Process for treating noncaking coal to form passivated char

摘要

A continuous process for treating a noncaking coal to form stable char. The process includes the sequential steps of drying the coal to remove moisture therefrom and form a dry coal; pyrolyzing the dry coal by progressively heating substantially all of the coal to a temperature sufficient to vaporize and remove low end volatile materials from the coal to form char and sufficient to mobilize at least a portion of high end volatile materials within the char and at least partially collapse micropores within the char. The char is then cooled to a temperature sufficient to demobilize the volatile materials within the at least partially collapsed micropores of the char to pyrolytically passivate the char. The 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 oxidatively passivate the coal by chemisorption of oxygen. The oxidatively passivated char is then substantially simultaneously rehydrated and cooled to form a char having about 5-10 wt % moisture and then conveyed to a final passivation vessel wherein a process gas having about 3%-21% by volume oxygen flows through the vessel to finally passivate the rehydrated char by chemisorption of oxygen.