THE EXTRACUON OF TANNIN
FRC*1
WASTE WESTERN HELOCK BARK
0V
W LL AM P
I
I
I
UAW
THESIS
A
SUDMITTED TO THE
EGOH
STATE CCtLE(E
IN PARTIAL FULFILLMENT
OF
THE REQUIREMENTS FOR THE
DEGREE OF
CHEM CA L ENG NEER
I
JUE
I
1944
APFROVED:
PROFESSOR OF CHEMICAL ENGINEERING AUO
HCAC OF DEPARTMCNT OF CHEMICAL
EsP4Ecnuc
CHAIRMAN OF SCHOOL GRADUATE COMMITTEE
CHAIRMAN OF STATE COLLEGE GRADUATE COUNCIL
III
ACKNOLEDGEI!T
THE AUTHOR IS DEEPLY INDEBTED TO
OF RESEARCH,
I<IND
.
R. S. HATCH, DIRECToR
PULP DIVISION, WEYERHAEUSER TIMBER COMPAWY, FOR HIS
PERMISStON TO DISCLOSE THE RESULTS OF THIS INVESTIGATION.
CONTEI\ffS
PA G E
INTRODUCT ION
T
RA
MATERIAL
3
DESCRIPTION OF THE PROPOSED PROCESS
7
ANALYTICAL METHODS
I
DESCR$PT1ON AND OPERATION OF THE PILOT PLANT
14
I
CONTINUouS COUNTERCURRENT EXTRACTION
BATCH COUNTERCURRENT EXTRACTION WITH WET BARK
31
BATCH COUNTERCURRENT ExTRACTION USIF4G DRY BARK
41
SUMMARY OF PILOT PLANT OPERATION
HEMLOCK EXTRACT AS
A
TANNING AGENT
45
48
PRE-.CONSTRUCTION COST ESTIMATES
49
LITERATURE CITED
58
V
i
LLUSTRAT ors
i
PAGE
FLOW SHEET OF
RoosEü
TANNIN EXTRACTION PLANT
CONVERSION CuRvE or ° BARKOMETER TO
¡O
OvEN DRY
¡3
SoLlos
FLcv SHEET OF PILOT PLANT USING CONTINUOUS GRAVITY-
15
FLOW EXTRACTION
CROSS-SECTIONAL VIEW OF bARlKL LEACH TANK
FLcv SHEET
OF
PILOT PLANT USING
ATCH EXTRACTION
¡6
35
SOLIDS PICKUP CURVE FOR WASHED WET BARK
36
SOLIDS PICKUP CURVE FOR WASHED AND DRIEn BARK
43
ThE EXTRACT ON 0F TA NN IN FROM WA STE WESTERN HEMLCCK eARK
I
I
THE BARK
0F
NTRODUCT ON
WESTERN HEMLOC[
KNOWN, ALTHOUGH UNDEVELOPED, AS
A
(TSUGA HTEROPHYLLA) HAS LONG BEEN
SOURCE OF TANNING MATERIAL.
This LACK OF DEVELOPMENT STEMS CHIEFLY rAOM THE HIGH COST OF
OBTAINING THE BARK
IN A
USEAGLE FORM AT THE LEACHERY COUPLED WITH THE
EXPENSE OF TRANSPORTING THE EXTRACT TO THE EASTERN TANNERIES.
UNCCR THESE HANDICAPS1 WESTERN HEMLOCK EXTRACT COULD NOT 00MPETE WITH OTHER COMST$C OR FOREIGN COURCES AND SHOW AN ATTRAcTIVE
PROFIT.
ADOUT TEN YEARS AGO CHARLES C. SMOOT AND RALPH W. FREY OF THE
UNtTc
STATES DEPARTMENT OF AGRICULTURE
C4)'
MADE AN EXHAUSTIVE SURVEY
COVERING ALL OF THE PHASES OF THE PRODUCTION OF TANNIN EXTRACTS FROM
THE WASTE BAiK AND CONCLUDED THAT IT COULD BE DONE COMMERCIALLY AT
PROFIT, CUT THAT THE MARGIN
IN
ADDITION1
HEMLOCK £ARK
IT
EXTRACT ALONE,
LEATHER TANNED WITH ANY ONE
IN
BE
SMALL.
WAS SHOWN THAT THE LEATHER TANNED WITH WESTERN
BRACHO EXTRACTS, WAS EQUAL
NUMBERS
WOULD
A
OR
OR
OF
IN COMBINATION VITH CHESTNUT OR QUESLIGHTLY SUPERIOR IN MOST RESPECTS TO
THE OTHER EXTRACTS.
PARENTHESIS REFER TO LITERATURE CITED, P. 58.
2
DESPITE THIS ENCOURAGEMENT
JD
INTEREST WAS AROUSEO
AND THE
MATTER HAS REMAINED DORMANT UNTIL ThE PRESENT TIME.
AQOUT
YEAR AGO THE EVERETT MILL OF THE PULP Dtvtsiot
A
WEYERHAEUSER TIMBER COMPANY STARTED THE OPERATION OF
LOG BARKER
(3)
A
OF THE
NEW TYPE PULP
WHICH THE BARK WAS CLEANLY STRIPPED FROM THE WHOLE
IN
LOG BY A HIGH PRESSURE JET OF WATER.
FOR THE FIRST TIME LARGE QUAN-
TITlES OF ALMOST WOOD-FREE BARK WERE AVAILABLE AT EXTREMELY LOW COST.
