The objective of this study is to explore the optimum composition of Y and ZSM-5 zeolites to develop novel catalysts for obtaining lower gasoline olefins content and higher propylene yield. Five composite zeolite cata...The objective of this study is to explore the optimum composition of Y and ZSM-5 zeolites to develop novel catalysts for obtaining lower gasoline olefins content and higher propylene yield. Five composite zeolite catalysts with varying Y zeolite/ZSM-5 zeolite ratios have been prepared in this work to investigate the synergy between the Y zeolite and ZSM-5 zeolite on the selectivity to protolytic cracking, β-scission, oligomerization, and hydrogen transfer reactions using a FCC naphtha feedstock at 480 ℃ in a confined fluidized bed reactor. Experimental results showed that the composite catalyst with a Y zeolite/ZSM-5 zeolite ratio of 1:4 had the highest protolytic cracking and β-scission ability, which was even higher than that of pure ZSM-5 catalyst. On the other hand, the catalyst with a Y zeolite/ZSM-5 zeolite ratio of 3:2 exhibited the strongest hydrogen transfer functionality while the pure Y zeolite based catalyst had the highest oligomerization ability. For all the catalysts tested, increasing conversion enhanced the selectivity to protolytic cracking and hydrogen transfer reactions but reduced the selectivity to β-scission reaction. However, no clear trend was identified for the selectivity to oligomerization when an increased conversion was experienced.展开更多
A study on catalytic dehydration of 4-hydroxy-3-hexanone(HH)to 4-hexen-3-one(HO)was carried out through conversion of HH over HZSM-5 zeolite catalyst in a fixed-bed reactor(FBR)operating under atmospheric pressure.The...A study on catalytic dehydration of 4-hydroxy-3-hexanone(HH)to 4-hexen-3-one(HO)was carried out through conversion of HH over HZSM-5 zeolite catalyst in a fixed-bed reactor(FBR)operating under atmospheric pressure.The test indicated a relatively high activity of the HZSM-5 zeolite capable of achieving a HH conversion of 99.2%and a HO yield of 83.5%.Catalyst deactivation could be prevented by increasing the reaction temperature by 10℃for every 20 h and adding 2.0%of piperidine in the feed.A catalyst stability test(for 100 h)in FBR showed that the catalyst was active even after 100 h of time-on-stream with HH conversion remaining at 99.2%and HO yield still reaching over 83.5%.Regeneration experiment showed that the regenerated catalyst demonstrated a catalytic performance comparable to the fresh one.展开更多
基金financial support from the National Key Technology R&D Program (2012BAE05B01) of China
文摘The objective of this study is to explore the optimum composition of Y and ZSM-5 zeolites to develop novel catalysts for obtaining lower gasoline olefins content and higher propylene yield. Five composite zeolite catalysts with varying Y zeolite/ZSM-5 zeolite ratios have been prepared in this work to investigate the synergy between the Y zeolite and ZSM-5 zeolite on the selectivity to protolytic cracking, β-scission, oligomerization, and hydrogen transfer reactions using a FCC naphtha feedstock at 480 ℃ in a confined fluidized bed reactor. Experimental results showed that the composite catalyst with a Y zeolite/ZSM-5 zeolite ratio of 1:4 had the highest protolytic cracking and β-scission ability, which was even higher than that of pure ZSM-5 catalyst. On the other hand, the catalyst with a Y zeolite/ZSM-5 zeolite ratio of 3:2 exhibited the strongest hydrogen transfer functionality while the pure Y zeolite based catalyst had the highest oligomerization ability. For all the catalysts tested, increasing conversion enhanced the selectivity to protolytic cracking and hydrogen transfer reactions but reduced the selectivity to β-scission reaction. However, no clear trend was identified for the selectivity to oligomerization when an increased conversion was experienced.
基金supported by the Science and Technology Planning Program of Tianjin(Project No.12ZXCXGX21900)
文摘A study on catalytic dehydration of 4-hydroxy-3-hexanone(HH)to 4-hexen-3-one(HO)was carried out through conversion of HH over HZSM-5 zeolite catalyst in a fixed-bed reactor(FBR)operating under atmospheric pressure.The test indicated a relatively high activity of the HZSM-5 zeolite capable of achieving a HH conversion of 99.2%and a HO yield of 83.5%.Catalyst deactivation could be prevented by increasing the reaction temperature by 10℃for every 20 h and adding 2.0%of piperidine in the feed.A catalyst stability test(for 100 h)in FBR showed that the catalyst was active even after 100 h of time-on-stream with HH conversion remaining at 99.2%and HO yield still reaching over 83.5%.Regeneration experiment showed that the regenerated catalyst demonstrated a catalytic performance comparable to the fresh one.
基金ACKNOWLEDGMENTS This work was supported by the National Nat- ural Science Foundation of China （No.51161140331） and the National Key Basic Program of China （No.2013CB228105）.
