Klaus Afflerbach; Sandra Afflerbach; Reinhard Trettin; Wolfgang Krumm
Abstract
One major scientific challenge is a shift of the energy generation and utilization towards sustainability and efficiency. Therefore, thermochemical heat storage concepts offer a promising contribution as for example by integration in Concentrated Solar Power (CSP) applications. The reaction system Ca(OH)2/CaO ...
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One major scientific challenge is a shift of the energy generation and utilization towards sustainability and efficiency. Therefore, thermochemical heat storage concepts offer a promising contribution as for example by integration in Concentrated Solar Power (CSP) applications. The reaction system Ca(OH)2/CaO is seen as a superior candidate but its poor powder properties yet hinder a technical implementation. The authors have recently proven, that these obstacles can be overcome by a persistent particle size stabilization of the pre-granulated storage material. Within the present study, the mechanical capsule material properties are improved by admixing of additives to the powdery precursor. By thermochemical conversion in a laboratory reactor, the cyclability and the suitability for moved reaction beds of the storage material is proven. The investigations are complemented by attrition tests on the most promising sample material and an encapsulated reference material. It is shown that the chemically enhanced encapsulation is a suitable approach to retain good flow properties and reduce attrition significantly. An encapsulated sample with an enhanced shell material composition containing 5%(w/w) of diatomaceous earth and 1%(w/w) of flux agent is found to be of superior stability over ten thermochemical cycles. A comparative macroscopic evaluation of the sample material after tenfold thermochemical cycling emphasizes the potential of this approach.
Barbara Lipowska; Bronisław Psiuk; Mirosław Cholewa
Abstract
Cellular SiC/iron alloy composite with a spatial structure of mutually intersecting skeletons created with a porous ceramic preform has not been obtained before, despite promising spectrum of potential uses. We tested the possibility of obtaining such material using a SiC material with an oxynitride ...
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Cellular SiC/iron alloy composite with a spatial structure of mutually intersecting skeletons created with a porous ceramic preform has not been obtained before, despite promising spectrum of potential uses. We tested the possibility of obtaining such material using a SiC material with an oxynitride bonding and grey cast iron. Porous ceramic preforms were made by pouring the gelling ceramic suspension over a foamed polymer base which was next fired. The obtained samples of materials were subjected to macroscopic and microscopic observations as well as investigations into the chemical composition in microareas. It was found that the minimum width of a channel in the preform, which in the case of pressureless infiltration enables molten cast iron penetration, ranges from 0.10 to 0.17 mm. It was also found that the ceramic material applied was characterized by good metal wettability. Were the channels are wide enough for the metal penetration we observed that the ceramics/metal contact area always has a transition zone in which mixing of both components takes place.
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