Rybnik power station
Rybnik Power Station is the largest coal fired Power Station in the Upper Silesia area of southern Poland. Owned and operated by EDF Polska, Rybnik has a generating capacity of 1,775 MW (around 8% of Poland’s total energy use), spread across eight units.
In 2008, two new wet limestone flue gas desulfurization (FGD) plants were constructed to treat the gas flows from four units (each 215 MW). Rybnik Power Station also installed a 120 m high concrete chimney for the FGD plants, housing two steel flues, each 6.95 m in diameter.
To maximize the efficiency of the FGD plants, the owner chose to not reheat the desulphurized flue gas. Therefore the chimney operates as a “wet stack” carrying non-reheated flue gas with a temperature of 52°C. Non-reheated wet stack operation results in continuous condensate formation within the flues. To protect the steel flues against corrosion they were both lined with a sprayable organic coating. In addition, both flues were externally clad with 40 mm-thick glass wool insulation.
Wet stack operation is very demanding on chimney flue lining systems however, and after some time Rybnik Power Station found that small failure spots had developed in the lining resulting in localized corrosion of the steel flues.
In early 2012 the owner decided to investigate other options for lining the flues. The key selection criteria were: proven resistance to sulphuric acid condensate, reliability in a wet stack environment, and the possibility to perform installation within a limited outage.
The PennguardTM Block Lining System was selected for this task. In 2012-2013 Rybnik Power Station repaired the two flues by installing PennguardTM linings directly over the existing organic coating, mostly avoiding costly and time consuming repairs to the corroded steel flues.