Countercurrent Liquid - Solid Extraction - The Kennedy Continuous Pilot Plant

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Countercurrent Liquid-Solid

ExtractionT H E K E N N E D Y C O N T IN U O U S P IL O T P L A N T

FRANK LERMAN, ANGUS B. KENNEDY, AND JEROME LOSHIN

Vrclcan Copper and Supply Company, Cincinnati, Ohio

Numerous pilot plant runs on over 20 dieerent lcinds of

extractable solids have been made to demonstrate the

effectiveness of th e Kennedy extraction system for co n-

tinuous, countercurrent extraction and product recovery.

The continuous pilot plant, of ype 316 stainless steel con-

struction, has proved the versatility, efficiency, and flexi-

bility of the Kennedy extractor, and has indicated the

quality of the products obtainable. The pilot plant has

been an invaluable demonstration unit and also has

given excellent data for use in design of comm ercial units .

iMaterials heretofore considered unsuitab le fbr contin uous

solvent extraction have been readily and thoroughly ex-

tracted. A full program of pilot plant work has been

scheduled for the coming months, involving several new

extractable materials.

ARLY in th e development work on the Kennedy extrac-E ion system a t the Vulcan Copper and Supply Company,

the need was recognized for a continuous pilot plant that could

duplicate closely commercial solvent extraction and recovery

operations. Previous pilot plant and commercial installations

built by Angus B. Kennedy, inventor of the extractor, already

had indicated t he versatili ty an d flexibility of th e Kennedy ex-

tractor.

The first installation of this ty pe was built in 1927 in Charlottes-

ville,Va., for the extraction of natural dyes and tanning extracts

from bark and wood. Thi s machine was of rath er crude

construction, but clearly demonstrated a considerable saving

over t he leach tubs a nd autoclave methods of extraction in gen-

eral use.I n later years, th e extractor was redesigned for the solvent ex-

traction of vegetable oils, and a number of patentable improve-

ments were incorporated at th at time; these greatly increased the

efficiency of the app ara tus . In 1941, a small brass extractor of

this improved design was installed at the WoIf Company’s plan t,

Chambersburg, Pa. The capacity of this small pilot extractor

was approximately 1 cubic foot of solids per hour for a through-

put time of 1hour.

It s prime purpose was t o furnish design da ta for the large com-

mercial plant, which was subsequently installed a t Hershey, Pa.,

for the extraction of cocoa but ter fro m cocoa residues. Thi s

extractor was used also to solvent ext ract various vegetable oil-

bearing materials, such as tung kernels ( I ) , soybeans, and flax-

seed, and t o ra rrv out certain special liquid-solid contacting op-

erations, such as the water washing of cellulose ace tat e and t

recovery of zein from corn proteins.

The commercial solvent extraction plant for the recovery

cocoa butter from flaked cocoa beans, expeller cake, filter cak

hulls, a nd foots has been in operation for 6 years at the so

plant of the Hershey Estates, Hershey, Pa It has a capacity

50 tons per da y of expeller cake.

A small brass extractor was installed a t the Easte rn Regio

Research Laboratory of the U. S. Department of Agriculture

Philadelphia, Pa., to extract vitamins from various vegetab

materials. Its capacity is approximately 1 cubic foot per hour

solids for 1 hour’s throughput contacting time. Recently, a pi

plant of steel construction, with an ext ractor of ab out four tin

th e capacity of th e previous pilot units, was built an d operat

at t he Northern Regional Research Laboratory of t he U.Depart ment of Agriculture at Pcoria, Ill., for tho extraction

soybeans with alcohol.

A large srale Kennedy extractor mas built and installed on t

West Coast for the acid M ashing and water neutralization of p

tin for peal: war requiremonts. Cypress wood was used as t

sub sti tut e construction material; it resisted the acid corrosion

the emergency period.

It was to extend and confirm these previousextractions, to t

extractions of numerous other materials using various solven

and to ob tai n basic operating dat a for the design of commerc

installations for processing specific materials that the prese

continuous extraction and recovery pilot plant has been bu

on the grounds of the Vulcan Copper and Supply Company

Cinrinnati.

