Process for purifying feedstock comprising fatty acids

Patent metadata

Field	Value
Publication number	US-10947478-B2
Application number	US-201916713204-A
Country	US
Kind code	B2
Filing date	Dec 13, 2019
Priority date	Dec 14, 2018
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

The present invention relates to process for purifying renewable feedstock comprising at least one acidulated soap-stock, wherein said process comprises the steps, where the renewable feedstock comprising at least one fatty acid is treated in a treating step with an aqueous medium, and a first stream comprising water and a second stream comprising fatty acids are obtained, and the second stream is obtained as purified renewable feedstock.

First claim

The invention claimed is:

1. A process for purifying renewable feedstock comprising at least one fatty acid, wherein said process comprises the steps,
pretreating the renewable feedstock comprising at least one fatty acid at a temperature of 90-145° C. and under a pressure of 0.1-10 bar (abs), with an aqueous medium comprising an acid selected from sulfuric acid and C1-C10 organic acids, wherein the ratio of the renewable feedstock to the aqueous medium is from 1:5 to 5:1, to provide a first-stage aqueous stream and a first-stage oil stream; and
treating the first-stage oil stream with water, at a temperature from 150 to 210° C., under a pressure from 5 to 70 bar (abs), where the ratio of the first-stage oil stream to the water is from 1:5 to 5:1, respectively, to provide a first stream comprising water and a second stream comprising oil, and the second stream is obtained as purified renewable feedstock.

2. The process according to claim 1 , wherein the renewable feedstock comprising at least one fatty acid is selected from the group consisting of acidulated soap-stocks, fatty acid distillates from physical refining of plant oils or animal fats, distillers corn oil from ethanol production, waste cooking oils, lard, brown grease, trap grease, waste fats, low-grade oils, super critical water liquefaction oils, pyrolysis oils, plant oils, animal fats and combination thereof.

3. The process according to claim 2 , wherein the acidulated soap-stocks are selected from acidulated soaps obtained from chemical refining of plant material, acidulated soaps from chemical refining of plant oils, acidulated soaps from chemical refining of animal fats, acidulated soaps from pulp production.

4. The process according to claim 1 , wherein the purified renewable feedstock comprises not more than 10 mg/kg phosphorus, calculated as elemental phosphorus.

5. The process according to claim 1 , wherein the purified renewable feedstock comprises not more than 10 mg/kg of alkali metals, alkaline earth metals, metals of the groups VIIB and VIIIB of the Periodic table of elements, or combinations thereof, calculated as elemental metals, in total.

6. The process according to claim 1 , wherein the first stream comprising water comprises not more than 10 000 mg/kg total organic carbon.

7. The process according to claim 1 , wherein the purified feedstock comprises not more than 10 mg/kg calculated as elemental silicon.

8. The process according to claim 1 , wherein the purified renewable feedstock comprises not more than 10 mg/kg phosphorus, not more than 10 mg/kg silicon and not more than 10 mg/kg alkali metals, alkaline earth metals, metals of the groups VIIB and VIIIB of the Periodic table of elements, or combinations thereof, and the first stream comprising water comprises not more than 10 000 mg/kg total organic carbon.

9. The process according to claim 1 , wherein the aqueous medium comprises 0.01 to 3 wt % of the acid selected from sulphuric acid and C1-C10 organic acids, calculated based on the renewable feedstock comprising fatty acids.

10. The process according to claim 1 , wherein the C1-C10 organic acid is EDTA or C1-C6 organic acid selected from citric acid, formic acid, oxalic acid, acetic acid, butyric acid, valeric acid, caproic acid and propionic acid.

11. The process according to claim 1 , wherein the acid is sulphuric acid.

12. The process according to claim 1 , wherein the first-stage oil stream is treated at a temperature from 150 to 200° C., under a pressure from 5 to 30 bar (abs).

13. The process according to claim 1 , wherein in the pretreatment step the temperature is 95-140° C., and the pressure is 0.5-5.5 bar (abs).

14. The process according to claim 1 , wherein in the treating step, the temperature is 155-200° C., and the pressure is 6-25 bar (abs).

15. The process according to claim 1 , wherein the aqueous medium comprises not more than 3 wt % of organic compounds.

16. The process according to claim 1 , wherein the residence time is from 10 min to 12 hours.

17. The process according to claim 1 , wherein the pH of the first stream is in the range from 0 to 6.5.

18. The process according to claim 1 , wherein the second stream is fractionated to obtain a gaseous fraction, a light liquid fraction and a heavy liquid fraction.

19. The process according to claim 1 , wherein at least part of the first stream is recirculated to the aqueous medium.

20. The process according to claim 1 , wherein the carbon yield is at least 98%.

21. The process according to claim 2 , wherein the acidulated soap-stocks are selected from acid oils and crude tall oil.

22. The process according to claim 1 , wherein the purified renewable feedstock comprises not more than 5 mg/kg phosphorus, calculated as elemental phosphorus.

23. The process according to claim 1 , wherein the purified renewable feedstock comprises not more than 5 mg/kg of alkali metals, alkaline earth metals, metals of the groups VIIB and VIIIB of the Periodic table of elements, or combinations thereof, calculated as elemental metals, in total.

24. The process according to claim 1 , wherein the purified feedstock comprises not more than 5 mg/kg silicon, calculated as elemental silicon.

25. The process according to claim 1 , wherein the aqueous medium comprises 0.01 to 3 wt % of organic compounds.

26. The process according to claim 1 , wherein the residence time is from 10 min to 7 hours.

27. The process according to claim 1 , wherein no acid is added during the treating of the first-stage oil stream.

Assignees

• Upm Kymmene Corp

Inventors

• Björklöf Thomas
• Gutierrez Andrea

Classifications

• C11B13/005

  of residues of the fabrication of wood-cellulose (in particular tall-oil) · CPC title

• C11B3/04

  with acids · CPC title

• Y02P30/20

  using bio-feedstock · CPC title

• C11B3/001 Primary

  by a combination of two or more of the means hereafter · CPC title

• C11B13/00

  Recovery of fats, fatty oils or fatty acids from waste materials · CPC title