Reaction Engineering, Kinetics and Catalysts,
Volume 7, Issue 2 , April 2010, , Pages 58-67
Process Control and Engineering, Process Safety, HSE
Volume 11, Issue 3 , July 2014, , Pages 59-66
Modeling and Simulation
J. Saien; M. Kharazi; S. Asadabadi
Volume 12, Issue 2 , April 2015, , Pages 59-74
Abstract
e"> The adsorption behavior of three amphiphilic ionic liquids (ILs), 1-alkyl-3- methylimidazolium chloride {[Cnmim][Cl], n=68}at the interface of n-butyl acetate + water system was studied with IL concentration range of 1.00×104-1.00×101 mol·dm3 and temperature range of 293.2-318.2 ...
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e"> The adsorption behavior of three amphiphilic ionic liquids (ILs), 1-alkyl-3- methylimidazolium chloride {[Cnmim][Cl], n=68}at the interface of n-butyl acetate + water system was studied with IL concentration range of 1.00×104-1.00×101 mol·dm3 and temperature range of 293.2-318.2 K. The ILs behave as strong surfactants in this chemical system and significantly reduce the interfacial tension with the order of their alkyl chain length and is consistent with their hydrophobicity nature. An almost linear decrease of interfacial tension with temperature was also relevant. The experimental data were satisfactorily reproduced with Szyszkowski equation, implying an ideal ILs adsorption. In this regard, the Langmuir maximum interface excess and equilibrium adsorption constant were obtained at different temperatures for each IL. Accordingly, effectiveness of adsorption and adsorption tendency increase with the alkyl chain length. At the saturated interface, increasing temperature leads to declining Langmuir maximum interface excess due to disrupting surrounding water molecules around ILs hydrophobic portions. However, adsorption tendency of ILs increases slightly with temperature.
Process Control and Engineering, Process Safety, HSE
Volume 10, Issue 3 , July 2013, , Pages 60-75
Modeling and Simulation
R. Rahimi; M. H. Soodmand; M. Zivdar; A. Alborzi; M. Rahmanian
Volume 12, Issue 1 , January 2015, , Pages 60-67
Abstract
The distillation process remains as the most common method ofseparation in chemical process industries. The energy used from this process accounts for an estimated 3% of the world energy consumption. The Dividing-Wall Column (DWC) for separation of multi-component mixtures has recently become a major ...
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The distillation process remains as the most common method ofseparation in chemical process industries. The energy used from this process accounts for an estimated 3% of the world energy consumption. The Dividing-Wall Column (DWC) for separation of multi-component mixtures has recently become a major concern ofindustries. The design ofDWC is based on Thermally Coupled Distillation System (TCDS) eliminating some of the operational equipment. This paper presents the results of simulation of a DWC by using 3-simple sequence column model based on shortcut method by a commercial chemical Engineering software for purification of1,3 butadiene unit. From the results, it is shown, by using a DWC instead of two conventional sequential column, the heat duties ofboth the condenser and the reboiler are reduced about 28.5% and also desirable purity ofthe key-components for the case ofstudy have been achieved.
Process Control and Engineering, Process Safety, HSE
Volume 3, Issue 4 , October 2006, , Pages 60-75
Abstract
The spreading of a tracer in a bubbly two-phase grid-generated turbulent flow system is studied. In this work both particle image velocimetry (PIV) and planer laser-induced fluorescence (PLIF) are used to study the effect of the dispersed phase flow rate on the mixing characteristics of the tracer. The ...
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The spreading of a tracer in a bubbly two-phase grid-generated turbulent flow system is studied. In this work both particle image velocimetry (PIV) and planer laser-induced fluorescence (PLIF) are used to study the effect of the dispersed phase flow rate on the mixing characteristics of the tracer. The turbulent intensity of the continuous phase in the bubbly two-phase grid-generated turbulent flow is close to isotropic, and increasing the gas void fraction reduces the degree of non-isotropicity. The self-similarity of mean and RMS values of the cross-stream concentration distribution is observed. A new mathematical model is suggested to describe the self-similarity of the cross-stream profiles of the mean concentration based on two separate Gaussian curves into the central and outer region of the flow. The turbulent diffusivity is calculated using the Taylor hypothesis, which is based on the growth of the variance of the cross-stream profiles of the mean concentration, with a position along the direction of the flow. An increase in the void fraction does not affect the diffusivity of the superimposed distribution of the plume in the central region, however it did increase in the outer region.
