فهرست مطالب

Chemical and Petroleum Engineering - Volume:47 Issue: 1, 2013
  • Volume:47 Issue: 1, 2013
  • تاریخ انتشار: 1392/04/24
  • تعداد عناوین: 6
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  • Mona Eftekhardadkhah, Seyed Hassan Hashemabadi Page 1
    A modified model has been analytically developed to describe the induction time of an elliptic air bubble in contact with an elliptic hydrophobic oil droplet. The role of hydrophobicity was revealed in the slippage of liquid over the surfaces of bubble and droplet. In this condition, the analytical relationships for pressure distribution and consequently hydrodynamic resistance force through the water film have been reported. The obtaining results were compared with the previous models and different orientations of approaching bubble and droplet have been investigated. It was found that the induction time is very sensitive to the orientation of bubble and droplet in collision. On the other hand, the role of slippage can be shown by the decrease in pressure and hydrodynamic resistance force in liquid film and also in induction time, in comparison with the case of drainage of a film confined between two particles under no-slip boundary conditions on their surfaces.
    Keywords: Analytical solution, Induction time, Oily wastewater, Particle morphology, Slippage
  • Hamid Reza Hafizi, Atabak, Hamid Ghanbari, Tuedeshki, Anita Shafaroudi, Mahdi Akbari, Javad Safaei, Ghomi, Mojtaba Shariaty, Niassar Page 13
    Cellulose wastes of a wood and paper factory were used to produce activated carbon. Several chemical agents under various conditions were used for production of activated carbon and hence their adsorption properties have been evaluated. In addition the effect of process parameters such as raw material, chemical agent concentration, impregnation ratio, carbonization temperature, carbonization time, activation temperature, activation time, particle size and soaking time on adsorption properties and product yield have been studied. Based on experimental results, the optimum values of process parameters were determined. As an achievement, samples of activated carbon with specific surface area up to 1100 m2 /g and iodine adsorption number up to 1080 mg/g were prepared.
    Keywords: Activated carbon, Cellulose waste, Chemical activation, Adsorption
  • Gholamreza Moradi, Majid Mohadesi, Mojtaba Mokhtari Page 25
    Wax precipitate is one of the most serious issues the oil industry is currently facing, since it can cause some troubles such as increasing of the pressure losses in pipe which subsequently increases the required power for pumpage. To remove this problem, prediction of wax disappearance temperature (WDT) seems necessary. In this study, the pressure influence on the wax disappearance temperature in multi-component mixtures has been surveyed and some correlations have been proposed to predict the wax disappearance temperature instead of using thermodynamic models. The accuracies of the correlations as AARD are 0.30 %, 0.27 % and 0.68 % for binary, ternary and multi-component mixtures, respectively.
    Keywords: Wax precipitation, Thermodynamic model, Wax disappearance temperature (WDT)
  • Mohammed Rahim Ostadzehi, Rahbar Rahimi, Taleb Zarei, Mortaza Zivdar Page 37
    This research includes both experimental and CFD investigation in the hydrodynamic behavior of a new type of column tray introduced as “Concap” tray. The proposed column tray is used in contactor columns especially in stripping columns. The hydrodynamics of this Concap tray is investigated in a 1.2m in diameter column. Using air-water system, the experiments were performed for different liquid and vapor loads at constant ambient temperature and pressure. The clear liquid height and total pressure drop were measured. The results were compared with the experimental data of a valve tray in the same column simulator rig. The total pressure drop and clear liquid height of Concap tray were similar to a valve tray, having equal 14% open holes area. Liquid velocity distribution on the tray has been predicted by CFD and is reported.
    Keywords: CFD, Distillation, Concap tray, Valve tray, Hydrodynamics
  • Jaber Taheri Shakib, Hossein Jalalifar, Ebrahim Akhgarian Page 49
    Optimization of drilling fluid parameters such as mud weight, salt concentration, and temperature is essential to alleviate instability problems during drilling through shale sections. The selection of suitable mud parameters can benefit from analyses that consider significant instability processes involved in shale-drilling–fluid interactions. This paper describes the development of analytical and numerical method for describing shale deformation. Appropriate and optimum mud pressure in which the highest consistency happens is calculated with analytical and numerical methods. It was found that, the predicted mud pressures obtained from two methods are approximately equal. The stress condition is considered non-hydrostatic. From the analytical and extensive numerical simulation it was concluded that with applying any mud pressure the well shape changes from spherical to elliptical. As the selection of the optimum mud pressure is based on the less movement and maintaining the well shape constant.
    Keywords: Displacement, Mud pressure, Shale, Stress, Wellbore stability
  • Yasser Vasseghian, Mojtaba Ahmadi, Rashid Gholami, Sajad Aghaali Pages 61-70
    In this study the Dissolved Air Flotation (DAF) system in oil refinery was investigated for the treatment of refinery wastewater. In order to investigate sytem a labratory scale rig was built. The aim is to remove some of the wastewater pollutant materials and data modeling of COD test. The effect of several parameters on flotation efficiency namely, saturator pressure, and coagulant dose, on COD removal was examined experimentally. Experiments were done by using poly aluminum chloride coagulant (PAC) at pressures 2bar up to 5bar and in three doses 15mg/l، 20mg/l and 25mg/l. After final examination''s removal efficiency obtained is close to the performance achieved by the refinery. The data obtained from COD experiments using neuro-fuzzy systems have been modeled. The correlation coefficient (R2), root mean square error (RMSE) and sum of square error (SSE) of predicted values by using neuro-fuzzy systems are obtained 0. 9991, 6. 35×10-3and 4. 04×10-5 respectively, which shows the high accuracy of neuro-fuzzy systems.
    Keywords: Adaptive neuro, fuzzy inference system, COD, Dissolved air flotation, Refinery wastewater