Answer: Usually, after saturated high-temperature compressed air enters the cold dryer, the water vapor contained in it condenses into liquid water through two pathways, namely:
(1) The water vapor that directly contacts the cold surface condenses and forms dew on the low-temperature surface of the precooler and evaporator (such as the outer surface of the heat exchange copper tube, the heat dissipation fins, the baffle plate and the inner surface of the container shell) as a carrier (similar to the condensation process on the ground in nature).
(2) The water vapor that does not directly contact the cold surface condenses and forms dew on the solid impurities carried by the air flow itself as "condensation nuclei" (similar to the formation process of clouds and rain in nature).
The initial particle size of the condensed water droplets depends on the size of the "condensation nuclei". If the particle size distribution of the solid impurities mixed in the compressed air entering the cold dryer is usually between 0.1 and 25 μm, then the initial particle size of the condensed water is at least of the same order of magnitude. Moreover, in the process of following the flow of compressed air, water droplets and water droplets and cold surfaces will continue to collide and gather, and their particle size will continue to increase. After increasing to a certain extent, they will separate from the gas by their own weight.
