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hydrogen-storage
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Preparation of Hydrogen Adsorbent Nanoporous Polymer for Fuel Cell Applications
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor) ; Mousavi, Abbas (Supervisor)
Abstract
Application of fuel cells as one of the new and clean energy generators at recent years is many interesting for governments. In many cases hydrogen gas is fuel of these cells. One of the problems at this field is issue of hydrogen storage with a safety and ecconemical way. Usually storage of hydrogen be done with several different ways : Composite tank, Liquid hydrogen, Metal hydride , Chemical hydride, carbon nanotube and etc. Use of polymers that have ability of adsorption is one of topics that is attended at these years , because of their low density and easy process ability and low explosion risk and economical aspect . So at this research we try to identify polymers that have...
Effect of Selected Promotors on the Electrocatalytic Performance in Oxygen Evolution Reaction
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Cyrus (Supervisor) ; Larimi, Afsaneh Sadat (Supervisor)
Abstract
During the last few decades, efforts have been made to replace fossil fuels with clean and non-absorbent energy sources. One of the promising strategies is energy production by hydrogen storage using water splitting. For this purpose, different methods of using light, heat and electricity are provided. Electrolysis of water with a simple environment such as very high purity of hydrogen produced, controllable, device, no need for high temperature and pressure in the reactor and huge potential for industrial applications has been very much considered. Water electrolysis consists of two reactions: reduction of water to hydrogen (HER) and oxidation of water to oxygen (OER). The second reaction...
Production of Magnesium Nanoparticles by Electromagnetinc Levitation Melting
, M.Sc. Thesis Sharif University of Technology ; Halali, Mohammad (Supervisor)
Abstract
Electromagnetic levitation(EML) provides a process producing nanoparticles using gas condensation method. In gas condensation processes, vapor is produced by heating the sample then inert gas is applied to provide the inert atmosphere and also cool and condense the sample vapor into a nano powder to obtain a sample nanoparticle. In the EML method, rapidly alternating electromagnetic field induces eddy current in the conducting sample which will heat the sample. The current in the sample result in an induced magnetic field. Consequently, the sample droplet is heated and levitated simultaneously by an induction furnace as a generator. The sample temperature is dependent on parameters such as...
Performance of a standalone wind-hydrogen power system for regions with seasonal wind profile: A case study in Khaf region
, Article Sustainable Energy Technologies and Assessments ; Vol. 7 , September , 2014 , pp. 265-278 ; ISSN: 22131388 ; Rezaei Mirghaed, M ; Roshandel, R ; Sharif University of Technology
Abstract
The present study was aimed at performance and energy analysis of a hybrid wind-hydrogen power system. Such system consists of wind turbines, batteries for the short time energy storage, electrolyzer, fuel cell and hydrogen tank for long time energy storage. The proposed configuration is used to supply energy demand of a region with discrete seasonal wind speed regime. Temporary wind energy profiles restrict using batteries for electricity storage as they lose much electrical stored energy for the long time. Based on direct wind turbine usage, batteries and hydrogen storage, different energy supply strategies are introduced and analyzed to power the household electricity demand. The energy...
Structural characteristics and desorption properties of nanostructured MgH2 synthesised by high energy mechanical milling
, Article Powder Metallurgy ; Volume 54, Issue 4 , 2011 , Pages 480-483 ; 00325899 (ISSN) ; Kaflou, A ; Simchi, A ; Sharif University of Technology
2011
Abstract
The effect of particle size, lattice strain and crystallite size on the hydrogen desorption properties of nanocrystalline magnesium hydride powder was investigated. Commercial MgH2 powder was milled in a Spex 8000M up to 16 h and its structural evolution and desorption characteristics at different time intervals were examined using various analytical techniques. At the early stage of milling, the formation of metastable γ-MgH2 phase was noticed. While the crystallite size gradually decreased to 12 nm with increasing the milling time, the accumulated lattice strain gained a maximum value of 0·9% after 4 h milling. The highest drop in the desorption temperature (∼100°C) was attained at the...
