Preheating combustion technology is a high-efficiency, clean combustion technology that modifies fuel before it enters the main combustion zone of a rotary kiln. Its core principle involves installing a preheating device upstream of the burner. This device uses high-temperature flue gas to heat the fuel-typically pulverized coal-to 800–900°C, facilitating pyrolysis and partial gasification. This process converts the fuel into high-temperature fuel before it is injected into the kiln for combustion.
This advanced combustion method offers three primary advantages:
- High Combustion Efficiency: The modified fuel burns extremely rapidly, producing a compact flame with a concentrated high-temperature zone. This effectively reduces fuel consumption per unit of product, lowering overall operational costs.
- Strong Flame Controllability: By precisely adjusting the burner's swirl number-with research indicating an optimal range of 0.2–0.8-operators can flexibly control flame shape, including length and width. A stronger swirl creates a central recirculation zone, which helps stabilize the flame and ensures consistent kiln operation.
- Low Nitrogen Oxide (NOx) Emissions: Because the combustion process is more concentrated and efficient, it creates a reducing atmosphere. As a result, NOx emissions in the flue gas are significantly reduced compared to traditional pulverized coal combustion, helping facilities meet stringent environmental regulations.
