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采用TPR、BET、XRD、TG及反应性能评价等研究方法,考察了焙烧温度对甲烷催化部分氧化制合成气Ni/MgO-Al2O3催化剂结构和性能的影响。研究结果表明,随焙烧温度的升高, Ni/MgO-Al2O3 中的镍物种与载体作用逐渐增强,生成了NiAl2O4 尖晶石和NiMgO2 固熔体。虽然焙烧温度提高会使催化剂比表面降低,由于尖晶石结构的形成,其热稳定性会明显提高,将有利于抑制催化剂在反应过程中因烧结而失活的可能性。与低温焙烧的催化剂相比,高温焙烧的催化剂仍表现出良好催化反应性能,并具有相对较好的稳定性。高温焙烧的催化剂在反应过程中床层的热点温度相对较低,热点温度波动幅度也较小。低温和高温焙烧的Ni/MgO-Al2O3 催化剂在常压、1 083K、CH4 与O2 摩尔比为1. 8、空速2. 66×105h-1的反应条件下均具有良好的抗积炭性能。
The effects of calcination temperature on the structure and performance of Ni / MgO-Al2O3 catalyst for partial oxidation of methane to syngas were investigated by TPR, BET, XRD, TG and reaction performance evaluation. The results show that with the increase of the calcination temperature, the Ni species and NiO-MgO-Al 2 O 3 support gradually increase and the NiAl 2 O 4 spinel and NiMgO 2 solid solution are formed. Although the calcination temperature increases the specific surface area of the catalyst, the thermal stability of the spinel structure will be significantly improved due to the formation of the spinel structure, which will help to suppress the catalyst deactivation due to sintering during the reaction. Compared with low-temperature calcined catalysts, high-temperature calcined catalysts still show good catalytic activity and have relatively good stability. During the reaction, the hot spot temperature of the bed calcined at high temperature is relatively low, and the hot spot temperature fluctuates less. The Ni / MgO-Al2O3 catalyst calcined at low temperature and high temperature has good anti-carbon deposition performance under atmospheric pressure, 1.083K, CH4 and O2 molar ratio of 1.8, space velocity 2. 66 × 105h-1 reaction conditions.