Investigation of the thermal stresses in lump coals when heating them in a rotary furnace

The problem of the formation of the granulometric state of coke, which has been thoroughly researched in connection with a grate-process of coking fragmented caking coals and charges, has been investigated less in connection with the coking of weakly-caking and noncaking lump coals. In the authors' opinion, when coking a freely superimposed lump-coal layer, the formation of the granulometric state of the coke takes place somewhat differently. Freely superimposed layers of lump coals can be regarded as elementary layers whose thickness is the same as that of fragments undergoing coking which are not connected to each other. During the thermal treatment of such a composite layer, the fracturing in each elementary layer (lump) will obey the same laws as during layer-coking in reverbatory furnaces. However, in virtue of the fact that the elementary layers (or lumps of coal) are not interconnected, they will not affect each other (unlike coke-oven clinkers). Consequently, each elementary layer (or lump) will be subjected to heating through depending on its position in the charge, and to fracturing; the result will be the sum-total of these elementary processes. From the technological point of view, it is important to determine the heating mode in which lumps ofmore » coal are not fractured. The calculation performed made it possible to qualitatively assess how the thermal fracturing of initial coals takes place.« less