Experimental study on characteristics and mechanism of hydrogen production from aluminium–water reaction for carbon-free power generation

• Published in: Fuel (Guildford) Vol. 380; p. 133206
• Main Authors: Gao, Xinyue, Wang, Chang’an, Hou, Yujie, Zhao, Lin, Bai, Wengang, Che, Defu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.01.2025
• Subjects: Aluminum–water reaction; Carbon-free power generation; Energy storage; Hydrogen production; Reaction mechanism; Supercritical water; Reaction mechanism; Carbon-free power generation; Aluminum–water reaction; Supercritical water; Hydrogen production; Energy storage
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.133206

•The reactivity of supercritical water prevents passivation layers, aiding reaction.•Al undergoes an extra adsorption phase with gaseous water compared to liquid.•Al reacts slower with gaseous than liquid H2O, even in supercritical conditions.•Prolonging reaction duration, and lowering heating rate enhances Al-H2O conversion.•Al acts as a renewable fuel, yielding heat and H2 for zero-carbon power. The potential of hydrogen production and power generation via aluminum–water reactions has been limited by the inhibition phenomenon within the oxide layer. While raising the temperature effectively mitigates this issue, sustaining liquid water state requires high pressure, an underexplored factor. Furthermore, the underlying mechanisms behind these processes remain unclear. This study investigates disparities in hydrogen production characteristics and mechanisms between aluminum–gas water reactions and aluminum–liquid water reactions within the temperature range of 250–376 °C and pressures ranging from 4.0–23.5 MPa. The effects of reaction temperature, pressure, supercritical water, duration, and heating rate on hydrogen yield, solid products, and reaction mechanisms for millimeter-sized aluminum particles were investigated and a new carbon-free power generation system was proposed. The 1–4 mm aluminum particles achieve 100 % hydrogen yield at 350–360 °C and 16.5–18.7 MPa. The supercritical water demonstrates strong reactivity, inhibiting passivation, with 8 mm aluminum particles fully oxidized at 376 °C and 23.5 MPa. Hydrogen yield from gaseous water reactions is slightly lower or equal to that from liquid water reactions due to the differences in mechanisms and aluminum surface contact opportunities. The proposed zero-carbon power generation system demonstrates the potential of aluminum for continuous energy storage and large-scale power generation, contributing to a clean and safe energy storage system.