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本文研究了前驱体MoO_3的负载量、浸渍温度和焙烧温度等制备条件对Mo S2/Al_2O_3耐硫甲烷化催化剂性能的影响,并通过XRD和H2-TPR表征了催化剂的物相和还原性能。结果表明,随着负载量增加,MoO_3与Al_2O_3间的相互作用增强,Al2(Mo O4)3相增多,导致催化剂更难被还原硫化,MoO_3还原温度升高。浸渍温度对CO转化率和CH4选择性有一定的影响,浸渍温度为70℃时,MoO_3的生成增多,且还原温度最低,CO转化率较高,而CH4选择性和CO_2选择性变化不大。随着焙烧温度升高,CO转化率先升高后降低,对CH4和CO_2选择性影响不大,其中以450℃焙烧的CO转化率最高,600℃焙烧的CO转化率最低。当焙烧温度在400~450℃时,Al2(Mo O4)3和Mo4O11的特征峰基本上消失,能够完全生成MoO_3,且结晶度较好。因此,合适的焙烧温度为400~450℃。
The effects of preparation conditions, such as the loading of MoO 3, impregnation temperature and calcination temperature, on the performance of Mo S2 / Al 2 O 3 sulfur-tolerant methanation catalysts were investigated. The phase and reduction performance of the catalysts were characterized by XRD and H2-TPR. The results show that the interaction between MoO 3 and Al 2 O 3 increases and the amount of Al 2 (Mo O 4) 3 phase increases with the increase of loading, which makes the catalyst more difficult to be reduced and sulfided, and the temperature of MoO 3 reduction increases. The impregnation temperature has some influence on the CO conversion and CH4 selectivity. When the immersion temperature is 70 ℃, the formation of MoO 3 increases, the reduction temperature is the lowest and the conversion of CO is higher. However, the CH 4 selectivity and CO 2 selectivity do not change much. With the increase of calcination temperature, the conversion of CO increased first and then decreased, which had little effect on the selectivity of CH4 and CO_2. The CO conversion at 450 ℃ was the highest and the CO conversion at 600 ℃ was the lowest. When the calcination temperature is in the range of 400-450 ℃, the characteristic peaks of Al 2 (Mo O 4) 3 and Mo 4 O 11 disappear basically, MoO 3 can be completely formed and the crystallinity is good. Therefore, a suitable calcination temperature is 400 to 450 ° C.