Priming and foaming

priming and foaming

1. SEMINAR TOPIC : PRIMING & FOAMING BY, MITHUN .T ROLL NO :38 S1S2 ME

2. PRIMING Due to rapid boiling, the steam may carry some water droplets along with it. This is called wet steam The process of wet steam production is called Priming.

3. CAUSES OF PRIMING Priming can reduce the heat of the steam Priming can cause corrosion in the pipelines

4. PRIMING IS DUE TO a) Improper design of boiler b) High water level c) High velocity of steam d) Uneven boiling

5. PRIMING CAN BE CONTROLLED BY Proper boiler design Maintaining proper water level Proper boiling

6. FOAMING If oils and greases are present, they produce stable bubbles on the water surface. This will increase the wet steam production. This is known as “Foaming

7. FOAMING IS PREVENTED BY ADDING Anti foaming agents (e.g.) synthetic poly amides , castor oil Coagulants (e.g.) Aluminium hydroxide

8. FOAMING AND PRIMING ARE COLLECTIVELY KNOWN AS “ CARRY OVER”.