Numerical study on supercritical water partial oxidation of ethanol with auto-thermal operation

Abstract

Supercritical water partial oxidation (SCWPO) is a low-carbon, non-polluting organics processing technology with great potential for development. This technology could convert ethanol into hydrogen and energy efficiently. However, conventional SCWPO reactors rely on external heating and thus have the disadvantages of harsh wall material requirements and low system efficiency. There is a lack of research on SCWPO reactors with auto-thermal operation. A numerical study on SCWPO of ethanol with auto-thermal operation under the adiabatic wall condition was conducted. The results of the SCWPO on ethanol were analyzed and compared for different parameters. It was found that the internal field distribution of the reactor for the adiabatic wall condition was significantly different from the thermostatic wall condition. Increasing the ethanol concentration reduced the equivalent ratio of oxidant (ER) required for the reactor to reach the auto-thermal state. Both higher preheated water temperature and longer reactor length could enhance the effect of the SCWPO of ethanol. When the reactor length was 4 m and the preheat water temperature was 600 °C, carbon gasification efficiency (CE) could reach 99.0%. This numerical study could serve for reactor scale-up and system optimization of SCWPO with auto-thermal operation.