Study On The Reactivation Of Spent FCC Catalyst

FCC catalyst whose active component is zeolite,is widely used in petroleum refining industry.After its long time used,the properties of activity and selectivity of FCC catalyst will be degradated because of heavy metal pollution,such as Ni,V.Therefore,FCC catalyst must be discharged as spent catalyst.However,the waste FCC catalyst which is dealt with as a solid waste,will not only cause a waste of resources,and also contaminate soil and groundwater due to the heavy metals.In this paper,the spent FCC catalyst was used as raw material for the purpose of recovering the properties of FCC catalyst by using hydrochloric acid removing of metal in channel at the suitable conditions.Furthermore,we investigated the effects of single or composite impregnated of rare earth and phosphorus on FCC catalytic cracking after the resurrection.And solid fluorescence,XRD,laser granularity analysis and BET were used for this study to investigate the influence of acid leaching conditions,the amount of phosphorus and rare earth on the FCC catalyst.Using fixed fluidized bed evaluated the performance of the spent FCC catalyst before and after modification.The followings are the main research contents and conclusions:(1)During the process of hydrochloric acid dipping with the spent FCC catalyst,the effects of the concentration of the hydrochloric acid,reaction temperature,soaking time and ratio of liquid on the microreactor activity and mechanical strength of the FCC catalyst were investigated.The optimal processing condition for the concentration of hydrochloric acid is C0 mol/L,for ratio of solid to liquid is N at the reaction temperature of T0 ? and the speed of 250 r/min under stirring for t0 hours.(2)After the spent FCC catalyst treated with hydrochloric acid under the optimal conditions.The XRD analysis indicated that zeolite was destroyed before and after impregnation.BET,catalyst specific surface,pore volume results indicated that the spent FCC catalyst was partially recovered;The micro-activity evaluation instrument for automatically measuring results indicated that micro-activity of the FCC catalyst increased 6 units after resurrection.The Catalyst abrasion tester results indicated that abrasion index of 2.61 did not reached the standard of cracking agent.(3)The results indicated that increasing of rare earth or phosphorus can't destroy the zeolite of the spent FCC catalyst treated with hydrochloric acid;The cracking performance of cracking catalyst increased after the resurrection;The increasing degree of activity after loading rare earth was higher than that of phosphorus loading;with the increase of phosphorus content after the resurrection of the FCC catalyst the abrasion index was reduced and the mechanical strength was increased.(4)The acid treated Changling refinery two kinds of spent FCC catalyst with rare earth and phosphorus modification,cracking activity increased,at the same time,the mechanical strength is improved.Compared with the original balance agent,product distribution has changed.