Development and Validation of a Cost-Efficient Reduced Kinetic Mechanism for Coke Oven Gas Combustion Aim for Blast Furnace Applications

A detailed reduced kinetic mechanism (RD25) has been developed for COG combustion simulations, aiming to be applied in a realistic 3D blast furnace model at a reasonable cost and with acceptable accuracy. The reduced mechanism consists of 25 species and 136 reactions and was validated against experiments using simulation constructed from various existing literature-based burners. Moreover, the reduced mechanism was integrated into a numerical model based on a lab-scale jet-in-coflow (JIC) burner that is able to operate in a wide range of combustion regimes for comparison with the experiment. The burner was used to experimentally burn a ternary COG fuel obtained from a realistic BF iron-making plant. The COG combustion was tested under a varying, freely propagating flame from laminar to turbulence. The reduced mechanism demonstrated excellent performance in predicting COG laminar flame speed under standard operating conditions, with average errors of 4.66%. The computational cost of the reduced mechanism was able to reduced by approximately 50% compared to the original mechanism, with a minor compromise in accuracy levels. In predicting COG flame characteristics and blowout limits across a wide range of combustion regimes and mixture compositions, the reduced mechanism performed much better than a widely used 4-step global mechanism (GB7). The percentage errors in blowout velocities predicted by RD25 were 7.14%, 12.61%, and 13.38%, respectively, compared to 11.9%, 39.64%, and 35.33% in GB7.