Mechanical Technology Archive

In his August comment, Peter Middleton cites Eskom’s winter availability improvements as an argument in favour of prioritising maintenance and investing in modern monitoring technologies and asset management strategies.

Peter Middleton Comment Mechanical TechnologyAs promised in May, Eskom has managed to get us through the winter without having to resort to load shedding. Energy availability has risen to close to its 80% mark, with unplanned and planned maintenance numbers not much higher than the 10% thresholds targeted by the utility before winter began.

Successes highlighted by group chief executive, Brian Molefe, in his July System Status Briefing include:

  • A projected reduction of OCGT energy use from 1 801 GWh in Quarter 1 of 2016 to 16 GWh for Quarter 2, which amounts to a 98% decrease in energy from diesel generators and direct diesel costs reduced from R3.9-billion down to R86-million.
  • An energy availability record of 81% for the month of June, 2016, last achieved in July 2013.
  • An overall availability increase from 66.3% in December 2015 to over 80% in July 2016.

Most significantly, Eskom claims that the improved performance of its plant is not due to lower demand – as many of us cynics have suggested. Available capacity is significantly higher, while demand is not significantly different from 2015. Available capacity for this year is greater than the peak demand for 2015 (34 481 kW) and 2016 (34 899 kW).

The energy crisis in South Africa has, undoubtedly, focused attention on the necessity and the value of maintenance, along with the dangers of unplanned breakdowns. In addition to the obvious production and substitution cost consequences, though, Eskom’s brand perception has been close to destroyed. Even with performance on an upward trend for many months, the utility is still finding it hard to regain peoples’ confidence, let alone their pride.

In the ‘Mario on maintenance’ column this month, Mario Kuisis talks about the practical side of condition-based maintenance and outlines the four main pillars of condition monitoring: vibration analysis; oil analysis; infrared thermography; and ultrasound detection. The aim of all the technologies is to permit in-service condition assessment whilst the plant is in normal production,” Kuisis writes, through “trending the results of periodic condition assessments”.

In a medium sized plant, Kuisis suggests, there is limited scope for continuous on-line monitoring simply due to economics. “Even though it is the ideal solution, it is typically confined to critical assets only.” Included in his piece is a comprehensive table outlining which assets can benefit from the different condition monitoring technologies.

Says SKF’s Sarel Froneman in our lead Proactive maintenance, lubrication and contamination management article this month: “With rotating machinery as the core focus, we develop maintenance solutions based on asset criticality, to most cost effectively maximise uptime and minimise failure risks and ownership costs.” He cites a success at a coal mine in Limpopo – being developed to support Eskom coal-fired units in the area – where SKF IMx multi-log online condition monitoring units are being installed to protect the mine’s critical assets. It is heartening to see investments in modern asset management systems and condition monitoring equipment being prioritised in new mining installations in South Africa.

Technology, in general, is increasingly reliable. If one compares a modern motorcar of any brand to its 25 year-old predecessor, reliability experiences and expectations are a generation apart. Vehicles have, for as long as I can remember, been fitted with overheating and oil-pressure warning systems. Today, though, cars are full of sensing, engine and condition management systems that can continually calculate fuel consumption, inform when a service is due, alert to an unclosed door or unfastened seatbelt and protect the vehicle against further damage should any hint of a sub-system failure be detected. Today’s cars are possibly more expensive, but don’t they have a longer life? Aren’t the efficiencies much higher and the running costs lower?

As with any article on proactive maintenance, Kuisis addresses the question of how the investment money can be justified in “today’s depressed business climate”. He also cites the longer life, lower costs of ownership and the efficiency benefits associated with condition monitoring investments.

There are other spinoff advantages. Prioritising equipment and plant health can create confidence, drive improved performance and efficiency and cultivate a positive and responsible mindset across an organisation.

Ultimately, South African producers have to provide better quality at lower costs in order to compete on the global stage. Investments in modern maintenance strategies and systems could be a healthy starting point in achieving these imperatives.

Eskom’s experience should remind us of the dangers of neglecting maintenance when times are tough. Its recent turnaround is directly due to maintenance being prioritised from the very top.

So as Mario Kuisis asks in his conclusion, “What are we waiting for?”

Contact Mechanical Technology

As from January 2017, Chemical Technology and Mechanical Technology have merged to form MechChem Africa.


Title: Editor
Name: Peter Middleton 
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Fax: +27 11 615 6108

Title: Editor
Name: Glynnis Koch
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Fax: +27 11 615 6108

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Name: Brenda Karathanasis
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