HILE
(T
NUT AS RECENT AN INVENTION AS THE HYDRAUL1O bARKER,
IS
SPRAY DRYING UNDER VACUUM
IS
NOW REACHING FULL DEVELOPMENT.
By THIS
METHOD, SOLUTIONS OF HEAT-SENSITIVE SUBSTANCES, SUCH AS TANNIN, CAN
BE CONVERTED TO
SHIPPED AT
A
A
DRY POWDER Al
A
LOW TEMPERATURES.
This POWDER CAN BE
MINIMUM COST AND DISSOLVED AT ITS DESTINATION FOR USE
IN
LIQUID FORM.
THE ADVENT OF THESE
INNOVATIONS SHOULD SERVE TO OFFSET THE TWO
BARRIERS TO THE SUCCESSFUL ESTABLISHMENT OF
A
TANNIN LEACHERY IN THE
PAC FIG 1ORTHWEST.
I
THIS PAPER
IS
THE RESULT OF EIGHT MONTHS INVESTIGATION TO SUO-
STANTIATE SUCH AN ASSUMPTIUN.
3
MERAL
ThE RAW
ALTHOUGH MANY MILLIONS OF BOARD FEET OF WESTERN HEMLOCK ARC
REQUIRED FOR THE PRODUCTION OF PULP WOOD AND LUMBER EACH YEAR
IN
THE PACIFIC NORTHWEST, THE 6ARK IN THE WASTE FROM THE MILLS IS MIXED
WITH WOOD SUBSTANCE TO SUCH
46
WOOD,
3Y WEIGHT OF BARK ANO 5
iARK ANO
T4E
OEGRFE THAT IT
IS
UNUSABLE FOR TANNIN
SMooT AND FREY (4) REPORT THAT OF TWO SAMPLES, ONE CON-
EXTRACTIONS
TAINED 4l
A
AND THE
OTHER CONTAINED
WOOD.
!ÌOOD
ITSELF CONTRIBUTES NO TANNIN ANO,
IN FACT, ArJoRÜS
SOME OF THE TANNIN FROM THE EXTRACT.
TdEE
IS
OF SEPARATION OF THE W000-2ARK
NO PRACTICAL
MIXTURE, AND ITS VALUE AS
A
SOURCE OF TANNIN IS
NIL.
THE ONLY OTHER FEASIBLE SOURCE OF DARK, UNTIL NOW, HAS BEEN
THAT
PRODUCED BY OLD-FASHIONED HAND PEELING METHODS.
BC SPUDDED OFF AT THE LOGGING SITE,
CXPtNS
OF CETTINQ
IT OUT OF
IN
THE WOODS
THE BARK CAN
WHICH CASE THE DIFFICULTY AND
IS
ENCOUNTERED.
AN ALTERNA-
T1VE METHOD IS TO ORINO THE UNBARKEI LOG TO THE POND OR LOG DUMP WHERE
THE BARK CAN BE SPUDDED OFF.
MOST IMPORTANT BEING THAT
A
THE
LATTER HAS
ITS DRAWBACKS ALSO; THE
GREAT AMOUNT OF BARK
IS
LOST IN THE LOG-
GING OPERATION AND IN SUBSEQUENT HANDLING.
F3OTH
METHODS ARE HANDICAPPED DY THE SLOWNESS AND COSTLINESS OF
HAND WORK, AS WELL AS EY THE FACT THAT THE DARK
PEEL ONLY ABOUT HALF OF THE YEAR.
RUNS FROM TWELVE TO FORTY
INCHES
IN
IS
LOOSE AND EASY TO
ADDITION1 THE USUAL PULP
LOG
IN DIAMETER V1TH THE AVERAGE NEARER
4
THE LATTER FIGURE.
THE PEELING A
THIS GREAT WEIGHT MAKES HANDLING THE LOG DURING
POULEM.
ALL OF THE ACOVE FACTORS COMOINE TO FORM THE OUSTACLE WHICH
HINDERED OR PREVENTED EXPLOITATION OF THE WESTERN HEMLOCK AS
OF TANNING
MATERIALS.
{3ARKER SUPPLIES ALL OF THE E3ARK
PORTATION AND STRIPPING
IS
AS A t3Y-PROOUCT WHOSE COST OF TRANS-
IS
LOSSES IN LOGGING DECOME
LOV
AND THE
OF THE
THE
TIME OF YEAR.
VOLWZ HANDLED
IS
SO LARGE THAT
INCONSEQUENTIAL.
THE SUPPLY OF PULP WOOC IN THE
ESTERN
BE INEXHAUSTIBLE.
THE DARK COMES OFF
BORNE UY THE PULP LOG.
LOG COMPLETELY AND CLEANLY REGARDLESS
RATIO OF WOOD-T0-E3ARK
AND
SOURCE
CONTRAST TO ALL FORMER METHODS OF GARKINC, THE HYDRAULIC
IN
THE
A
iEMLOCK
iORTHWEST CAN ALMOST 0E SAID TO
IS A
WITH THE POLiCY OF SUSTAINED YIELD
RELATIVELY QUICK GROWING TREE
IN EFFECT,
THERE SHOULD
NO
13E
PROBLEM OF SUPFLY.
PRO-
A SURVEY OF THE BARK AVAILALLE AT THE MILL SHOWED A
DUCTION OF THE DARKER TO BE 4) TONS OF OVEN DRY DARK.
