Magnetic conditioner keeps gearboxes cleaner

Innogy is applying revolutionary Magnom magnetic field conditioning technology at Didcot A power station.

Innogy is a utilities company responsible for the operation and maintenance of a diverse range of power stations.

Its engineers have a continual responsibility to review operating practice with a view to improving efficiency, extending asset life and, importantly, to achieve and where possible exceed increasingly stringent environmental targets.

Didcot A, the 2040MW coal-fired power station first commissioned in 1972, is a prime example of how such policies can be effectively implemented in practice.

To meet some of these demands, a joint project between ExxonMobil and Innogy was initiated to improve the reliability of coal mill gearboxes, which in turn led to the search for a much less restrictive lube oil circuit to maintain oil pressure at elevated temperatures.

Having reviewed numerous options available, Innogy turned to the revolutionary Magnom magnetic field effect conditioning system to address the problem.

Magnom, supplied by Fluid Conditioning Solutions (FCS), is a revolutionary product comprising a series of annular magnets and innovatively designed formed steel plates.

Through its patented design, the Magnom removes ferrous (and other) contaminant of less than 1um, from a wide variety of fluids, including the smallest and most abrasive of particles that are responsible for the destructive chain reaction of wear, thus lending the technology to the enhanced transmission protection that has been demonstrated at the station.

The Magnom's unique design ensures a negligible pressure drop across the unit.

As the fluid flows through the highly focused magnetic field, contaminants are drawn out of the fluid flow and into special collection zones.

These zones hold significantly more contaminant than a conventional filter without obstructing fluid flow or risking "wash-off" commonly associated with other magnetic separation devices.

Having identified this potential solution, it was decided to install a single process unit as a replacement to the existing edge filtration system on the external oil circuit of one of the station's coal mill gearboxes.

This application was considered to be particularly stringent due to the high viscosity of the synthetic lube oil in use (ISO VG320 and 460).

It very quickly became evident that the primary objective (maintaining oil pressure at elevated temperatures) had been realised with no discernible pressure drop across the unit.

And this has subsequently been maintained.

More significantly, the resulting improvements in oil cleanliness have been a real bonus with a dramatic reduction in ferrous contaminant and additional reductions in aluminium, silicon, copper and soot levels.

This is evidenced in oil analysis data from the ExxonMobil Oil Analysis Service.

Here it can be seen that the ferrous levels, previously running at a dangerously high level of 350-450ppm dropped to a consistent 40-50ppm.

The data also show a positive influence of the unit on the other nonmagnetic contaminants of concern.

Following the dramatic success of the Magnom trial, Innogy is now undertaking a planned schedule of work to integrate the technology on all 32 coal mill gearboxes.

The benefits of extended oil life and reduced consumption, coupled with exceptional dirt holding capacity, mean that routine maintenance can be reduced to a minimum, with the units requiring cleaning every three to four years only, well within the schedule for routine outages.

In today's environmentally sensitive culture, an ever increasing drive to continually improve quality while seeking to reduce costs and increase competitiveness has ensured a bright future for new technologies that can provide practical solutions to these issues.

The experience at Didcot A has shown the Magnom to be such a technology.

Many forward thinking global organisations are now incorporating the technology into their future strategies with FCS fully committed to supporting this drive and to further develop and apply the technology through strategic partnerships.

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