Investigation of High-Temperature Metal-Water Reactions for Sustainable Hydrogen Production
2016
DOI: https://escholarship.mcgill.ca/concern/papers/t722hc603?locale=en
Jiayi Wang
Abstract
An experimental method was developed to study metal-water reaction at high temperature and high pressure. This work includes the completion and testing of an experimental method and apparatus that allows for the separate preheating and fast mixing of metal powder and liquid water during a reaction. The metal powder and water are initially separated by a diaphragm. The reaction occurs when the increased vapor pressure of water causes the diaphragm to break. Diaphragms of different materials and thicknesses were tested. Experiments were conducted using aluminum and silicon as the metal powder in the reaction. The experimental method and apparatus were tested at reaction temperatures of 165 °C to 260 °C. The silicon powder did not show any indication of reaction with water in this temperature range. The aluminum powder consistently reacted with water in the same temperature range.
The use of supercritical water to enable the catalyst-free oxidation of coarse aluminum for hydrogen production
August 2020
Keena Trowell, Sam Goroshin, David Frost, Jeffrey Bergthorson
Abstract
Maximizing the use of renewable resources requires clean, sustainable and recyclable energy carriers for energy trade and long-term storage. Aluminum is energy dense, plentiful, recyclable and, when reacted with water, the stored energy is released as hydrogen and heat. In this study, we investigated the use of high-temperature liquid water and supercritical water as oxidizers for coarse aluminum. We performed experiments using a variety of aluminum morphologies, including coarse aluminum pieces measuring up to 3 mm in diameter, and water ranging in temperature from 475 K to 650 K (and the corresponding saturated vapour pressures). Previous studies of aluminum-water reactions have focused on low temperature experiments using catalysts, specialized alloys, or nano-powders to increase reaction efficiency. These low-temperature approaches can be effective but add complexity, expense and waste the thermal energy of the reaction. Our results show that, without special measures, 100 % hydrogen yield is possible from coarse aluminum particles, and scrap aluminum, when reaction temperature and pressure are increased. A change in reaction efficiency was observed at 550K. Up to this temperature, the 55μm and 120 μm had yields below 30 % and the aluminum slugs and 2 mm plate had a yields close to zero. At temperatures between 550 K and the supercritical temperature, there was a marked increase in hydrogen yield. At temperatures above 647 K and pressures above 220 bar, the critical point of water, 100 % of the theoretical hydrogen yield was achieved across all samples tested. These findings open the door to using aluminum as a recyclable energy carrier for renewable energy.
Aluminum-Water Reactions for Hydrogen Production: An investigation of its implementation in power generation devices
July 2022
Link: https://escholarship.mcgill.ca/concern/papers/z603r355s?locale=en
Jenny Kim, Jeffrey Bergthorson
Abstract
An analytical investigation of a novel alternative fuel source, aluminum powder, for its reactive properties upon reaction with water. Extensive research has been performed over the years studying metal-water reactions for their heat generation and in-situ hydrogen production. Both theoretical and experimental studies have focused on determining the effect of parameters such as the type of metal, metal-to-water ratio, activation method, particle size, and temperature of the reaction. However, few have explored the implementation of such fuel in a power generation device. This work explores the use of aluminum-water reactions to power three different Siemens engines of varying power outputs: two industrial engines- RB211 (33 MW) and Trent 60 (66 MW) and one heavy duty gas turbine- SGT5-4000F (329 MW). The thermodynamics cycle is proposed, and analysis is performed to determine the required reactor size. Then, a life cycle carbon emission of aluminum-water fuel is analyzed and evaluated against that of natural gas – the fuel currently used in the three engines.
Hydrogen production rates of aluminum reacting with varying densities of supercritical water
April 2022
DOI: https://pubs.rsc.org/en/content/articlelanding/2022/RA/D2RA01231F
Keena Trowell, Sam Goroshin, David Frost, Jeffrey Bergthorson
Abstract
Aluminum particles, spanning in size from 10 μm to 3 mm, were reacted with varying densities of water at 655 K. The density of the water is varied from 50 g L−1 to 450 g L−1 in order to understand the effect of density on both reaction rates and yields. Low-density supercritical water is associated with properties that make it an efficient oxidizer: low viscosity, high diffusion, and low relative permittivity. Despite this, it was found that the high-density (450 g L−1) supercritical water was the most efficient oxidizer both in terms of reaction rate and hydrogen yield. The 10 μm powder had a peak reaction rate of approximately 675 cmH23 min−1 gAl−1 in the high-density water, and a peak reaction rate below 250 cmH23 min−1 gAl−1 in the low- and vapour-density water. A decline in peak reaction rate with decreasing water density was also observed for the 120 μm powder and the 3 mm slugs. These findings imply that the increased collision frequency, a property of the high-density water, outpaces reduction in the reaction enhancing properties associated with low-density supercritical water. Hydrogen yield was minimally affected by decreasing the oxidizer density from 450 g L−1 to 200 g L−1, but did drop off significantly in the vapour-density (50 g L−1) water.
Comparative reactivity of industrial metal powders with water for hydrogen production
December 2014
Yinon Yavor, Sam Goroshin, Jeffrey M. Bergthorson, David L. Frost
Abstract
The in-situ production of hydrogen from a metal-water reaction resolves some of the main obstacles related to the use of hydrogen as an alternative fuel, namely storage and safety. In this study, experiments are conducted in a batch reactor with sixteen different commercially-available industrial metal powders, with water temperatures ranging from 80 to 200 _C. The hydrogen production rate, total yield, and reaction completeness are determined for each metal-powder fuel and reaction temperature. Aluminum powder produces the largest amount of hydrogen per unit mass throughout the temperature range, followed by the magnesium powder. Manganese powder, which produces the largest amount of hydrogen per unit volume at high temperatures, exhibits a sharp increase in yield between 120 and 150 _C, suggesting the existence of a critical energetic threshold. The aluminum and magnesium powders exhibit high reaction rates, and together with the manganese powder, appear to be the most attractive candidates to serve as fuels for in-situ hydrogen production.