Study On Suifur Removal From Diesel With Activated Carbon Based Adsorbent

With the more and more stringent sulfur standards, Diesel desulfurizationtechnology is becoming more and more great significance. Nowadays, the traditionhydrodesulfurization（HDS）needs harsh conditions with high operating costs andremoval of dibenzothiophene（DBT）and its derivatives are more difficult, besides,the loss of octane is big. However, adsorptive desulfurization is an effective methodof removing sulfur from diesel, which simple operation, low investment, small lossof octane. Therefore, adsorptive desulfurization has potential application prospect.In this paper, activated carbon based adsorbent was pretreated with differentoxidation modification, redox modification, ultrasonic wave modification, plasmamodification were adopted to prepare catalysts and investigated the effect for modeloil adsorption desulfurization. The static adsorption method was adopted to evaluatethe desulfurization performance of sorbents to select the best preparation conditionsand appropriate desulfurizer, at last the regeneration of desulfurizing was researched.The catalyst was characterized and evaluated by N2adsorption, SEM, XRD, FT-IR,H2-TPR and gaschromatography.Firstly, activated carbon was pretreated with deionized water and HCI in orderto ash removal, and then oxided by different oxidants and select the best carrieractivated carbon base, at last equal volume impregnation were adopted to preparecatalysts loaded different active components for desulfurization. The experimentalresults show that: the specific surface area smooth and total pore volume increasedafter ash removal with deionized water and HCl. Compared to deionized watertreatment, nitric acid oxidation modification makes the increase ofoxygen-containing acidic groups on AC surface and enhance the removal of sulfur compounds.Using AC treated with deionized water and nitric acid as carrier loadedZn(NO3)2, Fe(NO3)3, Cu(NO3)2, Co(NO3)2, Ni(NO3)2were prepared byimpregnation method to investigate its desulfurization performance for thiophene inmodel diesel fuel. The result shown that, among them, activated carbons loaded withCo(NO3)2showed the best desulfurization rate and the optimum preparationconditions for the AC were obtained as follows: Co loading amounts20%(w),reaction time12h, under such conditions sulfur removal rate reached to88.6%usingthe adsorbents.With90oC nitric acid modified activated carbon as the carrier, loaded cerium asadsorbent was prepared using Ultrasonic impregnation and ordinary method toinvestigate its desulfurization performance for thiophene (T) in model diesel. Theresult showed: Ce loading amounts10%(w) under Ultrasonic impregnation has thebest sulfur removal rate reached to95%. Finally, the adsorption isotherm of Ce/ACon the adsorption removal of thiophene was discussed.Activated carbon supported Cu(NO3)2and Pd(NO3)2two components basedcatalysts were prepared by impregnation method. Results indicate that Pd(II) andCu(I) both can happen π ligand adsorption with thiophene, which leaded toPd-Cu/AC-KOH adsorbent the highest desulfurization rate when the mole ratio ofCu/Pd/OH is1/0.5/1. Finally, the Pd-Cu/AC-KOH adsorption removal mechanismof thiophene were discussed.