RBI and corrosion sensors
Think of equipment and pipelines as roads, the process media as traffic flow, and corrosion as road surface defects. Traditional approaches often default to simply inspecting every "road" equally; in contrast, the corrosion loop and RBI (Risk-Based Inspection) approaches require first identifying the specific traffic load, potential failure modes, failure locations, and consequences for each road segment, and then allocating limited inspection resources to the areas most likely to reveal problems.
What exactly should corrosion monitoring—or RBI—target? Is the coating failing? What is the average corrosion rate (via ER probes)? Is there erosion-corrosion at elbows, valves, or pumps? Is there uniform or localized thinning, environmental cracking, thermal fatigue, or creep?
Corrosion
A single fractionating tower can span multiple corrosive environments: the bottom section handles high-temperature oil, while the top section deals with sour gas containing water; the overhead circulating oil and the water phase in the reflux drum involve different media, phases, temperatures, and damage mechanisms. Conversely, a single corrosion loop might encompass vessels, heat exchanger shell/tube sides, valves, and connecting piping, provided the conditions and damage mechanisms within the defined boundaries are sufficiently consistent.
Are the primary damage mechanisms the same? High-temperature sulfidation thinning, under-deposit corrosion (e.g., under salts), wet H2S environmental cracking, thermal fatigue, and erosion cannot simply be lumped together under a vague label.
Therefore, different environments and materials require different corrosion monitoring strategies. Probes made of the same material as the equipment should be used to monitor actual operating conditions; this ensures that corrosion monitoring—and the subsequent development of corrosion models based on this data—holds practical value.
Methods such as simple thickness measurement, corrosion scanning, and surface or volumetric NDT (Non-Destructive Testing).
Regarding ER corrosion rates (average corrosion):
Material property monitoring
Is the material the same across the equipment? Carbon steel, low-alloy steel, and austenitic stainless steel may exhibit different sensitivities to the same medium. This necessitates real-time monitoring using probes made of equivalent materials.
Environment
Second question: Are the medium and phase the same? Simply saying "it's all oil and gas" is insufficient; the gas phase, liquid phase, free water, and deposited salts can alter the conditions for damage. Third question: Are the temperature and pressure ranges similar? While average values may be similar, it is also essential to consider factors such as start-stop cycles, tower switching, chemical injection, and anomalous deviations.
Continuous monitoring of the overall environment and corrosivity parameters
Autonomous recording of corrosion rates and environmental severity
Our corrosion monitoring capabilities include:
ER (Electrical Resistance) corrosion rate monitoring: Real-time monitoring of corrosion on matched materials (average corrosion)
Surface conductivity monitoring (monitoring pitting and crevice corrosion)
Measured in the form of current
EIS (Electrochemical Impedance Spectroscopy) analysis
Monitoring of coating degradation
Future capabilities:
Physics-based modeling of coating water absorption and degradation
Advanced coating degradation models
