When Corrocoat SA was approached by Eskom Medupi Power Station – one of the world’s largest coal fired power plants – to provide corrosion protection for six stainless steel flue cans, they realised that this would be a major challenge. The cans were located at the top of Eskom’s chimney stacks, so all the work would have to be carried out 220m above ground.
Their solution in this oxygen depleted environment where temperatures could reach 120°C.,was based on the use of Corrothane XT, which offers outstanding chemical resistance coupled with continuous protection at high operating temperatures. For the cooler external surfaces POLYGLASS VE was recommended
Corrocoat was subsequently appointed as the nominated contractor for the project which was to be completed in two phases. Eskom instituted a General Outage for three weeks when the stacks were completely shut down, offering these periods to complete the removal of the borosilicate bricks, apply Corrothane XT to the internals of the flue cans, and the re-installation of new bricks over the top of the applied Corrothane XT.
The Project In Numbers
• 6 x 9m diameter flue cans to be protected with a total surface area of 2,640m2.
• 800 litres of Corrothane XT and XTHA plus 3000 litres of Polyglass VE and VEHA used to complete the work.
• 130 tonnes of abrasive blast media used – all of which had to be carried up to the top of the stacks, along with 3 x blast cleaning machines, air receivers and attendant air and blast hose, nozzles, PPE etc.
• All equipment and materials were winched to the top of the stacks and conveyed using either a ratchet-type ‘Torga’ elevator which took a minimum of 20 minutes to reach the top – or one hour each way by foot!
• 700 linear metres of sharp edges to grind and radius on the stainless steel substrate.
• 1300 linear metres of stripe coating hand applied.
Working 200m above the ground required careful forward lanning including providing a constant supply of drinking water for the crew, ablution facilities, and the availability when needed of all materials, small tools and other equipment at the work face.
Overall the project presented a number of challenges to the Corrrocoat SA team, not least the extreme height and simply getting to the cans at the start of each shift. The need to transport materials for blasting and coating to the
top was an enterprise in itself and put real physical stress on personnel who had to work with restricted access, in specialist safety equipment and to the tightest health and safety requirements.
During the shutdown periods, Corrocoat SA successfully completed the application of the Corrothane XT lining internally to all six cans, as well as over the top of the flue cans and down the initial two metres externally.
A successfully completed major project at one of the world’s largest coal fired power plants, requiring a team of 35 to apply 4000 litres of specialist coatings, to strict time constraints and at a height of 220m…. that’s a contract that shows the expertise and resourcefulness of the Corrocoat SA team and one they can be justifiably proud of.