Case Studies

TRACERCO Diagnostics™ Scan

Pipe Study

Pipeline Scale and Blockages Located
During a routine refinery shutdown, the knockout pot on the header system to the flare line was found to contain scale and corrosion products. The possibility of significant build-up of sections of the line worried engineers. If deposits were present these should be attended to during the shutdown. Normally, this plant would use X-ray analysis to selectively look at areas of pipework. This procedure is tedious and can prove expensive, since each shot is only able to ‘see’ a few feet at a time. A more thorough survey was needed; so Tracerco was called in to gamma ray scan the critical lengths of pipe and around all of the bends. Gamma ray scanning is a quick, portable technique, which can locate areas of build-up inside pipes as the scan is being made. By taking a measurement on a clean piece of identical pipe, a reference point is obtained from which assumptions regarding the amount of build up can be made.

Once the equipment was set-up, the key areas along the 2-mile length of pipe were examined within a few hours. Build-up usually occurs at bends in the pipeline, because the reduced velocity around the bend encourages deposition. In this particular refinery, Tracerco identified some 20 areas where there was significant build up including 5 spots at low points in bends, which needed urgent attention. Upon entry into the pipe, the extent of build-up in these areas was confirmed. This also provided reference data to more accurately assess the extent of build-up elsewhere. Periodical monitoring of these areas of concern allowed maintenance work to be scheduled in advance, as and when appreciable build-up occurred.

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