The Simulating Of Gas Oxygen-Enrichment Combustion In Tunnel Kiln

Tunnel kiln is the continuity of the firing device that is used to produce inorganicnon-metallic materials, in which the firing zone is the main structure for firing. Using themethod of numerical simulation of computer simulating gas oxygen-enriched combustionprocess in the firing zone of tunnel kiln, doing the research how to reduce energyconsumption and pollution in industrial production process by using oxygen-enrichedcombustion in tunnel kiln technology, which can provide guidance to the actual kilnstructure optimization and the operation control, and laid theoretical basis tooxygen-enriched combustion technology applied in tunnel kiln.This paper studies an open-flame ceramic tunnel kiln structure and the thermal process,using the fluid analysis software FLUENT to establish the combustion model of the firingzone in tunnel kiln, performing3-d numerical simulation of the tunnel kiln firing zone.The results show that，when oxygen mass fraction increases from23%to38%:（1） Thekiln temperature field is more and more even. When tunnel kiln production keep fixed,oxygen-enriched combustion temperature of kiln crown makes reduced, extending theservice life, and also reducing temperature difference between up and down in the tunnelkiln.（2） When fuel and fuel types keep fixed, the flame temperature also gradually rise, andtemperature rising rate decreased; When there is the same oxygen-enriched atmosphere, theflame temperature of gas with high calorific value is higher than fuel with low calorificvalue,which shows that fuel with high calorific value burns more completely.（3）Disturbance of the gas inside the kiln also are more intense and at the same time; Whentype of fuel and fuel keep fixed, velocity of smog exit reduce gradually; When burning thesame oxygen-enriched atmosphere, as the input overall calorie is same, whatever, outletflow of fuel with high calorific value is lower and lower.（4） NO concentration in exportsection increases gradually, and the trend of increase gradually reduce,among them, NOand Thermal NO keep the same concentration change trend, and Prompt NO contentincreases more and more.（5） There are certain corresponding relation between NOconcentration field and velocity field.In the smaller speed area, NO concentration is higher, therefore, should try to speed up disturbing degree of the gas inside kiln to inhibit thegeneration of NO.（6） The concentration of CO of blast furnace gas significantly reduces;Generator gas CO concentration increases, but the trend of increase significantly is not asthe reduce trend of blast furnace gas. In the same atmosphere, concentration of CO ofgenerator coal gas with high calorific value is lower than blast furnace gas with lowcalorific value; CO₂concentration increases. Advised to keep oxygen mass fraction at28%,it can guarantee the lower output of CO and the higher output of CO₂.（7） Reduced theproducts’ comprehensive energy consumption of per unit of production in tunnel kiln, andwhen the oxygen mass fraction is38%, dissipated energy consumption is about35%lessthan conventional air burning.