Active sites of Fluid catalytic cracking (FCC) catalyst are poisoned during operation in the FCC reactor due to causes including feedstock contaminant metals deposition. This leads to activity, selectivity and increas...Active sites of Fluid catalytic cracking (FCC) catalyst are poisoned during operation in the FCC reactor due to causes including feedstock contaminant metals deposition. This leads to activity, selectivity and increasing coking problems, thereby raising concern to the refiner. This work investigated effect of nickel coexisting with vanadium in the FCC feedstock on the standard FCC catalyst during cracking process, in which destruction of active sites occurs as a result of the metals deposition. Laboratory simulated equilibrium catalysts (E-cats) were studied by XRD, FTIR spectroscopy, N-2 adsorption, solid state MAS-NMR, SEM and H-2-TPR. Results revealed that vanadium, above a certain concentration in the catalyst, under hydrothermal conditions, is highly detrimental to the catalyst's structure and activity. Conversely, nickel hardly affects the catalyst structure, but its co-presence in the catalyst reduces destructive effects of vanadium. The mechanism of nickel inhibition of vanadium poisoning of the catalyst is discussed. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
This work investigates the evolution of structure and mechanical performance of metallic glasses（MGs）under a proposed rapid forming approach. Through the unique ultrasonic-assisted micro injection method, micro MGs ...This work investigates the evolution of structure and mechanical performance of metallic glasses（MGs）under a proposed rapid forming approach. Through the unique ultrasonic-assisted micro injection method, micro MGs parts with fine dimensional accuracy were successfully fabricated. The temperature during the micro injection is higher than the glass transition temperature and lower than the crystallization temperature. Differential scanning calorimeter curve and X-ray diffraction pattern show that the MGs micro parts keep the amorphous nature after the ultrasonic-assisted micro injection. Our results propose a novel route for the fast forming of MGs and have promising applications in the rapid fabrication of micro scale products and devices.展开更多
基金financially supported by the Joint Funds of the National Natural Science Foundation of ChinaChina National Petroleum Corporation(U1362202)+4 种基金National Natural Science Foundation of China(21206195)the Fundamental Research Funds for the Central Universities(14CX02050A,14CX02123A)Shandong Provincial Natural Science Foundation(ZR2012BM014)the project sponsored by Scientific Research Foundation for Returned Overseas Chinese Scholarthe support from Chinese Government under the Chinese scholarship scheme for international students
文摘Active sites of Fluid catalytic cracking (FCC) catalyst are poisoned during operation in the FCC reactor due to causes including feedstock contaminant metals deposition. This leads to activity, selectivity and increasing coking problems, thereby raising concern to the refiner. This work investigated effect of nickel coexisting with vanadium in the FCC feedstock on the standard FCC catalyst during cracking process, in which destruction of active sites occurs as a result of the metals deposition. Laboratory simulated equilibrium catalysts (E-cats) were studied by XRD, FTIR spectroscopy, N-2 adsorption, solid state MAS-NMR, SEM and H-2-TPR. Results revealed that vanadium, above a certain concentration in the catalyst, under hydrothermal conditions, is highly detrimental to the catalyst's structure and activity. Conversely, nickel hardly affects the catalyst structure, but its co-presence in the catalyst reduces destructive effects of vanadium. The mechanism of nickel inhibition of vanadium poisoning of the catalyst is discussed. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金supported by the National Natural Science Foundation of China (Nos. 51605304, 51575360, 51375315 and 51405306)the China Postdoctoral Science Foundation (No. 2016M601423)+2 种基金the Ph.D. Start-up Fund of Natural Science Foundation of Guangdong Province (Nos. 2016A030310036 and 2016A030310043)the Major Science and Technology Project of Guangdong Province (No. 2014B010131006)the Science and Technology Innovation Commission of Shenzhen (Nos. JCYJ20150525092941026, JCYJ20150625102923775, JCYJ20140418095735629 and JSGG20140519104809878)
文摘This work investigates the evolution of structure and mechanical performance of metallic glasses（MGs）under a proposed rapid forming approach. Through the unique ultrasonic-assisted micro injection method, micro MGs parts with fine dimensional accuracy were successfully fabricated. The temperature during the micro injection is higher than the glass transition temperature and lower than the crystallization temperature. Differential scanning calorimeter curve and X-ray diffraction pattern show that the MGs micro parts keep the amorphous nature after the ultrasonic-assisted micro injection. Our results propose a novel route for the fast forming of MGs and have promising applications in the rapid fabrication of micro scale products and devices.
