The vanadium species were contaminated on FCC catalysts by using the Mitchell method. After the hydrothermal deactivation of the FCC catalysts, the cracking reaction was performed on these catalyst samples. The test r...The vanadium species were contaminated on FCC catalysts by using the Mitchell method. After the hydrothermal deactivation of the FCC catalysts, the cracking reaction was performed on these catalyst samples. The test results revealed that the conversion of feedstock and the gasoline yield obtained over the FCC catalysts with vanadium trapping components were obviously higher than those without addition of vanadium trapping components. The results also showed that the dry gas and coke selectivity on the FCC catalysts containing vanadium trapping components was improved. The X-Ray diffraction results proved that the zeolite crystal structure was well protected by the vanadium trapping components during its hydrothermal deactivation step. The results of SEM-EDX mapping disclosed that the vanadium was enriched on the vanadium trapping components which verified the positive function of vanadium trapping components.展开更多
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
基金supported by the National Basic Research Development Program "973" Project of China(2010CB732301)the SINOPEC Research and Development Program(No.112034)
文摘The vanadium species were contaminated on FCC catalysts by using the Mitchell method. After the hydrothermal deactivation of the FCC catalysts, the cracking reaction was performed on these catalyst samples. The test results revealed that the conversion of feedstock and the gasoline yield obtained over the FCC catalysts with vanadium trapping components were obviously higher than those without addition of vanadium trapping components. The results also showed that the dry gas and coke selectivity on the FCC catalysts containing vanadium trapping components was improved. The X-Ray diffraction results proved that the zeolite crystal structure was well protected by the vanadium trapping components during its hydrothermal deactivation step. The results of SEM-EDX mapping disclosed that the vanadium was enriched on the vanadium trapping components which verified the positive function of vanadium trapping components.
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.
