Method and apparatus for renewing a vertically disposed steam generator,

Abstract

A vertically disposed steam generator includes a pressure vessel containing: a tube plate, chambers, a bundle of U-shaped bent heating tubes with supporting anchors, a steam trap above the heating tubes, and tubes for a secondary medium discharging into the pressure vessel. The heating tubes have ends guided through openings in the tube plate and discharging a primary medium into the chambers. A method and apparatus for renewing the steam generator includes disconnecting the tubes for the secondary medium; dividing the pressure vessel into an upper region forming a steam dome and a middle region with a jacket surrounding the bundle of heating tubes while leaving a lower region having the chambers; successively raising the steam dome, the steam trap and the jacket; disconnecting the heating tubes and the anchors above the tube plate, and raising the entire bundle; removing remaining parts of the heating tubes from the tube plate and preparing free openings for receptacles of new heating tubes; introducing a prefabricated new bundle having new anchors and heating tubes, introducing the ends of the new anchors and heating tubes into the openings of the tube plate and connecting the ends of the new anchors and heating tubes to the tube plate; and replacing the disconnected jacket, the raised steam trap and the disconnected steam dome, and reestablishing the previous connections of the tubes for the secondary medium.