Reaction Engineering, Kinetics and Catalysts,
B. Mokhtarani; S. Babaei; H.R. Mortaheb; K. Tabar Heidar
Volume 13, Issue 2 , April 2016, , Pages 71-79
Abstract
Polycyclic aromatic hydrocarbons (PAH) are toxic, mutagenic, and carcinogenic compounds. Removal of these compounds has a great importance for environment. Removal of PAHs from soil is difficult as these chemicals are persistent in the soil. In this research, bioremediation of soil contaminated by (PAH) ...
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Polycyclic aromatic hydrocarbons (PAH) are toxic, mutagenic, and carcinogenic compounds. Removal of these compounds has a great importance for environment. Removal of PAHs from soil is difficult as these chemicals are persistent in the soil. In this research, bioremediation of soil contaminated by (PAH) using Bacillus subtilis DSMZ 3256 (B.subtilis) strains was studied. The effect of electrokinetic on biodegradation of PAH was investigated. Fluorene and phenanthrene were selected as PAH and were mixed with soil. The bioremediation experiment was initially performed at 30oC and different humidities. The results represented 12.2 and 11.9% removal of fluorene and phenanthrene at 40% relative humidity after 7 days, respectively. The effects of electrokinetic on this process were studied at different current densities. It was found that the electrokinetic can reduce the biodesulfurization time. According to the results, the removal percents of fluorene and phenanthrene after 4 days under current density 1.82 mA/cm2 were 39.4 and 37.2, respectively.
Transport Phenomena,
Volume 6, Issue 3 , July 2009, , Pages 71-87
Abstract
In this study, we examined a scale-up to production of nickel perovskite catalyst, used in the conversion of natural gas to synthesis gas, using the sol-gel method in the laboratory and a bench-scale reactor. The required volume of solvent and catalyst activity in the methane-reforming reaction was determined ...
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In this study, we examined a scale-up to production of nickel perovskite catalyst, used in the conversion of natural gas to synthesis gas, using the sol-gel method in the laboratory and a bench-scale reactor. The required volume of solvent and catalyst activity in the methane-reforming reaction was determined from the optimum catalyst production conditions at the laboratory scale. This information was then used to design the bench-scale unit. We used heat-transfer models in a non-continuous bench reactor and scale-up fundamentals to achieve the same physical and chemical properties of the catalyst as that in the laboratory sample. A correlation coefficient corresponding to the experiment conditions, including the stirrer geometry, is presented based on the heat transfer equations in stirred tanks. This correlation can be used to estimate the heattransfer coefficient at larger scales, such as in a pilot reactor.
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.
Polymer Engineering and Technology,
F. Ader; E. Sharifzadeh
Abstract
In this study, the main purpose has been to investigate the behavior of the nanoparticles with different structures and similar based materials in polymer nanocomposites. To this end, different samples, containing PS as the matrix, and layered graphene oxide (GO) and/or hollow graphene oxide nanoparticles ...
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In this study, the main purpose has been to investigate the behavior of the nanoparticles with different structures and similar based materials in polymer nanocomposites. To this end, different samples, containing PS as the matrix, and layered graphene oxide (GO) and/or hollow graphene oxide nanoparticles (HGO), were prepared via the melt mixing process and were subjected to heat conduction and tensile tests. To evaluate all features of the interaction between the polymer phase and the nanoparticles, a thermal/mechanical analytical model was proposed and the results were used to simulate the behavior of specific geometrical structures, corresponding to the real samples, under different thermal/mechanical conditions. The results showed good agreement between the obtained experimental data and simulation/analytical model interpretations. In addition, it was found that the HGO nanoparticle had such a good performance in enhancing the thermal and mechanical properties of the nanocomposite, due to its unique structure.
Modeling and Simulation
M. Fakhroleslam; A. Samimi; S.A. Mousavi; R. Rezaei
Volume 13, Issue 1 , January 2016, , Pages 73-83
Abstract
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 ...
