Modeling and Simulation
Volume 3, Issue 1 , January 2006, , Pages 52-64
Modeling and Simulation
Volume 3, Issue 2 , April 2006, , Pages 52-63
Modeling and Simulation
Volume 2, Issue 1 , January 2005, , Pages 52-60
Abstract
n this paper, a mathematical model has been derived to predict the granulation time of anaerobic sludge in UASB reactors. In the proposed model, some physical, chemical and biological parameters affecting the granulation phenomena have been considered. To validate the model, 12 pilot-scale experiments ...
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n this paper, a mathematical model has been derived to predict the granulation time of anaerobic sludge in UASB reactors. In the proposed model, some physical, chemical and biological parameters affecting the granulation phenomena have been considered. To validate the model, 12 pilot-scale experiments in 4 UASB reactors are carried out and the results are discussed here. The reactors are started up at different environmental conditions and the granulation time in each experiment is determined. The results show that the model is able to explain different mechanisms involved in the granulation process.
Reaction Engineering, Kinetics and Catalysts,
Z. Alihemati; A.H Navarchian
Volume 14, Issue 1 , March 2017, , Pages 52-66
Abstract
This study presents the synthesis of polyvinyl acetate (PVAc) by solution polymerization and its partial hydrolysis to polyvinyl alcohol (PVA) using alkaline alcoholysis. The influence of the molar ratio of hydrolysis catalyst (NaOH) to PVAc and the time and temperature of the saponification reaction ...
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This study presents the synthesis of polyvinyl acetate (PVAc) by solution polymerization and its partial hydrolysis to polyvinyl alcohol (PVA) using alkaline alcoholysis. The influence of the molar ratio of hydrolysis catalyst (NaOH) to PVAc and the time and temperature of the saponification reaction on the degree of hydrolysis and molecular weight of the PVA were investigated using response surface methodology. Statistical analysis of the results revealed that the degree of hydrolysis and molecular weight of PVA were strongly dependent on the molar ratio of NaOH/PVAc. It was also found that the second-order interactions between the investigated parameters were not statistically significant. The optimal conditions for synthesizing PVA as a primary suspending agent were obtained as T = 45°C, t = 33 min and NaOH/PVAc (molar ratio) = 0.05. The chemical structures of the PVAc and the optimum PVA were studied by Fourier transform infrared spectroscopy. The distribution of acetate groups in the optimum PVA was determined using 13C nuclear magnetic resonance spectroscopy. It was found that addition of benzene as well as one-step addition of NaOH (when compared with drop-wise addition) result in more blockiness in the acetate group distribution of PVA. The performance of the optimum PVA was also investigated for a typical suspension polymerization of vinyl chloride and the particle morphology of the product was studied using scanning electron microscopy.
Reaction Engineering, Kinetics and Catalysts,
Pachaiyappan Abimannan; Venugopal Rajendran
Volume 13, Issue 3 , July 2016, , Pages 54-62
Abstract
In this paper, we report the reaction of isoamyl alcohol and 1-chloro-4-nitrobenzene was carried out in a batch reactor under aqueous-organic biphasic conditions using the techniques like phase transfer catalysis and ultrasound irradiation. Tetrabutylammonium bromide (TBAB) was employed as the phase ...
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In this paper, we report the reaction of isoamyl alcohol and 1-chloro-4-nitrobenzene was carried out in a batch reactor under aqueous-organic biphasic conditions using the techniques like phase transfer catalysis and ultrasound irradiation. Tetrabutylammonium bromide (TBAB) was employed as the phase transfer catalyst. The reaction is greatly enhanced by adding a small quantity of phase-transfer catalyst under ultrasound (28 kHz, 300W). Detailed kinetics of the etherification was investigated. The rate constants were determined by varying the concentration of the catalyst, stirring speed, the concentration of alcohols, temperature, different solvents, concentration of sodium hydroxide, different inorganic salts and different phase transfer catalysts. From the detailed kinetic study, the optimum reaction conditions to produce higher yield of 1-(isopentyloxy)-4-nitrobenzene was obtained. The experimental data were well described by the pseudo-first-order equation. The individual experiment was carried without ultrasound; the obtained kapp value is 0.0094 min-1. The combination of ultrasound and stirring; the kapp value is 0.0178 min-1. From the observed results, the kapp value for ultrasonically promoted reaction is almost two fold higher than the normal reaction.