PULP BASIS, THIS AMOUNTS
TO
APPkOXIATELY ONE TON
REDUCED TO
OF DRY BARK
A
PER SIX
TONS OF PULP.
THE BARK
TO HOG FUEL.
GRINDER.
ISSUING FROM THE CHIPPING PLANT
IN
IS
IN A
FOtM SI'ILAR
THIS CONDITION IT CAN BE CONVEYED DIRECTLY TO THE
THERE MUST BE NO DELAY
IN
PROCESSING THE
BAR)< AS
FERMENTA-
lION BEGINS ALMOST I1MEDIATELY WITH FAVORALLE CONDITiONS.
THE
SEPARATED.
WOOD
IN THE BARK 13 PRESENT AS SLIVERS, WHICH CANNOT BE
HOWEVER, THE PERCENTAGE
IS
NOT LARGE ENOUGH TO BE MUCH
5
OF A
HANDIOAP.
TABLE I PRESENTS THE ULTIMATE ANALYSIS OF THE BARK OVER THE
PERIOD
IN
WHICH THE PILOT PLANT WAS
THE SALT CONTENT OF THE BARK
BARK FROM LOGS
SENTS
IN
A
AN UNDESIRABLE PROPERTY
COMPLICATION WHICH WILL 6E EXPLAINED
IN
IT
OF
PRE-
GREATER BETA IL LATER
THIS PAPER.
OF OTHERS
THAT
TURE-FREE BARK
S
IS
OPERATION.
THAT ARE FLOATED IN TIDE WATER TO THE MILL.
SMOOT AND FrEY
I
IN
A
IS
(4)
CONCLUDED, FROM THE
FAIR AVERAGE VALUE
15.5%.
OF
THE
IR
OWN
DATA AND THE DATA
PER CENT TANNIN
lu CONTRASTJ THE AVERAGE
VALUE
IN MOIS-
IN TAELE II
6. 15%, A RE DUOT 10W OF SOME
APPARENTLY THE MOST SOLUBLE TANNINS ARE LEACHED
WHILE THE LOGS LIE
IN THE BOOM.
FROM THE BARK
TABLE
ArALYSIS 0F H
vILcDK
BARK
I
HYDRAULIC 8ARKER
F
BARK EXTRACT
BA RK
DATE
OvEN DRY
5)
-
TOTAL SOLIDS
-
SOLUBLE SoLlos
L)
NONTANNIN
(1
(1
TAmuN
()
NACL
()
I-19-43
41.4
14.2
12.46
5.26
7.20
2-1-43
39.2
13.93
12.17
5.38
6.79
3-10-43
41.5
13.90
11.83
6.13
6.70
3-25-43
42.8
13.99
11.90
6.86
5.04
5-24-43
95.4 (DRIED)
12.32
11.01
4.42
6.59
0.295
6-7-43
92.3 (DRIED)
13.20
11.50
4.96
6.58
0.206
7-12-43
44.35
12.46
10.82
5.44
5.38
0.184
7-16-43
36.4
11.92
9.94
4.48
5.46
7-30-43
46.9
¿4.82
6.02
6.28
0.091
8-Il-43
53.03
¿3.5
12.26
5.74
6.52
0.082
8-26-43
41.8
12.42
10.73
5.63
5.10
I
0.2G2
C'
SCRIPTIO
ORSED PRESS
OF THE
THERE ARE NO RADICAL DEPARTURES
SHANK'S METHOD
OF
IN
THIS OPERATION FROM THE
LEACHING.
THE HOGGED DARK COMING FROM THE DARKINC PLANT
REDUCED TO
Ir
A
FIBROUS MEAL AND LOADED INTO
READILY SOLUBLE
LESS SOLUBLE
FLOODED
IS
IN
IN COLD WATERS
SERIES OF EIGHT STEPS
IN
THE TANNINS
NEARLY ALL REflOVED.
BUT SLIGHTLY AFFECTED.
HYDROLYSIS REACTION AND
IS
COUNTERCURRENT OPERATION.
FLOWS THROUGH THE OTHER SEVEN
WAY, AND
IS
THE SALTE WHICH
CARRIED OUT IN
HOT WATER
IS
INTO THE TANK CONTAINING THE BAR)< MOST NEARLY EXHAUSTED.
INTRC)DUCED
IT
A
IS
PILOT PLANT
IN THE
mICE WITH COLD WATER.
COLD WATERS
Tic EXTRACTION IS
A
BATTERY OF LEACHERS.
THE BARK CONTAINS NACL, LIKE THAT USED
OPERATION, THE MASS
IS
A
MECHANICALLY
IS
IS
IN
SERIES, PICKING UP TANNIN ON THE
FINALLY WITHDRAWN FROM THE TANK CONTAINING FRESHLY CHARGED
BARK.
TANNIN EXTRACT IS PARTICULARLY SErJSITIVE
TO HEAT AND
EXHIBITS
A
TENDENCY AT HIGH TEMPERATURES TO FORM CONDENSATION AND POLYMERIZATION
PRODUCTS WHICH ARE UNDESIRABLE IN THE FINISHED PRODUCT.
HIGH LEACHING
TEMPERATURES ALSO BRING MORE UNDESIRABLE NONTANNINS INTO SOLUTION,
THZREI3Y
PURITY.
TROLLED.
