Note: Descriptions are shown in the official language in which they were submitted.
~ 292-190
Background of the Invention
Materials which contain starch and protein, o:Eten accompanied by other
so:Luble and insoluble substcmces, are comlllercia:lly processed to separate these
materials into var:i.ous :Lractions, W]liC}l Illay also be :Eurther processed, if de-
sired. The weight of each fraction, its composition and the total percentage
of material recovered depends both upon the composition of the raw material and
on the exact processing steps to which it is subjected.
In commercial processing, it is desire~l -to maximize the tota:L value
o:E all the fractions recovered, as long ~s the increased value is greater than
any increased costs ol processing. In general, the value of a Eraction is
greater as its purity is increased, alld the total value is greater with in-
creased recovery of the more valuable :Eractions.
The art to which this invention relates has been very active through
the years, as evidenced by the following patents:
U.S. Patent No. 2,6~8,826 refers to a process wherein a starchy mate-
rial is transformed into a magma containing solubles and unconverted starch
which is centrifuged to provide an overflow containing the solubles and an
underflow containing the starch. A fresh water wash is introduced into the
centrifuge zone.
In U.S. Patent No. 3,236,7~0 there is disclosed a process for produc-
i.ng alcohol which entails degerminating corn to form a germ fraction and a
degerminated starchy fraction; extracting the germ fraction for its germ oil;
adding some of the extract to the degerminated fraction; cooking the combined
fractions; neutralizing the cooked material, cooling the cooked mash to saccha-
rifying temperature; saccharifying -the cooled mash cooling to fermenting tempera-
ture; fermenting and recovering the a.lcohol.
U.S. Patent No. 3,236,7~0 discloses a process wherein, instead of mill-
U.S.S.N. 170,033 - 1
ing the fiber after gert,l removal and separation of the "grit starch", the fiber
and its associatccl starcll and protein are put through an alcohol-making proce-
dure. In this process, yeast is not recycled ancl starch is lost to fermcllta-
tion with the mol ancl gluten comillg from the primclry separator.
U.S. Patents 2~230,31c and 2,063,223 describe the re-use of yeast to
increase alcohol yields but only in reference to molasses, which is clarified
before fermentation.
Distilleries typically produce grain alcohol by converting the starch
in grain to sugar, fermenting the sugar to alcohol, recovering the aLcohoL by
dist:illation, and recovering the remaining materials by removing the water.
T]lis residual material is solcl as an:imal feed and has tnUCIl lcss value thall the
alcohol. The total value of production is increased by maximizing the recovery
of starch as alcohol rather than allowing it to go to -the feed fraction which
has lower value. Furthermore, the value of the fec-~d is improved throug~h effec-
tive increase of its protein content when the starch is kept out of it.
Accordingly, it is an object of the present invention to prov:ide a
prc~cess for producing alcohol from corn, starchy roots, legumes and grain which
yields a higher percentage of alcohol than prior ar-t processes.
Another object of the present :invention is to provide a process for
producing by-products with a much higher economic value than prior art processes.
A further object of the present invention is to provicle a process for
producing alcohol which uses less water and energy than prior known processes.
Still another object of the present invention is to produce a new and
valuable product, destarched corn gluten.
Summary
The present invention is concerned with processes for maximizing the
cumulative total value of the products made from starch-bearing mater:ials that
-- 2 --
4~7
contain insoluble proteinaceous material, with or without containing other
insoluble and/or soluble substances, by recovering the starch in higl- yields in
the forlll o:E soluble carbohydr.l-tes or as :Eermenta-t:i.oll prod~cts and by recovering
an unusually high percentage o:E -the insoluble protein present in a highly puri-
ficd form.
Suitable raw materials include starchy rootsJ legumcs, and grains,
but the preferred materials are cereal grains or fractions of cereal g~ains
whicll have been prepared by wet or dry separation methods.
One of the most advantageous uses o:E the processes is i.n the mall~l:Eac-
ture o:E volatile products o:E carbohydrate :Ecrmcntation, espec:ially o:E ethylalcchol (also known as ethanol, alcollol, grain spiri-ts, etc).
