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Performance evaluation and improvement of PC-SAFT equation of state for the asphaltene precipitation modeling during mixing with various fluid types
, Article Fluid Phase Equilibria ; Volume 554 , 2022 ; 03783812 (ISSN) ; Jamshidi, S ; Sharif University of Technology
Elsevier B.V
2022
Abstract
One of the significant problems of the upstream flow assurance community is precipitation or deposition of asphaltene that leads to affect the economics of oil production seriously. Knowledge of asphaltene onset pressure (AOP) and amount of asphaltene precipitation in the change of temperature, pressure, and composition is the essential information for preventing this problem. Recent studies have shown that thermodynamic models based on the solubility nature of asphaltenes using an equation of state (EOS) are the most effective approach to asphaltene behavior modeling. In this research, the common version of the SAFT equation, known as the Perturbed Chain form of Statistical Association...
Mesoscopic rheological modeling of drilling fluids: Effects of the electrolyte
, Article Journal of Petroleum Science and Engineering ; Volume 195 , 2020 ; Ramazani Saadatabadi, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Drilling fluid is a complex fluid, including base fluid and other materials, carrying out the vital functions during drilling operation such as cutting transport and controlling formation pressure. In order to optimize performance of a drilling process, a reliable rheological model is required in the computation of fluid flow dynamics. Time-independent Generalized Newtonian formulation are the most common models for describing the rheological behavior of drilling fluids due to its simplicity and ease of use, in spite the fact that they are not able to predict the normal stresses and could not consider effects of active components on the rheological behavior of the drilling fluid and also...
Rheological modeling of water based drilling fluids containing polymer/bentonite using generalized bracket formalism
, Article Journal of Petroleum Science and Engineering ; Volume 189 , 2020 ; Ramazani Saadatabadi, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Drilling fluids consist of several components with different physical and structural form which can be assumed as complex fluids. Optimum performance of drilling process could be obtained through the dynamic fluid computation which requires a reliable mathematical model capable to predict transient and steady state rheological behavior of drilling fluid. Generalized Newtonian formulations are the most popular models for drilling fluids due to their simplicity in spite of their inabilities to predict transient and elastic behavior of such fluids. In this paper, we have developed a mathematical model to predict transient and steady state rheological behavior of the complex fluids on the scale...
Modeling of asphaltene precipitation in calculation of minimum miscibility pressure
, Article Industrial and Engineering Chemistry Research ; Volume 56, Issue 25 , 2017 , Pages 7375-7383 ; 08885885 (ISSN) ; Saeedi Dehaghani, A. H ; Sharif University of Technology
American Chemical Society
2017
Abstract
An algorithm has been developed to investigate the effect of asphaltene precipitation on calculation of minimum miscibility pressure (MMP), which is one of the key design parameters of any gas injection projects. In fact, this algorithm is the extension of procedure suggested by Jaubert et al. for prediction of MMP whatever the displacement mechanism. The vapor-liquid equilibrium calculation and then liquid-liquid equilibrium calculation are required to be taken account to estimate the amount of asphaltene precipitation. The association equation of state (AEOS) has been applied to determine the phase behavior of asphaltene. The algorithm has been used for the MMP prediction of Weyburn...
Mathematical Modeling and Experimental Investigation in Rheological Behavior of Drilling Fluids Containing Synthetic Polymers
, Ph.D. Dissertation Sharif University of Technology ; Ramazani Saadatabadi, Ahmad (Supervisor)
Abstract
Drilling fluid is one the most important part of drilling operations in the oil and gas wells digging. From an economic point of view, almost 25 to 45% of drilling costs are allocated to drilling fluid. Drilling fluids consist of several components with different physical and structural forms which can be assumed as complex fluids. Optimum performance of the drilling process could be obtained through the dynamic fluid computation which requires a reliable mathematical model capable to predict transient-state and steady-state rheological behavior of drilling fluid. Generalized Newtonian models, such as the Bingham-plastic model, the power model, and the Herschel-Bulkley model, are the most...
