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hydrogenation
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Economic assessment of hydrogen fueling station, a case study for Iran
, Article Renewable Energy ; Volume 33, Issue 12 , 2008 , Pages 2525-2531 ; 09601481 (ISSN) ; Shayegan, J ; Sharif University of Technology
2008
Abstract
In recent years there have been many efforts to develop a hydrogen energy system in Iran. For instance, the Iranian fuel cell steering committee conducted a project and determined some targets to implement hydrogen in different sectors, especially transportation. In this paper, the costs of building stations and the levelized cost of hydrogen for two types of stations, SMR and electrolysis, with various sizes and capacity factors have been investigated. Also, in the case of electrolysis, hydrogen cost sensitivity to the price of electricity has been examined. According to the cost analysis conducted here, it is understandable that hydrogen costs ($/kg) vary considerably based on station...
An Analytical Solution for the Polymeric Liner Collapse in Hyperbaric type IV Hydrogen Storage Vessels
, M.Sc. Thesis Sharif University of Technology ; Naghdabadi, Reza (Supervisor)
Abstract
Type IV high pressure vessels are composite vessels with a polymeric liner, which are the best choice for storing hydrogen in hydrogen vehicles. The defect of these vessels is the penetration of light hydrogen molecules in the polymeric liner and the composite part. When depressurization the vessel, these molecules cannot release from the polymeric liner and the composite part according to the emptying rate of the vessel. Thus, concentration of the hydrogen molecules in the polymeric liner becomes more than inside the vessel which leads to a pressure difference between the two sides of the polymeric liner that causes the liner collapse. In this research, the partial differential equation for...
Hydrogen, nitrogen and carbon dioxide production through chemical looping using iron-based oxygen carrier - A Green plant for H2 and N 2 production
, Article International Journal of Hydrogen Energy ; Vol. 39, issue. 20 , 2014 , pp. 10380-10391 ; ISSN: 03603199 ; Mansoori, Z ; Dabir, B ; Shahnazari, A ; Sharif University of Technology
Abstract
In order to simulate the performance of pure methane in chemical looping using iron-based oxygen carrier, simultaneously production of three pure streams of hydrogen, nitrogen and carbon dioxide has been investigated. For this purpose, proper operating conditions have been discussed for maximum production of hydrogen, complete consumption of oxygen of inlet air and complete combustion of methane. Professional software is used to simulate the chemical looping reactors and optimize their output streams. Results show that in this process each mole of methane fuel can produce 2.533, 2.65 and 0.99 mol of pure N 2, H2 and CO2, respectively which contributes 80.2% energy conversion of CH4 to H2....
Multi-objective optimization of direct coupling photovoltaic-electrolyzer systems using imperialist competitive algorithm
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Vol. 6A , November , 2014 ; Sayedin, F ; Sattari, S ; Sharif University of Technology
Abstract
Photovoltaic-electrolyzer systems are one of the most promising alternatives for obtaining hydrogen from a renewable energy source. Determining size and the operational conditions are always a key issue while coupling directly renewable electricity sources to PEM electrolyzer. In this research, the multi objective optimization approach based on an imperialist competitive algorithm (ICA), which is employed to optimize the size and the operating conditions of a directly coupled photovoltaic (PV)-PEM electrolyzer. This allows the optimization of the system by considering two different objectives, including, minimization of energy transfer loss and maximization of hydrogen generation. Multi...
Solvent polarity and hydrogen bond effects on nucleophilic substitution reaction of 2-bromo-5-nitrothiophene with piperidine
, Article International Journal of Chemical Kinetics ; Volume 43, Issue 4 , 2011 , Pages 185-190 ; 05388066 (ISSN) ; Rahmati, M ; Gholami, M. R ; Sharif University of Technology
Abstract
The reaction kinetics of 2-bromo-5-nitro thiophene with piperidine was studied in a solvent with a mixture of propan-2-ol with methanol and n-hexane at 25°C. The measured rate coefficients of the reaction demonstrated dramatic variations in propan-2-ol-n-hexane mixtures and mild variations in propan-2-ol-methanol system. The second-order rate coefficients of the reaction, kA, decreased sharply with n-hexane content. The multiparameter correlation of log kA versus molecular-microscopic solvent parameters shows interesting results in these solutions. Linear free energy relationship investigations confirm that polarity has a major effect on the reaction rate and hydrogen bond ability of the...
