What causes peeling of the furnace tubes in a reformation four-in-one heating furnace?
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The heating furnace in our workshop is a box-type furnace with square sides. Last year, an air preheater was installed, which enabled the heating furnace to achieve an efficiency of over 92%; however, after its installation, peeling began to occur on the furnace tubes. Normally, the oxygen content in the heating furnace (in both the left and right sides) is kept at around 3.5%. Could everyone help me analyze what’s going on?
Severe oxidation causes peeling of the furnace tubes. The excess air is too high. But it seems that the oxygen level at 3.5 isn’t high. The oxygen level can be lowered a bit more and observed for some time; a certain amount of oxygen is sufficient to ensure proper combustion. It’s also possible that steam might get mixed in, who knows.
The furnace temperature should be higher than before.
Why are we taking the steam drum?
I think the oxygen level measurements you are obtaining are not accurate enough; calibrate your online oxygen monitors. Additionally, you can try reducing the total air flow gradually during operation – as long as the combustion in the furnace is bright and no black smoke comes from the chimney, this will also help determine whether there is any deviation in the readings provided by your online oxygen monitors.
Oxidative scaling occurs when the excess air coefficient is too high; it may be advisable to use a flue gas analyzer for comparison with zirconia
Reply 1# zhelly: What material are your furnace tubes made of?
Air preheaters on reformation four-in-one furnaces are quite rare. Could you provide more details? I’m interested in learning how to achieve a high thermal efficiency in such systems
High-temperature oxidative corrosion: reducing the oxygen content slightly helps, but it is inevitable.
Keeping the oxygen content around 3.0 is sufficient; we keep it at around 3.
Could it be that the gas desulfurization level does not meet the standards?