Iranian Association of Chemical Engineering (IAChE) Iranian Journal of Chemical Engineering (IJChE) 1735-5397 13 1 2016 01 01 An optimization study by response surface methodology (RSM) on viscosity reduction of residue fuel oil exposed ultrasonic waves and solvent injection 3 19 15369 EN A. Mohammadi Doust Department of Chemical Engineering, Faculty of Engineering, Razi University, Kermanshah, Iran M. Rahimi Department of Chemical Engineering, Faculty of Engineering, Razi University, Kermanshah, Iran 0000-0002-1144-9351 M. Feyzi Department of Physical Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran Journal Article 2015 08 25 In this study, response surface methodology (RSM) based on central composite design (CCD) was applied for investigation of the effects of ultrasonic waves, temperature and solvent concentration on viscosity reduction of residue fuel oil (RFO). Ultrasonic irradiation was employed at low frequency of 24 kHz and power of 280 W. The results showed that the combination of ultrasonic waves and solvent injection caused to further reduce of viscosity. To obtain optimum conditions and significant parameters, the results were analyzed by CCD method. In this method, maximum viscosity reduction (133 cSt) was attained in ultrasonic irradiation for 5 min, temperature of 50 °C and acetonitrile volumetric concentration of 5 % by means of experimental and three dimensional response surface plots. The kinematic viscosity decreased from 494 cSt to 133 cSt at the optimum conditions. In addition, a multiple variables model was developed by RSM which the second-order effect of ultrasonic irradiation time was significant on viscosity reduction of FRO. Finally, a comparison between the RSM with artificial neural network (ANN) was applied. The results demonstrated that both models, , were powerful to predict of kinematic viscosity of RFO. The results demonstrated that both models, RSM and ANN, with R2 more than 0.99 were powerful to predict kinematic viscosity of RFO.

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Iranian Association of Chemical Engineering (IAChE) Iranian Journal of Chemical Engineering (IJChE) 1735-5397 13 1 2016 01 01 Optimization of Synthesis of Expandable Polystyrene by Multi-Stage Initiator Dosing 20 31 15377 EN F. Derakhshanfard Department of chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran 0000-0002-1552-4582 A. Vaziri Department of chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran N. Fazeli Department of chemical Engineering, Science and Research Branch, Islamic Azad University, P.O. Box 14155/4933, Tehran, Iran A. Heydarinasab Department of chemical Engineering, Science and Research Branch, Islamic Azad University, P.O. Box 14155/4933, Tehran, Iran Journal Article 2015 10 09 Suspension polymerization process is commonly used to produce expandable polystyrene. In the conventional method for producing this polymer, two different initiators are added to the process at two different temperature levels. In the industrial scale, this process is time consuming and difficult to control. A new method (Multi-Stage Initiator Dosing, MID) is proposed, in which, the initiator is dosed into the reactor. In the laboratory and bench scale tests of this new method results in better control of the process, shorter reaction times and better quality of the product. Optimum temperature and dosing intervals are determined. The properties of the prepared samples by MID and conventional methods are compared with each other. According to the results obtained with the implementation of new methods for the production of expandable polystyrene reduce time process and consuming amount of initiator and because the initiator dosing in several stages, the suspension control would be easier. Also absorption rate was higher pentane and grain size better than the conventional.

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Iranian Association of Chemical Engineering (IAChE) Iranian Journal of Chemical Engineering (IJChE) 1735-5397 13 1 2016 01 01 Lipase Immobilized into Novel GPTMS: TMOS Derived Sol-Gels and Its Application for Biodiesel Production from Waste Oil 32 46 15375 EN M. Nikpour Department of Energy, Materials and Energy Research Center, Meshkin Dasht, Karaj, Iran M. Pazouki Department of Energy, Materials and Energy Research Center, Meshkin Dasht, Karaj, Iran 0000-0002-3046-6392 Journal Article 2015 09 17 In this essay, lipase from Burkholderia cepacia was immobilized into 3-glycidoxypropyltrimethoxysilane (GPTMS) and tetramethoxysilane (TMOS) derived sol-gels. GPTMS:TMOS molar ratio of 1:3 was found to yield the best result. The morphological characteristics were investigated based on SEM and BET analysis. Sample mean pore diameter was 39.1 nm, it had a specific surface area of 60 m2/g prior to enzyme addition which decreased to 7.49 m2/g after immobilization. The enzyme activity was assessed through transesterification of waste cooking oil in the presence of ethanol with optimal conditions of: 40 ᵒC, 15 % immobilized lipase, 9:1 alcohol to oil molar ratio in 24 h of reaction which resulted to 91.70 % biodiesel production. In six-hour reaction time, 86.87 % biodiesel was obtained which is much shorter than conventional enzymatic transesterification which is 72 hours. Ethyl esters were characterized by determining their viscosity, density, and flash point based on ASTM D 6751-07b standards.