Mesoscopic theoretical modeling and experimental study of rheological behavior of water-based drilling fluid containing associative synthetic polymer, bentonite, and limestone
, Article Journal of Molecular Liquids ; 2021 ; 01677322 (ISSN) ; Davoodi, S ; Ramazani S.A., A ; Minaev, K.M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Employing an effective rheological model for the flow of drilling fluid that can accurately predict changing conditions is of significant importance in drilling fluid optimization. Traditional generalized Newtonian models cannot predict the time change condition, viscoelastic behavior, role of each component, or microstructural behaviors within the fluid. Consequently, the present research aims to develop constitutive equations in the framework of generalized bracket formalisms and the extra tensor concept that connect the microscopic and macroscopic properties and can overcome the aforementioned problems of traditional rheological models. The developed model is applicable for drilling fluid...
Mesoscopic theoretical modeling and experimental study of rheological behavior of water-based drilling fluid containing associative synthetic polymer, bentonite, and limestone
, Article Journal of Molecular Liquids ; Volume 347 , 2022 ; 01677322 (ISSN) ; Davoodi, S ; Ramazani S. A., A ; Minaev, K. M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Employing an effective rheological model for the flow of drilling fluid that can accurately predict changing conditions is of significant importance in drilling fluid optimization. Traditional generalized Newtonian models cannot predict the time change condition, viscoelastic behavior, role of each component, or microstructural behaviors within the fluid. Consequently, the present research aims to develop constitutive equations in the framework of generalized bracket formalisms and the extra tensor concept that connect the microscopic and macroscopic properties and can overcome the aforementioned problems of traditional rheological models. The developed model is applicable for drilling fluid...
Investigating the Influence of a Silty Layer on the Liquefaction of Saturated Sandy Soils through Numerical Methods
, M.Sc. Thesis Sharif University of Technology ; Pak, Ali (Supervisor)
Abstract
One of the main geotechnical phenomena that causes severe damage during earthquake is liquefaction. This incident occurs due to the undrained behavior of loose sandy soils. In this occurrence, the interaction between the solid and liquid phases in a cyclic motion leads to an increase in pore water pressure and a decrease in interactive forces (effective forces) between grains in the solid grains. Therefore, shear strength decreases. Different aspects of the aforementioned phenomenon is investigated, namely, field, laboratory, and numerical; nevertheless, the study is largely focused on the numerical modelling. Most studies in this field are carried out on a one-layer saturated sand. However,...
Numerical Simulation and Optimization of Sea Water Desalination by Reverse Osmosis Membrane
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Ali (Supervisor)
Abstract
Reverse osmosis (RO) is by far the most widely used membrane desalination process worldwide. The RO process depends on the properties of semi-permeable membranes which allow the separation of water from a salt solution by applying external pressure higher than the osmotic pressure on the seawater. The main problem in membrane separation process is the fouling of the membrane walls, which decreases the permeate flux. Having spacer filaments in the feed channel has been proven to dynamically change the concentration boundary layer and preventing fouling. The impact of spacer configurations (cavity, zigzag and submerged) on the alleviation of concentration polarization and the enhancement of...
Cost Efficient Task Scheduling Algorithms in Grid Environment
, M.Sc. Thesis Sharif University of Technology ; Movaghar Rahimabadi, Ali (Supervisor)
Abstract
Computational grids enabling resource sharing and coordination are now one of the common and acceptable technologies used for solving computational intensive applications rising in scientific and industrial problems. Nevertheless, due to the heterogeneity, dynamicity and autonomy of the grid resources, task scheduling within these systems has become a challenging research area. Applying the market model to the grids is a good approach which can easily take the dynamic characteristics of the grid resources into account and simplify the scheduling problem considering user-centric factors.In this thesis a two level market-based model for task scheduling problem in grid environment is presented....
Proposing an Empirical Motion-Time Pattern for Human Gaze Behavior in Different Social Situations Using Deep Neural Networks
, M.Sc. Thesis Sharif University of Technology ; Taheri, Alireza (Supervisor) ; Meghdari, Ali (Supervisor)
Abstract
A social robot is an artificial intelligence-based system designed for humans and other robots. These robots can be used in various settings. The more closely a robot resembles and behaves like a human, the more attention and popularity it will gain. The aim of this research is to humanize the behavior patterns of the robot, especially its gaze in different social situations. The social situations considered in this study are common in human life. In these situations, the robot should make decisions based on the activities that humans are engaged in. The research consists of three parts that design neural networks using LSTM and Transformers architecture. The first part utilizes data...