Reaction Engineering, Kinetics and Catalysts,
Volume 11, Issue 1 , January 2014, , Pages 55-62
Separation Technology,
Volume 10, Issue 4 , October 2013, , Pages 55-64
Biomedical and Biotechnology,
Volume 10, Issue 2 , April 2013, , Pages 55-66
Transport Phenomena,
Volume 10, Issue 1 , January 2013, , Pages 55-66
Petroleum and Reservoir Engineering
D. C. Panadare; V. K. Rathod*
Volume 12, Issue 3 , July 2015, , Pages 55-76
Abstract
Waste cooking oil (WCO) is being generated large scale all over the world; hence it has devised serious problems of its waste management. Organised collection of WCO in voluminous quantity is mainly used for the production of biodiesel. Most researchers focus primarily on the biodiesel generation from ...
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Waste cooking oil (WCO) is being generated large scale all over the world; hence it has devised serious problems of its waste management. Organised collection of WCO in voluminous quantity is mainly used for the production of biodiesel. Most researchers focus primarily on the biodiesel generation from WCO, although other applications are also important and require attention. Objective of this review article is to highlight most of the aforementioned possible applications of WCO which may help in its utilization apart from biodiesel. It can be processed to obtain pyrolytic oil, hydrogen gas, biodiesel or electricity production by direct burning. Applications like combined heat and power generation (CHP) can utilize WCO with utmost efficiently. It can also be processed chemically to obtained biodegradable polyurethane sheets, greases, biolubricants, soaps and alkyd resins. Properly purified and sterilized WCO can be used as a carbon source in fermentation processes for the production of rhamnolipid biosurfactant and polyhydroxybutyrate (PHB). Waste cooking oil therefore can be considered as a potential waste which can be utilized as energy source and raw material for chemical or biological processes.
Thermodynamics,
Volume 5, Issue 2 , April 2008, , Pages 55-63
Abstract
"> Phase inversion phenomenon occurs in many industrial processes including liquidliquid dispersions. Some parameters such as energy input or the presence of mineral compounds in the system affect this phenomenon. The aim of this research is to study the speed of rotation or energy input at a range ...
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"> Phase inversion phenomenon occurs in many industrial processes including liquidliquid dispersions. Some parameters such as energy input or the presence of mineral compounds in the system affect this phenomenon. The aim of this research is to study the speed of rotation or energy input at a range of 400 to 800 rpm in a batch liquid-liquid system containing toluene and water. The presence of sodium chloride and magnesium sulphate in the system was also studied. It was shown that the increase of energy input had a more obvious effect on oil in water (O/W ) dispersion at lower values of holdup. It was also shown that the ambivalence (o/w → w/o) region of the phase inversion curve shifted downward and became wider as a result of the decrease in interfacial tension. It was observed that inorganic salt, used in both single and dual (mixed) shapes, enhanced phase inversion for O/W dispersion. Therefore, the greater the ionic strength of salt, the greater the tendency to phase inversion is.
Modeling and Simulation
A. Parvareh; . Parvizi
Volume 14, Issue 3 , August 2017, , Pages 55-64
Abstract
Abstract In this work, the role of appropriate mixing for mercaptan removal from Kerosene using caustic soda has been investigated in the pilot scale. Static mixer at different condition has been used as a passive mixing tool to achieve proper mixing and consequently high performance of mercaptan removal. ...
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Abstract In this work, the role of appropriate mixing for mercaptan removal from Kerosene using caustic soda has been investigated in the pilot scale. Static mixer at different condition has been used as a passive mixing tool to achieve proper mixing and consequently high performance of mercaptan removal. Two lengths of static mixer including 20 and 40 cm as well as two pitches 1 and 3 mm were considered in a straight line. NaOH was injected to the Kerosene line to remove ( convert it to disulfide) the mercaptan. The effect of mixer length, mixer element pitch at different flow rates of Kerosene, including 2, 18 and 30 mL/s was investigated on the mercaptan removal. The experimental results showed that the concentration of mercaptan in the pilot line outlet will decrease as the flow rates of Kerosene decreases. Also, at a fixed flow rate of Kerosene, increasing the length of the static mixer and decreasing its element pitch caused the mercaptan to decrease due to proper mixing. Computational Fluid Dynamics (CFD) modeling technique was employed to describe the experimental results, fluid flow pattern, and mixing performance. Qualitative predicted results of CFD modeling show a good agreement with the experimental data.
Modeling and Simulation
Volume 11, Issue 2 , April 2014, , Pages 56-77
H. Rezaei; S. Ovaysi; M. Rahimi
Abstract
The objective of the investigation was to mathematically correlate the behavior of a supersonic superheated steam flow inside a Laval nozzle, against the decision parameters. The decision parameters are the inlet temperature ranging from 374.3 K to 504.3 K and the inlet pressure from 40050.14 Pa to 133375.7 ...
