Kinetic study of chlorine behavior in the waste incineration process

The waste incineration atmosphere was simulated as HCl/H2O/O2/CO2/N2 in order to experimentally study chlorine behavior as temperature ranges from 1173 to 1473 K and residence time varies. The results show that Cl radicals, produced by the decomposition of HCl at high temperature, mainly recombine to form Cl2 and HCl at the quenching section. It was found that temperature, residence time, cooling rate and feeding gas composition influence Cl2 concentration. To thoroughly understand this reaction system, a kinetic model was developed and validated against experimental results. The key reactions and main pathway were found out with the use of sensitivity and rate of production analysis (ROP). The reaction HCl + O2 → Cl + HO2 was shown to initiate the reaction system, and it was found that a significant amount of Cl2 was simultaneously produced by the following high temperature reaction: Cl + HOCl → Cl2 + OH. In the cooling process, the main consumption reactions of Cl radicals were H2O + Cl → HCl + OH, OH + Cl → HCl + O and Cl + Cl + M → Cl2 + M. Among these, the first two reactions can be used to explain the effect of H2O on the concentration of Cl radical at high temperature. In addition, the influence of the quenching rate on the distribution of chlorine was found to occur because of the varying effects that temperature change causes to the different Cl radical consumption reactions.