(103g) Smart, Integrated Approach to Capturing Acid Crude Value

Oil refineries are designed to run on a range of crude oils, so they can quickly respond to changing markets. However so called ?opportunity' crudes have a variety of properties which make them undesirable to the refiner. Acid crude is just one such ?opportunity' crude they may consider.

Acid crudes are found throughout the world, normally in shallow oil fields that have undergone microbial decomposition, accounting for about 10% of supply. However, if used as raw material, it can cause corrosion problems, leading to an elevated risk of line failure in certain areas of oil refineries. As a result, demand for acid crude is often lower than conventional crude oils, and the market discounts significantly, depending on the acidity level.

To handle the increased corrosion risk, refiners traditionally invest heavily in upgraded metallurgy of key refinery units, often using expensive stainless steels. This increased cost is not always economically justified given the variability of acid crude discounts. Therefore, if a way could be found to safely and economically increase the percentage of acid crudes processed, refiners could begin to use this less-expensive raw material to increase their margins.

In 1998, BP began a project aimed at understanding acid crude corrosion in the oil refinery at Grangemouth, Scotland. We have carried out significant work using on-line corrosion monitoring techniques, anti-corrosion chemicals, laboratory-based testing of main process streams, and detailed inspection during turnaround times. This smart, integrated approach to risk evaluation and refinery monitoring increased margins at the refinery while maintaining the integrity of the operating plant.