INCREASING ?HE SLUDGE CONTENT OF THE EXTRACT AND LOWERING ITS
Fori
THESE REASONS ALL TEMPERATURES MUST
THE LEACH TE4PERATURES
LiE
CAREFULLY CON-
ESPE(IALI.Y, MUST RE KEPT AS LOW AS
7Q0 C.
IS CONSISTENT WITH GOOD YIELDS ANO IN NO GASE ALLOWED TO EXCEED
THE EXTRACT IS ALSO EASILY CONTAMINATED
13V
IRON,
E.XTRACT
CONTAINING IRON RESULTS IN
IN
ADDTION
A
DARK-COLORED LEATHER.
TANNIN IS PRECIPITATED FROM SOLUTION BY NACL, THUS
REDUCING THE EFFECTIVE STRENGTH OF THE TANNING LIQUOR.
FOR THIS REASONS
THE DARK MUST BE THOROUGHLY WASHED DEVORE EXTRACTION BEGINS.
UNSALTED
DARK, WHEN OBTAINABLE, GREATLY SIMPLIFIES THE PROCESS BY REDUCING DILUTION AND ELI:INATING TANNIN LOSSES IN THE WASH WATER.
STRONG EXTRACT FROM THE LEACHERS
SOLIDS IN THE FIRST TWO £FEECTS OF
TRIPLE-EFFECT EVAPORATOR.
A
IS
CONCETRATED TO 15% TOTAL
LONS-TUDE, VERTICAL, FILM-TYPE,
EXTRACT DISCHARGED FROM THE SECOND EFFECT
IS COOLED TO SOLIDIFY AND PRECIPITATE THE FATS ANO
IT.
XES CONTAINED IN
AFTER ABOUT
THE COLD SUSPENSION IS PUMPED TO SETTLING TANKS WHERE
TEN OR TWELVE HOURS, THE SUPCR'ATANT LIQUOR IS PUMPED TO THE REMAINING
EFFECT AND FURTHER CONCENTRATED TO
4.
THE SLUDGE IN THE SETTLING TANKS
TRIFUGE.
IS
WASHED AND PUMPED TO
TIE SOLIDS ARE DISCARDED AND THE CLEAR LIQUOR
A
CEN-
RETURJED TO
IS
THE FIRST EFFECT WITH THE DILUTE EXTRACT.
Ir
FUTURE REFINEMENTS, NOW CONTEMPLATED, PROVE SUCCESSFUL, THERE
WILL DE VERY LITTLE SLUDC, AND THE FOREGOING PROCEDURE MAY BE ENTIRELV
ELIINATCt, VdH TFE POS5IbLL EXCEPTION OF
A
F1LTBATIuN STEP BEFORE
THE EVAPORATORS TO REMOVE THE (ARK PARTICLES.
THE PLANT IS IACE rLExICLE IN OPERATION BY PROVIDING FOR EITHER
BATCH OR QONTINOUS OPERATIGN.
THE ADVANTAGE OF ONE OVER ThE OTHER
HAS NOT BEEN DEFINITELY ESTAi'LISHCO, AND PROEAiLY ACTUAL TRIAL
COMMERCIAL SCALE WILL BE
NECESSARY 6EFOC
A
DECISION CAN
E
ON A
MACE.
FORTUN:LY,
THE SAME EQUIPMENT, WITH VERY LITTLE ALTERATION,
Is
ADAPTABLE TO 00TH, AND SWITCHING FROM ONE TO THE OTHER WILL ONLY
INVOLVE
A
CHANGE
IN
PROOCOURE.
A COMPLETE FLOW SHEET OF THE PROJECTED PLANT
IS
PRESENTED ON
PLATE A.
tu
ORDER TO KEEP THE SIZE OF THE PLANT AND THE NUMBER OF
LEACHES WITHIN REASONABLE LIMITS,
LEACH EVERY FIVE
HOURS.
IT WILL 0E NECESSARY TO DUMP
THIS WILL MEAN THAT ANY ONE LEACH WILL
CONTAIN THE SAME CHARGE FOR AN INTERVAL
OF
40 HOURS.
A
Fi-e s
b
b 4' k
Hamcp
- rt
r-
.
-
,
1.
T
a fc
0r
.
T
FLOW SHEET OF PROPOSED
TANAIIN EXTRACT PLAI'JT
P-la
C C'
J
'JE
t--
I
CV
C.
j
J
-'
_
I
F
-
I
1
F,r'L w#ish
v'.II
j
T
i-
_______
______-
FLut
Jp
J
No#c
Z.id w.sh wiTh
-
I!
__L -- __J -----
_____
-
i{ooierj
I
To
I
coo/IT?
sewc.-
To#..-».'ce
r
JTi,iqk
I
P;I'c,------, p
ÍiW
Evøpl
Trsp
Iori,T0v
M'iq heus.Si'rc7' /mbor
32.4 Tons øven dvy wehi e1 bare
4
J4,3eo
Jo 400
J-3.
.j_o,
Q./.. aff/I*cticW
Pe-toi of
wa#
CI. o#P.*5.i#
,00/.
Wiw#e#
77 K/fow4Tt o-f e/cci'ricF'3.
:3 00 4hs. 0* proc.s-s s-fr..,,
J,
PL-ATE A
A\LYTICAL ETHODS
THE WATER CONTENT OF THE FRESH BARK1 WASHED BARK, AND EX-
HAUSTED
SARI<
WAS DETERMINED BY CRYING
FOUR H)URS AT 1050 C.
lOO GRAM SAMPLE FOR TWENTY-
A
THE GRAMS OVEN DRY WEIGHT WERE REPORTED AS
PER CENT OVEN DRY WEIGHT.
