The Forming Factors Of Physicochemical Properties Of Aluminum Based Supports And Their Effect On The Catalytic Hydrogenation

The support is an important component of the catalyst which not only plays an important role in supporting the active components and improving the dispersion of active components,but also provides a place for reactions.Therefore,the properties of support have an important impact on the activity of catalyst.This paper focus on the effects of precursor synthesis method on the properties of?-Al₂O₃,the influences of TiO₂ content on the properties of TiO₂-Al₂O₃ and SiO₂ content on the properties of SiO₂-Al₂O₃.Different supporties are used to prepare Ni-Mo catalysts for hydrodesuifurization and hydrodenitrification activity evaluation.The experimental resuls show that the precursor synthesis method has influence on the properties of?-Al₂O₃.The pore structure and surface morphology of the samples with different synthesis method has different characteristics.And the crystallinity of the samples is also different.Pseudoboehmite produced by Carbonization Method and Neutralization Method has high crystallinity,but low purity of crystalline phase.Sample produced by Hydrothermal Method has the highest amount of acids,and produced by Alkoxide Hydrolysisi Method is least.Meanwhile Pseudoboehmite produced by acid method has highest proportion of strong acid.The properties of TiO₂-Al₂O₃ supports are different with the change of TiO₂content.By the increasing of TiO₂ content,the pore volume and pore size are decreasing and the thermal stability is improved.By the increasing of calcination temperature,the specific surface area decreases gradually and the pore volum increases and then decreases.TiO₂-Al₂O₃ supports only have Lewis acid center.By the increasing of TiO₂ content,the total acid amount decreases and the amount of weak acid increases.The porous structure of SiO₂-Al₂O₃ supports prepared by sol-gel method is improved.By the increasing of SiO₂ content,the specific surface area of samples firstly increases and then decreases.Meanwhile,the pore volum of the samples increases,and have more uniform element distribution.SiO₂-Al₂O₃ supports have both Lewis acid center and Bronsted acid center.By the increasing of SiO₂ content,the total acid amount increases first and then decreases.When the content of SiO₂ is 55%,the support has more-medium strong acid and fewer weak acid.The experimental resuls show that the pore size of catalysts that prepared by different supports concentrated distribution between 5-10nm.And those catalysts have appropriate amount of acid,good dispersion and weak interaction between the support.Because of those properties the catalysts have an excellent on hydrodesuifurization and hydrodenitrification.