Kinetic Modeling of Propane Dehydrogenation on Industrial Pt-Sn/γ-Al2O3 in Presence of Oxygenated Compounds

, M.Sc. Thesis Sharif University of Technology Barghi, Bijan (Author) ; Khorasheh, Farhad (Supervisor)

Abstract

The study on the propane dehydrogenation process has been receiving significant attention due to the growing demand for propylene. The aim of this research is to develop an appropriate kinetic mechanism for dehydrogenation of propane over an industrial Pt–Sn/γ-Al2O3 catalyst in the presence of a very small amount of water. The reaction is carried out over the temperature range of 575 – 620 º C at atmospheric pressure. The results showed that a small amount of water and methanol can improve the performance of catalyst and also, increase the selectivity to COx. Addition the 0.5, 0.45, 0.3 water and 0.1, 0.05, 0.02 methanol are the optimum amount of these oxygenated compounds in order at...

Exact and Metaheuristic Solution for Multi-skilled Project Scheduling Problem with Regards to Set-up Time

, M.Sc. Thesis Sharif University of Technology Barghi, Behrad (Author) ; Shadrokh, Shahram (Supervisor)

Abstract

Multi-mode resource-constrained project scheduling problem (MRCPSP) is considered one of the most complex and most frequently applied problems in the science field of project scheduling and the science of operations research, which recently a new version of it called multi-skilled project scheduling problem (MSPSP) has emerged in research studies. The purpose of this new problem is to schedule activities with respect to precedence relationships and resource constraints of the workforce types with multiple skills, such that the requirements of any activity for a subset of skills must be met by the qualified members of the project. In this study, in addition to observing the constraints and...

Qualitative and quantitative project risk assessment using a hybrid PMBOK model developed under uncertainty conditions

, Article Heliyon ; Volume 6, Issue 1 , 2020 Barghi, B ; Shadrokh sikari, S ; Sharif University of Technology

Elsevier Ltd 2020

Abstract

This study presented a qualitative and quantitative project risk assessment using a hybrid PMBOK model developed under uncertainty conditions. Accordingly, an exploratory and applied research design was employed in this study. The research sample included 15 experienced staff working in main and related positions in Neyr Perse Company. After reviewing the literature and the Project Management Body of Knowledge (PMBOK), 32 risk factors were identified and their number reduced to 17 risks using the expert opinions via the fuzzy Delphi technique run through three stages. The results of the confirmatory factor analysis showed that all risks were confirmed by the members of the research sample....

Performance analysis and comparison of coded FH/MC-CDMA and MC-CDMA communication system

, Article 18th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC'07, Athens, 3 September 2007 through 7 September 2007 ; December , 2007 ; 1424411440 (ISBN); 9781424411443 (ISBN) Barghi, S ; Nasiri Kenari, M ; Sharif University of Technology

2007

Abstract

In this paper, we will combine the frequency hopping (FH) and the multi-carrier code division multiple access scheme (MC-CDMA) through an internal coding. The total bandwidth will be divided to a number of sub-bands with equal bandwidth. In each signalling interval, the output of a super orthogonal encoder selects one of the sub-bands for data transmission. Sub-carriers are modulated by a user specific PN sequence, and are transmitted over the selected sub-band similar to the MC-CDMA communications. We will derive the exact bit error rate of the MC-CDMA system and the new coded system. It will be shown by analysis and simulation that the proposed system performs much better than the MC-CDMA...

Meta-heuristic solution with considering setup time for multi-skilled project scheduling problem

, Article Operations Research Forum ; Volume 3, Issue 1 , 2022 ; 26622556 (ISSN) Barghi, B ; Sikari, S. S ; Sharif University of Technology

Springer International Publishing 2022

Abstract

The authors consider the Multi-Skilled Project Scheduling Problem (MSPSP) as a version of the Multi-mode Resource-Constrained Project Scheduling Problem (MRCPSP), which extends the well-known NP-hard Resource-Constrained Project Scheduling Problem (RCPSP). In the MSPSP, it is made up of activities, which require specific skills to be done. Moreover, resources are staff members who master fixed skill(s). Thus, each resource requirement of an activity corresponds to the number of persons doing the corresponding skill that must be assigned to the activity during its whole processing time. The authors focus on taking into account the setup times when performing work, depending on the appointment...

