Model III Solvent Extractor
Crown Iron Works Company

Model III Solvent Extractor

The Crown Model III Solvent Extractor
designed to meet your production requirements

THE CROWN DESIGNThe Crown Model III Continuous Loop Shallow Bed
Extractor offers the benefits of low power requirements,
excellent component life, ease of operation and thecapability of high operating capacities. The Crown design isthe most efficient of several methods of extracting vegetableoils from oil-bearing seeds. This design maximizes
extraction efficiency while at the same time minimizes
steam consumption.

POINTS TO REMEMBER• More than 1,000 operating years worldwide with acumulative capacity of more than 300,000 TPD.

• Low solvent carry-over reduces both steam and hexane
consumption in the DT.
• Automatic extractor feeding assures 100% filling without
operator control or intervention.
• Continuous, non-mechanized discharge to the spent flake
conveyor for trouble-free operation.
• Surging of DT eliminated resulting in improved overallplant operation.
• Bed turned over in the middle of the extraction processinsuring even extraction top to bottom.

• Proven design since introduction in 1980, backed by acompany established in 1878.

• No closed cells and a minimum of “side wall” effect means
there is no channeling of the solvent along internalvertical surfaces.

• Capacities of up to 8,000 rated tons per day of flaked
soybeans, more when operating with expanders.

• Extractor proportions ideal for maximum percolation ratewith a typical width to depth ratio of 3:1 to 4:1.

• Available in small capacities (pilot size) or for processing
specialty products.

• No tuning, balancing or adjusting of operating
parameters required.

• Design operates on a wide variety of products including
the direct extraction of soybeans and cottonseed, andprepress extraction of rapeseed, peanuts, sunflower, copra
and various other special products.

• Installation can be accomplished without welding or other“hot” work.

FEATURES OF THE CROWN EXTRACTOR• High resale value of a used extractor, due to uniquebolted construction.

• Pre-assembly in workshop ensures that all components fit
together properly in the field.
• Shallow bed design works with all types of materials overa wide range of conditions.
• Self-cleaning V-bar screens maximize drainage without
the need for screen cleaning mechanisms.
• Maximum surface area of any extractor type with aminimum required floor space.
• Expanders not required for efficient operation even whenprocessing delicate or poor draining materials.
• Two methods of increasing capacity; add expanders for
20-25% increased capacity, and extend the extractor for
another 20-25% increase.

• Significantly reduced installation time of a Crown
extractor in a new or existing plant.

• Robust design and slow internal speeds result in longcomponent life.
• Easy and infrequent chain adjustments for reduced
downtime due to extractor maintenance.
• Reduced power requirement of drive due to downflow ofmaterial in tail section.
• Smooth, mechanical operation with all products.
• No “dump tanks” required due to low volumes of miscellapresent in the meal.

SOLVENT EXTRACTION BASICS
Every extraction system must satisfy four fundamental
requirements in order to effectively remove oil in the solvent
extraction process.
• The product must be properly prepared so as to rupture
the oil cells, minimize the distance required for thesolvent to displace the oil, and maximize the percolation
rate of the solvent.
• Adequate solvent must be introduced into the process tokeep the miscella relatively low in oil content. Thispermits the dissolving and displacement of more oil at
each stage of the extraction process.

The Crown
Model III
Extractor

SOLIDS IN
ELECTROEXTRACTOR DRIVE-SPEEDCONTROLLED BY THE
INCOMING VOLUME OF RAW
SOLIDS READ BY THE
ELECTRONIC SENSOR

F• The combination of sufficient residence time of theproduct in the extractor and adequate percolation rate ofmiscella through the product bed must be maintained toobtain maximum extraction efficiency.
• Sufficient number of extraction stages must be present in
the extractor in order to ensure that the miscellaconcentration in the final washing stage is low enough toremove the remaining oil present in the material.
Of the three basic types of extractors used in the industry
today (shallow bed, medium bed, and deep bed), only; theCrown shallow bed design ensures that all of theserequirements will be satisfied regardless of the material
being processed or the operation of the preparation process.

MODEL III EXTRACTOR OPERATION
Material is fed into the extractor through the inlet hopper
located on the top section of the extractor. The internal
chain assembly carries the material across the length of the
top section. The material is supported by Crown V-bar
screens, which are arranged linearly to ensure that they arecontinuously and automatically cleaned. The material isconstantly washed by several stage pumps during this time.
In the tail section of the extractor, two important functions
are automatically performed. First the material is slowly
turned over ensuring that the bed is inverted when it leaves
the tail section. Second, miscella added to the top section
travels with the material, creating a soaking section which
aids in removal of oil in the bottom section of the extractor.
The downward travel of the material in the tail section
reduces the power requirement of the drive. Large rollers of
the internal chain travel on “guide rails” which ensure that
there is no wear on the fixed plates of the tail section.