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The objective of the investigation was to mathematically correlate the behavior of a supersonic superheated steam flow inside a Laval nozzle, against the decision parameters. The decision parameters are the inlet temperature ranging from 374.3 K to 504.3 K and the inlet pressure from 40050.14 Pa to 133375.7 Pa. Indeed, the outlet temperature, outlet pressure as well as the Mach number are mathematically correlated against the decision parameters. The numerical approach based on the Computational Fluid Dynamics (CFD) is selected to study the behavior of the supersonic superheated steam flow inside the nozzle. By examining the different temperature and pressure conditions of the inlet fluid, it was found that the closest distance from the starting point of condensation to the throat is at the highest pressure and lowest temperature. Conversely, the farthest distance from the starting point of condensation to the throat is at the lowest pressure and highest temperature. In addition, three mathematical correlations were developed. Due to the high accuracy of the mathematical correlations, the efficiency of the predictor models in predicting the outputs was proved.
Biomedical and Biotechnology,
Volume 8, Issue 2 , April 2011, , Pages 57-68
Transport Phenomena,
Volume 6, Issue 3 , July 2009, , Pages 57-70
Abstract
In this paper, the experimental data of the onion drying process by a batch cabinet dryer is investigated. Obtained experimental data including moisture content, shrinkage, and rehydration via random factorial scheme are analyzed. Comparison of data average is carried out with the help of the multi amplitude ...
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In this paper, the experimental data of the onion drying process by a batch cabinet dryer is investigated. Obtained experimental data including moisture content, shrinkage, and rehydration via random factorial scheme are analyzed. Comparison of data average is carried out with the help of the multi amplitude test of Duncan. Statistical analysis of experimental data shows that time, temperature, and their combined effect have a reasonable impact on the moisture content and rehydration value of dried samples. However, a combined effect of time and temperature on the shrinkage value is not meaningful (P>0.05). The results also show that increasing time and temperature leads to a decrease in the moisture content of the samples, but it increases the value of rehydration and the shrinkage of samples.
Transport Phenomena,
Sh. Ghodbanan; R. Alizadeh; S. Shafiei
Volume 13, Issue 2 , April 2016, , Pages 57-70
Abstract
In this study a developed model has been used to evaluate the paper drying process and examine the pocket dryer conditions of a multi-cylinder fluting paper machine. The model has been developed based on the mass and energy balance relationships in which the heat of sorption and its variations with paper ...
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In this study a developed model has been used to evaluate the paper drying process and examine the pocket dryer conditions of a multi-cylinder fluting paper machine. The model has been developed based on the mass and energy balance relationships in which the heat of sorption and its variations with paper temperature and humidity changes have been taken into account. The applied model can be used to compute the drying parameters and analyze the pocket drying conditions. Furthermore, the effects of web tension on the heat transfer have been investigated. In the available operating range of the web tension, the overall mean heat transfer coefficient will be within 300-550 W/m2.K. The pocket air temperature was between 50 and 90 oC. The dew point temperature wasn’t close to the pocket air temperature and dew drop never happened during the dryer section. Based on the modeling result and using a novel technique, the maximum level for the exhaust air in the studied machine can be estimated to be 0.2 kg H2O/kg dry air. Result shows that increasing the exhaust humidity to the optimal level will lead to 4% reduction in the required energy and 20% rise in the heat recovery potential. Accordingly the specific heat consumption per evaporated water for the studied drying section can be reduced from 3.96 to 3.81 GJ per ton water.
Biomedical and Biotechnology,
M. Saeedi; O. Vahidi
Volume 14, Issue 4 , December 2017, , Pages 59-79
Abstract
In this paper, we simulate magnetic hyperthermia process on a mathematical phantom model representing cancer tumor and its surrounding healthy tissues. The temperature distribution throughout the phantom model is obtained by solving the bio-heat equations and the consequent cell death amount is calculated ...
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In this paper, we simulate magnetic hyperthermia process on a mathematical phantom model representing cancer tumor and its surrounding healthy tissues. The temperature distribution throughout the phantom model is obtained by solving the bio-heat equations and the consequent cell death amount is calculated using correlations between the tissue local temperature and the cell death rate. To have an estimate of heat generated from typical magnetic nanoparticles, magnetite nanoparticles are synthesized and the heat dissipation amount from the synthesized nanoparticles exposed to an alternating magnetic field is measured and used in the computer simulation. The impact of the amount of heat generated from the magnetic nanoparticles exposed to an alternating magnetic field, their distribution patterns in the tumor and hyperthermia process duration time on the cell death rate in both cancer and healthy tissues are investigated. It is indicated that while various factors contributing in the heat dissipation amount from the magnetic nanoparticles are important in the effectiveness of the magnetic hyperthermia process, the distribution pattern plays the major role in determining the efficiency of the process.
