Sulfur and Naphthenic Acid Interactions in a Snapshot of Refinery Distillates

Abstract Sulfur organic compounds contained in crude oils create significant material damage when such oils are processed at high temperatures in distilling towers. These sulfur corrosive damages are enhanced when naphthenic acids are also present in the processed oils. Therefore, the destructive corrosive effects of sulfur compounds and naphthenic acids have to be controlled, mitigated, and estimated/predicted to operate safely the distilling units of oil refineries. A snapshot of refinery distillates was evaluated as part of the experimental work using a specific experimental protocol “pretreatment - challenge” designed to estimate the combined corrosive effects of naphthenic acids and sulfur compounds in oil. This protocol estimates the corrosive processes by evaluating the protectiveness of scales preformed (“pretreatment”) in oil fractions on metal samples against naphthenic acid corrosive attack (“challenge”). The study also investigated the possible connections between fractions corrosivity, and the hydrogen sulfide generated during their experimental evaluation. The refinery distillates selected for this evaluation were obtained from the same oil and were collected from the same vacuum distilling unit over several days. The distilling tower was operated as pulling Light Vacuum Gas Oil (LVGO), 100N, 325N, and High Vacuum Gas Oil (HVGO) streams that were blended back together as “gas oil”.