How is pipe corrosion caused?
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It is a small gas-fired vertical boiler. The smoke tubes located between the upper and lower tube sheets have been in use for less than a month, and severe corrosion has occurred in some of these smoke tubes, resulting in leaks. I would appreciate guidance on what caused this issue; please find attached a schematic diagram of the boiler along with photos of the corrosion in the smoke tubes on site
This situation is basically caused by dew point corrosion. The hydrogen-containing components in the fuel produce water upon combustion. Additionally, when the presence of chlorine and sulfur elements cannot be avoided, sulfur dioxide, hydrogen chloride, and a small amount of excess oxygen end up in the flue gases. Sulfur dioxide reacts with water to form sulfurous acid; if the amount of excess oxygen is high enough, some of this sulfurous acid is converted into sulfuric acid. Flue gases containing sulfuric acid mist are highly corrosive. The areas where corrosion occurs are usually those where the flue gas temperature starts to drop, such as the windward side of flues in the north during winter, as well as the parts of the flues that have bends and low points where water can accumulate. Raising the flue gas temperature a bit will help, but it will not eliminate corrosion. Proper desulfurization and controlling the sulfur content in fuel are effective measures to prevent corrosion.
1. From the photos you sent, it appears to be corrosion on the water side; check the water quality； 2. Many boiler manufacturers have produced boilers of this type, so it is a relatively mature technology ； 3. Take the pipe for testing to check if there are any issues with its material ； 4. Ask for the opinion of the Special Inspection Institute~
The water quality is fine, and the pipes have also passed analysis with no issues; I’m not sure what the cause could be
You’re talking about flue gas corrosion, but this is on the outside of the pipe – is it water corrosion? The water quality has passed the tests and meets the requirements, as well as the pipe material
Was it the first type of heat transfer deterioration, which resulted in a vapor cushion and led to an explosion? ? ?
Has the problem been resolved? What type of corrosion is it?
This is probably oxygen corrosion. Is there any deoxidization equipment or chemical deoxidization in the boiler feed water? It would be better to replace the pipes with stainless steel
It should be stress corrosion; the flame temperature was too high, which caused the temperature to rise further, and the support area of the support tubes was insufficient
There is a problem with the water circulation; the temperature here is the highest, but there is no water cooling, which leads to poor heat transfer and carbonization of the material. It is recommended to adjust the location of the water inlet and add downcomers.