Scavenging and Turbocharging

Q. With reference to T/C give reasons for corrosion on the:

a) gas side

b) air side

c) water side.

Ans: Reasons for corrosion on gas side:

• Poor combustion and carryover of oil causes carbon build up in nozzles and blades. It prevents proper heat exchange.

• Oxide of sulphur from combustion may cause acidic corrosion under light load with low exhaust temperature.

• Vanadium & sodium ash from fuel combustion may deposit & causes local burning.

• Deposit of calcium sulphate cylinder L.O. may causes corrosion.

Reasons for corrosion on air side:

• Oil vapour & Dust from engine room may sucked by the compressor & causes corrosion on air side.

• Salty moisture which is present in the air at sea sucked by the compressor & causes corrosion.

Reasons for corrosion on water side:

• Water side may be corroded by electro- chemical if the pH value of water is low i.e. water is acidic.

• If there is inadequate protection against sea water corrosion.

• Improper cleaning schedule or PMS.