-- 3 --
This novel process for producing alcohol from corn, compared wi-th
regular distillery practice:
-produces higher alcohol yields
-produces by-products witll mucll higller value
-uses less fresh water and thus consumes less energy for evaporation
and drying,
and compared with previously used combinations of wet-milling and alcohol pro-
cesses:
-uses less equip3llent
-recovers a substantially grea-ter amount oE starcll cLS alCOI10
-loses less protein to Corn Gluten Feed
-produces a new and valuable product-Des-tarched Corn Gluten.
I`he corn is steeped Eor a length of time in warm water that has been
acidified with S02, at about 50 in -tanks through which the water flows succes-
sively, as is standard practice in the corn wet-milling industry. The process
differs from the standard procedure (where starch is sought as tlle prime pro-
duct) in that steeping is carried out for a shorter period oE time, only long
enough to toughen the hull and germ sufficiently to make clean germ removal pos-
sible in the next step. Because oE the shorter period of steeping7 there is
less solubilization of starch and protein, and therefore, a lower yield of
steepwater solids than otherwise. The carbohydrates and proteins that would
otherwise be solubilized are now available for recovery as alcohol and gluten
respectively. Light steepwater exiting the system is kept preferably high in
solids to reduce the amount of water to evaporate in the Eollowing evaporator.
This is accomplished by reducing the amount of fresh water supplied the whole
system.
-- 4 -
Brief Description of thc Drawings
In the accompallyillg diagramatic drawings forming part hereof similar
elements have been given the same rcEerellce numeral~ in whicll drawings:
Figure 1 is a flow cliagram showing the prior art processes.
Figure 2 is a flow sheet illustrating a preferred embodiment of the
present invention.
Figure 3 is a flow sheet illustrating the prior art dry milling pro-
cess; and
Figure ~ is a flow sheet showing a preferred dry milling embodimellt
according to the instant inventioll.
Detailed Description
In the traditional clistillery operation, dry grain is ground by roller
or hammer mills, cooked with water, treated with malt, acid or enzyme to convert
starch into sugars, followed by fermentation with yeast, distillation oE the
alcohol and recovery oE the unfermented materials by evaporation and drying of
the water remaining after alcohol removal. Part of the sugars are consumed in
growing yeast both in the fermenting step and in a propagation step carried on
outside of the process. This diversion of sugar causes a corresponding reduc-
tion in yield of alcohol. Large amounts of fresh water are used in the cooking
and fermentation steps, with correspondingly large amounts to be evaporated and
dried in recovering the by-product.
The cost of alcohol produced by this method is inherently high because
of low alcohol yields, low value of the single by-productg and lligh steam con-
sumption for evaporating and drying the large amounts of water.
Because of the high costs entailed, the traditional distillery process
has been largely supplanted, in the U.S. at least, wherever Grain Neutral
Spirits for beverage purposes, or industrial alcohol Eor solvent or chemical
-- 5 --
9~
intermediate purposes is required. Inclustrial grades have been mostly made by
the hydration of ethylene, and the Grain Neutral Spirits are llOW made almost
en-tirely in combincltioll witll processes originally clesigned to recover othervaluable products Erom grain.
The most important oE these is the corn wet-milling process which has
been developed over a period of more than one hundred years as a means of ob-
-taining in as pure a state as possible, the starch that is present in the
kernels of corn. (See Figure 1).
Illis process is reasonably standard, but may be practiced with var-ia-
tions in details accorcling to local circ~nstances. In acldition to starch, it
recovers other compollents of the kerllel, such as protein, oil, Eiber, and ash in
the form of more or less refined by-products. The general process may also be
used in -the recovery of starch and by-products from other grains such as wheat,sorxhum (milo), barley, etc.
In thc wet-milling process as usually practiced with corn, ~see
Figure 1), shelled grain is cleaned in stage 10, to remove gross impurities,
tramp metal, small particles and dust. In steeping stage 11, the cleaned
kernels are steeped in water containing soluble ingredients of corn and a ~uan-
tity of sulfur dioxide, for a period of up to ~0 hours or more at a temperature
of approximately 50 C (122 F). The sulfur dioxide water permeates into the
kernel; it toughens the outer hull, toughens the corn germ, which contains most
of the oil~ and softens protein material that holds the germ and hull to the
inner part of the kernel. The inner part oE the kernel consists of a matrix of
protein enclosing granules of starch, and the steeping process also serves to
soften this protein network, to facilitate recovery of the maximum amount of
starch.
