KCl对Cu-K-La/γ-Al2O3催化剂上HCl氧化反应性能的影响

摘要

Cu-K-La/γ-Al2O3 catalysts prepared by the incipient wetness impregnation for the catalytic oxida-tion of HCl to Cl2 at atmospheric pressure were investigated for the effect of KCl on the catalyst performance. Cu-K-La/γ-Al2O3 catalyst with 5 wt%KCl loading showed good activity and stability due to the promotion by KCl. It gave good activity over a wide range of space velocity of the feed gas and conversion of HCl above 85%, and it was nearly unchanged in activity after 100 h reaction at the conditions of 0.1 MPa, 360 °C, space velocity of 450 L/(kg-cat·h), and HCl/O2 molar ratio=2:1. X-ray diffraction results indicated that Cu, K, and La species were highly dispersed on the surface of theγ-Al2O3 support. H2 temperature-programmed reduction results indicated that the addition of KCl favored the reduction of Cu2+to Cu+and improved the activity of the active sites of Cu2+species for HCl oxidation.%采用等体积浸渍法制备了Cu-K-La/γ-Al2O3催化剂,考察了KCl对该催化剂催化HCl氧化制Cl2反应性能的影响.当KCl的负载量为5 wt%时, Cu-K-La/γ-Al2O3催化剂表现出较好的催化活性和稳定性,可在较大的原料气空速变化范围内使用.在0.1 MPa,360°C,空速450 L/(kg-cat·h)和HCl/O2摩尔比为2：1的反应条件下, Cu-K-La/γ-Al2O3催化剂上HCl转化率在100 h内保持85%以上.表征结果表明, Cu, K和La物种均高度分散于γ-Al2O3载体表面；一定量KCl的加入可降低Cu2+→ Cu+的还原温度,从而提高Cu2+活性中心的催化活性.