Fourth Largest Coal-Fired Power Station in the World
Upon completion, the Kusile power station, located in the Mpumalanga district of South Africa, will become the fourth largest coal-fired power plant in the world.
This station, with a total capacity of 4,800MW, is part of the Eskom group (South African public electric utility) and will be the first power station in South Africa to install flue-gas desulphurisation (FGC) to remove sulphur oxides (SOx) from exhaust flue gases.
The search for the most environmentally-friendly solutions not only included the production of electricity itself (once the electricity will be running through the high voltage lines), but was also a concern long before the opening of the power station.
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The stored coal and coal ash, which will be produced, are a major threat to the environment; however, each will be confined in a sealed area measuring approximately 1 million square meters (10.8 million square feet) divided into three sections.
State-of-the-art engineering, design and technology are ensured by WBHO Construction, one of the largest construction companies and contractors in South Africa. Currently, two layers of geomembranes and five composite liners are being installed by several teams. The coal storage area will be specifically covered with two layers of 1.5 mm thick HDPE geomembrane, while the coal ash will require two layers of 2 mm thick HDPE membrane.
The installation of the geomembranes, including the most sensitive part (which is the welding of the overlapping geomembranes), is executed under the auspices of WBHO engineers and installation specialists. For the Kusile power station project, WBHO utilizes the entire range of geo welding equipment manufactured by Swiss-based, Leister Technologies.
The initial welding work, dating back to 2013, was completed using several ASTRO wedge welders, extrusion welders, hand tools and test equipment of the Leister brand.
The ASTRO already reached high productivity at a speed of 2.0 to 2.2 meters (6.5 to 7 feet) per minute. At the end of 2014 and early 2015, WBHO stepped-up its production to a new level as an early adopter of the all new GEOSTAR wedge welder from Leister.
Since using the new welders, productivity at the site has nearly doubled—with welding speeds reaching 3.5 meters (11.5 feet) per minute—on textured geomembrane. Long welds, measuring 120 to 230 meters (394 – 755 feet) are mastered in a single pass thanks to the GEOSTAR and its new features that enable the permanent monitoring of weld pressure, speed, temperature and voltage as well. The reduced weight of this new machine, compared to its predecessors, and its height-adjustable chassis, enable even easier handling in any given terrain.
To ensure a flawless project, state-of-the-art maintenance of the installation equipment is provided by Plasti-Weld, Leister’s exclusive distribution and service partner in South Africa.
Leister Sales and Service Center: Plasti-Weld
Customer: Eskom group (South African public electric utility)
Material: HDPE geomembrane
Leister Products: ASTRO and GEOSTAR
Text / Photos: Leister AG and Plasti-Weld