System and method for enhanced ethanol production
A system for producing ethanol comprises a rectifier column that receives a first process stream comprising from about 42% to about 60% ethanol, wherein the rectifier column purifies the first process stream to provide an ethanol product stream that is at least about 90% ethanol, and one or more evaporators configured to evaporate water from a second process stream, wherein the one or more evaporators generate vapor, and wherein at least a portion of the vapor supplies heat energy for separation of ethanol from water in the rectifier column.
1 . A system for producing ethanol, the system comprising:
a plurality of at least four columns arranged in fluid communication in series, the plurality of at least four columns comprising:
a beer column;
a first rectifier column that receives a first process stream via the fluid communication from the beer column wherein the first rectifier column purifies the first process stream to provide first ethanol product stream that is a fuel-grade ethanol;
one or more molecular sieves in fluid communication with the first rectifier column to receive a second process stream from the first rectifier column, wherein the one or more molecular sieves are in second fluid communication with the first rectifier column to pass a regens stream back to the first rectifier column from the one or more molecular sieves;
a side stripper that receives a third process stream via the fluid communication with the first rectifier column, and a fourth process stream that includes a vapor; and
a second rectifier column that receives a fifth process stream via the fluid communication from the side stripper, wherein the second rectifier column is in fluid communication with the one or more molecular sieves and receives a sixth process stream from the one or more molecular sieves;
one or more evaporators configured to evaporate water from a seventh process stream, wherein the one or more evaporators generate the vapor;
wherein at least a portion of the vapor supplies heat energy for separation of ethanol from water in the side stripper; and
wherein the second rectifier column purifies the fifth process stream and the sixth process stream to provide a second ethanol product stream that is a high-grade ethanol.
2 . The system of claim 1 , wherein the seventh process stream is formed from at least a portion of a stillage stream, and wherein the one or more evaporators are configured to evaporate water from at least the portion of the stillage stream to generate the vapor.
3 . The system of claim 1 , wherein the second ethanol product stream from the second rectifier column is at least about 94.9% ethanol.
4 . The system of claim 1 , wherein the second ethanol product stream from the second rectifier column has no more than about 200 parts per million methanol, no more than about 10 parts per million acetaldehyde and acetal, and no more than about 300 parts per million of alcohols other than methanol and ethanol.
5 . The system of claim 1 , wherein the second rectifier column comprises a plurality of trays arranged in a stack from a bottom of the second rectifier column to a top of the second rectifier column, wherein the second ethanol product stream is extracted from one or more intermediate trays located between the top and the bottom of the second rectifier column.
6 . The system of claim 1 , wherein the first ethanol product stream has a first ethanol purity, wherein the second rectifier column provides the second ethanol product stream having a second ethanol purity that is different than the first ethanol purity.
7 . The system of claim 6 , wherein the first ethanol product stream is additionally extracted from a first position on the second rectifier column and the second ethanol product stream is extracted from a second position on the second rectifier column.
8 . The system of claim 1 , further comprising:
a condenser that receives the second process stream prior to the one or more molecular sieves; and
a reflux tank that receives a portion of the second process stream to bypass the one or more molecular sieves;
wherein the reflux tank is in third fluid communication with the first rectifier column to return a liquid of the portion of the second process stream back to the first rectifier column.
9 . A system for producing ethanol, the system comprising:
a plurality of at least four columns arranged in fluid communication in series, the plurality of at least four columns comprising:
a beer column;
a first rectifier column that receives a first process stream via the fluid communication from the beer column wherein the first rectifier column purifies the first process stream to provide a first ethanol product stream that is a fuel-grade ethanol;
one or more molecular sieves in fluid communication with the first rectifier column to receive a second process stream from the first rectifier column, wherein the one or more molecular sieves are in second fluid communication with the first rectifier column to pass a regens stream back to the first rectifier column from the one or more molecular sieves;
a side stripper that receives a third process stream via the fluid communication with the first rectifier column; and
a second rectifier column that receives a fourth process stream via the fluid communication from the side stripper, wherein the second rectifier column is in fluid communication with the one or more molecular sieves and receives a fifth process stream from the one or more molecular sieves;
wherein the second rectifier column purifies the fourth process stream and the fifth process stream to provide a second ethanol product stream that is a high-grade ethanol.
10 . The system of claim 9 , further comprising:
one or more evaporators configured to evaporate water from a sixth process stream, wherein the one or more evaporators generate a vapor that is at least part of a seventh process stream, and wherein at least a portion of the vapor supplies heat energy for separation of ethanol from water in the side stripper.
11 . The system of claim 10 , wherein the sixth process stream is formed from at least a portion of a stillage stream, and wherein the one or more evaporators are configured to evaporate water from at least the portion of the stillage stream to generate the vapor.
12 . The system of claim 9 , wherein the second ethanol product stream from the second rectifier column is at least about 94.9% ethanol.
13 . The system of claim 9 , wherein the second ethanol product stream from the second rectifier column has no more than about 200 parts per million methanol, no more than about 10 parts per million acetaldehyde and acetal, and no more than about 300 parts per million of alcohols other than methanol and ethanol.
14 . The system of claim 9 , wherein the second rectifier column comprises a plurality of trays arranged in a stack from a bottom of the second rectifier column to a top of the second rectifier column, wherein the second ethanol product stream is extracted from one or more intermediate trays located between the top and the bottom of the second rectifier column.
15 . The system of claim 9 , wherein the first ethanol product stream has a first ethanol purity, wherein the second rectifier column provides the second ethanol product stream having a second ethanol purity that is different than the first ethanol purity.
16 . The system of claim 15 , wherein the first ethanol product stream is additionally extracted from a first position on the second rectifier column, and the second ethanol product stream is extracted from a second position on the second rectifier column.
17 . The system of claim 9 , further comprising:
a condenser that receives the second process stream prior to the one or more molecular sieves; and
a reflux tank that receives a portion of the second process stream to bypass the one or more molecular sieves;
wherein the reflux tank is in third fluid communication with the first rectifier column to return a liquid of the portion of the second process stream back to the first rectifier column.