Internal impurity issues in methanol washing
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A few days ago, the filters in the methanol washing heat zone were cleaned. The material that came out of them resembled coal sludge in appearance – it was black and viscous. After sending it for analytical testing, it was found that the iron content was around 60%, while the acid-insoluble substances accounted for about 5%. Does this mean that the system is suffering from severe corrosion? Otherwise, how could there be such a high iron content? What other analyses are usually needed for something like this type of scale? Please give me some guidance
Was the equipment and pipelines not acid-washed before starting operation originally?
It’s ferrous sulfide; there is more of it at the inlet of the filter in high-temperature areas, and it can catch fire on its own, releasing sulfur dioxide. When cleaning a filter and encountering spontaneous combustion, do not try to put out the fire immediately. Sulfur dioxide is heavier than air; if inhaled, it can cause hallucinations as well as discomfort in the throat and nose that may last for a month. Don’t ask me how I know this – I’ll never forget it in this life. P04161:o
We have encountered this issue twice with the backflow from the reboiler at the inlet of the methanol-water washing tower in our plant; what was removed was also something similar to coal ash