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paraffins
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Thermal and catalytic hydrocracking of Iranian Paraffin: A unique lumped kinetic model
, Article Scientia Iranica ; Volume 6, Issue 5 , 2000 , Pages 92-97 ; 10263098 (ISSN) ; Akbarnejad, M. M ; Badakhshan, A ; Khorasheh, F ; Sharif University of Technology
Sharif University of Technology
2000
Abstract
In this paper, thermal and catalytic hydrocracking of liquid paraffin hydrocarbons, from Tehran refinery, is studied using a pilot plant reactor. The experimental system consisted of a vertical tubular flow reactor where hydrogen and liquid products were fed from the top of the reactor and after passing through a bed of catalyst (or quartz beads in the case of thermal hydrocracking experiments), the liquid and gaseous products were separated and sampled for subsequent analyses. The reaction temperature was in the range of 410-430°C for catalytic hydrocracking and 440-470°C for thermal hydrocracking experiments. The space velocities for both sets of experiments varied between 0.5 to 1.5...
Synthesizing soot particles in a paraffin-oil flame
, Article 6th International Conference on Fluid Flow, Heat and Mass Transfer, FFHMT 2019, 18 June 2019 through 19 June 2019 ; 2019 ; 23693029 (ISSN); 9781927877593 (ISBN) ; Ghafourizadeh, M ; Schneider, G. E ; Sharif University of Technology
Avestia Publishing
2019
Abstract
In this paper, we would like to know how to synthesize soot in a paraffin-oil flame. To do this, we use an in-house developed numerical code and simulate the soot formation in a turbulent paraffin-oil flame. However, it is necessary to evaluate first this code to ensure its reliable prediction of the soot formation and thermal behavior of the flame. So, we simulate a benchmark turbulent paraffin-oil flame and compare our obtained results against the available experimental data. The comparison insinuates the capability of current numerical code in correct predictions of both flame structure and pollution species. Then, a glass slide is installed inside the combustor. This disk-shaped glass...
Synthesizing soot particles in a paraffin-oil flame
, Article 6th International Conference on Fluid Flow, Heat and Mass Transfer, FFHMT 2019, 18 June 2019 through 19 June 2019 ; 2019 ; 23693029 (ISSN); 9781927877593 (ISBN) ; Ghafourizadeh, M ; Schneider, G. E ; Sharif University of Technology
Avestia Publishing
2019
Abstract
In this paper, we would like to know how to synthesize soot in a paraffin-oil flame. To do this, we use an in-house developed numerical code and simulate the soot formation in a turbulent paraffin-oil flame. However, it is necessary to evaluate first this code to ensure its reliable prediction of the soot formation and thermal behavior of the flame. So, we simulate a benchmark turbulent paraffin-oil flame and compare our obtained results against the available experimental data. The comparison insinuates the capability of current numerical code in correct predictions of both flame structure and pollution species. Then, a glass slide is installed inside the combustor. This disk-shaped glass...
The impingement of liquid boiling droplet onto a molten phase change material as a direct-contact solidification method
, Article Thermal Science and Engineering Progress ; Volume 23 , 2021 ; 24519049 (ISSN) ; Mohammadi, O ; Hosseininaveh, H ; Shafii, M. B ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The boiling of a fluid dripping on the surface of molten phase-change materials provides an efficient means for heat exchange or cooling of the melt. For the first time, in this study, the impact of acetone drops onto molten paraffin as a direct-contact solidification method is experimentally investigated to get a better insight into the interaction between the drop boiling and the heat extraction process from the phase change materials during impact. As the acetone drop impacts the molten paraffin surface, acetone starts to boil, and a portion of molten paraffin is solidified. Four impact Weber numbers (corresponding to heights of 10, 20, 30, and 40 cm) for the acetone drop and six surface...
Kinetic parameters optimization and modeling of catalytic dehydrogenation of heavy paraffins to Olefins
, Article Petroleum Science and Technology ; Vol. 32, issue. 7 , April , 2014 , pp. 813-820 ; ISSN: 10916466 ; Khorasheh, F ; Nakhjavani, M. H ; Fattahi, M ; Sharif University of Technology
Abstract
A mathematical model for a fixed bed radial flow catalytic reactor was developed for dehydrogenation of heavy paraffins over Pt-Sn/Al2O3 catalyst. The model included appropriate kinetic rate expressions for the main dehydrogenation reaction as well as side reactions and catalyst deactivation. The reactor model consisted of a set of partial and ordinary as well as algebraic equations that were solved numerically to determine the concentration of various species along the radius of the bed as a function of time. The Nelder-Mead optimization method was used to obtain the optimum kinetic parameters. The validity of the model was demonstrated by comparing the predicted paraffin conversion and...
