What is the kiln temperature control strategy for rotary kiln lime kiln
The temperature control strategy of rotary kiln lime kiln needs to take into account calcination efficiency, lime quality, and energy consumption safety. Its core system is as follows:
Setting of graded temperature control targets
Divide the preheating section (600-800 ℃), calcination section (950-1150 ℃), and cooling section (<600 ℃) along the axis of the kiln body. Using multi zone independent temperature measuring elements (K-type thermocouples or infrared sensors), a temperature position curve model is established through a PLC system, and the set values of each zone are dynamically adjusted. The temperature fluctuation in the calcination section should be strictly controlled to be ≤± 15 ℃ to avoid burning or overburning.
Fuel air coordinated regulation
Configure a variable frequency coal feeder and a proportional gas valve, and adjust the air-fuel ratio in real-time based on the O ₂ content (3% -5%) at the kiln tail. Adopting a dual duct burner to achieve staged combustion, the primary air ensures fuel atomization, and the secondary air controls flame length. Set up negative pressure monitoring at the kiln head (-20Pa to -50Pa), maintain a slight negative pressure state through a variable frequency fan, and prevent flame overflow.
Optimization of kiln body motion parameters
The speed (0.8-1.5 r/min) and inclination angle (3% -5%) are linked for control. If the speed is too fast, the material layer will be too thin (<200mm), and if it is too slow, it will cause local overheating. Install a layer thickness radar detector, establish a speed layer thickness PID control loop, and ensure that the material layer in the calcination area is stable at 300-400mm.
Intelligent compensation mechanism
Introduce an online detection device for the calorific value of limestone, which automatically adjusts the fuel dosage when the content of raw material CaCO3 fluctuates. Configure an AI vision system to monitor the color (whiteness value) of quicklime at the kiln tail and provide feedback to adjust the temperature in the calcination section. Set up an emergency water cooling system that automatically triggers spray cooling when the kiln temperature exceeds 1200 ℃.
Collaborative management of waste heat and emissions
Install a waste heat boiler in the cooling section to recover the heat from the exhaust gas (300-400 ℃) for preheating the combustion air. The kiln tail dust removal system (bag+electrostatic precipitator) needs to be matched with kiln pressure fluctuations to maintain a dust removal efficiency of>99.5%. Establish a CO concentration warning (alarm when>800ppm) and adjust the burner air supply in conjunction.
This strategy, through parameter coupling control and intelligent compensation, can increase the kiln temperature qualification rate by 20%, reduce heat consumption by 12% -15%, and meet environmental emission requirements.
