Amercentrale power station unit 9 (1996 project)
In 1996, the Amercentrale power station in the Netherlands found an unexpected problem in the chimney of its 600 MWe Unit 9. The internal brick liner of this large concrete chimney was under attack from highly acidic flue gas condensate. This condensate was permeating the ceramic brick and threatening to attack the concrete structure itself. The owner of the power station, EPZ, immediately started to look for a solution to this problem.
The Amercentrale power station is one of the country’s largest electricity producers and additionally, Unit 9 provides district heat (350 MW) to several nearby cities. Therefore, the availability of Unit 9 must be assured at all times. To find the right solution to the chimney problem, EPZ worked together with KEMA, the Dutch research institute for the power industry.
Many different approaches to the problem were analyzed, including the use of additional reheat to ‘dry out’ the flue gas, which comes from a wet flue gas desulphurisation plant. The clean gas is normally reheated to 60 °C and stays relatively humid. However, the policy of EPZ is to run its power stations at the highest possible efficiency and so additional reheat was ruled out.
As another option, the ceramic brick could be sealed by applying a suitable lining over its surface. Such a lining would have to be impermeable in order to really seal the brick from the condensate. Also, the lining should be able to cope with the many imperfections of a ceramic brick surface, such as open joints. Finally, EPZ demanded that the installation should take not one day longer than 3 weeks; additional, unscheduled downtime would be too expensive.
As to the desired durability of the lining: EPZ demanded a service life of 20 years. After comparing different options on the basis of their technical properties and field history, EPZ selected a PennguardTM borosilicate glass block lining for this project. In September of 1997, a PennguardTM lining was installed in the lower 75 metres of the chimney, on a surface of some 1.500 m2.