Detailed Introduction to the Process Principle of Lime Vertical Kiln
Lime vertical kiln is a traditional lime production equipment, and its process principle is based on the calcination and decomposition reaction of limestone. The process principle of lime vertical kiln, including its structure, working principle and main process flow.
The overall shape of the lime vertical kiln is vertical cylindrical, mainly composed of key components such as kiln shell, refractory brick lining, insulation layer, combustion system, ventilation system, limestone loading system, unloading system, and control system. The kiln shell is the main structure of the vertical kiln, which is welded from steel plates and has good strength and sealing properties. The refractory brick lining laid internally is used to withstand high temperatures and resist the erosion of limestone. The insulation layer is located on the outer side of the refractory brick lining to reduce heat loss and improve thermal efficiency.
In principle, the lime vertical kiln works according to the principle of counter current heat transfer. The materials inside the kiln move from top to bottom, and the flue gas passes through the entire column from bottom to top. The materials are preheated, calcined, and cooled inside the kiln. This process has strict requirements for the block size of the raw materials entering the kiln, generally 25150mm, and requires graded loading to ensure that the ratio of the maximum block size to the minimum block size does not exceed 23.
The main process flow includes raw material preparation, material loading into the kiln, calcination of lime, cooling of quicklime, and grinding of lime powder. During the raw material preparation stage, limestone or other limestone minerals are crushed, ground, and processed to produce limestone powder with a certain particle size. During the unloading and kiln loading stage, the prepared limestone powder is transported into the vertical kiln through a conveying device to form a certain layer of material. During the calcination stage of lime, the fuel in the lower part of the vertical kiln is ignited, and the high temperature generated by combustion is used to calcine the limestone, decomposing it into quicklime. This process is completed in the roasting zone of the kiln chamber, which is divided from top to bottom into the preheating zone, roasting zone, and cooling zone. The preheating zone allows limestone to absorb the heat from the rising hot air inside the kiln, gradually increasing the temperature and causing water to evaporate; The roasting zone causes limestone to undergo decomposition reaction under high temperature; The cooling zone exchanges heat with cold air to cool the calcined lime. After the quicklime is cooled, the smoke and dust in the furnace are discharged through the exhaust pipe, and then further cooled by devices such as coolers to reach the appropriate temperature. Finally, the cooled quicklime is ground by a grinding machine to produce lime powder.
The lime vertical kiln achieves efficient calcination and decomposition of limestone through its unique structure and process principle. Although this traditional method has gradually been replaced by new lime production equipment, in some areas, lime vertical kilns are still widely used due to their stability and economy.
