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结合行星式球磨机,采用低温固相法制备Ni-Al_2O_3催化剂,考察了球磨时间对Ni-Al_2O_3催化剂晶相结构(XRD)、还原特征(H2-TPR)、孔道结构(BET)、粒径分布(PSD)、表面形貌(SEM)和浆态床CO甲烷化性能的影响.结果表明,球磨时间为60 min,催化剂(CT-60)平均粒径最小,为141 nm;比表面积最大,为329 m2/g.随球磨时间延长,Ni-Al_2O_3催化剂的甲烷化性能(CO转化率、CH_4选择性和CH_4收率)均先增加后减少.其中,球磨时间为60 min制备的催化剂(CT-60)甲烷化性能最佳,其CO转化率、CH_4选择性和CH_4收率分别达87.9%、8 6.8%和74.3%.结合催化剂表征可知,CT-60优异的性能与其具有较小的颗粒尺寸(141 nm)和较大的比表面积(329 m2·g-1)有很大的关联.即,催化剂颗粒尺寸越小,比表面积越大,其性能越好.
Ni-Al 2 O 3 catalyst was prepared by low-temperature solid-state reaction combined with planetary ball mill. The effect of milling time on the crystal structure, XRD, H2, TPR, PSD), surface morphology (SEM) and methanation performance of the slurry bed were investigated.The results showed that the average particle size of the catalyst (CT-60) was the smallest at 141 nm and the largest specific surface was 329 m2 / g. With the milling time prolonging, the methanation performance (CO conversion, CH4 selectivity and CH4 yield) of Ni-Al2 O3 catalyst first increased and then decreased, in which the catalyst prepared by ball milling for 60 min ) Methanation performance was the best, the CO conversion, CH_4 selectivity and CH_4 yield were 87.9%, 8 6.8% and 74.3% respectively. Combining the catalyst characterization shows that CT-60 excellent performance and its smaller particle size ( 141 nm) and the larger specific surface area (329 m2 · g-1) .That is, the smaller the catalyst particle size, the greater the specific surface area, the better the performance.