Environmental Engineering,
Volume 2, Issue 1 , January 2005, , Pages 61-70
Abstract
This article presents the research results on production and performance of palladium-only catalytic converters. Monolith is used as the catalyst carrier and gamma alumina as the substrate. Dipping method is used for monolith washcoating. Palladium as the active metal is impregnated on gamma alumina ...
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This article presents the research results on production and performance of palladium-only catalytic converters. Monolith is used as the catalyst carrier and gamma alumina as the substrate. Dipping method is used for monolith washcoating. Palladium as the active metal is impregnated on gamma alumina using wet impregnation to produce catalyst samples. The effects of factors such as percent solids in slurry, milling time, calcination time and temperature, pH and existence of Al(NO3)3 on wash-coat characteristics were studied experimentally. SEM, XRD and BET tests were carried out on the samples. Catalyst performance was tested in an experimental reactor that was designed for this research. The results show that catalytic activity increases as calcination time increases, whereas it declines as calcination temperature increases. Furthermore, as the slurry pH decreases, the catalytic activity also decreases. It was observed that impregnation of Al(NO3)3 does not have any effect on catalytic activity.
Modeling and Simulation
Volume 6, Issue 4 , October 2009, , Pages 62-72
Abstract
In this study some properties ofthe methanol-water mixture such as diffusivity, density, viscosity, and hydrogen bonding were calculated at different temperatures and atmospheric pressure using molecular dynamics simulations (MDS). The results were compared with the available experimental data as well ...
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In this study some properties ofthe methanol-water mixture such as diffusivity, density, viscosity, and hydrogen bonding were calculated at different temperatures and atmospheric pressure using molecular dynamics simulations (MDS). The results were compared with the available experimental data as well as some theoretical models; overall indicating a good agreement. This shows the useful and effective application of MDS for determination ofphysical properties.
Environmental Engineering,
Volume 5, Issue 3 , July 2008, , Pages 62-67
Abstract
Airborne particulate matter (PM10 ) was collected from the atmosphere of the city of Isfahan. The concentration of heavy metals and anions associated with airborne particulate matter were determined using atomic absorption spectrometric and ion chromatographic techniques. A comparison was made between ...
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Airborne particulate matter (PM10 ) was collected from the atmosphere of the city of Isfahan. The concentration of heavy metals and anions associated with airborne particulate matter were determined using atomic absorption spectrometric and ion chromatographic techniques. A comparison was made between the variation in the concentration of PM10 and that for heavy metals and CO. An excellent similarity was found between the variation model of PM10, heavy metals and CO. Due to the atmospheric concentrations of heavy metals, the enrichment factors were calculated and showed that the well-known toxic heavy metals are mostly released into the city atmosphere from anthropogenic sources.
Transport Phenomena,
Volume 11, Issue 1 , January 2014, , Pages 63-68
Modeling and Simulation
Volume 6, Issue 2 , April 2009, , Pages 63-74
Modeling and Simulation
M Omidifar; S Shafiei; H Soltani
Volume 13, Issue 3 , July 2016, , Pages 63-77
Abstract
In modern refineries, hydrogen is widely used for the production of clean fuels. In this paper, a new method is presented in order to use hydrogen more effectively in refineries. This new method is based on combination of linear programming with imperialist competitive algorithm (ICA) in order to optimize ...
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In modern refineries, hydrogen is widely used for the production of clean fuels. In this paper, a new method is presented in order to use hydrogen more effectively in refineries. This new method is based on combination of linear programming with imperialist competitive algorithm (ICA) in order to optimize the hydrogen distribution network. In this new approach, optimization is performed in two levels. In one level the hydrogen network layout is proposed by ICA and in the other level the total annual cost and utility are optimized by the linear programming. Thus, the minimum cost and the optimal configuration of the hydrogen distribution network are obtained. Finally, to illustrate the application of this method two cases are studied.
Reaction Engineering, Kinetics and Catalysts,
Volume 5, Issue 2 , April 2008, , Pages 64-70
Abstract
"> The influence of SiO2 and Al2O3 binders on the catalyst performance and products selectivity of the precipitated Fe-Cu-K catalyst physically mixtured with HZSM-5 was studied in a fixed bed tubular reactor. The iron catalyst was mixed with HZSM-5 zeolite and shaped to cylinders form by alumina and ...
