Supercritical boilers to improve efficiency at Medupi

14th December 2007 By: Jonathan Faurie

The supercritical boilers that are being supplied to the Medupi power station will improve the power station’s operating efficiency, says supplier Hitachi Power Africa’s MD Robin Duff.

In November, State-owned power utility Eskom signed two of the biggest commercial contracts in the company’s history. The boiler contract is worth a reported R20-billion and is a joint venture between Hitachi Power Europe and Hitachi Power Africa.

Medupi is set to be the biggest dry- cooled power station in the world. The supercritical design, with its higher efficiency, a first for Eskom, will result in better use of water and coal resources as well as reduced harmful emissions. The first unit is scheduled for completion towards the end of 2011, while the entire station is set to be completed by 2015. It is the first significant power station investment from Eskom in the past decade.

Duff reports that the logistics surrounding the execution of the project have been in planning since 2006 with Hitachi Power Europe.

Hitachi Power Europe is responsible for the offshore scope of the project. This includes the design and engineering of the plant, supply of critical components and high-grade materials and the required supervision in South Africa during the erection and commissioning phase of the project.

He adds that about 60% of the work will be done in South Africa by Hitachi Power Africa, which is responsible for the onshore scope of the project. The onshore scope of the project involves project management, quality control, manufacturing of structural steel, boiler pressure parts, commissioning and subcontracting of component supply.

Hitachi Power has selected Murray & Roberts as construction partner and DB Thermal for pressure part manufacture. Hitachi Power Europe will provide the necessary technical expertise and bring about the transfer of manu-facturing and erection know-how. At the signing of the contract, Hitachi Power Europe COO Klaus-Dieter Rennert said that facilities will be set up specifically to assist in the execution of this contract.

During the project peak, more than 2 000 people from Hitachi Power Europe and Hitachi Power Africa will be involved in the engineering, manufacturing, and construction of the boilers at Medupi. The project will consist of six boiler units, with working capacities of 800 MW.

In addition to the establishment of the facilities, Rennert said that Hitachi Power Europe will commit a considerable amount of time and effort to artisan training and the qualification of its local partners’ workforces to equip them to carry out the contract. “Hitachi Power Europe’s commitment in South Africa is long-term. The company looks upon the considerable investments that it is making in people and machines for Eskom’s capacity expansion programme as a contribution towards the development of South African society,” says Rennert.

Duff reports that design work on the plant has started with the manufacturing of the boilers scheduled to start next year. Site activities will start in the first half of 2009 and the units will go on line from late 2011.