Cyrus Ghotbi | Sharif University of Technology (original) (raw)

Papers by Cyrus Ghotbi

Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, Oct 1, 2013

Journal of Petroleum Exploration and Production Technology, May 29, 2015

arXiv (Cornell University), Jul 3, 2013

Scientia Iranica, Feb 1, 2010

DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2009

Iranian Journal of Chemistry & Chemical Engineering-international English Edition, Mar 1, 2008

In this work, the PC-SAFT equation of state (EoS) has been used to model the solubility of acid g... more In this work, the PC-SAFT equation of state (EoS) has been used to model the solubility of acid gases (CO2 and H2S) in two imidazolium-based ionic liquids (ILs) ([C8-mim][PF6] and [C8-mim][Tf2N]). Parameters of pure ILs were estimated using experimental densities. Two strategies were considered to model densities of pure ILs. In strategy 1, ILs were modeled as nonassociating compounds and in strategy 2 ILs were considered as self-associating molecules and both association sites were assigned to each ILs. According to the results, the associating contribution should be taken into account in order to accurately correlate the properties of ILs. The solubility of CO2 and H2S in ionic liquids was then studied. In order to describe the experimental gas solubilities quantitatively, binary interaction parameters between the ILs and the gases were applied, which were allowed to depend linearly on temperature. After fitting a binary interaction parameter kij on experimental VLE data, the mode...

Iranian Journal of Oil and Gas Science and Technology, 2014

It has been proved that ultrasonic energy can considerably increase the amount of oil recovery in... more It has been proved that ultrasonic energy can considerably increase the amount of oil recovery in an immiscible displacement process. Although many studies have been performed on investigating the roles of ultrasonic waves, based on the best of our knowledge, little attention has been paid to evaluate wave attenuation parameter, which is an important parameter in the determination of the energy delivered to the porous medium. In this study, free fall gravity drainage process is investigated in a glass bead porous medium. Kerosene and Dorud crude oil are used as the wetting phases and air is used as the non-wetting phase. A piston-like displacement model with considering constant capillary pressure and applying Corey type approximation for relative permeabilities of both wetting and nonwetting phases is applied. A pressure term is considered to describe the presence of ultrasonic waves and the attenuation factor of ultrasonic waves is calculated by evaluating the value of external pr...

Equations of state should be tuned to reservoir conditions by PVT tests for phase behavior modeli... more Equations of state should be tuned to reservoir conditions by PVT tests for phase behavior modeling. This tuning is achievable via an optimization method. In this work, simulated annealing algorithm is applied as a global optimization method to parameter optimization for PC-SAFT from the statistical DVVRFLDWLQJ�AXLGWKHRU\�LQFRUSRUDWLQJKDUGFKDLQDVUHIHUHQFH�AXLG��7KHRSWLPL)DWLRQSDUDPHWHUV� are determined by minimizing the calculated phase behavior of a synthetic petroleum mixture and UHDOSHWUROHXP�AXLGVIURP�,UDQLDQRLODQGJDVUHVHUYRLUV��EDVHGRQWKHLU�397�WHVWV��:HH(DPLQHG� several tests, assumed to be representative of reservoir processes, such as differential liberation and constant composition expansion for oil samples and constant volume depletion for gas condensate sample. In petroleum systems, new petroleum fraction characterizing correlations were developed and validated according to PVT data and other equations of state. The results showed a high degree of accuracy for these newly...

How to cite this article: Sedghkerdar M.H., Taghikhani V., Ghotbi C., Shariati A., A modified UNI... more How to cite this article: Sedghkerdar M.H., Taghikhani V., Ghotbi C., Shariati A., A modified UNIFAC model in predicting the solubility of CO2 and H2 S in imidazolium-based ionic liquids. Journal of Oil, Gas and Petrochemical Technology, 2020; 7(1): 1-13. DOI: 10.22034/JOGPT.2020.113091. In this work, a modified UNIFAC model was proposed to investigate the solubility of acid gases, i.e., CO2 and H2S in nine imidazolium-based ionic liquids (ILs). The influence of effective parameters including temperature, the nature of anions and cations of the ILs, and the length of alkyl chain on the solubility of acid gases in the ILs were studied. The interaction parameters between the new functional subgroups of the fragmented ILs such as [IM], [BF4], [PF6], [Tf2N], CH3 and CH2 with CO2 and H2S molecules were reported using the original UNIFAC model. In the proposed model, the segment fraction in the Flory-Huggins term of the UNIFAC combinatorial part was modified considering the free-volume di...

