System for fermentation of biomass for the production of ethanol
View Patent ↗A biorefinery and a system for producing a fermentation product from biomass are disclosed. The biorefinery comprises a preparation system to prepare the biomass into prepared biomass; a pre-treatment system to pre-treat the prepared biomass with a dilute acid for separation into a first component from which pentose can accessed for fermentation and a second component from which hexose can be made available for fermentation; a first treatment system to treat the first component into a treated first component by removing removed components from the first component; a first fermentation system to produce a first fermentation product from the pentose; a distillation system to recover ethanol from the first fermentation product; and a treatment system to process removed components. The biomass comprises lignocellulosic material, which comprises at least one of corn cobs, corn plant husks, corn plant leaves and corn plant stalks.
1. A method for producing a fermentation product in a fermentation system from a biomass comprising the steps of:
(i) pre-treating the biomass with an aqueous composition comprising an effective concentration of acid for reducing formation of inhibitors at a temperature of about 130° C. to about 170° C. for a period of time sufficient to produce a solids component and an aqueous component, which aqueous component comprises xylose and acetic acid;
(ii) supplying the aqueous component to the fermentation system;
(iii) providing yeast to the fermentation system in a concentration in the range from 5 to less than 150 grams of yeast on a dry basis per liter of the aqueous component, wherein the yeast can ferment the xylose into the fermentation product;
(iv) maintaining the aqueous component and yeast in the fermentation system at a temperature of between about 26° C. and about 37° C. and at a pH of between about 4.5 and about 6.0 for a time of no less than 18 hours; and
(v) recovering the fermentation product from the fermentation system;
wherein the biomass comprises lignocellulosic material.
2. The method of claim 1 , wherein the lignocellulosic material consists essentially of corn cobs, corn plant husks, corn plant leaves and corn stalks.
3. The method of claim 1 , wherein the aqueous component comprises xylose at about 2 to 5 percent by weight.
4. The method of claim 1 , wherein the aqueous component further comprises glucose and the yeast is capable of fermenting both the xylose and glucose into ethanol.
5. The method of claim 1 , wherein the yeast comprises Saccharomyces cerevisiae.
6. The method of claim 1 , wherein the fermentation product comprises at least 1.5 percent ethanol by volume.
7. The method of claim 1 , wherein the fermentation product comprises at least 2.0 percent ethanol by volume.
8. The method of claim 1 , wherein the fermentation product comprises ethanol and wherein at least 75 percent of the xylose has been converted into ethanol by fermentation.
9. The method of claim 1 , further comprising the step of treating the aqueous component to increase the concentration of xylose.
10. The method of claim 1 , wherein the lignocellulosic-material comprises cellulose and lignin.
11. The method of claim 1 , wherein the step of maintaining the aqueous component and yeast in the fermentation system is for a time of no less than 24 hours.
12. The method of claim 1 , wherein the lignocellulosic material comprises at least one of corn cobs, corn plant husks, corn plant leaves and corn plant stalks.
13. The method of claim 1 , further comprising the step of
(vii) supplying the solids component to the fermentation system;
wherein the solids component comprises hexose.
14. The method of claim 1 , wherein the acid concentration is between about 0.8 and 1.1 percent by weight.
15. The method of claim 1 , wherein the acid concentration is between about 0.05 and 0.5 percent by weight.
16. The method of claim 1 , wherein the acetic acid is present in the aqueous component in an amount in the range from 3,000 to 6,400 parts per million.