摘要 |
<p>A method and apparatus for drying low-rank coals, such as lignite, where the coal is passed through a sealed vessel in a plurality of heated fluidized beds, with fluidization effected by superheated steam flowing countercurrent to the coal flow. A composite steam is exhausted from the sealed vessel and passed to a vessel where water is sprayed therein to cool the same and remove occluded solids. A first portion of the steam is then reheated and returned to the sealed vessel as fluidizing steam, while a second portion of the steam is heated and passed through heat exchange tubes in the sealed vessel to heat the fluidizing coal, with the second portion, after passage through the heat exchange tubes discharged from the system.</p> |