2 replies to this topic

[Neelakantan]

hi friends,
a condensate stabilisation tower (roughly 3.8 m dia) in offshore fixed platform is found to be not delivering the required duty. As train shut down is not available long enough for depressuring, draining, deHC and O2 quality for man entry, it is proposed to take xrays at suspect trays to see the conditions of the internals.

is it feasible to do so? is x-ray the best option or some ultrasonic mapping can be done? any pointers and references to qualified or experienced parties would be really appreciated

regards
neelakantan

[gvdlans]

Reference: Henry Z. Kister, Distillation Operation, Chapter 14.

Gamma-ray scanning can a.o. be used to diagnose the following abnormalities:
- damaged trays
- missing trays
- collapsed trays
- flooded trays
- rate of flooding of a tray
- foaming
- dry tray panels
- collapsed packed beds

X rays have limited process troubleshooting applications in distillation columns. They are sometimes used to detect blockages, up-ended trays and some types of mechanical damage.

[Zauberberg]

Before attempting to do any kind of scanning in remote locations, troubleshoot the tower operation with available tools you have: DCS and local instruments. Unless there is some really weird kind of problem, you should be able to at least pinpoint the main cause(s) of tower underperformance. You haven't told us what is the actual problem in tower operation, and how it manifests itself.

A reliable party for performing gamma scans is Tru-Tec, having references on a worldwide scale. But that should be your last solution - once when you exhaust all the field methods.

Good luck,