During the steeping process, tle water used for soaking is moved
-- 6 --
counter-currently to the corn, and is removed in the form of "l;ght steepwater"
12 which contains protein, ash, carbohydrate, lactic acid, ctc. at a dry sub-
stance concelltratioll of some 3 to 10~. The ligllt steepwater is subsequently
concentrated by an evapora-tor 13 for sale as is, or to be combined in mixer 1
with fiber and other materials and dried 15 Eor use as an ingredient (corn
gluten feed) in animal feed formulas.
After steeping, the kernels are drained oE excess water and are
coarsely milled at L6 to free the -toughened germ from the rest of the kernel.
Because the germ contains a large amount of oil, it is lighter than the other
componellts of the kernel so it Call be separated by gravimetric methods from the
remaining magma by settling in germ separator 17 or by hydroclones, as prac-
ticed by those skilled in the art. Two stages of milling and separation are
usually used; the germ is co~mtercurrently washed free oE adhering materials,
dewatered as indicated at 18, and dried at 19. Valuable corn oil is removed
from it either by expelling or solvent extrac-tion, ~not shown).
The remaining magma 20 consists of Eiber, s-tarch, and protein (gluten);
some of the starch and gluten are freely suspended in the water but a large
amount also remains attached to the cellulosic fiber of the hull. The loose
particles are screened out at 21 and advanced in the process~ while the fiber
is treated to free the adhering protein and starch. This is accomplished by a
fiber mill 22, followed by a series of washing steps and dewatering 23 suspend-
ing the fiber in water, screening it, resuspending it, etc., with the water mov-
ing countercurrently to the fiber. The milled and washed -fiber is -then mixed
in mixer l~ and other materials, and dried at 15 to produce corn gluten feed.
The protein and starch which have been washed -from the fiber join that which
originally passed through the screen 21 and advanced in the process. The nex-t
step is to separate the protein in as pure a form as possible, from this suspen-
sion of starch and protein.
-- 7 --
The starch and gluten are separated using centrifugal machines 24
which produce a protein stream that contains from about 67 to 70% or even a
li-ttle higller dry substance proteill. T}lis material is concentrated, filtered at
25 and dried in dryer 26 and sold as "corn gluten meal". It contains, in addi-
tion to protein and some 15 to 20% of starch a concentration of oils and fatty
materials including "~anthophyll oil" which is valued as a coloring material for
use in chicken feed Eormulations. After the protein has been recovered, there
remains a slurry of starch, with some protein, very fine fiber, and other mate-
rials in solution. The next step is to remove the protein fiber and solubles
whic}l is accomplished by countercurrent washing Wit]l fres]l water in a series of
stages of hydroclones 28, ranging in number rom abo~lt 8 to lS ~ependillg upon
the specific conditions. Tlle impure starch slurry 27 enters the first stage of
the hydroclones and it leaves the last stage in a highly purified condition at
a higll concentration. This washed starch is then dried or used as the raw mate-
rial for treated, converted, or blended starches, for dextrins, or sweeteners
such as glucose, dex-trose, high fructose syrup, etc.
Fresh water enters the last hydroclone stage and leaves the first
carrying with it some starch as well as solubles, protein and fine fiber that
have been washed from the product. The weight of dry material washed back at
this point is often as much as 20 to 25% of the dry substance amount entering
the washing station. It is concentrated in a centrifugal machine 29 and re-
turned to the main stream 30 eitl-er before the fiber washing s-tation or before
the protein separator 24.
