Corrosion failure
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In the atmospheric and vacuum distillation unit, water was originally added to the tower top from a sulfur treatment plant; later, due to unsatisfactory corrosion conditions in the tower top, the use of that sulfur-treated water was discontinued. Yet the corrosion problems persisted. What could be the reason for this, given that all other operating conditions remained unchanged?
Many tower tops are no longer supplied with water; our system only uses dilute ammonia and corrosion inhibitors. The wastewater contains approximately 1 ppm of iron ions, and corrosion is not monitored.
The purpose of injecting water at the top of the atmospheric pressure tower is to shift the dew point corrosion temperature downward, or in other words, to keep the tower top cooler away from that temperature. Therefore, poor corrosion conditions at the tower top are not closely related to water injection. It is recommended to analyze the product at the top of the tower to determine whether it is corroded by alkali or acid A decision will be made based on the circumstances. Generally, it is related to changes in the properties of crude oil; it is also possible to use sulfonated cobalt titanium phthalocyanine for cleaning before conducting copper sheet corrosion tests, for reference only.