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Preparation of Membrane Contactor for H2S, CO2 and CH4 Separation
, M.Sc. Thesis Sharif University of Technology ; Roosta Azad, Reza (Supervisor) ; Moosavi, Abbas (Supervisor)
Abstract
Recently separation technology has been developed and engineers are trying to find more rapid and more economic ways in order to reach pure materials. One of the most important needs of human being is natural gas which has some impurities. Acid gases such as carbon dioxide and hydrogen sulfide must be separated from methane. This operation is called gas sweetening. Membrane contactors are equipments recently developed and may be used instead of packed towers for gas sweetening in the future. In this project we designed and made a membrane contacting unit to separate carbon dioxide and hydrogen sulfide from methane. This unit lets you to study the effect of many parameters such as gas and...
Investigation of Aligned Carbon Nanotubes Modified by Platinum Nanoparticles as Hydrogen Sulfide Sensor
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor) ; Ghorbani, Mohamad (Supervisor)
Abstract
The present research describes sensing behavior of modified aligned carbon nanotubes toward detection of hydrogen sulfide. Aligned carbon nanotubes were grown on etched stainless steel by thermal chemical vapor deposition. Obtained CNTs have curved closed tips and bamboo like structure. Purification of carbon nanotubes were performed by electrochemical oxidation of CNTs. Potential cycling was applied on grown CNTs in different acid solutions and 0.2 M sulfuric acid was chosen to oxidize the CNTs. Carboxylic functional groups were produced by electrochemical oxidation of CNTs and can be observed in FTIR studies. These groups enhanced the electrochemical properties of electrodes and may act as...
Doping Effect of Copper and Copper Oxide on H2S Sensing of Nanostructured WO3
, M.Sc. Thesis Sharif University of Technology ; Iraji Zad, Azam (Supervisor)
Abstract
The aim of this research is preparation of tungsten trioxide nanoparticles film for hydrogen sulfide gas sensing. These nanoparticles were made by simple and inexpensive sol-gel method. To improve gas sensing properties, various precursors of copper and copper oxides were added to the sol. This solution was coated on alumina substrate by spin coating method. After annealing, sensing properties of samples were studied by measuring the electrical resistance. Best precursor and its molar percentage of copper to tungsten were selected (WO3-Cu2O (1%)). All tests for this sample were done in temperatures below 100 °C and gas concentration lower than 10 ppm. Sensitivity of WO3-Cu2O (1%) to 1 ppm...
Synthesis and Characterization of Nano-zeolite Membranes for Natural Gas Sweetening
, Ph.D. Dissertation Sharif University of Technology ; Soltanieh, Mohammad (Supervisor)
Abstract
Zeolite membranes are of interest due to their special properties; thermal and mechanical resistances and non-plasticization property in gas separations. Therefore, separation of H2S from natural gas by these membranes is the main goal of this thesis which is not investigated in the world. After some theoretical investigations including diffusion mechanisms of gases in the zeolites and adsorption mechanism of H2S on the zeolites, pure silica CHA-type (Si-CHA) zeolite was selected. After successful synthesis of Si-CHA zeolite, adsorption isotherms of H2S, CO2, and CH4 on the Si-CHA zeolite were measured over pressure range of 0-190 kPa and temperatures of 25 °C, 50 °C, and 75 °C. Acid gases...
The investigation of Odor Producing Factors in Kish Island Refineries and Sewage Collection System
,
M.Sc. Thesis
Sharif University of Technology
;
Hashemian, Jamal
(Supervisor)
Abstract
From the main factors causing an unpleasant odor can refer to indoles, askatels, mercaptans, some volatile organic compounds, sulfide hydrogen, ammonia, and the number of odor-causing compounds, which are also found in the wastewater facilities and sometimes produce unpleasant odors. Meanwhile, ammonia (Pungent and irritating odor) and sulfide hydrogen (colorless poisonous gas with the odor of rotten eggs) can be presented as major factors in sewage odor.
Several factors are involved in the foul-smelling hydrogen sulfide gas collection system and wastewater treatment. A few of them include numerous sewage pumping stations, selected the appropriate gradient in the collection system,...