Separation Technology,
M. Delavar; Gh. Bakeri; M. Hosseini
Volume 14, Issue 2 , 2017, , Pages 59-73
Abstract
In this study, novel polycarbonate-titanium oxide nanotubes (PC-TNT) ultrafiltration mixed matrix membranes (MMMs) were fabricated for decontamination of Cd2+ and Cu2+ metal ions from aqueous solution. The weight percent of TNTs in the polycarbonate membrane matrix was changed from 0 to 15. The synthesized ...
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In this study, novel polycarbonate-titanium oxide nanotubes (PC-TNT) ultrafiltration mixed matrix membranes (MMMs) were fabricated for decontamination of Cd2+ and Cu2+ metal ions from aqueous solution. The weight percent of TNTs in the polycarbonate membrane matrix was changed from 0 to 15. The synthesized neat PC membrane and PC-TNTs MMMs were characterized with respect to structural morphology and hydrophilicity using scanning electron microscopy (SEM) and water contact angle, respectively. The effects of TNTs loadings on the pure water flux, mean pore size, porosity and water contact angle of fabricated membranes and Cd2+ and Cu2+ heavy metal ion rejection were also studied. By increasing the loading of TNTs nanoparticles in the membrane matrix, the membrane mean pore size tended to increase, while the porosity decreased. Also, the increase in TNTs loading resulted in an increase in membrane water flux which was mainly attributable to the enhancement in mean pore size and partly caused by the decreased contact angle value (more hydrophilic). Of all the membranes studied, it was found by UF experiments that PC-TNT MMM was the most efficient material in heavy metal ions removal due to the superior adsorption capacity of TNTs material. The generic results revealed that TNTs material can be favorite candidates for MMMs preparation in order to be conveniently used in the Cd2+ and Cu2+ heavy metal ions decontamination from polluted water resources.
Polymer Engineering and Technology,
S. Ghazanchaie; F. Derakhshanfard; L. Amirkhani
Abstract
The synthesized polystyrene has weaknesses in terms of mechanical, physical and thermal properties which limit the use of this polymer. Therefore, the use of the mixtures of polymers can improve these properties. Different parameters like the mixing speed can affect the quality of the properties of the ...
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The synthesized polystyrene has weaknesses in terms of mechanical, physical and thermal properties which limit the use of this polymer. Therefore, the use of the mixtures of polymers can improve these properties. Different parameters like the mixing speed can affect the quality of the properties of the polymer being prepared from the mixture of several polymers. In this study, different percentages of nanocomposites in different stirring speeds have been added to polystyrene. Different tests have been performed on the prepared polymer and investigating the tests shows that in different stirring speeds the values of the tensile strength and impact resistance of the prepared polymer can be increased while the values of the Vicat Softening Temperature (vicat) and Melt Flow Index (MFI) test numbers remain constant. The obtained results from the laboratory data have been simulated by Artificial Neural Networks (ANNs) in order to predict the results for the points which have not been tested and the simulated results show that the laboratory data covered the simulated data perfectly. The results of tests show that by increasing nanoparticles, the resistance of the polymer against impacts will be increased and in addition, increasing the rate of the stirrer causes all other values of tests to increase.
Process Control and Engineering, Process Safety, HSE
A. Dehghan Lotfabad; S. Movahedirad; M.T. Sadeghi
Volume 13, Issue 1 , January 2016, , Pages 60-72
Abstract
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, ...
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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.
Transport Phenomena,
Volume 7, Issue 3 , July 2010, , Pages 61-73
Polymer Engineering and Technology,
Seyed Jamaleddin Peighambardoust; Ramin Faridvand; Abolfazl Shenavar
Volume 13, Issue 4 , November 2016, , Pages 62-70
Abstract
In this study, in-situ bulk polymerization was investigated for obtaining flame retardant polystyrene (PS). The halogenated and phosphoric compounds were used as flame retardant additives and Perkadox 30 was used as a synergist. The flammability of the PS was evaluated by thermogravimetric analyzer (TGA), ...