THE MACL CONTENT OF THE FRESH BARK, WASH WATER, AND THE EXTRACT
AT VARIOUS STAGES WAS DETERMINED UY AN ADAPTATiON OF THE METHOD GIVEN
BY GRIFFIN (2).
IN THE
CASE OF THE FRESH DARK, THE SAMPLE WAS EX-
TRACTED1 AS OUTLIUED UNDER TANNIN ANALYSIS, AND THE SALT CONTENT OF
THE EXTRACT WAS DETERMINED AS USUAL AtJD THEN CALCULATED BACK TO THE
FRESH DARK.
TWENTY-FIVE CUSIC CENTIMETERS OF
THE PROCEDURE WAS AS F-oLLov)s:
THE EXTRACT, OR WASH WATER, TO 0E ANALYZED WAS PIPETTED
NICKEL CRUCIBLE AND WEIGHED.
INTO
A
TARCO
THE SAMPLE WAS THEN EVAPORATED TO DRY-
NESS AND REWEIGHED FOR SOLIDS CONTENT, AFTER WHICH IT WAS ASHED
IN
AN
OPEN MUFFLE FURNACE AT AÍI)UT 73Q0 C. YITH EXCESS AIR UNTIL ALL OF THE
CARBON WAS GONE.
THIS ASH WAS DISSOLVED
IN
ABOUT TWENTY-FIVE CUBIC
CENTIMETERS OF CISTILLED WATER AND SUFFICIENT
THE SOLUTION ACID TO PHENOLPTHALEIN.
WAS TITRATED WITH
j/io
I
NORMAL H2SO4 TO MAKE
THE CONTENTS OF THE CRUCIBLE
AGN0, WITH CONTINUOUS STIRRING1 TO
A
PERMA-
NENT RED COLOR USING K2CR04 AS AN INDICATOR.
THE FOLLOWING CALCULATIOS WERE MADE:
N(AaNO3) x 58.45 (EquIv. NAOL)
1000
X
CC. AGN0
-
x
lOO
=
IR
CENT NACL
12
OR,
cc.
AN03
x
0.23283
=
PER CENT NACL
=
GRAMS/LITER
A ND
PER CENT 'ACL X IO
ACL
THE TOTAL SOLIDS CONTENT OF THE EXTRACT WAS MEASURED WITH
E3AR<OMETER.
I
IS
IS A
A
A
lOO CC.
SAMPLE WAS
HYDROMETER OF STANDARD DESIGN CUT CALl-
SUCH A MANNER THAN 00 BARKOMETER
IN
SP. GR., AND
No.
GREATER ACCURACY WAS DESIRED,
A DARKOMETER
DRIED.
CRATED
Ir
A
100° BARKOMETER
IS
IS
EÇUIVALENT TO l.00O
EQUIVALENT TO ¡.100 SP. GR.
CONVERSION FOR EXTRACTS OF
L
CURVE
SOLDS CONTENT FROM DEGREES
BARKOMETER TO PER CENT OVEN DRY SOLIDS.
Ir
THE MORE EXACT WEIGHT METHOD WAS PREFERRED
TRACT WAS PIPETTED INTO
ABOUT THREE
AT
A
IOU CC. OF EX-
SPECIAL FLAT-BOTTOMED EVAPORATING DISH OF
INCHES IN DIAMETER.
THE CONTENTS WERE WEIGHED, DRIED
105° C. FOR TWENTY-FOUR HOURS, AND REWEIGHED.
RESULTS WERE RE-
PORTED AS GRAMS PER LITER OR GRAMS PER HUNDRED GRAMS, AS DESIRED.
ALL TANNIN ANALYSIS OF THE FRESH BARK, SPENT BARK, EXTRACT, AND
SALT WASHES
WAS MADE ACCORDING TO THE SPECIFICATIONS IN THE "OFFICIAL
METHOD OF THE AMERICAN LEATHER CHEMISTS1 ASSOCIATION."
WHICH
IS
THIS METHOD,
TOO VOLUMINOUS TO REPEAT IN THIS PAPER, MAY BE FOUND IN THE
CHEMISTRY OF LEATHER tVÁNUFACTURE
(7)
ON PAGES 417-423
INCLUSIVE.
¡4
CSCR
I
PT ON AND OPERA T ON OF THE P LOT PU.NT
PILOT PLANT WAS FIRST STARTED
VIHEN THE
CONTINUOUS COUNTERCURRENT PRINCIPLE.
ON THE OATCH SYSTEM.
LATER
IT
IT
WAS OPERATED ON THE
WAS REDUILT TO OPERATE
As 00TH CONSTRUCTION AND OPERATION WERE DIFFER-
TYPE, THE DISCUSSION WILL 0E DIVIDED
ENT FOR EACH
ADDITION,
I
I
¡
NE
INTO TWO PARTS.
¡N
OPERATION OP ThE FINAL INSTALLATION WILL EC SUODIVIDED
TO INCLUDE 00TH DRY AND WET BARK
I.
