Vertical Shaft Lime Kiln

Limestone and coke from mine are transported to plant, after sieve, the two kinds of material mix together with some ratio, the mixture will be evaluated to the top of lime kiln, it’s distributed by a distributor inside the kiln to avoid separation during discharge. When the lime goes down in the kiln, it will be preheated by the gas from the bottom. The gas will be cooled by the raw lime, the temperature of exhausted gas can be less than 120℃, so the heat can be recovered very well. The thickness of refractory is 1m, the temperature of the kiln shell can be less than 40℃, which is the minimum heat radiation, there are 4 thermocouples in different kiln level to monitor the situation in the kiln calcination, if there is any problem the temperature will indicate the problem. lime will get fully calcination when it falls inside the kiln because our kiln has enough height to fulfill the process. The lime after calcination will get cooled by the air from the bottom, the temperature of discharged lime can be less than 50℃. So the heat brought by product also is recovered. This is the reason why our heat consumption can be as low as 850Kcal/kg. The gas will be treated by bag filter, so the emission will match the requirement of law. The system is operated in minus pressure, so there isn’t pollution goes out in all the plant. All the motor in process control will be controlled by frequency converter, it’s very easy to operate in DCS control system.

All the system only need 3persons in one shift: 1 person for truck loader driver, 1 person for DCS control operator and 1 person for maintain patrol.