The e ect of operation variables, such as the H2/CO molar feed ratio, gas hourly space velocity (... more The e ect of operation variables, such as the H2/CO molar feed ratio, gas hourly space velocity (GHSV), temperature, and pressure, on the catalytic performance of the Co/Mn/TiO2 catalyst prepared at the Research Institute of the Petroleum Industry (RIPI) was investigated, and optimum reactor conditions were obtained to produce the maximum amount of light ole ns. The catalyst was prepared by co-precipitation of Co and Mn phases in the presence of commercial TiO2 with maximum selectivity for ethylene and propylene production. It was found that the [H2]/[CO]=2/1, space velocity (GHSV) of 1800 h 1, 280 C temperature and 4 bar pressure were optimum operating conditions for the modi ed catalyst for the conversion of Synthesis Gas(SG) to light ole ns. The results were interpreted in terms of the structure of the catalyst. Characterizations of catalysts were carried out using XRD, SEM and BET speci c surface area.

Industrial & Engineering Chemistry Research, 2016

At harsh conditions of high pressure high temperature (HPHT), polymers undergo thermal degradatio... more At harsh conditions of high pressure high temperature (HPHT), polymers undergo thermal degradation leading to serious loss in fluid rheological and filtration properties. Nanoparticles are the most promising additives proposed to address this challenge. The stability of nanofluids is perused from various facets including rheological and filtration properties, shale stability, and zeta potential. The presence of nanoparticles could amazingly reduce the filtration at high temperatures even by 95%, and it also had a conspicuous effect on shale stability, thermal conductivity, and zeta potential. Experimental data were fit to rheological models to determine the best models describing the behavior of the nanosystem. It was clarified that the Sisko and Mizhari–Berk models enjoy the highest accuracy among the others. Moreover, a correlation is developed relating the viscosity of nanofluid to shear rate, temperature, and nanoparticles’ concentration. The model exposed high accuracy regarding a high value of avera...

Journal of Petroleum Exploration and Production Technology, 2015

This paper presents a new segment-based thermodynamic model containing the combinatorial and ener... more This paper presents a new segment-based thermodynamic model containing the combinatorial and energetic contributions to the excess Gibbs energy for correlating/predicting of the vapor-liquid equilibrium (VLE) of polymer solutions. The model is derived from the UNIQUAC-NRF model, recently proposed by Haghtalab and Asadollahi, following the idea to associate the nonideality of polymer-solvent mixture with polymer segment-solvent interaction parameters. Segment activity coefficients are calculated by means of the UNIQUAC-NRF model. At the present state of development, 16 binary segmental interaction parameters have been estimated. The capability of the model is demonstrated with successful representation of VLE correlation/prediction for 40 polymer-solvent systems. The model is capable of correlating predicting the VLE of polymer solutions with satisfactory accuracy and can provide a thermodynamic framework for calculating the VLE of polymer solutions using weakly temperature-dependent...

Toe-to-Heel Air Injection (THAI) is a novel EOR process, which integrates high temperature oxidat... more Toe-to-Heel Air Injection (THAI) is a novel EOR process, which integrates high temperature oxidation reactions and horizontal well concepts to achieve potentially high recovery rates in heavy oils. The aim of the present work is to investigate the effects of operational parameters such as injector-producer wells configuration, injectors or producers transverse distance, injector's depth of perforation and horizontal producer length on the performance of THAI in heavy oil reservoirs. Using the CMG-STARS validated combustion tube experiment model of a crushed rock and oil KEM reservoir (Fatemi and Kharrat, 2008a) and the THAI model modified with a 3D combustion cell (Fatemi and Kharrat, 2008b), a series of combustion cell assays on KEM heavy crude oil and its carbonate formation have been simulated. Different wells configurations, including vertical injector/horizontal producer (VIHP), vertical injector/2 horizontal producers (VI2HP), horizontal injector/horizontal producer (HIHP)...

Journal of the Japan Petroleum Institute, 2007