The modeling of kinetics and catalyst deactivation in propane dehydrogenation over Pt-Sn/γ-Al2O3 in presence of water as an oxygenated additive

, Article Petroleum Science and Technology ; Vol. 32, issue. 10 , Mar , 2014 , pp. 1139-1149 ; ISSN: 10916466 Barghi, B ; Fattahi, M ; Khorasheh, F ; Sharif University of Technology

2014

Abstract

A reduction in catalyst's activity with time-on-stream and the formation of side products are two of the problems associated with catalytic propane dehydrogenation (PDH). Previous studies have indicated that the presence of small amounts of oxygenated additives such as water can reduce coke formation and enhance catalyst activity. The aim of the present work was to develop an appropriate kinetic model for PDH over a commercial Pt-Sn/γ-Al 2O3 catalyst in the presence of small amounts of water. Experimental data were obtained from a previous study where catalytic PDH was carried out in a bench scale reactor system at atmospheric pressure in the temperature range of 575-620°C in the presence of...

Kinetic modeling of propane dehydrogenation over an industrial catalyst in the presence of oxygenated compounds

, Article Reaction Kinetics, Mechanisms and Catalysis ; Volume 107, Issue 1 , 2012 , Pages 141-155 ; 18785190 (ISSN) Barghi, B ; Fattahi, M ; Khorasheh, F ; Sharif University of Technology

Springer 2012

Abstract

The aim of this study was to develop an appropriate kinetic model for propane dehydrogenation (PDH) over an industrial Pt-Sn/γ-Al 2O 3 catalyst in the presence of small amounts of oxygenated compounds. Experimental data were obtained from a previous study where catalytic PDH was carried out in a laboratory scale reactor at atmospheric pressure in the temperature range of 575-620 °C in the presence of small amounts of water or methanol. The kinetics of the main dehydrogenation reaction was described and the effects of water and methanol on coke deposition and catalyst sintering were considered in a catalyst deactivation model to explain the observed optimum level in the amount of added...

An experimental study on permeability, diffusivity, and selectivity of CO2 and CH4 through [bmim][PF6] ionic liquid supported on an alumina membrane: Investigation of temperature fluctuations effects

, Article Journal of Membrane Science ; Volume 362, Issue 1-2 , 2010 , Pages 346-352 ; 03767388 (ISSN) Barghi, S. H ; Adibi, M ; Rashtchian, D ; Sharif University of Technology

2010

Abstract

In order to define a new temperature correction factor in this study, accurate experimental values were presented for permeability and diffusivity of carbon dioxide and methane in imidazolium-based room temperature ionic liquid: [bmim][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate) immobilized on an inorganic membrane support. Results were presented as a function of temperature and pressure for temperatures within 300-320K and pressures below 50kPa. According to the literature, experimental values of permeability and diffusivity for CH4 in [bmim][PF6] vs. temperature are reported for the first time in this study. Results obtained for CO2 permeability revealed good agreement with data...

Design of a Fault Tolerant ARM-Based Processor on FPGA

, M.Sc. Thesis Sharif University of Technology Esmaeeli, Siamak (Author) ; Rashidian, Bijan (Supervisor) ; Vosughi Vahdat, Bijan (Supervisor)

Abstract

The charged particles in space strike the silicon surface of an embedded system in a satellite and cause fault occurrence in its operation. So some methods should be employed to reduce the effects of the faults. The methods that are implemented in system level are widely used because of their low cost and high reliability. The processors are responsible for performing main processes in embedded systems. On the other hand, the ARM processors are good choices for utilizing in satellites because of their low size, low power consumption and high performance. Also, FPGAs have made a major improvement in embedded system design. So with implementing ...