The outstanding features of this process are the recovery of high
yields of starch and by-products in purified conditions that add to the value of
each of them. ~urthermore, this is accomplished with -the use of small amounts
of fresh water - in the order of 11 to 12 gallons or less per bushel (5O lbs) of
-- 8 --
~9~497
corn ground, and no water leaves the process except as part of steepwater,
starch slurry or dewatered by-produc-ts, and this is renoved by evaporation or
drying, or leaves as part of -the product or by-product.
ilowever, in order to achieve these results, there are certain penal-
ties that must be yaid: To free the m~i 1m amount of starch during the steeping
operati.on, some protein and carbohydrates are solubilized and become part of
steepwater rather than -the more valuable Gluten ~leal or starch. To recover the
r~-ir-1m starch that is bound to the fiber, considera.ble power :is used i.n milling,
and undesirable amounts of very fine fiber, wh:ich are very difficult to remove,
are formed. The recycle of the starch wash overflow resu:lts in accumlllatiolls o:E
fine fiber, broken starch granules, and protein, which lllake gluten separation
difficult .
It has been found that many of these problems can be overcome by add-
ing a sub-process for alcohol production, whereby starch is recovered as alcohol
from various of the streams. If the fibers are processed for alcohol, a great
deal of power for milling may be saved, and less starch is carr:ied to lower
value Corn Gluten Feed; if part or all of the starch washing recycle mainstream
is processed for alcohol recycle of extra fine fiber and broken starch granules
is interrupted and gluten separation is improved. ~The presence of variable
alcohol capabilities has an added advantage of providing means to smooth out
seasonal variations in demand for starch products). When more alcohol is re-
quired than can be supplied from the starch i.n fiber and starch washing recycle,
other streams, such as the flow 27 from the protein separator 2~ to the sta.rch
washing station 28 can be tapped into as indicated by -the valves 40,~ 2 of
Figure 1.
Alcohol is produced from the starch in these streams in the same man-
ner as if it were whole grain being processed as described above by cooking at
_ 9 _
4~37
31, saccharifying 32, fermenting 33, distillation 34 to remove the alcohol and
recovery at 35 of the unfermented materials. This latter step is different from
whole grain processing in that the solubles content of the solution is very much
lower, so it may be recycled :in toto. I`he insoluble fraction 36 is also less
since it has been reduced by the prior removal of the germ and part of the pro-
tein. After dewatering the insolubles are mixed with concentrated steepwater
from evaporator 13 and dried to produce animal feed material. However, this
feed is higher in protein content than the Corn Gluten Feed of regular corn wet-
milling due to (l) removal of starch which increases the percentage of protein,
and (2) the protein in the starch washillg recycle (and separator underflow when
used) is recovered along with the fibcr. Since the protein content of this
feed material is higller than the normal product, it commancls a higher price in
the market. Alternativelyl a standard protein content can be achieved by adding
lower-cost materials, thus increasing the quantity produced.
Nevertheless, the quantity of more valuable Corn Gluten Meal is re-
duced by virtue of diversion of protein to less valuable feed.
Compared with the Prior Art distillery process, alcohol prod~lced in
this manner is very much less costly, basically due to the higher value of the
up-graded by-products and to the use of much less water for which energy must be
expended in evaporation and drying. The method also benefits from the economies
of scale induced by combining with major starch producing facilities, especially
when the quantity of alcohol is small in relation to the amount of corn pro-
cessed.
However, when it is desired to produce large amounts of alcohol with
relation to the starch produced, or when it is desired to make no starch at all,
certain of the process steps become superfluous, and certain of the process
- 10 -
advantages become diminished. The novel process described below and diagram-
matically shown in l~igure 2 has been designed -to not only overcome these diEfi-
culties but also to produce a new and valuable product.
As showll in Figure 2, the first step of -the process is to soak the
corn for a length of time in warm watcr that has been acidified with sulfur
dioxide at about 50C in tanks through which the water flows successively, as is
standard practice in the corn wet-milllng industry. 'rhe process difers from
the standard procedure ~wllere starch is sought as the prime product) in that
steeping is carried out for a shor-ter period of time, only long enougll to
toughen tlle hull and germ suEEiciently to make clean germ removal i~ossible ;al
the next step~ Because of the shorter period of steeping, there is less solu-
bilization of starch and protein, and thereEore, a lower yield of steepwater
solids than would be normal. The carbohydrates and proteins -that would other-
wise be solubilized are now available Eor recovery as alcohol and gluten respect-
ively. Light steepwater exiting the system is kept preferably high in solids to
reduce ~he amount of water needed to evaporate in the following evaportor.
