Lime kiln

The environmental protection vertical lime kiln has formed several product series with daily outputof 80t/d to 400t/d. Its advantages of environmental protection, low carbon, energy saving and wasteutilization, and intelligent control have completely solved the long-term poor quality of finished products, high product energy consumption, etc. Typical problems such as serious environmental pollution, low degree of automation and high labor intensity, our company's small lime kiln has the advantages of high CO2 concentration, high effective calcium content in the product, and low investment. Itis widely used in light calcium carbonate and chlor-alkali industries; large-scale The development and construction of lime kilns have been highly praised by customers in the steel, chemical, calcium carbide and alumina industries across the country.

A lime shaft kiln is a cylindrical kiln body. Materials are added from the top of the kiln and discharged from the bottom after calcination. According to the temperature changes and distribution inside the shaft kiln, the shaft kiln is divided into three zones from top to bottom: the preheating zone, the calcination zone, and the cooling zone. In the preheating zone, the materials are preheated by the heat of the flue gas. In the calcination zone, the materials are calcined with the heat released by the combustion of fuel. In the cooling zone, the calcined material exchanges heat with the cold air blown in. The material itself is cooled, while the heated air enters the calcination zone as combustion-supporting air. To ensure that each section of the material calcination process proceeds fully and completely, the three belts inside the shaft kiln should be maintained at a certain height and strive for stability. There are two reasons for the movement of materials in the shaft kiln: one is that the volume contraction of the materials during the calcination process causes the movement of the upper layer of materials; Another type is the movement of all the materials in the kiln caused by the discharge of the materials at the bottom.

During the descent of the material, it undergoes a complex heat exchange with the hot gas, accompanied by the decomposition of limestone and the development and growth of quicklime grains. When the entire process is completed, it is also cooled by the combustion air to a temperature 60℃ higher than the ambient temperature. Then, the lime is discharged to the belt conveyor outside the furnace by the disc exit aircraft and the two-stage sealing valve without leaking the combustion-supporting air. After being lifted by the elevator and screened, the lime with a particle size of ≤5mm and >5mm is respectively discharged into different silos.

The combustion-supporting air is blown into the furnace from the bottom by the Roots blower, overcomes the resistance of the material particles and rises to the top of the furnace from the bottom. Under the suction of the dust removal induced draft fan, the flue gas is conveyed through the pipeline to the dust collector for dust removal. Due to the effect of the induced draft fan, a slight negative pressure zone (about -10Pa) is formed above the material surface in the kiln. This slight negative pressure ensures smooth airflow inside the furnace, which is very conducive to the decomposition of limestone in the calcination zone. The induced draft fan introduces all the flue gas into the dust collector for purification, and then discharges it into the atmosphere through the chimney in compliance with standards.