KINETIC INTERACTIONS OF CO, NOX, AND HCL EMISSIONS IN POSTCOMBUSTION GASES

Postflame chemistry is governed largely by moist CO oxidation. During carbon monoxide burnout, trace amounts of many other pollutants formed in and/or surviving through the flame front may be present (e.g., SOx , NOx, HCl, and unburned hydrocarbons). The development of accurate ch emical models describing these final stages of pollutant destruction r equires evaluating the potential kinetic coupling effects that exist a mong these components. In the present investigation, the coupling betw een NO and HCl in a moist CO oxidation bath is considered. Experiments are performed in an atmospheric pressure flow reactor by perturbing t he CO/H2O/O-2 reaction system with trace amounts of NO and/or HCl for temperatures between 1000 and 1070 K and both stoichiometric (Phi = 1. 0) and fuel-lean (Phi = 0.1) mixtures. The experimental results are co mpared with predictions from a detailed kinetic model and analyzed by gradient sensitivity and reaction flux analyses. While the addition of the individual perturbing agents show accelerating or inhibiting char acteristics depending on the equivalence ratio and temperature, the co upling between NO and HCl generates considerable synergistic inhibitio n of the CO oxidation rate. Thus, accurate predictions of CO burnout i n practical systems, where trace quantities of HCl and NOx are present , can be achieved only if these kinetic interactions are considered.