Tllis is accomplished by balancing the amount of Eresh water supplied the whole
system.
The next step is that of germ removal wllich is carried out according
to any standard corn wet-milling method which recovers germ with little adhered
starch and protein, in a form suitable for expelling or extracting its valuable
corn oil.
The magma remaining after steeping and germ removal is composed of
water, solubles and insoluble material, with water comprising approximately 75
to 80% by weight of the total. The solubles are minerals, proteins~ carbo-
hydrates and other materials, while the insolubles consist primarily of starch,
protein, fiber and fatty mc~terials. Since the presence of high concentrations
- 11 -
of solubles impedes the ability to recycle waters la-ter in -the process, it is
important to reduce them as much as possible at this point, before the starch is
cooked alld solubili~ed.
I`llis is accomplislled by dewater:ing the magma to as lo~ a moisture con-
tent as possible, and Usillg the water to wash germ and especially to supply
water to the steeps whence it exits as l:ight steepwater. This is effective
since solubles follow the water, and if the magma is clewatered from 80~ moisture
to 50% moisture, only one-Eourtll oE the solubles will go forward with lhe de-
watered material. Further reduction can be obtained by resuspending the mate-
rial and dewatering it again. I-t is optional whetller the mclterial is milled
further either before or after dewaterillg.
The ne~t steps of the process are designed to convert all or essenti-
ally all of the starch to fermentable sugars, remove all or essentially all the
carbohydrates and protein from the fiber, and to remove the fiber from the
system; then to remove the protein from the system in a highly purified state.
This is accomplished by the successive steps oE (1~ liquefying and saccharifying
the starch, (2) screening out -the fiber and washing it free of adhering mate-
rials by countercurrent washing with wateZ low in solubles, (3) removing the re-
maining insoluble material (primarily protein) by centrifugal or other means,
followed by dewatering (with or without washing) and drying.
The remaining solution consists primarily of sugars which may be
treated further to produce commercial useful sweeteners or they may be used as a
substrate for fermen-tation to other materials of which ethanol is the most inter-
esting for fuel use. The following descriptions enlarge upon the steps outlined
above:
(1) The liquefaction and saccharification of the starch may be car-
ried out by any of the methods normally used in the industry, such as the "acid",
12 -
"acid-enzyme" or '~enzyme" processes. In the acid conversion method, the starch
slurry :is cooked at an elevated temperature in the presence of strong acid,
usually hydroclllor:ic. ~he s-tarch is converted into shorter-chain carbohydrates
havillg a composition rallgillg from a high l)ercelltage o~ dextrin ancl starch-like
compounds to a very high percentage of dextrose ~D-Glucose), depellding upon -the
conditions of treatment.
In the acid-enzyme method, liquefaction and some saccharification are
done with acid, followed by adjustmellt of conditions and saccharification with
glucoamylase enzyme.
In the enzyllle metllod, lkluefacti.on is carried out with alpha-alDylase
and saccharification with glucoamylase or bo-th may be done with mixecl enzymes
SUC}I as those in barley malt or certain flmgal amylases.
(2) After the saccharification step, the carbohydrates may be easily
washed from the fiber, carrying other solubles and finely divided insolubles,
including the protein, with them. This is carried out by counter-current wash-
ing with fresh or other low-soluble water in a bent-screen or other fiber wash-
ing arrangement which is normally used in the starch industry, except that
fewer stages are required to reduce the amount exiting with the fiber to a very
low level.
After washing, the fiber is dewatered and may be dried separately or
in combination with concentrated steepwater to produce Corn Gluten Feed, an item
of commerce that is used as an ingredient in animal feeds. Other materials such
as corn screenings, refinery residue, etc. may also be added ~o this feed as is
normal practice in the industry. Water removed in the dewatering opera-tion is
passed to the fiber washing station and, by moving counter-currently, helps re-
turn the soluble carbohydrates to the main stream.
(3) The liquid remaining after removal of the washed fiber is a solu-
- 13 -
37
tion consisting of fermentable sugars and small amounts of other solubles such
as inorganic salts and protein. Suspended in this are insoluble substances
such as protei.n (primar:ily) with small amounts o.E finely divided fiber, and
oils and fats.