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In this study, in-situ bulk polymerization was investigated for obtaining flame retardant polystyrene (PS). The halogenated and phosphoric compounds were used as flame retardant additives and Perkadox 30 was used as a synergist. The flammability of the PS was evaluated by thermogravimetric analyzer (TGA), limiting oxygen index (LOI) and UL-94 tests. The results show that polymerization process for production of flame retardant polystyrene needs lower amount of flame retardant additives compare with the process for production of flame retardant composites. Furthermore, using Perkadox 30 as a synergist lowers the loading of flame retardant additives. LOI tests show that flame retardant polystyrene synthesized by adding at least 0.35 % (w/w) hexabromocyclododecane (HBCD) during polymerization. TGA analysis confirms that with addition of HBCD the degradation temperature decreases and weight loss occurs quickly. The degradation tempresure of the sample consist of 0.8 % (w/w) HBCD was lower than the sample consist of 0.35 % (w/w) HBCD and 0.45 % (w/w) triphenylphosphate (TPP). The pure polystyrene didn’t pass the UL-94 test because of inflammability and greater dripping. For samples with HBCD, shorter time needed to quench the flame and these samples passed the UL-94 test. On the other hand, greater dripping of polymer melt led to transmission of UL-94 rate from V0 to V2. It is also observed that flaming rate for samples with TPP was very low and dripping didn’t occur.
Separation Technology,
Sh. Biswas; Md. M. Islam; M. M. Hasan; S.H. Rimu; M. N. Khan; P. Haque; M. M. Rahman
Volume 15, Issue 4 , November 2018, , Pages 63-80
Abstract
This paper reports the evaluation of adsorbing Cr (VI) ions on sorbent prepared from chitosan (CHT), a versatile derivative of chitin, and dodecyl amine modified locally available kaolinite clay (Bijoypur clay) (MC) that has excellent mechanical properties and great resistance to chemical and biological ...
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This paper reports the evaluation of adsorbing Cr (VI) ions on sorbent prepared from chitosan (CHT), a versatile derivative of chitin, and dodecyl amine modified locally available kaolinite clay (Bijoypur clay) (MC) that has excellent mechanical properties and great resistance to chemical and biological attack. The effect of the initial metal ion concentration, solution pH, contact time, and adsorbent dosages on the adsorption capacity of the composites was investigated. pH 4 is selected for better adsorption by the adsorbents. The adsorption abilities were studied over Cr (VI) ions using different adsorption isotherm such as Langmuir, Freundlich, and Dubinin-Radushkevich respectively. Langmuir isotherm is found better fitted with maximum adsorption capacity of 73 mg/g by composite SB-1. R2 obtained from Langmuir isotherm is 0.999 which indicates a monolayer adsorption on the adsorbent surface. The adsorption kinetics was also well described by the pseudo-second-order equation with a rate constant of 0.000302 g mg−1 min−1 at 25 ppm Cr(VI) concentration. The adsorption of Cr (VI) ions by the adsorbent were confirmed by FT-IR and X-RD analysis of the composites before and after Cr (VI) ion adsorption. The desorption percentage of the metal ion and the second cycle metal adsorption by regenerated (regenerated after the first adsorption by fresh adsorbent) adsorbent processed with 0.01N sulphuric acid shows a value of 78.23% and 68.12% respectively.
Reaction Engineering, Kinetics and Catalysts,
Gholamreza Moradi; Hamed Hemmati; Sahar rostami
Abstract
In this work, the effect of the Si/Al ratio on the activity of zeolite supported bimetallic (Ni-Co) catalysts for Dry Reforming of Methane (DRM) has been studied. Samples are prepared with impregnation and sol-gel methods and then calcined at 550 °C for 2 h. The catalysts were characterized by XRD, ...
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In this work, the effect of the Si/Al ratio on the activity of zeolite supported bimetallic (Ni-Co) catalysts for Dry Reforming of Methane (DRM) has been studied. Samples are prepared with impregnation and sol-gel methods and then calcined at 550 °C for 2 h. The catalysts were characterized by XRD, XRF, FESEM, BET and TGA. All samples were tested in a micro reactor at three different temperatures (i.e. 700, 750, and 800 °C). Micro reactor test results showed that 800 °C was the proper temperature for DRM. The catalyst with 5 wt % of Ni and 2.5 wt % of Co supported on γ-Alumina have shown a higher H2/CO ratio than other samples. For the zeolite supported catalysts when Ni/Co=2/1, the surface area and pore volume decreased but the H2/CO ratio increased by increasing the Si/Al ratio. Reverse the Water Gas Shift (WGS) reaction was not very active when the catalyst and support showed a basic property. Also, the stability of the catalysts has been tested for 30h on stream.