Kinetic Study on Pyrolysis and Oxidation of CH₃Cl in Ar/H₂/O₂Mixtures

Abstract

The thermal decomposition of methyl chloride in hydrogen/oxygen mixtures and argon bath gas was carried out at I atmosphere pressure in tubular flow reactors. CH,CI, intermediate, and final products were analyzed over the temperature range 1098 to 1273 K, with average residence times of 0.2 to 2.0s.A detailed kinetic reaction mechanism based upon fundamental thermochemical and kinetic principles, Transition State Theory and evaluated literature rate constant data was developed to explain and understand the data. The model results show good fits to methyl chloride, intermediate, and final products species profiles with both temperature and time of reaction. The model also fits the data on HCI inhibited oxidation of CO presented in the companion paper by Roesler et al. Reactions showing high sensitivity to inhibitionof CO oxidation were identified. The results indicate that the reaction OH + HCI -H,O + Cl is an important source of OH loss. This decrease in OH strongly effects CO burnout. The reactions of CO + HO, -CO, + OH and CO + ClO -CO, + CI become important pathways for production of CO 2 in the fuel rich system when high levels of HCl are present. The termination reaction CI + H0 2 _ HCI + 0, is also important to inhibition in the lower temperature regime of this study. We also report on CIO radical reactions with methyl and chloromethyl radicals which form formaldehyde and chlorofonnaldehydes that are important to CO formation.

Experimental study on CCl4/CH4/O2/N2 oxidation

“…The Cl attack enhances CH 4 conversion and some organic intermediates are produced [26]: It is shown that the pollutants emission may be lower if CH 4 is combusted first and then CCl 4 is injected into the high temperature flue gas, rather than directly mixing the CCl 4 with CH 4 before combustion, which means a two-stage combustion mode. At the first stage, CH 4 will be oxidized to CO 2 and H 2 O, and the inhibition of chlorine on CH 4 oxidation could be eliminated.…”

Numerical and experimental study on silica generating counterflow diffusion flames

“…Numerical calculations were conducted to model silica generation and possible changes in flame structure with the silica generation. Reaction mechanism consists of 19 species and 43 reaction steps including 19 oxyhydrogen reactions [15] and 19 reactions related to chlorinated species [16] as well as silica formation reactions via oxidation [17] and hydrolysis [18] of SiCl 4 , as listed in Table 2. Governing equations and numerical schemes have been presented in Lee and Chung [19] and Smooke [20].…”

Survey of Rate Coefficients in the C-H-Cl-O System

“…(See, for example, , Chang and Senkan 1989, Fisher et al 1990, and Ho et al 1992 For such modeling studies, however, it is required that the rate parameters of a large number of reactions be estimated. Although estimation in itself is not undesirable, as there will always be more reactions in such complex systems than resources available to study them individually in isolated experiments, experimental rate measurements on reactions of chlorinated species at combustion temperatures serve as vital references to assess the validity of predictions and to calibrate theoretical methods.…”