Optimizing the production procedure of ball milled Magnesium-Nickel powders for hydrogen storage applications
Date
2017-10-11
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0002-0937-0222
Type
Thesis
Degree Level
Masters
Abstract
With the advent of time and growing world population, the demand of energy is rising everyday exponentially. Developing renewable sources is important in fulfilling a part of our present energy demands. However, at present, a very significant part of energy is derived from the fossil fuels. Using fossil fuels as the main source of energy has some serious drawbacks.
Fossil fuels are present in the earth’s crust in a limited amount and will be exhausted at some point of time. Also, burning fossil fuels to produce energy is responsible for the rising levels of carbon dioxide in the earth’s atmosphere. This has led to environmental issues such as the global warming.
Hydrogen is a potential alternative to fossil fuels due to its high calorific value and cleaner combustion. The major issue in using hydrogen as a fuel is its storage. Amongst different materials, magnesium is the most suitable candidate for storing hydrogen due to its high theoretical hydrogen storage estimated value (7.5wt%) and economical cost.
Magnesium however has slow reaction kinetics therefore various methods have been investigated to improve its hydrogen storage capacity and reaction kinetics.
In this thesis the effect of different parameters (ball milling time, nickel percentage, hydrogen charging pressure and hydrogen charging temperature) in the production of Magnesium-Nickel powders for the storage of hydrogen were studied. The phase distribution, particle size and morphology were also determined by using scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. It was established that Mg-10%Ni ball milled for 10hours, charged at a hydrogen pressure and temperature of 20 bar and at 300 °C respectively was the best sample in terms of the amount of hydrogen stored (≈ 5.6 weight percent) and the hydrogen discharge rate. Cross-sectional SEM and EDS scans revealed that upon ball milling for 10 hours the internal structure of the particles became layered, hosting numerous potential sites for the hydrogen atom residence. It was also clear that the distribution of nickel over magnesium particles was uniform when ball milled for 10 hours.
Description
Keywords
Hydrogen storage
Citation
Degree
Master of Science (M.Sc.)
Department
Mechanical Engineering
Program
Mechanical Engineering