Modeling and Simulation
N. Hadi; A. Niaei; r. alizadeh
Volume 15, Issue 2 , May 2018, , Pages 22-37
Abstract
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 ...
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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.
Reaction Engineering, Kinetics and Catalysts,
S. M. S. Hosseini; H. Hashemipour rafsanjani; A.R. Talebizadeh
Volume 14, Issue 4 , December 2017, , Pages 3-16
Abstract
An alumina-supported nickel catalyst was prepared by impregnation of Ni2+ solution onto mesoporous alumina under microwave irradiation (denoted as M-Ni/Al2O3). For comparison, a catalyst with the same nickel content was prepared by conventional impregnation method (denoted as UM-Ni/Al2O3). Both M-Ni/Al2O3 ...
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An alumina-supported nickel catalyst was prepared by impregnation of Ni2+ solution onto mesoporous alumina under microwave irradiation (denoted as M-Ni/Al2O3). For comparison, a catalyst with the same nickel content was prepared by conventional impregnation method (denoted as UM-Ni/Al2O3). Both M-Ni/Al2O3 and UM-Ni/Al2O3 catalysts were applied to the syngas (H2 + CO) production by methane oxy-steam reforming in order to investigate the effect of preparation method on the catalytic performance. The reaction experiments were performed in a fixed-bed continuous flow reactor under atmospheric pressure. M-Ni/Al2O3 catalyst exhibited higher methane conversion (XCH4: 0.94) than UM-Ni/Al2O3 (XCH4: 0.58) in the oxy-steam reforming reaction. In addition, the value of syngas yield in M-Ni/Al2O3 (3.21 mole per mole of methane) was almost twice of one for UM-Ni/Al2O3 catalyst (1.59 mole per mole of methane). Various operating conditions such as the influences of the O2/CH4 and H2O/CH4 feed ratios, temperature, and GHSV on the methane conversion and yield of products were investigated. According to the structural characterization (FTIR, XRD, N2 adsorption/desorption, H2-TPR and TEM), the excellent catalytic performance of M-Ni/Al2O3 catalyst was reasonably attributed to the nano size and uniform distributed nickel species (<6 nm) which interacted to the alumina support strongly.
Reaction Engineering, Kinetics and Catalysts,
J. Pandey; A. Verma; R. Patel; Sh. Srivastava
Volume 14, Issue 4 , December 2017, , Pages 77-89
Abstract
The present paper deals with the kinetics and mechanism of homogeneously Ir(III) chloride catalyzed oxidation of D-mannitol by chloramine-T [CAT] in perchloric acid medium in the temperature range of 30 to 45 0C. The reaction is carried out in the presence of mercuric acetate as a scavenger for chloride ...
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The present paper deals with the kinetics and mechanism of homogeneously Ir(III) chloride catalyzed oxidation of D-mannitol by chloramine-T [CAT] in perchloric acid medium in the temperature range of 30 to 45 0C. The reaction is carried out in the presence of mercuric acetate as a scavenger for chloride ion. The experimental results show first order kinetics with respect to the oxidant [CAT] and catalyst [Ir(III)] while zero order with respect to substrate, i.e., D-Mannitol was observed. The reaction shows negligible effect of [Hg(OAc)2], [H+] and ionic strength of the medium. Chloride ion positively influence the rate of reaction. The reaction between chloramine-T and D-Mannitol in acid medium shows 2:1 stoichiometry. To calculate activation parameters, the reactions have been studied at four different temperatures between 30 to 45ºC. A mechanism involving the complex formation between catalyst and oxidant has been proposed. Mannonic acid has been identified chromatographically and spectroscopically as the final product of oxidation of D-Mannitol. Based on the kinetic data, reaction stoichiometry and product analysis, a reaction mechanism has been proposed and rate law has been derived.
Modeling and Simulation
Malihe Heravi; Mahdi Bayat; Mohammad Reza Rahimpour
Volume 13, Issue 4 , November 2016, , Pages 71-95
Abstract
The main focus of this study is improvement of the steam-methane reforming (SMR) process by in-situ CO2 removal to produce high hydrogen content synthesis gas. Sorption-enhanced (SE) concept is applied to improve process performance. In the proposed structure, the solid phase CO2 adsorbents and pre-reformed ...
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The main focus of this study is improvement of the steam-methane reforming (SMR) process by in-situ CO2 removal to produce high hydrogen content synthesis gas. Sorption-enhanced (SE) concept is applied to improve process performance. In the proposed structure, the solid phase CO2 adsorbents and pre-reformed gas stream are introduced to a gas-flowing solids-fixed bed reactor (GFSFBR). One dimensional mathematical model is developed to evaluate the effect of adsorbents on the efficiency of SMR at steady-state condition. To prove the accuracy of the considered model, simulation results are compared against available industrial plant data. Modeling results represent that application of SE method in SMR enhances syngas production and reduces CO2 content. The reported data indicate that by overcoming thermodynamic limitations and controlling coke formation, CH4 conversion and H2 yield improve about 23% and 29%, respectively. For more investigation, sensitivity analyses of some related parameters of the pre-reformed gas are performed to predict optimum conditions. Finally, the proposed GFSFBR for the SMR process leads to higher hydrogen production and H2/CO ratio. As the last part, non-dominated sorting genetic algorithm-II is applied to perform multi-objective optimization of the SE-SMR.