The monitoring of galvanic corrosion behaviour caused by mineral deposit in pipeline working conditions using ring form electronic resistance sensor system

Abstract

In this paper, a ring form electronic resistance (ER) sensor system was developed for the study of under-deposit corrosion (UDC) caused by mineral deposit in pipeline conditions. The corrosion status of different locations along the pipeline circle direction and the galvanic current between the deposit-covered area and the bare steel area were monitored by the conjunction of the ER method and electrochemical noise technique. The performance of inhibitor ethylene diamine tetra methylene phosphonic acid sodium (EDTMPS) on UDC was studied by both the electrochemical method and the ring form ER sensor system. The measurement results demonstrated that the inhomogeneous distribution of the rust layer will cause heterogeneous corrosion patterns in the pipeline. Though EDTMPS showed an excellent inhibition effect for the corrosion of both deposit-covered steel and bare steel in electrochemical tests, it failed for the inhibition of UDC in the pipeline working conditions and serious localised corrosion beneath the sand particle was monitored by the sensor system.

Keywords:

• Ring form ER sensor
• Galvanic corrosion
• Inhibitor
• Mineral deposit
• Electrochemical noise

Additional information

Funding

This research was sponsored by Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period of China: The subtask of the Oil & Gas Exploitation of South China Sea Demonstration Project: Corrosion Monitoring and Design of Cathodic Protection System for LW3-1 gas field (No. 2011ZX05056), Chinese National Science Foundation (11201023) and Fundamental Research Funds for the Central Universities in China (DUT15YQ36).