Abstract: A method for decreasing nitrogen oxides of a pulverized coal boiler using burners of internal combustion type including during the operation of the boiler, ignition sources in the burners of internal combustion type mounted on side walls of the boiler are always in a working state, and igniting the pulverized coal in the burners in advance; decreasing secondary air amount in a primary combustion zone of the boiler so that the primary combustion zone is in a relatively strong reducing atmosphere and an oxygen-deficient condition for inhibiting generation of NOx is created; and supplying remaining air from an upper part of a furnace of the boiler in a form of over-fire air, so that a deep air staging is carried out in the total furnace. Thus, the NOx generation of combustion can be effectively controlled on the premise of not decreasing efficiency of the boiler.

Abstract: A pulverized coal burner and a pulverized coal boiler. The coal burner comprises a primary air cylinder (111) and a pulverized coal concentration device (112). The coal concentration device (112) makes the concentration of the coal flow gradually decrease from inside to outside along the radial direction, with respect to an axis (100) of the primary air cylinder (111). The coal burner further comprises a coal separating cylinder (113) and a coal guiding cylinder (114) located downstream of the device (112), the rear end of the cylinder (113) is connected with the front end of the coal guiding cylinder (114). The outlet of the cylinder (114) has a conical expansion portion (1141). The coal burner further comprises a divergent nozzle (115) connected with the rear end of the primary air cylinder (111) and whose cross-sectional area gradually increases along the flow direction of the coal flow.

Abstract: A pulverized coal concentrator for a pulverized coal burner, the concentrator is fixedly arranged inside the pulverized coal burner and comprises a front part (102) and a rear part (101), wherein the front part (1020 is designed as a bowl-shaped structure, for guiding and concentrating an air-pulverized coal flow, and the rear part (101) is designed as a cylinder-shaped structure, for maintaining a proper extension of the dense phase zone of the air pulverized coal flow. Also a pulverization coal burner is provided comprising the pulverized coal concentrator, in particular an internal combustion-type pulverized coal burner. The pulverized coal concentrator increases the adaptability of burner to coal quality, air velocity and pulverized coal density.

Abstract: A pulverized coal burner and a pulverized coal boiler. The coal burner comprises a primary air cylinder (111) and a pulverized coal concentration device (112). The coal concentration device (112) makes the concentration of the coal flow gradually decrease from inside to outside along the radial direction, with respect to an axis (100) of the primary air cylinder (111). The coal burner further comprises a coal separating cylinder (113) and a coal guiding cylinder (114) located downstream of the device (112), the rear end of the cylinder (113) is connected with the front end of the coal guiding cylinder (114). The outlet of the cylinder (114) has a conical expansion portion (1141). The coal burner further comprises a divergent nozzle (115) connected with the rear end of the primary air cylinder (111) and whose cross-sectional area gradually increases along the flow direction of the coal flow.

Abstract: A pulverized coal concentrator for a pulverized coal burner, the concentrator is fixedly arranged inside the pulverized coal burner and comprises a front part (102) and a rear part (101), wherein the front part (1020 is designed as a bowl-shaped structure, for guiding and concentrating an air-pulverized coal flow, and the rear part (101) is designed as a cylinder-shaped structure, for maintaining a proper extension of the dense phase zone of the air pulverized coal flow. Also a pulverization coal burner is provided comprising the pulverized coal concentrator, in particular an internal combustion-type pulverized coal burner. The pulverized coal concentrator increases the adaptability of burner to coal quality, air velocity and pulverized coal density.

Abstract: A method for decreasing nitrogen oxides of a pulverized coal boiler using burners (2) of internal combustion type comprising: designing or changing all or part of burners of the pulverized coal boiler as internal combustion type burners (2), in which the ignition sources may be plasma generators (1) or ignition devices such as small oil guns etc., and the power thereof can be adjusted for controlling the ignition intensity in the burners (2). The burners (2) are interiorly divided into several stage combustion chambers (5) and are provided with pulverized coal concentrators (4) which do deep fuel staging in the burners (2).