Applied Petrochemical Research (v.4, #3)
Oxidative dehydrogenation of ethane to ethylene on Cr2O3/Al2O3–ZrO2 catalysts: the influence of oxidizing agent on ethylene selectivity by Y. Ramesh; P. Thirumala Bai; B. Hari Babu; N. Lingaiah; K. S. Rama Rao; P. S. Sai Prasad (247-252).
Oxidative dehydrogenation of ethane to ethylene was investigated on Al2O3, ZrO2 and Al2O3–ZrO2 mixed oxide supported Cr2O3 catalysts taking O2 and CO2 as oxidants. The catalysts were characterized by nitrogen adsorption, X-ray diffraction, temperature-programmed reduction, and X-ray photoelectron spectroscopy. The catalytic activity depended on the chromium species formed on the surface. However, the selectivity to ethylene was influenced by the oxidizing agent (O2 or CO2). Temperature-programmed desorption of ethylene was employed to confirm the role of oxidant in deciding ethylene selectivity.
Keywords: Oxidative dehydrogenation; Ethylene; CO2Chromia catalyst
Theories and experimental investigations of the structural and thermotropic mesomorphic phase behaviors of metal carboxylates by Peter N. Nelson; Richard A. Taylor (253-285).
Investigations on the phase behaviors and structural properties of mono-, di- and poly-valent metal carboxylates are reviewed with reference to developments in experimental and theoretical concepts surrounding their liquid crystalline properties. The main methods of structural investigation such as X-ray diffraction, infrared and 13C-NMR spectroscopies are examined in detail on the basis of common synthetic routes leading to the isolation of pure compounds. A detailed review of the thermal behaviors of several metal carboxylates is presented along with proposed theories and molecular models for odd–even alternation, chain length effects, phase structures and mesophase formation. Theories explaining the effects of metal ion radii and chain unsaturation are also discussed. Proposed degradation mechanisms resulting in the formation of various products and kinetic studies are also considered. Though this review highlights a number of investigations on the structural and phase properties of the mostly widely studied carboxylates, the results presented here strongly indicate that there is room for further studies on some of these systems.
Keywords: Metal carboxylates; Room temperature structures; Metal–carboxylate coordination; Odd–even alternation; Phase transition; Mesomorphism; Phase structures; Degradation mechanisms
A kinetic model for ethylene oligomerization using zirconium/aluminum- and nickel/zinc-based catalyst systems in a batch reactor by Adil A. Mohammed; Seif-Eddeen K. Fateen; Tamer S. Ahmed; Tarek M. Moustafa (287-295).
The aim of this work is to develop a kinetic model of the oligomerization of ethylene to linear alpha olefins (LAOs) for zirconium/aluminum and nickel/zinc catalyst systems. The development of such model helps in the study of the behavior of industrial LAOs reactors as well as in the optimization of their operation. The kinetic model was developed based on a four-step mechanism: site activation, initiation and propagation, chain transfer and site deactivation. A novel stochastic optimization algorithm, Intelligent Firefly Algorithm, was used to obtain the kinetic model parameters that best fit the available experimental data that were obtained from published sources. The values of the kinetic parameters were obtained for the developed kinetic models for two catalyst systems. The performance of the model with the estimated parameters was tested against the experimental data. The proposed kinetic model predicts the product distribution for the zirconium/aluminum catalyst system with suitable accuracy. The model can also predict the product distribution for the nickel/zinc catalyst system with good accuracy for all products. As expected, the accuracy of the model to predict the concentration of the higher carbon products decreases with the carbon number.
Keywords: Ethylene; Oligomerization; Modeling; Zirconium/aluminum catalyst; Nickel/zinc catalyst
Hydrogenolysis of bioglycerol to 1,2-propanediol over Ru/CeO2 catalysts: influence of CeO2 characteristics on catalytic performance by Gangadhara Raju; Damma Devaiah; Padigapati S. Reddy; Komateedi N. Rao; Benjaram M. Reddy (297-304).
