| 摘要 |
PROBLEM TO BE SOLVED: To form a uniform flow speed distribution by a method wherein an outer diameter of a rich or lean separator at an axial center part of a fine powder coal pipe is a frustoconical shape with its flowing-in side being smaller than a flowing-out side, an outer diameter at the flowing-out part as well as a flowing-in side diameter and a flowing-out side diameter of a cut slit passing through an axial center line are made to have a rate of a specified range with the inner diameter of the fine powder coal pipe. SOLUTION: Fine powder coal mixture gas 02 is fed to a rich or lean separator 13 together with primary air. In this case, a slant angleθof the frustoconical shape of the separator 13 is 60 deg. to 90 deg., an inner diameter of the fine powder coal pipe 05 is defined as D, a diameter d1 of a front flow side of a hollow recess slit is set to (1/10.5) D to (1/20.5) D, a diameter d2 at the rear stream side is set to (1/5.5) D to (1/10.5) D and an outer diameter d3 of the rich or lean separator 13 is set to (1/1.55) D to (1/3.5) D, thereby mixture gas at an outer side having a high fine powder coal concentration and a low fine powder coal concentration at a central part is formed in the fine powder pipe 05. With such an arrangement as above, it is possible to eliminate staying of gas caused by eddy flow which may easily be generated at a wall surface of the rear-side flow of the rich-lean separator 13 and to make a uniform flow speed distribution.
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