Monitoring Technologies on Knowledge Library

Corrosion coupons

Mon, 01 Jan 0001 00:00:00 +0000

General Info

The exposure of corrosion coupons is one of the oldest techniques for corrosion monitoring and, despite several drawbacks, it remains popular and widely used in various applications.

In the refining industry, coupons are mostly used in cooling water systems and overhead (OVHD) systems in crude distillation. Sometime they can also be used in amine units (various locations on rich and lean amine and regenerator OVHD), sour water (SW) strippers (mostly stripper OVHD), and other applications where multiphase, condensing systems with potential for deposition are encountered.

Electrical resistance (ER)

Mon, 01 Jan 0001 00:00:00 +0000

General Info

Electrical Resistance (ER), along with corrosion coupons, is one of the oldest industrial corrosion monitoring techniques. However, the popularity of ER systems has diminished over the last decades in favor of non-intrusive, online ultrasonic thickness monitoring (UT). Nevertheless, ER still possesses certain advantages and, when used properly, can provide accurate and reliable information about process stream corrosivity.

Installation

Similar to LPR, the retractable system is also the most popular solution for installing ER probes in refining environments. The recommended mounting system consists a flange connection (see Figure 1). Threaded probe mounting, often using a 1" NPT nozzle, is not always recommended, as vibrations from process pipes or equipment can loosen the threaded connection .

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Linear Polarization Resistance (LPR)

Mon, 01 Jan 0001 00:00:00 +0000

General Info

Linear Polarization Resistance (LPR) is a technique that provides near real-time corrosion measurements. Modern LPR technologies, which often incorporate additional electrochemical techniques (e.g., Harmonic Distortion Analysis or Electrochemical Noise) within a single instrument, can provide accurate monitoring not only in traditionally LPR-applicable systems like cooling water but also in more challenging environments such as sour water, lean amine, and even condensing overhead (OVHD). These modern LPR systems allow for measurement intervals as short as minutes, making it well-suited for online process-corrosion correlation.