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Simulation and performance improvement of cryogenic distillation column, using enhanced predictive Peng–Robinson equation of state
, Article Fluid Phase Equilibria ; Volume 489 , 2019 , Pages 117-130 ; 03783812 (ISSN) ; Bayat, M ; Afshin, H ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In this study, a cryogenic distillation column has been designed and simulated via a computer code based on the theta method of convergence. The required thermodynamic properties are determined from the enhanced predictive Peng-Robinson (E-PPR 78) equation of state which has a good accuracy in predicting the corresponding thermodynamic properties of natural gas components. The combined code of distillation column/equation of state has been verified with that of another study. In the present study, the results are achieved by the constant molar over-flow and inclusion of energy equations assumptions. In order to have more accuracy in the results, the energy equations were considered in the...
An evolved cubic equation of state with a new attractive term
, Article Fluid Phase Equilibria ; Volume 408 , 2016 , Pages 58-71 ; 03783812 (ISSN) ; Jamshidi, S ; Sharif University of Technology
Elsevier
Abstract
A large variety of modifications have been presented for the temperature dependent function (α) existing in the attractive term of cubic equations of state (CEOS). Most of α-functions attempted to modify the vapor pressure prediction of polar components while other modifications have focused on both polar and non-polar compounds and other relations have considered an expansion of polynomials in the acentric factor (ω) and reduced temperature (Tr) to predict vapor pressure more accurately. In most cases such as Soave and Peng-Robinson equations of state, the suggested α-functions do not show a limiting behavior when temperature increases infinitely. In addition, the incompetency of many...
PC-SAFT modeling of petroleum reservoir fluid phase behavior using new correlations for petroleum cuts and plus fractions
, Article Fluid Phase Equilibria ; Volume 408 , 2016 , Pages 273-283 ; 03783812 (ISSN) ; Ghotbi, C ; Tavakkoli, M ; Bashiri, G ; Sharif University of Technology
Elsevier
Abstract
Parameters of the PC-SAFT Equation of State (EoS) for pure components are generally determined by matching the saturation pressure and liquid density experimental data. These experimental data are unavailable for petroleum cuts and plus fractions of the petroleum reservoir fluids. In this work, new correlations as functions of specific gravity and molecular weight were developed to estimate the PC-SAFT parameters of petroleum cuts with unknown composition. It was shown that the proposed correlations accurately estimate the PC-SAFT parameters of the pure components published in the literature. Then, the obtained correlations were used and the PVT experimental data for various real reservoir...
Measurement and correlation of CO2 solubility in the systems of CO2 + toluene, CO2 + benzene, and CO2 + n-hexane at near-critical and supercritical conditions
, Article Journal of Chemical and Engineering Data ; Volume 51, Issue 6 , 2006 , Pages 2197-2200 ; 00219568 (ISSN) ; Taghikhani, V ; Ghotbi, C ; Sharif University of Technology
2006
Abstract
The solubility of CO2 in the systems of CO2 + benzene, CO2 + n-hexane, and CO2 + toluene was meticulously measured at (293.15, 298.15, and 308.15) K and different pressures using a pressure-volume-temperature (PVT) apparatus. Also the effect of pressure on the solubility of CO2 in the organic solvents used in this work was investigated. The Peng-Robinson equation of state (PR EOS) with only one temperature-independent binary interaction parameter was used in correlating the experimental data. The results showed that the PR EOS can accurately correlate the experimental data for the solubility of CO2 in the organic solvents at high pressure. In case of the systems CO2 + benzene and CO2 +...
Modeling of Natural Gas Components Hydrate Formation by Using Neural Network
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Siroos (Supervisor) ; Taghikhani, Vahid (Supervisor)
Abstract
In this study two approaches were applied to predict the hydrate dissociation pressure of natural gas in the presence of aqueous water. One approach applied van der Waals and Platteeuw solid solution theory & PR EOS the other applied a feed forward multi layers artificial neural network (ANN) with 19 input variables (temperature, existence of hydrocarbon liquid and ice phase, gas phase composition, inhibitor composition in aqueous phase), and one hidden layer with 17 neurons. In comparison of both methods it was concluded that, in temperature above 12℃ , ANN is more accurate than thermodynamic model, but in lower temperature thermodynamic model is comparable with ANN. The trained network...
Theoretical and Experimental Study of Essential oil Extraction from Damask Rose Flower
, M.Sc. Thesis Sharif University of Technology ; Gothbi, Cyrus (Supervisor) ; Karimi Sabet, Javad (Supervisor)
Abstract
The use of medicinal plants to improve living standards has coincided with the history of human life. Throughout history, man has had no choice but to resort to plants. Among all the plants, Iranians have had a deep connection with Mohammadi flowers and throughout history have tried to extract the plant in various ways. Therefore, in this article, we have examined the method of supercritical extraction. In order to create a criterion for comparing the maximum extraction rate with the Soxhlet method and with the help of normal hexane solvent, the extraction operation was performed and its efficiency was estimated to be equal to 1.02%. Then, with supercritical experiments, it was found that...
