Liquid fuel production from sewage sludge by catalytic conversion using sodium carbonate

For the production of liquid fuels and as a means of pollution control, sewage sludge was directly converted into heavy oils. The sewage sludge, having a moisture content of 75 wt %, was heated under pressurized nitrogen over the temperature range 250–340 °C in the presence of sodium carbonate. The yields and properties of the heavy oil produced depended strongly on the catalyst loading and reaction temperature. Liquid fuels having heating values of ≈ 33 MJ kg − 1 were obtained in 50 wt % yields on an organic basis. The energy balance of this liquefaction process is briefly discussed.