DESCRIPTION OF THE KENNEDY PILOT PLANT

The pilot plant is installed in a concrete building, 35 feet lo

by 19 feet 6 inches wide, with a roof of corrugated sheet me

sloping from 22 feet to 15 feet above the concrete floor. An

jacent concrete building, 22 feet 6 inches long by 18 feet wi

with the roof sloping from 23 feet to 14 feet high, houses

preparation equipment . Thi s equipment consists of a corruga

roller mill and a flaking mill for cracking and flaking the see

beans, or kernels in preparation for extraction. Nea r th

joint buildings is a solvent storage building of similar constr

tion.

The layout of equipment in the preparatioii and extracti

buildings is shoi5 n in Figures 1 , 2, and 3.

1753



1?54 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 4

r1

VAPOR

DETECTOR Ii-F L O O R P L A N

KENNEDY PI LOT SOLVENT EXTRACTION PLANT

Figure 1

The Kennedy extraction syst,em is designed around the Ken-

nedy extractor , a cross section of which is shon-n in Figure 4.

The continuous extractor consists of a series of enclosed ex-

traction chambers or sections; into each of these is fitted an im-

peller wheel assembly for moving the solid materials through

the liquid. Each impeller wheel assembly consists of a n en-

closed hub (the lower portion of the hub is partially submerged

in the liquid), four curved blades of perforated metal, an d a shaft

extending through bearings in th e sides of t he extractor n-alls.

Th e impeller wheel assemblies are driven fr om th e outside by a

common drive shaft through a xyorm and gear arrangement.

SXTRACTIOS AK D RECOVERY PROCESS

The process is as shown in Figure 5. Khen the solid material

being processed is required in flake form for extraction, IL 1sfirst put through tlie corrugated rolls of the cracking mill. Se xi ,the moisture content is adjusted to give the best, flaking prop-erties, a nd then t,he ma,t,erial s flakcd i o the desired thiclrness bypassing it one or more times through the smooth rolls of th eflaking mill.

The material, reduced t o the most suitable form and size forextraction, is placed in t he feed'hopper of the Kennedy extractor.From here, controlled quan titi es a re fed a t a COnSTant rate b>- afeed screm conveyer into the first extrac tion section of tlie cx -tractor. The material then is carried through the extrac-to r in countercurrent flow to t.he solvent.

Each portion of immersed solid material in a section iscollected by an ,impeller blade and carried through theliquid in that section. As the solids are carried up thecurved wall of that section, they are slightly compressedbetween the wall and the curved blade to form a wedge,which is lift ed above th e liquid level and sloughs off theblade into the next section. Thi s slight compression anddraining, through lifting the solids above the liquid level,reduce t8he mount of ent rain ed liquid carried over to t,hesucceeding section.

On striking th e liquid surface in the succeeding section,the wedge readily breaks up and disperses. Th e solidsimmersed in th e liquid of thi s section as distinct particlesare again collected by an impeller blade an d moved th roughthe liquid.

The cycle in each section of dispersion, immersion, andcollection of the solid in the liquid, of movement t,hroughthe liquid, and of the compression, lifting, and draining ofthe solids is the basis of the intimate and thorough con-tacting betm-een solid and liquid for exhaustive extractionof solute.

The extracted solids arc gravity drained of a good partof the entrained solvent while being carried up the dragchain conveyer, and then are dropped into a collecting canwith a perforated false bottom for separating additionalliquid drainings.

The drained batch fed int.0 thdryer n-here soporization t akscmicontinuouseither atmospvacuum conditivapor is carrieddryer through jacketed filte

Here, in passina cloth-covererated metal the vapors deentrained dusflowing int,o heing system.

The solvent fextractor is pumthe weigh tanksp o r t i o n i n gthrough the tuheat exchangeby controlled hor steam flowshell side, theleaves a t the deperature for eIt then flows

drag chain convtion of the extr actor at. an inte rmediate level and givwash t,o h e extracted residue on t ,he lower flights of the as they are carried upward. The solvent collects at ththe conveyer, which serves as the last wsidue extraction, and then overflow from seciion t,o section of the in countercurrent movement t,o the solids.

