Definition - What does Naphthenic Acid mean?
Naphthenic acid refers to a chemical substance that is composed of several cyclopentyl and cyclohexyl carboxylic acids with many large carbon chains. It is often used in the synthesis of metals and promotes corrosion in high-velocity areas and vessels for petroleum applications.
Corrosionpedia explains Naphthenic Acid
Naphthenic acid is industrially sourced by extraction from kerosene and diesel petroleum fractions. Typically, these acids are considered to be waste or byproduct streams. Naphthenic acid is primarily used as a key component to produce oil-soluble metal soaps for driers and other catalysts as well as amine for corrosion inhibitors.
Naphthenic acid corrosion (NAC) occurs mostly in the crude oil fractional distillation process in the 220°C to 400°C (428°F to 752°F) temperature range. Temperatures higher than this range typically exhibit minimal corrosion due to the decomposition of naphthenic acids. NAC can be diminished by sulfur-containing compounds present in petroleum in the form of soluble sulfides. Petroleum that contains higher concentrations of naphthenic acids are often characterized by a high total acid number (TAN).