Hydrothermal decomposition of thiophene derivatives in subcritical and supercritical water with alkali was studied to enhance desulfurization using a new on-site upgrading technology. Benzothiophene (BT), dibenzothiophene (DBT), and derivatives could be decomposed by hydrothermal reaction with alkali in a temperature region where thermal decomposition was difficult. The ease of decomposition was influenced by the type and concentration of the alkali solution. Decomposition in KOH solution was the most complete, and occurred at a certain alkali concentration. The reaction was sensitive to the pressure in supercritical water. Moreover, the reaction products of hydrothermal decomposition obtained differed to those by the published HDS method. The mechanisms of decomposition were different and hydrothermal decomposition was preceded by ionic reaction. The ease of decomposition of BT and DBT was influenced by the molecular structure, similar to the trends seen in HDS.
- Subcritical water
- Supercritical water
ASJC Scopus subject areas
- Fuel Technology
- Energy Engineering and Power Technology