| Popis: |
In this work, a numerical study is performed to analyze the reaction kinetics and associated transport phenomena pertaining to the dissociation mechanism of salt hydrates (Epsom salt [MgSO4·7H2O]). During the dissociation process, the salt hydrate dissociates into a lower hydrate or an anhydrate and evolves water vapor. The chemical energy used for the process of dissociation gets stored in the lower hydrate or anhydrate in the form of bond formation internal energy. This energy can be recovered back either by passing water vapor through it or by extracting a heat flux, thus converting the stored chemical energy into sensible heat. For this, a macroscopic model of decomposition of salt hydrate has been presented by taking into account solid-state chemical kinetics, thermodynamics and associated transport phenomenon. Equations of chemical rate, mass and energy have been coupled employing a single domain continuum formulation and have been solved numerically for the process of diffusion. Subsequently, the influence of reaction kinetics on the heat storage and heat transfer behavior is described. Further, an energy analysis during the dissociation process is delineated. The model is able to predict temperature and concentrations of all the attendant species during the thermochemical dissociation reaction. The insights from the current study can develop a deeper understanding of the decomposition process and can be useful in designing thermal energy storage (TES) systems using salt hydrates. |
