Principles for selecting corrosion/abrasion monitoring points on in-service process pipelines
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Process pipelines, especially those involving medium particles and high-pressure systems with H2S-containing media, should generally undergo periodic inspections for corrosion and abrasion, such as inspections using UT or X-Ray methods once a year. It would definitely be foolish and unrealistic to remove all the pipelines for a thorough inspection. Generally, it is necessary to select several specific points on the pipeline for monitoring. What I would like to know is, where are these monitoring sites usually located? Are there any standards for reference? Furthermore, how is insulation and corrosion protection typically handled on the outside of pipelines?
Generally, the elbow area is inspected. We don’t have any special methods for insulation.
Common methods for online corrosion monitoring include online thickness measurement, corrosion probes, and corrosion coupons. The principles for setting these parameters take into account factors such as the corrosiveness of the process medium, temperature, pressure, material quality, and safety performance
For pipelines at risk of wear, attention is generally paid to areas where there are changes in the medium flow rate or flow pattern, such as elbows, tees, valves, and three-way connections, as well as the pipelines adjacent to these areas. For pipelines containing H2S, it is necessary to check whether there is a wet hydrogen sulfide stress corrosion environment within the pipeline; if so, attention should be paid to the areas in the pipeline where stress exists.