Process and apparatus for preheating coking coal

摘要

Coking coal is preheated and dried by passing hot carrier gas into a generally vertical flash drying pipe, then passing comminuted coal into the same pipe, the carrier gas being blown with a flow speed to move the coal upwards in the pipe and passing at about the midpoint of the pipe a mixture of hot combustion gases and additional hot recycle gas branched off from the other hot waste gas line into the pipe so as to cause further heating and moving of the coal, the further heating being carried out in a uniform and gentle manner. At the end of the pipe the coal and carrier gas are separated and the coal is recovered while the waste gas are recycled into a blower and therefrom into the vertical flash drying pipe with a branch leading part of the recycle gas into a mixing chamber with the combustion gases so as to lower the temperature of the combustion gases when the same are passed into the pipe.