Find in Library

Abstract The hydrothermal reaction of water and aluminum materials was investigated as a method for hydrogen production using geothermal heat or wasted heat from industrial activities. Hydrogen was produced using pure aluminum powder at the observed temperature range of 230–340 °C and under corresponding saturated vapor pressure, and hydrogen production increased significantly with temperature. The reaction mechanism is in accordance with water reduction by aluminum, which results in the production of hydrogen and formation of boehmite (AlO(OH)) as a by-product. In an attempt to determine a more environmentally friendly hydrogen production method, the application of aluminum derived from waste, i.e., aluminum casing and aluminum foil from capacitor waste, was also examined. A similar mechanism to that with pure aluminum powder was indicated, but with a lower reaction rate due to the smaller specific surface area of the waste material. Presence of the non-aluminum materials from the capacitor waste during the reaction also has been confirmed to have no effect on the mechanism. Kinetic analysis of the reactions suggests that the reaction rate is strongly affected by the pore size and the reaction pressure. A mathematical model was developed based on kinetic analysis result to estimate the hydrogen production from water–aluminum reaction under hydrothermal conditions that can be applied to any shape of aluminum material.