PURPOSE: To provide a process and device for dehumidifying wet air preferably from a liquid ring pump, especially a process and device for dehumidifying wet air sucked out of the vacuum box or dehydrator of a paper machine by a liquid ring vacuum pump and heating the air to a temperature suitable for pocket ventilation in a drying process of the paper machine.

CONSTITUTION: Wet air is brought into contact with an absorption liquid in an absorber 4 so as to form a dilute absorption liquid, at least a part of the absorption liquid is heated to the boiling point through an indirect heat exchange with a heating fluid in an evaporator 6 so as to form a condensed absorption liquid and water vapor, which are indirectly heat exchanged with a cooling fluid in a condenser 8 to condense water vapor formed by heating the absorption liquid, and the condensed absorption liquid is circulated to the absorber 4.