A method of subjecting badly swelling and/or caking coal to an oxidizing pretreatment prior to coking to improve the coking properties thereof

摘要

641,422. Oxidizing fuel. AMERICAN CYANAMID CO. Jan. 8, 1947, No. 643. Convention date, Jan. 16, 1946. [Classes 50 and 55(i)] I , To enable briquetted swelling coals to be coked under a temperature rise of at least 2‹C per minute through the plastic range, the coal pulverized so that at least 95 per cent of the particles pass through an 8- mesh screen and dried, is subjected at about 150‹-275‹C and 2-20 lbs. per sq. in. pressure to oxidation by a gas containing less oxygen than air and preferably about 5-15 per cent for a period of a few seconds to a few minutes to destroy a part only of the coking quality of the coal. A strongly coking coal is passed through a drying pulverizer 2 and hopper 3 into a fluidizing pump 4 and thence through a retort 6 in an oxidizing atmosphere, a cooling coil 8 into a hopper 11 for feeding a briquetting unit 19. The retort is heated-by. circulating highboiling fluid through a jacket or e.g., electrically.. The fluidizing air which supplies the oxygen enters the system through a valve 28, the oxygen content being controlled by admission n-of flue gases from the heater 20 for the high-boiling fluid The mixture flows through a filter 31, a moisture absorber 32, a com pressor 34 and valve 36 to the pump 4. In an example a very strongly coking coal known as Thrislington washed nuts is pulver ized to 88 per cent minus 28 mesh and passed through the oxidizing zone comprising 5 per cent oxyger at 180‹C under 10-15 lb pressure per sq. in. in 2-3 minutes. Sulphite liquor and tar-acid binders are referred to. Specification 547376 is referred to.