Distillate Hydroprocessing Unit (DHU)


After replacing piping during a unit re-vamp, slight process changes seemed to cause significant corrosion to an inaccessible location. However, due to the early life of piping (<3 yrs. old) and limited data available, skepticism was raised from customer about the true corrosion rate of the piping. A semi-permanent platform was then built to access to the location and an NDT technician was scheduled to perform a complete UT survey every 6 months.


DHU – Operating Temp ~115F

  • 6” & 8” elbows (SCH 120 & 140)

Product Used

smartPIMS Cellular

  • smartPIMS LT Cellular w/ 6 temporary dual probes (3 probes per elbow)
  • Monitoring interval: 1 reading & transmission per day
  • DSI bolted to handrail


  • Cost savings from scaffolding, ladders, NDE technicians
  • More reliable/better data to develop better corrosion rate trending