What is the heating rate of lime kiln ignition
The ignition and temperature rise of lime kiln is a key link in production start-up, and its speed control directly affects the life of the kiln body and subsequent production stability. According to the differences in kiln types, the heating rate needs to be precisely controlled in stages:
1. Standard for heating up conventional shaft kilns
(1) From room temperature to 200 ℃: control the heating rate at 30-50 ℃/h
(2) Stage of 200-600 ℃: Maintain a uniform heating rate of 50-80 ℃/h
(3) 600-900 ℃ range: Reduce speed to 30-50 ℃/h
(4) 900 ℃ to working temperature: 20-30 ℃/h slow heating
The total heating time is usually controlled within 18-24 hours
2. Special requirements for rotary kilns
(1) Initial rotation stage of cylinder (＜ 200 ℃): heating rate ≤ 30 ℃/h
(2) Refractory expansion period (200-600 ℃): 40-60 ℃/h
(3) Final heating before feeding (600-1100 ℃): 25-35 ℃/h
Need to cooperate with a slow rotation system of 0.2-0.5r/min
3. Key control parameters
(1) Monitoring of kiln expansion: expansion per meter length ≤ 3mm/h
(2) Temperature difference of refractory materials: internal and external temperature difference ＜ 80 ℃
(3) Exhaust gas temperature gradient: fluctuation in the heating stage ＜ ± 20 ℃
4. Handling of abnormal situations
(1) Local overheating (temperature difference>100 ℃): Immediately stop heating and keep warm for 2 hours
(2) Cracking of refractory materials: Cooling down to below 300 ℃ for inspection and repair
(3) Uneven expansion: Adjust the burner angle and reduce the heating rate by 50%
In practical operation, it is recommended to use an intelligent temperature control system and achieve automatic adjustment through multi-point thermocouple monitoring. The combustion system should be checked once every quarter to ensure the stability of the ignition heating process. Standardized heating operation can extend the service life of refractory materials by more than 30%.
