What is the ratio of coal to limestone raw materials for lime shaft kiln
The ratio of coal to limestone raw materials in lime kiln is a key factor affecting production efficiency and product quality. The common ratio range is usually between 1:8 and 1:10, but this ratio is not fixed and needs to be dynamically adjusted based on various factors.
The calorific value of coal is the core factor determining the ratio. Taking smokeless coal with a calorific value of 6000 kcal as an example, calcining one ton of lime usually requires about 140 kilograms of standard coal. If converted by the mass ratio of coal to limestone, it is about 1:7.1. But when the calorific value of coal drops to 5000 kcal, the coal consumption needs to increase by 40%, and the ratio is adjusted to 1:5.1; When the calorific value is 4500 kcal, the coal consumption increases by 50%, and the ratio becomes 1:4.7. However, in actual production, a safety margin is often reserved to ensure sufficient calcination, so a ratio range of 1:8 to 1:10 is more practical.
The chemical composition of limestone also affects the proportioning. If the content of calcium oxide in limestone is low or contains impurities such as iron oxide, it is necessary to increase the proportion of coal appropriately to supplement the heat. For example, when the iron oxide content is high, the furnace temperature needs to be increased to promote the reduction reaction, and the coal to stone ratio may be adjusted to 1:9 to 1:10.
The production scale, equipment efficiency, and operational technology will also have an impact on the ratio. Due to higher thermal efficiency, the proportion of large-scale shaft kilns can be appropriately reduced; However, small shaft kilns or old equipment need to increase the proportion of coal to ensure production.