Several factors are involved in the foul-smelling hydrogen sulfide gas collection system and wastewater treatment. A few of them include numerous sewage pumping stations, selected the appropriate gradient in the collection system,...
Kinetic of Zinc Sulfide Roasting of
, M.Sc. Thesis Sharif University of Technology ; Halali, Mohammad (Supervisor)
Abstract
In this study, the effect of two main parameters, time and temperature, were investigated in the roasting process of zinc sulfide of Bafgh’s mine, and kinetics and the mechanism of the roasting reaction were examined, too. The oxidation process was performed in a muffle furnace in the presence of the oxygen of air atmosphere. The raw powder material (with the particle size of 74-250 micron) was poured in Alumina crucibles. The roasting process was run in eight temperatures of 650, 700, 750, 800, 850, 900, 950 and 1000 ◦C. Oxidation percent was calculated in six times of 5, 10, 15, 30, 45 and 60 minutes. The experiments were designed in a way that the effect of each parameter could be...
H2S Gas Sensing Characterization of Nano-Structured SnO2-CuO Multilayer Sensor
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Co-Advisor)
Abstract
Hydrogen sulfide, H2S, is a toxic gas and has detrimental effects on human health and the oil and gas industry. Therefore, its identification is very important. According to the devastating effects of this gas, then, the general mechanisms have been studied for gas detection. In addition, by highlighting the benefits of the multilayer nanostructure electrochemical sensors, an applicable and efficient method for the industrial production of these sensors has been investigated. In this regard, the sol-gel method is used to prepare the SnO2-CuO multilayer thin film and the advantages of this method was compared to PVD method. Also sensor properties of both deposition methods have been...
Fabrication of Nano Sensor for Detecting H2S
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor) ; Rashidi, Alimorad (Supervisor) ; Izadi Yazdan Abadi, Nosrat (Co-Advisor)
Abstract
Due production and use of large amount of chemical and emissions of pollutants in air, detection and control of these compounds are necessary. One of the common methods to detect these pollutants in the ambient is using metal oxide semiconductor sensors. However, these types of sensors suffer from low selectivity toward a certain compound in the mixture of different gas components. In this study, the object was to investigate the effect of different amount of CNTs on performance of tin oxide to improve their selectivity for detection of 50 ppm of hydrogen sulfide at low temperature. To perform the study, nanoparticles of pure tin oxide and SnO2 base hybrids containing 0.25wt%, 0.5wt%, 2.5wt%...
Nanocarbon-based Nanocatalyst Design & Synthesis for Hydrogen Sulfide Removal from Gas Feed
, M.Sc. Thesis Sharif University of Technology ; Baghalha, Morteza (Supervisor) ; Eskandari, Mohammad Mehdi (Supervisor)
Abstract
well known metal-free nanostructure carbon-based catalyst, mesoporous graphitic carbon nitride, with diverse morphologies were synthesized by using ethylendiamine/carbontetrachloride as a precursor, SBA-15 and SBA-15 nanorod as hard templates. We have investigated morphology effect on the catalytic performance. The catalysts were characterized by means of low angle and wide angle XRD, BET, FT-IR, CHNOS, FE-SEM analysis. Because of high surface area, pore volume and high nitrogen content, which acts as lewis basic site, for the first time, carbon nitride is chosen for selective catalytic oxidation of hydrogen sulfide to sulfure. Reaction was taken place in a fixed-bed reactor and at...
Creating a Protective Coating Against Corrosion and Erosion on the Surface of the Parts using in Sour Environments
, M.Sc. Thesis Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor)
Abstract
A concern in the production sour oil and gas is the corrosion caused by the acid gas H2S. Even though corrosion resistant alloys (CRA) have long been available as a material selection option that mitigates H2S corrosion, the carbon steel is in general more cost-effective for oil and gas facilities. The aim of this study is to investigate the mechanical properties of 410NiMo cladding on a low alloy steel substrate. In this investigation, two successive layers of ER410NiMo were clad on low alloy steel substrates. To reduce the likelihood of Hydrogen Induced Cracking (HIC) and producing stable hydrogen traps, Post Weld Heat Treatment (PWHT) was used. To characterize the mechanical properties of...