Morphology and magnetic properties of FeCo nanocrystalline powder produced by modified mechanochemical procedure
, Article Journal of Magnetism and Magnetic Materials ; Volume 322, Issue 21 , 2010 , Pages 3551-3554 ; 03048853 (ISSN) ; Sadrnezhaad, S. K ; Hasani, A ; Sharif University of Technology
2010
Abstract
Properties of FeCo nanocrystalline intermetallic powders prepared by salt-matrix hydrogen reduction of a milled Fe 2O 3-Co 3O 4 mixture were investigated. The product of 72 ks ball-milling at 350 rpm was CoFe 2O 4 nanopowder. Reduction of this powder for 3.6 ks by hydrogen at 750 °C resulted in the formation of Fe 0.67Co 0.33 stoichiometric compound. Scanning electron microscopy, electron dispersive spectrometry, X-ray diffraction and vibrating sample magnetometry were used to characterize the nanopowder. Using a salt-matrix (NaCl as a dispersion medium) resulted in the decrease of the reduction temperature and improvement of the morphology and magnetic properties of the nanopowder....
Graphitic carbon nitride (g-C3N4)-based photocatalysts for solar hydrogen generation: Recent advances and future development directions
, Article Journal of Materials Chemistry A ; Volume 5, Issue 45 , 2017 , Pages 23406-23433 ; 20507488 (ISSN) ; Samadi, M ; Pourjavadi, A ; Moshfegh, A. Z ; Ramakrishna, S ; Sharif University of Technology
Royal Society of Chemistry
2017
Abstract
Graphitic carbon nitride (g-C3N4) is a metal-free conjugated polymer constructed from two-dimensional sheets with a bandgap energy of 2.7 eV, which makes it an applicable and efficient visible-active photocatalyst for H2 production. In the present study, the basic concepts and principles of photocatalytic water splitting have been discussed, and a guide for the selection of appropriate photocatalysts, focusing on the g-C3N4 nanomaterials, has been proposed. Our approach is mainly concentrated on evaluating two factors, namely the solar-to-hydrogen (STH) conversion and apparent quantum yield (AQY) for different photocatalysts, to provide an in-depth analysis and a framework for solar H2...
Synergetic effect of Ni and Nb2O5 on dehydrogenation properties of nanostructured MgH2 synthesized by high-energy mechanical alloying
, Article International Journal of Hydrogen Energy ; Volume 34, Issue 18 , 2009 , Pages 7724-7730 ; 03603199 (ISSN) ; Kaflou, A ; Simchi, A ; Sharif University of Technology
2009
Abstract
Nanostructured MgH2-Ni/Nb2O5 nanocomposite was synthesized by high-energy mechanical alloying. The effect of MgH2 structure, i.e. crystallite size and lattice strain, and the presence of 0.5 mol% Ni and Nb2O5 on the hydrogen-desorption kinetics was investigated. It is shown that the dehydrogenation temperature of MgH2 decreases from 426 °C to 327 °C after 4 h mechanical alloying. Here, the average crystallite size and accumulated lattice strain are 20 nm and 0.9%, respectively. Further improvement in the hydrogen desorption is attained in the presence of Ni and Nb2O5, i.e. the dehydrogenation temperature of MgH2/Ni and MgH2/Nb2O5 is measured to be 230 °C and 220 °C, respectively. Meanwhile,...
Decolorization of reactive blue 19 dye from textile wastewater by the UV/H2O2 process
, Article Journal of Applied Sciences ; Volume 8, Issue 6 , 2008 , Pages 1108-1112 ; 18125654 (ISSN) ; Ghaneian, M. T ; Hashemian, S. J ; Moussavi, G ; Khavanin, A ; Ghanizadeh, G ; Sharif University of Technology
Asian Network for Scientific Information
2008
Abstract
Photo-oxidation of dyes is a new concern among researchers since it offers an attractive method for decoloration of dyes and breaks them into simple mineral forms. An advanced oxidation process, UV/H2O2, was investigated in a laboratory scale photoreactor for decolorization of the Reactive blue 19 (RB19 dye from synthetic textile wastewater. The effects of operating parameters such as hydrogen peroxide dosage, pH, initial dye concentration and UV dosage, on decolorization have been evaluated. The RB19 solution was completely decolorized under optimal hydrogen peroxide dosage of 2.5 mmol L-1 and low-pressure mercury UV-C lamps (55 w) in less than 30 min. The decolorization rate followed...
Hydrogen management in refineries: Retrofitting of hydrogen networks, electricity and ammonia production
, Article Chemical Engineering and Processing - Process Intensification ; Volume 157 , 2020 ; Roshandel, R ; Hamidi, A. A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
In this paper, hydrogen management in refineries is examined considering a new perspective to optimize refinery costs. In order to minimize the total annual cost in refineries a mixed-integer non-linear programming (MINLP) model has been developed. Retrofitting the hydrogen network and determining the hydrogen surplus capacity of refineries are the main outputs of the proposed model. Then, to utilize this surplus capacity and increase the profitability of refineries, surplus hydrogen is used to produce electricity and ammonia. The results of a case study showed that retrofitting of the hydrogen network can save 12% in the consumption of fresh hydrogen from hydrogen plants. After retrofitting...
