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AssigneeZenon Environmental Inc.
InventorsJohn M. A. Bento, Hubert L. Fleming
Estimating the term…
"Thin stillage", discharged from a centrifuge in which relatively large >10 .mu.m insoluble solids in an ethanol stillbottoms stream are separated from "whole stillage", is separated in a step-wise membrane separation process to recover lactic acid and glycerol, together. In each step, the permeate recovery is at least 50%. In a first step, an ultrafiltration (UF) membrane means produces a UF permeate stream in which not only essentially all the insoluble portion of said thin stillage >0.0.05 .mu.m is removed as UF concentrate, but also at least 50% of solubles having a molecular weight >2.times.10.sup.5 Daltons, including dissolved proteins in said thin stillage. In a second step to which the UF permeate is fed, a nanofiltration (NF) membrane produces a NF permeate with a rejection of less than 30% of both the lactic acid and the glycerol, preferably less than 25%. Essentially all molecules larger than lactic acid or glycerol are removed in the NF concentrate. In a third step, to which the NF permeate is fed, a reverse osmosis (RO) membrane means produces demineralized RO water which contains essentially no lactic acid and glycerol, because these are rejected in the RO concentrate. Use of the membrane separation process in the production of ethanol based on the dry-milling of corn, eliminates the use of a conventional evaporator.
A two-step membrane recovery process for recovering lactic acid and glycerol, together, from thin stillage obtained from the distillation of beer produced in a fermentation zone, said process comprising,
In a process for the production of industrial ethanol by dry-milling corn, fermenting a saccharified corn meal in a fermentation zone to produce a beer, distilling said beer to produce said ethanol and whole stillage, and centrifuging said whole stillage to obtain a separation of wet cake and thin stillage containing lactic acid and glycerol, the improvement comprising,
A proteinaceous animal feed obtained from corn thin stillage having a pH in the range from 3 to 5 and containing from 5 to 15% total solids, said thin stillage in turn being obtained from whole stillage after fermentation of beer, said feed being essentially free from lactic acid and glycerol, other organic components of said thin stillage being maintained in said feed having a moisture content of less than 5%, said feed consisting essentially of (i) water-insoluble solids having a primary particle size in the range from >0.005 .mu.m to <0.1 .mu.m, (ii) proteins having a molecular weight >1000 Daltons, and (iii) fatty acids having a molecular weight >150 Daltons, wherein each said (i), (ii) and (iii) is present in said corn thin stillage.
In a system for producing ethanol from corn, said system including, milling means for milling corn, liquefaction means for liquefying corn meal, saccharification means for saccharifying liquefied corn meal, fermentation means for fermenting saccharified corn meal, distillation means for distilling beer, and centrifuge means for centrifuging stillbottoms to provide corn thin stillage, the improvement comprising, plural membrane separation means, including, ultrafiltration (UF) membrane means in flow communication with said centrifuge means so as to receive thin stillage under sufficient pressure to produce a UF concentrate and a UF permeate, said UF membrane means including at least one tubular UF membrane having a pore size sufficient to remove molecules in the range from 1000-200,000 Daltons;
A proteinaceous animal feed obtained from corn thin stillage having a pH in the range from 3 to 5 and containing from 5 to 15% total solids, said thin stillage in turn being obtained from whole stillage after fermentation of beer, said feed being produced in a process for the production of industrial ethanol by dry-milling corn, comprising,
Dependencies are inferred from the claim text.