Cathodic protection snapshot

Name of technique

Cathodic protection

Use

Prevent corrosion
Complement protection given by coatings

Definition

A technique where an ionic current towards the structure from the electrolyte is used to counter the corrosion current flowing out of the structure.

CP criteria

CP potential of -850 mV vs. CSE
An instant off potential of at least -850 mV vs CSE
A minimum 100 mV polarization post instant off

CP measurement techniques

Soil resistivity
CIPS
DCVG
Line current

Factors affecting CP requirements

pH
velocity
ionic type
ionic concentration
temperature

Issues with CP

Stray current corrosion
Insufficient CP potential
Insufficient CP current
Electrical shorting

I will discuss all these with examples in this major course, where you can prepare for the basics for your certification course!

Check out the introductory video for the brand new course and click on the link to access!

https://corrospective.com/courses/basics-of-cathodic-protection-cp-in-oil-and-gas-industry

Practice your CP knowledge here! Check out Quiz 1!

😀Happy learning!😀

Comments

Corrosion in fertilizer industry - 1.2 Elemental sulphur attack

WATCH THE VIDEO HERE OR READ ON BELOW! Elemental sulphur attack is NOT sulphidation or hydrogen sulphide corrosion. It is an aqueous corrosion phenomenon. It considers two modes - acidification of sulphur - formation of sulphuric acid 2. direct cathodic reduction of sulphur with anodic dissolution of iron The lowering of pH is the main source of corrosion in both the methods. The phenomenon is temperature dependent. It increases with increase in temperature and becomes particularly severe above the melting point of sulphur (~112.8 degree Celsius). Hydrogen sulphide present in the petroleum may aggravate the sulphur attack by enhancing uniform pitting corrosion. Monoethylene glycol is used to prevent condensate formation ans may be present in traces in the feedstock petroleum. This enhances the sulphur attack in the form of uniform corrosion, and crevice corrosion. References: Fang, Haitao, Brown, Bruce, Young, David, and Srdjan Nešic. "Investigation Of Elemental Sulfur Cor

What is a Corrosion Loop - PART 1 - CONCEPT

Corrosion loop is used to simplify inspection procedures in refining processes. Corrosion loop is defined as a group of components with common materials, processes, and operating parameters. Source: Rachman, A. and Ratnayake, R.M.C. (2020), "Corrosion loop development of oil and gas piping system based on machine learning and group technology method", Journal of Quality in Maintenance Engineering, Vol. 26 No. 3, pp. 349-368. https://doi.org/10.1108/JQME-07-2018-0058 It is needed when the scenario has - 1. Complex process 2. Several variables such a materials of construction, process parameters, functions 3. Multiple damage mechanisms WATCH THE VIDEO FOR A DETAILED EXPLANATION - Click here for part 2 ! https://corrospective.com/ 😀Happy learning! 😀

Corrosion in daily life - Steel frames on a balcony

Corrosion in daily life - Steel frames Looking at LinkedIn, corrosion may feel like an extremely intricate issue seen in large industries. However, looking around, we can see corrosion everywhere! Where was this photo taken? The photo above is of a steel frame attached to a balcony. The part shown here is the bottom part of the frame. The coatings for such steel parts usually serve the purpose of moderate corrosion protection and more of aesthetics. If you observe, the thickness of the coatings also does not seem to be a lot. Why did the coating degrade? When it rains, the rainwater collects on the bottom of the frames. This degrades the coating. At the places where it is not perfect anyway, the underlying steel is free to corrode. Most importantly, corrosion is more severe at the edges. It is severe enough to chip off the material entirely. That point is a prime site for crack formation and breaking of the frame. Have you seen such corrosion in your balcony frame? Let me

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