焙烧气氛和孔结构对加氢脱金属催化剂性能的影响

Impacts of calcination atmosphere and pore structure on performance of hydrodemetallization catalysts

采用饱和浸渍法、在不同焙烧气氛(空气、氮气、水蒸气)下制备了三种加氢脱金属Mo-Ni催化剂,并考察了焙烧气氛对催化剂脱金属、脱硫和脱残碳的影响,研究结果表明:焙烧气氛对加氢脱金属反应的活性影响不大,而空气气氛下焙烧的催化剂表现出相对较高的加氢脱硫和脱残碳活性。进一步考察了氧化铝孔结构对催化剂加氢脱金属性能的影响,并结合数值模拟计算,发现最可几孔径为22 nm的催化剂更有利于加氢脱金属过程的反应-扩散平衡,从而表现出较高的加氢脱金属性能。

Three kinds of Mo-Ni hydrodemetallization(HDM)catalysts are prepared by an incipient wetness impregnation method with the varied calcination atmosphere,i.e.,air,nitrogen and water-steam,then their hydrogenation performances for residual oil are evaluated.It is found that these calcination atmospheres have a little impact on the activity of the hydrodemetalization reaction,while the catalyst roasted in the air atmosphere shows relatively high hydrodesulfurization and carbon residue removal activity.The impacts of the pore structures of alumina on the hydrodemetallization activity are further investigated by combining experiments and numerical simulations.The results show that the most probable pore size of 22 nm is favorable for the hydrodemetallization,because of the facilitated reaction-diffusion balance.