Catalytic Activity Of Spent FCC Catalyst-supported Nickel In The Hydrogenation Of Diesel Oil Or Turpentine And Its Characterization

As crude oil in the world is getting heavier and worse,the quality of FCC raw material is getting worse,which causing the domestic FCC catalysts for one-time use,and the amount of waste catalysts increased year by year.The ways of spent FCC catalysts processing and recycling more economy effectively have always been industry's attention.In this paper,spent FCC catalyst was regenerated and used to prepare supported catalyst,which was applied for hydrogenation of diesel oil and turpentine,in order to improve diesel oxidation stability,obtain pinane of high cis-trans ratio and improve the utilization of spent FCC catalyst.The main research contents are as follows:Spent FCC catalyst-supported nickel catalyst was prepared by isovolumetric impregnation,with spent FCC catalyst as carrier,and its catalytic activity of hydrogenation was studied.On the conditions of temperature 533 K,pressure 3 MPa,stirring speed 360 r·min-1 and reaction time 3 h,the effect of different catalyst on catalytic hydrogenation of FCC diesel oil was studied over self-made Pd/C,Raney nickel and spent FCC catalyst loaded with different nickel content.The results showed that,spent FCC catalyst loaded with nickel content of 5 wt%had a better catalytic activity than Raney nickel and Pd/C on desulfurization.As the effects of reaction temperature,pressure and time of FCC diesel oil hydrogenation were investigated,the optimum reaction condition was obtained as reaction temperature 513 K,reaction time 1 h and pressure 3 MPa.The effect of preparation of catalyst on turpentine hydrogenation was investigated by single-factor experimental,including nickel loading,reduction temperature,calcination temperature and other factors,using orthogonal experiment to study the effects of various factors on conversion of pinene and cis-trans ratio of pinane in turpentine hydrogenation.The optimum preparation conditions of the catalyst were obtained as followed:nickel content 20 wt%,calcination temperature 823 K,calcination time 3 h,reduction temperature 673 K,reduction time 2.5 h.The hydrogenation products of turpentine over spent FCC catalyst supported nickel catalyst in 1.5 h were analyzed and identified by GC-MS.The major compounds were ?-pinene,trans-pinane,cis-pinane,p-cymene and so on.According to the optimum preparation conditions,verification experiment of turpentine hydrogenation was examined.The results showed that the optimum reaction condition of turpentine hydrogenation were as follows:reaction temperature 383 K,reaction pressure 2 MPa,stirring speed 450 r·min-1,catalyst amount 4.5%according to the quantity of turpentine and reaction time 2 h,the conversion of pinene was larger than 99.9%and cis-trans ratio of pinane was more than 16:1.The structure and properties of fresh FCC catalyst,spent FCC catalyst and supported nickel catalysts were characterized by SEM-EDS,nitrogen adsorption-desorption,XRD,FT-IR,TG-DTA,H2-TPR and NH3-TPD.The results showed that fresh FCC catalysts were spherical particles with specific surface area 241.012 m2·g-1,spent FCC catalysts were irregularly shaped particles with specific surface area of 96.124 m2·g-1,having some salient feature and containing Ni and V.Nickel grain loaded on FCC catalyst was distributed uniformly on the carrier,and the surface areas of fresh FCC catalyst supported-nickel catalyst,spent FCC catalyst supported-nickel catalyst and deactivated catalyst were 205.395 m2·g-1,91.332 m2·g-1 and 66.133 m2·g-1 respectively.XRD and FT-IR test results showed that the structure of spent FCC catalyst was damaged.XRD patterns showed that,diffraction peak intensity of NiO over fresh FCC catalyst supported-nickel catalyst was higher than that of spent FCC catalyst at the same reduction temperature,while loading the same content of nickel.At the stage of decomposition of nickel nitrate,the TG curve of fresh FCC catalyst supported catalyst was changed more gentlely than that of spent FCC catalyst supported catalyst.H2-TPR spectra showed that,the reduction temperature using fresh FCC catalyst as carrier was higher that with spent FCC catalyst as carrier,and the reduction peak was wide.TG-DTA and H2-TPR showed that the interaction between fresh FCC catalyst and nickel was stronger than that between spent FCCcatalyst and active component.NH3-TPD results showed that fresh FCC catalyst exhibited both weak acid sites and strong acid sites,as spent FCC catalyst was distributed weak acid sites only and the number of acid sites decreased.After loading nickel,the acid strenth of catalyst increased.EDS results showed that nickel content on deactivated catalyst was decreased by 2.72%.