水泥熟料对模拟烟气中SO2和HCl的脱除特性

干法水泥窑协同处置城市生活垃圾,因其具有反应温度高、改造成本低、综合处理效果好、无二次污染等优势,得到世界各国普遍重视。利用固定床吸附实验装置,在700~1000℃温度下研究了水泥熟料对模拟烟气SO₂和HCl脱除特性影响,结合吸附剂及其吸附产物的理化特性初步分析了SO₂和HCl脱除机制。结果表明:1)在700~1000℃下,SO₂和HCl单独存在时,水泥熟料对SO₂脱除效率随着温度升高迅速提高,其最大SO₂单位吸附量可达到4.9 mg/g,与此相反,水泥熟料对HCl脱除效率则随着温度的升高而不断降低,当温度由700℃升高到1000℃时,HCl单位吸附量由8.40 mg/g降低至4.8 mg/g; SO₂或HCl的初始吸附速率由其组分浓度决定,熟料对HCl的吸附速率显著高于其对SO₂吸附速率。2)SO₂和HCl同时存在时,在相同吸附温度下,水泥熟料脱除HCl性能稍有降低,但总体影响不大;与此同时,HCl能够显著增强水泥熟料对SO₂的脱除能力和吸附反应速率,700,1000℃下,SO₂单位吸附量由1.8,4.9 mg/g分别提高到4.5,7.8 mg/g。水泥熟料及反应产物中Cl-迁移性是造成上述结果的主要原因。该研究结果为利用干法水泥熟料吸附城市生活垃圾焚烧烟气新协同处置工艺的工业应用提供了参考。

REMOVAL OF SO2 AND HCl FROM SIMULATED FLUE GAS BY CEMENT CLINKER

The co-processing of municipal solid waste(MSW) with dry cement kiln has been paid attention all over the world because of its advantages such as high reaction temperature, low renovation cost, good comprehensive treatment performance and no secondary pollution. The removal characteristics of SO₂ and HCl by cement clinker in simulated flue gas was investigated at 700~1000 ℃ in a fixed-bed experimental reactor. The adsorption mechanism of SO₂ and HCl was discussed on the basis of physiochemical properties of original and spent cement clinker samples. The results indicated that the removal efficiency of SO₂ by cement clinker increased rapidly as the reaction temperature increased from 700 ℃ to 1000 ℃, and the maximum unit adsorption capacity of SO₂ reached 4.9 mg/g while only SO₂ was present in simulated flue gas. The opposite was that the removal efficiency of HCl by cement clinker decreased as reaction temperature increased from 700 ℃ to 1000 ℃, and the corresponding unit adsorption capacity of HCl decreased from 8.40 mg/g to 4.8 mg/g while only HCl was present in the simulated flue gas. The initial adsorption rates of SO₂ or HCl were determined by its concentration, and the adsorption rate of HCl was significantly larger than that of SO₂. When SO₂ and HCl were present in simulated flue gas, the removal performance of HCl by cement clinker decreased slightly, but existing HCl could significantly promote the SO₂ removal performance and its adsorption reaction rate, and resulting in the unit adsorption capacity of SO₂ at 700 ℃ and 1000 ℃ increased from 1.8 mg/g and 4.9 mg/g to 4.5 mg/g and 7.8 mg/g, respectively. The main reason of above results was the migration of chloride ions in spent cement clinker. These results provide a reference for the industrial application of a new co-processing technology using dry cement clinker to treat municipal solid waste incineration flue gas.