Thermodynamics,
Volume 8, Issue 3 , July 2011, , Pages 16-30
Transport Phenomena,
Hamid Ghasemkhani; Farhad Khoshnam; Mohamad Reza Kamandar
Abstract
To improve quality attributes of the final dried product and execute a better management of the required energy, optimal process and technology it is essential to dry agri-food materials. This work is aimed at studying the dehydration characteristics and qualitative traits (color, shrinkage, rehydration ...
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To improve quality attributes of the final dried product and execute a better management of the required energy, optimal process and technology it is essential to dry agri-food materials. This work is aimed at studying the dehydration characteristics and qualitative traits (color, shrinkage, rehydration ratio) of apple in a rotating-tray convective dryer with different operational variables. Furthermore, to model the dehydration curves, the usage of some well-known semi-theoretical models and artificial neural networks (ANNs) was evaluated. The drying experiments were conducted by applying the constant thickness of the samples (3 mm), different air temperatures (50‒85 °C) and flow rates (1 and 2 m s-1) as well as three tray rotating speeds (0, 6 and 12 rpm). In addition to significant (P < 0.05) reduction caused by increasing the temperature and flow rate, the process duration was considerably decreased by the increment in the tray rotating speed. The moisture diffusion inside the slices (2.708 × 10-9 ‒ 8.337 × 10-9 m2 s-1) was facilitated by increasing the values of evaluated variables. The average values for the activation energy changed from 20.47 to 23.80 kJ mol-1. In comparison with the thin layer models, artificial networks showed better performance in modeling the curves. Although drying parameters did not significantly affect the quality of studied properties, in general, higher drying air velocities and temperatures deteriorated the quality of the final products
Modeling and Simulation
Volume 11, Issue 2 , April 2014, , Pages 17-28
Separation Technology,
Volume 7, Issue 3 , July 2010, , Pages 17-28
Transport Phenomena,
Volume 7, Issue 2 , April 2010, , Pages 17-27
Modeling and Simulation
Volume 3, Issue 3 , July 2006, , Pages 17-28
Abstract
In this paper a two impinging streams cyclone contacting system suitable for handling of solid-liquid systems has been studied. Certain pertinent parameters such as: solid holdup, mean residence time and Residence Time Distribution (RTD) of solid particles have been investigated. A stochastic model based ...
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In this paper a two impinging streams cyclone contacting system suitable for handling of solid-liquid systems has been studied. Certain pertinent parameters such as: solid holdup, mean residence time and Residence Time Distribution (RTD) of solid particles have been investigated. A stochastic model based on Markov chains processes has been applied which describe the behavior of solid particles in the contacting system. From this model the RTD data were estimated and compared with the experimental results. The RTD data were obtained at different Dt and compared with those estimated from the model. At Dt = 0.362 s a good correlation has been observed between the predicted and experimental data. The RTD data may be used to determine certain pertinent characteristic parameters of physical and chemical apparatuses such as conversion in chemical reactors.
Thermodynamics,
Volume 3, Issue 4 , October 2006, , Pages 17-22
Abstract
In this work the volume expansion for the binary systems of ethanol and toluene, as industrial organic solvents, in the presence of nearcritical and supercritical carbon dioxide, CO2, at a temperature range of 293 to 333 K has been meticulously measured. The effect of the temperature and pressure of ...
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In this work the volume expansion for the binary systems of ethanol and toluene, as industrial organic solvents, in the presence of nearcritical and supercritical carbon dioxide, CO2, at a temperature range of 293 to 333 K has been meticulously measured. The effect of the temperature and pressure of binary systems on volume expansion for organic solvents have also been investigated. It can be observed that by increasing the pressure of the system at a constant temperature, the volume of the liquid phase increases smoothly, while at higher pressures a sudden volume expansion can occur. The range of pressure that can lead to a sudden increase in the volume expansion of the liquid phase in each specified temperature can be reported as a proper condition in producing micro and nanoparticles. The experimental data for the volume expansion of organic solvents were modeled using the conventional cubic Peng Robinson equation of state. The Average Absolute Relative Deviation percent (AARD%) for the binary systems of ethanol + CO2 and toluene + CO2 were reported as 14.9% and 15.1%. As inferred, it is vital to develop a thermodynamic model with greater accuracy in order to correlate the volume expansion of the systems studied in this work at various conditions.
