Silo combustion chamber and method for retrofitting same

A method for retrofitting a silo combustion chamber having a vertically extending flame tube with downward throughflow which can be fired from above, a casing surface of which is provided with a plurality of cooling fluid supply openings and is lined internally with a plurality of ceramic heat shield elements, wherein a plurality of lowest heat shield elements of the plurality of ceramic heat shield elements rest on a metallic supporting ring which has a circumferential support face extending horizontally, on which the plurality of lowest heat shield elements of the plurality of ceramic heat shield elements each rest with a contact face and the metallic supporting ring is provided with a plurality of radially extending cooling fluid bores, a conically tapered mixing tube arranged downstream of the vertically extending flame tube, into which a lower region of the vertically extending flame tube is set, and an outer housing which surrounds the vertically extending flame tube and the conically tapering mixing tube, forming an annular supply channel, comprising the steps:

• a) removing the plurality of lowest heat shield elements of the plurality of ceramic heat shield elements, and
• b) replacing the removed plurality of lowest heat shield elements with a plurality of substitute heat shield elements which each have a protrusion extending downwardly from the contact face and covering parts of the inside of the metallic supporting ring, wherein the plurality of substitute heat shield elements completely cover a radially inwardly oriented surface of the metallic supporting ring and reduce a partial volume flow of a working gas through the metallic supporting ring.