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"> The influence of SiO2 and Al2O3 binders on the catalyst performance and products selectivity of the precipitated Fe-Cu-K catalyst physically mixtured with HZSM-5 was studied in a fixed bed tubular reactor. The iron catalyst was mixed with HZSM-5 zeolite and shaped to cylinders form by alumina and or silica as a binder for increasing the mechanical strength of bifunctional catalyst. The catalyst activity was tested under reaction condition, P=17 bar, T=290 oC , H2/CO=1 and GHSV= 3.07 NL.h-1.g.Fe-1. The results showed that the catalyst activity for Fischer – Tropsch and water gas shift reactions for silica binders is lower than alumina and secondary reactions in the presence of alumina is higher.
Thermodynamics,
Volume 3, Issue 2 , April 2006, , Pages 64-72
Modeling and Simulation
Volume 10, Issue 4 , October 2013, , Pages 65-78
Separation Technology,
Volume 5, Issue 1 , January 2008, , Pages 65-73
Abstract
e"> In order to study the effective factors on the quality and quantity of lecithin extracted from soybean oil and the residual amount of phosphatids in degummed oil, this study was arranged. Crude oil recovered from soybean which had been processed by conventional solvent extraction and reached a ...
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e"> In order to study the effective factors on the quality and quantity of lecithin extracted from soybean oil and the residual amount of phosphatids in degummed oil, this study was arranged. Crude oil recovered from soybean which had been processed by conventional solvent extraction and reached a phosphorus content of 454 ppm was used for this purpose. Treatments were carried out under different concentrations of phosphoric acid (zero, 0.05, 0.1, 0.2, 0.5, 2) and different percents of water ( 0.5, 1, 2, 5, 3, 4) at different temperatures (25, 50, 60, 75, 90 °C) and with different stirring times (5,10, 20, 40, 60 min). The highest phosphatid recovery was obtained with 3 %(v/v) water at 75 °C with a stirring time of 20 minutes. Adding phosphoric acid decreased the phosphatid residue in the degummed oil, but the quality of lecithin was reduced. However, the addition of phosphoric acid lower than 0.05 %(v /v) at 60 °C resulted in the same recovery efficiency with no major effect on the quality of lecithin.
Process Control and Engineering, Process Safety, HSE
Volume 3, Issue 1 , January 2006, , Pages 65-76
Process Control and Engineering, Process Safety, HSE
Volume 3, Issue 3 , July 2006, , Pages 65-74
Abstract
The aim of this study was to investigate the particulate dispersion from Kerman Cement Plant. The upwind – downwind method was used to measure particle concentration and a cascade impactor was applied to determine particle size distribution. An Eulerian model, Gaussian plume model and an artificial ...
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The aim of this study was to investigate the particulate dispersion from Kerman Cement Plant. The upwind – downwind method was used to measure particle concentration and a cascade impactor was applied to determine particle size distribution. An Eulerian model, Gaussian plume model and an artificial neural network have been used to compute and predict concentration of PM10 from Kerman Cement Plant. Eulerian model incorporates source related factors, meteorological factors, surface roughness and particle settling to estimate pollutant concentration from continuous sources. The measured data have been used to create an artificial neural network for predicting suspended particle concentration from Kerman Cement Plant. The data includes particle concentration, distance from source, mixing height, lateral and vertical dispersion parameters and 10 meters wind speed. The performance of these models has been compared with the measured data. The AAPD (Average Absolute Percent Deviation) parameter for the results of the Eulerian model, Gaussian model and ANNs was 25.53%, 15.38% and 5.91% respectively.
Separation Technology,
M. Azimi; S.J. Peighambardoust
Volume 14, Issue 3 , August 2017, , Pages 65-81
Abstract
In this work, we prepared the nafion/montmorillonite/heteropolyacid nanocomposite membranes for direct methanol fuel cells (DMFCs). The analyses such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM) were conducted to characterize the filler dispersion ...
