The rotary dryer is a type of industrial dryer that reduces the moisture content of materials by bringing them into direct contact with heated gas. It consists of a cylindrical shell that rotates, allowing material to be fed in at one end and discharged at the lower end as it dries. As the dryer rotates, internal fins lift the material through a hot gas stream to evaporate moisture before it falls back to the bottom. Rotary dryers can dry a wide range of materials effectively and are commonly used in mineral processing to dry products like sands, limestone, ores, and coal.

1. UNIT OPERATION 2
REPORTED BY: CANOY, CLAIRE
2B2- CHEMICAL ENGINEERING TECHNOLOGY

2. ● 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

3. • A cylindrical furnace slightly inclined to the
horizontal and rotated on suitable bearings;
moisture is removed by rising hot gases.
• rotary dryer for processing products with
high moisture content.

4. • Rotary dryers are suitable for drying a wide
range of materials
• It can be widely used to dry various
materials, and it is simple to be operated.

5. 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.

6. A rotary dryer consists of a cylindrical shell, set
with its axis at a right angle to the horizontal and
mounted on rollers so that it can be rotated. The
material to be dried is fed to the high end of the dryer
and , by rotation of the dryer, usually assisted by
internal shelves of flight , is gradually advanced to the
lower end where it is discharged. The source of heat for
a rotary dryer is usually the hot air that circulates
through the using dryer.

7. The characteristic dimensions are :
● Rotary dryer ID = D =110 mm = 0.11 m
● Dryer length = 1500 mm = 1.5 m
● Pre - heating of air g 1.5 KW heater (2 nos)
● Air flow rate measurement by a pitot tube
● Solid feed : By a screw conveyor
● Inlet / Outlet air temperature by a hygrometer.

10. Type and
Specification
(mm)
Rotary Speed
(r/min)
GZ800*8000
3.8
5
GZ1000*10000
3.8
GZ1200*10000
Temperature of
Inlet Air
Production
Capacity(t/h)
Weight(t)
700
0.8-2.0
3.5
5
700
1.0-3.5
5.6
3
3
700
1.8-5
14.04
GZ1500*12000
2.08
5
800
3.3-7.5
17.76
GZ1800*14000
2.08
5
800
5-9
29
GZ2200*12000
4.7
5
700
6-12
33
GZ2400*18000
4
5
800
10-15
53.3
Pitch (%)
(centigrade)

11. Rotary Dryers have many applications
but are most commonly seen in the mineral
industry for drying sands, limestone, stones
and soil, ores, fertilizers, wood chips, coal,
iron sulphate, filter cakes, sewage sludge, etc