HYDROGEN GENERATION BY REACTION OF BALL-MILLED MAGNESIUM POWDER WITH HOT WATER

Abstract

Hydrogen is a very promising source of fuel; it has already constituted a significant part of modern innovations for power generation in automobile and space shuttle. Hydrogen can be produced from several sources and as a byproduct of some chemical processes, including the association of magnesium with water. The production yield of this later production method is limited by influences associated with the formation of passive oxide/hydroxide films on the surface of magnesium metal during reaction. The experiments within this project highlight optimization conditions towards improved hydrogen yield via magnesium hydrolysis. Reduced rate of hydroxide layer formation on Mg surface, hence increased production yield, is accomplished by exposing a greater surface area of Mg in contact with water. This has been achieved via ball milling process; Mg powders with greater higher surface area to volume ratios are ball-milled with certain salts (e.g. NaCl and KCl). The weight percentage (wt.%) of these salt within the mixture influences hydrogen production yield by facilitating the creation of reaction sites. Here, these salts produce cavities within the magnesium/salt powdery matrices, thus creating more assessable surface area for water. The experimental results from this work reveal that ball milling duration and weight percentage of salts affect the final size of Mg particle produced. Thus, the maximum hydrogen yield is achieved by controlling these two parameters and the results are further correlated by the microstructure of the samples under scanning electron microscope (SEM).