Sensor Technologies



Track Wall Thinning in Hot Elbows:

The Challenge

Wall thinning occurs in elbows in chemical facilities, power plants, ore processing, and bitumen upgraders because of internal corrosion and erosion. Due to factors including the small inner diameter, complex path, and component shape, in-line inspection ( ILI) of the degraded regions is not generally possible. Periodic measurements using non-destructive examination (NDE) methods, such as ultrasonic scanning, are the only practical alternative. Unfortunately, on hot components at temperatures of 250-300°C, measurement accuracy is often a problem. In addition, many of the elbows are not easily accessible for scanning with hand-held probes. Important information about corrosion growth and wall thinning rates within the elbows can be obtained by more frequently or continuously monitoring degraded areas. This knowledge can help operators extend the life cycle of most components. Since most elbows are remote and access to electrical power may not be available, a compatible monitoring system is required.

Is there a cost-effective sensor system that can operate in a remote environment and monitor wall thinning? Is this system safe to use in a potentially flammable, high temperature environment? Is this system reliable and will the sensors function in the environment? Can the sensor system be accessed by periodic on-site measurements, or in a continuous mode at remote locations?

The Solution

FOX-TEK offers an engineered solution to address these concerns—FT fiber optic sensors. FT sensors are passive, non-electrical and are usually installed on elbows where corrosion/erosion is known to occur. The added cost of installing the sensors in minimal compared to the potential cost of a component failure. Sensor configurations are available for monitoring areas 100 m or more in length, or for localized areas as small as 8 cm diameter. FOX-TEK software determines the wall thinning rate from sensor data collected with an FTI-series monitor. Real-time continuous monitoring or on-site periodic monitoring are options available to the user. The FOX-TEK software is configurable with pre-set wall thickness threshold values that, when reached, activate an e-mail alarm signal that is sent to various personnel.

Summary of Benefits

  • Longer, safer operational lifetime of process elbows
  • Reduced operational downtimes
  • Establish effectiveness of corrosion mitigation
  Cost Savings
  • Maintenance schedules based on real-time operational status
  • Reduced risk of pipe failure and clean-up costs
  • Alarm signals when pipe wall thickness has reached threshold value
  • Reduced risk to personnel due to premature pipe failure
  • Sensors are non-electrical and immune to EMI
  • Reduced risk of pipe failure and loss of contents
  • Reduced risk of contamination of environment by product spills