CEMENT MATERIAL PREHEATER AND ITS REMODELING METHOD

PROBLEM TO BE SOLVED: To minimize the circulation of raw powder in the system, to reduce the power by decreasing a pressure drop, to increase heat efficiency, to stabilize operation, to increase production and to improve the stability in product quality by using a highly efficient dust collecting cyclone on the maximum-temp. side and/or on the minimum-temp. side among the multiple cyclones constituting the cement material preheater. SOLUTION: The suspension preheater 10 as a cement material preheater consists of multiple cyclones 11, 12, 13 and 14. The waste gas from a rotary kiln 16 is introduced into the first cyclone at about 1100 deg.C and discharged outside the system from the fourth cyclone at about 350 deg.C. The cement material is introduced from a raw material feed part 15, and the material collected by the fourth cyclone is mixed into the waste gas from the second cyclone and separated by the third cyclone. The separated material is mixed in the waste gas from the first cyclone and introduced into the second cyclone. The process is repeated, the speed of the waste cyclone gas is controlled to >=25m/s at the outlet of the inner cylinder, and the insertion length of the inner cylinder is adjusted to >=0.7 times the height of the inlet duct.