Crude oil receipts that have basic sediment and water (BS&W) levels above 0.5 percent can potentially benefit from additional water separation. Tankage pretreatment (dehydration), in which specific demulsifer chemistry is added to the crude as it is received, is often recommended under the following conditions:

• Crude receipts are inconsistent in quality (usually barge or tanker shipments)
• Crude receipts contain >0.5 percent water
• Poor water/oil separation is seen in tank farm operations
• Salt concentration in the desalted crude is consistently high
• The desalter system is running at or above design resulting in overhead chloride targets that are difficult to achieve.

Stabilizing the quality of the crude being fed to the desalters often results in reduced demulsifier dose rates at the desalter and a reduction in the frequency of desalter upsets and their associated impacts on downstream units.