Preparation of Nanocomposite Membrane For H2S / CH4 Separation
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor) ; Khanbabaee, Ghader (Supervisor) ; Babana’lbandi, Ahmad (Co-Advisor)
Abstract
Due to the presence of carbon dioxide and hydrogen sulfide in natural gas outlet of wells, it cannot be sent directly to the municipal pipelines. This study was trying to be select and made membranes for separation of CO2 and H2S from methane. Permeability of methane and carbon dioxide gases through the polyurethane membranes were studied. For this purpose, two commercial polyurethane and synthesized polyurethane with different formulations of the compounds that have been studied so far in the literature were used. Synthesized polyurethane and nano-composite membranes were characterized by using Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and Fourier Transfer...
Preparation of Nanocomposites from Carbon Nanostructures and Transtion Metal Oxides and their use in Preparation of Hybrid Electrochemical Capacitors
, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed (Supervisor)
Abstract
In the first part, we report a new and simple procedure for preparing reduced graphene oxide /nickel, cobalt hydroxide composite (Ni,Co-OH/rGO/NF via a fast and simple two-step electrochemical method including potentiostatic routes in the presence of Cetyl trimethyl ammonium bromide )CTAB( as a cationic surfactant. In the first step, a piece of nickel foam (NF) is sonicated in a suspension of graphene oxide (GO, 6 mg/L) after dried in an oven, reduced by electrochemically. After that, Ni, Co LDH were co-deposited on the surface of rGO/NF. The resulting modified electrode afforded extremely high specific capacitance of 2133.3 F/g at a current density of 4 A g-1. FE-SEM results showed that...
Study of Effective Parameters on Roasting of Zinc Sulphide in a Fluidized Bed Reactor
, M.Sc. Thesis Sharif University of Technology ; Halali, Mohammad (Supervisor)
Abstract
In this study, four parameters were investigated including temperature, inlet flow rate, gas composition (oxygen) and particle size on the roasting of Bama company zinc sulfide concentrate in Fluidized bed reactor. Initially, primary sample was heated in electric furnace at 125℃ for 24 hours until the moisture content dried. Then roasting operation was done at 700 and 900℃. The operation was carried out on three range of particle size including 300-500, 500-700 and 700-1000 microns and flow rate was greater than the minimum flow rate of Fluencing. To investigate the effect of flow rate and gas composition input, 500-700 micron particle size range was selected. The effect of 155, 172 and 188...
Surface Passivation of PbS Colloidal Quantum Dots for Photovoltaic Applications
, Ph.D. Dissertation Sharif University of Technology ; Simchi, Abdolreza (Supervisor) ; Ashuri, Hossein (Supervisor)
Abstract
Solution-processed quantum dots (QDs) have attracted significant attention for the low-cost fabrication of optoelectronic devices. Here, we synthesized PbS QDs via hot injection method and passivated the trap states by using short thiols and dopant elements for photovoltaic application. In order to study the effect of dopants on photovoltaic application, PbS QDs were doped by using three different cations: Cadmium, Calcium, and Zinc. The results showed that Cd dopant has a better improvement than Ca and Zn dopants in order to increase the efficiency of the PbS QDs solar cells. We achieved solar power conversion efficiencies of 5.81% using Cd therapy. Recently, hybrid nanocomposites...
Synthesis and Characterization of ZnO Nanostructure, Modified by Graphene and CdS for PEC Application
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor)
Abstract
In this project, the photoelectrochemical properties of ZnO nanostructures modified by CdS and Graphene was studied. Firs, titanium foil was cut into rectangular shape with 1cm width and 3 cm length, cleaned by rinsing in acetone and ethanol and annealed at 4000C for an hour. As a result, a thin layer of titanium oxide was formed on Ti sheet. Then a layer of grapheme oxide was deposited on substrate using Electrophoretic deposition (EPD). After that, ZnO nanostructure was deposited on the TiO2 substrate using Electropulsation (EP) with 20 consecutive pulse followed by 3 minutes Electrodeposition (ED). Using SEM analysis, the morphology of ZnO was determined to be nanopetals in which the...
