Conversion of biomass into ethanol
A process and system for the conversion of biomass, such as spent brewers grain, into ethanol and other commercial products, such as pelletized fuel, biogas, fertilizer, and livestock feed, is disclosed. The method may include biomass pretreatment, hydrolysis, fermentation, distillation, and dehydration phases.
1. A process for converting a grain fermentation residual product into ethanol, comprising:
A) pretreating a grain fermentation residual product with acid and heat to degrade hemicellulosic material within the grain fermentation residual product, wherein pretreating the grain fermentation residual product includes an in-line processing system, comprising:
A1) treating the grain fermentation residual product with acid to form an acidified grain material;
A2) steam-heating the acidified grain material in a pressurized pipe, to a temperature of between about 325° F. to about 375° F. and a pressure of between about 80 to about 170 psig;
A3) flowing the heated and acidified grain material through a throttle valve into a reaction vessel slightly above atmospheric pressure;
A4) neutralizing the grain material in the reaction vessel;
A5) adding a liquid brewery feedstock or water to provide a mixed material stream; and
A6) cooling the mixed material stream to a temperature of between about 130° F. to about 150° F. with an in-line pipe heat exchanger;
B) hydrolyzing the pretreated grain fermentation residual product with an enzyme to convert starch and cellulosic material to simple sugars;
C) fermenting the simple sugars into ethanol with an ethanol-producing microbe;
D) distilling the ethanol;
E) dehydrating the ethanol to remove water; and
F) recovering whole stillage as an animal or fish feed product.
2. A process for converting a grain fermentation residual product into ethanol, comprising:
A) pretreating a grain fermentation residual product with acid and heat to degrade hemicellulosic material within the grain fermentation residual product;
B) hydrolyzing the pretreated grain fermentation residual product with an enzyme to convert starch and cellulosic material to simple sugars;
C) fermenting the simple sugars into ethanol with an ethanol-producing microbe;
D) distilling the ethanol, wherein distilling the ethanol comprises:
D1) distilling the ethanol with a single distillation column to provide an ethanol/water mixture of between about 35% to about 60% w/w ethanol;
E) dehydrating the ethanol to remove water, wherein dehydrating the ethanol comprises:
E1) flowing the ethanol/water mixture from the single distillation column through a series of three pervaporative membranes to remove water from the ethanol; and
F) recovering whole stillage as an animal or fish feed product.
3. A process for converting a grain fermentation residual product into ethanol, comprising:
A) pretreating a grain fermentation residual product with acid and heat to degrade hemicellulosic material within the grain fermentation residual product;
B) hydrolyzing the pretreated grain fermentation residual product with an enzyme to convert starch and cellulosic material to simple sugars;
C) fermenting the simple sugars into ethanol with an ethanol-producing microbe;
D) distilling the ethanol, wherein distilling the ethanol comprises:
D1) distilling the ethanol with a single distillation column to provide an ethanol/water mixture of between about 35% to about 60% w/w ethanol;
E) dehydrating the ethanol to remove water, wherein dehydrating the ethanol comprises:
E1) treating the ethanol/water mixture with molecular sieves to remove water from the ethanol; and
F) recovering whole stillage as an animal or fish feed product.
4. The process of claim 1 , further comprising:
denaturing the dehydrated ethanol for the production of fuel ethanol.
5. The process of claim 1 , wherein the grain fermentation residual product comprises at least one of the group consisting of spent brewers grain and residual distillers grain products.
6. The process of claim 2 , further comprising:
denaturing the dehydrated ethanol for the production of fuel ethanol.
7. The process of claim 2 , wherein the grain fermentation residual product comprises at least one of the group consisting of spent brewers grain and residual distillers grain products.
8. The process of claim 3 , further comprising:
denaturing the dehydrated ethanol for the production of fuel ethanol.
9. The process of claim 3 , wherein the grain fermentation residual product comprises at least one of the group consisting of spent brewers grain and residual distillers grain products.