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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
Modeling and Simulation
Volume 7, Issue 3 , July 2010, , Pages 74-80
Polymer Engineering and Technology,
M. Fasihi; R. Arabzadeh; M.R. Moghbeli
Volume 14, Issue 2 , 2017, , Pages 74-82
Abstract
The aim of this study was to improve the adhesion performance of plasticized polyvinyl chloride (PVC) coatings on steel substrates by using nanoparticles. For this purpose, the PVC plastisol with different concentration of nano-silica was prepared and applied to bond steel joints. The adhesive strength ...
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The aim of this study was to improve the adhesion performance of plasticized polyvinyl chloride (PVC) coatings on steel substrates by using nanoparticles. For this purpose, the PVC plastisol with different concentration of nano-silica was prepared and applied to bond steel joints. The adhesive strength of the joints was determined by single-lap shear test. Moreover, mechanical properties and microstructure of coating were investigated. The addition of 1wt% nano-silica to plastisol dramatically increased the lap shear strength up to 4-fold, which was an outcome of compatibilizing effect of silica. Young's modulus and tensile strength of plasticized PVC were slightly increased by adding nanoparticles, as well. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) exhibited higher inclusion size in the coating having higher silica volume which was attributed to the agglomeration of nanoparticles. In the following, the effect of plasticizer composition on the adhesion strength by replacing some part of dioctyl phthalate (DOP) plasticizer with more polar oil, epoxidized soybean oil (ESO), was examined. Although adding ESO improved the lap shear strength of the neat coating, its effect on the properties of the coatings containing silica was negligible.
Separation Technology,
Saeed Ovaysi
Abstract
A new approach is proposed to evaluate various designs for gas-solid cyclone separators. This approach uses single-phase flow simulation results to find a quantitative measure of flow symmetry in a given cyclone. Flow symmetry is computed by averaging imbalances of non-axial velocities ...
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A new approach is proposed to evaluate various designs for gas-solid cyclone separators. This approach uses single-phase flow simulation results to find a quantitative measure of flow symmetry in a given cyclone. Flow symmetry is computed by averaging imbalances of non-axial velocities throughout the cyclone. Using this approach, two standard design methods are evaluated and the cyclone with a more symmetric flow pattern is chosen as a starting point for further design improvements by reducing the diameter of its vortex finder. Two-phase computational fluid dynamics (CFD) simulations compute 90.2 % collection efficiency for the improved design. CFD simulations reveal using a cascade of four cyclones results in an overall 99.98 % collection efficiency. Once installed in the actual industrial setting, the cyclone cascade achieves a 98.56 % collection efficiency and a particle size distribution which is in good agreement with CFD computed results.
Transport Phenomena,
Volume 7, Issue 1 , January 2010, , Pages 76-86
Modeling and Simulation
Hadi Soltani; Sirous Shafiei
Volume 12, Issue 3 , July 2015, , Pages 77-95
Abstract
In this study a new and robust procedure is presented to solve synthesis of isothermal reactor networks (RNs) which considers more than one objective function. This method uses non-dominated sorting genetic algorithm II (NSGAII) to produce structural modification coupled with quasi linear programming ...
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In this study a new and robust procedure is presented to solve synthesis of isothermal reactor networks (RNs) which considers more than one objective function. This method uses non-dominated sorting genetic algorithm II (NSGAII) to produce structural modification coupled with quasi linear programming (LP) method for handling continuous variables. The quasi LP consists of an LP by adding a search loop to find the best reactor conversions as well as split and recycle ratios which are much easier to solve. To prevent complexity and ensure optimum solution, only ideal continuous stirred tank reactors (CSTRs), plug flow reactors (PFRs) and PFR with recycle stream are considered in producing reactor networks. Also, to avoid differential equations which appear in design equations of PFR reactors, CSTRs in series are replaced for each PFR. Results show that the proposed method finds better solutions than those reported in the literature.
