飞灰中砷的含量与粒径密切相关,随着粒度的降低而升高.

Characterization of Arsenic Emissions from a Coal-Fired Power Plant

An emissions study for arsenic was conducted at a 300 MW coal-fired plant equipped with an electrostatic precipitator. The input and output streams such as coal, slag, ESP ash, and flue gas containing the post-ESP particulates were collected. Gaseous arsenic was sampled using EPA method 29 and the arsenic concentrations in the samples were measured using inductively coupled plasma atomic emission spectrometry (HG-ICP-AES). The mass balance recovery of arsenic estimated in this study was 87.2%. Arsenic concentration in stack gas was 2.5 microg/m3. Approximately 0.53% of the coal-derived arsenic was incorporated into slag, 84.6% of the arsenic was found on the fly ash collected by electrostatic precipitators, and 2.16% was found in the vapor phase. The relationship between arsenic concentration and ash particle size was also assessed, and arsenic is significantly concentrated in the small sized particles.