LEACHING,
EXTRACTION
CONTINUOUS COUNTCRCURREiT
THE LEACHING WAS DONE
IN A
LINE OF EIGHT 50-GALLON OAK BARRELS
OF
STANDARD MANUFACTURE WITH TOPS REMOVED. THEY WERE PLACED STEP-WISE
ON
A
RAMP SO THAT THE TOP OF EACH EARREL WAS ABOUT
TOP OF THE PRECEDING BARREL.
COVERED WITH
A
FOOT BELOW THE
SEE PLATE [.
EACH BARREL WAS FITTED INSIDE WITH
BOARDS RAISED ABOUT FOUR
A
A
FALSE BOTTOM OF PERFORATED
THIS WAS
INCHES ABOVE THE TRUE BOTTOM.
20-MESH STAINLESS STEEL WIRE SCREEN.
A
TWO-INCH HOLE
WAS BORED THROUGH THE SIDE OF THE BARREL JUST ABOVE THE SCREEN ANO
FITTED WITH
A
PLUG AS
HOLE, ALSO FITTED WITH
WASHOUT PORT FOR THE SPENT BARK.
A
A
PLUS, WAS MADE
IN THE
A
ONE-INCH
SIDE 0F THE BARREL JUST
ABOVE THE TRUE BOTTOM FOR COMPLETE DRAINAGE OF THE BARREL.
SEE PLATE
C.
A
TFREE-EIGHTHS INCH TUBING UNION WAS SCREWED INTO THE BOTTOM OF
COAIT/N VOUS 1MV/T''-FLOW EXTR4CT/OA/
1,
-
r - ---
r
,-s-
-
L
:-
ç3-:__
'
--
(J
L'
-s-I
JI
L
----T----*
PLATE
LB
Ñ#n,p
i'
CR055-SECT/ÖAJAL VIEW
OF 8AREL
LEACH TAN?c
Arth-c,poi Vcr+
5c7Pv1
f
I
Fro,,i
Lx.1.rac.L
rr-i
N
rÌ
il
'
Prtvcg,s
Level
vk_LevEL
______ --
LCQCi,
Rai-k Wi'c,u#
5crcert
\p
/V/IV ir
K1NaC/-/Cr7U'k'
1
7y//////// i2fi/
1IV
<n
I
!
J
ii
A!/
'
n
I
PLATE C
ToAk
THE BARREL AND
A
LENGTH
OF
"SARAN" TUBING SUFFICIENT TO EXTEND UP AND
OVER THE SURFACE OF THE NEXT LOWER BARREL WAS ATTACHED. THE TUBING WAS
PUNCTURED AT THE HIGHEST POINT
AND rr
S
ADJUSTABLE
GOOSENECK TO PREVENT
OF THE
IJ HEIGHT
SIPHONING,
SO THAT THE OVERFLOW TO THE NEXT DARREL
COULD BE GOVERNED DY RAISING OR LOWERING THE TUBING
IN
RELATION TO THE
SURFACE OF THE LIQUID IN THE BARREL TO WHICH IT WAS CONNECTED.
EVERY 3ARREL
EQUIPPED
V.AC
YJITH
A
PERFORATED WOODEN PAN WHICH WAS
PLACED IN THE TOP OF THE BARREL SO THAT THE BARK WOULD NOT FLOAT.
THIS MANNER THE TOP 1VO
CLEAR.
A
IN
INCHES OF SOLUTION IN THE BARREL WERE KEPT
COPPER STEAM COIL WAS SUBMERGED
IN
THIS CLEAR LIcUOR AND
USED TO MAINTAIN THE LEACHING TEMPERATURE.
A
GEAR PUMP AT THE OVERFLOW OF THE LOVEST BARREL ON THE RAMP
LIFTED THE LIQUOR TO THE TOP BARREL, AS ONLY ONCE
IN
EIGHT TIMES WAS
THE LOVEST FARREL THE TERMINAL BARREL IN THE BATTERY.
HOT WATER WAS PROVIDED FOR ANY ONE BARREL 3? MEANS OF
A
HEADER.
OTHER CONTAINERS WERE USED AS STORAGE AND WERE EQUIPPED WITH
A
LABORATORY-SIZE CENTRIFUGAL PUMP TO FACILITATE TRANSFER TO ANY POINT
IN
THE SYSTEM.
THE BARK GRINDER USED WAS
A
TYPICAL SWING HAMMER PULVERIZER.
THE SCREEN BENEATH THE HAMMErS WAS PUNCHED WITH HALF-INCH HOLES.
BED
3ARK WAS SHOVELED
Hoo-
INTO THE HOPPER ABOVE AND GROUND BARK WAS RE-
MOVED FROM BENEATH.
THE EVAPORATOR WAS ASSEMBLED FROM VARIOUS PIECES OF EQUIPMENT
PICKED UP FROM THE MILL SALVAGE.
CAL TANK MADE OF STAINLESS STEEL.
THE BODY WAS
A
A
5O.)-GALLof
CILINDRI-
CENTRIFUGAL PUMP WAS CONNECTED TO
ThE 000'( TO
WTHCRA
INTO THE TOP.
INGIIX THE
FROM THE t3OTTOM AND PUMP THROUGH
A WOODEN
GRATING ANDE LATER,
A
HEATER BACK
STEAM JET
A
ZRC
IAPORATOR TB flCDUCC FOAMING.
THE FE/T
ws
AOAP1tD FROM
EXCHANGER HAVING TUBES ONE-HALF
SV4GLE-PASS, STAINLESS SIEEL HEAT
A
INCH IN DIAMETER ANO ABOUT SIX FrJET
LONG.
