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Abstract

A continuous process for treating coal to form stable coal char by passivating the coal and then rehydrating and cooling the product thereof to prevent spontaneous ignition. The process includes the steps of pyrolyzing the coal to vaporize and remove low end volatile materials and to mobilize high end volatile materials and cooling to demobilize the high end volatile materials within the at least partially collapsed micropores of the coal char to pyrolytically passivate the coal char and form a char having about 14-22 wt % high end volatiles. The pyrolytically passivated coal char is then conveyed to a reaction vessel wherein a process gas having about 3%-21% by volume oxygen flows through the reaction vessel to at least partially fluidize the coal char and oxidatively passivate the coal by chemisorption of oxygen. The passivated coal char is then substantially simultaneously rehydrated and cooled to form a stable coal char having about 5-10 wt % moisture.

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First Claim