Main problems and energy-saving potential analysis of lime shaft kiln
Lime shaft kiln, as a traditional lime calcination equipment, is widely used in small and medium-sized production, but its technical bottlenecks and energy consumption issues restrict sustainable development. The current main problems focus on three aspects:
Unstable calcination quality: Due to uneven particle size of limestone, imbalanced fuel ratio, and defects in the air supply system, there is a tendency for raw or over burning to occur in the kiln. For example, when the particle size exceeds the 40-80mm standard, heat conduction is hindered, leading to sandwich burning; Fuel calorific value below 5500 kcal or uneven air distribution will exacerbate insufficient calcination.
Equipment aging and structural defects: issues such as peeling of refractory bricks in the kiln body and air leakage at the kiln roof result in heat loss, with a thermal efficiency of only 50% -60%. Due to design flaws, some kiln types suffer from air flow segregation and material accumulation, exacerbating energy consumption and waste.
Dual pressure of environmental protection and energy consumption: Traditional shaft kilns lack waste heat recovery devices, and the waste heat from flue gas is directly discharged. Insufficient combustion can easily produce excessive nitrogen oxides.
In response to the above issues, the energy-saving potential of lime kiln can be achieved through technological upgrades:
Optimization of kiln structure: Four layers of refractory materials are used to build the kiln skin, reducing heat loss, and combined with an automated material distribution system to improve particle size uniformity, which can increase thermal efficiency by 5% -7%.
Waste heat recovery and utilization: Installing heat pipe heat exchangers to recover waste heat from flue gas, which can be used to preheat the air entering the kiln or dry raw materials, can reduce comprehensive energy consumption by 3% -6%.
Combustion system upgrade: Optimizing the fuel to air ratio through AI algorithms, reducing excess air coefficient, and improving combustion efficiency by 10% -15%.
If combined with measures such as raw material pretreatment and automated monitoring, the overall energy-saving potential of lime shaft kiln can reach 8% -10%, with both economic and environmental benefits.