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
N. Hajilary; S. Hashemi; M. Hajiabadi
Abstract
MXene membranes perform well in biofuel separation due to their excellent hydrophilicity, flexibility, and mechanical strength. For the first time, computational fluid dynamics was used to model the dehydration of ethanol through the pervaporation system by the MXene membrane. We discretized the momentum ...
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MXene membranes perform well in biofuel separation due to their excellent hydrophilicity, flexibility, and mechanical strength. For the first time, computational fluid dynamics was used to model the dehydration of ethanol through the pervaporation system by the MXene membrane. We discretized the momentum and continuity equations using finite element methods and predicted the mass transport. Experimental results and model data were in good agreement (less than 10 %). The feed velocity, feed concentration, and membrane thickness all had positive effects on the separation factors while the temperature had a decreasing effect. This model's efficiency has decreased by 35 % after increasing the feed flow rate by 10 times. In addition, the separation factor increases tenfold when temperature is raised from 25 to 70 °C.
Polymer Engineering and Technology,
Volume 11, Issue 2 , April 2014, , Pages 78-91
Modeling and Simulation
k. movagharnejad; F. Saffar
Volume 15, Issue 2 , May 2018, , Pages 78-90
Abstract
In the present research, three different architectures were investigated to predict the coefficients of the Daubert and Danner equation for calculation of saturated liquid density. The first architecture with 4 network input parameters including critical temperature, critical pressure, critical volume ...
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In the present research, three different architectures were investigated to predict the coefficients of the Daubert and Danner equation for calculation of saturated liquid density. The first architecture with 4 network input parameters including critical temperature, critical pressure, critical volume and molecular weight, the second architecture with 6 network input parameters including the ones in the first architecture with acentric factor and compressibility factor. The third architecture contains 12 network input parameters including 6 input parameters of the second architecture and 6 structural functional groups of different hydrocarbons. The three different architectures were trained and tested with the 160 sets of Daubert and Danner coefficients gathered from the literature. The trained neural networks were also applied to 15 un-known hydrocarbons and the outputs (Daubert and Danner coefficients) were used to predict the saturated liquid densities. The calculated liquid densities were compared with the experimental values. The Results indicated that the coefficients obtained from the second architecture produced more precise values for the liquid densities of the 15 selected hydrocarbons.
Separation Technology,
B. Medi; M.-K. Kazi
Volume 15, Issue 4 , November 2018, , Pages 81-92
Abstract
In this work, an improved single-column chromatographic (ISCC) separation process is proposed. The term `improved' refers to both conceptual and physical modifications compared to the available single-column processes, including a novel fraction collection scheme and allowing overlapped peaks from adjacent ...
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In this work, an improved single-column chromatographic (ISCC) separation process is proposed. The term `improved' refers to both conceptual and physical modifications compared to the available single-column processes, including a novel fraction collection scheme and allowing overlapped peaks from adjacent cycles. Also the fraction collection mechanism was modified in order to facilitate online monitoring. Another advantage of the ISCC process is its large degree of freedom as injection volume, cycle time, solvent flow rate, feed concentration, and fraction-collection intervals can all be decision variables in this process. The experimental implementation and validation is covered in this work. The results indicate successful operation of the ISCC process and accompanying peripherals for the separation of guaifenesin enantiomers. In particular, the tests confirmed the integrity of the online monitoring system and proved the capability of the process for 98% purification of the tested enantiomers with an advantageously shorter cycle time, which results in higher productivity.
Modeling and Simulation
A. Abdi; M.Sh Izadkhah; A. Karimi; M. Razzaghi; H. Moradkhani
Volume 15, Issue 3 , September 2018, , Pages 82-93
Abstract
A three-layer artificial neural network (ANN) model was developed to predict the remained DO (deoxygenation) in water after DO removal with an enzymatic granular biocatalyst (GB), based on the experimental data obtained in a laboratory stirring batch study. The effects of operational parameters such ...
