Preparation Of Slurry Impregnated NiMo/C-HY Catalyst And Its Reaction Performance In Hydrodesulfurization Of DBT And 4,6-DMDBT

With the shortage of oil resources and increasingly serious environmental pollution,the development and application of high activity hydrodesulfurization catalyst has become particularly important.When the carbon material with adjustable pore structure is used as the support of hydrodesulfurization catalyst,the weak interaction between the support and metal can be used to obtain class II nimos active sites with more corner active sites.When molecular sieve is added to the carbon support,B acid center can be introduced into the catalyst to further improve the reaction activity of the catalyst.In this paper,the superabsorbent materials were selected to adsorb the gel and grout of the molecular sieve in different ways.The carbon molecular sieve materials were prepared by ion exchange and carbonization.The impregnated carrier was impregnated by the same volume method,and a series of NiMo/C-HY hydrodesulfurization catalysts were prepared by calcination in inert atmosphere,with a concentration of 1000mg/L DBT.200 mg / L 4,6-dmdbt was used as a model compound(dodecane as solvent)to evaluate the hydrodesulfurization reaction of NiMo / c-hy catalyst.In order to explore the synergistic principle of carbon and molecular sieve in hydrodesulfurization catalyst,the structure and physicochemical properties of the catalyst were characterized by XRD,bet,H2-TPR,SEM,TEM and XPS.The effects of molecular sieve introduction on the reaction performance of the catalyst were compared through the changes of conversion and selectivity of reaction path.The metal content was adjusted on the basis of the optimized NiMo / c-hy-s catalyst,The combined promotion mechanism of carbon and molecular sieve under high metal content was investigated.NiMo / c-hy-2s catalyst was prepared by increasing the concentration of molecular sieve slurry,and its hydrodesulfurization performance was compared with that of traditional NiMo / Al2O3 catalyst.The results show that the NiMo / c-hy-s catalyst obtained by adsorption of molecular sieve slurry with resin material,ion exchange and calcination has rich pore structure,uniform metal dispersion and high crystallinity on the support.The conversion of DBT and 4,6-dmdbt reaches99.47% and 94.58% at 320 ℃.On NiMo / c-hy-s catalyst,the introduction of molecular sieve will promote the conversion of pre hydrogenation path in hydrodesulfurization reaction,and improve the hydrodesulfurization activity of the catalyst by improving the hydrogenation performance of the catalyst.Compared with the catalyst without molecular sieve,the conversion of DBT increased by 30% and that of 4,6-dmdbt increased by 5%.The synergistic effect of slurry impregnated carbon molecular sieve is reflected in: the introduction of molecular sieve provides rich pore structure for carbon carrier.Carbon carrier makes use of its weak interaction with metal and these rich pore structures to make high content metal better dispersed on the carrier surface and easier to be reduced.When the high content of metal is completely dispersed,more active centers with high stacking layers will be formed on the carbon carrier.The combined promotion of the three and the promotion form a closed loop,so that the catalyst has higher hydrogenation performance.