Study On Cold Movement Of Raw Meal In KDS Calciner

As the core equipment of precalciner kiln,the operation effect of calciner directly affects the quality of cement and the firing heat consumption.When the raw meal dispersion in thecalciner is poor,the CO and NO_x in the system are high,and there are problems such as high heat consumption,serious ammonia escape,crust and core material.The KDS calciner was selected as the research object,and the solid model of the calciner was made by using theKDS calciner of a cement company as the prototype(1:40).The sectional wind speed of the calciner is set at 5m/s,study the flow field in the calciner with PIV principle,shoot the raw meal movement video(960 frames)in the calciner,and study the raw meal movement in the calciner.Here are the main conclusions:(1)The axial wind speed of the bottom half of the calciner and the cone shows a trend of“high center and low side wall”,and exist a reflux zone at the edge of the cone of thecalciner.The maximum axial velocity of the tertiary air was 7.38m/s when the valve is half opened,which is located near the center of the calciner.The minimum value was-1.23m/s,which is located in the reflux area of the edge of the cone.(2)The tangential velocity of raw meal at the edge of the calciner was 1.59m/s and 1.47m/s,respectively,when the tertiary air valve is fully opened and half opened.When the raw meal is fully opened,the speed of raw meal is slightly larger,but the difference is only 8%.The adhesion force at the edge should be the main influencing factor of raw meal movement at the edge of the calciner.(3)When the Angle of the spreader board is 30°and the feeding amount is changed(the ratio of solid to gas is 1.24-1.92kg/Nm3),the Angle between the feed flow and the horizontalplane is basically unchanged,and the height of the impact on the opposite calciner wall is similar.the Angle of the spreader board is the main factor affecting the material dispersion.(4)The smaller the Angle of the spreading plate,the smaller the Angle between the material flow and the horizontal plane,and the lower the height of the impact on the opposite calciner wall,the better the material dispersion effect.(5)The raw meal in the central part leaves rapidly with the air flow,and the raw mealattached to the edge moves in a spiral shape.While rotating around the calciner edge,the raw meal slowly rises,and a part of the raw meal stalls and falls in the process of rotation.(6)When raw meal enters the calciner,it does not enter along the center line of the calciner,but shift under the influence of tertiary air.