Gasification characteristics and sulfur migration mechanism during supercritical water partial oxidation of 2-methylthiophene

Abstract

Supercritical water partial oxidation (SCWPO), as a clean and efficient energy conversion technology, offers new insights for the clean treatment of thiophene compounds, which are a significant source of potential pollutants. However, the detailed reaction mechanism of thiophene compounds in the SCWPO process is still unclear. Therefore, the effects of parameters on gasification characteristics and sulfur migration were investigated in the quartz tube reactor during the SCWPO of 2-methylthiophene (2-MT). The results demonstrated that extending the reaction time, increasing the reaction temperature, and reducing the feed concentration favored gaseous product generation. The SCWPO environment with the low equivalent ratio (ER) was favorable for the generation of hydrogen-rich gas. When the conditions were 750 °C, 4 wt%, 15 min, ER = 0.2, the highest H2 yield was 18.59 mol kg−1. With the addition of oxidants, the SCWPO environment promoted the conversion of sulfur from S-2, S-o to S+4, S+6. This conversion reduced the sulfur content in the gas, making it stored in a more environmentally friendly form. Notably, the presence of SOx was not detected during the SCWPO process. Finally, a detailed reaction mechanism for the SCWPO of 2-MT was proposed based on the comprehensive analysis of experimental products.