First-principles thermochemistry for the combustion of TiCl4 in a methane flame

This work presents thermochemical data for many of the intermediates in the early stages of the combustion of titanium tetrachloride (TiCl4) in the presence of residual species from a methane flame. An algorithm developed for previous work is employed to ensure that all possible species are considered, reducing the probability of neglecting important species. Thermochemical data and enthalpies of formation are calculated for 141 new species using density functional theory (DFT) and statistical mechanics. Equilibrium calculations are performed to try to identify which intermediates are likely to be most prevalent in the high temperature industrial process. The 10 species with the highest equilibrium compositions are identified and presented in the paper. These species, TiC(l)3OH, TiCl2OH, TiCl(OH)(2), TiOOH, TiOClOH, TiClOH, TiO(OH)(2), TiHOOH, TiCl2(OH)(2), and TiClHOH, along with the original TixOyClz species are likely to be the most important species involved in the kinetic model. Data for the remaining species is provided as Supplementary data. The abundance of TiiOjClkHl species is high considering the low amount of hydrogen present in the simulation and they are likely to have a significant impact on the process, something that has not been recognized in previous publications. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.