Maximized on-demand hydrogen generator design

In this paper, magnesium hydride was used to react with water using a new design of control strategy to produce maximized on-demand hydrogen generation from the hydrolysis reaction. Magnesium hydride is the chemical compound MgH₂, which contains 7.66% by weight of hydrogen and as a potential hydrogen source. Although the concept of reacting chemical hydride with water to produce hydrogen is not new, there have been a number of recent published papers which might be employed as on site generation of hydrogen for fuel cell applications. Under room temperature, the hydrolytic reaction between magnesium hydride and water to form a thin-layer of magnesium hydroxide on the outer surface impedes water from coming into direct contact with the magnesium hydride. The key to continual removal of this coherent magnesium hydroxide layer can induce the reaction of magnesium hydride with water near room temperature by the addition of citric acids. These additions act to disrupt the magnesium hydroxide layer on the magnesium hydride. This concept of using the magnesium hydride reaction with water to produce hydrogen has the following conclusions. This study presents a maximized on-demand hydrogen gas generator capable of producing hydrogen at an almost-constant H₂ rate, which using this approach can reach the 6.4% by weight of hydrogen. In addition, based on the kinetics of magnesium hydride-water reaction, it does not need any noble-metals catalysts to meet the minimum hydrogen flow rate for fuel cell power systems. Finally, the cost of producing hydrogen from magnesium hydride-water approach would cost approximately $15 per kg hydrogen.