Gamma scanning seeks an inside edge

Many companies decide not to build up certain capabilities in-house mainly because they don’t have sufficient regular demand for them. Gamma scanning of distillation columns is a case in point, but on-site scanning specialists may be the wave of the future.

By Mike Spear, editor at large

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Recent developments in scanning technologies, however, have made it somewhat easier for the non-expert. “Some of these advances,” says Gledhill, “have been more in the presentation of results, with improved computer graphics and so on, to make them easier to comprehend for someone who isn’t looking at scans every day.”

Quantum is developing software that will automatically read some scans. “This auto-interpretation software will pick out the ‘low-hanging fruit,’ the easy calls,” says Winfield, “and shorten the time for training new engineers. We have a couple of beta versions that may be rolled out in a couple of months.”

Permanent fix

Tracerco meanwhile has been developing an alternative to conventional tower scanning. In contrast to the usual approach of setting up the source and detector systems each time a scan is required, its Diagnostics RapidScan system is permanently installed on a column to provide process engineers with the option of online repeat scans or scanning multiple times at different rates to evaluate mechanical-, rate- or process-related problems. The approach affords all the capabilities of conventional tower scanning and may improve the ability to diagnose more subtle process changes by stringently controlling and eliminating variability in scan-line orientations and paths, the company claims.

Combining a wireless detection system with an easy-to-install permanent scanning guidewire system, the RapidScan technology eliminates the costs of building scaffolding or renting cranes for columns with limited or no ladder or platform access. All scanning operations are performed from ground level with no need to climb the tower (Figure 1).

Figure 1. The RapidScan system allows engineers to run scans from the ground level, eliminating the need to climb towers.
Figure 1. The RapidScan system allows engineers to run scans from the ground level, eliminating the need to climb towers.

The stainless-steel pulleys and brackets required for the source and detector are affixed to the existing structure using insulation bands; no welding or direct attachment to the column walls is necessary.

Having the scanning infrastructure permanently in place offers an additional benefit — reduced time to conduct a scan, which in turn lessens the burden on plant operators to hold the column at set conditions while scanning, says Tracerco.

The future

While a development like RapidScan will enable columns to be scanned much more easily and frequently than before, it will not necessarily overcome operating companies’ traditional resistance to having dedicated specialists on-site. However, several scanning-service providers are promoting the benefits of establishing permanent teams. “I’ve tried to argue with some plants that they would be better off with someone there permanently,” says Fox. “That way you can eliminate the unknowns, do away with the guessing that goes on before a company decides to call for a scan.”

Winfield also thinks dedicated on-site scanning crews could be the wave of the future. “Service companies can come up with some pretty innovative ways of pricing,” he says. “I’ve approached several companies with large complexes that could justify a dedicated team between them. They could be integrated with the plant, attending morning meetings and so on. You could price that on, say, a base fee plus whatever savings we generate.”

Figure 2. Multi-year contract provides permanent on-site team to handle a variety of maintenance jobs such as pressurized leak sealing.
Figure 2. Multi-year contract provides permanent on-site team to handle a variety of maintenance jobs such as pressurized leak sealing.

This approach has certainly proven extremely successful for a service company and its clients in a different, though equally important, area of plant operation. Perhaps better known for its leak-sealing service (Figure 2), Furmanite, LaPorte, Texas, and Kendal, U.K., provides online valve testing and repair, in-situ machining, controlled bolting and pressure systems integrity management, composite repair and hot tapping pipeline interventions. Normally, operating companies call in its teams to tackle problems on a reactive basis — often to tide a plant over until scheduled shutdowns.

Last year, however, Furmanite signed a five-year contract with Shell to provide a permanent on-site core team at the oil giant’s Stanlow, U.K., complex, one of Europe’s largest refineries. “Shell not only gains unrestricted access to our services and a rapid response engineering resource… but also a proactive team able to monitor and recommend, as well as undertake repair and maintenance work as required,” says business development manager Mike Tucker.

To counter Shell’s initial reluctance, Furmanite proposed “very keen KPIs [key performance indicators] to monitor the non-productive time of the on-site team,” Tucker explains, “so they’re not going to be sitting around waiting for things to go wrong. It’s a transparent process. By being on-site and having an intimate knowledge of the real issues, we can tailor the solution to suit the requirements; nothing more, nothing less.”

So successful has this “outside in, outsourcing” approach been for both companies — Tucker says in some cases Shell has experienced an 80% cost saving by “treating the patient when it’s only sneezing” — that Furmanite now has similar contracts on other refineries and petrochemical complexes run by the likes of BP, Ineos, Innovene and ConocoPhillips, as well as for British Energy’s nuclear power stations.

Echoing Fox, Tucker says: “It takes away the unknown factor, and it’s the unknown factor that ends up costing money.” And, as customers of scanning companies know only too well, investing a few thousand dollars in their services can save millions in avoiding unplanned shutdowns.

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