Insights into carbon monoxide oxidation in supercritical H2O/CO2 mixtures using reactive molecular dynamics simulations

MJ Fan and YJ Lu, JOURNAL OF SUPERCRITICAL FLUIDS, 189, 105727 (2022).

DOI: 10.1016/j.supflu.2022.105727

Carbon monoxide is an important intermediate in supercritical water oxidation processes. Carbon monoxide oxidation in supercritical H2O/CO2 mixtures was investigated using reactive molecular dynamics simulations. The results show that CO mainly converts into CO2 through the reaction CO + OH & RARR; HOCO & RARR; CO2 + H. The intermediate HOCO can also react with OH or O2 to form CO2. The overall activation energies of CO oxidation in the supercritical medium range from 125.3 & PLUSMN; 4.0-159.4 & PLUSMN; 3.6 kJ/mol, which are roughly consistent with the experimental results. Supercritical water not only provides reactive free radicals for CO conversion but also acts as a third body to induce some chemical events. The high concentration of CO2 inhibits the production of OH but highlights the oxidizing action of O and HO2. Oxygen increases the amounts of OH and HO2 through the reaction H2O + O2, thereby promoting the conversion of CO.

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