Shaft Kilns Discharge

The lime, cooled somewhat by the entering air in the lower parts of the shaft kiln, is discharged intermittently and slaked to calcium hydroxide with... 

Figure 6.11 Discharge system for a shaft kiln. (Reproduced by permission of J.A.H. Oates.)...

Table is a cone-shaped insert, usually of metal, placed just above the discharge of a shaft kiln to give more uniform movement of the burden down the shaft. 

Shaft Kiln. A vertical kiln charged at the top and discharged at the bottom. If solid fuel is used it is fed in with the charge, but shaft kilns can also be fired with gas or oil by burners placed nearer to the bottom of the shaft. Such kilns are used for the calcination of flint, dolomite, fireclay, etc. 

In the Walther-Beratherm shaft cooler the upper part of the shaft is of reduced diameter in order to increase the cooling air flow velocity in this part and thus produce a fluidized bed effect with the object of distributing the incoming clinker (discharged from the kiln) over the whole shaft cross-section and improving the heat transfer. 

The measuring and control instrumentation for a shaft cooler is somewhat less elaborate than that for a grate cooler. The control duties to be performed are similar, however. The column of clinker in the cooler must be maintained at constant height irrespective of the rate at which clinker is discharged from the kiln. 

With planetary, rotary and shaft coolers the fluctuating rate of clinker discharge from the kiln due to ring formation and coating movements causes high and markedly varying final clinker temperatures, since the radiation heat losses remain substantially constant and the cooling air rate available to these coolers can practically not be altered. 

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