Separation of Olefins from Paraffins Using Nanocomposite Polymeric Membranes
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor) ; Goodarznia, Iraj (Supervisor)
Abstract
In this study, fabrication of polymeric nanocomposite membranes for separation of olefins from paraffins was investigated. Silver nanoparticles were prepared by Polyol chemical reduction method. At first, dense ethylcellulose and ethylcellulose-silver nanoparticles membranes were fabricated by solvent-evaporation method. Then Asymmetric EC and EC-silver nanoparticle nanocomposite membranes were fabricated by dry/wet phase inversion method as a means to improve flux rates and olefin selectivity in olefin/paraffin separations. The membranes properties and The Effects of incorporating nanoparticles in polymer matrix in low concentration on gas permeability and membranes morphology were...
Immiscible Displacement of a Wetting Fluid by a Non-wetting One at High Capillary Number in a Micro-model Containing a Single Fracture
, Article Transport in Porous Media ; Volume 94, Issue 1 , 2012 , Pages 289-301 ; 01693913 (ISSN) ; Rashtchian, D ; Shadizadeh, S. R ; Sharif University of Technology
Abstract
Most reservoirs in Iran are heterogeneous fractured carbonate reservoirs. Heterogeneity causes an earlier breakthrough and an unstable front which leads to a lower recovery. A series of experiments were conducted whereby the distilled water displaced n-Decane in strongly oil-wet glass micro-models containing a single fracture. Experimental data from image analysis of immiscible displacement processes are used to modify the Buckley-Leverett and fractional flow equations by a heterogeneity factor. It is shown that the heterogeneity factor in the modified equations can be expressed as a function of fracture length and orientation
A modified free-volume-based model for predicting vapor-liquid and solid-liquid equilibria for size asymmetric systems
, Article Fluid Phase Equilibria ; Volume 234, Issue 1-2 , 2005 , Pages 94-100 ; 03783812 (ISSN) ; Ghotbi, C ; Taghikhani, V ; Kontogeorgis, G. M ; Sharif University of Technology
2005
Abstract
The main purpose of this work is to present a free-volume combinatorial term in predicting vapor-liquid equilibrium (VLE) and solid-liquid equilibrium (SLE) of polymer/solvent and light and heavy hydrocarbon/hydrocarbon mixtures. The proposed term is based on a modification of the original Freed Flory-Huggins model, replacing the molar volume with a free-volume (FV) term. Using an extensive database for athermal polymer solutions at finite dilution, the single parameter of the model has been well adjusted. The results obtained from the model proposed in this work were favorably compared with those obtained from the well-established entropic-FV based models, i.e., the original entropic-FV...
Investigation of the Effect of Asphaltene on Interfacial Tension Behavior of CO2/Oil Systems during CO2 Injection into Asphaltenic Oil Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Taghikhani, Vahid (Supervisor) ; Ayatollahi, Shahabeddin (Supervisor)
Abstract
Interfacial Tension (IFT) behavior of crude oil/CO2 system is recognized as the main factor affecting the efficiency of CO2 flooding during enhanced oil recovery (EOR) process. Adding paraffin group hydrocarbon to asphaltenic crude oils as an asphaltene precipitant component is aimed to mimic asphaltene precipitation process during crude oil production and transportation. Asphaltene precipitation would critically effects the IFT behavior of crude oil/CO2 systems. In the first part of this study, the equilibrium densities of oil samples which contain different heptane ratio were measured at different pressures and the temperature of 323 K. Then, the equilibrium IFT between CO2 and the crude...
Temperature and composition effect on CO2 miscibility by interfacial tension measurement
, Article Journal of Chemical and Engineering Data ; Volume 58, Issue 5 , March , 2013 , Pages 1168-1175 ; 00219568 (ISSN) ; Escrochi, M ; Ayatollahi, S ; Sharif University of Technology
2013
Abstract
Crude oil reservoirs have different temperatures, compositions, and pressures, therefore oil recovery performance by CO2 injection varies from one case to another. Furthermore, it is predicted that lower interfacial tension between injected CO2 and reservoir fluid results in more oil recovery. In this study, we investigate the effect of temperature on the equilibrium interfacial tension between CO2 and three different oil fluids at different pressures. Also minimum miscible pressure (MMP) is measured by the vanishing interfacial tension (VIT) technique to determine the temperature effect on the CO2 miscible gas injection. The results on different pure and mixtures of hydrocarbon fluids show...
