Experimental investigation of the catalyst-free reaction characteristics of micron aluminum powder with water at low and medium temperatures

Abstract

Aluminum metal has a high energy density and can react with water to produce hydrogen instantly, which is environmental-friendly and safe. Aluminum has great potential to provide a good carrier for energy and hydrogen storage. The utilization of aluminum is constrained by the oxide layer on its surface. In order to promote the aluminum-water reaction to continue efficiently, the reaction needs to be activated. The modification of aluminum is often complicated and dangerous, and it is difficult to apply the hydrogen produced by the reaction and the heat released. The increase of temperature and pressure of the reaction has also been proved as a useful activation method. Continuous reactions are difficult to achieve at high temperature and pressure, and it becomes difficult to obtain reaction initiation and development processes. However, the reaction process has an essential impact on the utilization of the aluminum-water reaction. In this paper, the aluminum-water reaction process at medium temperature was investigated using micron aluminum powder. The effects of initial temperature, particle size of aluminum powder and water type on the reaction were further analyzed. In addition, the kinetic analysis of the aluminum-water reaction was carried out to obtain kinetic models. Experimental results indicate that the product of the aluminum-water reaction is Al(OH)3 at 90–150 °C. The reaction initial temperature shows a multipolar effect on the reaction between aluminum and water. The hydrogen yield from the reaction between ∼25 μm aluminum powder and tap water at 150 °C is 31.9 %. The pre-exponential factor and apparent activation energy increase with the reaction proceeding. The present research is conducive to further safe and efficient utilization of micron aluminum powder for energy conversion, and benefits the achievement of carbon peaking and carbon neutrality.