Patent ID: 9052106
Filing Date: 2015-06-09
Classification: F23C,F23L,F23N,Y02E

Abstract:
1. A method for optimising combustion conditions in a fluidised-bed boiler where oxygenous combustion gas is fed at two or more height levels, the first of which is a primary level (P), which is located at the height of a furnace bottom, and the second is a secondary level (S), which is located close to fuel feed height (F), above which secondary level (S) there can be still other combustion gas feed levels (T, . . . ), characterised by producing combustion gases ( 15 a , 15 b ; 16 a , 16 b ; 28 a , 28 b ) having different oxygen contents by mixing together air and pure oxygen or circulated flue gas at such a ratio that each combustion gas is provided with a desired oxygen content, and by feeding at least one of said combustion gas feed levels (P, S, T, . . . ) at different points in the horizontal direction of the furnace with combustion gases ( 15 a , 15 b ; 16 a , 16 b ; 28 a , 28 b ) having different oxygen contents such that zones of different oxygen contents are formed in the horizontal direction of the furnace.