Study On Hydrodesulfurization Performance Of Water-absorbent Resin Carbon-supported Ni₂P Catalyst

With the increasing gravification of crude oil,the conventional hydride-sulfurization catalyst system is facing challenges.Due to its ellipsoidal structure,Ni₂P can expose more active centers,showing hydrodesulfurization activity that is superior to that of traditional catalysts.Using a carbon material with tunable surface chemistry as a carrier can control the grain size of Ni₂P to obtain a high-performance catalyst.By introducing molecular sieves,the B acid center is added in the carrier to further reduce the particle size and improve the activity of the catalyst.In this thesis,resin material was selected as the precursor to prepare the catalyst.The carbon material was treated by ion exchange,nitric acid treatment and the introduction of molecular sieve into the carbon-based system.The Ni₂P catalyst was prepared by constant volume impregnation method and phosphatizing method of separating phosphorus source and nickel source,and the controllable adjustment of Ni₂P particle size was realized.The hydrodesulfurization（HDS）reaction of dibenzothi-ophene and 4,6-dimethyldiben-zothiophene as model compound（N-Decane）was evaluated in a high pressure fixed bed.The carrier and catalyst were characterized by SEM,ICP-OES,BET,Raman,FT-IR and XRD.By analyzing the data difference of catalyst conversion rate and reaction path,the effects of catalysts loaded with metal by different methods and treated with carbon materials on the reaction performance were compared.Based on the optimization of metal loading methods,the surface chemical properties of the support were adjusted,and the effects of different treatment methods on the particle size of the active phase were studied.Ni₂P/C-R-Y-6L catalyst was prepared by introducing molecular sieve into carbon and treated with nitric acid.The performance of Ni₂P/Al₂O₃ catalyst was compared with that of traditional oxide support.The results show that the catalyst activity prepared by adsorption method is much lower than that prepared by impregnation method.The activity of Ni₂P/C-R-6L catalysts after nitric acid treatment was 10%higher than that of untreated Ni₂P/C-R catalysts.The Ni₂P/C-R-Y-6L catalyst obtained by further introducing molecular sieve into carbon and then treated with nitric acid has rich pore structure,more uniform metal dispersion,smaller particle size and the highest hydrodesulfurization activity obtained after phosphating.At 340°C and 3MPa（H₂）,the conversion rate of DBT and 4,6-DMDBT reached 100%and 43%,respectively,and the conversion rate of Ni₂P/Al₂O₃was only 20%and 10%.The introduction of molecular sieve can increase the B acid center on the carbon surface and promote the transition of pre-hydrogenation path in hydrodesulfurization reaction.The combination of molecular sieve and modified carbon surface to promote the chemical properties of the active phase effectively improves the overall hydrodesulfurization activity of the catalyst.