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Iranian Association of Chemical Engineering (IAChE) Iranian Journal of Chemical Engineering (IJChE) 1735-5397 13 1 2016 01 01 CO2 biofixation by Dunaliella Salina in batch and semi-continuous cultivations, using hydrophobic and hydrophilic poly ethylene (PE) hollow fiber membrane photobioreactors 47 59 15373 EN V. Mortezaeikia Process/production department, South Pars Gas Complex (SPGC), Asaluyeh, Iran R. Yegani Faculty of Chemical Engineering, Sahand University of Technology M.A. Hejazi Agricultural Biotechnology Research Institute of West & North-West, Tabriz, Iran S. Chegini Membrane Technology Research Center, Faculty of Chemical Engineering, Sahand University of Technology, Tabriz, Iran Journal Article 2015 09 09 In this work, performance of hollow fiber membrane photobioreactor (HFMPB) on the growth of Dunaliella Salina (G26) at various aeration rates (0.1 and 0.2 VVm) and medium re-circulation flow rates (500 and 1000 mL/h) were studied. Cultivation was carried out at both batch and semi-continuous modes in HFMPBs containing neat and hydrophilized in-house fabricated poly ethylene (PE) membranes at fixed light intensity of 300 µmol m-2 s-1and temperature of 30 oC. Microalgae showed better growth in hydrophobic module in both cultivation modes and modules. Maximum biomass concentration, CO2 biofixation and specific growth rates equal with 0.71g L-1, 1.102g L-1 d-1 and 0.224d-1 were obtained for non-wetted membranes, respectively. Comparing the performance of both modules showed that the impact of cultivation mode on the CO2 biofixation rate and CO2 removal is more pronounced than the impact of mass transfer resistance in membrane contactors. The obtained results show that the mean CO2 biofixation rates in semi-continuous cultivation for both neat and hydrophilized modules are higher than that in batch cultivation in all operating conditions. It was also found that the hydrophobic membranes are much preferable than hydrophilic membrane in HFMPBs.

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Iranian Association of Chemical Engineering (IAChE) Iranian Journal of Chemical Engineering (IJChE) 1735-5397 13 1 2016 01 01 Bubble formation on a single orifice in a gas solid fluidized bed using digital image analysis 60 72 15370 EN A. Dehghan Lotfabad School of Chemical Engineering, Iran University of Science and Technology (IUST), P.O. Box 16765-163, Tehran, Iran S. Movahedirad School of Chemical Engineering, Iran University of Science and Technology (IUST), P.O. Box 16765-163, Tehran, Iran M.T. Sadeghi School of Chemical Engineering, Iran University of Science and Technology (IUST), P.O. Box 16765-163, Tehran, Iran 0000-0002-3879-1923 Journal Article 2015 08 15 Digital Image Analysis (DIA) has been employed to characterize the time evolution of a bubble injected from a single orifice into a pseudo 2-dimansional gas-solid fluidized bed. The injected bubble diameter increased with the square root of time before detachment. During bubble free flight in the bed, its diameter remains approximately constant. The center of mass of the bubble increases with the second power of the time. The results show that the classical models for bubble injection can predict the time evolution of bubble diameter, and its center of mass. Bubble tends to elongate during injection and after detachment its height to width aspect ratio decreases. Image analyzing results used also for the study of gas leakage from the bubble to emulsion phase, and it has been shown that the dense phase expands up to 1.04 times of the minimum fluidization condition for large bubbles. The expansion ratio of the dense phase increases linearly with bubble diameter.

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Iranian Association of Chemical Engineering (IAChE) Iranian Journal of Chemical Engineering (IJChE) 1735-5397 13 1 2016 01 01 Prediction of the Effect of Polymer Membrane Composition in a Dry Air Humidification Process via Neural Network Modeling 73 83 15046 EN M. Fakhroleslam Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran A. Samimi Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran S.A. Mousavi Chemical and Petroleum Engineering Department, Sharif University of Technology, Azadi Ave., Tehran, Iran R. Rezaei Chemical Engineering Department, Razi University, Kermanshah, Iran Journal Article 2015 08 08 Utilization of membrane humidifiers is one of the methods commonly used to humidify reactant gases in polymer electrolyte membrane fuel cells (PEMFC). In this study, polymeric porous membranes with different compositions were prepared to be used in a membrane humidifier module and were employed in a humidification test. Three different neural network models were developed to investigate several parameters, such as casting solution composition, membrane thickness, operating pressure, and flow rate of input dry air which have an impact on relative humidity of the exhausted air after humidification process. The three mentioned models included Feed- Forward Back- Propagation (FBP), Radial Basis Function (RBF), and Feed- Forward Genetic Algorithm (FFGA). The developed models were verified by experimental data. The results showed that the feed- forward neural network models, especially FFGA, were suitable for prediction of the effect of membrane composition and operating conditions on the performance of this type of membrane humidifiers

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Iranian Association of Chemical Engineering (IAChE) Iranian Journal of Chemical Engineering (IJChE) 1735-5397 13 1 2016 01 01 An Empirical Correlation to Predict the Ignition Delay Time for Some Hydrocarbon Fuels 84 97 12114 EN F. S. Shariatmadar Faculty of Chemistry & Chemical Engineering, Malek-Ashtar University of Technology, Tehran, Iran Sh. Ghanbari Pakdehi Faculty of Chemistry & Chemical Engineering, Malek-Ashtar University of Technology, Tehran, Iran M. A. Zarei Faculty of Chemistry & Chemical Engineering, Malek-Ashtar University of Technology, Tehran, Iran Journal Article 2015 12 21 Examination of the available ignition delay time data and correlations in the case of methane, butane, heptane, decane, kerosene, Jet-A and ethylene fuels, allowed the derivation and recommendation of standard equations for this property. In this study, a new accurate substance dependent equation for ignition delay time as a function of pressure, number of carbon atoms, mixture equivalence ratio, fuel mole fraction and temperature has been developed to estimate ignition delay time of some hydrocarbon fuels. With the presented model, ignition delay time has been calculated and compared with the data reported in literature. The accuracy of the obtained model has been compared to the mostly used predictive models and the comparison indicated that the proposed correlation provides more accurate results than other models used in the previous works.<br style="font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" />

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