ReliabilityEngr2022
Mechanical
Hi,
I am looking for some help in figuring out root cause of a plate type heat exchanger leakage at our site.
It's an evaporator which receives sodium hydroxide at 38% concentration and increases the concentration to 46.5% by heating the contents by saturated (condensing) steam at 135 degree C. Material of the plates is Nickel 200. Exchanger has been in service for last 3 years. Thickness of plates is 0.8 mm. According to OEM, the exchanger plates should last for 14 to 15 years without any leakage. However, they have cautioned against contamination of sodium hydroxide feed with sodium chlorate or sodium hypochlorite as these can cause accelerated corrosion. Unfortunately, we have not been able to control the chemistry and have known to introduced small quantities (less than 1%) of sodium chlorate / chlorides in our feed.
Leakage occurred at the bottom of the plates near the discharge port as can be seen in the attached pictures.
Please fee free to ask further questions for better understanding of the situation.
Regards,
I am looking for some help in figuring out root cause of a plate type heat exchanger leakage at our site.
It's an evaporator which receives sodium hydroxide at 38% concentration and increases the concentration to 46.5% by heating the contents by saturated (condensing) steam at 135 degree C. Material of the plates is Nickel 200. Exchanger has been in service for last 3 years. Thickness of plates is 0.8 mm. According to OEM, the exchanger plates should last for 14 to 15 years without any leakage. However, they have cautioned against contamination of sodium hydroxide feed with sodium chlorate or sodium hypochlorite as these can cause accelerated corrosion. Unfortunately, we have not been able to control the chemistry and have known to introduced small quantities (less than 1%) of sodium chlorate / chlorides in our feed.
Leakage occurred at the bottom of the plates near the discharge port as can be seen in the attached pictures.
Please fee free to ask further questions for better understanding of the situation.
Regards,