Separation Technology,
Mo. H. Almasvandi; M. Rahimi
Volume 14, Issue 4 , December 2017, , Pages 17-31
Abstract
This paper reports the results of experimentally removing ammonia from synthetically prepared ammonia solution using a micro scale mixing loop air stripper. Effects of various operational parameters (such as: pH, air flow rate, wastewater flow rate and initial ammonia concentration) were evaluated. By ...
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This paper reports the results of experimentally removing ammonia from synthetically prepared ammonia solution using a micro scale mixing loop air stripper. Effects of various operational parameters (such as: pH, air flow rate, wastewater flow rate and initial ammonia concentration) were evaluated. By increasing the pH from 10 to 12.25 the amount of KLa increased from 0.26 to 0.73 hr-1. A considerable enhancement, about 150%, can be found for KLa by changing the air flow rate from 280 to 700 mL/min under fixed condition. The wastewater flow rate can also the value of KLa from 0.22 to 0.59 hr-1. The values of KLa increased only about 20% by changing the initial concentration of ammonia in the range between 50 and 500 mg/L. The results showed that improving in air stripping using microchannel was successfully carried out with enhancing overall volumetric mass transfer coefficient (KLa) and providing higher mass transfer capabilities compared with other types of strippers, even for lower amounts of used air. The enhancement of mass transfer is happened by efficient mixing induced by the employed microchannel. It has been demonstrated that wastewater flow rate and air flow rate have significant effects on KLa. The optimal stripping conditions and mathematical modeling for ammonia removal and the relation between the parameters were determined using Response Surface Methodology (RSM) with Central Composite Design (CCD) method. The results demonstrate the advantages the proposed system over convention stripper types.
Modeling and Simulation
I. Omidi; M. Kalbasi
Volume 14, Issue 2 , 2017, , Pages 17-32
Abstract
The performance of the solid acid fuel cell by CsH2PO4 electrolyte was analyzed using the present model of the electrochemical reaction and transport phenomena, which are fully coupled with the governing equations. Development of such a model requires creating the three-dimensional geometry and its mesh ...
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The performance of the solid acid fuel cell by CsH2PO4 electrolyte was analyzed using the present model of the electrochemical reaction and transport phenomena, which are fully coupled with the governing equations. Development of such a model requires creating the three-dimensional geometry and its mesh grid, discretization of momentum, mass and electric charge balance equation and solving the equations based on the information of electrical and electrochemical models in different areas of the cell consisting of porous electrodes, gas channels, and the solid parts like the current collector. The model equations were solved employing a finite elements technique solver of cell potential. Different parameters including current density (i), cell potential (V), cell power and concentration distribution of hydrogen, oxygen and water vapor have been investigated in this study. Also, the effect of different voltages on the concentration distribution of all the mentioned species through the cell length are taken into account. Comparing the polarization curve values with the experimental results shows a good agreement between the computed and experimental values (Maximum error is less than 4%). The results showed that there is a noticeable difference between H2, O2 and H2O concentration through the cell length subjected to various voltages. This difference was more apparent at lower voltages due to higher current density and higher consumption of species. The polarization curve is well consistent with the model and experimental data which verify the present simulation results.
Separation Technology,
M. Shafiee; A. Akbari; B. Ghiassimehr
Volume 15, Issue 4 , November 2018, , Pages 17-26
Abstract
At this work, removal of Pb (II) using Lawsonia inermis (Henna) was studied. In recent years, use of low price adsorbent is taken into consideration. Adsorption experiments were performed in batch system at ambient temperature (25℃). The influence of some parameters such as time, initial metal concentration, ...
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At this work, removal of Pb (II) using Lawsonia inermis (Henna) was studied. In recent years, use of low price adsorbent is taken into consideration. Adsorption experiments were performed in batch system at ambient temperature (25℃). The influence of some parameters such as time, initial metal concentration, pH and adsorbent dose were investigated. The optimum conditions was obtained at pH of 6, 10 ppm of initial metal concentration, 80 min of contact time and 0.75 g/L of adsorbent dose. To study the adsorbent morphology, Scanning Electron Microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) was used before and after adsorption of Pb (II) ions. Sorption of Pb (II) was evaluated by Freundlich and Langmuir isotherms. The results indicate that the Freundlich isotherm model is better described the adsorption of Pb (II) than Langmuir isotherm model. Also, it is observed that, the pseudo-second-order kinetic model well fitted to experimental data .
