Processes and apparatus for removal of fermentation inhibitors from biomass hydrolysates
View Patent ↗The disclosure provides a process for separating fermentation inhibitors from a biomass-derived hydrolysate, comprising: introducing a biomass-derived liquid hydrolysate stream to a stripping column; introducing a steam-rich vapor stream to the stripping column to strip fermentation inhibitors (such as acetic acid) from the liquid hydrolysate stream; recovering a stripped liquid stream and a stripper vapor output stream; compressing the stripper vapor output stream; introducing the compressed vapor stream, and a water-rich liquid stream, to an evaporator; recovering, from the evaporator, an evaporated liquid stream and an evaporator output vapor stream; and recycling the evaporator output vapor stream to the stripping column as the steam-rich vapor stream. Other variations utilize a rectification column to recover a rectified liquid stream and a rectification column vapor stream, and recycle the rectification column vapor stream to the stripping column as the steam-rich vapor stream.
1. A process for separating fermentation inhibitors from a biomass-derived hydrolysate, said process comprising:
(a) providing a biomass-derived liquid hydrolysate stream comprising a fermentation inhibitor;
(b) introducing said liquid hydrolysate stream to a stripping column;
(c) introducing a steam-rich vapor stream to said stripping column to strip at least a portion of said fermentation inhibitor from said liquid hydrolysate stream;
(d) recovering, from said stripping column, a stripped liquid stream and a stripper vapor output stream, wherein said stripped liquid stream has lower fermentation inhibitor concentration than said liquid hydrolysate stream;
(e) compressing said stripper vapor output stream to generate a compressed vapor stream;
(f) introducing said compressed vapor stream, and a water-rich liquid stream, to an evaporator;
(g) recovering, from said evaporator, an evaporated liquid stream and an evaporator output vapor stream; and
(h) recycling at least a portion of said evaporator output vapor stream to said stripping column as said steam-rich vapor stream, or a portion thereof.
2. The process of claim 1 , wherein said fermentation inhibitor is selected from the group consisting of acetic acid, formic acid, formaldehyde, acetaldehyde, lactic acid, furfural, 5-hydroxymethylfurfural, furans, uronic acids, phenolic compounds, sulfur-containing compounds, and combinations or derivatives thereof.
3. The process of claim 2 , wherein said fermentation inhibitor is acetic acid and wherein said stripped liquid stream has less than 10 g/L acetic acid concentration.
4. The process of claim 3 , wherein said stripped liquid stream has less than 5 g/L acetic acid concentration.
5. The process of claim 1 , wherein said water-rich liquid stream contains biomass solids that are concentrated in said evaporator.
6. The process of claim 5 , wherein said biomass solids are derived from the same biomass feedstock as said biomass-derived liquid hydrolysate.
7. The process of claim 1 , wherein said fermentation inhibitor is recycled to a previous unit operation for generating said biomass-derived liquid hydrolysate stream, to assist with hydrolysis or pretreatment of a biomass feedstock or component thereof.
8. The process of claim 7 , wherein said fermentation inhibitor includes acetic acid.
9. The process of claim 1 , wherein said process is continuous or semi-continuous, and wherein said stripping column is operated countercurrently.
10. The process of claim 1 , wherein said process is continuous or semi-continuous, and wherein said stripping column is operated cocurrently.
11. A process for separating fermentation inhibitors from a biomass-derived hydrolysate, said process comprising:
(a) providing a biomass-derived liquid hydrolysate stream comprising a fermentation inhibitor;
(b) introducing said liquid hydrolysate stream to a stripping column;
(c) introducing a steam-rich vapor stream to said stripping column to strip at least a portion of said fermentation inhibitor from said liquid hydrolysate stream;
(d) recovering, from said stripping column, a stripped liquid stream and a stripper vapor output stream, wherein said stripped liquid stream has lower fermentation inhibitor concentration than said liquid hydrolysate stream;
(e) introducing said stripper vapor output stream, and a water-rich liquid stream, to an evaporator;
(f) recovering, from said evaporator, an evaporated liquid stream and an evaporator output vapor stream;
(g) compressing said evaporator output vapor stream to generate a compressed vapor stream; and
(h) recycling at least a portion of said compressed vapor stream to said stripping column as said steam-rich vapor stream, or a portion thereof.
12. The process of claim 11 , wherein said fermentation inhibitor is selected from the group consisting of acetic acid, formic acid, formaldehyde, acetaldehyde, lactic acid, furfural, 5-hydroxymethylfurfural, furans, uronic acids, phenolic compounds, sulfur-containing compounds, and combinations or derivatives thereof.
13. The process of claim 12 , wherein said fermentation inhibitor is acetic acid and wherein said stripped liquid stream has less than 10 g/L acetic acid concentration.
