| 摘要 |
PURPOSE: To attain a reduced ash content by sending a part of preheated coal to a combustion heating oven, introducing the coal into the lower part of a preheating tower together with combustion gas, preheating the coal by mixing the same with the dry coal present in the tower, and then removing coal particles not larger than a specific size. CONSTITUTION: Wet coal is sent from a hopper 1 to a drying tower 2, where the coal is dried to a water content of about 2-3% with a hot gas. The dry coal is separated from the carrier gas in a cyclone 3, and sent to a preheating tower 4. The gas separated is sent to a combustion heating oven 6 through a pipe 12 and heated. The preheated coal whose water content has been reduced to approximately 0% in the tower 4 is separated in a cyclone 5 from fine coal particles having a particle size of 250μm or smaller and from the carrier gas. The preheated coal is sent to a coke oven through a pipe 13. The carrier gas separated is circulated to the drying tower 2 through a pipe 9 and used for drying wet coal. 5-15wt.% of the preheated coal is taken out somewhere in the pipe 13, sent to the outlet of the oven 6, and sent to a lower part of the tower 4 together with a combustion gas. Thus, preheated coal reduced in ash content is obtained.
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