EXHIBITIONS
must be embedded below the bottom of the sea to ensure sufficient stability. As pile-driving is extremely
noisy (with a level above 160 dB or more), suitable precautions must be taken to protect marine life. Nowadays, however, there are a number of alternatives to pile-driving, such as injection and vibration piling. This reduces the noise level and also the mechanical impact on the foundation pipe. To bear the enormous weight
of an entire structure, the pipes must have thick walls and large diameters (several metres). At a 5-MW facility, for instance, the gondola with its rotor and hub alone weighs between 300 and 400 tonnes, sometimes more. In addition, there are several hundreds of tonnes for the wind turbine and the transition piece between the foundation and the turbine.
XL and mega monopiles To cope with such large volumes and to use monopiles at ever- increasing depths of water, specialist pipe manufacturers are continually entering new territory in terms of dimensions. At the beginning of the millennium it was possible to produce pipes of about five metres in diameter for plant engineering purposes. Today, however, the standard diameter of a pile is over six metres, and the pile can be used at a depth of about 30 metres. The Dutch Sif Group believes
it should be possible to increase the length of a monopile to 120
metres, its diameter to 11 metres, and its weight to 2,000 tonnes. Anticipating such developments, the company has been expanding its production capacities, so that it can eventually produce such pipes in series. In the near future, however, Sif believes that it is sufficient to make foundations with 9-metre diameters which are 100 metres long and weigh 1,500 tonnes.
Other manufacturers, too, are
now opting for the production of such XL, XXL or mega monopiles. EEW Special Pipe Constructions GmbH in Rostock produces large, longitudinally welded pipes, with thick walls, up to 10 metres in diameter, up to 120 metres in length and up to 1,500 tonnes in weight. This is currently the most cost-effective foundation structure for offshore wind farms with turbines in the 5-to-8-MW class, at a depth of up to 40 metres. According to the manufacturer, this allows savings of up to 30 per cent on foundations compared with a jacket design. Such savings are apparently substantial, as foundations account for 20 to 25 per cent of the total cost in an offshore project. Mega monopiles are also
being studied by a workgroup at Dillinger Hüttenwerke which has worked with the company’s subsidiary Steelwind Nordenham on setting up a special manufacturing facility for such foundations. The first monopile that was produced in Nordenham in September 2014 had a diameter of 7.8 metres and weighed
around 1,000 tonnes. It was also the biggest of its kind. Yet it is possible to build monopiles up to 10 metres in diameter, up to 120 metres in length, up to 150 millimetres in wall thickness and up to 1,500 tonnes in weight. Such piles can apparently be used at a water depth of up to 45 metres.
Tough, high-strength steel is required Dillinger Hütte is also one of the main suppliers of heavy plates for the production of monopiles. To make these, the company has developed steels with thicknesses far above 100 millimetres and in a strength category of up to 500 MPa (megapascal). Preference is given to firmer, mechanically rolled steels, in particular. Foundation structures require steels that are extremely tough, robust and weldable. This is because welding is one
of the main stages required in the production of a monopile. To put it in simple terms, the sheet metal is formed into lengths of pipe segments, using 3- or 4-roller bending machines. The inside and outside longitudinal seams of the individual lengths are then welded on a welding line, and the finished individual lengths are taken to a production line where they are welded together into a single large segment. Alternatively, it is possible to pre-mount smaller segments consisting of two or three lengths and then to combine them on the same large-segment production line.
Highly automated production routines Having reached this so-called growing line, the final component is then assembled. The individual lengths or small segments are aligned with one another, using special turning and alignment tools, and the components are stapled together. The inner and outer circumferential seams are then welded together, using a column and boom and applying a submerged arc welding technique. In this way the components are gradually assembled to form the actual monopile which is taken to the next manufacturing stage, i.e. finishing and coating. Continuous, highly automated production warrants a good level of capacity utilisation and cost-effective manufacturing of offshore wind turbine foundations. Wind farms are unlikely to
be on display at the next Tube trade fair. However, there will be plants and machinery for the cost-effective manufacturing of monopiles and other foundation structures. Moreover, where wind energy technology is concerned, it makes perfect sense to combine this leading international pipe and tube fare with the world’s biggest wire and cable trade fair, wire.
Press contacts for Tube 2018: Petra Hartmann-Bresgen, M.A. Ulrike Osahon Tel. +49 (0) 211 4560-541/-992 Fax +49(0)211 4560-87 541 Email: HartmannP@messe-
duesseldorf.de
16 IMT June 2016
www.internationalmetaltube.com
Photo:istock©bruce0116
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36