The solvent, containing the extracted material in leaves the filter section with a small content of fines, icomparable t,o th c amount of fines in th e solid feed mamost of the smaller particles are carried along with thsolid residues. A large portion of th e fines entr aineliquid are removed in the self-filtering operation in t he as the solvent fiows through tlie solid materials betxeenof the extractor ; also the coarser fines settle out ' of the liqsections (particularly the filter section) and are carried b

On leaving the extrac tor, the extract liquor flows by grathe miscella receiver; from the bottom of the receiver it ,iby a proportioning pump through a laboratory SparkHere the remaining fines are deposited on the prccoatdisks covering the filter plates. The fi ha te flo~vsntotank.

The solvent recovery unit of the pilot plant was deseparate vater-immiscible solvents from nonvolatilextracts, such as is normally the case in extracted vegeand animal fat recovery operations. Extractions involvimiscible solvents, or volatile or solid extracts, requirrecovery equipment, axmilable in t,he laboratories andtion pilot plant elsen-here in the VuIcan plant.

In . norcoveries.

Figure 2. View in PreparationR iiilding

cumulai'edof solvenliquor is pcarried byfrom the wat a constausually tmore time

of inflow to-throughthtube of therising-filmtor and thentrainmerator. Frthc vaporvent iscarrcondensersliquid, ofcentrated 90% extratemperaturu u m o pflows to tt h e s t rcolumn.



September 1948 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 1755

Figure 3. View i n Extraction Building

Here, the liquid flows down through the packed strippingcolumn (filled with Raschig rings) in countercurrent flow tostripping steam. Th e stripping column is jacketed so that theheat required to vaporize the residual solvent may be addedthrough the shell of the column. Th e vaporized solvent and thestripping steam pass through an entrainment separator abovethe stripping column and from there to the condensing system.Th e solvent-free extr act flows into a vacu um oil receiver.

Th e condensate is collected in one of two vacuum con densatereceivers and flows from th em t o a decanter for separating waterfrom solvent so tha t the latter may be re-used. The vapors fromthese condensers flow t o a large water-cooled, tube-in-shell ventcondenser before venting to the air. When the condensation isunder vacuum, th e vapors are carried through a steam jet ejectorto t he vent condenser.

SPECIAL DESIGN FEATURES

In the pilot plant all items that contact solvent, miscella, oroil are made of type 316 stainless steel. This materia l was chosen

because it is resistant to the widest variety of liquids, solids, or

vapors th at may be involved in the processing.

The extractor throughput time can be varied from 30 to 90

minutes by adjusting the variable speed drive. The capacity of

the extractor ranges from 1 to cubic foot per hour of solid

material, depending on the throughput time. With the usual

oil-bearing materials, having densities from 20 to 30 pounds per

cubic foot, this amounts to about 7 to 30 pounds per hour. The

feed screw and drag chain conveyer are synchronized with the

extractor drive. To meet special requirements outside the op-

erating ranges mentioned, adjustments and changes in the ex-

trac tor can be made readily by changing sprockets and gears.

The number of sections in thc pilot extractor are fixed. However, means are available to de termine the proper numb er of sec

tions for a commercial machine. To decrease the number o

effective extraction sections, the feed hopper assembly of the

pilot unit may be moved to discharge into an intermediate sec

tion. T o increase the numbe r of extracting sections, the extracted

solids discharged from one run may be used ns th e feed materia

for a subsequent run.

Th e solvent feed rat e can be varied froin 0.5 to 11 gallons pe

hour by adjusting the solvent feed pump. Th e solvent ra te

used depends on the concentratio n of solute desired in th e ex

trac t liquor and t he am ount of solvent carried from the extracto

by the wet extracted material.

In the design of the vacuum dryer, the advantages of operating

on a continuous basis were counterbalanced by the high cost of

devices fo r continuously charging and discharging the materiainto and from a vacuum. A compromise between b atch and con

tinuous operation was obtained by uring a continuous dryer with

a throug hput cap acity of about G times that of the extractor and

providing vapor-tight feed and discharge hoppcrs with cnough

volume to allow an 8-hour run of wet extracted material. Th

holdup time in the drying section can be varied from 20 t o 9

minutes.

