Oil production from garbage by thermochemical liquefaction

Garbage was converted directly into oil by thermochemical liquefaction for the recovery of energy in the form of liquid fuel. The garbage with a moisture content of about 90 wt% was prepared by mixing cabbage, boiled rice, boiled and dried sardine, butter, and the shell of short-necked clam. The mixture was heated under pressurized nitrogen at 250°, 300°, or 340°C for 0.1, 0.5, or 2 h, with or without sodium carbonate as a catalyst (0 or 4% on a dry solid basis). Oil yield and its properties strongly depended on catalyst addition and reaction temperature, while holding time showed no marked effect. Oil was obtained in the highest yield of 27.6% on an organic basis under the following conditions: catalyst addition, 4 wt%; temperature, 340°C; pressure, 18 MPa; and holding time, 0.5 h. The oil had a calorific value of 36 MJ kg−1 and a viscosity of 53,000 mPas at 50°C. Its carbon content, hydrogen content, nitrogen content and oxygen content were 73.6, 9.1, 4.6 and 12.7%, respectively.