环境化学
乔少华,李剑峰,陈杰,瞿赞,晏乃强,贾金平.零价汞在MnOx/α-Al2O3-氯气体系中的催化氧化[J].环境科学学报,2009,29(7):1475-1479
零价汞在MnOx/α-Al2O3-氯气体系中的催化氧化
- Catalytic oxidation of elemental mercury in flue gas over MnOx/α-Al2O3 with chlorine
- 基金项目:国家高技术研究发展计划(863)项目(No.2007AA06Z340)
- 乔少华
- 上海交通大学环境科学与工程学院, 上海 200240
- 李剑峰
- 上海交通大学环境科学与工程学院, 上海 200240
- 陈杰
- 上海交通大学环境科学与工程学院, 上海 200240
- 瞿赞
- 上海交通大学环境科学与工程学院, 上海 200240
- 晏乃强
- 上海交通大学环境科学与工程学院, 上海 200240
- 贾金平
- 上海交通大学环境科学与工程学院, 上海 200240
- 摘要:为强化烟气中零价汞向二价汞的转化,利用模拟含汞烟气研究了以MnOx/α-Al2O3作为催化剂、利用氯气作为氧化剂催化氧化零价汞的方法.着重考察了氯气浓度、温度、空速和SO2对催化氧化零价汞性能的影响,并与HCl作为氧化剂的结果进行了对比.同时,对催化剂进行表征,探讨了催化剂表面吸附态汞的形态.研究结果表明,Cl2较HCl更易活化且活性温度区间更广,在100~300℃范围内,Cl2体积分数为2.0×10-6时的催化氧化效率即可达80%以上;在1.6×104~6.4×104h-1空速范围内,零价汞氧化率保持在90%以上,空速继续提高到1.92×105h-1时,零价汞氧化率呈现线性下降趋势;烟气中的SO2与Cl2反应会消耗Cl2,Cl2体积分数低时对催化氧化反应抑制作用显著,但Cl2体积分数增至5.0×10-6时对催化氧化反应的抑制效果较弱,仅为10%左右.
- Abstract:In order to enhance the oxidation of elemental mercury to oxidized mercury,which is readily captured by flue gas desulfurization(FGD),MnOx/α-Al2O3 was employed as the catalyst to convert Hg0 to Hg2+ in the presence of chlorine gas.The main factors that affect the catalytic performance were investigated,such as the concentration of Cl2,temperature,space velocity and SO2.The results revealed that Cl2 was more reactive than HCl over a wider temperature range,and more than 80% of Hg0 oxidation efficiency was achieved with a 2.0×10-6 volume fraction of Cl2 between 100~300 ℃.The oxidation efficiency remained over 90% while the space velocity increased from 1.6×104 h-1 to 6.4×104 h-1.The Hg0 oxidation efficiency was inhibited by SO2 when the volume fraction of Cl2 was less than 2.0×10-6,but the inhibitory effect was only 10% when Cl2 was above 5.0×10-6.
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