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A three-layer artificial neural network (ANN) model was developed to predict the remained DO (deoxygenation) in water after DO removal with an enzymatic granular biocatalyst (GB), based on the experimental data obtained in a laboratory stirring batch study. The effects of operational parameters such as initial pH, initial glucose concentration and temperature on DO removal were investigated. On the basis of batch reactor test results, the optimum value of operating temperature, glucose concentration and pH were found to be 30oC, 80 mM and 7, respectively. After back-propagation training, the ANN model was able to predict the remained DO with a tangent sigmoid function (tansig) at hidden layer with 7 neurons and a linear transfer function (purelin) at the output layer. The linear regression between the network outputs and the corresponding targets were proven to be satisfactory with a correlation coefficient of 0.995 for three model variables used in this study.
Reaction Engineering, Kinetics and Catalysts,
Mohammad Pazouki; Ali Zakeri; Manoucher Vossoughi
Volume 12, Issue 4 , October 2015, , Pages 84-92
Abstract
In this research, unstructured kinetic modeling for cell growth evaluation by X.campestris, xanthan production and sugar cane molasses consumption in a batch culture were investigated. Logistic model for biomass growth, Luedeking-Piret model for xanthan biopolymer production and modified Luedeking-Piret ...
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In this research, unstructured kinetic modeling for cell growth evaluation by X.campestris, xanthan production and sugar cane molasses consumption in a batch culture were investigated. Logistic model for biomass growth, Luedeking-Piret model for xanthan biopolymer production and modified Luedeking-Piret model for sugar cane molasses consumption provides an accurate prediction of the fermentation kinetics parameters with high coefficient of determination R2 values.Luedeking-Piret model for xanthan biopolymer production in three different concentration of sugar cane molasses (30, 60 and 90 g/l) as the sole carbon source substrate were studied. A good agreement between experimental and predicted values indicated that the unstructured models were able to describe this fermentation process successfully. The values of specific growth rate μ_max of logestic model for sugar cane molasses (30, 60 and 90 g/l) were 0.029, 0.031 and 0.032 h-1 respectively. The values of α and β is 5.280, 6.594, 8.518 and 0.072, 0.066, 0.086 respectively which shows that the xanthan production is growth associated since the value of the growth associated parameter α is much more than the value of nongrowth associated parameter β in Luedeking Piret model. Moreover, the values of γ and 𝜂 in modified Luedeking-Piret model were obtained.
M. Asadollahi
Volume 16, Issue 3 , September 2019, , Pages 84-92
Abstract
Although two-phase flow is frequently encountered in various location of the process plants, there is no a general accepted and verified two-phase flow model that may be used to size lines for such conditions. An obvious example is condensate water return lines. The API method that used in this study ...
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Although two-phase flow is frequently encountered in various location of the process plants, there is no a general accepted and verified two-phase flow model that may be used to size lines for such conditions. An obvious example is condensate water return lines. The API method that used in this study is based on the homogeneous equilibrium flow assumption, that is, equal velocity and equal temperature in both liquid and vapor phases. Also, DIERS method has used to verify and clarify the HEM approach to calculate the pressure drop in two phase regimes. The objective of this study is to introduce a solution for process lines design during different flashing scenarios. In this work by applying API method we can find the two-phase line pressure drop and upstream pressure while by using DIERS method we would be able to realize that for a specified length of pipe how much two phase flow could pass through when the pressure drop is just same as the API model.
Separation Technology,
A. Saberimoghaddam; V. Khebri
Volume 15, Issue 1 , February 2018, , Pages 89-101
Abstract
One of the most appropriate methods for elimination of trace impurities in helium is cryogenic adsorption process. So, in this study design and construction of cryogenic adsorption helium purification system (3 Nm3.hr-1, 80 bar) carried out using activated carbon as adsorbent at 77K. To evaluation of ...
