فهرست مطالب

Chemical Engineering - Volume:15 Issue: 2, Spring 2018

Iranian journal of chemical engineering
Volume:15 Issue: 2, Spring 2018

  • تاریخ انتشار: 1397/02/20
  • تعداد عناوین: 7
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  • N. Kakoui, M. Nikzad *, A. A. Ghoreyshi, M. Mohammadi Pages 3-21
    The present study investigates the potential applicability of the extracted pectin from sour orange pomace as adsorbent for Ni (II) removal from aqueous solution. Pectin extraction from the pomace was carried out using HCl and the highest pectin extraction yield of 26.75% was obtained. The Fourier transform infrared (FTIR) spectroscopy analysis confirmed that the structure of the extracted pectin was similar to the commercial one. The morphology and chemical characteristics of pectin beads were analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX) techniques. The influence of several parameters including pH, initial metal concentration, adsorption temperature and time was studied to optimize nickel removal. The maximum Ni (II) removal of 85.1% was obtained at initial concentration of 20 mg/L and the highest adsorption capacity of 19.76 mg/g was achieved at nickel concentration of 100 mg/L. Kinetic and equilibrium studies were done to evaluate Ni (II) sorption from aqueous solution by the synthesized beads. Results showed that the sorption process follows a pseudo- second- order kinetic model. The equilibrium data were well correlated with Langmuir and Redlich-Peterson models by high regression coefficients.
    Keywords: Pectin, Sour orange, Acidic extraction, adsorption, Nickel (II)
  • N. Hadi, A. Niaei, R. Alizadeh * Pages 22-37
    The high silica Mn-substituted MFI metallosilicate catalyst with Si/Al molar ratio of 220 and Si/Mn molar ratio of 50 was successfully synthesized by hydrothermal method. The catalyst sample was appropriately characterized by XRD, FE-SEM, EDX and BET techniques. The Mn-substituted MFI metallosilicate has not been reported as the potential catalyst for the methanol to propylene (MTP) reaction. The prepared catalyst was examined in the MTP reaction at the optimal operating conditions. Furthermore, for elucidating the flow field of the MTP fixed bed reactor, a three-dimensional (3D) reactor model was developed. A detailed reaction mechanism which was proposed for the MTP reaction over the Mn-impregnated MFI zeolite (Mn/H-ZSM-5) was properly employed. The reaction mechanism was integrated to a computational fluid dynamics (CFD) for simulating the kinetic, the energy equation and the hydrodynamics of the MTP process, simultaneously. The component distribution during proceeding of the MTP reaction was also simulated as a function of time on stream. The CFD modeling results were validated by the actual data which were obtained over the Mn-substituted MFI metallosilicate catalyst. With regard to the findings, the experimental data were in good agreement with the predicted values of the CFD modeling.
    Keywords: Mn-substituted MFI metallosilicate, Methanol to propylene, CFD modeling, detailed reaction mechanism, energy equation
  • M. Ghashghaee *, S. Shirvani, V. Farzaneh Pages 38-51
    Furfural is one of the most promising chemical platforms with bright perspective with respect to the production of biobased chemicals and fuels from lignocellulosic material. Globally, the majority of this biomass derived chemical is converted into furfuryl alcohol, a building block in polymers industry. The vapor-phase hydrogenation of furfural over copper species dispersed on two types of silica (bulk-type and nano-sized) supports with or without chromium as a promoter was studied for the first time. The catalysts were synthesized via impregnation method and operated under mild hydrogenation reaction conditions. The results represented that the catalytic performance of the nano-sized silica-supported catalyst was better in terms of furfural conversion, furfuryl alcohol yield and selectivity than that of the bulk-type silica after 4 hours of operation. However, by incorporation of chromium as a promoter, the bulk-type silica-supported catalyst exhibited an improved performance during the whole run length (higher than 82% and 96% of furfural conversion and furfuryl alcohol selectivity, respectively).
    Keywords: Hydrogenation, Furfuryl alcohol, Nano silica, Promoter, Impregnation, Chromium, Biomass, Biomonomers
  • I. Khosrozadeh, M.R. Talaghat *, A.A. Roosta Pages 52-64
