Stevenson, Tim; Ionix Advanced Technologies; United Kingdom
Martin, D.; Ionix Advanced Technologies ltd.; United Kingdom
Mills, R.S.; Ionix Advanced Technologies ltd.; United Kingdom
Wang, C.; Ionix Advanced Technologies ltd.; United Kingdom
Wines, T.I.; Ionix Advanced Technologies ltd.; United Kingdom
Stevenson, T.J.; Ionix Advanced Technologies ltd.; United Kingdom
Effective continuous monitoring of asset integrity subject to corrosion and erosion while minimizing the exposure of personnel to hazardous working environments has always been a major problem in many industries . One solution to this problem is to permanently install non-destructive monitoring equipment, which can continuously provide information on rates of corrosion, cracking or other defects, even in the most severe environments. Achieving this at temperatures approaching 600 ⁰C, under insulation and without the need for transducer cooling, the need for costly shutdown and risk to personnel during inspection of existing plant is prevented.
In refining for example, carbon steel pipe assets are prone to high-temperature corrosion mechanisms due to sulfidation, napthenic acid and erosion mechanisms above 200°C, but are not readily monitored in commercial refineries due to low reliability of present methods.
Current offerings for ultrasonic condition monitoring of high-temperature pipe assets, are limited by transducer operating temperatures through thermal expansion mismatch and low sensitivity [2,3] as well as inefficiencies due to variability in acoustic coupling [4,5,6], large mounting fixtures , in-service calibration and environmental compensation  for reliable and repeatable measurements.
Here, a permanently installed ultrasonic thickness monitoring probe based on the HotSenseTM ultrasonic platform  is employed in a series of case studies to highlight the challenges around the application of ultrasonic monitoring technology for in-service inspection of these assets. Wall loss data captured for a range of insulated sch40 carbon steel pipes 3-12″ diameter are presented. Using standard pipe preparation techniques for ultrasonic thickness monitoring, at 400°C over 3 months, the solutions and limitations are reported for;
” Mounting – mechanical fixtures to mixed geometry pipe work, incl. elbows
” Coupling – liquid, solid and dry
” Calibration – initial and in-service calibration methods
” Temperature compensation from -75to+400°C
” Monitoring up to 550°C permanently.