Magnesium-manganese oxides for high temperature thermochemical energy storage

Randhir, Kelvin; King, Keith D.; Rhodes, Nathan R.; Li, Like; Hahn, David W.; Mei, Renwei; AuYeung, Nick; Klausner, James F.

doi:10.1016/j.est.2018.11.024

Cited by 53 publications

(41 citation statements)

References 47 publications

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“…Reactive stability and oxygen exchange capacities for magnesium‐manganese oxides under redox condition 1 with Mn/Mg ratios of 2/3, 1/1, and 2/1 have already been studied by Randhir et al In the current study, reactive stability and oxygen exchange capacities for samples of Mn/Mg of 3/2 and 3/1 are studied and compared with those previously studied. Materials are prepared using the solid‐state reaction method, where raw powders of the pure metal oxides are mixed according to the desired stoichiometric ratio, ball‐milled for 24 hours to ensure even mixing, heat‐treated at 1500°C under air for 20 hours, then cooled to 1000°C and heat treated for an additional 4 hours.…”

Section: Experimental Methodsmentioning

confidence: 71%

“…These two opposing effects imply the existence of an optimum Mn/Mg ratio that maximizes energy density. Prior thermodynamic calculations show increased oxygen release capacities across all Mn/Mg ratios for the same reduction temperature at low

P_{{normalO}_{2}}

, indicating that higher energy density can be achieved.…”

Section: Introductionmentioning

confidence: 91%

“…Porous reactive metal oxides are gaining significant interest for thermochemical energy storage (TCES) systems . Randhir et al have presented magnesium‐manganese oxide as a promising candidate with reactive stability at high temperatures (1000 ≤ T ≤ 1500°C) and measured energy densities of 1596, 1626, and 1654 MJ m −3 for molar ratios Mn/Mg of 2/3, 1/1, and 2/1, respectively, for a redox cycle between 1000°C and 1500°C at constant oxygen partial pressure (

P_{{normalO}_{2}}

) of 0.2 atm . The overall reversible chemical reaction utilized for energy storage is given by,

{Mg}_{x} {MnO}_{1 + x + C_{1}} \leftrightarrow {Mg}_{x} {MnO}_{1 + x + C_{2}} + \frac{C_{1} - C_{2}}{2} O_{2}

where x is the molar ratio of Mg to Mn, and C 1 and C 2 , denote the excess oxygen within the material lattice .…”

Section: Introductionmentioning

confidence: 99%

“…Previous work indicates that energy density can be maximized by finding the optimal mix of operating conditions and material composition. Randhir et al, calculated the oxygen release capacities of magnesium‐manganese oxides as a function of temperature utilizing the CALPHAD model developed by Panda et al Results showed that increasing magnesium content from pure manganese oxide increased reactive stability at high temperatures and reduced the minimum reduction temperature, leading to an increase in energy density. However, at higher levels of magnesium, the total amount of oxygen released decreases and therefore reduces energy density .…”

Section: Introductionmentioning

confidence: 99%

“…Block et al examined the Co─Mn, Cu─Mn, Mn─Al, and Mn─Fe oxide redox systems using STA experiments, finding the only observed enhancements over pure Mn‐oxides were much faster oxidation kinetics for the Cu─Mn and Mn─Fe systems. Finally, Randhir et al have demonstrated that mixing manganese oxide with magnesium oxide improves the TCES stability over pure manganese oxides.…”

Section: Introductionmentioning

confidence: 99%

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Enhancing thermochemical energy storage density of magnesium‐manganese oxides

et al. 2019

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Three approaches for enhancing the energy density of magnesium‐manganese oxide porous reactive materials for thermochemical energy storage (TCES) are investigated: adjusting the mole ratio, lowering the oxygen partial pressure during thermal reduction, and transition metal oxide doping. The manganese‐to‐magnesium molar ratios are varied to determine the composition yielding maximal energy density. The increase in energy density by lowering the oxygen partial pressure during the reduction step is also studied. Volumetric oxygen exchange capacities are measured for every case considered. Finally, the effects of doping magnesium‐manganese oxide with cobalt oxide, iron oxide, zinc oxide, and nickel oxide on the TCES properties are examined. We found the optimal Mn/Mg ratio for maximum volumetric energy density is in the vicinity of 1/1, achieving 1813 ± 175, 2178 ± 204, and 2323 ± 281 MJ m−3 for oxygen partial pressures of 0.2, 0.05, and 0.01 atm during thermal reduction, respectively; lowering the oxygen partial pressure below atmospheric during thermal reduction enhances oxygen exchange capacities and improves the energy density between 10%‐42% and 24%‐55% for oxygen partial pressures of 0.05 and 0.01 atm, respectively, with the greatest increases observed for high manganese content samples; and, doped samples exhibit reduced oxygen exchange and questionable reactive stability, thus appearing to reduce energy density.

