Abstract
Oil & gas industries utilize fresh cooling water as a cooling medium for many of their process equipment. Quality of the water is very important in order to ensure the continued integrity and reliability of these systems.
This paper discusses various corrosion issues in heat exchangers within the closed loop cooling water system due to water quality. A detailed study was performed to determine the root cause of the corrosion failures which was validated by metallurgical analysis, water chemistry analysis, microbiological study, sludge analysis and inspection of the exchangers.
The paper further discusses trouble shooting and mitigation methods such as improvements in chemical treatment, system monitoring, inspection strategy, and system operation, which resulted in significant improvement in Cooling water integrity, and overall system reliability. It also details the importance of cleaning and passivation of cooling water systems prior to commissioning.
The paper concludes that inadequate system cleaning during system start-up, chemical treatment and monitoring are the root cause of corrosion issues. The recommendations of the study includes corrosion control methods such as optimizing corrosion inhibitor and biocide dosages and frequency, and improvement in fresh cooling water monitoring programme by means of monitoring key process parameters.
