Lepol grate

The preliminary experimental campaign was focused on the establishment of the kiln base line in terms of NO production with its original monochannel burner 80% of total heat input was supplied by the main burner and the rest through the auxiliary burner installed on the Lepol grate. 

At the beginning of the conversions that we will describe, the plant comprised two kilns, one of 1150 t/d, the other of 1350 t/d. Granulation was performed by mixing paste and raw meal. One of the kilns was equipped with a LEPOL grate and the other was a kiln with a cross shaped internal exchanger. The two coolers were FULLER coolers. 

The largest rotary kilns with grate preheaters (Lepol furnaces) have a capacity of up to 3()()() t clinker per day and those with cyclone preheaters up to 5000 t per day. In the latest developments the calcining is partly carried out in a preliminary step, in so-called precalciners, which are between the preheater and the rotary tube, to reduce the thermal loading of the rotary tube. The required clinker throughput can then be achieved with smaller rotary tubes or existing plants can increase their capacities. The largest plants with cyclone preheaters produce up to 8000 t/day. 

ACL Kiln or Lepol Kiln. ACL is a trademark of the Allis Chalmers Mfg Co., USA Lepol is a trade-mark of Polysius Co., Germany. Both terms refer to a travelling-grate preheater for portland cement batch prior to its being fed to a... 

The dust content of the exit gas from kilns with grate preheaters (Lepol kilns) is substantially dependent on the character and stability of the pellets and on the filtering action of the bed of pellets on the grate in the drying chamber. The dust collecting action of the intermediate gas cyclones can reduce the amount of dust arising in the drying chamber. 

The burner is located at the front of the LEPOL grid, and receives 20% of the total flow of coal. In order to withstand the new thermal loads, the bricks situated in the decarbonation zone have been replaced by others, richer in alumina the grate plates are now in 30 % chromium steel. The temperature of the grate is controlled and triggers an alarm in the case of too high a temperature. The height of the layer has risen from 18 to 24 cm and the rate of decarbonation from 24 to 47 %. 

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