CaO中高温脱除HCl的特性试验研究

Experimental study on HCl removal characteristics over CaO at moderate and high temperature

为在中高温下脱除垃圾焚烧烟气中的HCl，在不同初始HCl浓度（450～1500 mg/m3）、反应温度（300～700℃）以及吸附剂粒径（0．15～2 mm）条件下对CaO脱氯特性进行了试验，并采用扫描电子显微镜（SEM）和能谱仪（EDS）对反应过程中的CaO颗粒进行分析．试验结果表明：随初始HCl浓度的减小，CaO对HCl的吸附能力升高，当HCl浓度为750 mg/m3时CaO转化率最高（12．20％），浓度继续减小，CaO转化率不变；随着反应温度升高，CaO转化率呈现先上升后下降的趋势，并在400℃达到峰值；CaO对HCl的吸附能力随粒径的减小而增加，当粒径范围从1～2 mm减小到0．150～0．355 mm时，CaO转化率提高7．78％．由SEM和EDS可见，未反应的CaO表面疏松多孔，随着与HCl反应的进行，颗粒结构变得致密且表面逐渐被反应产物CaCl2所覆盖，当颗粒表面完全被产物层包裹时吸附剂失效．

In order to remove HCl from waste incineration gas at moderate and high temperature,ex-periments of CaO dechlorination characteristics were carried out under different conditions,including HCl initial concentrations （450 to 1 500 mg/m3 ）,reaction temperatures （300 to 700℃）,and parti-cle sizes （0.15 to 2 mm）,and CaO characteristics in the reaction process were analyzed by scanning electronic microscopy （SEM） and energy dispersive spectrometer （EDS ）.Experimental results show that CaO dechlorination capability increases with the decrease of HCl initial concentration,and the CaO conversion rate achieves 12.20%at 750 mg/m3 of HCl concentration,while the conversion rate keeps unchanged with further decrease of HCl concentration.With the increase of the reaction temperature,the CaO conversion rate shows an increasing trend first and then a decreasing trend, and reaches the peak at 400 ℃.The CaO dechlorination capability increases with the reducing of particle size,and the CaO conversion rate improves about 7.78% when the particle size changes from the range of 1 to 2 mm to the range of 0.150 to 0.355 mm.It is shown from SEM and EDS that the surface of unreacted CaO is porous,then the particle structure clusters and is covered with CaCl2 when the reaction is carried out.The adsorbents lose their effectiveness while the particle sur-face is wrapped with reaction product.