Investigating the effect of several auxiliary carbon sources in treatment of petroleum deposits by the bacterial strain BBRC9012
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Roostaazad, R ; Yaghmaei, S ; Sharif University of Technology
2006
Abstract
Effect of several auxiliary carbon sources such as crude oil, different precultures, and quality of adding crude oil in treatment of petroleum wax deposits by an isolated bacterial strain, BBRC9012, was investigated. First and second experiments which compered effect of molasses, glucose and crude oil, indicated that glucose and molasses causes more microbial growth, biosurfactant production and bioemolsification than crude oil. Both optometry and Surface tension measurements showed that using molasses-BHB preculture for wax treatment is not suitable and when crude oil is used as auxiliary carbon source a one day lag phase is unavoidable. It was also shown that when crude oil is added to...
A comprehensive study on the complete charging-discharging cycle of a phase change material using intermediate boiling fluid to control energy flow
, Article Journal of Energy Storage ; Volume 35 , 2021 ; 2352152X (ISSN) ; Mohammadi, O ; Faghiri, S ; Shafii, M. B ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The low melting and solidification rates of phase change materials (PCM), which traces back to their low thermal conductivity coefficient, has led the application of these materials to face limitations. This paper aims to explore the effectiveness of a novel method called intermediate boiling fluid (IBF) in speeding up the energy storage and transfer processes in PCMs during a complete charging-discharging cycle. Throughout this novel technique, paraffin and acetone are utilized as PCM and IBF, respectively. In the solidification process, there is no direct contact between the cold source and the molten paraffin, while acetone, as an intermediate fluid, is being boiled via absorbing...
Experimental determination of equilibrium interfacial tension for nitrogen-crude oil during the gas injection process: The role of temperature, pressure, and composition
, Article Journal of Chemical and Engineering Data ; Vol. 59, issue. 11 , September , 2014 , p. 3461-3469 ; ISSN: 00219568 ; Ayatollahi, S ; Zolghadr, A ; Ghazanfari, M. H ; Masihi, M ; Sharif University of Technology
Abstract
Nitrogen has emerged as a competitive gas injection alternative for gas-based enhanced oil recovery processes in the past two decades. The injection of nitrogen into the reservoirs has improved the oil recovery efficiency in various oil reservoirs from heavy to volatile oils. As it is known, interfacial tension (IFT) plays a key role in any enhanced oil recovery process, particularly gas injection processes; therefore, its accurate determination is crucial for the design of any gas injection process especially at reservoir condition. In this study, an axisymmetric drop shape analysis (ADSA) was utilized to measure the equilibrium IFTs between crude oil and N2 at different temperature levels...
Experimental investigation of paraffin nano-encapsulated phase change material on heat transfer enhancement of pulsating heat pipe
, Article Journal of Thermal Analysis and Calorimetry ; Volume 137, Issue 5 , 2019 , Pages 1603-1613 ; 13886150 (ISSN) ; Shafii, M. B ; Rezaee Shirin Abadi, A ; Ghasempour, R ; Alhuyi Nazari, M ; Sharif University of Technology
Springer Netherlands
2019
Abstract
In this study, a mixture of nano-encapsulated phase change materials in water has been used as the working fluid in a pulsating heat pipe in order to investigate its thermal performance. The results of the experiments showed that using the nano-encapsulated paraffin dispersed in water as working fluid improves heat transfer and decreases the thermal resistance of the pulsating heat pipe. On the other hand, among the tested concentrations for nano-encapsulated paraffin, there is an optimal value in which increasing the concentration causes an increase in the thermal resistance of the pulsating heat pipe due to the increased dynamic viscosity of the fluid. Enhancement in the thermal...
Super-fast discharge of phase change materials by using an intermediate boiling fluid
, Article International Communications in Heat and Mass Transfer ; Volume 115 , 2020 ; Mohammadi, O ; Rahgozar, I ; Shafii, M. B ; Ahmadi, M. H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The low thermal conductivity of phase change materials (PCM) results in the slowdown in the discharging process of PCM which limits the usability of these materials in the field of Thermal Energy Storage (TES). In this research, an innovative solution is proposed to significantly accelerate the solidification speed, up to two orders of magnitude greater than conventional methods. Using acetone as the intermediate boiling fluid (IBF), the paraffin discharge rate as a phase-change material is significantly improved which is known as super-fast discharge (SFD) in this article. In this method, liquid acetone takes the heat by boiling in liquid paraffin and causes it to solidify. As the liquid...