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One of the most appropriate methods for elimination of trace impurities in helium is cryogenic adsorption process. So, in this study design and construction of cryogenic adsorption helium purification system (3 Nm3.hr-1, 80 bar) carried out using activated carbon as adsorbent at 77K. To evaluation of adsorption dynamics and effect of pressure on elimination of trace impurities, helium purification was performed from 10 to 70 bar. Results showed that helium can be purified from 99.95 % to 99.99999% at pressure of 60 bar using cryogenic adsorption process. Effect of regeneration condition on helium purity and recovery was investigated by three different regeneration methods: regeneration by helium at 40 °C and at 180 °C as purge gas, countercurrent to feed direction, and regeneration via vacuum. Results showed that regeneration of bed by vacuum can be proposed as most appropriated method because of maximum helium purity and high recovery of helium (98%).
Materials synthesize and production
R. Ahmadi; H. Sanaeepur; A. Ebadi Amooghin
Abstract
It is crucial to design and develop new polymers with desirable characteristics. Aromatic polyimides have been attracted more attention in comparison with other polymeric materials, because of their excellent properties, such as the high thermal stability, mechanical strength, and chemical resistance. ...
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It is crucial to design and develop new polymers with desirable characteristics. Aromatic polyimides have been attracted more attention in comparison with other polymeric materials, because of their excellent properties, such as the high thermal stability, mechanical strength, and chemical resistance. In this work, two semi-aromatic polyimides (BCDA-mPDA and BCDA-Durene) were successfully synthesized from bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarbocylic dianhydride (BCDA), 1,3-phenylenediamine (mPDA), and 2,3,5,6-tetramethyl-1,4-phenylenediamine (Durene) to investigate the effect of methyl functional groups on the physicochemical and structural properties of the synthesized polyimides. The synthesized polyimides were characterized by the proton nuclear magnetic resonance (1H-NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, inherent viscosity measurement, and solubility test. FTIR and 1H-NMR results confirmed the chemical structure of the synthesized polyimides. XRD results showed that the presence of bulky methyl groups has led to increasing amorphous regions in the polymer structure. In addition, these new polymers were soluble in various organic solvents such as dimethylformamide (DMF), dimethylsulfoxide (DMSO), and N-methyl-2-pyrrolidone (NMP). The inherent viscosity of the synthesized polyimides was 0.65 dl/g for BCDA-Durene and 0.96 dl/g for BCDA-mPDA, which indicates the moderate molecular weight of the polymers.
Materials synthesize and production
A. jafarizad; H. Hazrati; A.M. Jabbari
Volume 16, Issue 2 , June 2019, , Pages 95-102
Abstract
In this work, for eliminating the (RR1346), considered to be a waste in wastewater from dye industries electrochemical advanced oxidation process has been used. Graphene oxide coated carbon cloth (GO/CC) and Fe3O4 /GO coated carbon cloth (Fe3O4/GO/CC) electrodes has been fabricated by synthesized GO ...
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In this work, for eliminating the (RR1346), considered to be a waste in wastewater from dye industries electrochemical advanced oxidation process has been used. Graphene oxide coated carbon cloth (GO/CC) and Fe3O4 /GO coated carbon cloth (Fe3O4/GO/CC) electrodes has been fabricated by synthesized GO and Fe3O4 nanoparticles. Characteristic properties such as surface morphology as the main reason of utilizing Fe2O3/GO/CC as electrodes has been investigated determined by various instrumental analysis including, Atomic Force Microscopy (AFM), Field Emission Scanning Electron Microscopy (FESEM), Cyclic Voltammetry (CV), Cathodic polarization, and also for investigating the process yield by utilization of mentioned electrodes, UV-vis spectrophotometric analysis has been used to determine dye concentration in sample waste water, after comparing fabricated electrodes removal efficiency in same time intervals, by determining the concentration of RR1346 dye in samples after oxidation process in different time intervals, results indicated better removal efficiency Fe3O4/GO/CC fabricated electrode than the other two electrodes, which this conclusion was proved by AFM,FESEM and UV-vis results.
