Abstract: A boiler and a method in a boiler producing thermal energy, the method including: combustion or fuel and combustion air in the furnace of the boiler, delimited by walls; receiving of thermal energy by a steam superheater placed on the wall of the furnace and including at least one heat exchange surface, and supplying of gas or a gas mixture to the front of said heat exchange surface to form a barrier layer for protecting the heat exchange surface from flue gases developed in connection with the combustion. At least one supply device is provided in the superheater or in the direct vicinity of the superheater, to supply gas or a gas mixture to the front of said heat exchange surface to form a barrier layer to protect the heat exchange surface from the flue gases in the boiler.

Abstract: A boiler (1) comprising at least: a furnace (2), in whose lower part the combustion used as the primary source of thermal energy of the boiler is configured to take place; devices (6) for supplying fuel into the furnace; devices (3, 7, 8, 26) for supplying combustion air into the furnace; one or more flue gas ducts (11); at least one chamber (17) accommodating at least one steam superheater (15) for recovering thermal energy. Said chamber is configured to allow a direct line of sight (16) between said superheater and said primary source, to enable the reception of thermal energy by means of thermal radiation. Said chamber is further configured to prevent the entry of said flue gases (19) to said superheater either totally or almost totally, to avoid the reception of thermal energy by convection.

Abstract: A supply and a method for preventing corrosion on heat exchange surfaces of a boiler. Additional material is fed to flue gases of a boiler by at least one supply for additional material. The supply includes a cooled case beam that is hollow inside and several nozzles for feeding the additional material.