Hydrogenolysis of glycerol to 1,2-propanediol is an alternative route for efficient utilization of biomass-derived glycerol to value-added chemicals. In this study, catalytic hydrogenolysis of glycerol was systematically investigated over various Ru/CeO2 catalysts. CeO2-support was prepared by different methods and Ru deposition by wet impregnation method. Synthesized catalysts were characterized by various techniques, namely, XRD, XPS, TPR, TPD, and other. Hydrothermally synthesized CeO2-supported Ru catalyst showed relatively more number of acid sites with mild acid strength and exhibited highest conversion and product selectivity. Effect of various parameters including Ru loading, reaction temperature, and hydrogen pressure was evaluated and addressed.
Keywords: Glycerol; Hydrogenolysis; Ru/CeO21,2-Propanediol; Hydrothermal; Support
Esterification of cooking oil for biodiesel production using composites Cs2.5H0.5PW12O40/ionic liquids catalysts by Jianxiang Wu; Yilong Gao; Wei Zhang; Yueyue Tan; Aomin Tang; Yong Men; Bohejin Tang (305-312).
Here, two ionic liquids 1-methyl-3-propane sulfonic-imidazolium (PSMIM) and 1-methyl-3-propane sulfonic-imidazolium hydrosulfate (PSMIMHSO4) are synthesized, and these ionic liquids mixed with different of heteropolyacid Cs2.5H0.5PW12O40 have been used as catalysts for esterification of cooking oil for preparation of biodiesel. Then those catalysts are characterized by Infrared spectrometer, X-ray diffractometer, nuclear magnetic resonance, elemental analyses and high-performance liquid chromatography. PSMIM and PSMIMHSO4 mixed with Cs2.5H0.5PW12O40 at the mass ratio of 1:1 are able to effectively catalyze esterification, using cooking oil as starting material at ratio of 1:20 (catalyst/cooking oil) and cooking oil to methanol at mass ratio of 1:6 for preparation of biodiesel with 3.5 h at 343 K. The result showed that 97.1 % yield of biodiesel could be obtained at optimized operation using PSMIMHSO4 mixed with Cs2.5H0.5PW12O40 at the mass ratio of 1:1 as catalyst.
Keywords: Cs2.5H0.5PW12O40Ionic liquid; Biodiesel; Acidic catalyst
Committee machine reaping of three well-known models: established between saturation pressure and gas chromatography data by Parisa Bagheripour; Mojtaba Asoodeh (313-316).
Saturation pressure is critical parameter of reservoir fluids which significantly affects petroleum engineering calculations. Accurate measurement of saturation pressure from laboratory experiment is very time, cost, and labor intensive. Therefore, it is favorable in most cases to achieve this parameter from empirical correlations. Three well-known models for estimation of saturation pressure from gas chromatography data include Elsharkawy model (EM), Soave–Redlich–Kwong (SRK), and Peng–Robinson (PR) equations of states (EOSs). This model proposes a novel approach, called committee machine, to reap beneficial advantages aforementioned three models through the combination of them. Committee machine produces a sophisticated model which performs in cooperation of EM, SRK and PR EOSs. Results indicated that CM model enhanced the accuracy of final prediction and performed more satisfyingly compared with individual model acting alone.
Keywords: Gas chromatography; Saturation pressure; Peng–Robinson equations of state; Redlich–Kwong equations of state; Committee machine
Study of feed temperature effects on performance of a domestic industrial PSA plant by Ehsan Javadi Shokroo; Mohammad Shahcheraghi; Mehdi Farniaei (317-323).
The Parsian N2-PSA industrial plant, situated in the southern pars zone of Iran, was studied numerically by mathematical modeling and numerical simulation. The model coupled PDEs are solved using fourth order Runge–Kutta scheme. In this work, we are dealing with the feed temperature and investigating its effect on the N2 purity and recovery, which is known as an operating variable. Finally, the results of simulations showed that the feed temperature near to 25 °C is well suited to N2 production with respect to its purity and recovery. In addition, as the feed temperature increases N2 productivity decreases.
Keywords: Pressure swing adsorption; Industrial plant; N2 production; Numerical simulation; Carbon molecular sieve