Role and Influence of Primary Air and Secondary Air in Rotary Kiln
Date：2020-11-16 Source：zk corp Views:
One. Definition of Main Wind
The main wind refers to the wind used in the rotary kiln production system to inject fuel into the kiln and form a flame through cyclone and axial wind. The main wind is also the normal temperature wind sprayed from the burner nozzle. The main wind includes quiet wind and coal wind. Calm wind refers to the general term including direct current, cyclone and central wind. Coal wind refers to the wind used to transport pulverized coal.
Two. Impact of Strong and Small winds
1. The main effects of strong wind on the rotary kiln are as follows:
1.1 Reduce the thermal efficiency of the kiln. In the case of constant exhaust volume, low temperature is too high, which will inevitably reduce the high temperature secondary air volume of the kiln, thereby reducing heat recovery.
1.2 The high oxygen atmosphere is conducive to the formation of combustion Nox. The use of burners to increase thrust and reduce primary air is the main measure to improve thermal efficiency.
2. Main effects of small wind on the rotary kiln are as follows:
2.1 It is difficult to form a stable flame if the wind is too small, and the secondary air cannot be wrapped in the primary air, which is not conducive to flame stability and pulverized coal ignition, and the burning speed is slow.
2.2 It is not conducive to volatile combustion, because the oxygen in the primary air is volatile combustion, and the amount is small, which affects volatile combustion, but reduces the flame burning speed.
2.3 Small winds can easily cause the pulverized coal to sink. The transportation of pulverized coal requires a suitable wind speed, otherwise some coarse particles in the pulverized coal will fall into the air duct, which will affect the stability of the burner and affect the production.
Three. Definition of Secondary Air
The secondary air is cooled air, which is added to the kiln system as the second air and used for fuel combustion. Its function is to heat pulverized coal and supplement oxygen. Increasing the secondary air temperature is beneficial to the ignition of pulverized coal and the flame propagation rate.
Four. Influence of Secondary Air on Rotary Kiln System
The stability of the secondary air is very important to the production of the rotary kiln system. Properly increasing the secondary air temperature is beneficial to the combustion of fuel, but it has a greater impact on the shape of the flame. When the secondary temperature increases, the secondary air volume and wind speed also increase. The flame can also be adjusted to rise or fall. It is more conducive to the calcination of raw meal.