Process Control and Engineering, Process Safety, HSE
Volume 8, Issue 2 , April 2011, , Pages 18-28
Biomedical and Biotechnology,
A. Zabihollahpoor; P. Hejazi
Volume 15, Issue 1 , February 2018, , Pages 18-34
Abstract
In this study, the effects of some factors on bacterial growth and ferrous oxidation rates were investigated by Acidithiobacillus ferrooxidan in 250 ml shake flasks. One factor at a time (OFAT) design approach was used for preliminary evaluation of various factors affecting the process, such as pH, initial ...
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In this study, the effects of some factors on bacterial growth and ferrous oxidation rates were investigated by Acidithiobacillus ferrooxidan in 250 ml shake flasks. One factor at a time (OFAT) design approach was used for preliminary evaluation of various factors affecting the process, such as pH, initial ferrous and elemental sulfur concentrations, shaker agitation rate, and liquid to flask volume ratio. After that, optimal levels of effective last three factors to achieve high oxidation rate and cell growth rate were investigated using a full factorial design. It was obtained that agitation rate and liquid to flask volume, as well as their binary interaction, are significant factors on ferrous iron bio-oxidation rate. In contrast, initial high ferrous iron concentration was the only effective factor on the cell growth rate. Maximum bio-oxidation rate of 0.417 g/L was achieved at the media with Fe2+ ion concentration of 30 g/l, agitation rate of 200 rpm, and liquid to flask volume ratio of 20% by full factorial optimization, which is an about 40% increase compared to the result obtained in OFAT method. Then, the effect of step-wise adaptation of A. ferrooxidans to in high Fe2+ concentration was studied, and about 40% reduction in bacterial lag phase time, and 36 and 86% increase in bacterial growth rate and bio-oxidation rate were acquired, respectively.
Modeling and Simulation
Volume 11, Issue 1 , January 2014, , Pages 19-29
Separation Technology,
Jafarsadegh Moghaddas; Leila Amirkhani; Hoda Jafarizadeh- Malmiri
Volume 13, Issue 3 , July 2016, , Pages 19-31
Abstract
Magnetic silica aerogel in hydrophobic and hydrophilic forms were used as support to immobilize Candida rugosa lipase by adsorption method. Response surface methodology (RSM) was employed to study the effects of the three most important immobilization parameters, namely enzyme/support ratio (0.3-0.5, ...
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Magnetic silica aerogel in hydrophobic and hydrophilic forms were used as support to immobilize Candida rugosa lipase by adsorption method. Response surface methodology (RSM) was employed to study the effects of the three most important immobilization parameters, namely enzyme/support ratio (0.3-0.5, w/w), immobilization time (60-120 min) and alcohol percentage (20-40, %v/v) on the specific activity of immobilized lipase on the hydrophobic supports. For hydrophilic supports, alcohol percentage was removed as there was no need for pre-wetting step in enzyme immobilization process. Second order regression models with high coefficient determination (R2) values of higher than 0.98 were fitted to predict the response as function of immobilization parameters. The results indicated that for hydrophobic supports, optimum values for enzyme/support ratio, immobilization time and alcohol percentage were obtained at 0.45 (w/w), 94.27 min and 38.81 %, respectively, in which specific activity were predicted at 15.32 U/mg-protein. For hydrophilic supports, the optimum enzyme/support ratio and immobilization time were predicted at 0.47 (w/w) and 83.47 min, respectively. Specific activity in these conditions were obtained 11.21 U/mg-protein. As the difference between the experimental and predicted values was showed as non-significant, the response surface models employed could be considered as adequate.
Separation Technology,
P. Azadi; Sh. Hassanajili
Volume 14, Issue 3 , August 2017, , Pages 19-30
Abstract
In recent years, plasma treatments have given good results since they offer high technological efficiency with low waste generation. One of the most important characteristics of plasma methods is their action only on a thin surface layer, whereas the bulk of sample remains unchanged and the modified ...
