烟气中的CO_2对CaO吸附痕量硒元素的影响  

Effect of CO_2 on trace selenium adsorption by CaO from flue gas

作　　者：李玉忠[1] 佟会玲[1] 李彦[1] 禚玉群[1] 徐旭常[1] 

机构地区：[1]清华大学热能工程系热科学与动力工程教育部重点实验室,北京100084

出　　处：《清华大学学报（自然科学版）》2007年第5期699-702,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家"九七三"重点基础研究项目(2006CB200301)

摘　　要：在700℃左右的中温范围，CaO能够通过化学吸附作用脱除燃煤烟气中的有毒痕量元素——硒（存在形式为SeO2）。为探索烟气中的CO2对CaO吸附硒能力的影响，利用热重分析仪（TGA）进行吸附反应试验，通过CaO样品质量变化确定反应速率，并利用原子发射光谱（ICP-AES）确定CaO的硒吸附量。试验发现：CaO吸附SeO2的能力大于其吸附CO2的能力，SeO2能够置换被CaO吸附的CO2，进而与CaO结合；当存在高浓度的CO2时，痕量的SeO2气体仍然可以被CaO吸附；在700760℃范围内，由于CO2竞争作用的影响，CaO的固硒能力降低12％～35％；CO2的竞争影响随温度的升高而减小。Selenium, a trace element pollutant from coal combustion in the form of SeO2 in the flue gas, can be chemically absorbed by CaO at moderate temperatures of about 700℃. A thermo-gravimetric analysis （TGA） was used to study the effect of CO2 on selenium adsorption. The reaction rates were based on the sample weight changes. The selenium content in the post-sorption sample was determined using inductively coupled plasma-atomic emission spectrometry （ICP-AES）. The results show that CaO absorbs more SeO2 than CO2 and SeO2 can replace the CO2 already absorbed by the CaO. Therefore, trace SeO2 gas can be absorbed by CaO even when high concentrations of CO2 are present. Between 700 ℃ and 760 ℃, the SeO2 adsorption rate by CaO decreases by 12% to 35% because of the CO2 competition. The competition effect of CO2 decreases with increasing temperature.

关 键 词：二氧化碳 痕量元素 中温脱硫 二氧化硒 

分 类 号：X701.7[环境科学与工程—环境工程]