Kusile contract extended

Engineering business secures contract extension at power station

Our engineering business has secured a contract extension for Units 4 and 5 of the six new 800 MW boiler units at Kusile Power Station. Babcock was originally contracted by Mitsubishi Hitachi (the main boiler contractor for Kusile) for the balanced erection of five high-pressure pipework systems for unit 2 in 2014. Shortly thereafter, we were tasked with the same scope of work for Unit 3, and by September 2016 Units 4 and 5 were also included.

Scope of work

The scope of work includes the rigging and geometrical alignment of the piping for the main steam and hot/cold reheat systems in the boiler units. These boiler units deliver steam between the boiler and turbine, together with feed water and auxiliary systems and entail in excess of 1 000 welds per unit on piping ranging in diameter from 12 to 1 200 mm.

Lasers are used to position the pipework and precision to within 0.5 mm is demanded. As the boiler units are 115 m high, much of this work has to be carried out well above ground level, increasing the complexities of the project. Cranes are used for lifting the piping – weighing up to 782 metric tonnes per unit – into the boilers. The scope of work also includes coordinating the synchronised lifting of the pipe systems, with lifting and mechanical gear supplied by our plant services business.

By 2017 we expect to be working on all four units simultaneously in various stages of completion.

Our on-site crew currently comprises over 270 skilled workers ranging from welders to pipe fitters, engineers and quality control specialists.  The Kusile project requires specialised skills and workmanship with a focus on precise installation. We have a team of about 20 technical and logistical staff on site who are charged with ensuring that everything from rigging to alignment is accurately co-ordinated.

Skills development & risk management

A culture of safety has been instilled in the Kusile project team, with particular attention given to safety when working at great heights and near electrical equipment. The team has achieved 750 000 incident-free man-hours on site.

“We have steadily increased our scope of work on the Kusile project thanks to the proficient logistical, technical and project management skills we have brought to the table,” says David Brook, Technical Director – Africa.

The Eskom-owned Kusile Power Station consists of 6 supercritical boiler units that will produce 800 MW each, ultimately making Kusile one of the largest coal-fired power stations in the world. Unlike other power stations in South Africa, Kusile will make use of air-cooled condensers instead of the iconic cooling towers and the electricity generated is expected to ease the strain on the South African national grid. The supercritical boilers burn pulverised coal to produce steam at very high pressures (241 bar abs and 560°C), delivering this to the steam turbine that generates electricity. The process uses less fuel than in traditional sub-critical pressure boilers, making them more efficient with reduced emissions and operating costs.

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