Doosan Škoda has overhauled a 135-MW steam turbine at a heating plant in the Czech Republic.
After six years of operation at the Kladno heating plant, the two-casing steam turbine was opened for the first time to be upgraded for years of future, safe and reliable service, Doosan Škoda reported. The 588-MW Kladno facility serves close to 35,000 customers.
Since more than 30 bars steam at temperatures exceeding 535°C flow into the turbine at full power, the turbine had to be shut down and cooled before the inspection so that it could be stripped of the insulation, steam pipes dismantled, screws in the split plane loosened and the unit “opened”. Only then could all of the internal parts – particularly the casings, guided wheels and the rotors which have more than 25 steel blade stages – be inspected, sandblasted where needed and tested.
“Most of the repairs were done right at Kladno heating plant,” Jaroslava Soysal, project manager with Doosan Škoda Power, said in a statement. “Only the rotor from the combined high- and medium-pressure section and the guided wheels from the low-pressure section were hauled to the Pilsen Plant to replace the sealing elements.”
The most technically challenging step was repairing the turbine’s parting plane, the company pointed out. The Doosan Škoda Power engineers used 3D scanning and computer modelling for this job. With this technology, a model of the outer casing parting plane was created that enabled the technicians to assess the deformations, which were subsequently welded, ground down and scraped away.
Partially owing to this progressive 3D scanning method, the upgrade was completed one day ahead of schedule.
Sev.en Energy Group in August formally acquired the Kladno and Zlin plants from Alpiq AG. The Kladno plant features units fired with coal, gas and biomass and has about 250 employees.