Synthesis, Characterization and Studying of Photoelectrochemical (PEC) Properties for TNA/Ag2S Nanostructures
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Ali Reza (Supervisor) ; Moradlo, Omran (Co-Advisor)
Abstract
Free-standing TiO2 nanotube array (TNA) films were fabricated via two-step anodization of titanium sheet. The electrolyte consisted of DI water and ethylene glycol (99.9%, Merck) solution with volume ratio of 10:90, containing 0.5 M NH4F. Then, a few drops of 1M H3PO4 aquaes solution have been added to adjust pH at 5.7. The anodization process was performed at optimized applied voltage of 60 V for 200 min. Indeed it does in two-step for 50 and 150 min, and samples were sonicated of 40s between two steps. Then, to crystallize the grown structures, they were annealed in air at 500˚C for 80 minutes. Surface of TNA was modified by sequential-chemical bath deposition (S-CBD) method to fabricate...
Deposition of CdS on Nanostructured and Mesoporous TiO2 Film for Solar Cell Application
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
In this project, The cadmium sulfide nanoparticles were formed on a nanostructured and meso-porous titanium dioxide layer and its properties were characterized. Deposition process of titanium dioxide and cadmium sulfide has been performed respectively in one stage and two stages of dipcoating. In order to probing effects of temperature and dipcoating time, samples have been prepared in various times and temperatures. Also, some of the samples have been annealed. Thickness of titanium dioxide and cadmium sulfide coatings were approximately measured 1 μm and between 3-5 μm, respectively. As expected, XRD results disclosed that cadmium sulfide and titanium dioxide were formed in the form of...
Development of Ratiometric Sensors Based on Fluorescent Nanostructures for Naked Eye Detection
, Ph.D. Dissertation Sharif University of Technology ; Hormozi-Nezhad, Mohammad Reza (Supervisor)
Abstract
In the first part of this research, we have developed a simple and effective ratiometric fluorescence sensor for selective detection of dopamine (DA) in alkaline media by simply mixing thioglycolic acid (TGA) functionalized orange fluorescent cadmium telluride (CdTe) quantum dots (QDs) with amino-functionalized blue fluorescent carbon nanodots (CDs). Under a single excitation wavelength of 365 nm, the sensor exhibits dual-emissions centered at 445 and 603 nm. The fluorescence of CdTe QDs is selectively quenched by DA, whereas the fluorescence of CDs is insensitive to the analyte. In the presence of different amounts of DA, the variations in the dual emission intensity ratios exhibit a...
Safety Assessment for H2S Releasing in Arak Heavy Water Factory (GS(03) Plant) Using Probabilistic Safety Assessment Method (PSA)
, M.Sc. Thesis Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor)
Abstract
In general, release of hazardous gas in chemical process plants could be due to two reasons. First is failures due to degradation of components that have inventory of hazardous gas in standard process conditions, and the second is deviation of system from standard process conditions because of different failure modes of related components, e.g. controller equipments. The purpose of this study is, calculating the probability of H2S releasing in GS(03) plant of Arak Heavy Water factory, using PSA methods and its risk assessment. At First, fifteen groups of initiating events were identified with Hazop study for desired system. Then, for calculating the frequency of each event, the combination...
CdS:Mn and CdS:O Nanoparticles Growth via Thermochemical and Microwave Methods and Studding the Photoluminescence Properties
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
The optimization of CdS photoluminescence nanoparticles which has been considered as one of the most important II-VI semiconductors has been studied here. As the first step, synthesis parameters effect on CdS:Mn photoluminescence intensity has been regarded by thermochemical method. Effect of parameters like pH solution, heating time and capping agent concentration on photoluminescence of these materials has been experimented. What seemed so important was reaching nanoparticles with suitable nano size and nano structure and having highly photoluminescence intensity. Observing the good effect of Oxygen on photoluminescence of CdS nanoparticles leaded us to concentrate on synthesizing CdS:O...