Perma Pure PD-Series™ gas dryers are multi-tube Nafion dryers designed for high flow, high performance gas drying applications. These dryers can be used to dry to -45°C without removing other compounds. PD-Series dryers consists of a bundle of 0.030 O.D. Nafion tubes housed within a single large tube shell. Feed gas flows within the Nafion tubes while water vapor absorbs into the tubular membrane walls and is removed. Moisture permeating the tubing is carried away by a dry purge gas within the shell that flows countercurrent to the feed. Purge gas should be instrument quality air (-40°C dew point) or nitrogen flowing at two to three times the sample flow rate. To learn more about the drying process see: Our Technology.

Applications for PD-Series gas dryers include gas sample conditioning for continuous emissions and process monitoring. In these applications, sample gases flowing through the Nafion tubing are dried without removing any of the sample analytes. PD-Series dryers are also used as moisture exchangers in fuel cell applications. Fuel cell exhaust gases transfer their moisture and heat to the dry inlet gases (primarily hydrogen).  Finally, PD-Series gas driers can be used in small scale process applications. Process applications take advantage  of one or more of the unique properties of Nafion: highly efficient and selective moisture exchange, ion exchange capabilities, and extreme corrosion resistance.