Simulation of Drying for Multilayer Membranes

In ceramic membrane preparation, drying variables and its phenomena are very important to ensure no defects and failures in membrane layers. Generally, ceramic membrane consists of several layer with the top structure or layers possesses a very hygroscopic zone that acting as a separator while next two layers are non hygroscopic zone. Combination of these two different multilayer systems that exhibit different properties always associated to the failure of ceramic consolidation structure during the drying and sintering process. Therefore,controlling of drying behavior is very important to ensure a consistent shrinkage exist between these two layers system. Thus in this present work, the drying process of multilayer materials was studied and observed via simulation technique. A two dimensional mathematical model that coupled mass, heat and gas transfer was employed. Finite element method was used to solve the model and numerically compute using Skyline solver to capture highly nonlinear and transient process. The results showed that drying of multilayer material for membrane structure is obviously different from drying of single layer system. Separation zone that acting as hygroscopic zone does play its roles towards effecting higher pore water pressure and gas pressure. Thus, different drying factors can be seen in the layering system. Hence, understanding those drying factors that may cause inhomogeneous shrinkage due to the existence of different porous network in membrane layers is essential to avoid ceramic membrane failure.