Reaction Mechanism And Experimental Study Of Hydrogen Generation From Aluminum-Water

Hydrogen, an important secondary energy, can be used to store energy, which is resource-rich, environmental friendly, with a high calorific value, good combustion performance and high potential economic benefit. The application extension of hydrogen energy is limited primarily by the hydrogen production, storage methods and means of transportation. At present the existing production methods in industries are mainly from fossil fuel and electrolysis of water, which consume a lot of energy and pollute the environment with low efficiency. In this study, the hydrogen is produced from aluminum-water reaction, not only can realize on-site hydrogen production and supply, but reduce the costs of hydrogen production by adding different mineral catalytics.Aluminum is a very promising energy carrier, with abundant resources, high energy density, low prices and so on. However, aluminum can be easily passivated at room temperature, the surface of which generates a dense protective film then prevents the aluminum-water reaction. The paper is divided into three parts focusing on the destruction of the dense oxide film. The first part examines the effects of addition of NaOH, the adding ways and ratios of mineral additives (CaO, MgO, NaCl) and different reaction temperature on the hydrogen generation properties from aluminum-water, and explore the reaction mechanism by gas chromatography, SEM-EDS and XRD, the second part’s experiments are spreading in the waste water by using high calcium fly ash instead of mineral additives on the basis of previous experiments, optimizing the experimental ratio, the third part established a dynamic model of hydrogen production from aluminum-water.The results show that:NaOH is involved in the reaction process as a catalyst, an increase of NaOH concentration causes a raise of hydrogen production rate and yield, and a lot of heat generates during the process. Different intermediates generated by mineral additives CaO and MgO damage oxide film to keep the reaction. The addition of NaCl enhances the alkaline environment and improves the conversion rate. The reaction temperature has no effect on the conversion rate, but accelerated the reaction rate. Hydrogen purity of each experiment is up to 99.9%, which can generate electricity directly by hydrogen fuel cells. The nascent hydrogen during the reaction can be used to treat the waste water, and the reaction residue can be recycled for resource utilization by some easy processing.