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Maede Salmasi,Shohreh Fatemi,Ali Taheri Najafabadi 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.4
SAPO-34 catalysts were synthesized by the hydrothermal method using morpholine and/or TEAOH templates. The sample prepared by the combination of TEAOH and morpholine exhibited more crystallinity and smaller particle size. Furthermore, SAPO-34 was modified with Ni and Mg to improve its performance for conversion of methanol to olefin. These catalysts were characterized by XRD, SEM, EDX,BET, FTIR and NH3-TPD techniques. The catalytic performance of catalysts was studied in MTO reaction at 673 K and atmospheric pressure by a feed WHSV of 8.7 h1 in a fixed bed reactor. The modified catalysts showed higher selectivity to light olefins and longer lifetime. NiAPSO-34 catalyst showed the best performance; the yield of ethylene and propylene was determined to be 94 wt.% with 100% methanol conversion.
Khadijeh Sherafatmand,Shohreh Fatemi,Zeinab Salehi 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.30 No.-
Catalytic activity of the whole cell baker’s yeast (Saccharomyces cerevisiae) was studied for convertingacetaldehyde (AC) to ethanol (ET) in a gas-phase packed bed reactor. The baker’s yeast was considered atfree and immobilized conditions, to convert AC as an air pollutant to the less harmful product of ET. Theinfluence of operating conditions, such as inlet AC concentration, cells’ water content and temperature,was studied on the cells’ activity. The best conditions from the point of ET productivity and cell stabilitywas detected at temperature of 318 K and water content of 0.23 0.02 g water/g dry cell, using free cells. The cell immobilization was performed by doping on the surface of multiwalled carbon nanotube (CNT)under a mild centrifugal force. The activity of CNT-immobilized cells towards ET formation was improved by6% and the stability of the cells was improved by 43% respectively in comparison with the free cells’ activityand stability.
Maede Salmasi,Shohreh Fatemi,Yadollah Mortazavi 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.39 No.-
TiO2 nanoparticles (TNP) were converted to TiO2 nanotubes (TNT) and investigated as the catalyst foroxidative desulfurization of dibenzothiophene. The TNT was promoted with Cu (Cu-TNT) to increase theODS efficiency. The textural and structural properties of catalysts were characterized and confirmed byXRD, FESEM, EDS, TEM, FTIR and BET analysis. The maximum conversion over TNT was achieved at thetemperature = 326.6 K, oxidant/DBT = 13.9 mol/mol and catalyst/fuel = 10 g/l. At the optimum condition,TNT has shown 10% higher efficiency compared with TNP catalyst. The promoted TNT with less that1 wt% Cu accelerated the ODS rate of reaction with 10% excess conversion, to achieve 98% conversion ofDBT.
Milad Komasi,Shohreh Fatemi,Marjan Razavian 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.7
SAPO-34 molecular sieve with tuned hierarchical structure was synthesized and used as the catalytic support for propane dehydrogenation (PDH) reaction to receive propylene with high selectivity. Synthesized material was characterized by XRD, FESEM, BET, ICP, FT-IR and TPO techniques. The Pt-Sn/SAPO-34 (hierarchical and regular ones) catalysts were prepared by impregnation method, and then the catalytic activity and selectivity of the catalysts were evaluated in PDH reaction. The results were compared with commercial Pt-Sn/γ-Al2O3 catalyst at the same operational conditions. Results revealed that hierarchical SAPO-34 based catalyst was the most efficient catalyst with superior activity and high propylene selectivity. The results suggested higher stability of the catalyst with hierarchical structure during seven hours reaction. Moreover, the impact of operational conditions was investigated on the performance of Pt-Sn/hierarchical SAPO for the temperature range of 550-650 oC, weight hourly space velocity of 4 and 8 h−1 and H2/ C3 molar ratios of 0.2-0.8, at normal pressure.
Mojtaba Masoudi-Nejad,Shohreh Fatemi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.6
Adsorption of CH4, C2H6 and C2H4, the feed and main products of oxidative coupling process of methane(OCM) has been studied on silicoalumina-phosphate molecular sieve (SAPO-34) in mild conditions. Theexperiments were conducted in a batch system based on volumetric adsorption measurement techniquefor determination equilibrium adsorption capacity in the absolute pressure range of 100–1000 kPa andat the isothermal temperatures of 303, 313 and 323 K. Various isotherm equations were fitted on theadsorption equilibrium data and the model parameters were predicted as a function of temperature. Isosteric heats of adsorption were determined using Clausius–Clapeyron equation at different surfacecoverage. Maximum capacity of SAPO-34 was observed at 303 K and 880–900 kPa equilibrium pressurewith 1.25, 2.02 and 4.67 mmol/g adsorbed amount for methane, ethane and ethylene adsorption,respectively. The adsorption selectivity of ethane and ethylene against methane were determined andthe appropriate potential of SAPO-34 was observed for separation of OCM products from methane. Theisotherm models and enthalpy of adsorption can be efficiently used for the simulation of the adsorptionprocess constructed at the downstream of the OCM process for separation of ethane and ethylene frommethane.
Nader Javanmardi Nabikandi,Shohreh Fatemi 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.30 No.-
Kinetic modelling of a sulfur recovery unit based on straight through sour natural gas was performed bynumerical programming and the model outlet results were compared with industrial data. A recovery of97.4 mole% sulfur was observed from this unit. It was revealed that kinetic model precisely predicted the outlet results of sulfur, H2S, SO2 and CO2with 4% absolute relative deviation in combustion furnace and 2% in catalytic convertors. Theequilibrium model has shown 3% deviation for prediction of H2S/SO2 ratio from the furnace, whereas thekinetic model has shown only 0.2% deviations from the real results.
Kinetic modeling and optimization of the operating condition of MTO process on SAPO-34 catalyst
Ali Taheri Najafabadi,Morteza Sohrabi,Maede Salmasi,Shohreh Fatemi 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.1
In this paper, a new kinetic model for methanol to olefin process (MTO) over SAPO-34 catalyst was developed based on data obtained from a micro catalytic reactor using appropriate reaction network. The reaction rate equation has been introduced with consideration of reaction mechanism and the parameters were optimized on the experimental data by genetic algorithm. Comparing the experimental and predicted data showed that the predicted values from the presented model are well fitted to the experimental data. Using this kinetic model, the effect of most important operating conditions such as temperature, pressure, inlet water to methanol molar ratio and methanol space–time on the product distribution, has been examined. Finally, the optimal operating conditions for maximum production of the ethylene and the propylene were introduced.