改性活性焦脱除烟气中汞的实验研究

Experimental Research of Removing Mercury From Flue Gas by Modified Activated Coke

利用KClO3和KCl等5种改性剂对活性焦进行改性处理,并且对改性样品在固定床实验台架上进行了吸附脱汞实验研究,发现含Cl化合物改性样品极大地促进了脱汞能力,并对其化学吸附机理进行了深入的分析,表明C=O官能团在吸附脱汞过程中起到非常重要的作用。随着吸附反应温度的升高,物理吸附降低而化学吸附上升,150℃时脱汞效率最高;水蒸气的存在使浸氯活性焦脱汞效率下降;随着改性剂中氯浓度的升高,脱汞效率升高;样品进行热处理后,随着热处理温度的升高脱汞效率下降。

An experimental study was conducted with a bench-scale fixed bed, on the capture of elemental mercury （Hg^0） from simulated flue gas using modified activated cokes （ACs）. The performances of five modified ACs, which impregnated with potassium chloride （KC1） solution and potassium chlorate （KClO3） solution et al, were evaluated. The experimental data suggests that adsorptive capacity for Hg^0 is significantly enhanced for chloride-impregnated ACs. The functional groups of the carbons-oxygen double bonds （C=O） are very important for the processes of Hg^0 chemisorption and the mechanisms of adsorption onto the chloride-impregnated ACs are also proposed. With increasing temperature, physical adsorption decreases whilst chemical adsorption might be enhanced, evidenced by the better performance of ACs at 150 ℃. Chloride-impregnated ACs adsorption capability decreases as the water vapor concentration increases. The chloride content of chloride-impregnated ACs increased slightly, that results in increase of mercury removal efficiency. The performance of samples that were heat-treated deteriorates as the temperature of heat-treatment increases.