The kiln is usually turned by means of a single Girth Gear surrounding a cooler part of the kiln tube, but sometimes it is turned by driven rollers. The gear is connected through a gear train to a variable-speed electric motor. This must have high starting torque in order to start the kiln with a large eccentric load. A 6 x 60 m kiln requires around 800 kW to turn at 3 rpm. The speed of material flow through the kiln is proportional to rotation speed, and so a variable speed drive is needed in order to control this. When driving through rollers, hydraulic drives may be used. These have the advantage of developing extremely high torque. In many processes, it is dangerous to allow a hot kiln to stand still if the drive power fails. Temperature differences between the top and bottom of the kiln may cause the kiln to warp, and refractory is damaged. It is therefore normal to provide an auxiliary drive for use during power cuts. This may be a small electric motor with an independent power supply, or a diesel engine. This turns the kiln very slowly, but enough to prevent damage.
Lime rotary kiln flame shape can be adjusted, within the wind flow and wind outflow reasonable matching precalciner kiln feed CaCO3 decomposition rate of up to about 90%, domestic precalciner kilns are mostly three-duct or the four winds. Road burner. Outflow wind velocity should be appropriate, this can perhaps control the firing zone a little longer, in order to facilitate the high silicic acid burn-in and fine particles are homogeneous clinker cause. For delay the flame low temperate mobilization or coal quality is poor, burning slow, you can perhaps increase the flow wind, adding to the outflow of the wind; if the coal is good or kiln skin is too thin, high temperature kiln. should increase the outflow of the wind, adding within the wind flow. Caused by the outflow of air damper excessive flame too long, floating kiln skin produce too long, kiln temperature will be ultra-high; within the...