复合钙基吸收剂吸附烟气中汞的试验研究

将飞灰和CaO以4∶1(质量比)混合,在室温25℃下消化10min,在68℃下干燥40min,制得基础吸收剂,再添加5%的KMnO₄(或NaClO₂)和15%的水分,制成可吸附燃煤烟气汞的复合钙基吸收剂. 研究了KMnO₄/NaClO₂添加量,吸收剂中水分含量,温度,进口φ(O₂)、ρ(Hg0)、ρ(SO₂)和ρ(NO)等因素对复合钙基吸收剂吸附烟气汞的影响. 结果表明:随着KMnO₄、NaClO₂添加量从0增至5%,复合钙基吸收剂对烟气汞10min吸附量从131.75ng/g分别增至443.00和876.08ng/g；在KMnO₄(或NaClO₂)添加量为5%,水分含量为15%,温度为80℃,进口φ(O₂)为6%的条件下,模拟烟气进口ρ(Hg0)从18.0μg/m3增至86.4μg/m3时,复合钙基吸收剂对烟气汞的最大吸附量升至1203.33ng/g(或2391.63ng/g)；当进口ρ(SO₂)从1429mg/m3增至2286mg/m3时,KMnO₄(或NaClO₂)添加剂相对应的烟气汞最大吸附量降至421.50ng/g(或860.00ng/g)；当进口ρ(NO)从536mg/m3增至938mg/m3时,KMnO₄(或NaClO₂)添加剂相对应的烟气汞最大吸附量降至336.75ng/g(或776.38ng/g). 

Experimental Study on Mercury Absorbed from Flue Gas with Ca-Based Composite Sorbent

A Ca-based composite sorbent was developed to absorb mercury from coal flue gas. Fly ash and CaO with a mass ratio of 4∶1 were hydrated at 25℃ for 10minutes and were dried at 68℃ for 40minutes to make the basic sorbent. The basic sorbent was further tested with oxidants such as KMnO₄, NaClO_2and H₂O. During this process the resulting composite sorbent had 5% of KMnO₄/NaClO_2and 15% of water respectively. An experimental study was performed to investigate the effects of the dosage of oxidant (KMnO₄/NaClO₂), water content, temperature, φ(O₂), ρ(Hg0), ρ(SO₂) and ρ(NO) on the mercury capturing capacity of the Ca-based composite sorbent. The experimental results showed that when the addition of KMnO₄/NaClO₂increased from 0to 5%, the mercury absorption for 10minutes by the Ca-based composite sorbent increased from 131.75ng/g to 443.00ng/g and 876.08ng/g, respectively; under the condition of that the addition of KMnO₄/NaClO_2was 5%, water content was 15%, the temperature was 80℃ and φ(O₂) was 6%, when the ρ(Hg0) increased from 18.0μg/m3to 86.4μg/m3, the maximum adsorption of mercury increased to 1203.33ng/g with KMnO_4as the additive and 2391.63ng/g with NaClO_2as the additive; when the ρ(SO₂) increased from 1429mg/m3to 2286mg/m3, the maximum adsorption of mercury decreased to 421.50ng/g with KMnO_4and 860.00ng/g with NaClO₂; when the ρ(NO) increased from 536mg/m3to 938mg/m3, the maximum adsorption of mercury decreased to 336.75ng/g with KMnO_4as the additive and 776.38ng/g with NaClO_2as the additive.