What are the reasons for the increase in raw firing rate in lime vertical kilns
Lime vertical kiln is an important equipment for producing quicklime, and its calcination effect directly affects the quality of quicklime. However, in the actual production process, lime vertical kilns often encounter the problem of increased firing rate, which not only affects the quality of quicklime but also reduces production efficiency. The following is an analysis of the reasons for the increase in the firing rate of lime vertical kilns.
The particle size and quality of raw materials are important factors affecting the firing rate. The particle size of limestone is generally between 40mm and 90mm. If the particle size is too large or too small, it will affect the calcination effect of quicklime. When the raw material particles are too small, the resistance of the material layer increases, and the power consumption of the fan is constant, it is difficult to maintain the stability of the material layer, resulting in incomplete calcination and increased firing rate. In addition, if the raw materials contain a large amount of impurities, they may not react quickly during the calcination process, resulting in incomplete reactions and increased burning.
Improper thermal operation is also one of the reasons for the increase in firing rate. Thermal operation is a key step in calcining high-quality quicklime, and the main thermal parameters include temperature, air volume, and air pressure. The temperature inside the kiln is mainly divided into preheating zone, calcination zone, and cooling zone, among which the temperature in the calcination zone is the most important, generally ranging from 800 ℃ to 1100 ℃. In thermal operation, if ash discharge and feeding are carried out simultaneously, and limestone is moved to the cooling zone until ash discharge when the temperature in the calcination zone is insufficient or the reaction is not complete, it will affect the quality of quicklime and increase the firing rate.
Unreasonable air supply is also an important reason for the increase in burning rate. The stone materials in the lime vertical kiln are heated and calcined by fuel combustion, and uneven air supply can lead to overburning. On the section inside the kiln, some areas have high air volume while others have low air volume. In areas with strong winds, there is sufficient air to support combustion, and the raw materials and fuels react fully, resulting in better quality calcination; However, in areas with low air flow or high resistance, if the air flow cannot flow smoothly, it will lead to incomplete decomposition of limestone during the calcination process, resulting in burning.
Equipment failure may also lead to an increase in the burning rate. When the production equipment is running, sudden power outages or inadequate maintenance by personnel can cause the equipment to suddenly stop running, resulting in blockages in the feeding and ash discharge systems in front of the kiln and affecting the calcination effect of quicklime. At the same time, thermocouples used to measure the internal temperature of vertical kilns are prone to inaccurate measurements under long-term high temperature conditions, which can affect the calcination effect.
The main reasons for the increase in the firing rate of lime vertical kilns include the particle size and quality of raw materials, improper thermal operation, unreasonable air supply, and equipment failure. In order to reduce the burning rate, improve the quality and production efficiency of quicklime, it is necessary to start from these aspects and take corresponding measures to improve and optimize.
