Keeping Shell out of the heat

Edited by the Engineeringtalk editorial team May 8, 2002

Out-sourced thermography consultancy has been used successfully to identify potential problem areas on three furnaces at Shell's Stanlow Refinery.

Out-sourced thermography consultancy has been used successfully to identify potential problem areas on three furnaces at Shell's Stanlow Refinery.

The subsequent repairs, carried out during a routine shutdown cost around GBP 50,000 but it has been estimated that the cost of lost revenue could have been almost 30 times this amount if unplanned downtime had been necessary as a result of failure.

Todays processing industries are endeavouring to minimise routine maintenance whilst still ensuring that safety and production capabilities are not jeopardised in any way.

Companies like Shell are discovering that outsourcing critical expertise offers a highly efficient and cost effective method of providing effective data for the planning of preventative maintenance.

It is well known that thermography techniques provide a highly efficient method of identifying problems across a broad range of process and control equipment.

Thermographic surveys play an important part in Shell's ongoing condition monitoring programme at the Stanlow Refinery, and have proved to be an invaluable tool.

Stockport based AV Technology (AVT) specialises in predictive maintenance for both static and rotating equipment.

Chris Greenhalgh, AVT's General Manager, is clear about the role his company plays in providing an effective service to industry: "Our success comes from the use of the latest equipment and hard won experience, together with the ability to analyse the results quickly and effectively.

The analysis gives our customers the confidence to carry out any remedial work in a controlled manner.

This allows them to strike a balance between a ' belt and braces' approach to maintenance which often leads to unnecessary repairs and one where vital repairs may be postponed, resulting in the high costs associated with unscheduled downtime".

AVT have worked closely with Shell for over three years and have recently conducted an in-depth survey on three furnaces at their Stanlow refinery in Cheshire.

The examination was commissioned to confirm the condition of ductings, expansion joints and inspection doors, prior to a planned two week shut down.

Results from the analysis highlighted a number of areas where remedial action was needed, with failure prediction varying from immediate to 12 months.

Of particular concern was the heat pattern around a temporary box section welded on the side of one of the furnaces.

The preliminary recommendation was to replace the box section but further inspection clearly showed that the refractory linings on the furnace wall were unstable.

This information allowed Shell to revise the safe system of work for entry and specify appropriate controls, including access through the roof of the furnace to reduce the risk associated with the unstable linings On the next furnace a temperature of over 600C was recorded in the centre of the inspection hatch dictating immediate replacement during the shutdown.

During the work it was decided that it was necessary to 'box in ' the surrounding structure of the hatch to minimise future destruction.

Once the remedial work had been carried out, further thermography images were taken and compared with the earlier results to ensure the maintenance work had been effective.

As Chris Greenhalgh concludes; " Outsourcing gives Shell instant access to a very cost effective method of predictive maintenance, as and when they want it.

Using the extensive skills and resources of AVT removes the need for Shell to have their own expensive equipment and highly trained personnel which might only be used for a few days a year.

By building long term relationships with our clients, we can tailor our services to meet individual requirements.

Where appropriate, presentation of data and results can also be adapted to dovetail exactly with customers' own systems, allowing them to fit in with specific in-house procedures".