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In recent years, plasma treatments have given good results since they offer high technological efficiency with low waste generation. One of the most important characteristics of plasma methods is their action only on a thin surface layer, whereas the bulk of sample remains unchanged and the modified material keeps its chemical and mechanical properties. In this research, polyurethane membrane surface was modified by low frequency plasma grafting with methacrylic acid and acrylamide monomers to alter solution-diffusion mechanism. We chose different parameters of plasma treatment and studied their effects toward maximum solubility, permeation and selectivity. The grafting on the surfaces was characterized by water contact angle measurement and atomic force microscopy. After confirming a successful grafting, we studied the effect of surface modification on permeation of CH4 and CO2. Significant increase in CO2 permeation and about 32 percent increase in CO2/CH4 selectivity was observed. Better results were obtained for low powers and acrylamide grafted surface.
Reaction Engineering, Kinetics and Catalysts,
M. Takht Ravanchi; S. Sahebdelfar; M. Rahimi Fard; H. Moosavi
Abstract
The impregnation of the alumina support with the PdCl2 solution was investigated in batch and semi-batch operation modes using a recycle packed-bed reactor. The UV-visible analysis was used to evaluate the kinetics of the adsorption of Pd on the alumina support. The adsorption data related to transient ...
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The impregnation of the alumina support with the PdCl2 solution was investigated in batch and semi-batch operation modes using a recycle packed-bed reactor. The UV-visible analysis was used to evaluate the kinetics of the adsorption of Pd on the alumina support. The adsorption data related to transient palladium showed that the adsorption of Pd was very rapid and completed within few minutes. Bi-metallic Pd-Ag/Al2O3 catalysts were synthesized by the sequential impregnation method. CO-chemisorption, CO-TPD and FE-SEM tests were used to characterize the synthesized bi-metallic samples. The catalytic performance of the samples was evaluated for the tail-end acetylene selective hydrogenation process in a fixed-bed reactor. Moreover, the deactivation of the catalysts was evaluated mathematically by the integral method of analysis, considering reaction kinetics as power laws in terms of nth orders in H2 and C2H2 partial pressures. It was observed that by the batch-wise addition of the Pd precursor solution, a sample, with the lowest amount of Pd dimmers that had the highest ethylene selectivity and lowest hydrogenation reaction rate, was obtained.
Polymer Engineering and Technology,
F. derakhshanfard; A. vaziri; N. Fazeli; A. Heydarinasab
Volume 13, Issue 1 , January 2016, , Pages 20-31
Abstract
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 ...
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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.
Separation Technology,
R. Bakhshi; M. Moraveji; A. Parvareh
Abstract
The polysulfone mixed matrix membranes (MMM) with different concentrations of graphene oxide (0, 0.25, 0.5 wt % of the polymer) are fabricated by a phase separation method. The cross-sectional structures and their upper surface were assessed by the (SEM) surface roughness of the membranes assessed by ...
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The polysulfone mixed matrix membranes (MMM) with different concentrations of graphene oxide (0, 0.25, 0.5 wt % of the polymer) are fabricated by a phase separation method. The cross-sectional structures and their upper surface were assessed by the (SEM) surface roughness of the membranes assessed by (AFM). The mechanical and thermal stability of the fabricated membranes were evaluated as well. The separation of Carbon dioxide, nitrogen and methane from natural gas was considered. Also, by increasing the concentration of graphene oxide in the polymer matrix, the thickness of the spongy structure increases and the holes of the finger-like membranes are also destroyed. From the cross-sectional images of the outer surface of the MMM, it was concluded that an active selector layer was created on the lower surface of the membrane. The membrane tensile strength and the length of the membrane at fracture point increased slightly with an increase in the concentration of graphene oxide. Transition Glass temperature of the membrane increased by the addition of graphene oxide to the structure. From TGA analysis, in the presence of graphene oxide, the thermal stability improved. From the gas permeation test, by the addition of 0.25 % of graphene oxide to the polymer, CO2 permeability was increased from 61.22 GPU to 76.04 GPU, while the addition of 0.5 wt % resulted in a lower permeability (69.55 GPU). The Nitrogen gas permeation flux of membranes decreased from 10.93 GPU to 3.91 GPU by the addition of 0.50 wt % of graphene oxide. The Methane gas permeation flux is reduced from 11.31 GPU to 6.95 GPU and 4.92 GPU by the addition of 0.25 % and 0.50 % of graphene oxide respectively. In conclusion, an increase in the concentration of graphene oxide increased the carbon dioxide selectivity.
