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PRCI PR-186-9918
- Hot Spot Protection for Impressed Current Systems
- Report / Survey by Pipeline Research Council International, 09/01/2003
- Publisher: PRCI
$198.00$395.00
L52100e
CC Technologies Laboratories Inc.
Need: As pipeline coating and associated cathodic protection (CP) systems age, areas along the pipeline inevitably develop that fall below a prescribed CP criterion. In efforts to meet an adequate CP criterion, engineers often resort to supplementing their existing CP system with magnesium anodes at these "low" potential areas resulting in a "hybrid" cathodic protection system consisting of an impressed current CP system (ICCP) supplemented with magnesium (Mg) anodes. This often achieves the desired result i.e. the potential measured over the pipe becomes more negative. However, there remain several unanswered questions concerning the real benefits to the polarization level of the pipe and the overall effect on the impressed current cathodic protection system.
Result: The primary objective of this PRCI project was to develop a better understanding of the relationship between ICCP systems and Mg anodes installed as hot-spot protection. This understanding will assist CP engineers in the design and operation of effective, economic CP systems.
Benefit: The approach to this project was to utilize a combination of laboratory and full scale test pipe under well controlled and quantifiable conditions to answer specific questions about hot-spot anode performance, combined with measurements on operating pipelines to verify performance in the field. Operating pipelines were selected with coupon test stations (CTS, monitoring based on the PRCI design) installed to permit quantitative measurements of CP current densities to simulated holidays (coupons) and accurate measurements of polarized potentials with and without hot-spot anodes added.
CC Technologies Laboratories Inc.
Need: As pipeline coating and associated cathodic protection (CP) systems age, areas along the pipeline inevitably develop that fall below a prescribed CP criterion. In efforts to meet an adequate CP criterion, engineers often resort to supplementing their existing CP system with magnesium anodes at these "low" potential areas resulting in a "hybrid" cathodic protection system consisting of an impressed current CP system (ICCP) supplemented with magnesium (Mg) anodes. This often achieves the desired result i.e. the potential measured over the pipe becomes more negative. However, there remain several unanswered questions concerning the real benefits to the polarization level of the pipe and the overall effect on the impressed current cathodic protection system.
Result: The primary objective of this PRCI project was to develop a better understanding of the relationship between ICCP systems and Mg anodes installed as hot-spot protection. This understanding will assist CP engineers in the design and operation of effective, economic CP systems.
Benefit: The approach to this project was to utilize a combination of laboratory and full scale test pipe under well controlled and quantifiable conditions to answer specific questions about hot-spot anode performance, combined with measurements on operating pipelines to verify performance in the field. Operating pipelines were selected with coupon test stations (CTS, monitoring based on the PRCI design) installed to permit quantitative measurements of CP current densities to simulated holidays (coupons) and accurate measurements of polarized potentials with and without hot-spot anodes added.
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