How to determine the reasonable height and diameter of the lime vertical kiln during the design phase
In the design of lime vertical kilns, the reasonable matching of kiln body height and diameter directly affects calcination efficiency, product quality, and energy consumption level. The following are key design principles and methods:
1. Determine the diameter based on production capacity demand
The diameter of the kiln body (D) mainly depends on the production capacity requirements, usually calculated based on the unit cross-sectional area production capacity (1.5-2.5 t/m ² · d). For example, if the designed production capacity is 200 t/d and 2 t/m ² · d is selected, the cross-sectional area needs to be 100 m ² and the diameter ≈ 11.3 m (rounded to 11-12 m).
2. Determine the height based on the calcination time
The height (H) of the kiln body should ensure that the limestone has sufficient residence time (usually 8-12 hours) inside the kiln. According to the material descent rate (0.5-1.2 m/h), if the calcination time is 10 hours, the effective height is approximately 6-12 m. Considering the reasonable distribution of preheating, calcination, and cooling stages, the total height is usually 3-5 times the diameter (e.g. D=3 m, H=9-15 m).
3. Optimization of aspect ratio (H/D)
Excessive aspect ratio (such as H/D>5) can easily lead to increased airflow resistance and energy consumption.
Too small aspect ratio (such as H/D<3): Insufficient calcination time and increased firing rate.
It is generally recommended to have H/D=3.5~4.5, taking into account both thermal efficiency and calcination uniformity.
4. Other influencing factors
Fuel type: Gas kilns can be lowered appropriately, while coal-fired kilns need to increase their height to ensure full combustion.
Raw material particle size: For large limestone particles, the calcination time should be extended and the height should be appropriately increased.
Reasonable design should be combined with process testing and simulation calculations to ensure that the kiln structure is economically efficient.