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In this work, we prepared the nafion/montmorillonite/heteropolyacid nanocomposite membranes for direct methanol fuel cells (DMFCs). The analyses such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM) were conducted to characterize the filler dispersion and membrane structure in prepared nanocomposite membranes. XRD patterns of nafion-CsPW-MMT nanocomposites membranes showed the exfoliated structure of membranes by adding MMT and CsPW. SEM-EDXA results showed proper dispersion of nanoparticles in the membrane matrices. Addition of CsPW-MMT to nafion membranes increases water uptake and IEC due to increase hydrophilic groups in membranes. The proton conductivity results showed that proton conductivity increases by increasing amount of CsPW and decreasing of clay content in the membrane. Methanol crossover through polymer electrolyte membranes is a critical issue and causes an important reduction of performance in DMFCs. The developed intercalated nafion/CsPW/MMT nanocomposite membranes have successfully improved the membrane barrier properties due to the unique feature of MMT which contributed to the formation of a longer pathway towards methanol across the membrane. The lowest methanol crossover of the developed membranes in this study was 1.651×10-6 cm2 s-1 which was lower than re-cast nafion membrane (2.078×10-6 cm2 s-1). The methanol permeability was significantly reduced by the incorporation of MMT and increased by addition of CsPW in the nafion membrane. Finally, according to the selectivity results, the nafion-MMT-CsPW nanocomposite membrane with MMT mass fraction of 2.5% and CsPW mass fraction of 8% shows the best membrane selectivity and this nanocomposite membrane could be suitable for application in DMFCs.
Petroleum and Reservoir Engineering
Volume 6, Issue 1 , January 2009, , Pages 66-73
Modeling and Simulation
Volume 10, Issue 2 , April 2013, , Pages 67-80
Modeling and Simulation
Volume 10, Issue 1 , January 2013, , Pages 67-78
Reaction Engineering, Kinetics and Catalysts,
B. Izadkhah; D. Salari; A. Niaei; A. Tarjomannejad
Volume 14, Issue 1 , March 2017, , Pages 67-73
Abstract
In this paper, LaBO3 perovskite type catalyst formulations were prepared by sol-gel auto combustion method using citric acid as the fuel. Activity of catalysts was tested in catalytic oxidation of toluene as a model of volatile organic compounds. LaCoO3 perovskite formulation showed the highest activity ...
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In this paper, LaBO3 perovskite type catalyst formulations were prepared by sol-gel auto combustion method using citric acid as the fuel. Activity of catalysts was tested in catalytic oxidation of toluene as a model of volatile organic compounds. LaCoO3 perovskite formulation showed the highest activity among LaBO3 (Fe, Mn and Co) perovskite catalysts. So, LaCoO3 perovskite based catalyst was selected for further investigation and modification in order to improve catalytic activity. LaBO3 perovskite catalysts were modified by substitution of Co by Fe and Mn. The catalytic activity of LaCoO3 improved due to partial substitution of Co by Fe and Mn cations. LaCo0.7Mn0.3O3 showed the highest catalytic activity among the synthesized catalysts. The structures and morphology of synthesized perovskites were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The results of X-ray diffraction indicated that the LaBO3 and LaCo0.7B′0.3O3 samples obtained using sol-gel method had a pure perovskite-type crystal structure.
Reaction Engineering, Kinetics and Catalysts,
Volume 8, Issue 2 , April 2011, , Pages 69-80
M.H. Akbari; M. Rahimi; H.R. Karami
Abstract
Decreasing pressure losses in microtubes is an important subject, especially when increase in flow capacity is required. In the same pumping power, decreasing the pressure drops is coincides with increasing the fluid flow rate passing through a microtube. The current study aims to examine how the water ...
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Decreasing pressure losses in microtubes is an important subject, especially when increase in flow capacity is required. In the same pumping power, decreasing the pressure drops is coincides with increasing the fluid flow rate passing through a microtube. The current study aims to examine how the water pressure drop across a microtube can be affected by the addition of small concentrations of different drag-reducing polymeric agents. A kind of laminarization behaviour was found by the addition of the selected polymer to the turbulent flow. The effect of concentration of drag-reducing agent (DRA) on observed viscosity and drag values are reported. Moreover, the effects of different types of drag-reducing agents on friction factor are obtained at the best concentration in the range of examined concentrations. Under this condition amount of drag reduction percentage and increase in capacity of the flow were respectively 33% and 36%. The obtained results show that more drag reduction occurs at a higher flow rate for 20ppm of high molecular weight polyacrylamide.