Continuous Horizontal Centrifuge

Assignment on Continuous Horizontal Centrifuge

1. Ass ignm ent on Continuous Horizontal Centrifuge Presented By Md. Masum Billah ID. Bhp-160101282 Department of Pharmacy Northern University Bangladesh

2. Overview Definition Classification Principal Construction Working principal Advantage Disadvantage

3. Definition Centrifugation is a unit operation employed for separation the constituents present in a dispersion with the aid of centrifugal force. Centrifugal force is used to provide the driving force for the separation. It replaces gravitation forces in the sedimentation. Centrifugation is particularly useful when separation by ordinary filtration is difficult, for example, separating highly viscous mixtures mixture and colloidal dispersions (particles size less then 5 mm)

4. Classification of Centrifuges Sedimentation centrifuge Filtration centrifuge Perforated basket centrifuge Non perforated basket centrifuge Semi-continuous centrifuge Continuous horizontal centrifuge

5. Continuous horizontal centrifuges cont. Figure. Construction of the Continuous horizontal centrifuge

6. Continuous horizontal centrifuge cont. Principle: This is a sedimentation centrifuge. The separation is based on the difference in the densities of solid and liquid phases without borders barrier. When the slurry is introduced through the shaft of the screw element into a conical bowl, sedimentation of solids takes place due to centrifugal action. The solids are lifted up by the screw element, while the liquid phase is continuously drained.

7. Continuous horizontal centrifuge cont. Construction: The construction of a horizontal continuous centrifuge is shown in Figure. It consists of a cylindrical or conical bowl mounted horizontally and capable of rotating at 50 to 65 revolutions per second. The bowl has a diameter of about 0.5 metres . Within the bowl, a screw . conveyor is placed which rotates in the same direction as the bowl , but at a slightly slower speed .

8. Continuous horizontal centrifuge cont. Working: The bowl and the screw conveyor are allowed to rotate using suitable power supply. The slurry is introduced through the shaft. The liquid moves into the wider portion of the bowl. Sedimentation of solids takes place due to centrifugal action. The solids are listed by the screw element, while the liquid phase is continuously drained. The solid material is carried towards outlet by the conveyor and is discharged continuously. The solids are conveyed to a dry 'beach' where they get dried.

9. Continuous horizontal centrifuge cont. Uses: Horizontal continuous centrifuge is used when a high proportion of solids is present in the slurry , Advantages: 1 . Continuous centrifuge is very flexible in operation. 2 . It is capable of handling solids as large as 10 to 15 millimeters or as small as a few microns. 3. It can be used for slurries with concentrations ranging from 0.5 to 50%. Variants

10. Continuous horizontal centrifuge cont. Disadvantage 1. The machine can be very noisy can cause vibration 2. The device has a high energy consumption