Study and optimization of amino acid extraction by emulsion liquid membrane
, Article Separation Science and Technology ; Volume 43, Issue 11-12 , 2008 , Pages 3075-3096 ; 01496395 (ISSN) ; Alemzadeh, I ; Vossoughi, M ; Sharif University of Technology
2008
Abstract
A batch extraction of an essential amino acid, phenylalanine, from an aqueous solution of different concentrations by an Emulsion Liquid Membrane (ELM) was developed using D2EHPA as a cationic carrier, Span 80 as the surfactant, paraffin, and kerosene as the diluents, and HCl as the internal electrolyte. All effective parameters such as the initial pH of the aqueous external phase, the electrolyte concentration in the aqueous internal phase, carrier, and surfactant concentration in the emulsion, the volume ratio of the organic to aqueous internal phase (Roi), the volume ratio of the W/O emulsion to the aqueous external phase (Rew) and time were examined and optimized using the Taguchi...
Experimental Investigation of Paraffin Nano-encapsulated Phase Change Material on Heat Transfer Enhancement of Pulsating Heat Pipe
, M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad (Supervisor) ; Rezaee Shirin-Abadi, Abbas ($item.subfieldsMap.e) ; Ghasempour, Roghayeh ($item.subfieldsMap.e)
Abstract
In this study, a mixture of nano-encapsulated phase change materials in water has been used as a working fluid in a pulsating heat pipe in order to investigate its thermal performance. The results of the experiments showed that using the nano-encapsulated paraffin dispersed in water as working fluid improves heat transfer and decreases the thermal resistance of the pulsating heat pipe. On the other hand, there is an optimal concentration among tested concentrations for nano-encapsulated paraffin, in which increasing its concentration due to the increased dynamic viscosity of the fluid causes an increase in the thermal resistance of the pulsating heat pipe. Enhancement in the thermal...
Experimental Investigation Into the Performance of Pulsating Heat Pipe Using Nano-Encapsulated Phase Change Material Along with Rgo Nanosheets
, M.Sc. Thesis Sharif University of Technology ; Shafii, Mohammad Behshad (Supervisor) ; Rezaee Shirin-Abadi, Abbas (Co-Supervisor)
Abstract
Heat pipes are useful devices in heat transfer, renewable energies and cooling systems in particular. According to various application of this systems in different industries, performance improvement of this devices has gained much importance. Working fluid is one of the effective factors on pulsating heat pipes. Since heat transfer in PHPs is natural convection and two-phase, specific heat and thermal conductivity of working fluid have an important role in the performance of pulsating heat pipes. In the present study, the effect of using nano-encapsulated PCM along with reduced graphene oxid (RGO) dispersed in water and their mixture as working fluid has on the performance of PHPs has been...
Mathematical Modeling of Fixed bed Reactor for Oxidative Dehydrogenation (ODH) Process of Light Paraffins
, M.Sc. Thesis Sharif University of Technology ; khorashe, Farhad (Supervisor)
Abstract
An industrial scale reactor for light olefinsproduction was modelledusing the oxidative dehydrogenation (ODH) of light paraffinsin a multi-tubular reactor system involving 10000 small diameter tubes immersed in a shell with proper liquid-cooled flows. Here a theory-based pseudo-homogeneous 1-D model describing the operation of a fixed bed reactor for the ODHparaffinstoolefins over a Ni-Nb-O mixed oxide catalyst (for ethane) and over a V2O5/γ-Al2O3catalyst (for Propane),was employed. The paraffin and oxygen conversions, gas process and coolant temperatures, as well as other parameters affecting the reactor performance, including pressure, were examined. Furthermore, the applied model showed...
Kinetic Modeling of Thermal Hydrocracking of a Paraffinic Feedstock
, M.Sc. Thesis Sharif University of Technology ; Khorasheh, Farhad (Supervisor) ; Badakhshan, Amir (Supervisor)
Abstract
Hydrocracking is a hydrogen addition process that permits refineries to convert heavier, less expensive crudes, into highly-valued transportation fuels such as gasoline, kerosene and diesel. Development of an accurate kinetic model for hydrocracking reactions is crucial to correctly predict the detailed product distribution under different operating conditions for a range of feedstocks as well as for reactor design, process optimization and catalyst selection. In this thesis a mechanistic kinetic model was developed for thermal hydrocracking of a paraffinic feedstock. This model was based on a molecular approach that was able to capture the fundamental chemistry of hydrocracking process. To...