Influence of an oil soluble inhibitor on microbiologically influenced corrosion in a diesel transporting pipeline

Abstract

Microbial degradation of the oil soluble corrosion inhibitor (OSCI) Baker NC 351 contributed to a decrease in inhibitor efficiency. Corrosion inhibition efficiency was studied by the rotating cage and flow loop methods. The nature of the biodegradation of the corrosion inhibitor was also analysed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. The influence of bacterial activity on the degradation of the corrosion inhibitor and its influence on corrosion of API 5LX were evaluated using a weight loss technique and impedance studies. Serratia marcescens ACE2 and Bacillus cereus ACE4 can degrade aromatic and aliphatic hydrocarbons present in the corrosion inhibitor. The present study also discusses the demerits of the oil soluble corrosion inhibitors used in petroleum product pipeline.

Keywords:

• Diesel pipeline
• oil soluble corrosion inhibitor (OSCI)
• rotating cage method
• flow loop method
• biodegradation
• microbiologically influenced corrosion

Acknowledgements

The authors wish to express their thanks to the Director, CECRI, Karaikudi-6 for his kind permission to publish these results. One of the authors, N. Muthukumar, thanks CSIR for the award of a Senior Research Fellowship. The authors also thank Mr A. Rajasekar, SRF and Prof. S. Karuthapandian, Head of the Biotechnology Department, Alagappa University, Karaikudi for providing the identified bacterial species and are grateful to Dr S. Sathiyanarayanan for his kind help with the electrochemical techniques.