Ali: Desalting reduces acids from acid-forming soluble salts. Caustic is also sometimes added. The above will not neutralize naphthenic acids. Hope this helps! David Hendrix The Hendrix Group Inc.

Naphtenic acid is the generic name to define all organic acid contained in the Crude. The majority of these acid are known by the chemical formula R (CH2) nCOOH where R, is a ciclopentano ring and n, is typically bigger that 12. However, a multiplicity of other organic acid composites are also present in crude oil and until to date nor all had been analysed. Typical Naphtenic Crudes come from: California, Venezuela, North Sea, west Africa, India, China, Russia. TEMPERATURE Naphtenic corrosion occurs at temperatures between 200%C2ºC and 400%C2ºC. CONDITIONS FOR the OCCURRENCE OF (NAC) In general, the conditions that promote the occurrence of Naphtenic corrosion are: TAN, temperature, metallurgy of the equipment and velocity of the flow and presence of H2S. TAN (Total Acid Number) As general rule when the TAN of the feed is less than 0.5mg KOH/g Naphtenic corrosion will not be expected. If the rate of sulphur in crude is too much low or either less than 0,2% in weight, there is a strong probability of Naphtenic corrosion occurrence. In this last case, number TAN of crudes to process, between the feed and the cuts, will have to be placed between 0.3 and 1.0. The methods of Mitigation of Naphtenic corrosion are; make blending of the crude mix in order to lower n%C2º TAN of the feed, injection of phosphorous inhibitors and make "upgrade" of known resistant alloys %E2%80%9Cimmune%E2%80%9D to naphtenic corrosion such austenitic 317L.