An experimental investigation of methanol combustion in low temperature supercritical water

Methanol combustion in supercritical water was systematically investigated at iso-thermal iso-baric conditions using the Eastern Michigan University Supercritical Batch Reactor. The nominal mixture was 1.5% methanol by volume with an oxygen equivalence ratio of 0.22 and a total density of 193 mg/mL; reaction times were 8–30 min with temperatures from 375° to 475 °C. The experimental observations here provide new comprehensive benchmark data for methanol oxidation near the critical point, including an evaluation of wall effects on chemical kinetics. Excellent repeatability demonstrates the effective function of the new experimental facility. The system was modeled using a custom kinetics solver and an existing chemical kinetic mechanism, with genetic optimization used for sensitivity analysis. Modeling results validate the general accuracy of an established chemical kinetic mechanism in lower temperature supercritical water and support a rate reduction for CH3OH + OH/HO2 = CH2OH + H2O/H2O2 reactions below existing uncertainty limits at these conditions