Marine boiler structure

Abstract

Provided is a marine boiler structure that is capable of remedying non-uniformity in corrosion progression by making the temperature distribution of combustion gas that passes through a superheater uniform, and that is also capable of reducing the level of NOx contained in the combustion gas. In a marine boiler structure configured such that combustion gas generated by combustion in a burner flows from a furnace through a superheater and an evaporator tube bundle, a bottom air port that supplies part of the combustion air as bottom air from a furnace bottom portion of the furnace is provided, the bottom air port is positioned closer to the superheater relative to a burner center line, and an ejecting direction of the bottom air is set within a range inclining in the burner direction from the vertically upward direction.

1 . A marine boiler structure configured such that combustion gas generated by combustion in a burner flows from a furnace through a superheater and an evaporator tube bundle, comprising:
 a bottom air port that supplies part of the combustion air as bottom air from a bottom portion of the furnace,   wherein the bottom air port is positioned closer to the superheater relative to a burner center line, and an ejecting direction of the bottom air is set within a range inclined in the burner direction from the vertically upward direction.   
     
     
         2 . A marine boiler structure configured such that combustion gas generated by combustion in a burner flows from a furnace through a superheater and an evaporator tube bundle, comprising:
 a side air port that supplies part of the combustion air as side air from an upper portion of the furnace,   wherein the side air port is positioned closer to the superheater relative to a burner center line, and an ejecting direction of the side air is set, with reference to the vertically downward direction, within the range inclined toward both the superheater and the burner.   
     
     
         3 . A marine boiler structure according to  claim 2 , wherein the side air port is arranged in the same blast box as the burner.