14. The process of claim 13 , wherein said stripped liquid stream has less than 5 g/L acetic acid concentration.
15. The process of claim 11 , wherein said water-rich liquid stream contains biomass solids that are concentrated in said evaporator.
16. The process of claim 15 , wherein said biomass solids are derived from the same biomass feedstock as said biomass-derived liquid hydrolysate.
17. The process of claim 11 , wherein said evaporator is a boiler, said water-rich liquid stream comprises boiler feed water, and said evaporated liquid stream comprises boiler condensate.
18. The process of claim 11 , wherein said fermentation inhibitor is recycled to a previous unit operation for generating said biomass-derived liquid hydrolysate stream, to assist with hydrolysis or pretreatment of a biomass feedstock or component thereof.
19. The process of claim 18 , wherein said fermentation inhibitor includes acetic acid.
20. The process of claim 11 , wherein said process is continuous or semi-continuous, and wherein said stripping column is operated countercurrently or cocurrently.
21. A process for separating and recovering a fermentation inhibitor from a biomass-derived hydrolysate, said process comprising:
(a) providing a biomass-derived liquid hydrolysate stream comprising a fermentation inhibitor;
(b) introducing said liquid hydrolysate stream to a stripping column;
(c) introducing a steam-rich vapor stream to said stripping column to strip at least a portion of said fermentation inhibitor from said liquid hydrolysate stream;
(d) recovering, from said stripping column, a stripped liquid stream and a stripper vapor output stream, wherein said stripped liquid stream has lower fermentation inhibitor concentration than said liquid hydrolysate stream;
(e) introducing said stripper vapor output stream, and a water-rich liquid stream, to a rectification column;
(f) recovering, from said rectification column, a rectified liquid stream and a rectification column vapor stream, wherein said rectified liquid stream has higher fermentation inhibitor concentration than said liquid hydrolysate stream; and
(g) recycling at least a portion of said rectification column vapor stream to said stripping column as said steam-rich vapor stream, or a portion thereof.
22. The process of claim 21 , wherein said fermentation inhibitor is selected from the group consisting of acetic acid, formic acid, formaldehyde, acetaldehyde, lactic acid, furfural, 5-hydroxymethylfurfural, furans, uronic acids, phenolic compounds, sulfur-containing compounds, and combinations or derivatives thereof.
23. The process of claim 22 , wherein said fermentation inhibitor is acetic acid.
24. The process of claim 23 , wherein said stripped liquid stream has less than 10 g/L acetic acid concentration.
25. The process of claim 24 , wherein said stripped liquid stream has less than 5 g/L acetic acid concentration.
26. The process of claim 23 , wherein said rectification column vapor stream has less than 0.5 g/L acetic acid concentration.
27. The process of claim 26 , wherein said rectification column vapor stream has less than 0.1 g/L acetic acid concentration.
28. The process of claim 23 , wherein said rectified liquid stream has at least 25 g/L acetic acid concentration.
29. The process of claim 23 , wherein said rectified liquid stream has at least 10 times higher concentration of acetic acid compared to said stripped liquid stream.
30. The process of claim 23 , said process further comprising recovering said acetic acid contained in said rectified liquid stream using liquid-vapor extraction or liquid-liquid extraction.
31. The process of claim 21 , wherein said water-rich liquid stream includes evaporator condensate.
32. The process of claim 31 , wherein said evaporator condensate is derived from an evaporator in which biomass solids are concentrated.
33. The process of claim 32 , wherein said biomass solids are derived from the same biomass feedstock as said biomass-derived liquid hydrolysate.
34. The process of claim 21 , wherein said fermentation inhibitor is recycled to a previous unit operation for generating said biomass-derived liquid hydrolysate stream, to assist with hydrolysis or pretreatment of a biomass feedstock or component thereof.
35. The process of claim 34 , wherein said fermentation inhibitor includes acetic acid.
36. The process of claim 21 , wherein said process is continuous or semi-continuous, and wherein said stripping column is operated countercurrently or cocurrently.
37. The process of claim 21 , wherein step (g) comprises compressing and/or conveying said rectification column vapor stream using a device selected from the group consisting of a mechanical centrifugal vapor compressor, a mechanical axial vapor compressor, a thermocompressor, an ejector, a diffusion pump, a turbomolecular pump, and combinations thereof.
38. The process of claim 21 , wherein said water-rich liquid stream includes one or more additives capable of reacting with said fermentation inhibitor.
39. The process of claim 38 , wherein said fermentation inhibitor includes acetic acid, and wherein said one or more additives include a base; said process further comprising generating an acetate salt in said rectification column.
40. The process of claim 39 , said process further comprising recovering said acetate salt contained in said rectified liquid stream using liquid-vapor extraction or liquid-liquid extraction.