BURNING OF PULVEROUS OR GRANULAR RAW MATERIALS

摘要

1473034 Burning pulverous or granular materials F L SMIDTH & CO AS 11 May 1976 [16 May 1975] 20905/75 Heading F4B In a kiln plant comprising a kiln 1, a cooler 2 and preheater 3, raw material is fed to the plant partly through a pipe 14 leading to the preheater and partly through a pipe 8 for preheating in the cooler 2. Raw materials entering the cooler are carried by cooling air 26 in suspension counter currently to the kiln product 27 as indicated in Fig. 2. Air is drawn through the cooler by the fan 13 and raw materials pass with the air through the casing 11 (Fig. 1), and pipe 12 to unite with other raw material in the preheater 3 before passing into the kiln 1. The preheater 3 may include a calciner 4 supplied with fuel from the burner 6 and with heated cooling air from the pipe 12. Raw materials passing through the cooler may be sufficiently heated to be partially calcined before uniting in the calciner 4 with other preheated and partially calcined materials from the preheater 3. If the quantity of heated cooling air, after that taken by the preheater 3, is insufficient for the combustion of fuel in the kiln, an extra amount of atmospheric air may be supplied by a pipe 15, the air having been preheated by heat exchange in the heat exchanger 5 by exit gases from the kiln. The cooler may be of the grate type (Fig. 2) and raw materials from the pipe 29 may be blown in with air from the pipe 28 to pass in suspension above the hot kiln product. In further embodiments, the cooler may be of the rotary type and may include planetary cooling tubes (Fig. 9). Raw materials may be fed into the hot or cooler parts of the coolers or into the precooling zone of the kiln (Figs. 5-8). Raw materials may be fed to the cooler suspended in air or independently and may be made to mix directly with the kiln products and then agitated to separate them later. The apparatus may include a preliminary clinker cooling device (39), Fig. 3 (not shown), in the stationary casing.