A thorough analysis of renewable hydrogen projects development in Uzbekistan using MCDM methods
, Article International Journal of Hydrogen Energy ; Volume 46, Issue 61 , 2021 , Pages 31174-31190 ; 03603199 (ISSN) ; Hosseini Dehshiri, S. S ; Hosseini Dehshiri, S. J ; Almutairi, K ; Taher, R ; Issakhov, A ; Techato, K ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The energy supply system of Uzbekistan is not well positioned to meet the rapidly rising domestic energy demand of this country. Uzbekistan's current energy supply system is outdated and has very low diversity, as most of its energy comes from natural gas. In addition to producing immense amounts of greenhouse gas and environmental pollution, this situation is untenable considering the eventual depletion of fossil fuel reserves of this country. Uzbekistan's renewable energy sector is highly undeveloped, a situation that can be attributed to the lack of coherent policies for the advancement of renewable power and the low price of natural gas. However, this country has significant untapped...
Acidity enhancement of α-carbon of beta diketones via hydroxyl substituents: A density functional theory study
, Article Journal of Physical Organic Chemistry ; Volume 34, Issue 3 , 2021 ; 08943230 (ISSN) ; Fattahi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2021
Abstract
Density functional theory method and B3LYP/6-311++G(d,p) level of theory were used to determine the acidity of α-carbon in the hydroxyl derivatives of beta diketones in the gas phase. An investigation of acidity strength in the gas phase indicates that α-carbon of hydroxyl derivatives of beta diketones become stronger acids than the α-carbon of beta diketone itself as their conjugate bases gain more stability via both enolate and hydrogen bond formation. Natural bond orbital and quantum theory of atoms in molecules analyses also confirm the role of hydrogen bond interactions on increasing the acidity of α-carbon of hydroxyl derivatives of beta diketones. © 2020 John Wiley & Sons, Ltd
Theoretical investigation of the effect of hydrogen bonding on the stereoselectivity of the Diels-Alder reaction
, Article New Journal of Chemistry ; Volume 45, Issue 36 , 2021 , Pages 16760-16772 ; 11440546 (ISSN) ; Mahmoodi, M. M ; Fattahi, A ; Sharif University of Technology
Royal Society of Chemistry
2021
Abstract
In this article, we report the computational examination of the impact of hydrogen bonding (HB) on the stereoselectivity of a series of Diels-Alder (DA) reactions. Four different types of diene/dienophile couples were studied including (a) cyclopenta-2,4-dien-1-ol and heteroatom-substituted cyclopentenes, (b) substituted cyclopentadienes andN-protonated 2,5-dihydro-1H-pyrrole, (c) furan andN-protonated 5-azabicyclo[2.1.1]hex-2-ene, and (d)N-protonated cyclopenta-2,4-dien-1-amine and α,β-unsaturated carbonyl compounds. These systems were designed such that the HB can only exist in theexoreaction pathway. The optimized structures of the transition states (TSs) and products, along with the...
Facile synthesis of cotton flower like Ni–Co/Ni–Co–O–P as bifunctional active material for alkaline overall water splitting and acetaminophen sensing
, Article International Journal of Hydrogen Energy ; Volume 47, Issue 76 , 2022 , Pages 32516-32530 ; 03603199 (ISSN) ; Esfandiar, A ; Iraji zad, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The development of electrode materials with simple preparation, favorable price, excellent electrocatalytic activity, and stability are some of the most important issues in the field of electrochemistry. Herein, we prepared Ni–Co/Ni–Co–O–P cotton flower like on a copper sheet (CS) by a convenient, efficient, and scalable electrodeposition method. The Ni–Co/Ni–Co–O–P was employed as effective binder free electrode material in two different applications such as electrocatalytic water splitting and acetaminophen (APAP) sensor. Remarkably, the Ni–Co/Ni–Co–O–P@CS exhibits low overpotentials of 310 and 90 mV at 10 mA cm−2 for oxygen and hydrogen evolution reactions in alkaline media, respectively....
