Why nitrogen gas only is used for purging?
*most importantly cost effective. *Nitrogen offers significant advantages for this application over water or air by providing an inert atmosphere with a very low dew point. i.e- It is dry, clean and reduces oxidation. *Desiccator cabinets must be set up so that an appropriate flow of nitrogen forces out all moisture- and contamination-laden air. Because nitrogen has a lower specific gravity than air, it is introduced into the upper section of the desiccator; the heavier air is then purged out of the bottom. *Nitrogen purging is an industry standard technique for the replacement of a hazardous or undesirable atmosphere with an inert dry atmosphere. The two most common methods of purging are displacement and dilution. The geometry of the process system determines which method is used. For simple systems, displacement purging is usually more effective in terms of time and cost but, for more complex systems, dilution purging is used. *Elemental nitrogen is a colorless, odorless, tasteless
