Analysis of calcination parameters and the temperature profile in an annular shaft kiln. Part 1: Theoretical survey

In article certain specific problems associated with heat transfer, which occurs during the process of lime burning are discussed. An increase in the thickness of the calcinated layer affect the conditions of heat inflow into the sphere. The equilibrium calcination radius is defined, which delimits the calcination process into two zones: one in which the supply of heat to the reaction front limits the heat transfer from kiln gases to the stones, and another, which is limited by heat conduction through the already calcinated layer. The phenomenon of the critical sphere radius is also discussed. From the viewpoint of increasing the capacity of existing annular shaft kilns, it turns out that it is a advantageous to increase the heat transfer coefficient from kiln gases to the stones up to the value of 60 W/(m2 K) in the incipient part of the calcination.