1980—2007年我国燃煤大气汞、铅、砷排放趋势分析

基于文献调研,对1980—2007年我国汞、铅、砷3种主要燃煤大气重金属排放清单进行归纳,计算了3种重金属的逐年平均排放量,并分析排放量与燃煤量的相关性、单位煤耗大气重金属污染物排放量的变化趋势及原因. 结果表明:1980—2007年我国燃煤大气汞、铅、砷排放量与燃煤量增长趋势基本一致,均呈显著正相关(R2分别为0.911、0.971、0.996),但燃煤大气汞排放量与燃煤量间的相关性却比铅、砷排放量与燃煤量的相关性小很多,这主要是燃煤电厂对汞协同脱除能力比对铅、砷强,以及电厂汞排放所占比例较大所致. 燃煤大气汞排放量在2005年后趋于稳定,而铅、砷排放量在2000年后快速增长,年均增速均超过10%,其中电厂和工业锅炉是重金属排放的重点行业. 在燃煤量不断增长的背景下,单位煤耗的大气汞、铅排放量均呈下降趋势,其中汞排放量在2005—2007年年均降低5.0%,铅排放量在1996—2007年年均降低1.7%. 这与我国主要燃煤行业除尘、脱硫、脱硝等大气污染控制装置对重金属的协同脱除能力不断增强有密切关系. 

Analysis of Atmospheric Emission Trends of Mercury, Lead and Arsenic from Coal Combustion in China from 1980-2007

Based on the summarization of the inventories of main heay metals from coal combustion, the annual emissions of mercury, lead and arsenic were calculated. The correlation between emission and coal consumption were further analyzed from 1980-2007. Meanwhile, the trends and causes of the emissions per unit coal consumption were also investigated. The results showed that atmospheric mercury, lead and arsenic emissions from coal combustion generally synchronized with coal consumption from 1980-2007. There was a significant correlation between atmospheric emissions of three heavy metals and coal consumption with squared correlation coefficients, 0.911,0.971and 0.996, respectively. Moreover, the correlation between atmospheric mercury emissions and coal consumption were much less than those between lead, arsenic and coal consumption. This is mainly caused by that power plants have stronger combined removal capacities for mercury, as well as the proportion of atmospheric mercury emissions from power plants was larger than lead and arsenic. Atmospheric mercury emissions were kept stable after 2005, whereas both lead and arsenic rapidly increased 10% annual average rates after 2000. Power plants and industrial sectors were the main sources of three heavy metals from coal combustion in China. Contrary to the continuous increase of coal consumption in China, both atmospheric mercury and lead emissions per unit coal consumption generally declined from 1980-2007. Atmospheric mercury emissions were greatly cut down after 2002and averagely decreased by 5.0% from 2005to 2007. Atmospheric lead emission per unit coal consumption displayed an obvious reduced its trend after 1996, decreasing by 1.7% annually. The trends were mainly contributed by the combined removal capacities for heavy metals by new air pollution control devices (APCDs), such as fabric filter (FF), electrostatic precipitator (ESP), wet flue gas desulphurization (WFGD) and De-NO_x, developing in the main coal combustion industries.