Bubble Cap and Packing Distillation Tower

In trays and bubble cap distillation tower the holes in each tray are covered with caps called bubble caps. The slots in these bubble caps disperse the raising vapor through the liquid on the tray. Each bubble cap has many slots and each tray has many bubble caps to spread up the vapor. This ensures maximum contact between vapor and liquid so that maximum heat transfer can take place.

Another type of tower called the pack tower contains layers of devices called packing instead of trays with bubble cap. There are many different type of packing, some tower have section filled with cylindrical ring known as raschig ring another type of packing is known as a berl saddle. The packing breaks up the liquid so that it flows over a large amount of surface area. This exposes more liquid to the vapor and increase heat transfer from the vapor to the liquid. Packing can be made from many different materials including porcelain, cooper, aluminum and iron. The main requirement is that the material must be compatible with the liquid in the tower and the condition under wish the tower is operated.

Packing grid
Each layer in the grid has spaces for vapor to rise through the packing on the way up the tower. Liquid flow over these surfaces which channel the liquid as it flow down the tower. Packing grid provides a great deal of surface area where contact between the vapors and liquid can take place so heat transfer is maximized.


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