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Section: Experimental Methodsmentioning

confidence: 71%

P_{{normalO}_{2}}

, indicating that higher energy density can be achieved.…”

Section: Introductionmentioning

confidence: 91%

P_{{normalO}_{2}}

) of 0.2 atm . The overall reversible chemical reaction utilized for energy storage is given by,

{Mg}_{x} {MnO}_{1 + x + C_{1}} \leftrightarrow {Mg}_{x} {MnO}_{1 + x + C_{2}} + \frac{C_{1} - C_{2}}{2} O_{2}

where x is the molar ratio of Mg to Mn, and C 1 and C 2 , denote the excess oxygen within the material lattice .…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enhancing thermochemical energy storage density of magnesium‐manganese oxides

et al. 2019

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Oxidation Kinetics of Magnesium‐Manganese Oxides for High‐Temperature Thermochemical Energy Storage

et al. 2020

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In this article, the high‐temperature (≥1000 °C) oxidation kinetics of porous magnesium‐manganese oxide structures considered for large‐scale thermochemical energy storage are determined. For this analysis, oxides with Mn/Mg molar ratios of 2/3, 1/1, and 2/1 are synthesized via solid‐state reaction and crushed to a powder with particle sizes ranging from 125 to 180 μm. The powder is thermally reduced at 1500 °C inside a heated alumina tube under argon flow. Subsequently, the resulting porous bed is oxidized at temperatures between 1000 and 1500 °C with an oxygen to argon molar ratio of 1:4 (leading to an oxygen partial pressure of 0.2 atm). An Arrhenius‐type kinetic rate law is derived using the theory of internal oxidation assuming spherical particles. Subsequently, the kinetic rate law parameters are identified by comparing measured oxygen flow at the reactor outlet to the oxygen output computed using a 1D plug flow reactor model incorporating the postulated kinetic model. Results indicate that the derived bulk kinetic rate law describes the measured oxidation kinetics well and is suited for designing thermochemical energy storage modules based on magnesium‐manganese oxides.

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A review on high‐temperature thermochemical heat storage: Particle reactors and materials based on solid–gas reactions

Bellan

Kodama

Gokon

et al. 2022

WIREs Energy & Environment

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In order to produce electricity beyond insolation hours and supply to the electrical grid, thermal energy storage (TES) system plays a major role in CSP (concentrated solar power) plants. Current CSP plants use molten salts as both sensible heat storage media and heat transfer fluid, to operate up to 560 C. To meet the future high operating temperature and efficiency, thermochemical storage (TCS) emerged as an attractive alternatives for next generation CSP plants. In these systems, the solar thermal energy is stored by endothermic reaction and subsequently released when the energy is needed by exothermic reversible reaction. This review compares and summarizes different thermochemical storage systems that are currently being investigated, especially TCS based on metal oxides. Various experimental, numerical, and technological studies on the development of particle reactors and materials for hightemperature TCS applications are presented. Advantages and disadvantages of different types heat storage systems (sensible, latent, and thermochemical), and particle receivers (stacked, fluidized, and entrained), have been discussed and reported.

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Magnesium-manganese oxides for high temperature thermochemical energy storage

Cited by 53 publications

References 47 publications

Enhancing thermochemical energy storage density of magnesium‐manganese oxides

Enhancing thermochemical energy storage density of magnesium‐manganese oxides

Oxidation Kinetics of Magnesium‐Manganese Oxides for High‐Temperature Thermochemical Energy Storage

A review on high‐temperature thermochemical heat storage: Particle reactors and materials based on solid–gas reactions

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