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Xia L.,Qingdao University of Science and Technology | Sun X.,Qingdao University of Science and Technology | Li Y.,China Petroleum Engineering and Construction Corporation CPECC | Xiang S.,Qingdao University of Science and Technology
Computer Aided Chemical Engineering

By combining Electrolyte NRTL and the NRTL activity coefficient model, and using the reaction kinetics of propylene chlorohydrins (PC) saponification and propylene oxide (PO) hydrolysis, the simulation of the saponification process in propylene oxide plant is accomplished. In order to reduce the Chemical Oxygen Demand (COD) of wastewater and improve the yield for propylene oxide, the effects of several conditions for the COD of wastewater are studied. The simulation results showed that the yield for propylene oxide has increased 0.47% and the COD of wastewater has reduced 371 mg/l in the case of the optimum condition. Moreover, the unit operation models and thermodynamic models used here had been proved accurately and reliably to simulate the saponification system. So the optimized operating conditions could provide the theoretical basis to the operation of propylene oxide plant. © 2012 Elsevier B.V. Source

Wei Q.,China University of Petroleum - Beijing | Li Y.,China Petroleum Engineering and Construction Corporation CPECC | Zhang T.,China University of Petroleum - Beijing | Tao X.,China University of Petroleum - Beijing | And 3 more authors.
Energy and Fuels

Composites of TiO2-SiO2 oxides (CTS) with various Ti/Si atomic ratios were prepared by the sol-gel method, and the CO2 supercritical fluid extraction method was used to remove solvent in the gel. The effects of the Ti/Si atomic ratio and calcination temperature on the specific surface area, pore structure, acidity, and coordination status of the Ti atoms were investigated by N2 desorption, pyridine adsorption, X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS), respectively. Hydrotreating catalysts were prepared with cobalt (Co)-molybdenum (Mo) and nickel (Ni)-tungsten (W) as active metal components supported on CTS-1 and CTS-4, respectively. The hydrotreating activities of the catalysts were tested by processing residue fluid catalytic cracking (RFCC) diesel on a fixed-bed reactor. It was found that hydrodesulfurization (HDS), hydrodenitrogenation (HDN), and hydrodearomatization (HDA) were affected by the acidity of the support and/or catalyst, which was related to the Ti/Si atomic ratio. The catalysts with strong Lewis acidity had better hydrotreating activities for HDS, HDN, and HDA. The study provides insight into a fundamental understanding of the relationship between the Ti/Si atomic ratio of the support and acidity of catalysts and the effect of acidity on the hydrotreating activity of the catalyst. © 2014 American Chemical Society. Source

Guo C.,China Petroleum Engineering and Construction Corporation CPECC | Han C.J.,China Petroleum Engineering and Construction Corporation CPECC | Tang Y.M.,Beijing University of Chemical Technology | Zuo Y.,Beijing University of Chemical Technology | Lin S.Z.,China Petroleum Engineering and Construction Corporation CPECC
Engineering Failure Analysis

The cracking of 0Cr13Al stainless steel tube bundle in condensate/heavy gas oil (HGO) heat exchanger in a petrochemical plant was studied to investigate the failure mechanism. The chemical composition, elements distribution and the morphology of the cracks were analyzed. The results showed that intergranular stress corrosion cracking (ISCC) was the main reason for this failure, and welding microfissures promoted the failure. Strict welding processes, and materials that are not susceptible to intergranular cracking, such as TP321 stainless steel, are suggested to avoid such failures in future application. © 2010 Elsevier Ltd. Source

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