Davood Rashtchian
Faculty of Chemical & Petroleum Engineering, Sharif University of Technology, P.O. Box 1365-8639, Tehran I.R. IRAN
[ 1 ] - Lipoxygenase-1 Leaching from Soybean Flour Employing Stirred Tank Contactor
The present work examines leaching of lipoxygenase-1 from soybean flour employing stirred tank vessel. The effect of operating parameters, impellers speed, operational period, temperature, pH and scale-up were considered.The acetic acid pH: 5.2 increased the leaching of lipoxygenase- 1.The sensitivity of agitator speed and geometrical-scale-up on the enzymeleaching has bee...
[ 2 ] - Experimental Investigation and Modeling of Asphaltene Precipitation Due to Gas Injection
Asphaltene instability is one of the major problems in gas injection projects throughout the world. Numerous models have been developed to predict asphaltene precipitation; The scaling equation is an attractive tool because of its simplicity and not involving complex properties of asphaltene. In this work, a new scaling model is presented to account for asphaltene precipitation due to gas ...
[ 3 ] - The Role of Quantitative Risk Assessment in Improving Hazardous Installations Siting: A Case Study
Safety distance has already been a main measurement for the hazard control of chemical installations interpreted to mean providing space between the hazardous installation and different types of targets. But, the problem is how to determine the enough space. This study considers the application of quantitative risk assessment to evaluating a compressed natural gas station site and to identi...
[ 4 ] - Micro-Model Experimental Study of Fracture Geometrical Effect on Breakthrough Time in Miscible Displacement Process
The miscible displacement process appears to be an increasingly feasible method for the extraction of oil from depleted reservoirs. However, there is a lack of fundamental understanding of how fracture geometrical characteristics impact the oil recovery efficiency in this type of enhanced oil recovery technique. In this work, a series of experimental tests were conducted whereby the n-Hept...
[ 5 ] - A Novel Method for Mitigation of Asphaltene Deposition in the Wellstring
Asphaltene precipitation and deposition is a serious problem in many Iranian fields. The deposited asphaltene results in partial or total blockage of the wellbore and wellstring reducing or completely seizing oil production. This paper studies the asphaltene problem and mitigation methods in wellstring systematically. It presents new approach based on the combination of thermodynam...
[ 6 ] - A New Methodology for Frequency Estimation of Second or Higher Level Domino Accidents in Chemical and Petrochemical Plants Using Monte Carlo Simulation
Some of the most destructive accidents of 1980s and 90s which occurred in process industries were domino accidents. Although domino accidents are among the most destructive industrial accidents, there are not much pioneering works done on quantification of them. The analytical formulation of the domino accidents is usually complex and need a deep knowledge of probability rules. Even if the ...
[ 7 ] - Transport Property Estimation of Non-Uniform Porous Media
In this work a glass micromodel which its grains and pores are non-uniform in size, shape and distribution is considered as porous medium. A two-dimensional random network model of micromodel with non-uniform pores has been constructed. The non-uniformity of porous model is achieved by assigning parametric distribution functions to pores throat and pores length, which was measured using ima...
[ 8 ] - Experimental Study and Modeling of Gravity Drainage during WAG Process in Fractured Carbonate Rocks
The experimental study and modeling of gravity drainage during Water Alternative Gas Injection, WAG process, in carbonate rock for one of the Iranian off-shore reservoir at lab-scale were carried out. The mechanism of gravity drainage during the WAG process, and its contribution to the oil recovery in the fract...
[ 9 ] - Experimental Study and Simulation of Different EOR Techniques in a Non-Fractured Carbonate Core from an Iranian Offshore Oil Reservoir
In this research the experimental and theoretical studies on different Enhanced Oil Recovery (EOR) techniques, i.e. Water Flooding (WF), Gas Injection (GI) and Water Alternating Gas process (WAG) were performed on specimens taken from an Iranian carbonate offshore reservoir at the reservoir condition. The experimental results for each specified techniques were compared with the correspondin...
[ 10 ] - Investigation of Auto Ignition Condition under Different Parameters
In this work, the potential of auto-ignition of heavy oil during in-situ combustion (ISC) process was studied. Kinetic studies were carried out using Thermo Gravimetric Analyzer (TGA), Differential Scanning Calorimetry (DSC) and Accelerating Rate Calorimetric (ARC) techniques. Effects of oxygen partial pressure, reservoir pressure and clay on auto ignition condition were investigated on a n...
[ 11 ] - Prediction of Hydrate Formation for the Systems Containing Single and Mixed Electrolyte Solutions
In this work the effect of electrolytes on hydrate formation was investigated. To do so, a new model was used in predicting the hydrate formation conditions in presence of both single and mixed electrolyte solutions. The new model is based on the van der Waals - Platteeuw hydrate equation of state. In order to evaluate the values for the activity of water in electrolyte solutions t...
[ 12 ] - Application of the Genetic Algorithm to Calculate the Interaction Parameters for Multiphase and Multicomponent Systems
A method based on the Genetic Algorithm (GA) was developed to study the phase behavior of multicomponent and multiphase systems. Upon application of the GA to the thermodynamic models which are commonly used to study the VLE, VLLE and LLE phase equilibria, the physically meaningful values for the Binary Interaction Parameters (BIP) of the models were obtained. Using the method proposed in t...
[ 13 ] - بررسی تجربی و مدلسازی ترمودینامیکی فرآیند استخراج لیپید از ریزجلبک مرطوب
در این مقاله، نسبتهای مختلف متانول بهعنوان حلال قطبی و هگزان بهعنوان حلال ناقطبی برای استخراج لیپید از ریزجلبک خشک و مرطوب با رطوبتهای 70 و 85 درصد استفاده شدند. مقدار لیپید استخراجی تا نسبت همحجم مخلوط هگزان و متانول روند صعودی دارد که با افزایش بیشتر متانول این روند کاهش مییابد. یک کاهش عمده لیپیدهای خام استخراجی با افزایش رطوبت در نسبتهای پایین متانول به هگزان مشاهده شد. بیشترین مق...
[ 14 ] - تعیین حریم ایمن خطوط لوله انتقال گاز ترش به روش ارزیابی کمی ریسک
یکی از مهمترین روشهای انتقال گاز، استفاده از خطوط لوله میباشد. با توجه به اینکه گاهی خطوط لوله انتقال گاز در اطراف مناطق مسکونی گسترش یافته اند و در صورت بروز نشتی یا پارگی در این خطوط، امکان ایجاد خسارتهای جانی و مالی وجود دارد، ایمنی افراد ساکن در مناطق اطراف خطوط لوله انتقال از اهمیت زیادی برخوردار است و تأمین این ایمنی از مهمترین دغدغه های صنعت ا...
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