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Keshavarz A.R.,Catalyst and Advanced Materials Research Laboratory | Rezaei M.,Catalyst and Advanced Materials Research Laboratory | Yaripour F.,Petrochemical Research and Technology Company NPC RT
Powder Technology | Year: 2010

In this article, mesoporous nanocrystalline γ-Al2O3 with high surface area is synthesized by a simple sol-gel method with cationic surfactant as template. This sample is used for vapor-phase dehydration of methanol to Dimethyl ether. The synthesized catalyst showed a high surface area of 375 m2 g- 1 and a crystallite size of about 3.9 nm. NH3-TPD analysis revealed that the sample with smaller crystallite size possesses higher concentration of medium acidic sites and consequently the catalytic activity. © 2010 Elsevier B.V. All rights reserved. Source


Golhosseini Bidgoli R.,Amirkabir University of Technology | Naderifar A.,Amirkabir University of Technology | Mohammadrezaei A.R.,Petrochemical Research and Technology Company NPC RT | Jafari Nasr M.R.,Petrochemical Research and Technology Company NPC RT
Iranian Journal of Chemistry and Chemical Engineering | Year: 2012

Thermodynamic restrictions and simultaneous effects of operational conditions on the homogeneous rhodium-catalyzed carbonylation of methanol are studied in this line of research. It is shown that the general NRTL-Virial model can be appropriated to study thermodynamics of the carbonylation. It is obtained that the reaction is kinetically and thermodynamically reasonable at temperatures above 420K and below 520K, respectively. Moreover, at carbon monoxide partial pressures above 10 bar, the reaction rate is independent of the partial pressure. These results are in full accord with those reported in the literature. In addition, PCO > 2 bar is necessary for initializing the reaction. The parameters involved in the rate expression, equilibrium constants, CO solubility, and rate constant, are determined. The equilibrium constants are calculated with B3LYP/SDD ab initio method, and the value of Henry's coefficient for CO (H CO) is determined as a function of temperature and methyl acetate conversion. The results predicted by this function agree well with those proposed by the general NRTL-Virial model with the errors below 11%. The Variation of CO solubility with acetic acid and methyl acetate concentrations is in good agreement with that obtained by others. It is found that the determined parameters give satisfactory predictions in modeling and simulation of the reaction. Source


Meshkani F.,University of Kashan | Rezaei M.,University of Kashan | Jafarbegloo M.,Petrochemical Research and Technology Company NPC RT
Materials Research Bulletin | Year: 2015

Nanocrystalline Fe2O3-Cr2O3-CuO powder was prepared by a modified urea hydrolysis method and employed as catalyst for high temperature water gas shift reaction. The prepared powders were characterized by XRD, BET, TPR, FTIR, and TEM techniques. The effect of preparation factors (aging time and temperature) was investigated on the physical and catalytic properties of the prepared samples. The results showed that aging temperature and time have a significant effect on the physical and catalytic properties of catalysts. The catalytic results revealed that the Fe2O3-Cr2O3-CuO catalyst prepared with urea hydrolysis method possessed higher surface area and catalytic activity compared to commercial catalyst. In addition, TEM analysis showed that the prepared catalyst possessed a nanocrystalline structure with crystallite size less than 15 nm. The results indicated that increase in calcination temperature decreased the BET area and consequently decreased the catalytic activity. The prepared catalyst exhibited stable catalytic performance in high temperature water gas shift reaction. © 2014 Elsevier Ltd. All rights reserved. Source


Meshkani F.,University of Kashan | Rezaei M.,University of Kashan | Jafarbegloo M.,Petrochemical Research and Technology Company NPC RT
Materials Research Bulletin | Year: 2015

Nanocrystalline Cr-free Fe-Al-Cu catalysts with high surface area and mesoporous structure was prepared by coprecipitation method and employed in high temperature water gas shift reaction. Several parameters such as pH, aging temperature and aging time were optimized by the Taguchi method of experimental design. The sample prepared under optimized conditions showed a high surface area of 208 m2 g-1, pore size of 3.76 nm and theoretical particle size of 5.47 nm after calcination at 400 °C for 4 h. This catalyst illustrated the highest CO conversion compared to other prepared catalysts. These results confirmed that the Taguchi method is an effective method of determining the optimum parameters in preparation process of high temperature water gas shift catalyst. Moreover, the effect of calcination temperature, GHSV and steam/gas ratio on the catalytic performance of optimized Fe-Al-Cu catalyst was investigated. © 2015 Elsevier Ltd. All rights reserved. Source

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