These insoluble substances are removed by centrifugal methods which
are common in the art, single stage or multiple, or by filtration alone or in
combinatioll with centri:Eugatioil, with or without counter-current washing. They
are dried to about 10% moisture. Comi)ared with the gl.uten produced by normcll
corn wet-milling, this product is very llighly pur;.:Eied and contains up to ~0%
or more pure protein on a dry substance bas:is, as compared w;.th llorlllcll 67 to
75%. It contains a concentration o the xanthophyll oi.l from corn, which is
the coloring material that is used to bring yellow color to poultry skin and
eggs via their feeds. This oil may be recovered by solvent extraction with
hexane or other appropriate non-toxic solvent. Because of its extremely hi.gh
protein content, the gluten has exceptional value as animal or human food and
as a starting point for further processing.
~ 4) After removal of the insolubles, the solution consists essenti-
ally of sugars, which can be processed in different ways. The sugars can be con-
centrated by evaporation to form syrup with or without refining; cast as solid
sugar or crystallized as dextrose, or they can be reacted chemically or especi-
ally fermented to various compounds, of which ethanol is of major importance.
To produce alcohol, the sugar solution is cooled to a suitable tempera-
ture for yeast fermentation in either batch or continuous processing. After
fermentation is complete, yeast - both that which was introduced and that which
grew during the course of the fermentation-is essenti.ally the only insoluble
material present. I-t can then be removed centrifugally, as is often done in
molasses fermentations, but not previously practiced with grain, and reused in a
1~ -
ermentation vat. This recycle allows use of greater amounts of yeast result-
ing in faster .Eermentation. This recycling also obviates the need for growing
more yeast from -the sugars, thereby cnsur:ing a higher yiel.d o:E ~lcohol to the
extent thclt the yeast multiplles due to partially aerobic conditions in the
fermentation, there is excess yeast to be removed in the form of dead and
damaged cells as well as good ones. Since these cells consist of high amounts
of protein, they are useful as an additive to feed materi.als.
~ l example of the practice of the invention is given in the flow
sheet of Figure 2. A charge consis-ting of 1183 pounds ~1000 pounds of dry sub-
stances) of clean corn is placed in a series o tanks 4~1 through WhiCIl warm S02water is flowed at 50C for steey:ing or lcach.ing the corn Eor 10 to 30 hours.
The yield of steepwater solids was 65 pounds and the light steepwater exiting
through line 46 was ~Eound to total 813 poullds including 748 lbs. of water, 682
pounds of water were evaporated in multi-e:Efect evaporator 48. The concentrated
steepwater from evaporator 48 was flowed to feed mixer 49 via line 50.
The charge was flowed from tanks 44 via line 52 to germ mill and
separator system 54 which includes a coarse attrition mill and hydrocyclones as
is commonly practiced. The germ in the overflow were sent along line 56 for
washing in washer 58 using recycled water introduced through line 60. Water is
also recycled from dewatering station 62 via line 64 and from germ dewatering
station 66 via line 68. The germ is dewatered i.n the presses of station 66 and
sent on to germ dryer 70 by way of line 72. After drying, the recovered germ
was found to be 79 pounds including 2% moisture and approximately 39 pounds of
oil.
The underflow from separator system 54 containing fibers, starch, pro-
tein, soluble and insoluble materials is flowed to station 62 via line 55 where
the water content thereof is dewatered from about 80 to about 50%. Optionally,
- 15 -
~9~
the material is milled before dewatering. The expelled water is recycled to
wasll the germ .~nd for steeping via line 64.
In this exalllple~ the en~yme metllod of liqueEaction and sacchariEica-
tion was used. The dewatered material is flowed through the cooking and
liquefying section 74 where the pll is adjusted, alpha-amylase such as J`ermamil
60 of Novo Industri A/S is added, with the addition of 313 lbs of water intro-
duced by line 75 which recycles water from the bottom of the beer stil].