The oil and solvent recovery system, when operating at 1

inches of mercury absolute pressure, can recover from 3 to 1

pounds of oil per hour, depending on th e original concentra tion

of oil in the miscella. Both th e evaporator and stripping column

heating jackets are piped to allon the use of either steam or ho

water as a heating medium.



1756 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 40,

LXTRACTFDSOU@ /

RECEIVER__Figure 4. Schematic Drawing of L ulcan P i lo t Plant Extractor

Solids impeller dimensions: 14 impellers are 8 inches in diameter X 6inches in width: 1 impaller is 11 25 inches in diameter X 6 inches i n w.idth:each impeller has 4 blades of 24-gage stainless steel, perforated with

1/16-inch h ole s, on '/sa-inch cent ers

The introduc tion of complete an d modern safety eyuipnient,

and practices mas one of the foremost considerat,ions in the de-

sign of the plant. Electrical equipment in the extraction and

solvent storage buildings is of Class I, Group D rating. A flam-

mable vapor detector samples the air in sequence from eight

critical points in the pilot plant. If the flammable solvent con-centra tion in t,he air reaches 40% of t he lower explosive limit, an

alarm sounds, all motors are shut' off, vent louvres below the

windows autoinatically open, an d th e vent,ilation blower changes

rhe air i n the building 30 times an hour instead of th e 10 times an

hour for normal operation.

All equipment, mctal supports, and window frames are

grounded positively. TThcncvcr flanimahle solvent is present, in

the building, only nonspariting tools are used and only minor

repairs are permitted. Other safety features, impor tant but

beyond t>he cope of t,his paper, were incorporated in the extrac-

tion plant'. As careful a safety engineering j o b was done for the

preparation and solvent.storage buildings.

OPERATION O F THE UNIT

The pilot plant' was operated for the first, 6 months on one,

two, an d occasionally three %hour shifts per d ay for a 5-dag XI-eek.

Hoviever, the demand for applying the Kennedy system to an

increasing number of extraction problems has necessit,ated a 3-

shift, 24-hour per day operation of the pilot plant since the first

of this year. Operation for 5 days per week has been continued,

except on special, urgent occasions.

The extraction pilot plant is under the direct control of the

head of the Research and Development Depar tment; he is re-

sponsible also for the operation of th e Dist'illation Pilot Plan t

and Laboratory, a nd the Fermentation a nd Biochemical Labora-

tory of the Vulcan organization. The engineers of the Kennedy

Extraction Division work closely with him in coordinating and

scheduling the pilot pla nt runs. Close contact is kept also with

representatives of various companies interested in t he specific

runs or for whom th e investigations are being made.

They

are assisted by chemical engineering students of two or more

years' training in the cooperative course at the University of

Cincinnati. Th e shift supervisor and an assistant operator are

assigned for each shift t,o run the plant,. Another assistant is

scheduled each shift to carry out th e required analyt,icalwork onsolid and liquid samples of materials, taken prior to and after

processing, or from intermediate processing steps. Anot,her engi-

neer on the day shift correlates these dat a and prepares th e formal

reports.

I n starting up, th e solvent is pumped from a drum outside the

building: by a hand pump into one of the weigh tanks. The ex-

tractor sections are filled wit,h solvent. Then wit,hout further

solvent flow, the snlid material is fed int o the extractor. -4fter

The shift supervisors are graduate chemical engineers.

the solids work through t,lie ext,ractor and st

discharge, solvent flow is resumed at the req

rate and proper temperat,ure. This start-up

dure is used t o build up equilibrium concentr

quickly. Another 2 to.4 hours are required

mally to reach dynamic equilibrium in the e

tor. Runs are then continued from 4 to 24

depending on what specific information or quof product is desired. The recovery syabembe operated concurrently with t'he extractor, b

frequently operated during the clean-out per

the preparatory period for a succeeding ruii.

