From April 19-30 2021, MetriCorr is attending the virtual conference & expo CORROSION
CORROSION Virtual, the world’s largest conference and exposition that unites different corrosion industries across the world is going virtual for the first time, and we are attending as exhibitors. This virtual conference gives you the opportunity to interact with experts such as MetriCorr as we come together to focus on the methods for identifying, preventing, and combating corrosion problems across all major industries. Below you will find descriptions of the events where Dr. Junker Olesen and Dr. Vendelbo Nielsen will present:
- Part A: Their findings on AC Corrosion field testing and commissioning of AC mitigation and monitoring, and
- Part B: A separate paper of the laboratory test using electrical resistance (ER) probes on different CP levels.
- Dr. Junker Olesen on AC Corrosion of cathodically protected pipelines – a summary
AC Corrosion At Other Frequencies Part A: Field Investigation And Mitigation
30. April 9-9:25 AM (MT) / 4-4:25 PM (CET)
A 2018 field investigation on an NPS 6, approximately 4 km long, liquid pipeline, identified a rectifier as the likely source of the elevated DC and AC current densities, which resulted in AC corrosion anomalies detected during in-line inspections (ILI). The findings of this case study, presented in the NACE Corrosion 2019 Paper No. 13188, indicated that the 120 Hz rectifier ripple may have contributed to the accelerated AC corrosion at this location.
This follow-up paper is Part A of a two-part further investigation into corrosion rates on cathodically protected structures due to AC frequencies other than the fundamental power frequencies of 50 Hz and 60 Hz. Part A involves additional field testing on the subject pipeline, and commissioning of the recommended AC mitigation and monitoring systems. Part B of this investigation will be presented in a separate paper and will discuss the results of laboratory test.
AC Corrosion at Other Frequencies Part B: Laboratory Investigations
30. April 9:30-9:55 AM (MT) / 4:30-4:55 PM (CET)
AC corrosion on cathodically protected pipelines is commonly experienced due to inference from high voltage transmission lines at a frequency of 50 or 60 Hz. In some cases, the source of interference may be low frequency AC transit systems (1/3 of the fundamental frequency) and in other cases higher harmonics of the fundamental frequency can be detected on pipelines. In part A of this paper a field investigation of a 120 Hz rectifier ripple, suspected to lead to AC corrosion, is investigated.
In this part B of the present investigation, AC corrosion of cathodically protected steel is investigated using electrical resistance (ER) probes at various frequencies and different CP levels in an artificial soil solution. The effect of frequency on basic aspects and understanding of AC corrosion, specifically in terms of alkalization mechanisms and related time constants for involved processes, is discussed.
AC Corrosion of Cathodically Protected Pipelines – Summary
30. April 10-10:25 AM (MT) / 5-5:25 PM (CET)
This paper presents a summary of the results obtained during 3 years of PhD studies between the Technical University of Denmark and MetriCorr, finalised in October 2018 and defended in January 2019. Amongst the findings are:
- an improved understanding of AC corrosion as different corrosion phenomena at low and high levels of cathodic protection respectively,
- an enhanced understanding of the reactions in soil systems that lead to establishment of corrosive environments,
- discovery of a close correlation between current density criteria and the Pourbaix diagram,
- improved understanding of the influence of the CP level on the formation of passive films and the electrochemical double-layer characteristics,
- and presentation of a new model for AC corrosion that considers ionic dissolution and hydrogen evolution in the passive film destabilization mechanism.
The results are discussed in relation to literature and relevant cathodic protection and AC interference standards.
Below you will find our CORROSION2021 YouTube Playlist we have made for CORROSION Virtual. Videos include:
- Kick-Off video – providing overview of our booth
- ICL product presentation
- ICL-C product presentation
- VL100 product presentation
- Test Station Commissioning
