Corrosion Monitoring on Refinery Crude Unit Overheads for Process Optimization

Crude tower overhead corrosion has been well studied and documented over many years. The aggressiveness of the corrosive attack in the overhead system is a function of the amount of chloride present in the system. The highest risk location for failure occurs at the point where the first droplet of hydrochloric acid condenses, because this has a very low pH, known as the dew point. A principle mitigation strategy for crude overhead acid corrosion is chemical treatment as this can be carried out on-the-run without the need for shutdown. The use of 'Real-time’ corrosion data from sensors installed on the crude overhead piping system provides an effective understanding of the effectiveness of the overhead chemical treatment program, allowing the operator to adjust dosage of treatment chemical to stabilize corrosion and prevent unplanned outages or loss of containment. This in turn leads to an increase to the plant equipment life and process safety.