Degradative solvent-catalyzed extraction of sewage sludge.

ABSTRACT

It is necessary for the further development of sludge degradative solvent extraction (DSE) to significantly increase the bio-oil yield and adjust its composition. In this study, the effects of MCM-41, HZSM-5, and SSZ-13 on the physical properties, yield, and composition of bio-oil were compared. Results show that all three catalysts effectively promote the conversion of volatiles in the residue to the heavy component (heavy-s). The addition of MCM-41 improved the yieldof both the light component (light-s) and heavy-s. Their yields increased from 8.11% and 20.47% to 14.39% and 29.18%, respectively. Its all-silicon structure and weak acidity have no significant effect on the composition of the bio-oil. HZSM-5 addition increases the light-s yield to 25.58%. Its MFI structure and proper acidity are beneficial to the formation of aromatic hydrocarbons and olefins, while effectively reducing oxygenates. SSZ-13 increases the heavy-s yield to 27.89%, and promoted the formation of nitrogen-containing compounds significantly.