Kinetic study of the pyrolysis of tetrachloroethylene in a hydrogen rich environment

Experiments on pyrolysis of C₂Cl₄ with hydrogen in argon bath gas (C₂Cl₄: H₂: AR=0.5:7:92.5) were performed in a laboratory scale flow reactor, to determine reaction paths and kinetic parameters, plus to observe hydrogen as a source to convert chlorocarbons into hydrocarbons and HCl. The reaction was carried out at 1 atmosphere total pressure in the tubular flow reactor, over temperature ranges from 575 to 850 °C, with average residence times in the range of 0.3 to 1.2 s. The major reaction products were C₂HCl₃, CH₂CCl₂, C₂H₆, C₂H₄ and HCl. Trace intermediates including CH₄, C₂H₂, C₃H₆, C₃H₄, C₄H₈, C₄H₆, C₄H₄, C₂H₃Cl, C₂HCl, trans-CHClCHCl, cis-CHClCHCl C₂Cl₂ and aromatic compounds were found. The equation for overall loss of C₂Cl₄ (k (s⁻¹)) was 1.35×10⁶exp(−27055/RT). This study shows that C₂H₄ became the major product for reaction temperatures higher than 700 °C, and became one of the final products together with HCl.A detailed kinetic mechanism consisting of 202 elementary reactions with 59 species was developed to model the results obtained from the experiments. Sensitivity analyses were performed to rank the significance of each reaction in the mechanism. Modeling and sensitivity analysis revealed that C₂Cl₄+H→C₂HCl₃+Cl, C₂Cl₄+H→C₂Cl₃+Cl, and C₂Cl₄→C₂Cl₃+Cl are the primary reactions for the decomposition of C₂Cl₄.