Investigation into the Hydration Behavior of K2CO3 Packed Beds: An NMR Study

Abstract

K2CO3 is seen as a promising heat storage material, available for applications in the domestic sector. For practical purposes, the material is hereby often employed in a packed bed containing millimeter-sized particles. To gain more insight into the hydration behavior of these packed beds, quantitative NMR measurements, capable of following the in-situ hydration behavior, are presented for the first time. It is found that hydration behavior varies significantly, depending on the specific hydration conditions that are chosen. At low airflows hydration is found to proceed via a hydration front, while higher airflows cause the hydration front to widen. Since an increase in flow rate coincided with an increase in the supplied water vapor, hydration is eventually found to proceed in a uniform manner. A comparison between TGA and NMR measurements shows that the overall packed bed hydration kinetics hereby transition to the reaction kinetics of single K2CO3 particles. Graphical Abstract

Elucidating the Dehydration Pathways of K2CO3·1.5H2O

“…Hydration/dehydration kinetics and the cyclic performance of potassium carbonate have been well studied. The hydration and dehydration kinetics of powder have been studied by Fisher et al and Gaeini et al., and the hydration kinetics of particles have been studied by Aarts et al − A detailed study on the dehydration of precycled potassium carbonate was performed by Mazur et al Cyclic testing of powder was performed by Sögütoglu et al, whereas cyclic testing of larger particles has been performed by Beving et al and Aarts et al − Testing of bed performance was done by Mahmoudi et al, Houben et al., and Raemaekers et al In addition, the effect of CO 2 on the performance of K 2 CO 3 was investigated …”