摘要 |
PURPOSE:To improve the combustion efficiency of coal and eliminate the problems of dust explosion or the like by a method wherein air is permeated through an oxygen permeable membrane to divide the air into oxygen enriched air and nitrogen enriched air and the powdered coal is burnt by utilizing the oxygen enriched air while the coal is pulverized under the existence of the nitrogen enriched air. CONSTITUTION:When the air, introduced into an oxygen enriching device 2 is passed through the oxygen permeable membrane 3, the air is turned into the oxygen enriched air by passing oxygen selectively, the oxygen enriched air is taken out of a conduit 4 to send it to a burner 7 by a blower 5 through the conduit 6 and burns the powdered coal, supplied through a supplying line 8 to heat and calcine the material of cement in a rotary kiln 9 at temperature of 1,450-1,500 deg.C thereby producing clinker. On the other hand, the nitrogen enriched air, obtained from the device 2, is sent into a heat exchanger 10b bia the conduit 12 and is heated to predetermined temperature, thereafter, is introduced into a dryer 18, while the dried coal and the powdered coal, retrieved by a cyclone 19, are transported to a pulverizer 13, thereafter, are pulverized under the existence of the nitrogen enriched air. |