DATA OBTAINED

During extraction operation, hourly weight

ings ar e taken for solids and solvent feed rate

extrac t liquor and solids residue discharge

to obtain material balances. Samples o

liquid and solid discharged materials also are taken h

for analysis t o obtain a niaterial balance for the extract ma

Fines remaining in th e ex ti~act iquor can he measured b y w

ing the cake of th e filter plates af te r the run or, better, by e

ing a gall011or more liquid saniple during the run for labo

filtration, drying, and iveighing.Liquid and solid saniples at intermediate stages of extr

are taken through t hr quick-opening st~mpli ng x t s lo

above the junction point between Pach pair of extractio

tions. These saniples are taken only at the end of each

avoid upsetting material equilibrium during that run.

solid samples are drained t o a uniform extent by placing o

sorbent paper toweling before analysis. The liquid sanipl

settled or filtered free of fines before analysis. Analyses o

material and final extracted material are run in t,riplicate.

centrations in intermetliat,e srctioris are usually th e res

single analysis.

The recovery equipment, both for the e stra cttd residue an

ext,racted material, is operated chiefly to duplicate, on a

tinuous basis, cornniercial operations to ensure t,hat comp

product quality may be attained. Ternpcrature wid va

conditions are measured and maintained cloaely.The concent,ration of th e ext ract liquor after evaporatio

before stripping is an example of t>hegood agreement be

theory, pilot plant operat,ion, and coinmercial design.

laboratory equilibrium data for a typical vegetable oil in a

petroleum solvent (Sj, the equilibrium concentration at. 1an d 20 inches of mercury vacuum is 9394 oil. In the des

a commercial installation for these conditions, a value of

oil concentration was used. The pilot plant evapora tor,

operated at this given temperature and vacuum, consis

discharges a concentrated oil-solvent liquor containing Fro

to 927, il.

For each series of runs made on a given type of ma

(covering a period from 2 days t o a month or more),

search Department report is prepared, This report pr

briefly but thoroughly t,he n-ork accomplished, the dat a ob b

and the conclusions drawn. Da ta usually are prepared

lows: a general summa ry of conditions and results for eac

an over-all material balance sheet of input and output

extract,or; and the analytical results on concentrations of

in solid and liquid at, intermediate and t erminal points of t

tractor . An over-all solube balance sheet is the n pres

Examples of thcse dat a sheets are shown in Tables I to IV .

Charts which show the solute concent,rations plotted a

extractor section number on semilog paper a re included wi

da ta sheets. Such charts are valuable for design purpos

ext,rapolation or inte rpolation of the curves indicates the

of increasing or decreasing the number of extraction sec

Comparison between curves shows the effects of changes



September 1948 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 17

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DIAGRAMMATIC FLOW SHEET

KENNEDY PILOT SOLVENT EXTRACTION PLANT

Figure 5

in the operating variables from one run t o another. Typical

charts are shown in Figures 6 an d 7.

When quality determinations are made on the solvent-free

extracted residues discharged f i om the dryer or the recovered

solute from the distillation unit, these data are recorded in the

report. Generally material or heat quantit y measurements

are not made on either the dryer or distillation unit operations,

as these pilot units were not designed for such purposes. This

information is unnecessary for design of commercial units be-

cause accepted and pro ved metho ds of ca lculation from chemical

engineering principles are available. However, careful control of

pressure and temperature is carried out in the drying, evaporat-

ing, and stripping so th at th e quality of the products obtained

may be an indication of performan ce in large commercial installa-

tions of similar design a nd under t he same operating conditions.

EVALUATION OF PILO T PLANT WORK

After 10 months of operation, a review of th e results shows tha t

the extraction pilot plant has lived up to all expectations and

justified th e purposes for which it was built. I n operations with

a number of different extractable solids and several solvents, it

hm proved versatile and flexible. It has made apparent the

extractive actions of the Kennedy system with sufficient clarity

t o give a good indication of their effectiveness even when extra-

polated t o large scale operation It has supplied the basic infor-

mation on a large number of extraction pioblenis to permit d

sign of commercial installations with g uaranteed performan ce.

Approximately 115runs on over 20 different kinds of solid m

terial (some prepared several ways) and using various solvents

solvent mixtures have been completed in this continuous pil

plant during operation for less than a year. Materials oi veg

table origin from which oils have been recovered include so

beans of vario us flake thickness, g round or flaked cottonse

(bot h cooked and uncooked and containing a wide range of fin

content), casto r bean flakes and pomace, sunflower seed, and fla

seed.

