Supercritical water partial oxidation mechanism of ethanol

Abstract

In recent years, supercritical water as a green reaction medium to convert organic matter to produce hydrogen has attracted significant attention. At present, the mechanism of the supercritical water partial oxidation (SCWPO) process is still unknown when complete gasification is achieved. In this paper, a detailed mechanism for SCWPO of ethanol was proposed by establishing a novel kinetic model with a wide reaction temperature range. This model described the formation and consumption of gas products (H2, CO, CH4, and CO2) from ethanol by partial oxidation in the supercritical water environment through nine reactions. The results showed that the dehydrogenation and pyrolysis of ethanol were the main ways to generate H2 in the early stage, and the water-gas shift reaction had the most significant impact on hydrogen production in the later stage. The hydrogenation reaction of the intermediate product ethane was a key step for complete conversion into combustible gas products. The steam reforming reaction of a large amount of CH4 produced by ethanol and intermediate product will become the rate-determining step for hydrogen production.