Modeling and Simulation
M. Bahoosh; E. Kashi; S. Shokrollahzadeh; Kh. Rostami
Volume 16, Issue 1 , March 2019, , Pages 101-116
Abstract
Reverse osmosis is a commonly used process in water desalination. Due to the scarcity of freshwater resources and wastewater problems, a lot of theory and experimental studies have been conducted to optimize this process. In the present study, the performance of reverse osmosis membrane module of salt–water ...
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Reverse osmosis is a commonly used process in water desalination. Due to the scarcity of freshwater resources and wastewater problems, a lot of theory and experimental studies have been conducted to optimize this process. In the present study, the performance of reverse osmosis membrane module of salt–water separation was simulated based on computational fluid dynamics technique and solution-diffusion theory. Eight geometries of membrane modules four flat sheets, and four tubular membranes were investigated. It was found that if the membrane surface area and inlet flow rate were kept constant for the eight modules, the pressure drop and permeated flow rate would be approximately similar for some geometries (such as the performance of primary flat sheet channel is same as 3 tubular membranes with R=1/3 Rref). The results also showed that because of the phenomenon of concentration polarization, if it is possible to use more membranes with a smaller length, it can reduce the pressure drop and increase the permeation flux of water. Furthermore, the results showed that in similar conditions between the tubular and the plate membranes; the tubular one is more suitable for the water permeation due to its ease of construction and its ability to withstand ECP.
Modeling and Simulation
Yaser Kazemi; Abdullah Irankhah
Abstract
Most of the reactions that occur in microreactors take place on the surface, so it is important to keep the reactants close to the reactive wall. One effective technique in this field is single-phase hydrodynamic focusing. However, this method has a drawback: a high percentage of reactants penetrate ...
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Most of the reactions that occur in microreactors take place on the surface, so it is important to keep the reactants close to the reactive wall. One effective technique in this field is single-phase hydrodynamic focusing. However, this method has a drawback: a high percentage of reactants penetrate into the sheath fluid. To address this issue, the concept of two-phase hydrodynamic focusing is introduced in this study. The main idea is to use a highly viscous sheath fluid to create a barrier against reactant penetration into the sheath flow. To demonstrate the effectiveness of this method, a 3D numerical simulation was performed with an irreversible second-order reaction. The results show that two-phase hydrodynamic focusing increases reaction rates, particularly in downstream regions where the Sherwood number can increase by several orders of magnitude with the use of a highly viscous sheath of liquid. Additionally, it was observed that the use of two-phase hydrodynamic focusing improves efficiency, which is defined as the ratio of solute in the sample flow to the total solute in each cross-section.
Modeling and Simulation
Volume 1, Issue 2 , July 2004, , Pages 55-70
Abstract
SHAHAB is a PC- based simulator developed by Olefin Research Group (ORG), with the simultaneous simulation of the reactor, the firebox, the convection section and the transfer line exchanger in steam Cracking units. The reaction mechanism of thermal cracking of hydrocarbons is generally accepted as free-radical ...
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SHAHAB is a PC- based simulator developed by Olefin Research Group (ORG), with the simultaneous simulation of the reactor, the firebox, the convection section and the transfer line exchanger in steam Cracking units. The reaction mechanism of thermal cracking of hydrocarbons is generally accepted as free-radical chain reactions. Using a rigorous kinetic model, a complete reaction network for representing the decomposition of hydrocarbon feedstocks has been developed and used for simulation of thermal hydrocarbon crackers. Taking into account the kinetics of coke formation, SHAHAB provides a detailed understanding of product, temperature and pressure distribution, coke thickness profile, reactor run length, fuel consumption and the amount of steam generated.
Petroleum and Reservoir Engineering
Volume 8, Issue 1 , January 2011, , Pages 56-65