ONE-STEP DIRECT CATALYTIC SEWAGE SLUDGE LIQUEFACTION OVER A SULFIDED METAL CATALYST

Sewage sludge residue from wastewater treatment could be transformed to more valuable products. Direct one-step catalytic liquefaction tests were performed to produce synthetic crude and other compounds such as ethylene or propylene from the organic part of the industrial sewage sludge. The catalyst was a commercial metal sulfided hydrocracking NiW/SiO2-Al2O3 material. The reaction was performed with 20 g of dried sewage sludge, 50 g of tetralin and 2 g of catalyst in a batch reactor at 420 degrees C for 1 h (P-H2=5 MPa at room temperature). The feedstock and products were analysed (GC/FID-TCD, elemental H, C, N, S% analysis, TGA (O-2 and N-2) and ATR-FTIR). For the gases, the main products were ethane, methane, CO2 and CO. Liquid products in the boiling range of 50-390 degrees C were obtained. Tetralin was not an inert solvent implying a lower yield to liquids compared to the standard direct coal liquefaction.