Tuning the performance of MgO for thermochemical energy storage by dehydration – From fundamentals to phase impurities

Müller, Danny; Knöll, Christian; Gravogl, Georg; Artner, Werner; Welch, Jan M.; Eitenberger, Elisabeth; Friedbacher, Gernot; Schreiner, Manfred; Harasek, Michael; Hradil, K.; Werner, Andreas; Miletich, Ronald; Weinberger, P.

doi:10.1016/j.apenergy.2019.113562

Cited by 16 publications

(9 citation statements)

References 46 publications

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“…A reduction in the particle volume [52][53][54] and/or an increase in the specic surface area could also be achieved. 53,81,83,84 These can potentially promote the process of diffusion of water into the porous bulk structure. 76 Water diffusion could be ascribed to the drastic hydration conversion change at the initial hydration stage 76 The third step involves the rapid formation, and annealing out of the resulting crystal defects (e.g., edge dislocations) formed during the intergrowth of the nanocrystals.…”

Section: Hydration Of Pure and Chemically-modied Mgo: Probable Hydration Pathwaymentioning

confidence: 99%

Fourier-transform infrared and X-ray diffraction analyses of the hydration reaction of pure magnesium oxide and chemically modified magnesium oxide

2021

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Section: Hydration Of Pure and Chemically-modied Mgo: Probable Hydration Pathwaymentioning

confidence: 99%

Fourier-transform infrared and X-ray diffraction analyses of the hydration reaction of pure magnesium oxide and chemically modified magnesium oxide

2021

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“…Mg(OH) 2 was considered at reactor scale, and an economical study was conducted [28]. However, the material suffers from slow and incomplete rehydration, as stated by Müller et al (2019) [29]. The authors recently studied the rehydration mechanism of MgO and of natural magnesite in order to assess the effect of impurities on the reaction.…”

Section: Tces Systems Based On Hydroxidesmentioning

confidence: 99%

Recent Advances in Thermochemical Energy Storage via Solid–Gas Reversible Reactions at High Temperature

André

Abanades

2020

Energies

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The exploitation of solar energy, an unlimited and renewable energy resource, is of prime interest to support the replacement of fossil fuels by renewable energy alternatives. Solar energy can be used via concentrated solar power (CSP) combined with thermochemical energy storage (TCES) for the conversion and storage of concentrated solar energy via reversible solid–gas reactions, thus enabling round the clock operation and continuous production. Research is on-going on efficient and economically attractive TCES systems at high temperatures with long-term durability and performance stability. Indeed, the cycling stability with reduced or no loss in capacity over many cycles of heat charge and discharge of the material is pursued. The main thermochemical systems currently investigated are encompassing metal oxide redox pairs (MOx/MOx−1), non-stoichiometric perovskites (ABO3/ABO3−δ), alkaline earth metal carbonates and hydroxides (MCO3/MO, M(OH)2/MO with M = Ca, Sr, Ba). The metal oxides/perovskites can operate in open loop with air as the heat transfer fluid, while carbonates and hydroxides generally require closed loop operation with storage of the fluid (H2O or CO2). Alternative sources of natural components are also attracting interest, such as abundant and low-cost ore minerals or recycling waste. For example, limestone and dolomite are being studied to provide for one of the most promising systems, CaCO3/CaO. Systems based on hydroxides are also progressing, although most of the recent works focused on Ca(OH)2/CaO. Mixed metal oxides and perovskites are also largely developed and attractive materials, thanks to the possible tuning of both their operating temperature and energy storage capacity. The shape of the material and its stabilization are critical to adapt the material for their integration in reactors, such as packed bed and fluidized bed reactors, and assure a smooth transition for commercial use and development. The recent advances in TCES systems since 2016 are reviewed, and their integration in solar processes for continuous operation is particularly emphasized.

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“…In our previous studies, we investigated the influence of metal doping in Mg(OH) 2 synthesis, examining the thermochemical comportment, depending on different structural, morphological as well as thermochemical characteristics [ 32 ]. To determine if the thermochemical behavior of Mg(OH) 2 may be improved without chemical doping, Müller and co-workers systematically studied the dehydration conditions’ effects on the subsequent rehydration reaction [ 33 ]. It was shown that dehydrated samples with larger Brunauer–Emmett–Teller (BET)-surface area resulted in the most reactive MgO-species, with higher re-hydration conversions [ 33 ].…”

Section: Introductionmentioning

confidence: 99%

“…To determine if the thermochemical behavior of Mg(OH) 2 may be improved without chemical doping, Müller and co-workers systematically studied the dehydration conditions’ effects on the subsequent rehydration reaction [ 33 ]. It was shown that dehydrated samples with larger Brunauer–Emmett–Teller (BET)-surface area resulted in the most reactive MgO-species, with higher re-hydration conversions [ 33 ]. Aiming to achieve high efficiency Mg(OH) 2 synthesis production, Kim et al increased the MgO surface area by forming micro-beams on the surface of the millimeter-size MgO pellets by electron beam irradiation [ 34 ].…”

Section: Introductionmentioning

confidence: 99%

Tuning Mg(OH)2 Structural, Physical, and Morphological Characteristics for Its Optimal Behavior in a Thermochemical Heat-Storage Application

et al. 2021

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Thermochemical materials (TCM) are among the most promising systems to store high energy density for long-term energy storage. To be eligible as candidates, the materials have to fit many criteria such as complete reversibility of the reaction and cycling stability, high availability of the material at low cost, environmentally friendliness, and non-toxicity. Among the most promising TCM, the Mg(OH)2/MgO system appears worthy of attention for its properties in line with those required. In the last few decades, research focused its attention on the optimization of attractive hydroxide performance to achieve a better thermochemical response, however, often negatively affecting its energy density per unit of volume and therefore compromising its applicability on an industrial scale. In this study, pure Mg(OH)2 was developed using different synthesis procedures. Reverse deposition precipitation and deposition precipitation methods were used to obtain the investigated samples. By adding a cationic surfactant (cetyl trimethylammonium bromide), deposition precipitation Mg(OH)2 (CTAB-DP-MH) or changing the precipitating precursor (N-DP-MH), the structural, physical and morphological characteristics were tuned, and the results were compared with a commercial Mg(OH)2 sample. We identified a correlation between the TCM properties and the thermochemical behavior. In such a context, it was demonstrated that both CTAB-DP-MH and N-DP-MH improved the thermochemical performances of the storage medium concerning conversion (64 wt.% and 74 wt.% respectively) and stored and released heat (887 and 1041 kJ/kgMg(OH)2). In particular, using the innovative technique not yet investigated for thermal energy storage (TES) materials, with NaOH as precipitating precursor, N-DP-MH reached the highest stored and released heat capacity per volume unit, ~684 MJ/m3.

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Tuning the performance of MgO for thermochemical energy storage by dehydration – From fundamentals to phase impurities

Cited by 16 publications

References 46 publications

Fourier-transform infrared and X-ray diffraction analyses of the hydration reaction of pure magnesium oxide and chemically modified magnesium oxide

Fourier-transform infrared and X-ray diffraction analyses of the hydration reaction of pure magnesium oxide and chemically modified magnesium oxide

Recent Advances in Thermochemical Energy Storage via Solid–Gas Reversible Reactions at High Temperature

Tuning Mg(OH)2 Structural, Physical, and Morphological Characteristics for Its Optimal Behavior in a Thermochemical Heat-Storage Application

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