STUDY OF CORROSION DAMAGE TO CU/NI CHLORINATOR LINE BY SEA WATER

Abstract

BACKGROUND AND CASE HISTORY

The chlorinator line which failed was delivering sea water and hypochloride to the stilling tube of sea water lift pump 29/X-OIC to treat sea water continuously with 2 ppm of hypochloride to control microorganism. After every five to six hours, shock treatment of about 5 ppm of hypochloride for half an hour was also being given. This chlorinator line was 38 mm (1.5 inch) in diameter with a wall thickness of 1.5 mm. Its material is reported to be 90-10 copper-nickel alloy. A flow velocity of 0.45 m/sec (1.5 ft/sec) was used. At times this line was shut down and thus flow was not always continuous.

Failure in the form of perforation/leak occurred at some distances from the outlet of the chlorinator line after it had been in operation for one and half years.

The objective of this study is: (i) To investigate nature/type of corrosion damage and cause of perforation. (ii) To determine chemical composition to check whether the material of chlorinator line is as per specification.

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