    Catalytic naphtha reforming is one of the most important processes in which, low quality naphtha is converted into high octane motor gasoline. In this study, a mathematical model was developed and was used for investigation the effect of temperature, pressure, hydrogen to hydrocarbon ratio on the octane number, the yield of product and the undesirable phenomena of coke deposition in a semiregenerative catalytic reforming unit. The result of the model was compared to the plant data to verify the model accuracy. Then, the model was used to find the optimal condition for the maximum value of octane number and yield of product and the minimum value of coke deposition. The optimum condition of the process is estimated using genetic algorithm optimization method as an efficient optimization method. In the optimal condition, the octane number and the yield of the product are improved 0.3% and 1.23% respectively, and the coke deposition is reduced 2.1 %.
    Keywords: Catalytic naphtha reforming, Octane number enhancement, Hydrogen production, Optimization
  • A. Barzegari, Z. Shariatinia * Pages 65-77
    Novel electrospun nanofibrous CS-PEO nerve conduits containing 0, 2.5 and 5% of green tea methanolic extract were developed and characterized by FE-SEM, FT-IR, TGA/DSC as well as tensile strength analysis. The FE-SEM images revealed that all of the nanofibers had an average diameter of ∼80nm. The swelling degree was decreased by increasing the GT amount from 2.5 to 5% and this might be attributed to the enhanced interactions of the NH2, C(O)NH2 and OH groups of chitosan and PEO polymers with the OH groups of GT leading to a less hydrophilic mat surface, thus reducing the attraction by the aqueous medium. Moreover, the swelling was the highest in acidic medium but it was decreased in the neutral environment and it had the least value within the alkaline medium. The CS-PEO-5%GT exhibited the highest antibacterial activity among three samples examined against both S. aureus and E. coli microorganisms. The CS-PEO-5%GT was proved to be a very suitable candidate to be used as nerve conduit due to its improved tensile and antibacterial activities.
    Keywords: Nerve Conduit, Electrospinning, Green Tea Extract, Chitosan, Polyethylene Oxide
  • K. Movagharnejad *, F. Saffar Pages 78-90
    In the present research, three different architectures were investigated to predict the coefficients of the Daubert and Danner equation for calculation of saturated liquid density. The first architecture with 4 network input parameters including critical temperature, critical pressure, critical volume and molecular weight, the second architecture with 6 network input parameters including the ones in the first architecture with acentric factor and compressibility factor. The third architecture contains 12 network input parameters including 6 input parameters of the second architecture and 6 structural functional groups of different hydrocarbons. The three different architectures were trained and tested with the 160 sets of Daubert and Danner coefficients gathered from the literature. The trained neural networks were also applied to 15 un-known hydrocarbons and the outputs (Daubert and Danner coefficients) were used to predict the saturated liquid densities. The calculated liquid densities were compared with the experimental values. The Results indicated that the coefficients obtained from the second architecture produced more precise values for the liquid densities of the 15 selected hydrocarbons.
    Keywords: Density, modeling, Neural Networks, Structural decomposition, Daubert, Danner equation
  • P. Rashidi Zonouz, M.E. Masoumi, A. Niaei *, A. Tarjomannejad Pages 91-102
    In this paper, catalytic oxidation of CO over the LaFe1-xCuxO3 (x= 0, 0.2, 0.4, 0.6) perovskite-type oxides was investigated. The catalysts were synthesized by sol-gel method and characterized by XRD, BET, FT-IR, H2-TPR and SEM methods. The catalytic activity of catalysts was tested in catalytic oxidation of CO. XRD patterns confirmed the synthesized perovskites to be single-phase perovskite-type oxides. The synthesized perovskite catalysts show high activity in the range of reaction temperature (50 - 300 ºC). The substitution of Cu in B-site of the perovskite catalysts enhanced their catalytic activity for CO oxidation. Among different synthesized perovskite catalysts, LaFe0.6Cu0.4O3 has the highest activity: nearly complete elimination of CO was achieved at 275 ºC with this catalyst. Kinetic studies for CO oxidation were performed based on power law and Mars-van Krevelen mechanisms. According to kinetic calculations, the most probable mechanism is the MKV-D (dissociative adsorption of oxygen) which can predict the experimental data with correlation coefficient of R2 > 0.995.
    Keywords: CO Oxidation, Perovskite, LaFe1-xCuxO3, Kinetic, MVK mechanism