Selective storage and evolution of hydrogen on nafion/NaCl/graphene quantum dot mixed matrix using tensammetry as power electrochemical technique
, Article International Journal of Hydrogen Energy ; Volume 42, Issue 15 , 2017 , Pages 9428-9439 ; 03603199 (ISSN) ; Zakipour, M ; Doroodmand, M. M ; Mehrtash, M ; Sharif University of Technology
Abstract
Hydrogen storage/evolution behavior of nafion/NaCl/graphene quantum dot (GQD) mixed matrix as selective hydrogen capacitor (power source) was evaluated in detail through an electrochemical process at two independent potential ranges. For this purpose, a three-electrode system included Pt disk as counter electrode, Ag/AgCl as reference electrode and GQD-based mixed matrix-modified Pt disk as working electrode. For hydrogen storage, the deposition potential and time were evaluated to −1.0 V (vs. Ag/AgCl) and 120 s, respectively under high basic solution generated using NaOH (1.0 M) solution, followed by evolution of hydrogen at +0.8 V (vs. Ag/AgCl) during formation of hydrogen bubbles. The...
Desorption properties of nanostructured MgH2 synthesized by high-energy mechanical milling
, Article European International Powder Metallurgy Congress and Exhibition, Euro PM 2008, Mannheim, 29 September 2008 through 1 October 2008 ; Volume 2 , 2008 , Pages 351-356 ; 9781899072033 (ISBN) ; Simchi, A ; Kaflou, A ; Sharif University of Technology
European Powder Metallurgy Association (EPMA)
2008
Abstract
The hydrogen desorption properties of nanocrystalline magnesium hydride processed by high-energy mechanical milling was investigated. MgH2 powder was milled for various times (up to 16 h) under a high purity argon atmosphere and the effect of milling on the particle size and morphology, grain refinement, lattice strain, and desorption temperature was studied. It was shown that accumulated lattice strain combined with nanometric grain structure significantly decrease the desorption temperature. The effect of powder particle size was found to be of less importance. The lowest desorption temperature was obtained after 4 h high-energy milling. Nanostructured magnesium hydride with grain size of...
Investigation on Parameters of Carbon Nanotubes Growth and Effect of Interaction between H2 Gas and their Surfaces and Determining Capacity of Hydrogen Storage
, Ph.D. Dissertation Sharif University of Technology ; Moshfegh, Alireza (Supervisor) ; Nozad, Ahmad (Supervisor)
Abstract
In this study, growth of MWCNTs in form of thin film and powder for hydrogen storage was investigated. Different analytical techniques including SEM, TEM, STA, XRD, XPS, BET, BJH and Raman spectroscopy were applied to characterize the samples. The results showed that substrate, catalyst thickness and type of catalyst are influenced in yield of the growth, structure and quality of MWCNTs. The study has also indicated that MWCNTs grown on Fe-Pd bimetallic catalyst with 25-75 proportion had the highest growth yield. Moreover, decreasing of the growth temperature from 970 to 920 oC produced single-walled carbon nanotubes (SWCNTs) with high quality (IG/ID = 15.8) and low growth yield....
The Experimental Study of Adsorption and Separation of Hydrogen Gas Using Metal-organic Frameworks
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Cyrus (Supervisor) ; Karimi Sabet, Javad (Supervisor)
Abstract
Hydrogen gas is considered as a clean fuel and energy carrier that its storage for future uses is a challenging issue. One of the methods to store it, is adsorption on a group of adsorbents called metal-organic frameworks. In this research, one of these frameworks called ZIF-8, has been selected to study hydrogen storage capability. To evaluate the effect of having two metals, a mixture of two metals was used in the synthesis process. To characterize the structure of the synthesized adsorbents, X-ray powder diffraction (XRD),adsorption and desorption of nitrogen at temperature of 77 K, Field Emission Scanning Electron Microscopy (FESEM), energy-dispersive X-ray Spectroscopy (EDS) and...
Assessment of 3-Dimensional Structure of Graphene Nanostructures for Increasing Hydrogen Storage Capacity
, M.Sc. Thesis Sharif University of Technology ; Saboohi, Yadollah (Supervisor)
Abstract
In this dissertation, Hydrogen storage in the solids based was investigated. The carbon-based structure used is the graphene that decorated with metal atoms to increase intermolecular interactions and increase the adsorption weight capacity. The structure of graphene has been considered due to its properties such as low density, high heat transfer coefficient and high specific surface area. Initially, the structure of pure graphene was investigated using the molecular dynamics method for hydrogen storage and it was shown that the interaction between hydrogen molecules and pure graphene is very weak and it can’t be a good option for use in cars. Then, the structures of graphene reinforced...