Prediction of asphaltene precipitation during pressure depletion and CO2 injection for heavy crude
, Article Petroleum Science and Technology ; Vol. 28, issue. 9 , Mar , 2009 , p. 892-902 ; ISSN: 10916466 ; Kharrat, R ; Masihi, M ; Ghazanfari, M. , H ; Sharif University of Technology
Abstract
In this work, a thermodynamic approach is used for modeling the phase behavior of asphaltene precipitation. The precipitated asphaltene phase is represented by an improved solid model, and the oil and gas phases are modeled with an equation of state. The Peng-Robinson equation of state (PR-EOS) was used to perform flash calculations. Then, the onset point and the amount of precipitated asphaltene were predicted. A computer code based on the solid model was developed and used for predicting asphaltene precipitation data reported in the literature as well as the experimental data obtained from high-pressure, high-temperature asphaltene precipitation experiments performed on Sarvak reservoir...
Synthesis and electrochemical characterization of sol-gel-derived RuO 2/carbon nanotube composites
, Article Journal of Solid State Electrochemistry ; Vol. 18, Issue 4 , April , 2014 , pp. 993-1003 ; Online ISSN: 1433-0768 ; Asnavandi, M ; Dolati, A ; Sharif University of Technology
Abstract
Ruthenium oxide was coated on multiwalled carbon nanotubes (MWCNTs) to obtain nanocomposite electrode which has a good response to the pH. To synthesize this electrode, gold and cobalt were coated on a stainless steel 304 substrates, respectively, and then, vertically aligned carbon nanotubes were grown on the prepared substrates by chemical vapor deposition. Gold reduced activity of the stainless steel, while cobalt served as a catalyst for growth of the carbon nanotube. Ruthenium oxide was then coated on MWCNTs via sol-gel method. At last, different techniques were used to characterize the properties of synthesized electrode including scanning electron microscopy (SEM), transmission...
Phase behavior of mixture of supercritical CO2 + ionic liquid: Thermodynamic consistency test of experimental data
, Article AIChE Journal ; Volume 59, Issue 10 , 2013 , Pages 3892-3913 ; 00011541 (ISSN) ; Mohammadi, A. H ; Salamat, Y ; Shojaei, M. J ; Eskandari, S ; Richon, D ; Sharif University of Technology
2013
Abstract
Various models have been applied composed of the Peng-Robinson equation of state (PR-EoS) and the Soave-Redlich-Kwong equation of state (SRK-EoS) associated with three mixing rules including the following: Wong-Sandler (WS), van der Waals one (vdW1), and van der Waals two (vdW2) for phase behavior modeling of mixtures of supercritical CO2+different ionic liquids in vapor-liquid equilibrium (VLE) region. It has been found that the PR EoS implying the WS mixing rule can be used as a reliable thermodynamic model to perform a thermodynamic consistency test on the experimental data of phase behaviors of the supercritical CO2+ionic liquid systems (19 commonly-used ionic liquids have been studied)....
Comparative analysis of hydrate formation pressure applying cubic equations of state (eos), artificial neural network (ann) and adaptive neuro-fuzzy inference system (anfis)
, Article International Journal of Thermodynamics ; Volume 15, Issue 2 , 2012 , Pages 91-101 ; 13019724 (ISSN) ; Saber, M ; Ameri, A ; Sharif University of Technology
Abstract
The objective of this work is making comparison between thermodynamic models and data-driven techniques accuracy in prediction of hydrate formation pressure as a function of temperature and composition of gas mixtures. The Peng-Robinson (PR) and Patel-Teja (PT) equations of state are used for thermodynamic modeling and Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference System (ANFIS) are used as data-driven models. The capability of each method is evaluated by comparison with the experimental data collected from literature. It is shown that there is a good agreement between thermodynamic modeling and the experimental data in most of the cases; however, the prediction...
Supercritical gasification of biomass: Thermodynamics analysis with Gibbs free energy minimization
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 34, Issue 2 , Dec , 2011 , Pages 163-176 ; 15567036 (ISSN) ; Pazuki, G. R ; Vossoughi, M ; Saboohi, Y ; Hashemi, N ; Sharif University of Technology
2011
Abstract
Gasification of biomass in supercritical water is a successful technology for hydrogen production especially by using wet biomass. The whole process, from feeding to purification of hydrogen, consists of a lot of equipment, such as pumps, heat exchangers, heaters, reactors, etc. Because the main reactions take place in the gasification reactor, the gasifier is the most important equipment of the process. In this article, a thermodynamic model, including chemical equilibrium in the reactor that is based on Gibbs free energy minimization, is developed to estimate equilibrium composition for gasification of biomass in supercritical water for hydrogen production. For this analysis, we use three...