ALL BUT SIX WErE PLU
AT BOTH ENDS TO INCREASE THE
OF THE
L1UOR PASSING THROUGH.
VAuui
ALL PIPIHO
WAS
MAtTAIN&O
JAS
VELOCITY
UY MEANS BE A
LC.
JET CONDENSER AND BAROMETRIC
OTHER
PLACEO
STREAMLINED COPPER.
EQUIPMENT INCLUDED PLATFORM SCALES, ASH CANS FOR TRANSLABORATORY
PORTING ANO MEASURING BARKS SHOVELS
GLASSWARE
ROTH FOR
ANALYSIS AJO FOR CONTROL, THERMOMETERS, GAGES, HOSES ETC.
THE OPERATION BEGAN WITH THE GRINDING OF THE BARK, WHICH WAS
DELIVERED FROM ThE BARKER IN SKIPS
WAS GPOUH& ONLY
OF THE
lis
NEEDED.
So
SCREEN BELOW THE HAMMERS
THE PERFORATIONS WAS
RELATIVELY BRITTLE,
OF
SEVERAL TONS CAPACITY.
TROUBLE WAS EXPERIENCED WITH
PLUGGING
WHICH WAS OVERCOME WHEN THE SIZE OF
INCH.
INCREASED TO ONE-HALF
WAS BROKEN
THE BARK
UP TO A
POWDER,
THE BARK, SEING
VHtLE THE
WOOD
IN THE
MIXTURE WAS REDUCED TO FINE SLIVERS.
THE CHARGE TO THE LEACHERS WAS WEIGHED OUT
THE SAME VOLUME AS
A
EÌARREL IN THE BATTERY.
TfINEO SIMULTANEOUSLY,
SHIP OF THE GROUND EARK.
TAULE
I PRESENTS
A
IN
A
CONTAINER OF
A MOISTURE SAMPLE WAS
VOLUME-WEIGHT RELATION-
03-
DES ITY
OF
TABLE
II
(OUD
FEMWCK BARK
BARK FROM TWO-DAY OLD SKIP
TEST
Vii.
OF
MOISTURE
LBS./GU. rl.
WET
LEss/Cu. FT.
No.
3.32 Cu. FT.
I
69.5
44.25
20.9
9.25
2
80.0
44.25
24.1
10.67
3
85.5
44.26
25.75
11.40
4
83.0
44.25
25.0
11.07
AVERAGES 0F TESTS 2, 3, AND 4
24.93
O. D.
I
i
REMARKS
NOT PACKED
LIGHTLY PACKED
tI
.05
BARK FROM FRESH SKIP
5
96.75
37.8
29.35
11.10
6
98.5
37.8
29.65
I
7
99.0
37.8
29.8
11.28
29.60
11.20
AVERAGES OF TESTS 5, 6, AND 7
t
.22
LICHTLV# PACKED
7
7
'7
'7
2
STCP
THREE CO"SISTEÙ OF SALT REMOVAL.
TANNERS CO"JSIDER THE
TIOM
Ñ
PRESENCE OF SALT
ucsIrm.
TANNiNG EXTRACTS AS
IT IS POSISLt THAT
THE EXTRACT SV
THE
WATER
IS
UCD
TACLE I
(5)
TANNIN.
A
POWER
0F
SALT REMOVAL STEP,
FROM LOGS FLOATEC U TIDE
FOR LAGHlNG.
IS
nEPODUCCD FROM THE WRI( OF TEMPLETON AND SHERRARD
AND SHOWS THE EFFECT ON THE SALT CONTENT OF CAtK OF PROLONGED
SOAKING
IN
ARI<
IS O[SCURE, 3UT
EEECTIVE TANNING
SOME OF THE
THEREFORE, MUST SE INTROtUCEC WHEN
REASON
T
SALT REOUCES TH
PRECIPITATING
GREAT CONCENTRA-
$N ANY
U
SALT WATER.
IT
IS
IMPROSACLE THAT PULP LOGS WOULD SF HELD
STORAGE AS LONG AS THIRTY DAYS CUT, NEVERTHELESS, THE SALT CONTENT
0F CAR< FrOM LOGS STORED ONLY
HAND COLUMN OF TASLE I
A
(PAGE 6)
FEW DAYS IS QUITE HIGi.
THE RIGHT-
INDICATES THE TYPICAL ANALYSIS OF
CARI<
AS DELIVERED TO THE LEACHERS.
To SHO
IN CONTRAST1
THE
H
StLT
CONTENT OF
MAGNIFIED IN THE FINAL EXTRACT, THE RESULTS
OF
AN
E
EXThACTIOW WITHOUT
PRELIMINARY SALT REMOVAL ARE LISTED BELoW:
TA3LE
THE OAR}( CAN
:
TOTAL SOLIDS
24.18
%
SOLUCLE SOLIDS
21.20
%
NONTANNIN
16.74
%
TANNIN
4.46
NAOL
3.28 %
TABLE
C1POS
IlION OF WESTERN HEMLCCK AFTER BEING IN SALT WATER1
(RESULTS
ON
DETE1MINA-r i
ONS
rIOISTURE-FREE oAsis)
Sow-
BER OF
SERIES NO1
III
TOTAL
SOLIDS
Pcl'\
,jj
OLE
SOLIOS
íJ
INsoLuOLES
tr\
NONTANNINS
JQJ
TANNIN
(\
1'MCL
NACL
IN
IN
ROSS
DARK
!?\
%1JJ
6
23.01
20.07
2.94
8.24
11.82
0.036
ATER 30 DAYS
8-6
26.84
24.45
2.39
8.37
16.16
.686
III. IN SALT WATER 60 DAYS
6
25.36
21.66
3.70
8.67
12.99
2.56
5
29.02
24.89
4.13
8.51
16.38
1.53
.1..
