A method and apparatus for removing water from compressed air is disclosed. The method includes the steps of passing a stream of compressed air through a pressure swing adsorption (PSA) dryer. The dryer includes at least one vessel containing a desiccant material bound into pieces, for example tubes, using a polymer binder. The PSA dryer also has a control system for controlling the flow of the compressed air and switching between drying and purging modes. In particular the vessel and desiccant material contained therein are sized to produce a dew point suppression of less than 50° C.