| 1 | Effect of Different Loadings on the Performance of Ni2P/Al2O3 Catalysts for Low-Temperature Thioethering and Selective Hydrogenation of Diolefins in Liquefied Petroleum Gas显示文摘In this study,different loadings of x%Ni_(2)P/γ-Al_(2)O_(3)(x=6%,9%,12%,15%,18%)catalysts with aluminum oxide(Al_(2)O_(3))as the carrier,nickel chloride(NiCl2)as the nickel(Ni)source,and ammonium hypophosphite(NH_(4)H_(2)PO_(2))as the phosphorus(P)source were prepared by the equal volume impregnation method to investigate the effects of different loadings on the performance of the selective hydrogenation of diolefins and thiol etherification in LPG.The physicochemical properties of the catalysts were characterized by XRD,BET,SEM,TEM,H_(2)-TPR,and XPS,and the catalytic activity of the catalysts was evaluated in a fixed-bed microreactor.The results showed that a change in the loading affected the catalyst crystalline phase structure and size,specific surface area,P coverage,active phase dispersion,and catalytic activity.At 6%,9%,and 12%loadings the catalysts had an Ni phase but there was no obvious Ni_(2)P phase in the nickel phosphide;at 15%loading a single Ni_(2)P phase was obtained,and at 18%loading both Ni_(2)P and Ni1_(2)P_(5) phases appeared.There was a P enrichment on the catalyst surface,and the higher the loading the more P species were enriched on the surface,but some of the P was lost during the catalyst reduction process due to the production of phosphine(PH3)gas.The 15%Ni_(2)P/γ-Al_(2)O_(3) catalyst had the largest Ni/Al ratio and the best dispersion.The Ni_(2)P active phase size was small at about 4.25 nm and Ni_(2)P was uniformly dispersed on the catalyst surface without agglomeration.The 15%Ni_(2)P/γ-Al_(2)O_(3) catalyst had the best catalytic activity at a pressure of 2.0 MPa,a liquid hourly space velocity(LHSV)of 3.0 h-1,and a hydrogen to hydrocarbon ratio of 12.The 1,3-butadiene conversion was 97.45%and the methanethiol removal was 100%at a temperature of 140℃. | Xiao Han Sun Jinru Song Guoliang Xie Xianna Ke Ming Tong Yanbing Zhao Zhiping Wang Zijian Li Jiahan | 2023 | China Petroleum Processing & Petrochemical Technology2023，25，1： | 0 |
| 2 | Three-dimensional elastic exact solution for free vibration of composite cylindrical shells considering ply angle显示文摘In order to obtain the exact free vibration solution of laminated cylindrical shell with arbitrary ply angle,the transfer matrix of transverse displacement and stress was established by combining the layer-wise theory with state space method.Based on the threedimensional elastic theory,the axial and circumferential displacement components were approximated using double helical pattern modes and the free vibration analytic formula of laminated cylindrical shell with arbitrary ply angle under simply supported boundary was derived.The exact form of the free vibration equation was obtained.The validity of the present theoretical method was performed by being compared with the theoretical model from the literature and finite element method.The results show that when the considered frequencies are less than two times the ring frequency,the calculation precision for natural frequency of thin shells is less than 1% and that of the thick shells is less than 2%.For the thick shells,the shell can be divided into multiple layers along the thickness direction,which can effectively improve the calculation precision.The influence of layer angle on the natural frequency was analyzed based on present method,the results shows that when the circumferential mode is low,the natural frequency is parabolic with the increasing of the layer angle and when the circumferential mode is high,the natural frequency increases monotonically with the increasing of the layer angle.The present method is also suitable for homogeneous isotropic shells and orthotropic cylindrical shells. | TONG Bo LI Yongqing ZHU Xi ZHANG Yanbing | 2019 | Chinese Journal of Acoustics2019，38，4： | 0 |
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