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New field-proven automated electrochemical monitoring technology provides a means for evaluating corrosion and pitting in petroleum piping, making corrosion a real-time process variable. A broad range of environments has been studied, including vapor phase (e.g., dehydrated gas), multiphase (oil, gas, and water), and low-to-high water cut.
The data demonstrate the value of the technology in alerting operators online, real time to the corrosion effects resulting from the varying conditions commonly found in production systems, gathering lines, pipelines, and facilities.
One problem associated with corrosion control is that corrosion is commonly dealt with in a historical sense, after the damage has occurred, and with no opportunity to prevent recurrence. Corrosion measurements usually are reactive maintenance functions.
Offline monitoring data can neither be viewed real time nor viewed alongside the process conditions that often initiate corrosion. Recent innovations in monitoring technology, however, enable the corrosion engineer to interact directly with the new online, real-time world of process control optimization and asset management.
Improved communications also provide online connectivity for corrosion engineers, bringing them closer to the frontline people who control processes and manage facilities.
Under this new paradigm, the corrosion measurement device becomes the "tachometer" for the facility, showing real time when processes go awry, prompting remedial action before substantial damage occurs. Reduced corrosion-related damage, failures, and outages have increased runtime.
Offline measurement
Corrosion measurement methods currently in use-including simple off-line techniques such as weight-loss analysis-only provide a retrospective status check rather than a means of active, real-time process control.
Offline measurement methods also include such general corrosion measurement techniques as electrical resistance and linear polarization resistance. These systems operate in standalone mode, providing spot corrosion data via battery powered, field-mounted instruments often with logging capability.
Such systems are flexible in that they can be installed remotely. But this flexibility is offset by the fact that data are available only periodically and requires personnel to manually download and process the data. Furthermore, such systems often are limited by shrinking allocations for corrosion control in tightening maintenance budgets.
Once gathered, postprocessing of the corrosion data is often performed in a computerized spreadsheet. In most of these cases, the data are viewed after the corrosion has occurred and analysis cannot easily take into account process variables (e.g., temperature, pressure,...