基于MCM-41的镍基甲烷化催化剂活性与稳定性

采用浸渍法分别以MCM-41，Al₂O₃和SiO₂ 为载体制备了不同镍负载量的甲烷化催化剂，并在连续流动固定床反应装置上对其甲烷化催化活性进行了评价。研究结果表明，与Ni/Al₂O₃和Ni/SiO₂相比，相同镍负载量的Ni/MCM-41催化剂具有更好的催化活性。同时研究了Ni含量对于Ni/MCM-41催化剂催化活性的影响，发现随着Ni含量的增加，CO转化率和CH₄收率逐渐升高，并且在Ni含量大于10%（质量分数）以后趋于稳定。在n（H₂）：n（CO）=3：1、反应压力1.5 MPa、反应温度350℃及质量空速12000 ml·h^-1·g^-1的反应条件下，10%Ni/MCM-41催化剂CH₄选择性达到94.9%，CO转化率接近100%。在100 h催化活性稳定性试验中，10%Ni/MCM-41催化活性无明显下降，表现出良好的催化活性稳定性。采用X射线衍射（XRD）、氮气物理吸附（BET）、热重分析（TG）及氢气程序升温还原（H₂-TPR）等技术手段对催化剂进行了表征，结果表明Ni颗粒大小是影响Ni/MCM-41催化剂催化活性的主要因素。

Activity and stability of nickel based MCM-41 methanation catalysts for production of synthetic natural gas

Nickel based catalysts with different nickel contents were prepared by the impregnation method with MCM-41, Al₂O₃ and SiO₂ as supports, and catalytic performance was studied in a fixed-bed reactor for the production of synthetic natural gas (SNG). Compared with the Ni/Al₂O₃ and Ni/SiO₂ catalysts, Ni/MCM-41 catalysts with the same nickel content of 10%(mass) showed better catalytic performance with high CO conversion of 100% and CH₄ yield of 94.9% at 350℃ under 1.5 MPa with 3:1 molar ratio of H₂ to CO and a weight hourly space velocity (WHSV) of 12000 ml·h^-1·g^-1. The effect of Ni loading on catalytic performance of Ni/MCM-41 catalysts was also investigated. Catalytic activity increased with increasing Ni loading and kept stable with Ni loading of above 10%(mass). 10%Ni/MCM-41 catalyst also exhibited excellent catalytic activity and stability in the catalytic stability test. The catalysts were characterized with X-ray diffraction (XRD), N₂ physisorption measurements, thermo gravimetric analysis (TG) and H₂ temperature-programmed reduction (H₂-TPR). Ni particle size could obviously affect the catalytic performance of Ni/MCM-41 catalysts. Ni/MCM-41 catalyst with 10%(mass) nickel content and appropriate nickel particles of 15.5 nm exhibited good catalytic performance with almost 100% CO conversion and 94.9% CH₄ yield.