Optimization of aluminum hydrolysis reactions and reactor design for continuous hydrogen production using aluminum wire feeding

Abstract

The depletion of fossil fuels and the issues caused by CO2 emissions are driving changes in global energy approaches. In this context, hydrogen emerges as a new and clean energy carrier for the near future. In this study, a system that can produce hydrogen with a constant flow rate for on-demand applications is developed. Hydrolysis reactions of aluminum are utilized for hydrogen generation. Aluminum in the form of wire is used and the feeding issues have been solved. The parameters of the hydrolysis such as the solution temperature (25–80 °C), catalyzer concentration (1–4 M NaOH), aluminum quantity and aluminum wire diameter (0.6–1 mm) were optimized by adopting the response method (RSM) and using laboratory scale experiments. Aluminum hydrolysis reactions and aluminum transformations during the reactions are investigated by performing surface analyzes of the wire. Using the optimized data, the continuous hydrolysis reactor and the aluminum feeding mechanism are designed. The aluminum wire feeding system is computer controlled using a microcontroller-based code. Hydrogen production rates up to 350 ml min−1 have been accomplished. A fuel-cell in the range of 5–30 W is fed by the hydrogen generated by the hydrolysis reactor system and the stability of the hydrogen generation rate and hence of the electricity generation is proven. One of the original aspects of this study is the development of a process that continuously produces hydrogen using commercially available aluminum.