Comprehensive comparison between mixed fired lime kiln and gas fired lime kiln
The core technological differences of lime kilns are reflected in the contact mode between fuel and materials, which directly determines the fundamental differences in calcination process, energy consumption control, and product quality.
The mixed combustion lime kiln adopts the method of mixing solid fuel (mainly coke or anthracite) with limestone raw materials and loading them into the kiln. The fuel burns inside the material layer, and the heat is directly transferred to the limestone through conduction and radiation. The advantage of this structure lies in its efficient utilization of thermal energy, relatively simple kiln structure, and less stringent requirements for fuel particle size. However, the ash generated after the combustion of solid fuels can mix into the finished lime, resulting in a decrease in product purity. At the same time, it is difficult to achieve precise zone temperature control, and local overburning or raw burning phenomena are prone to occur in the kiln, posing a challenge to the consistency of product quality.
Gas fired lime kilns use gas fuels (such as natural gas, generator gas, coke oven gas) to heat limestone externally by spraying flames into the kiln through burners distributed around the kiln body. This combustion method thoroughly separates the fuel from the material, ensuring the high purity of the finished lime. By independently adjusting the gas and combustion air volume of each burner, the temperature distribution inside the kiln can be precisely controlled, achieving balanced calcination and obtaining products with better activity and highly stable quality. The core of its technology lies in the complex combustion control system and the design of airflow distribution inside the kiln.
From the perspective of energy consumption and environmental protection, gas fired kilns usually have higher thermal efficiency than traditional mixed fired kilns due to their sufficient combustion and sensitive heat regulation. In terms of environmental protection, the treatment of exhaust gas in gas fired kilns is more direct, as it only needs to deal with the flue gas generated by limestone decomposition, while mixed fired kilns also need to deal with more complex pollutants generated by solid fuel combustion, which increases the difficulty and cost of treatment accordingly. The selection of kiln type requires comprehensive consideration of key factors such as fuel resources, product grade requirements, and environmental regulations.