Tallow and grease have been extracted from various packin

house materials containing from 5 to 607 , animal fat. Anim

tissues processed include both pressed and unpressed crackling

steamed bones in the dry and wet states, and dried pancrefines. Wate r extracti ons have been accomplished on coffe

seaNTeed, and paper pu lp. Special extrac ts, such as caroten

chlorophyll, and cholesterol have been recovered in the pilot plan

Petroleum fractions, acetone, alcohols, trichloroethylene, an

hot and cold water, as well as mixed solvents, have been used

extractants. Granular, powdery, flaky, gelatinous, fibrou

stringy, and pulpy material all have been handled readily in th

extractor.

The settling action in th e sections of the extractor, particular

in th e filter section, and t he filtering action of t he solids on th

TABLE. GENER.4L S U M M A R Y FOR RTJX’

Solvent ratioSolvent feed temperature, F.Extractor temperature F.Oil in extracted meal (dry basin). %Oil in miscc”- oI-... . ~ ~ 5 U * , ,o

Fines in unfiltered miscella, %Fines in unfiltered miscella (after settling 1 l i r . ) , %Solids in drained meal, % . . .

- il in mRrc bX 100)

1/22/48

459 .540.932.05.61.2

14.91 .57

0.724.60 . 30.04

51

98.5

135135

TABLE1. SUMMARYF AN.4LYTICAL RESULTS=Riin b. -~~

1 2’ 3

2 .2 37 .3

31 15 4. 8

43.4O 11.3 4 .5

1.14 0.61 0,0

-.-1 2’ 3

2 .2 37 .3ater (as received), %

Fat. % 31 15 4. 8

Feed

MiscellaFat, % 43.4O 11.3 4 .5

Fines, % 1.14 0.61 0,0Fat in,mrtrc, %

Section 1 40.0 11.7 2 .43 33.0 8 . 6 1.75 21.3 5 . 1 1 .07 14 .4 2 .9 0 .99 7 .4 1 . 6 0 .6

11 4.0 0 .82 0 .6

13 1 .7 0 .49 0 .4Fat in final mar0 %Fa t in solvent drhned from marc, % 0 .22 0 .46 0.4

1 . 5 0 . 6 0 . 5

Q Data sheet taken from research department report on extraction ofrolled and cooked cottonseed meats as normally prepared for hydraulicpressing.

b Lb. of oil per Ib. of dr y oil-free meal. :amed bone.



1758

60

10

30

10

I O

8

6

5

"

3

2

I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 40

H M L i E i U R A T E 7. 1 L B E . / H R .

S O L V E K T F E E D R l T E 17.3 L B S . l H R .

E X T R A C T O R TE"PER4TURE 128°F.P E R C E Y i O IL l i l M E A L U H ? R I BASISH E A L E N T E R S A T 7. 7 P E R C E N T kdTsR

H E A L DATA FO ? H E A L L E A Y I N O S E C l l O Y H 1

1.0

5

6

5

Y3

I 6 8 12 I Y

E X T R A C T O R S E C T I O N

Figure 6. Extraction Profile on Rolled andUncooked c'Bollie" Cottonseed Meats

Flake thickn ess, 0.013 0.0059 inoh; oi l in micella leavingextractor, 24.6%

counterflowing liquid especially during the m ovem ent from section

to section, keep the solid fines of the miscella to a minimum.

Normally th e tines content is appreciably below 1% by weight of

the miscella leaving the extrac tor; this indicates ready removal

of the fines in large scale operations by ordinary clarification

methods .

A s a source of design da ta for comniercial installations, the

pilot plant has proved invaluable. Test runs on extractable ma-

terial, prepared in various ways, permit determinztion of th e

most suitable preparation procedure for extraction of the mate-

rial. Similarly, the optim um extraction temperature, the mini-

mum acceptable throughput time for the solids, and the best

solvent to solids feed ratio may be determined for each inaterial

by varying these extraction factors.

