Numerical Simulation of a Reactor Containing Hydrothermal Flame for Supercritical Water Oxidation

摘要

A model of supercritical water oxidation (SCWO) reactor containing hydrothermal flame as an internal heat resource has been developed using a numerical simulation method. Oxygen and methanol solution are injected into the reactor simultaneously to generate the hydrothermal flame at 25MPa. The methanol solution temperature has been varied from 300 to 500℃ and methanol mass fraction from 5 to 20%. The initial oxygen temperature has been fixed at 500℃. An Arrhenius law and the Eddy Dissipation Concept (EDC) have been used to simulate the methanol combustion reaction. Several features of the fluid field of the flame, temperature, methanol mass fraction, oxygen mass fraction, streams function, and Arrhenius reaction rate contours, have been depicted. Moreover, the effect of inlet temperature and concentration of methanol on the temperature profile of the reactor axis has also been discussed. Increasing the inlet temperature of methanol solution from 300 to 500℃ enhanced the global reactor temperature from 1198 to 1309℃ accordingly. Furthermore, with the methanol concentration diminished, the flame height became shorter and the global reactor temperature was also diminished consequently.