Protecting metal walls of refinery units from corrosion by naphthenic acids in crude oil or distillation fractions, involves adding a thiol-substituted carboxylic acid or derivative, e.g. thioglycolic acid, to the hydrocarbon feed stream

摘要

Thiol-substituted carboxylic acids or their derivatives are used as feed additives for protecting the metal walls of refinery units from corrosion by naphthenic acids . A method for protecting the metal walls of a refinery unit from corrosion by naphthenic acids involves adding a compound of formula (I) to the hydrocarbon feed stream. HS-B-COOR (I) B : 1-18C (preferably 1-4C) saturated hydrocarbylene (linear, branched or cyclic); and R : H, alkali or alkaline earth metal, ammonium, or 1-18C (preferably 1-10C) alkyl, cycloalkyl, aryl, alkylaryl or aralkyl (all optionally containing one or more heteroatoms).