Bio-oil from thermo-chemical hydro-liquefaction of wet sewage sludge.

The present work demonstrates the influence of experimental conditions such as weight ratio of sewage sludge to water (1/0-1/15), reaction temperature (200-350°C), initial H2 pressure (2.0-11.0MPa), residence time (10-100min) and type of catalysts (Na2CO3, Raney nickel, FeSO4, MoS2) on hydro-liquefaction process of sewage sludge. High amount of water improves the hydro-liquefaction process of sewage sludge by increasing the yield of bio-oil and the total conversion. The highest yield of bio-oil (47.79 wt.%) from sewage sludge was obtained with initial H2 pressure 5.0MPa, reaction temperature 300°C, and residence time 40min. Under these experimental conditions, using weight ratio of sewage sludge to water 1/5, catalyst (FeSO4) - 5 wt.% of dry SS, mixing speed 350rpm the obtained bio-oil had the highest energy recovery (69.84%), total conversion (70.64%) and its calorific value was 35.22MJ/kg.