Production of partially refined waste glycerol
View Patent ↗The disclosure relates to a novel glycerol purification process that produces partially refined waste glycerol for a variety of industrial applications. The disclosure encompasses a salt-containing partially refined glycerol composition that is suitable as a fermentation grade glycerol.
1. A process of producing partially refined waste glycerol by refining crude glycerol containing organic impurities, said process comprising:
deoiling using a hydrophobic solvent to extract organic impurities;
dewatering by drying at an elevated temperature; and
desalting using a polar solvent to precipitate salt.
2. A process of producing partially refined waste glycerol by refining crude glycerol containing organic impurities, said process comprising:
subjecting crude glycerol to a hydrophobic solvent to produce a mixture of crude glycerol and hydrophobic solvent; and
separating the mixture of crude glycerol and hydrophobic solvent to produce a deoiled (DO) glycerol and a phase containing hydrophobic solvent and organic impurities.
3. The process of claim 2 , further comprising the step of drying said DO glycerol to produce a deoiled and dewatered (DOW) glycerol.
4. The process of claim 3 , further comprising the steps of:
subjecting a polar solvent to said DOW glycerol to produce a mixture of polar solvent and DOW glycerol and precipitating a salt from the mixture of polar solvent and DOW glycerol; and
separating the mixture of polar solvent and DOW glycerol into a light phase containing a deoiled, dewatered and desalted (DOWS) glycerol and the polar solvent and a heavy phase containing the salt.
5. The process of claim 4 , further comprising the step of removing the polar solvent from the light phase to produce a purified DOWS glycerol.
6. The process of claim 4 , further comprising the step of partially evaporating the DOW glycerol before subjecting it to the polar solvent.
7. The process of claim 2 , further comprising the steps of:
subjecting a polar solvent to said DO glycerol to produce a mixture of polar solvent and DO glycerol and precipitating a salt from the mixture of polar solvent and DO glycerol; and
separating the mixture of polar solvent and DO glycerol into a light phase containing a deoiled and desalted glycerol and the polar solvent and a heavy phase containing the salt.
8. The process of claim 7 , further comprising the step of drying said deoiled and desalted glycerol to produce a deoiled, desalted and dewatered (DOWS) glycerol.
9. The process of claim 5 , wherein said DOWS glycerol is a fermentation grade glycerol.
10. The process of claim 2 , wherein said hydrophobic solvent is selected from the group consisting of triacylglyceride, alkane, alkene, acetate, and fatty acid alcohol ester.
11. The process of claim 10 , wherein said triacylglyceride is vegetable oil.
12. The process of claim 10 , wherein said acetate is butyl acetate.
13. The process of claim 10 , wherein said alkane is hexane.
14. The process of claim 2 , wherein said organic impurities are oil-soluble.
15. The process of claim 2 , wherein said DO glycerol comprises less than about 195 ppm oil-soluble organic impurities.
16. The process of claim 3 , wherein said DOW glycerol comprises less than about 0.5 percent water.
17. The process of claim 4 , wherein said polar solvent is an alcohol.
18. The process of claim 17 , wherein said alcohol is isopropanol or butanol.
19. The process of claim 5 , wherein removing the polar solvent is done by flash evaporation.
20. The process of claim 9 , wherein said fermentation grade glycerol is salt-containing glycerol.
21. The process of claim 20 , further comprising the step of tailoring said salt content of said fermentation grade glycerol to between about 0.05 to about 8.2 percent salt.
22. The process of claim 20 , further comprising the step of tailoring said salt content of said fermentation grade glycerol to between about 0.05 to about 3.5 percent salt.
23. The process of claim 20 , further comprising the step of tailoring said salt content of said fermentation grade glycerol to between about 0.05 to about 1.0 percent salt.
24. The process of claim 2 wherein the separation occurs by at least one of gravity decantation, hydrocyclone separation, and centrifugal separation.
25. The process of claim 2 further comprising the step of heating the mixture of crude glycerol and hydrophobic solvent to between about 20° C. to about 95° C.
26. The process of claim 2 further comprising the step of heating the mixture of crude glycerol and hydrophobic solvent to between about 55° C. to about 65° C.
27. The process of claim 2 further comprising the step of mixing the mixture of crude glycerol and hydrophobic solvent for between about 5 minutes to about 30 minutes.
28. The process of claim 3 wherein the drying occurs at between about 60° C. to about 130° C.