The rotary 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. The dryer is made up of a large, rotating cylindrical tube, usually supported by concrete columns or steel beams. Direct rotary kiln dryers are the most versatile and simplest form of drying. The kilns specifications are determined by the material, how much drying, and how long must it be in the drying process.

These dryers are suited for material that are not required to be isolated from a burning system. The rotary dryer is a type of industrial dryer employed to reduce or minimize the liquid moisture content of the material by bringing it in direct contact with a heated gas.The dryer is made up of large rotating cylinder which slopes slightly so that the discharged end is lower than the material feed end in order to convey the material under gravity.Material to be dried enters the dryer and as the dryer rotates,the material is lifted up by a series of internal fins lining the inner wall of the dryer.When materials fall back to the bottom,it passes through the hot gas stream.In the experiment , the gas stream moves towards the feed end from the discharge end (counter current flow).

Also the material passes through the length of the dryer at nearly the wet - bulb temperature.Typical direct rotary kiln dryers also run some level of oxygen in the system. The 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.

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