The decoration of TiO2/reduced graphene oxide by Pd and Pt nanoparticles for hydrogen gas sensing
, Article International Journal of Hydrogen Energy ; Volume 37, Issue 20 , 2012 , Pages 15423-15432 ; 03603199 (ISSN) ; Ghasemi, S ; Irajizad, A ; Akhavan, O ; Gholami, M. R ; Sharif University of Technology
Elsevier
2012
Abstract
Reduced graphene oxide (RGO) was used to improve the hydrogen sensing properties of Pd and Pt-decorated TiO2 nanoparticles by facile production routes. The TiO2 nanoparticles were synthesized by sol-gel method and coupled on GO sheets via a photoreduction process. The Pd or Pt nanoparticles were decorated on the TiO2/RGO hybrid structures by chemical reduction. X-ray photoelectron spectroscopy demonstrated that GO reduction is done by the TiO2 nanoparticles and Ti-C bonds are formed between the TiO2 and the RGO sheets as well. Gas sensing was studied with different concentrations of hydrogen ranging from 100 to 10,000 ppm at various temperatures. High sensitivity (92%) and fast response time...
Magnetic resonance tensors in uracil: calculation of 13C, 15N, 17O NMR chemical shifts, 17O and 14N electric field gradients and measurement of 13C and 15N chemical shifts
, Article Solid State Nuclear Magnetic Resonance ; Volume 37, Issue 1-2 , 2010 , Pages 13-20 ; 09262040 (ISSN) ; Shaghaghi, H ; Bain, A. D ; Chabok, A ; Tafazzoli, M ; Sharif University of Technology
2010
Abstract
The experimental 13C NMR chemical shift components of uracil in the solid state are reported for the first time (to our knowledge), as well as newer data for the 15N nuclei. These experimental values are supported by extensive calculated data of the 13C, 15N and 17O chemical shielding and 17O and 14N electric field gradient (EFG) tensors. In the crystal, uracil forms a number of strong and weak hydrogen bonds, and the effect of these on the 13C and 15N chemical shift tensors is studied. This powerful combination of the structural methods and theoretical calculations gives a very detailed view of the strong and weak hydrogen bond formation by this molecule. Good calculated results for the...
Enhanced Performance of Modified Pd/AL2O3 Catalysts by Triphenyl phosphine Ligand in Acetylene Selective Hydrogenation
, M.Sc. Thesis Sharif University of Technology ; Khorasheh, Farhad (Supervisor) ; Takht Ravanchi, Maryam (Supervisor)
Abstract
Ethylene is considered as one of the key materials in the petrochemical industry and has a particular importance. Polymerized ethylene produces polyethylene, which is widely used in plastics and pipe-manufacturing industries. Ethylene is mainly produced by the processes of catalytic cracking or thermal cracking of heavier hydrocarbon compounds. In these processes, acetylene is produced as a by-product, which deactivates the Ziegler-Nata catalysts in the polymerization unit of ethylene. Therefore, there should be some considerations to reduce acetylene to its minimum value -around zero. For this purpose, the fixed bed catalytic reactor is used to hydrogenate acetylene to ethylene. Various...
Hydrogen Production by Aqueous Phase reforming of Glycerol Over Supported Platinum Catalysts
, Ph.D. Dissertation Sharif University of Technology ; Kazemeini, Mohammad (Supervisor) ; Mohammadi, Ali Asghar (Supervisor)
Abstract
The aqueous phase reforming (APR) of glycerol is an attractive yet challenging pathway to convert abundant biomass into value added hydrogen. Pt catalysts have received attention due to their ability to produce hydrogen-rich gas under APR conditions. In this work, the conversion of glycerol into hydrogen is demonstrated using Pt0.05CexZr0.95-xO2 (x=0, 0.29, 0.475, 0.66 and 0.95) solid solution catalysts and a series of M-doped Pt-MgO (M = Pd, Ir, Re, Ru, Rh and Cr) sheet-shaped nano-catalysts. Both characteristic (XRD, BET, H2-TPR, CO-chemisorption, TEM and XPS) and reactivity measurements were used to investigate the activity of the catalysts. Results indicated that reactivity depended on...
Study On Performance Of Ic Engines Using Hydrogen As Fuel
, M.Sc. Thesis Sharif University of Technology ; Mozafari, Ali Asghar (Supervisor)
Abstract
Hydrogen is one of the favorite substitute for fossil fuels due to various properties including the flammability, ubiquity, and easy extraction from plain water. These properties have made it an appropriate alternative source of energy that can be used in internal combustion engines. Compared with fossil fuel energy, in addition to much lower emissions, hydrogen has proved to be much more efficient when applied as a clean source of energy. The main purpose of the present project is to study the effect of applying hydrogen on performance of compression - ignition as internal combustion engines as an alternative fuel. These studies encompass the results derived from the experiment of using...
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...