Method of decreasing ash fouling

摘要

A furnace burns coal where the coal is decreased to a fine size to expand the surface of the carbon in the coal to a predetermined amount of free oxygen from air to militate against reduction of alkali compounds in the coal. Further, the temperature of the combustion is controlled to a predetermined maximum by recirculation of cooled flue gas to complete the control over the alkali compounds in the coal and prevent the formation of tube-fouling silicates.