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Sand dryer is a type of industrial dryer employed to reduce or minimize the liquid moisture content of the material it is handling by bringing it into direct contact with a heated gas.
Sand dryer is made up of a large, rotating cylindrical tube, usually supported by concrete columns or steel beams. Sand dryer slopes slightly so that the discharge end is lower than the material feed end in order to convey the material through the dryer under gravity. Material to be dried enters sand dryer, and as sand dryer rotates, the material is lifted up by a series of internal fins lining the inner wall of sand dryer. When material gets high enough to roll back off the fins, it falls back down to the bottom of sand dryer, passing through the hot gas stream as it falls.
This gas stream can either be moving toward the discharge end from the feed end (known as co-current flow), or toward the feed end from the discharge end (known as counter-current flow). The gas stream can be made up of a mixture of air and combustion gases from a burner, in which case sand dryer is called a direct heated dryer.
