Craiova Power Station
The 400 MW coal fired Craiova Power Station in Romania needed to refurbish its existing chimney. The chimney was a 200 m / 656 ft high, conical reinforced concrete shell, which was internally protected by a sectional ceramic brick liner. The brick liner was placed on concrete supports, attached directly to the concrete shell. Between the shell and the brick liner was a narrow space, filled with a thermal insulation material.
A 1999 technical survey of the chimney showed that flue gas could penetrate into the space between the concrete shell and the brick liner. As a result the concrete shell and the brick lining supports were under attack from sulphuric acid condensate. Furthermore, thermal cycling had created wide cracks in the concrete windshield. Any further deterioration of the chimney would be an unacceptable risk, especially if the earthquake risk in the area was also considered.
Based on a design by a leading chimney construction company, GIP Grup, the chimney was completely refurbished in 2002. Instead of using ceramic brick again, the existing brick liner was removed and the internal concrete surface was relined with the Pennguard® Block Lining System.
The chimney repair method and Pennguard® lining installation procedure are described and shown on page 2 and 3 of the Project Report.
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The new Pennguard® lining on the inside of the chimney will protect the concrete shell from acid condensate attack. The Pennguard® lining also helps to increase the earthquake resistance of the chimney. By removing the 1,500 metric tons brick lining and installing a 95 metric tons Pennguard® lining, the forces transmitted to the concrete shell during an earthquake will be strongly reduced.
Many customers considering the use of Pennguard® lined concrete chimneys have asked:
- How will the Pennguard® lining itself behave, when the concrete shell is subject to great strain and crack formation during an earthquake?
- Will the Pennguard® lining also crack and will it be dislodged from the concrete shell?
The University of Melbourne investigated these questions at the specialized test laboratories of its Department of Civil and Environmental Engineering.
The findings are published on page 4 of the Project Report.