The addition of distillation residues to the FCC feedstock leads to increased vanadiumloading on catalyst and the problems in catalyst deactivation.The deactivation process is related tothe destructive attack on the z...The addition of distillation residues to the FCC feedstock leads to increased vanadiumloading on catalyst and the problems in catalyst deactivation.The deactivation process is related tothe destructive attack on the zeolite crystallite by V<sub>2</sub>O<sub>5</sub>.Formation of low melting pointV<sub>2</sub>O<sub>5</sub>-USY-Na<sub>2</sub>O phases accelerates the diffusion of vanadium through the catalyst.A proposedmechanism,based on accelerated dealumination,is shown in the paper.Comparative vanadiumtrapping performances have been tested for FCC catalysts and the crystalline ABO<sub>3</sub> as an effectivevanadium trap is demonstrated in laboratory tests.展开更多
The need for more active and hydrothermally stable fluid catalytic cracking（FCC）catalysts to combat the effect of metal contaminants has led to an increase in demand for rare earth oxides.Rare earth oxides enhance c...The need for more active and hydrothermally stable fluid catalytic cracking（FCC）catalysts to combat the effect of metal contaminants has led to an increase in demand for rare earth oxides.Rare earth oxides enhance catalyst activity and prevent the loss of acid sites during the FCC unit operation,especially when heavy residue with high metal content is used as feed.In this paper,a review was carried out to show the effects of rare earth elements on the structure,activity,and stability of FCC catalysts.Also,the use of rare earth elements as vanadium traps was analyzed in conjunction with the mechanism of catalyst deactivation by vanadium.The objective was to elucidate the interaction of vanadium species with the zeolite component of the FCC catalysts and the role of rare earth elements in countering the deleterious effects of vanadium on the FCC catalysts.展开更多
文摘The addition of distillation residues to the FCC feedstock leads to increased vanadiumloading on catalyst and the problems in catalyst deactivation.The deactivation process is related tothe destructive attack on the zeolite crystallite by V<sub>2</sub>O<sub>5</sub>.Formation of low melting pointV<sub>2</sub>O<sub>5</sub>-USY-Na<sub>2</sub>O phases accelerates the diffusion of vanadium through the catalyst.A proposedmechanism,based on accelerated dealumination,is shown in the paper.Comparative vanadiumtrapping performances have been tested for FCC catalysts and the crystalline ABO<sub>3</sub> as an effectivevanadium trap is demonstrated in laboratory tests.
基金Program supported by Chemicals R&D Division,Saudi Aramco
文摘The need for more active and hydrothermally stable fluid catalytic cracking（FCC）catalysts to combat the effect of metal contaminants has led to an increase in demand for rare earth oxides.Rare earth oxides enhance catalyst activity and prevent the loss of acid sites during the FCC unit operation,especially when heavy residue with high metal content is used as feed.In this paper,a review was carried out to show the effects of rare earth elements on the structure,activity,and stability of FCC catalysts.Also,the use of rare earth elements as vanadium traps was analyzed in conjunction with the mechanism of catalyst deactivation by vanadium.The objective was to elucidate the interaction of vanadium species with the zeolite component of the FCC catalysts and the role of rare earth elements in countering the deleterious effects of vanadium on the FCC catalysts.
