Patent ID: 8518219
Filing Date: 2013-08-27
Classification: C02F,C10G

Abstract:
1. A multi-stage process for the treatment of sewage sludge comprising the steps of: (a) drying sewage sludge waste to reduce a water content of the sewage sludge waste to below about 15% so as to result in dried sewage sludge; (b) mixing the dried sewage sludge with a first solvent medium so as to result in a slurry; (c) subjecting the slurry to a thermo-chemical liquefaction process in the presence of a second solvent medium at a temperature ranging from about 275° C. to about 375° C. and a pressure of up to about 10 atmospheres so as to result in a first slurry product comprising a gaseous product, a liquid product and a solid product; (d) separating the first slurry product into a second slurry product and a condensable gas, wherein the condensable gas comprises water and other liquid fractions boiling out at up to about 250° C.; (e) steam stripping the second slurry product at a temperature ranging from about 250° C. up to about 400° C., separating therefrom liquid products from solid residue so as to result in mix vapors and solid char; (f) cooling and separating the mix vapors so as to obtain two separate streams of an oil product and water; and (g) subjecting the oil product to vacuum distillation so as to recover oil fractions having a boiling temperature between about 250° C. to about 350° C. and oil fractions having a boiling temperature above about 350° C.