Feasibility Study of Economically Recovery of Residue from Terephthalic Acid Production Unit in the Tondgooyan Petrochemical Company
, M.Sc. Thesis Sharif University of Technology ; Sajadi, Ali Akbar (Supervisor) ; Matloubi Moghaddam, Firouz (Co-Advisor)
Abstract
In this work we intend toeconomically recovery of residual from terephthalic acid production unit in the Tondgooyan petrochemical company. Major component of this residual is catalysts, benzoic acid and amount of terephthalic acid product. Catalysts contains of cobalt, manganese and bromide which recycled by water extraction. Effective variable on extraction process is dilution ratio of water to residue, extraction temperature and time. Optimum condition of catalystsrecovery consist of dilution ratio of water to residue 6:1, extraction temperature and time is 45 C° and 40 minrespectively. Recovery yield of cobalt, manganese and bromide in this optimum condition is 91.21, 91.89 and 92.53...
Synthesis of Magnetic Nanocatalysis Based on Polyvinyl Derivatives and the Investigation of their Catalytic Activity in Organic Reactions
,
Ph.D. Dissertation
Sharif University of Technology
;
Matloubi Moghaddam, Firouz
(Supervisor)
;
Pourjavadi, Ali
(Supervisor)
Abstract
In recent years, the use of various catalysts has become a powerful tool in the synthesis of a wide range of biologically important molecules and or natural products toward the formation of carbon-carbon and carbon-heteroatom bonds. In the first section, the synthesis of magnetic catalyst based on acrylonitrile was reported and an attempt was made to use an efficient support and ligand to immobilize copper metals. Then, its structure was characterized by different techniques. The catalytic activity of the prepared catalyst was confirmed in the formation of indolyl diketones and the desired products were successfully synthesized with good to excellent yields. In addition, the catalyst could...
Chemical Investigation of Molasses and Reducing Sugar Wastes of Molasses in Hakim Farabi Sugar Factory
, M.Sc. Thesis Sharif University of Technology ; Alamolhoda, Ali Asghar (Supervisor) ; Matloubi Moghaddam, Firouz (Supervisor)
Abstract
Sugar extraction from cane sugar is based on crystallization. Sucrose crystallization is a mass transfer process. Sucrose molecule's migration from solution to crystal is driven by concentration difference between the mother liquor and the crystal surface; the coefficient of super saturation is the most important parameter for the process. It has large influence on product quantity and quality (crystal yield, crystal size and size distribution). In this project, first the efficiency of sucrose extraction studied by crystallization in HAKIM FARABI sugar factory. Crystal size distribution (CSD) is the more accurate measure for monitoring crystallization processes. CSD depending on the seeds...
Genome Engineering of Bacillus Subtilis Using CRISPR Technology to Overproduce Protease Production
, M.Sc. Thesis Sharif University of Technology ; Roostaazad, Reza (Supervisor) ; Banaei Moghaddam, Ali Mohammad (Supervisor)
Abstract
Enzymes are an important part of detergents, they reduce the activation energy of the reaction and thus increase the efficiency of the process. Protease enzyme is one of the most common enzymes in detergents. Bacillus strain is the most important strain in the production of this enzyme and among the species of Bacillus, Bacillus subtilis is the most used. Bacillus subtilis is a gram-positive, rod-shaped bacterium. This bacterium is considered a non-pathogenic cell that has the ability to form spores and prevent death and damage in harsh conditions. In this study, CRISPR system was used to modify the genome of Bacillus subtilis ATCC 6633 in order to increase alkaline protease. To increase the...