Design of a Fault Tolerant SPARC Based Micro Processor On FPGA

, M.Sc. Thesis Sharif University of Technology Hosseini, Morteza (Author) ; Rashidian, Bijan (Supervisor) ; Vosoughi Vahdat, Bijan (Supervisor)

Abstract

In this thesis, LEON Processor was chosen for its compatible architecture that can be implemented on a wide range of FPGAs. The final designed processor is aimed to conquer soft and hard errors that occur due to cosmic radiations in SRAM cells of an FPGA. The system can finally resist all single SEUs that happen in flip flops and all 4 random errors that take place in each register of the register file. All the flip flops and latches are protected using a TMR scheme. The information redundancy in the regiester file to overcome all 4 random errors is 168% and the errors are corrected by means of a mechanesim that is masked from the processor core. In cache memory, each 32 bit data is...

Low Grade Heat Driven Multi-Effect Distillation and Desalination

, Book Rahimi, Bijan ; Chua, Hui Tong

Elsevier 2017

Abstract

Low Grade Heat Driven Multi-effect Distillation and Desalination describes the development of advanced multi-effect evaporation technologies that are driven by low grade sensible heat, including process waste heat in refineries, heat rejection from diesel generators or microturbines, and solar and geothermal energy. The technologies discussed can be applied to desalination in remote areas, purifying produced water in oil-and-gas industries, and to re-concentrate process liquor in refineries.
This book is ideal for researchers, engineering scientists, graduate students, and industrial practitioners working in the desalination, petrochemical, and mineral refining sectors, helping them...

Simulation of New Methods in Ventilation of Underground Station Sand Tunnels

, M.Sc. Thesis Sharif University of Technology Adibi, Omid (Author) ; Farhanieh, bijan (Supervisor)

Abstract

Due to growth of the number of passengers in subway transportation systemsthe capacity of the metro stations are on the rise.The generated heat loads in subway line shall be increased by thegrowth of the its capacity. As a result, current subway ventilation systems cannot provide comfort conditions for passengers. Nowadays, modern ventilation systems are designedto improve ventilation performance and to create suitable thermal conditions. Among of these, the under platform andover track exhaust systems and use of platform screen doors can be Cited. The aim of this study is three-dimensional simulation of air flow in modern ventilation systems of subway stations. Numerical simulations are in...

Numerical Simulating of a Railcar fire in Tunnel

, M.Sc. Thesis Sharif University of Technology Pourghasemi, Mahyar (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Fire phenomenon and its hazards through urbun transportation systems like subway is a major debate in management of these territories. Recently, varios factors, such as great deal of passengers whom travel by these systems, financial damages and psychological disorders due to fire accidents resulte in noticeable investigation to prevent and reduce these subjects. In this research, simulating of railcar fire has been conducted to estimate the amount of heat release rate (HRR) and parameters which affect on it by modelling behavior of combustible materials inside railcar. As regards to materials which are available inside railcar that participate in fire, their behavior face to heat flux has...

Simulation of Fire in Tunnels Using Fire Dynamics Simulator Code (FDS)

, M.Sc. Thesis Sharif University of Technology Shahsavan, Martia (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Designing of an efficient emergency ventilation system is one of the main approaches to prevent the perilous fire in tunnel phenomenon. For this purpose, firstly, fire behavior and its heat release rate should be investigated. Knowing about temperature distribution and smoke movement is the second step. One of the most considerable factors in smoke control is critical velocity. It means the minimum velocity to prevent backlayering flow. If longitudinal ventilation velocity were less than this amount, smoke and hot gases originated from the fire can enter the upstream zone. This may cause lack of oxygen and decrease visibility for the passengers when they are escaping from the fire field. In...