Prediction of asphaltene precipitation during pressure depletion and CO2 injection for heavy crude
, Article Petroleum Science and Technology ; Volume 28, Issue 9 , Apr , 2010 , Pages 892-902 ; 10916466 (ISSN) ; Kharrat, R ; Masihi, M ; Ghazanfari, M. H ; Sharif University of Technology
2010
Abstract
In this work, a thermodynamic approach is used for modeling the phase behavior of asphaltene precipitation. The precipitated asphaltene phase is represented by an improved solid model, and the oil and gas phases are modeled with an equation of state. The Peng-Robinson equation of state (PR-EOS) was used to perform flash calculations. Then, the onset point and the amount of precipitated asphaltene were predicted. A computer code based on the solid model was developed and used for predicting asphaltene precipitation data reported in the literature as well as the experimental data obtained from high-pressure, high-temperature asphaltene precipitation experiments performed on Sarvak reservoir...
Creep damage evaluation of thick-walled spheres using a long-term creep constitutive model
, Article Journal of Mechanical Science and Technology ; Volume 23, Issue 10 , 2009 , Pages 2577-2582 ; 1738494X (ISSN) ; Shokouhi, N ; Sharif University of Technology
2009
Abstract
This paper describes a numerical model developed for the computation of creep damages in a thick-walled sphere subjected to an internal pressure and a thermal gradient. The model predicts the creep damage histories during the life of the sphere, owing to variations in stresses with time and through-thickness variations. The creep damage fraction is based on the Robinson's linear life fraction damage rule, which has been incorporated in a nonlinear time-dependent stress analysis. Following the stress histories, the effective stress histories are obtained and the creep damages are calculated and summed during the life of the sphere. The material long-term creep properties up to the rupture and...
Numerical study of the mixing dynamics of trans- And supercritical coaxial jets
, Article Physics of Fluids ; Volume 32, Issue 12 , 2020 ; Farshchi, M ; Sharif University of Technology
American Institute of Physics Inc
2020
Abstract
Characterization of the transcritical coaxial injectors, accounting for the geometrical features and thermodynamics nonlinearities, is of both practical and fundamental importance. In the present study, the interactions and effects of turbulent mixing and pseudo-boiling phenomena are investigated. To do this, the mixing dynamics of bi-shear jets injected under trans- and supercritical conditions has been investigated numerically using the large-eddy simulation technique. The numerical framework provides real-gas thermodynamics and transport properties, using the Peng-Robinson equation-of-state and Chung's models, respectively. The obtained flow quantities are in good agreement with the...
An integrated approach for predicting asphaltenes precipitation and deposition along wellbores
, Article Journal of Petroleum Science and Engineering ; Volume 203 , 2021 ; 09204105 (ISSN) ; Husein, M. M ; Ghotbi, C ; Taghikhani, V ; Dabir, B ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Deposition of asphaltenes upon precipitation is a main flow assurance concern, which propelled the development of various experimental and modeling techniques to accurately predict its occurrence. This work develops an integrated approach combining thermodynamic and deposition modules with a multiphase flow simulator to simultaneously model asphaltenes precipitation and deposition in wellbores. The Peng-Robinson equation of state and the modified Miller-Flory-Huggins theory are used to calculate the thermodynamic properties of the oil and asphaltenes precipitation, respectively. The deposition module is based on conservation laws for asphaltenes transport and is linked to the flow simulator...
A new multiphase and dynamic asphaltene deposition tool (MAD-ADEPT) to predict the deposition of asphaltene particles on tubing wall
, Article Journal of Petroleum Science and Engineering ; Volume 195 , 2020 ; Jamshidi, S ; Taghikhani, V ; Sharif University of Technology
Elsevier B.V
2020
Abstract
As expounded, the precipitation and deposition of asphaltene particles in pipelines has been proved to be the most challenging flow assurance problem due to its unknown and complex behaviors. In this work, a new multicomponent, multiphase and dynamic tool was developed to model the aggregation and deposition of asphaltene particles in a bulk medium. The multiphase and dynamic asphaltene deposition tool, shortened as MAD-ADEPT is, in fact, a modified version of the previously developed ADEPT. The new tool was developed to make the asphaltene deposition and aggregation concepts in oil production wells more predictable. To tackle the complexity of the asphaltene problem, a bespoke algorithm was...