How does a membrane dryer (type LD) work?
The dryer consists of a large number of coated hollow fibre membranes, positioned in parallel to one another in a longitudinal direction. Air flows through these fibres in the longitudinal direction and molecules of water can then penetrate the sidewalls of the hollow fibres. Some of the air that has already been dried is released along the external surfaces of the fibres. This drier air absorbs the moisture already located on the outside of the fibres and carries it along into the atmosphere (drying current). The drier external surfaces of the hollow fibres gives rise to a concentration gradient between the moister air within the fibre and the drier air outside of the fibre. This leads to the diffusion of water from the internal surface to the external surface of the fibre.
