Influence of coal-charge density and carbonization rate on coke

A method for continuous carbonization of coal in a traveling bed is now being developed. One of the principal features of this new carbonization technology is significant mechanical consolidation (by approximately 40%) of the coal charge as it moves along the oven. The charge density is a regulable technological factor in this case. Moreover, the use of corundum refractories with high thermal conductivity as the oven lining can provide high carbonization rates. Study of coke quality and oven output rate in the carbonization of consolidated charges at high rates is therefore of practical interest. Experimental carbonization tests were conducted in a 200-kg corundum oven 410 mm wide, 1000 mm long, and 1000 mm tall. They made it possible to determine coke quality and oven output rate as quantitative functions of charge density, charge caking properties, and temperature regime. Mechanical consolidation of the coal charge (all other conditions being equal) promoted an increase in the yield of metallurgical coke, improvement of its M25 and M10 indices, and an increase in furnace output rate, despite a decrease in the carbonization rate; the amount of coke belonging to the >60 mm class was governed principally by the temperature in the heating walls formore » both consolidated and unconsolidated charges; an increase in heating-wall temperature (within limits) made it possible to increase the furnace output rate by 20 rel. % and to reduce the abradability index M10 by 0.7%; and consolidation of the coal charge compensated for the detrimental effect of the leaner blend produced when the proportion of gas coals was raised.« less