Microfluidic Investigation of Hydrogen-Water Flow at Pore-Scale for Subsurface Hydrogen Storage
, M.Sc. Thesis Sharif University of Technology ; Mahani, Hassan (Supervisor) ; Ayatollahi, Shahaboddin (Supervisor) ; Zivar, Davood (Co-Supervisor)
Abstract
Hydrogen storage in porous subsurface formations, such as aquifers or depleted hydrocarbon reservoirs because of their high storage capacity, has gained momentum as a promising approach to balance the renewable energy supply and demand. However, the poor understanding of hydrogen flow dynamics in porous media is the main obstacle to the development and widespread application of underground hydrogen storage (UHS). For example, the main uncertainty is lack of detailed understanding of hydrogen flow dynamics in the natural porous media which leads to the unknown volume of recoverable hydrogen for this cyclic process. In this research, by developing a visual microfluidic apparatus to handle...
Cyclic Simulation of Field-Scale Underground Hydrogen Storage
, M.Sc. Thesis Sharif University of Technology ; Mahani, Hassan (Supervisor) ; Zivar, Davood (Co-Supervisor)
Abstract
Due to environmental concerns about fossil fuels energy sources, countries are striving to replace fossil fuels with renewable energy sources. However, most alternative energy sources are highly dependent on weather and seasonal conditions. Underground hydrogen storage (UHS), unlike carbon dioxide storage which only experiences the gas injection phase, involves injection and production cycles. Therefore, it faces different challenges, each of which has different effects on the final hydrogen recovery rate and, consequently, cost estimation. Some of the major challenges ahead include the reservoir structure, heterogeneity of reservoirs, selection of suitable cushion gas, the impact of the...
Molecular Dynamics Simulation of Hydrogen Diffusion into Brine: Implications for Underground Hydrogen Storage
, M.Sc. Thesis Sharif University of Technology ; Ayatollahi, Shahaboddin (Supervisor) ; Mahani, Hassan (Supervisor) ; Pourkhiabani, Nahid (Co-Supervisor) ; Esmaeilbeig, Mohammad Amin (Co-Supervisor)
Abstract
The high consumption of worldwide fossil energy and its detrimental effects on the environment and climate have prompted a transition toward renewable energy sources. The availability of renewable energy sources depends on weather and seasonal changes; therefore, an imbalance between supply and demand would be unavoidable. Hydrogen storage as an energy carrier, can fulfill this energy mismatch. Storing hydrogen in underground formations, such as aquifers, has been the subject of extensive research recently. In these storage reservoirs, hydrogen contacts the resident brine which will be lost through the dissolution-diffusion mechanism. Therefore, successful design of these storages requires...
A comparative study on hydrogen interaction with defective graphene structures doped by transition metals
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Vol. 60 , June , 2014 , pp. 104-111 ; ISSN: 13869477 ; Saboohi, Y ; Sharif University of Technology
Abstract
In the present work, the interaction of hydrogen molecules with defective graphene structures doped by transition metal (TM) atoms is investigated by using first principles density functional theory (DFT). Defective graphene structures include Stone-Wales (SW), 585 and 555-777 and transition metals include early TMs, i.e. scandium (Sc), titanium (Ti) and vanadium (V). It is found that in comparison with the pristine graphene, presence of defects significantly enhances the metal binding. Among three defects, 585 divacancy leads to the strongest binding between graphene and metal. Hydrogen adsorption is then evaluated by sequential addition of hydrogen molecules to the system. The results...
Evolutionary optimization approaches for direct coupling photovoltaic-electrolyzer systems
, Article IEOM 2015 - 5th International Conference on Industrial Engineering and Operations Management, Proceeding, 3 March 2015 through 5 March 2015 ; 2015 ; 9781479960651 (ISBN) ; Maroufmashat, A ; Al-Adwani, S ; Khavas, S. S ; Elkamel, A ; Fowler, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Hydrogen is an important storage medium and can be produced by the water electrolysis. In this research, energy transfer loss between a photovoltaic (PV) unit and electrolyzer is minimized by optimizing the size and operating condition of an electrolyzer directly connected to a PV module. In directly coupled photovoltaic-electrolyzer (PV/EL) systems, there is a mismatch between output PV's maximum power point characteristic and input PEM electrolyzer's characteristic. With proper sizing optimization methods, it is possible to directly couple photovoltaic-electrolyzer systems. The evolutionary optimization algorithms like genetic algorithm (GA), particle swarm optimization (PSO) and...
A model for investigation of optimal hydrogen pathway, and evaluation of environmental impacts of hydrogen supply system
, Article International Journal of Hydrogen Energy ; Volume 33, Issue 24 , 2008 , Pages 7314-7325 ; 03603199 (ISSN) ; Saboohi, Y ; Shayegan, J ; Sharif University of Technology
Elsevier Ltd
2008
Abstract
In order to achieve a hydrogen economy, developing widespread hydrogen supply systems are vitally important. A large number of technological options exist and are still in development for hydrogen production, storage, distribution., which cause various pathways for supplying hydrogen. Besides the technical factors, there are other effective parameters such as cost, operability, reliability, environmental impacts, safety and social implications that should be considered when assessing the different pathways as optimal and viable long-term alternatives. To aid this decision-making process, we have developed a generic optimization-based model for the long-range energy planning and design of...
