Equipment ans Systems for Corn Wet Milling

1. Equipment and Systems
for Corn Wet Milling

2. Corn Wet Milling Process Flowsheet
2

3. 3
Dewatering, Germ Washing,
and Fiber Washing
Dewatering and Germ Washing
Economical corn wet milling practice
requires dewatering of the supply
stream ahead of the degerminating
mills. Also the separated germ must
be washed to get a high purity germ
product free of starch.
Gravity-Fed DSM®
Screens
Dewatering and germ washing are
done more effectively with Dorr-Oliver
DSM screens. The DSM screens for
these applications are gravity fed over
a weir. A single stage screen is used
for dewatering. For germ washing,
however, three stages of DSM screens
are used. The wash water flows
countercurrently and removes the
starch quite efficiently as the germ
moves forward from stage to stage.
Benefits of Gravity-Fed
DSM Screens
• No maintenance necessary as
screen media is rugged stainless
steel and there are no moving parts.
• Space needed is minimal since
units are compact and handle
high throughputs. Cascade
mounting arrangement of three
screens also makes effective use
of available space.
• Operation is trouble free due to
non-blinding, wedge wire screen
surface.
• No fumes and spillage as screens
are totally enclosed.
Fiber Washing
To get maximum starch recovery,
while keeping any fiber in the final
product to an absolute minimum, it is
necessary to wash the free starch
from the fiber during processing.
Pressure-Fed 120 DSM®
Screens
Most plants accomplish this very
economically today with the Dorr-
Oliver Fiber Washing System. The
system consists of six stages of 120
DSM screens. The pressure fed screens
are arranged for countercurrent
washing of the fiber, with the starch
reporting to the undersize. The
extremely fine separations are possible
only with our highly polished wedge
wire screen surfaces with openings as
fine as 50 microns. The DSM screen’s
precisely selected screen media and its
proven reliability are unmatched by
equipment using fragile textiles or
thin etched screens.
Benefits of Pressure-Fed
120 DSM®
Screens
• Close tolerance, engineered feed
system distributes feed flow
across screen surface with high
velocity for highly effective
separation.
• System’s multi-stage
countercurrent flow design
assures maximum starch yield.
• High capacity compact design
drastically curtails space needed
for fiber washing operations.
• Requires little operator attention
because system is designed for
small sumps, uses standard
pumps and has simple
instrumentation.
• Long service life due to no
moving parts, quick reversible
and totally enclosed design.
• Screens available in single,
double and triple width
configurations for maximum
flexibility in system design.
Gravity-Fed DSM Screen
Pressure-Fed DSM Screen

4. Germ Separation &
Starch Washing Systems
4
Germ Separation
After the corn kernels are steeped for
softening, they are cracked open to
release the germ. The germ contains
the valuable corn oil. The germ is
separated from the heavier density
mixture of starch, hulls and fiber
essentially by “floating” the germ
segments free of the other substances
under closely controlled conditions. This
method serves to eliminate any adverse
effects of traces of corn oil in later
processing steps.
Manifolded DorrClone Systems
To accomplish this critical separation
most efficiently, most plants today use
Dorr-Oliver’s compact manifolded
two-stage Germ Separation System.
Specially sized DorrClone cyclones and
engineered flow distributions are
specifically designed for the magma/
germ separation. Because of the high
centrifugal forces employed, germ is
separated instantly. The first pass makes
a selective separation for optimum
purity and the second pass increases
germ recovery by capturing any germ
that may have been bypassed in the
first stage. This system has given
processors a new standard of process
control and sanitation.
Benefits of Germ
Separation DorrClones
• Maximum germ oil recovery (very
low loss of the valuable process
fraction).
• Easy maintenance and quick
replacement of individual cyclone
units because of the quick opening
couplings.
• Rapid response to process changes
through single instrument control.
• Totally enclosed design assures
clean and fume-free operating
area.
• Lightweight construction and
shipment as a complete factory
assembled package means low
cost installation.
• Modular system design allows easy
expansion when production
demands dictate.
Starch washing
The starch slurry from the primary
separation contains some insoluble
protein and much of the solubles. They
have to be removed before a top
quality starch can be made. Modern
plants are using Dorr-Oliver Starch
Washing Systems for this important
task.
Hydrocyclone Starch
Washing System
A typical Dorr-Clone or Hydrocyclone
Starch Washing System consists of
batteries of 10 mm cyclones in
completely unitized and enclosed
housings, arranged for efficient
countercurrent washing. The centrifugal
forces needed to make the separation
are derived from energy supplied by
pumps. The high rotational velocities in
the individual cyclones cause the starch
to concentrate in the underflow while
the suspended gluten follows the
overflow wash water stream. The
multi-stage systems provide easy and
precise control of the process, resulting
in the uniform, high quality starch
required in today’s highly demanding
marketplace. The latest in starch
washing technology incorporates
recently developed high-efficiency
10mm cyclones for the Starch Washing
System. These high capacity units
incorporate advanced flow channeling
with superior materials and layout to
save money in installed cost and
operating power. Varying plant
capacities can be handled.
Benefits of Starch
Washing Hydrocyclones
• Easy operation because simplified
control system uses self regulation
of intermediate stages.
• Improved sanitation since system is
completely closed and pressurized
• Low maintenance. The only
moving parts are in the standard
centrifugal pumps.
• Capital cost is less because of the
system’s compactness, which saves
on space, and easy expandability
when additional capacity is needed

