The Situation
A Gulf Coast refinery processing a highly variable crude slate was continually looking for innovative mitigation strategies allowing them to run as much LTO as they could process. Their focus was how to best handle MEA contamination in the crude. The desalters already had a new online pH control system, but it failed within two months of operation.
Without a reliable means to monitor and control the acid dosage, the risk was acid over-dosing (potentially causing ETP de-nitrification issues) or under-dosing (leading to a higher potential of amine salting in the crude tower).
The refinery improved its desalter acidification for amine removal reliability; leading to a higher level of system assurance for the crude unit, while safely processing a wider range of cost-advantaged crudes.
The Results
Upon consulting with Nalco Water, the new 3D TRASARTM Technology for Brine (3DT-Brine) was installed. This unique piece of automation provides online pH, turbidity, and corrosion monitoring. It is cost effective, increases system assurance, and optimizes chemical consumption while still achieving amine removal targets regardless of the rate of LTO processed in the blend.
The pH controls the acid injection rate (5.5-6.0) and the corrosion rate (MPY) adjusts the wash water corrosion inhibitor to target less than 5 MPY. The unit can also be used to monitor oil under-carry and potentially optimize mud washing practices.
