中国燃煤大气硒排放及其污染控制

Emission and control of atmospheric selenium from coal combustion in China

硒是煤中挥发性的有害痕量元素之一。在高温燃烧条件下,煤中的硒几乎全部挥发进入大气中,对周围大气环境及公众健康产生有害影响。中国煤中硒赋存形式多样,主要分布于黄铁矿和有机质中,且在有机质中存在形式复杂;中国煤的含硒质量分数(4～5mg/kg)高于世界平均水平(3mg/kg),而高硒区燃用高硒石煤是硒中毒事件发生的直接原因;在煤燃烧过程中,硒主要以气态形式进入大气环境。从煤中硒的赋存状态、含量分布、煤燃烧过程中硒的形态转化和排放特征以及燃煤大气硒污染控制措施等方面进行了分析研究。目前,控制燃煤大气硒污染的可行措施主要包括燃煤前选煤除硒、燃烧过程中加入固硒剂及燃烧后使用固体吸附剂等。

Selenium （Se） is one of the hazardarous volatile trace elements in coal. Selenimu will be almost completely emitted into the surrounding environment when coal is burnning, leading to adverse effects on eco-environment and human health. The occurrence of selenium in coal of China is primarily in pyrite and organic mode, and the organic mode is very complicated. The selenium content （4-5 mg/kg） in coal of China is much higher than the world averaged level （3 mg/kg） and burning high-Se hard coal directly causes selenium poisoning accidents. During coal combustion, selenium is emitted mainly as gaseous phase. The occurrence, content and distribution of selenium in coal, selenium speciation and emission characterization during coal combustion, as well as selenium pollution control technology are discussed in detail. At present, washing coal before combustion, using selenium-fixation agent during coal burning and solid adsorbents in flue gas treatment are feasible measures to control atmospheric selenium pollution in China.