5. 5
Gluten Dewatering
Gluten Dewatering
Before the gluten moves on to drying
it is good practice to dewater the
gluten slurry from the gluten
thickener, which obviously saves on
the energy required to thermally dry a
high moisture product. This is usually
accomplished economically on a
rotary drum filter with belt discharge.
Dorr-Oliver Eimco
E-Belt Drum Filter
Dorr-Oliver Eimco E-Belt Drum Filters
for corn wet milling applications have
been adapted to meet the industry’s
specific needs for corrosion resistance
and sanitation. Filters are of stainless
steel construction and are equipped
with streamlined internal piping and
valves, snap-in plastic supporting
media and easily adaptable discharge
mechanisms.
Its reliable filtration enhances product
recovery minimizing protein loss.
Benefits of E-Belt Drum Filters
• No more blinding problems and
greatly improved washing and cloth
tracking with the revolutionary
swivel roll concept that doesn’t
require filter cloth rubber edges.
• Delivers high rates of filtration and
high hydraulic capacity for cake
dryness enhancement.
• Hi Hydraulic capacity
• Food design for cleaning and
sanitation
• Innovative cloth alignment design
• Low installation costs and clean
working environment due to
compact design.
• No operator attention required.
• Minimal maintenance

6. Starch Washing and Filtration
6
Pneumapress®
automatic pressure
filters were successfully introduced into
the starch washing and dewatering
process in 1997. Since that time, the
Pneumapress design has evolved to
meet the changing needs of the
industry and Pneumapress equipment
is now installed by the majority of the
major starch producers worldwide. The
starches processed on the Pneuma-
press include corn, wheat, potato and
tapioca starches – including modified,
industrial and food grade varieties.
Pneumapress filters are installed in
starch plants the USA, Germany,
Thailand, Korea, France and Italy.
The design focus of Pneumapress for
the starch industry is to provide a
mechanically simple, sanitary and
efficient filter. Pneumapress filters do
not require rubber seals or dia-
phragms, simplifying the operation
and maintenance of the equipment.
Significant repeat business and
referral sales are indicative of the
success of the Pneumapress design.
The most common throughput sizes
for single filters on native starches are
in the range of 6 to 25 metric tons
per hour dry solids and for modified
starch are in the range of 4 to 20
metric tons per hour dry solids.
The cleaning and hygiene require-
ments at food starch plants are
becoming more stringent. Pneuma-
press has recognized this need and
created a patented sanitary design
option to enable ease of cleaning and
sanitization. This option incorporates
a fully automatic clean in place (CIP)
system.
The Pneumapress filter can be totally
enclosed to prevent product contami-
nation and provide increased safety
for those working in the vicinity. This
enclosure may be designed in 316
stainless steel to provide the ultimate
in sanitary design and safety.
Benefits of Pneumapress Filters
• Very dry filter cakes with highly
effective cake washing when
required
• Highest throughput per unit area
of any filter, which minimizes the
required filter area, equipment
size, number of moving parts and
maintenance downtime
• Advanced filter media design and
effective filter media cleaning
provide very clean filtrate
• Mechanically simple design
eliminates consumables such as
diaphragms and seals
• Filter plates are made completely
from 316 stainless steel
• An isolatable plate design
provides very high equipment
availability
• Sanitary or industrial design with
optional filter housing, structure
cladding, and CIP systems
• Single-sided cake discharge
• Low installation costs
Pneumapress Sanitary Multi-Module Filter
Filter enclosed in sanitary housing
Cake discharge from filter

