Patent ID: 6298796
Filing Date: 2001-10-09
Classification: F23C,F23D

Abstract:
A fine coal powder combustion method for a fine coal powder combustion burner, comprising the steps of:injecting a mixture of the fine coal powder and air with a fine coal powder nozzle, andinjecting air with at least one air nozzle arranged peripherally outside of said fine coal powder nozzle;supplying air in an amount in excess required for complete combustion of the fine coal powder from said air nozzles;forming a reducing flame at a high temperature (a flame, wherein a ratio of an actual amount of air to a necessary amount of air for burning completely the components released from the fine coal powder as gases is smaller than 1) by igniting the fine coal powder rapidly in the vicinity of the outlet of the burner and consuming oxygen rapidly;forming an oxidizing flame (a flame, wherein a ratio of an actual amount of air to a necessary amount of air for burning completely the components released from the fine coal powder as gases is larger than 1) having a uniform distribution of gas composition in a radial direction to a central axis of the burner by mixing the air injected from the air nozzle downstream of the reducing flame at the high temperature; andchanging the flow of the air injected from an air nozzle positioned at an outermost periphery of the burner with an angle in the range of 35-55 degrees to the fine coal powder injecting direction (axial direction);supplying a sufficient amount of air for complete combustion of the fine coal powder from the at least one air nozzle and making an injecting velocity of the fine coal powder flow injected from the fine coal powder nozzle be at least 20 m/s, wherein a ratio of momentum of fine coal powder flow at the outlet of the fine coal powder nozzle in the injecting direction (axial direction) to momentum of the air flow at the outlet of the air nozzle is set to be 1:5-7.