Södra Cell is one of the world’s leading producers of market pulp. The company had initiated a program to extend the lifetime of the power plant at the Mörrum pulp mill by at least 15 years. Having looked at several different options, they concluded that investing in the existing facility would be the best solution for them. Among other actions, this meant upgrading the plant’s turbines and generators.
The turbo-sets at the plant are of the radial type, where one turbine is connected to two generators. These radial steam turbines are no longer manufactured and, due to the special design, it is also quite difficult to replace them with a new steam turbine and generator. However, from an economical and sustainability point of view, renewing the turbine and generator is advantageous, because they are reliable and very much appreciated in paper mill plants in particular because extracting steam for the process is easy.
Fortum eNext knows this type of equipment very well and was selected to rewind two rotors and stators.
“The fact that Fortum had previously dealt with this equipment was important. They are local and have the required engineering competence to perform this type of maintenance work here in Sweden. Based on our experience from previous collaboration, we felt that Fortum eNext was the natural partner,” says Ulf Wilhelmsson from Södra Cell.
The generators were dismantled in May, and the works are now ongoing at Fortum’s workshop in Västerås. But the project got under way earlier in the spring with the designing of the new stator windings and the purchasing of materials.
“The ability to do calculations on the generator’s electromagnetic side is the key here. When you work on an older machine, the calculations have to be replicated because the exact same materials are no longer available. So we have to update the design and calculate the complete generator according to today’s material and requirements,” says Senior Product Manager Gabor Csaba from Fortum eNext.
After the rewind, the generators will be able to be in service for many more years.
“Fortum eNext has invested in the generator workshop and facility in Sweden because we think it is important that we can offer this type of competence locally in the Nordics. Checking and refurbishing or replacing parts is important, but the main thing is the rewind. When the rewind is done properly, the stators and rotors will be more or less like new,” says Senior Bid Manager Jonas Holmgren from Fortum eNext.