7. 7
Starch Conversion and
Hydrogenation
Polishing syrup
To remove impurities from syrup in
the sweetener plant, general industry
practice is to use a precoat vacuum
filter, simply because precoat filters
produce the clearest syrups.
Hydrogenation:
Through Catalytic reactions, starch
can be converted into a wide family
of “low calories sugar” used in food
and pharmaceutical products.
Dorr-Oliver Eimco’s
Precoat Filter
features a slow and precise knife
advance system that assures the
lowest precoat expense without
affecting the machine’s high through-
put rates. The precoat material can be
applied to the filter in varying
thicknesses and users get longer
processing cycles between filter
medium replacements. The unit’s
exclusive scraper design enables the
operator to better control removal of
impurities with minimum loss of
precoat material, and this also keeps
operating costs down.
Benefits of Pre-Coat Filters
• Consistently clear and better
quality syrup.
• Longer operating cycles and
equipment life.
• Can be readily adapted to meet
varying process needs.
• Effective use of precoat, without
waste, lowers operating costs.
• Revolutionary precoat discharge
system electronically control for
reduced precoat consumption
and longer filtration cycle.
IBF, Indexing Belt Filter
Dorr-Oliver Eimco IBF is one of the
many products in our portfolio for
vacuum filtration of a wide range of
hydrogenated compounds. The
continuous operation together with a
simple mechanical design reduce
maintenance offering steady and
reliable operation.
Benefits of IBF Filters
• Food design, FDA validated.
• Totally enclosed execution for
solvent washing
• Smooth filtration with no particle
size modification.
• Superior washing efficiency for
maximized product recovery.
• Cleaning in place for complete
sanitation.
Dorr-Oliver Eimco Indexing Belt Filter (IBF)
Dorr-Oliver Eimco Precoat Filter

