There are two types of pulverized coal burners: swirl type and direct flow type. Let's follow the editor of Burner MOCO to have a simple understanding!
1. Swirl pulverized coal burner: mainly composed of primary air cyclone, secondary air adjustment baffle (swirl blade or volute) and primary and secondary air nozzles. It can be arranged on the front wall, side walls or front and back walls of the combustion chamber. The air conveying the pulverized coal is called primary air, which accounts for about 15-30% of the total air volume required for combustion. The pulverized coal-air mixture is injected into the combustion chamber through the primary air nozzle of the burner. The other part of the air required for combustion is called secondary air. After the secondary air passes through the adjusting baffle of the combustor (swirl blade or volute), it forms a rotating airflow, and merges with the primary air at the exit of the combustor to form a rotating jet. The negative pressure formed in the center of the jet draws high-temperature smoke to the root of the flame. This part of high-temperature flue gas is the main heat source for pulverized coal ignition. The expansion cone of the primary air outlet can increase the diffusion angle of the primary air to enhance the entrainment of high-temperature smoke.
2. Direct-flow pulverized coal burner: generally composed of several groups of primary and secondary air nozzles arranged along the height, arranged on each corner of the combustion chamber. The center line of the combustor is tangent to an imaginary circle in the center of the combustion chamber, so a horizontally rotating updraft can be formed in the combustion chamber. The primary and secondary air nozzles of each group of direct-flow burners are dispersedly arranged to meet the requirements of stable and complete combustion of different coal types, and sometimes it is also considered to reduce the amount of nitrogen oxides generated.
The above is the editor of Burner MOCO: a brief introduction to the relevant knowledge of pulverized coal burners.