Some 360 pounds oE direct steam are injected during the cooking pro-
cess, and 300 pounds are flashecl ofE after cooking, during cooling to sacchari-
fication temperature of about 60C, the pl-l :is adjusted to 4.0 to 4.5 ancl enough
glucoamylase is added to reach a dextrose equivalent of about 75 in about 6
hours~ Using an en7yme such as Novo 150 produced by Novo Industri A/S the
quantity is approximately 1 to 1.5 liters per metric ton oE dry substance starch.
After saccharification of the starch, the stream passes through line
82 to screening section 84 for removal of coarse insoluble materials, almost
entirely fiber. This is accomplished in a few stages of bent screens such as
normally used in the industry.
The fiber is removed by a fine screen, and is then successively resus-
pended in counter-currently flowing water from tank 83 and rescreened to remove
a ~xi ~m of the soluble material, in section 84. 1033 pounds of fresh water
are introduced here via line 85 and is part of the co~mter-current washing
stream. The solubles removed from the fiber pass through line 81 to the first
screen in 84 and through it to the next station. Washed fiber passes through
line 88 to a dewatering press 90 of usual type, where the moisture content is
reduced mechanically from about 95% to 63%. Water removed here (1401 lbs.) re-
turns to the washing station through line 92 while the dewatered fiber passes
through line 94 to a pre-dryer 96 where the moisture content is reduced to
- 16 -
approximately 20 -to 40%. Predried iber then passes through line 98 to feed
mixer 49 where it is mixed with concentrated s~eepwater as well as other mate-
rials which may optionally be added here S~lCh as corn cleanings, refinery
res:idue, etc. Tlle mixture thcn passes througll line 108 to Feed Dryer 110 where
it is clried in normal fashion to approximately 10% moisture content with usual
milling, screening and recycle.
The sugar solution, wllicll still contains finely divided, suspended
particles of insoluble protein, is sent on by line 112 to one or more centri-
fuges and/or filters 114 for removal of the pro-teln (gluten). Pr.ior to and dur-
i.ng the process of protein recovery some 2~22 pounds of water recycled from thebottom of the beer stlll 80 are added to the stream as a means of washlJIg the
proteln and to dllu-te the sugars to the concentratlon required ln the fermenta-tlon step. The 65 pounds of recovered proteln ls then dewatered ln a fllter 116
from approxlmately 88% molsture to about 60% moisture. T}le water removed at
thls step whlch contains sugars, ls flowed in llne 118 and passes through llne
118 to joln the sugar solutlon comlng from fllters 114 through llne 120. The
dewatered gluten is then flowed through pipe 121 and dried in a usual manner to
about 10% moisture ln dryer 122.
The sugar solut:ion is then cooled -to fermentatlon temperature of about
30C and recycled yeast ls added through llne 124. The amount of water here ls
adjusted to control the concentratlon of alcohol ln the fermented mash as re-
quired by the amount and type of yeast employed, fermentatlon time available,
and other pertlnent varlables. In the example an alcohol concentratlon of 8.1%
by welght (about 10% by volume) was obtained.
I~ermentatlon ls carrled out ln statlon 126, which may be any sort of
batch, semi-contlnuous or contlnuous yrocess. During fermentation, some 398
pounds of carbon dioxide gas are evolved ancl this may be recovered or not accord-
lng to the economlcs of the case.
- 17 -
9~
After fermentation has been concluded, the mash passes through a
normal type of noææle centrifuge 129 for recovery of the yeast. ~lost of this
:is returlled tllrougll line l24 to the fermenter station, but some is bled of~ and
incorporated into tile Corn Gluten l:eed. The fermellted mash, W]liC]I iS now
essentially free of :insolubles passes -througll line 130 to the f:irst distillation
stage 80 (often called "beer still") where the alcohol is stripped from the mashthrougll line 132. In the example, 384 pounds of crude alcohol were recovered
for further processing, at a concelltration of about 74% by weight. This concen-tration may be varied according to usual practice, and the alcohol Cclll be
further processed as re(luired to produce spirits for beverage ind-lstrial, fuel,
or other uses.
The water discharged from the bottom of the beer still 80 columll con-
tains very low solubles and is recycled through line 13~ for re-use at earlier
points in the process as descr:ibed above.
