Development of a Moving Bed Reactor for Thermochemical Heat Storage Based on Granulated Ca(OH)2

Calcium hydroxide is promising for thermal energy storage due to its low cost and high energy density. Nevertheless, the powdered material is cohesive and has low thermal conductivity which is a major challenge for the operation of moving bed reactors. One approach to facilitate the movement of the...

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Bibliographic Details
Published inProcesses Vol. 10; no. 9; p. 1680
Main Authors Cosquillo Mejia, Aldo, Afflerbach, Sandra, Linder, Marc, Schmidt, Matthias
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.09.2022
Subjects
Alternative energy sources
Aluminum oxide
Calcium hydroxide
Coatings
Design
Energy storage
Fixed bed reactors
Gas flow
Granular materials
Granulation
Heat conductivity
Heat exchangers
Heat storage
Heat transfer
Hydration
Kilns
Movement
Moving beds
Phase composition
Slaked lime
Stability analysis
Steel pipes
Structural integrity
Structural stability
Thermal conductivity
Thermal energy
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Summary:Calcium hydroxide is promising for thermal energy storage due to its low cost and high energy density. Nevertheless, the powdered material is cohesive and has low thermal conductivity which is a major challenge for the operation of moving bed reactors. One approach to facilitate the movement of the reaction bed is the stabilisation of the particles through the coating of Ca(OH)2 granules with Al2O3 particles. In this work, a newly designed reactor concept was specifically developed for testing coated Ca(OH)2 granules. The design allows for the movement of the reaction bed by gravity assistance and direct heating of the particles by a counter current gas flow. The operation was successfully demonstrated and proved to achieve high heat transfer between gas and granules. Furthermore, the movement of the reaction bed was achieved after the discharging phase. Two batches of uncoated and coated Ca(OH)2 granules were subject of 10 thermochemical cycles in this reactor. The cycling stability, structural integrity, mechanical stability, morphology and phase composition of the granules were analysed. Full conversion of both samples was demonstrated for the entire experimental series. It was found that the alumina coating enhances the mechanical stability of the granules under reaction conditions.
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ISSN:2227-9717
2227-9717
DOI:10.3390/pr10091680