Corrosion inhihitors in petroleum production - effect of water salinity and content

In the present paper, the effect of water/oil ratio and water salinity on the efficiency of some corrosion inhibitors used in petroleum production has been investigated. Tests have been conducted on mild steel in stagnant and dynamic environments. The results revealed that the two parameters generally affect the performance of the inhibitors. The inhibition action increases with the increase of water salinity and oil/water ratio. The extent of these variations depends on the; type of inhibitor. The required Jose in most cases decreases with the increase of water salinity and oil/water ratio. These results indicate that the fluid characteristics must be carefully considered in the evaluation and selection of corrosion inhibitors

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

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

Corrosion inhibition of 304 stainless steel in H3PO4 / Cl-Solutions by the anions of Cr, Mo, N, W, and B III Synergistic effect of anions

The beneficial action of the alloying elements Cr, Mo, W, N, B and Cu on the corrosion resistance of stainless steel has been attributed to the formation of protective passive surface film containing these elements. A study on the formation of such passive film with the help of oxyanions of the alloying elements has been undertaken. Chromate, molybdate, tungstate, nitrite and nitrate anions improve the corrosion resistance of 304 stainless steel in H3PO4/Cl- solution. NO-2/Cr2O72- and MoO42- are more effective in retarding the active corrosion, while the nitrogen species [NO2-, NO3-] are the most effective for pitting attack. The effect of binary and tertiary mixtures of these oxyanions has been examined. Some mixtures afford considerable protection for both active and pitting corrosion. In their presence, the corrosion resistance of the simple 304 steel may be compared with that of more expensive highly alloyed grades