The present invention is process and apparatus for recovering and utilizing energy of waste hot and humid air from drying machine. The waste hot and humid air is first introduced into hot water to recover latent heat and sensible heat from the waste hot and humid air, and the high temperature hot water is led to a flash tank, where partial high temperature hot water is converted into secondary steam with a steam jetting pump. The secondary steam is then mixed with fresh steam before being used for drying, concentrating evaporation and other steam using operation. |