Patent ID: 6186080
Filing Date: 2001-02-13
Classification: D21C,F23G

Abstract:
A recovery boiler comprising:a furnace having a furnace bottom and a furnace side wall;a burner for ejecting a black liquor into said furnace so as to form a char bed on said furnace bottom;a combustion air supply system comprising:a main air supply means for feeding air into said furnace so as to form a reduction atmospheric field with an air ratio of 0.8 or less surrounding the char bed formed on said furnace bottom,a first additional air supply means, disposed downstream of said main air supply means, for feeding air into said furnace so as to form a reduction atmospheric field where an air ratio of 1.0 or less and unburnt components exist, anda second additional air supply means, disposed downstream of said first additional air supply means, for feeding air so as to form a combustion zone where combustion completes; anda means for feeding one of a recirculated and an inert gas together with combustion air along said furnace side wall.