Hydrogen desorption properties of MgH2-TiCr1.2Fe 0.6 nanocomposite prepared by high-energy mechanical alloying
, Article Journal of Power Sources ; Volume 196, Issue 10 , 2011 , Pages 4604-4608 ; 03787753 (ISSN) ; Kaflou, A ; Simchi, A ; Sharif University of Technology
Abstract
In the present work, high-energy mechanical alloying (MA) was employed to synthesize a nanostructured magnesium-based composite for hydrogen storage. The preparation of the composite material with composition of MgH2-5 at% (TiCr1.2Fe0.6) was performed by co-milling of commercial available MgH2 powder with the body-centered cubic (bcc) alloy either in the form of Ti-Cr-Fe powder mixture with the proper mass fraction (sample A) or prealloyed TiCr1.2Fe0.6 powder (sample B). The prealloyed powder with an average crystallite size of 14 nm and particle size of 384 nm was prepared by the mechanical alloying process. It is shown that the addition of the Ti-based bcc alloy to magnesium hydride yields...
Direct Numerical Simulation of Hydrogen-Water Flow at Pore-Scale During Underground Hydrogen Storage using Computational Fluid Dynamic Methods
, M.Sc. Thesis Sharif University of Technology ; Mahani, Hassan (Supervisor) ; Ayatollahi, Shahabedin (Supervisor) ; Zivar, Davoud (Co-Supervisor)
Abstract
Mass or large-scale storage of hydrogen, as a clean source of energy, should be conducted in underground formations in order to be used as a reliable energy source at the peak of consumption. In this regard, underground formations such as aquifers and depleted hydrocarbon reservoirs are the most favorable and secured media for hydrogen storage. However, detailed understanding of the flow dynamics of hydrogen-water in these media is critical to maximize hydrogen storage and recovery and tackle the existing uncertainities which exist in the flow functions. To fill this gap, this research aims at a detailed pore-scale investigation of the effect of flow regime, hydrogen compressibility, and...
Effects of Ti-based catalysts on hydrogen desorption kinetics of nanostructured magnesium hydride
, Article International Journal of Hydrogen Energy ; Volume 39, Issue 36 , December , 2014 , Pages 21007–21014 ; ISSN: 03603199 ; Simchi, A ; Sadati, M ; Hosseini, H. M ; Targholizadeh, H ; Khakbiz, M ; Sharif University of Technology
Abstract
In the present work, the synergetic effect of Ti-based catalysts (TiH2 and TiO2 particles) on hydrogen desorption kinetics of nanostructured magnesium hydride was investigated. Nanostructured 84mol% MgH2-10%mol TiH2-6%mol TiO2 nanocomposite powder was prepared by high-energy ball milling and subjected to thermal analyses. Evaluation of the absorption/desorption properties revealed that the addition of the Ti-based catalysts significantly improved the hydrogen storage performance of MgH2. A decrease in the decomposition temperature (as high as 100°C) was attained after co-milling of MgH2 with the Ti-based catalysts. Meanwhile, solid-state chemical reactions between MgH2 and TiO2 nanoparticles...
Hydrogen generation optimization in a hybrid photovoltaic-electrolyzer using intelligent techniques
, Article ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology, FUELCELL 2012 Collocated with the ASME 2012 6th International Conference on Energy Sustainability, San Diego, CA, USA, 23 July 2012 through 26 July 2012 ; July , 2012 , Pages 19-24 ; 9780791844823 (ISBN) ; Seyyedyn, F ; Roshandel, R ; Bouroshaki, M ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2012
Abstract
Hydrogen is a flexible energy carrier and storage medium and can be generated by electrolysis of water. In this research, hydrogen generation is maximized by optimizing the optimal sizing and operating condition of an electrolyzer directly connected to a PV module. The method presented here is based on Particle swarm optimization algorithm (PSO). The hydrogen, in this study, was produced using a proton exchange membrane (PEM) electrolyzer. The required power was supplied by a photovoltaic module rated at 80 watt. In order to optimize Hydrogen generation, the cell number of the electrolyser and its activity must be 9 and 3, respectively. As a result, it is possible to closely match the...