Solid-State Combustion of Metallic Nanoparticles: New Possibilities for an Alternative Energy Carrier

Abstract

As an alternative to conventional methods of conveying and delivering energy in mobile applications or to remote locations, we have examined the combustion of nanostructured metal particles assembled into metal clusters. Clusters containing iron nanoparticles (∼50nm in diameter) were found to combust entirely in the solid state due to the high surface-to-volume ratio typical of nanoparticles. Optical temperature measurements indicated that combustion was rapid (∼500ms), and occurred at relatively low peak combustion temperatures (1000-1200K). Combustion produces a mixture of Fe(III) oxides. X-ray diffraction and gravimetric analysis indicated that combustion was nearly complete (93–95% oxidation). Oxide nanoparticles could be readily reduced at temperatures between 673K and 773K using hydrogen at 1atm pressure, and then passivated by the growth of a thin oxide layer. The nanostructuring of the particles is retained throughout the combustion–regeneration cycle. Modeling of the combustion process is in good agreement with observed combustion characteristics.

Study of Oxidation and Combustion Characteristics of Iron Nanoparticles under Idealized and Enginelike Conditions

“…It is worth noting that the estimated heat release reported in Figure 17d represents the heat exchange process between particles and cylinder gas only, while the heat loss through the wall is not 24 considered. It can be observed that particles started to burn at about 100 CA-BTDC, as the compressed gas temperature reached 500 K. This observation is in line with relevant iron nanoparticles combustion data previously reported [5]. Moreover, the peak thermodynamic gas temperature was calculated at around 1500-1600 K. Based on the curves of heat release and heat release rate, combustion of iron nanoparticles appeared to develop in two distinct phases, a behavior that has been reported in previous published work [3].…”

“…A similar study for nano-aluminum has already been published [3,4]. To the best knowledge of the authors of this manuscript, there has only been one short publication on iron as a potential ICE fuel [5], which drew some preliminary, yet encouraging conclusions. Recent work has been performed on the combustion effects of adding iron nanoparticles into n-decane or ethanol-based fuels [6] and Diesel [7].…”

Direct combustion of recyclable metal fuels for zero-carbon heat and power

“…Metals, and specifically metal powders, are a promising, yet largely-overlooked, zero-carbon recyclable-fuel option [25,[46][47][48][49][50][51][52][53][54]. Metals are the most promising zero-carbon fuel choice because they react energetically with the oxygen in air to form stable, nontoxic solid-oxide combustion or reaction products that can be collected, relatively easily, for recycling, as discussed in this paper.…”

“…The combustion of metal fuels within ICEs has been proposed by several authors [49,53,54]. Unfortunately, the properties of metal powders are not well-suited for fuelling ICEs.…”

“…Aluminum and magnesium are widely studied for use as anodes in metal-air batteries [19,22,24,25], and have been considered as recyclable fuels that carry clean energy [25,53,54,67,68]. Iron has been considered both as an inexpensive anode material [23] and a recyclable energy carrier [49,50].…”