TABLE11. SUNIVIARYO F hI.4TERI.4L BALANCES~

Run

1 2 3 4_ _ _ _ _ _ _ ~ _ _ _

InputFeed meal Ib./hr . 5 . 9 9 .1 7 . 9 6 . 2Solvent, ld./hr. 13.0 18.7 16.7 13.6

Total, Ib/hr. 18 .9 27 .8 24 .6 19 .8

Misoella, Ib./hr. 8 . 6 13 .2 1 4 . 3 9 . 2Wet meal Ib ./hr. 8 . 4 10. 3 7 . 9 8 . 8Freesolv&drainedfroin\rermeal , lb ./hr . 1 .2 2 . 5 1 . 6 1 . 6

Total, Ib./hr. 18 .1 26 .0 23 .7 19 .6

Input-output Ib./hr 0 . 8 1 . 8 0 . 9 0 . 2

a Data sheet on over-all material balance f o r extraction of various prepa-

b Material unaccounted for is vented solvent-usually high for pilot op-

o u t p u t

Material unaccounted for , % b 4 6 4 1

rations of flaxseed.

erations.

Ru n b

1 2 8

Input

ou tpu tOilin meal, lb./hr. 1.0 5 0.82 0.74

Oil in rnisella lb./hr. 1.02 0. 81 0. 72

0ilinfreesolventd;ained f roin marc, lb./hr. 0.002 0.0005 0.0005Oilin drained marc lb./hr. 0.02 0.01 0.003

Total output, lb./hr. 1.04 0.82 0.72

Input-output lb./hr. 0.01 0 0.02Materi al unaccounted for 1 0 3

a Da ta sheet on oil balanoes for extraction of soybeans.b Run 1 = flake thickness, 0.012 inoh. run 2 = flake thickness, 0.0098

inch; run 3 = flake thickness, 0.0064 inbh.

I I - I h C T S i S E C - l ln

Figure 7. Extrac tion Profile for Partially PressMeat Cracklings

As a denionstratiori unit fo r the benefit of the opera

engineer of the Vulcan Copper and Supply Company, a

as visiting represen tative s of othe r companies, w ho vi

operations through the glass top and the opened sample

the pilot extra.ctor exhibits the easy handling of t he m

being tested. The extraction cycle in each section can

served and results compared with those obtainable in a c

cia1 extractor to provide convincing evidence that th

scale unit, of similar construction and und er identical op

n d l give as thorough an extract'ion and as concentrated

tmractiquor a s t'his pilot extract'or.

h arge amou nt of work has been completed in this pilo

more remains to be done. The schedule for this extractio

is filled for the n ext 3 mont hs with enough work on new m

tentatively considered to carry the program through thX.uns cont'emplated include test s on peanuts, copra, an

kernels. These runs are expected to show that each o

high oil-content materials can be thoroughly extracted w

preliminary pressing operations. It is hoped that suficie

can be allotted for thorough and basic st,udies on a given m

with careful variat'ion of all the extraction factors t,o per

development of a general extraction theory.

Through this work, ompleted and proposed, the pilot

proving that continuous, countercurrent extraction is no

cialized process for a imited number of carefully prepare

rials, bu t tha t it is a unit' operation of general application

t,ractable solids.

ACKNOWLEDGMENT

Credit' is due Newton J. Krug for the mechanical des

supervision in t'hc fabrication of the pilot extractor. Th e

acknowledge with full appreciation the expert work of W

R. Ludlia, head of the Research and Development Depa rt

Vulcan Copper and Supply Company, and his assistan

ticularly Robert E. Benge and Gordon A. Hughmarlr, f

skilled supervision and operation of the extraction pilo

and their preparation of the Research Departmen t reports

LITERATURE CITED

(1) McIiinney, R. S. , Rose, W. G., and Kennedy, A. B., IN

( 2 ) Pollard, E. P.,'ix, H. L. E . , an d Gnstrock. E . A . . b i d . ,

RECEIVE D ay 10, 1948.

CHEM.,6, 138 (1944).

(1946).

Countercurrent Liquid - Solid Extraction - The Kennedy Continuous Pilot Plant

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Transcript of Countercurrent Liquid - Solid Extraction - The Kennedy Continuous Pilot Plant