1. Pulverized coal combustion process

• Drying and milling: grind coal into fine powder (typical target: >70% passing 200 mesh, varies by furnace type)
• Primary air conveying: coal powder and primary air form a gas-solid two-phase flow into the burner
• Ignition and volatile combustion: volatiles release and burn first
• Char combustion and burnout: solid carbon reacts on the surface until burnout

2. Typical equipment and arrangements

• Straight-flow pulverized coal burners, swirl pulverized coal burners
• Wall-fired, opposed-fired, tangential/corner-fired furnace organization
• Industrial kilns can also use coal powder injection systems with coal feeding, milling, separation, dust removal, explosion protection, and interlocks

3. Characteristics of pulverized coal combustion
   Advantages:

• Easier complete combustion than lump coal, higher heat intensity, wide turndown range
• More uniform temperature field (with proper air distribution)

Challenges and risks:

• High dust explosion and ignition risk; requires strict inerting/ventilation/explosion-proof design
• Ash causes slagging, wear, and higher fly ash treatment cost
• Stricter requirements on burner and furnace residence time: insufficient burnout raises fly ash carbon and reduces efficiency