Bed Evaporator Tube Leakage

WHat does the Engineer/Surveyor for the company supplying burst indemnity insurance for the boiler have to say? What is on the periodic inspection reports that this organisation has issued?

What does the company managing the make-up water treatment regime have to say on the subject?

I'm inclined to say the boiler chemistry is way out of control.

Thanks Sir,

we will again study the last month water Chemistry. pl suggest any other MOC for BET tubes.

Regards.

If I remember correctly, dissolved oxygen in the boiler water can cause pitting corrosion on the water side of the tubes. Deposits (scaling) would not necessarily be present. Feedwater deaeration can help, or chemical treatment (I forget what kind of acid).

Dear Sir,

we will again study the water chemistry as u suggest, i would also like to know that will changing the MOC of BET will do and what Carbon steel we can deploy.

Thanks.

You're right that dissolved oxygen eats metal quick and should definitely be looked into. From the OP I assumed a bulk loss, such as thinning and from what I recall, the major cause for loss of metal in this way is pH. It's been years since I've studied the corrosion rates/causes, but I remember a low pH removing metal in this fashion and a high pH causing pitting similar to a high DO content.

There is another method of corrosion related to plant cycling, specifically heat up rates. If the ramp rates for the boiler heat up is too high, there can be localized areas where the pH is driven too high leading to caustic corrosion.

If the problem is a general thinning though, I'd guess the pH was too low.