Carbonisation or gasification of oxidised coal dust - using product gas to preheat the coal for oxidn.

摘要

In the rapid carbonisation and/or gasification (partial or total gasification) of pulverised coking coal, in which the coal is subjected to rapid preoxidation to reduce its caking power, the preoxidation is effected during pneumatic transport of the coal, and the coal is heated to the preoxidation temp. (e.g. 400 degrees C) by direct heat exchange. The process is characterised by the fact that all or part of the gas produced in the process after sepn. of coke dust, is contacted in one or more stages with the coal to be heated, and that at most the 0.005 mm fraction of the coal particles (ranging in size from 0 to 0.2, pref. 0 to 0.1 mm) is heated briefly (for 0.1 sec.) to a temp. in the plastic range of the coal (e.g. 480-500 degrees C). The process utilises the sensible heat of the gas to preheat the coal without significant caking (the 0.005 mm fraction has the lowest content of caking components).