case study 10 high temperature pipes web lrut
DESCRIPTION
LRUTTRANSCRIPT
17 Doverbeck Close
Ravenshead
Nottingham NG15 9ER
Tel 4 (0) 1623 491093
Fax 44 (0) 1623 491093
www.guided-ultrasonics.com
The Wavemaker Pipe Screening System (WPSS) is capable of screening pipes at elevated temperatures. Using special procedures pipes of up to 180
oC (360F)
have been successfully screened with our standard equipment. If the pipe wall temperature is below 70
oC (160F) no
special precautions need to be taken and inspection can continue as normal.
This case study presents the result obtained from the test location shown in the photograph opposite. The pipe was a 24" diameter crude line with an operating temperature of 150
oC (300F). The pipe was
of great concern to the client as there had been an isolated leak which was repaired using a clamp (visible in the photograph just before the test location). The purpose of the guided wave inspection was to determine the extent of the corrosion to allow the client to plan the maintenance work.
Pipes in service often operate at elevated temperatures. In most cases it is not possible for the pipework to be taken out of service to allow inspection to be carried out. Traditionally all inspection work is carried out during planned shutdown periods where entire sections of the plant are taken off line.
This case study has demonstrated the capability of the WPSS to inspect pipes at elevated temperatures. Inspection can be carried out on line with minimal disruption to insulation or coatings on the pipe. Problem areas can be identified and follow up testing using a complimentary NDT technique carried out. Additionally, the WPSS can be used to monitor the condition of known defects between planned maintenance shutdowns. The WPSS provides a very cost effective solution to the screening and monitoring of pipes at elevated temperatures.
-4.0 -2.0 0.0 2.0 4.0 6.0 8.0 10.0Distance (m)
Am
(L
ne
r)
+F
2
+F
3
+F
4
+F
5
+F
6
-F2
10.0
Test Location
The result obtained using the WPSS is shown above. The positions of welds, vents and bend are marked on the schematic diagram above the trace. The position of the repair clamp is labelled +F2. The large amplitude non-symmetric signals which are detected within the first 2m of the trace on both sides of the ring indicates severe distributed corrosion over this section of the pipe. The wall loss was later verified to be up to 50%.