Increase Production of the Enzyme by Cell Genetic Modification
, M.Sc. Thesis Sharif University of Technology ; Roosta Azad, Reza (Supervisor) ; Banaei Moghaddam, Ali Mohammad (Supervisor)
Abstract
Genetic engineering of cells has been one of the most effective ways to increase protein production in wild strains. Among the various genetic engineering techniques, the CRISPR/Cas9 system that directly edits the cell chromosome, yielding greater efficiency and easier operation. In this study, we used this system to modify the genome of Bacillus subtilis ATCC 6633 to increase the production of extracellular alkaline protease enzyme. Alkaline protease enzyme has many applications in different industries, but in this study, the application of this enzyme in the detergent industry has been considered. To increase the production of this enzyme, we disrupted and prevented the gene responsible...
Design a New Magnetic Nanocatalyst Based on Palladium (II) and Its Application for the Selective Oxidation Reaction of Alcohol to Aldehyde
, M.Sc. Thesis Sharif University of Technology ; Matloubi Moghaddam, Firouz (Supervisor) ; Sajadi, Ali Akbar (Supervisor)
Abstract
In the first chapter of the thesis the synthesis of indolylsulfanyl acetamide derivatives using thio-oxindoles has been reported. The properties of this reaction are, one-pot, without using catalysts, acetonitrile solvent and the raw material is available. This reaction has high yield and seperation products is done using column chromatography. Indole derivatives has various medicinal and biological properties and synthetic products in this project has indole ring, aldehyde and amide functional groups. In the second chapter of the thesis, a new magnetic nanocatalyst has been designed. The magnetic nanoparticles were coated with triazole ligand and then palladium (II) ion was loaded onto the...
Application of Magnetic Bi-and Trimetallic Nanocatalysts Based on Fe in the Synthesis of Polycyclic Heterocycles
, M.Sc. Thesis Sharif University of Technology ; Matloubi Moghaddam, Firooz (Supervisor) ; Sajjadi, Ali Akbar (Co-Advisor)
Abstract
Nowadays, two metallic catalyst are used in many organic reaction; so,different types of these catalytic systems have been synthesized up to now and been employed. One of these systems that recently has attracted many attention is magnetic two metallic nanocatalyst, that showing very good activity due to the synergistic effect between the two metal and fine particle size.On the other hand, poly cyclic heterocyclic compounds are one the main families of organic compounds having many application in biochemicals and pharmaceuticals. The main purpose of this project is to introduce a new method for the synthesize of these compounds such as tetrazoles and 1,4-dihydropyridines, using two- and...
Monitoring of Chemical Elements and Cane Juice Impurities and the Effect on Raw Sugar Waste Agro- Industry Hakim Farbi
, M.Sc. Thesis Sharif University of Technology ; Matloubi Moghaddam, Firouz (Supervisor) ; Alamolhoda, Ali Asghar (Co-Advisor)
Abstract
Cane sugar impurities cause reduse production sugar in cane sugar industry.These impurities include polysaccharide for example starch, dextran and inorganic ash constituent such as potassium, sodium calcium magnesium and silica .The amount of impurities in the cane sugar depend on many factors including variety , grooving conditions and regional climate. Removal of impurities from cane sugar juice by clarification is an essential part of process of raw sugar manufacture. This process is based on the addition of lime, phosphates and polyelectrolyte. In this study effect of the amount of lime, phosphates and poly electrolyte on removal of various impurities has been investigated.In addition...
Stock market index prediction using artificial neural network
, Article Journal of Economics, Finance and Administrative Science ; Volume 21, Issue 41 , 2016 , Pages 89-93 ; 20771886 (ISSN) ; Hedayati Moghaddam, M ; Esfandyari, M ; Sharif University of Technology
Elsevier Doyma
2016
Abstract
In this study the ability of artificial neural network (ANN) in forecasting the daily NASDAQ stock exchange rate was investigated. Several feed forward ANNs that were trained by the back propagation algorithm have been assessed. The methodology used in this study considered the short-term historical stock prices as well as the day of week as inputs. Daily stock exchange rates of NASDAQ from January 28, 2015 to 18 June, 2015 are used to develop a robust model. First 70 days (January 28 to March 7) are selected as training dataset and the last 29 days are used for testing the model prediction ability. Networks for NASDAQ index prediction for two type of input dataset (four prior days and nine...