Reaction Engineering, Kinetics and Catalysts,
M. Basiri; M. Rahimi; H. Babaei Mohammadi
Volume 13, Issue 2 , April 2016, , Pages 22-32
Abstract
The ultrasound-assisted (UA) soybean oil methanolysis using KOH as a catalyst was studied at different reaction conditions in a microreactor. Box–Behnken experimental design, with three variables, was performed and the effects of three reaction variables i.e. reaction temperature, catalyst concentration ...
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The ultrasound-assisted (UA) soybean oil methanolysis using KOH as a catalyst was studied at different reaction conditions in a microreactor. Box–Behnken experimental design, with three variables, was performed and the effects of three reaction variables i.e. reaction temperature, catalyst concentration and the methanol-to-oil molar ratio on fatty acid methyl ester (FAME) yield were evaluated by method of analysis of variance (ANOVA) and multiple regression. A quadratic polynomial model was obtained to predict the methyl ester yield. A yield of 97.1% for methyl ester was obtained at the deduced optimal conditions: reaction temperature of 47 °C, KOH catalyst concentration of 1.29% (w/w) and methanol-to-oil molar ratio of 6:1. Validation experiments confirmed the validity of the predicted model. At the optimal operation condition for the ultrasonic process, a higher yield of methyl esters was obtained in comparison with that of the non-ultrasonic layout. The results show that UA transesterification in microreactor minimizes the reaction time and temperature, alcohol-to-oil molar ratio as well as energy consumption.
Modeling and Simulation
N. Hadi; A. Niaei; r. alizadeh
Volume 15, Issue 2 , May 2018, , Pages 22-37
Abstract
The high silica Mn-substituted MFI metallosilicate catalyst with Si/Al molar ratio of 220 and Si/Mn molar ratio of 50 was successfully synthesized by hydrothermal method. The catalyst sample was appropriately characterized by XRD, FE-SEM, EDX and BET techniques. The Mn-substituted MFI metallosilicate ...
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The high silica Mn-substituted MFI metallosilicate catalyst with Si/Al molar ratio of 220 and Si/Mn molar ratio of 50 was successfully synthesized by hydrothermal method. The catalyst sample was appropriately characterized by XRD, FE-SEM, EDX and BET techniques. The Mn-substituted MFI metallosilicate has not been reported as the potential catalyst for the methanol to propylene (MTP) reaction. The prepared catalyst was examined in the MTP reaction at the optimal operating conditions. Furthermore, for elucidating the flow field of the MTP fixed bed reactor, a three-dimensional (3D) reactor model was developed. A detailed reaction mechanism which was proposed for the MTP reaction over the Mn-impregnated MFI zeolite (Mn/H-ZSM-5) was properly employed. The reaction mechanism was integrated to a computational fluid dynamics (CFD) for simulating the kinetic, the energy equation and the hydrodynamics of the MTP process, simultaneously. The component distribution during proceeding of the MTP reaction was also simulated as a function of time on stream. The CFD modeling results were validated by the actual data which were obtained over the Mn-substituted MFI metallosilicate catalyst. With regard to the findings, the experimental data were in good agreement with the predicted values of the CFD modeling.
Petroleum and Reservoir Engineering
Volume 5, Issue 2 , April 2008, , Pages 23-33
Abstract
Precipitation ofsolid paraffins is one ofthe most common problems in the oil industry, imposing high operating costs. There have been a great many efforts for the prediction of solid paraffins precipitation up to now. Most of them were based on activity coefficient models accounting to solid phase non-ideality ...
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Precipitation ofsolid paraffins is one ofthe most common problems in the oil industry, imposing high operating costs. There have been a great many efforts for the prediction of solid paraffins precipitation up to now. Most of them were based on activity coefficient models accounting to solid phase non-ideality or the multi-solid model to calculate the number ofprecipitated solid phases. In this work, solid phase behavior is predicted by a solid equation of state. At first, by using the thermodynamic method (subcoled liquid) for pure solid phase fugacity from pure liquid fugacity, the solid EOS parameters are tuned. The tuned solid EOS can then be directly applied for the prediction of the amount of precipitated solid paraffins (waxes) in the oil samples. The proposed equations system in this work is solved by a proper mathematical method. The obtained results of wax precipitation in this work are in good agreement with the experimental data.