8. Copyright ©2010 FLSmidth A/S. ALL RIGHTS RESERVED. FLSmidth is a (registered) trademark of FLSmidth A/S. This brochure makes no offers, representations or
warranties (express or implied), and information and data contained in this brochure are for general reference only and may change at any time.
Minerals Processing
Technology Center
FLSmidth Salt Lake City, Inc.
7158 S. FLSmidth Drive
Midvale, UT 84047-5559
Tel: +1 801 871 7000
email: info.slc@flsmidth.com
www.flsmidth.com
Rev08/2010al-us
Suspension @ 60°F Dry Solids Content Water Content
Be Sp Gr % D.S.* Lbs/Gal Lbs/Gal Oz/Gal Gr/Gal Gm/Liter Lbs H2
O Gal Susp Lbs H2
O Lb Starch Gal H2
O Lb Starch
0.0 1.0000 0.00 8.328 0.000 - - - 8.328 - -
0.5 1.0035 0.89 8.357 0.074 1.184 518 8.87 8.283 111.93 13.437
1.0 1.0069 1.78 8.386 0.149 2.384 1043 17.85 8.237 55.28 6.636
1.5 1.0105 2.66 8.416 0.224 3.584 1568 26.84 8.192 36.57 4.390
2.0 1.0140 3.55 8.445 0.300 4.800 2100 35.95 8.145 27.15 3.260
2.5 1.0176 4.44 8.475 0.376 6.016 2632 45.18 8.099 21.54 2.586
3.0 1.0211 5.33 8.504 0.453 7.248 3171 54.28 8.051 17.77 2.133
3.5 1.0248 6.22 8.535 0.531 8.496 3717 63.63 8.004 15.07 1.809
4.0 1.0285 7.11 8.566 0.609 9.744 4263 72.98 7.957 13.07 1.570
4.5 1.0322 8.00 8.596 0.688 11.008 4816 82.32 7.908 11.49 1.379
5.0 1.0358 8.89 8.626 0.767 12.272 5369 91.79 7.859 10.25 1.231
5.5 1.0396 9.77 8.658 0.846 13.536 5922 101.38 7.812 9.23 1.108
6.0 1.0433 10.66 8.689 0.926 14.816 6482 110.96 7.763 8.38 1.006
6.5 1.0470 11.55 8.720 1.007 16.112 7049 120.67 7.713 7.66 0.920
7.0 1.0508 12.44 8.751 1.089 17.424 7623 130.49 7.662 7.04 0.845
7.5 1.0547 13.33 8.784 1.171 18.736 8197 140.32 7.613 6.50 0.780
8.0 1.0585 14.22 8.815 1.253 20.048 8771 150.15 7.562 6.04 0.725
8.5 1.0624 15.10 8.848 1.336 21.376 9352 160.09 7.511 5.62 0.675
9.0 1.0663 15.99 8.880 1.420 22.720 9940 170.16 7.460 5.25 0.630
9.5 1.0703 16.88 8.914 1.505 24.080 10535 180.34 7.409 4.92 0.591
10.0 1.0742 17.77 8.946 1.590 25.440 11130 190.53 7.356 4.63 0.556
10.5 1.0782 18.66 8.979 1.676 26.816 11732 200.71 7.303 4.36 0.523
11.0 1.0822 19.55 9.013 1.762 28.192 12334 211.14 7.251 4.12 0.495
11.5 1.0862 20.44 9.047 1.849 29.584 12943 221.56 7.198 3.89 0.467
12.0 1.0903 21.32 9.080 1.936 30.976 13552 231.99 7.144 3.69 0.443
12.5 1.0944 22.21 9.114 2.024 32.384 14168 242.65 7.090 3.50 0.420
13.0 1.0986 23.10 9.149 2.113 33.808 14791 253.32 7.036 3.33 0.400
13.5 1.1028 23.99 9.185 2.203 35.248 15421 263.98 6.982 3.17 0.381
14.0 1.1071 24.88 9.220 2.294 36.704 16058 274.89 6.926 3.02 0.363
14.5 1.1114 25.77 9.256 2.385 38.160 16695 285.79 6.871 2.88 0.346
15.0 1.1156 26.66 9.291 2.477 39.632 17339 296.82 6.814 2.75 0.330
15.5 1.1199 27.54 9.327 2.569 41.104 17983 307.84 6.758 2.63 0.316
16.0 1.1242 28.43 9.363 2.662 42.592 18634 318.98 6.701 2.52 0.303
16.5 1.1286 29.32 9.399 2.756 44.096 19292 330.25 6.643 2.41 0.289
17.0 1.1330 30.21 9.436 2.851 45.616 19957 341.63 6.585 2.31 0.277
17.5 1.1375 31.10 9.473 2.946 47.136 20622 353.02 6.527 2.22 0.267
18.0 1.1419 31.99 9.510 3.042 48.672 21294 364.52 6.468 2.13 0.256
18.5 1.1465 32.88 9.548 3.139 50.224 21973 376.14 6.409 2.04 0.245
19.0 1.1500 33.76 9.586 3.236 51.776 22652 387.89 6.350 1.96 0.235
19.5 1.1556 34.65 9.624 3.335 53.360 23345 397.23 6.289 1.89 0.227
20.0 1.1602 35.54 9.662 3.434 54.944 24038 411.49 6.228 1.81 2.170
20.5 1.1649 36.43 9.702 3.534 56.544 24738 423.48 6.168 1.75 0.210
21.0 1.1696 37.32 9.741 3.635 58.160 25445 435.58 6.106 1.68 0.202
21.5 1.1744 38.21 9.781 3.737 59.792 26159 447.80 6.044 1.62 0.194
22.0 1.1791 39.09 9.820 3.839 61.424 26873 460.02 5.981 1.56 0.187
22.5 1.1840 39.98 9.861 3.942 63.072 27594 472.49 5.919 1.50 0.180
23.0 1.1888 40.87 9.901 4.047 64.752 28329 484.95 5.854 1.45 0.174
23.5 1.1937 41.76 9.941 4.151 66.416 29057 497.41 5.790 1.39 0.167
24.0 1.1986 42.65 9.982 4.257 68.112 29799 510.11 5.725 1.34 0.161
24.5 1.2036 43.54 10.024 4.364 69.824 30548 522.93 5.660 1.30 0.156
25.0 1.2086 44.43 10.065 4.472 71.552 31304 535.76 5.593 1.25 0.150
BaumeConversionTablesforStarchSuspensions-60°F
*% D.S. = Be deg x 1.7770
Specific Gravity of Starch 1.5 - 1.6
Temperature Corrections
Temperature Add (°Be)
67 .1
73 .2
79 .3
85 .4
91 .5
97 .6
103 .7
113 .9
118 1.0
123 1.1
These tables are based on the work of J.E. Cleland, E.E.
Fauser and W.R. Fetzer.
See Industrial and Engineering Chemistry, Analytical
Edition, Vol. 15, pp 193-200, 1943
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