Corrosion inhibitor formulations from coal - tar distillation products for acid cleaning of steel in HCI

ABSTRACT

The chemical cleaning of boilers, heat exchangers, vessels, reactors, piping and other equipments from deposits and scales is usually conducted in acid solutions. Effective corrosion inhibitors are added to avoid the acid attack on metallic surface. The employed inhibitors in this field are based mainly on organic molecules containing nitrogen, sulfur and/or phosphorus. In this paper, inhibitor formulations prepared from coal-tar distillation products namely Anthracene Oil [AO] were evaluated for application in acid cleaning processes using weight loss and polarization measurements. These industrial byproducts contain large number of the above needed molecules. Some of the prepared formulations could offer high inhibition action [about 98%]. The effect of immersion time and temperature revealed quite stability of the inhibitors. Polarization data indicate general adsorption of the additives, affecting both the anodic and cathodic reactions of the metal corrosion