M.E zeynali; H. Abedini; H. R. Sadri
Volume 16, Issue 3 , September 2019, , Pages 23-36
Abstract
Divinylbenzene (DVB) is produced by catalytic dehydrogenation of DEB at high temperature and atmospheric pressure. Ethylvinylbenzene (EVB) is produced as a useful chemical during dehydrogenation of DEB. Also some other liquid and gaseous by products is produced during dehydrogenation. A set-up has been ...
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Divinylbenzene (DVB) is produced by catalytic dehydrogenation of DEB at high temperature and atmospheric pressure. Ethylvinylbenzene (EVB) is produced as a useful chemical during dehydrogenation of DEB. Also some other liquid and gaseous by products is produced during dehydrogenation. A set-up has been developed to conduct the DEB dehydrogenation reactions experiments to prepare DVB at different conditions. Model equations for DEB dehydrogenation reactor have been solved by genetic algorithm (GA) method using MATLAB software. Reaction rate constants and absorption coefficients were determined at various temperatures. The conversion of DEB and ethylvinyl benzene (EVB) in the reactor was predicted by mathematical modeling and compared with experimental results. The comparison shows good agreements between experimental and modeling results. The combined effects of DEB flow rate and catalyst weight as time factor were investigated on conversion of DEB and production of EVB and DVB. Effects of temperature on consumption of DEB and production of EVB and DVB in the tubular reactor were investigated.
Petroleum and Reservoir Engineering
A. Arinkoola; T. Salawudeen; K. Salam; M. Jimoh; Z. Atitebi; G. Abidemi
Volume 16, Issue 1 , March 2019, , Pages 39-53
Abstract
Research has shown that many Bentonite in Nigeria are unsuitable for oil well drilling in their natural states. Their modification and blends with some additives could increase the yield and boost their suitability. Many indigenous polymers have become very popular due to environmental friendliness and ...
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Research has shown that many Bentonite in Nigeria are unsuitable for oil well drilling in their natural states. Their modification and blends with some additives could increase the yield and boost their suitability. Many indigenous polymers have become very popular due to environmental friendliness and their ability to modify rheology of clay suspension. However, the common natural polymers are characterized with excessive fluid loss, low gel strength at typical reservoir conditions. The aim of this study is therefore to examine the influence of selected polymers on the physicochemical and rheological properties of Nigerian clay-water suspension. Mud samples were prepared with polymers according to mud formulations currently used in the wells drilling with properties varied and optimized in a Reduced Central Composite Design (RCCD). The physico-chemical (pH, mud weight), rheological (plastic viscosity, yield point) and fluid loss were measured out on the studied muds. The results show that, the rheological characteristics of studied muds (PV (19.4 ± 1.50 cp) and Yp (21.5 ± 0.79 lbf/100ft2), the Fluid loss (10.12 ± 0.45 ml/30 minutes/100 psi) and 10 min and sec Gel value (4.6 ± 0.05 and 5.1 ± 0.01 lb/100ft2) were clearly improved. However, the mud weight values recorded (8.6 – 8.9 lb) though satisfied the minimum 8.6 lb/gal ceiling value but was due to the local barite that this study evaluated. The barite is characterized with low specific gravity and we recommend its modification prior to use to avoid high sand content.
Transport Phenomena,
Volume 1, Issue 2 , July 2004, , Pages 19-27
Abstract
The present study attempted deriving and solving the falling- cylinder governing equations for power law model non-Newtonian fluids. Based on this theoretical study, a novel falling- cylinder rheometer (FCR) was designed and constructed to measure the Theological properties of non-Newtonian fluids. Different ...
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The present study attempted deriving and solving the falling- cylinder governing equations for power law model non-Newtonian fluids. Based on this theoretical study, a novel falling- cylinder rheometer (FCR) was designed and constructed to measure the Theological properties of non-Newtonian fluids. Different falling cylinders with predesigned densities were used to determine the apparent viscosity of polyvinyl alcohol (PVA) solutions in water with various concentrations. The results indicate that all PVA solutions obey the power law model with the power law index as well as the consistency index changing linearly with concentration. Increasing concentration of the solution decreases power law index, while enhances consistency index and apparent viscosity.
Separation Technology,
Volume 8, Issue 1 , January 2011, , Pages 20-30