The hydrogen economy has been identified as an alternative to substitute the non-sustainable fossil fuel based economy. Ongoing research is underway to develop environmentally friendly and economical hydrogen production technologies that are essential for the hydrogen economy. One of the promising ways to produce hydrogen is to use aluminum or its alloys to reduce water or hydrocarbons to hydrogen. This paper gives an overview on these aluminum-based hydrogen production methods, their limitations and challenges for commercialization. Also, a newly developed concept for cogeneration of hydrogen and electrical energy is discussed.

A review on hydrogen production using aluminum and aluminum alloys

Synthesis of nanoparticles by microorganisms and their application in enhancing microbiological reaction rates

Metal-based nanoenergetic materials: Synthesis, properties, and applications

Nano aluminum particles have received considerable attention in the combustion community; their physicochemical properties are quite favorable as compared with those of their micron-sized counterparts. The present work provides a comprehensive review of recent advances in the field of combustion of nano aluminum particles. The effect of the Knudsen number on heat and mass transfer properties of particles is first examined. Deficiencies of the currently available continuum models for combustion of nano aluminum particles are highlighted. Key physicochemical processes of particle combustion are identified and their respective time scales are compared to determine the combustion mechanisms for different particle sizes and pressures. Experimental data from several sources are gathered to elucidate the effect of the particle size on the flame temperature of aluminum particles. The flame structure and the combustion modes of aluminum particles are examined for wide ranges of pressures, particle sizes, and oxidizers. Key mechanisms that dictate the combustion behaviors are discussed. Measured burning times of nano aluminum particles are surveyed. The effects of the pressure, temperature, particle size, and type and concentration of the oxidizer on the burning time are discussed. A new correlation for the burning time of nano aluminum particles is established. Major outstanding issues to be addressed in the future work are identified.

https://www.yang.gatech.edu/publications/Journal/FGV%20(2015,%20Sundaram).pdf

Combustion of Nano Aluminum Particles (Review)

Aluminum is examined as energy storage and carrier. To provide the correct feasibility study the work includes the analysis of aluminum production process: from ore to metal. During this analysis the material and energy balances are considered. Total efficiency of aluminum-based energy storage is evaluated. Aluminum based energy generation technologies are reviewed. Technologies are categorized by aluminum oxidation method. Particularly, the work focuses on direct electrochemical (anodic) oxidation of aluminum, aluminum–water reaction in alkaline solution, mechanochemical activation of aluminum, mechanical activation of aluminum and high-temperature aluminum–water reaction. The objective is methods overview including technological principle, efficiency, urgent problems and possible application areas.

Aluminum as energy carrier: Feasibility analysis and current technologies overview

The combustion of mixtures of an ultrafine electroexplosive aluminum powder with water thickened by a 3% polyacrylamide additive is investigated. The reaction in a combustion regime is accompanied by the formation of a superheated foamy layer in gel-like water. The incompleteness of aluminum burnout in a stoichiometric mixture, which is explained by boiling-out of water from the reaction zone, is shown. The maximum combustion temperatures are determined in various conditions by means of thermocouple measurements and combustion-product composition calculations. The possibility of producing ultrafine or monolithic corundum as a reaction product is shown.

Specific features of the reaction between ultrafine aluminum and water in a combustion regime

Combustion of mixtures of ultradisperse aluminum and gel-like water

The processes of oxidation of electroexplosive ultradisperse powders (UDP) of aluminum by water in the range of temperatures 50—75°C are studied by the method of continuous recording of gas release. It is shown that the electroexplosive UDP of aluminum are capable to be actively oxidized by water with the formation of oxide—hydroxide phases and hydrogen release already upon moderate heating. At temperatures higher than 75°C the oxidation occurs like a degenerate thermal explosion. The macrokinetic parameters of the oxidation of aluminum UDP are determined. The data obtained can be used to assess the fire hazard of UDP in the presence of moisture and analyze the combustion of aluminum UDP in the composition of energy materials.

Macrokinetics of Oxidation of Ultradisperse Aluminum by Water in the Liquid Phase

The kinetic features of oxidation of ultradisperse powders of aluminum, copper, iron, molybdenum, zinc, and tin, which were obtained by the method of electric explosion of conductors, are studied by the nonisothermal thermogravimetric method. It is shown that the process of oxidation has a multistage character; however, at the initial stage, the products do not form a continuous film and the oxidation of all the metals occurs by a linear law. The temperatures of onset of oxidation with a noticeable rate are determined by the temperatures of desorption of the gas components of ultradisperse powers. The self-ignition temperatures of the powders are determined by the method of differential thermographic analysis. In addition, it is shown that these temperatures depend on the thermophysical properties of a metal and the kinetics of the initial stage of oxidation.

V. G. Ivanov

Papers

Specific features of the reaction between ultrafine aluminum and water in a combustion regime

Combustion of mixtures of ultradisperse aluminum and gel-like water

Macrokinetics of Oxidation of Ultradisperse Aluminum by Water in the Liquid Phase

Specific features of the oxidation and self-ignition of electroexplosive ultradisperse metal powders in air