GB547115A - Improvements in vacuum treatment of coking coals - Google Patents

Abstract

547,115. Coking processes ; materials for making coke and other products. AMERICAN CYANAMID CO. July 2, 1941, No. 8361. Convention date, July 2, 1940. [Classes 55 (i) and 55 (ii)] The coking characteristics of caking coal are altered by drying the powdered coal and subjecting it to vacuum (e.g. 28 inches of mercury) for about 15 minutes, releasing the vacuum, and allowing contact of the coal with air for about 30 minutes, followed by a second vacuum treatment for about 15 minutes while maintaining the coal at about 150‹ C. during the whole treatment. Powdered coal treated in this way may be used in the manufacture of briquettes, sulphite liquor, coal tar, or pitch forming a binder, and undue swelling of the briquettes when carbonized being avoided. Coal is ground to pass a 20 mesh screen in a pulverizer 1 the temperature of which is controlled by hot flue gases from a furnace 4. Air from a fan 3 carries the coal particles through a pipe 6 to a cyclone separator 7 from which the hot air returns to the fan 3, and the hot and dry deposited coal is delivered by a pump 10 and pipe 11 to vessels 14. A smaller fan 8 removes air from the main current, and blows it through a collector 9 from which the coal returns to the pulverizer. The coal is aerated by hot air from pipe 12. The vessels 14, when filled, are subjected to a vacuum of 28 inches of mercury insulation in the vessels maintaining the temperature at 150‹ C. The vacuum is broken after 15 minutes, and air is admitted, the pressure remaining at atmospheric for 30 minutes, after which, a further vacuum treatment takes place. Air under high pressure may be admitted instead of air at atmospheric pressure. The treated coal is discharged into a bin 16.