Inhibition of Calcium Naphthenate. Experimental Methods to Study the Effect of Commercially Available Naphthenate Inhibitors

Abstract

In this study, different methods have been developed for studying naphthenate inhibitors. One first method is based on interfacial activity of systems with naphthenic acids, inhibitors, and calcium viewing reaction mechanisms at interfaces of the inhibitors. A second method is based on gravimetrical determination of interfacial layer in a two phase system and gives a thermodynamic approach to naphthenate formation, and a third method utilizes a ultraviolet-active model tetraacid to directly determine the depletion in bulk phase concentration during a two-phase reaction. The results indicate that inhibitors may act through several mechanisms, and depending on the total system different mechanisms may have the highest efficiency also by combining several mechanisms.

Keywords:

• Calcium
• inhibitors
• interfacial activity
• interfacial film
• naphthenate

Acknowledgments

The authors would like to acknowledge Statoil ASA and the Norwegian Academy of Science and Letters for financial support through the VISTA program, and the Research Council of Norway through the PETROMAKS program. Acknowledgments are extended to the JIP consortium, consisting of AkzoNobel, Baker Petrolite, BP, Champion Technologies, Chevron, Clariant Oil Services, ConocoPhillips, Shell Global Solutions, Statoil ASA, Talisman Energy and Total. A special thanks is offered to the chemical vendors for supplying naphthenate inhibitors. Finally, Heléne Magnusson is thanked for valuable discussions.