Table I below provides a comparison between yields obtained with the
present process and the prior art distillery process. In that table, it is
noteworthy to remark that the present process uses only 682 pounds of fresh
water against 3212 pounds by the prior art process. It also used 360 pounds o
steam against 547 pounds by the prior art process. The amount of alcohol pro-
duced by the present process is 3~4 pounds against 369 pounds yielded by the
other distillery process. Advantageously, the subject process produces corn oil
and gluten not produced by the other.
- 18 -
~L~g~ 7
Lbs/1000 lbs Clean Corn D.S.(Dry Sollds)
ProductionDi~tilleryPresent New Proce~s
Alcohol (Absolute
Ba~ls3 369 3~4
Feed Product
30% Pro~ein 362
21~/o Protein - 232
Corn Oil - 34
Gluten (80% Proteln~ - 72
Fresh Water Consumed
by Process 3413 1033
Steam for Cook~ng 547 360
Water to b~ evaporated
in Dryers ~88 362
~n evaporater~ 3212 682
The above example has been given as only one presently
preferred embodiment of the invention. Many variations
w~thin its spirit will occur to those skilled in the art ancl
these variations also form part of this invention.
For example, the advantage~ of this process may be
combined with the ~tarch alcohol process earlier descrlbed
in Figure I.
It may also advantageously be combined with the classical
distillery proces~ where gra~n i~ dry-milled. The proces~
may be shortened to remove both germ and fiber to~ether.
The raw material u~ed may be any carbohydrate bear~n~
materials sueh as graln sorghum (milo~, wheat, barley,
rice, ~oybean, alfalfa, tapioca, potato, yams and banana~.
J.9
.. ~ _
~ ~9~ ~ 7
! The sugar~ may be fermented to materials other than
alcohol, such as N-butanol and aeetone, glycerol, lactlc acid,
butylene glycol, citrlc, gluconic an~l itaconic aclds and
Iderivat:ized compounds thereof by reaction~ known per ~e.
l'he sugar~ m~y be removed without fermentatîon a~ a
concent:rated ~yrup, a~ CA~t or cry~tallized sugars.
The proce~s may be practiced without recycle of the
yea~, where its production is glven preference over yields of
alcohol,
The variou~ non-carbohydra~e ~treams may be co~binl!d
in dlf~erent ways with or without addi~ion o other materials
to form different by-products without depar~in~ from the
'spir~t of the invention.
The proce~s may be practiced without full recycle of
:l5 the liquid remaining after the alcohol ha3 been 3tripped o~f,
without affec~in~ the ~cope of the lnvention, but thi~ will
require more fresh water and energy to evaporate the liquid.
An~ther emhodiment of the invention is its use in
improving the traditional distillery process for producing
alcohol where a dry-milled gxain is used. In this process,
the ground grain i5 suspended in water, and the starch con-
verted to sugars by quccessive steps of cooking and ~reatment
with acids and~or enzymes. ~he temperature and acidity are
adjusted and the resulting mash is placed in a fermenter tank
and 'starter' yeast is supplied from an ou~side source.
In the fermenter tank, the yeast consumes ~he fermentable
~g~
~ug2rs and both propagates itself and produces alcohol. When
the sugar ha~ been consumed, the alcohol is removed by
distillation, and the non-fermentable materials are recovered
for use as an animal ~eed product, usually as a single by-
product called "Distillers Drled (;rains and Solubles".
This process may be improvecl in several ways by using
the invention:
tl) Yeast may be recycled and this results in using
shorter fermenta~ion time and smaller fermenters.
~2) ~ore alcohol is formed from the carbohydrate, since
les~ yeast is grown.
( 3) A new ~y-product which contains high purity
protein i8 produced.
Figure 3 outlines the traditional process, and
Figure 4, the application of the novel proce~sO In the
la~ter case, th~ coar~e insolubles (mostly cellulosic
materials), and the fine in~olubles (mostly protein and
fatty materials)are removed before fermentation. ~f~er
fermentation, the yeast which is the only remaining insoluble
material i~ recovered centrifugally and returned to the
~rmentera. Animal feed i8 produced by drying the coarse
insoluble together with the solubles; no decanter i~ r~qui~ed
after ~he stills, ~ince the insolubles have already been
removed in earlier ~tep~0
