Abstract
To achieve decommissioning, it is important to dry wet adsorbent for contaminated water treatment in a container and to reduce the risk of leakage and spread of contamination. Accordingly, a vacuum drying apparatus using a one-third-scale cylindrical container was designed and manufactured, to understand the complex drying mechanism and determine the specifications of vacuum drying equipment. The apparatus consisted of the container, an outer cylinder with three heaters on its outer surface, a steam condenser and others. Drying experiments showed that drying proceeds from the outside of the container; initially the top of the container dries first, then the bottom dries more rapidly, and finally the bottom dries out faster than the top. Furthermore, the drying time becomes shorter with higher outer cylinder temperature and higher vacuum of the container. It was also found that the amount of condensation per unit time decreases gradually with time and the drying time could be related to when the rate of change over time of condensation amount decreases below a certain values, even when the initial saturation was changed. Using trends in this data, we suggested a method for determining the drying time. The method also uses ΔT, the difference between the heater temperature and the saturation temperature at the vacuum level, as a parameter to determine the drying time.
