Simulation of vacuum heating and drying process of wet adsorbent particle packed bed in a vessel of actual scale diameter

Abstract

Dry storage of adsorbent reactors after contaminated water treatment in decommissioning contributes to reducing the risk of contamination spread. In general, the drying process of wet particles involves the simultaneous heat and mass transfers in the particle bed, and the thermal flow becomes complicated. In this study, a simulation model considering the physis involved in the bed, such as the structure of the vessel, the distribution of the initial moisture content, and the resistance of heat and mass transfer, was presented. Predictive calculations of the temperature and moisture content in the drying bed in full-diameter vessel were then performed. In addition, the reproductions of the temperature and the amount of evaporation were confirmed by comparison with the actual measurement results. This model was useful for examining heating methods and predicting drying time. Approximately 100 hours after the start of heating, the adsorbent in contact with the inner surface and bottom of the steel container was dried, and it was thought that it is possible to prevent moisture from coming into contact with the container even during long-time storage. Furthermore, by appropriately setting thermal boundary conditions on the top surface of the packed bed, it was able to improve the prediction accuracy of local moisture content.