Supercritical water gasification of oil-containing wastewater with a homogeneous catalyst: Detailed reaction kinetic study.

Supercritical water gasification (SCWG) is a promising technology for oil-containing wastewater treatment. This paper aims to establish a reaction kinetic model to provide better guidance for optimal industrial reactor design. The model is developed based on the experimental results obtained from K 2 CO 3 -catalyzed SCWG of diesel (the model compound of oil containment in wastewater) at various conditions of 500–650 °C and 15.23–64.45 s. Then the model validation by using the experimental data from other conditions. The validation results showed that the kinetic model can predict the gas concentration with an acceptable deviation. Afterward, the indicators of carbon gasification efficiency and gas yield versus residence time are predicted. The results show that the required residence time for the complete gasification is varied from 214.2 to 2150.8 s when the temperature changes from 500 to 650 °C. Moreover, the reaction rate analysis result indicates that the two reactions contributed most to the hydrogen production are the forward water-gas shift and the reverse CO methanation reaction. Additionally, the sensitivity analysis result reveals that the hydrolysis reaction of diesel has a significant influence at the initial stage, while the CO and CO 2 methane reactions play a vital role at the late stage for gas production. [Display omitted] • A kinetic model with 13 reactions of SCWG of oil-containing wastewater is developed. • Residence time of 239.2 s for complete gasification under 650 °C is predicted. • Reaction rates for gases production and consumption are analyzed. • The hydrolysis reaction of diesel has a significant influence at the initial stage. [ABSTRACT FROM AUTHOR]