Air preparation is necessary for all corona discharge ozone systems. It increases the concentration of oxygen and/or reduces the moisture content in the feed gas, improving the output capability of the ozone generator (By up to 200%!). It also keeps the long-term maintenance costs in line.

Air preparation systems fit in two general categories- air dryers and oxygen concentrators. Three basic types of dryers are currently available: Replaceable desiccant dryers are relatively inexpensive but require regular replacement of desiccant. Pressure swing absorption dryers produce the driest air but are quite mechanical and therefore require the most maintenance.

Air dryers do not significantly increase the output of the ozone generator, but they are effective in drying the feed gas to a dew point of ‚60† F. This is important because during the producing ozone, nitrogen oxides are also produced inside a corona generator. Normally benign, these nitrogen oxides form very corrosive nitric acid in the presence of moisture. Nitric acid can rapidly deteriorate critical internal parts of the ozone generator, resulting in reduced ozone production (see chart) and increased maintenance costs.

Oxygen concentrators dry the feed gas up to a ‚100† F dew point and remove a large percentage of the percentage of the nitrogen. Nitrogen is more abundant in ambient air than oxygen (about 78% vs. about 20%) and its removal from the feed gas increases the concentration of oxygen, leading to improved ozone output and concentrations. Depending on the type of ozone generator, the concentration ozone by weight can be increased by up to 200%!

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