EXTRACTED SOLIDSOUTLET

FRESH SOLDRAINAGE SECTION

Crown Iron Works Company

INLET HOPPER WITH
ONIC LEVEL SENSORFIRST WASH

Hydroclone
The Crown Hydroclone removes
the final traces of fines from thefull miscella. The miscella canbe pumped directly to theevaporation system.

HYDROCLONEMISCELLA CLARIFIER

FULL MISCELLA OUTLET
COUNTERCURRENTRECYCLE STAGESOLVENT
RINSE

Bar Screen
FINAL
RECYCLESELF-CLEANINGSTATIONARY VEE-BAR
SCREENSCOUNTERCURRENTRECYCLE STAGESThe flake bed acts as a brush –it continually sweeps thestationary Bar Screen clean offlow-obstructing fines.

In the bottom section, the material is washed by successively
leaner stages of miscella, until the last stage where puresolvent is used to remove the last remaining oil. In thedrainage section the bed is raised up a shallow ramp, which
ensures that no excess solvent can over-flow into thedischarge and be carried on to the DT. In the discharge
section, the extracted material falls by gravity in small
increments into the spent flake conveyor, ensuring a smooth,
continuous and even feed to the DT.

THE PROBLEMS WITH DEEP BED EXTRACTORS

From the fresh solvent wash section, the miscella travels
from stage to stage, counter-current along the bottom sectionof the extractor. At the end of the bottom section, anautomatic level controller pumps or lifts the miscella to thetop section of the extractor. From here the process isrepeated until the final or full miscella is removed from thelast washing stage on the top section.

With roto cell extractor designs, the deep material bed isoften up to three meters in height. This causes a channelingof solvent through the material bed, leading to inconsistentpercolation and the formation of dry areas throughout thematerial.

The full miscella is pumped through one or morehydroclones mounted on the top section of the extractor.
Here, any fines present in the miscella are removed anddeposited on top of the meal bed. The scrubbed full miscellais then sent to distillation for removal of the solvent.
All process flow rates, including the extractor chain speed,
miscella lift, and full miscella discharge are smoothly andautomatically controlled without the need for operator
intervention. The fresh solvent flow rate can be set to obtainmaximum overall plant operating efficiency.
On smaller and medium sized extractors, the number ofwashing stages is seven or more. On larger extractor sizes(4000 TPD and larger) this number is at least 10 and can beas high as 13 on some models. This high number of extractor
stages results in the maximum extraction efficiency for any
given set of operating conditions.

All deep bed extractors can suffer from poor percolation,
compression of materials, long extraction times, slow
drainage and high solvent carry over.
Deep bed extractors traditionally lack uniformity in material
discharge rates. They may produce materials of varying
solvent content and varying bulk densities. In addition, deep
bed extractors may damage fragile materials.

Slow drainage is a common characteristic in deep bed
extraction and results in a high solvent carry over to the DT,
and greater overall plant steam consumption.

THE ADVANTAGES OF A CROWN SHALLOW BED
EXTRACTOR
With the shallow bed design, solvent is evenly distributedwith consistent percolation throughout the bed of material.
Due to the shallow bed design, material is not compacted
and the percolation rate remains high regardless of thequality of the prepared product.
Since there are no cells or internal vertical dividers,channeling of solvent and dry spot formation are eliminated.
A larger surface area to volume ratio ensures that themaximum washing rate can be used resulting in the highest
attainable capacity for a given size of extractor. This feature
also produces an extractor which is more forgiving when
operating on fine or poorly prepared material.
The main advantage of the Crown shallow bed design overthe deep bed design is the significantly improved drainage ofa Crown extractor. This translates directly into increased oilremoval, reduced steam consumption in the DT, improved
overall plant operation, reduced down time and a netincrease in the profitability of the plant.

NORTH AMERICAN HEADQUARTERS
CROWN IRON WORKS COMPANY
2500 West County Road C
Roseville, MN 55113 USA
Ph: +1-651-639-8900
Fax: +1-651-639-8051
sales@crowniron.com

EUROPEAN HEADQUARTERS
EUROPA CROWN LTD.
Waterside Park, Livingstone Road
Hessle, East Yorkshire, HU13 OEG England
Ph: +44-1482-640-099
Fax: +44-1482-649-194
sales@europacrown.com

OFFICES:ARGENTINA, BRAZIL, CHINA, HONDURAS, INDIA, MEXICO, RUSSIA AND UKRAINE03/07

P.O. Box 1364 Minneapolis, MN 55440-1364 USA
Telephone: 1.651.639.8900 Fax: 1.651.639.8051
www.crowniron.com