Numerical Investigation of Turbulent Flow Inside De-Oiling Hydrocyclones Using Large Eddy Simulation Approach

, M.Sc. Thesis Sharif University of Technology Saeedi, Maysam (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Hydrocyclones are used for separating different materials from liquids in a variety of applications. Compactness, efficiency, reliability and low maintenance costs are their noteworthy characteristics. Dewatering and deoiling hydrocyclones used for refining crude oil or oily waste water in offshore platforms are examples of liquid-liquid hydrocyclones. Separation process in hydrocyclones is based on the fact that swirl flow induces a centrifugal force and leads to separation due to density difference. The density difference in liquid-liquid mixtures is smaller than solid-liquid types and trying to separate one liquid from another takes much more effort than the other type. Increase of...

Thermionic Emission Properties of Oxide Based Nano-Structures

, M.Sc. Thesis Sharif University of Technology Heydarian, Hesam (Author) ; Rashidian, Bijan (Supervisor)

Abstract

For years, in thermionic emission, a great deal of scientists’s effort has been devoted to the search for low work function materials with high melting temperature. In this way, high brightness and long life are the central targets of emission material investigations. In addition, high current density and low power consumption are the guiding principles for some applications.
In first part of this thesis, basic electron emission theories, fabrication methods of thermionic emission, effect of different parameters on the electron emission properties of thermionic emitters and applications of them are investigated. After setting up fabrication methods of S type cathode, in the second part...

Deposition of Nanoporous Metallic Thin Films by Sputtering and Comparing with Electrochemical Method (Electroplating)

, M.Sc. Thesis Sharif University of Technology Monjezi, Hossein (Author) ; Rashidian, Bijan (Supervisor)

Abstract

Porous thin films have becom very atractive due to their applications in many types of electronic and optical devices. There are several methods for deposition of such films. Chemical method for deposition of nanoporous thin films are relatively simple, but usually hard to control. In this thesis, chemical deposition of thin porous Molybden films is reported. In addition, an available sputtering system has been modified and, controlled porosity thin films were then deposited on glass and silicon substrates using GLAD method.These films have been characerized, and compared with chemically deposited porous thin films

Evaluation and Simulation of Tunnel Mid-shaft Effects on the Natural and Normal Ventilation Performance in a Subway Tunnel

, M.Sc. Thesis Sharif University of Technology Mahmoodi, Ghasem (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Necessity of a public transport network, environmental protection and a highly land cost in urban areas have increased the desire for underground transportation systems. On the other hand, ventilation system design should be done precisely specially for longer tunnels, large undergrounds spaces and crowded places. Rate of energy reduction for vent systems operation is dependent on their proper implementation. Tunnel design efficiently is influenced by ventilation system. The tunnel mid shaft is complementary part of the underground railway systems that is required for exchange air between the tunnel and the railway station with ambient fresh air. An important application of the tunnel mid...

Simulating Firefighting Scenarios in Enclosures

, M.Sc. Thesis Sharif University of Technology Amiri, Pezhman (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Fire in enclosures is one of the most important disasters due to the presence of human and physical risks, so, investigation of the firefighting scenarios in this case has much importance. In the present study, novel enclosures fire suppression scenarios are simulated using computational fluid dynamics (CFD). The simulations have two major categories. In the first part, performance of different natural ventilation, positive pressure ventilation (PPV) and negative pressure ventilation (NPV) scenarios, which are new methods in firefighting, are evaluated and compared. In this part, the influence of different parameters like geometry, position of inlet and outlets and fire heat release rate...

Modeling of Urban Air Pollutants Dispersion

, M.Sc. Thesis Sharif University of Technology Moradpour, Mrayam (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Air pollution is lateral and inappropriate product of industry and technology development that grows along them, unfortunately. Now its domain extended from local and national issues to global issues. For years like other branches of environmental sciences and other scientific fields, scientists apply formulas and mathematical equations. Nowadays, air pollution modeling is fundamental and powerful tool for air pollution studies, especially in prediction of air pollution conditions, pollutants emission and their concentration under different conditions and arbitrary locations. In this research, numerical modeling of urban air pollutants dispersion is discussed. After validation of results,...