Process for the treatment of organic waste and product obtained thereof

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.

2. A multi-stage process according to claim 1 wherein the second solvent medium used in the thermo-chemical liquefaction process of step (c) is a liquid product with a boiling point above about 350° C.

3. A multi-stage process according to claim 1 wherein the first solvent medium and the second solvent medium are the same.

4. A multi-stage process according to claim 1 further comprising the step of:

(h) recirculating the oil fractions having a boiling temperature above about 350° C. to the thermo-chemical liquefaction process of step (c) for use as the second solvent medium.

5. A multi-stage process according to claim 4 wherein the recirculated solvent medium serves as a hydrogen donor in step (c).

6. A multi-stage process according to claim 1 wherein step (e) is carried out at a temperature ranging from about 300° C. up to about 350° C.

7. A multi-stage process according to claim 1 wherein in step (a) the sewage sludge waste is dried to reduce the water content of the sewage sludge waste to below about 12%.

8. A multi-stage process according to claim 1 wherein in step (b) a ratio of solvent medium to dried sewage sludge is between about 0.75:1 and about 1.5:1.

9. A multi-stage process according to claim 1 wherein in step (b) a ratio of solvent medium to dried sewage sludge is about 1:1.

10. A multi-stage process according to claim 1 wherein step (e) is carried out at a temperature of about 350° C.

11. A multi-stage process according to claim 1 wherein step (e) is carried out by mix of water steam and inert gas.

12. A multi-stage process according to claim 1 wherein the condensable gas from step (d), the solid char from step (e) and the oil fractions having a boiling temperature above about 350° C. from step (g) are combined and employed as a combustion source in heat energy generation, wherein the energy is utilized in the multi-stage process.

13. A multi-stage process according to claim 1 wherein the oil product obtained in step (g) is a fuel product comprising oil distillates having a boiling temperature up to about 250° C. (Light Oil) and oil distillates having a boiling temperature between about 250° C. to about 350° C. (Middle Distillate).

14. A multi-stage process according to claim 1 wherein the sewage sludge waste is composed of organic materials.