Numerical analysis on influence of hydrogen peroxide (H2O2) addition on the combustion and emissions characteristics of NH3/CH4-air (O2/N2)/ H2O2 mixture

Abstract

In this work, extensive chemical kinetic modeling is performed to analyze the combustion and emissions characteristics of premixed NH3/CH4–O2/N2/H2O2 mixtures at different replacement percentages of air with hydrogen peroxide (H2O2). This work is comprehensively discusses the ignition delay time, flame speed, heat release rate, and NOx & CO emissions of premixed NH3/CH4–O2/N2/H2O2 mixtures. Important intermediate crucial radicals such as OH, HO2, HCO, and HNO effect on the above-mentioned parameters is also discussed in detail. Furthermore, correlations were obtained for the laminar flame speed, NO, and CO emissions with important radicals such as OH, HO2, HCO, and HNO. The replacement of air with H2O2 increases flame speed and decreases the ignition delay time of the mixture significantly. Also, increases the CO and NOx concentration in the products. The CO and NOx emissions can be controlled by regulating the H2O2 concentration and equivalence ratios. Air replacement with H2O2 enhances the reactions rate and concentration of intermediate radicals such as O/H, HO2, and HCO in the mixture. These intermediate radicals closely govern the combustion chemistry of the NH3/CH4– O2/N2/H2O2 mixture. A linear correlation is observed between the flame speed and peak mole fraction of OH + HO2 radicals, and 2nd degree polynomial correlation is observed for the peak mole fraction of NO and CO with HNO + OH and HCO + OH radicals, respectively.