Lt..
j.
NOT IN SALT
lu SALT
IN SALT
W?tTER
WATER 90 DAYS
0.426
1.63
FROM TEMPLETON AND SHERRARD (5).
t'J
THt SALT
-IGH1V SOUJ9LX
9ARK IS
$N TI-4E
THIS PRINCIPLE
TANNIN IS NOT.
WAS
UTILIZO
WATP WHILE
IP! COLD
IN SALT REMOVAL.
AFTER THE BARREL WAS FILLED WITH f50 LOS. 3F WET1 GROUND BARKS
COLD WATER
flARI(.
THIS
SJrICINT
IN AN APOtJT
ACOED
WA
STAND FO
WATER WAS ALLOWED TO
FIVE MiNUTES, BEFORE DRAtNIN.
IOD, THE ONE-INCH PLUG
AT THE
WAS REMOVED ANÙ THE SALT WASH
EXPtATI3N
AS CAUGHT
THIS WAS REPEATED
WEIGHING AND SAMPLING.
IP'i
J
THE
ERIOO, FINALLY FIXED AT
A
SEP4
DELOW TH
CM?LETLY CCVfl
TO
A
or THE SOAKING
THE
TTO
ThE DARREL
CF
ST3RA3E BARREL FO
IN ORDER
TO
ErrEGT COMPLETE
REMO VA L.
Two
WASHINO,
WAYS OF
WAS
OONE
DARK FROM TH
WHO
MOVED
EVEN
IT
FLOODING THE
DY
MORE
HOCE
A
HELD
iN THE HAND
OF THE
THE OTHER,
IT THE HOLES
HOLE WHERE
FROM
.
'OOTTOM WASHIN6,'
IT
WAS
AG
WAS ACCOMPLISHED
IT
HELD EV
ADLE THAN
A
TANiIN IJ
THE
TWO
METHODS ARE
LISTED IN
APPARENT THAT TOP WASHING REMOVED
WAS
A
RESULT, WAS ADOPTED AS THE STANDARD
ALSO APPARENT THAT
METHOD, DUT THE LOSS OF
NOZZLE1
FRICTION.
ODTAINC WITH
THIS TA3LE IT
WAG
A
Y
ATTACHED TO THE HOSE ANO THEN INSERTED
SALT FROM THE DARK1 AND, AS
PROCEDURE.
OPERATOR,
8AOK ANO FORTH OVER THE SeRFACE OF THE PARK TO OBTAIN
COMPARASLE RE JLTS
TAi3LC
ONE, DESIGNATED "TOP
THE OARREL THROUGH THE HOLE BEThEEN THE COTTOMS.
TAPERED TO
IN THE
TRIEC.
THE BARREL CONTAINING FRESHLY GROUND
TOP BY MEANS OF
DISTRIBUTION.
FILLINC
FILLtN
'ARK WERE
;ORE TA'JNIN WAS
THE WASH WATER
REMOVED EV
THIS
A3 LESS ODJECTIOF4-
HIGH SALT OONTCNT.
AFTER THE WASHING AND DRAINING WERE COMPLETED) THE LEACHER WAS
TABLE
ANALYSIS OF SALT WASH WATER
TOTAL
SOLIDS
Soi.
Souas
((it
NONTAv:IN
((it
TANTuN
(dt
BOTTOM WASH
IST WASH
0.178
0.163
0.135
0.028
0.047
2ND WASH
0.150
0.146
0.116
0.030
0.036
STR0N
0.302
EXTRACT
Top WASH
WASH
0.638
0.631
0.483
0.148
0.221
2uo WASH
0.360
0.348
0.230
0.118
0.090
Isi
STRONG
EXTRT
0.035
f')
24
AN ISOLATED CIRCULATION
FILLED WITH STRONG EXTRACT FROM STORAGE.
SYSTEM WAS CONNECTED,
IN
WHICH THE CONTENTS OF THE STORAGE DARREL
THE EXTEACT
WERE CONTINUOUSLY EXCHANGED WITH
THAT GRADUALLY THE TEMPERATURE
EXTRACTJ
AND OF THE
WAS
STEAM
INTO THE HEATING COIL IN THE LEACHER AT THE SAME TIME, SO
WAS TURNED
ATURE
IN THE LEACHER.
WAS
THE DARK1 OF THE WATER IN THE DARK1
OF
DUILT UP
TO THE
THIS TEMPER-
LEACHING LEVEL.
MAINTAINED I3ETWECN 65 AND
THE INTERVAL E3ETWEEN CHANGE-OVERS AT FIRST WAS FIXED AT THE
MINIMUM TIME NECESSARY TO DUMP1 REFILL, WASH, AND HEAT
DUT LATER
A
THREE HOUR
A
FRESH LEACH,
INTERVAL WAS ESTADL1SHED.
ThE FRESH LEACH WAS ADDED TO THE SYSTEM RY CUTTING OFF THE
LIQUOR DEING PUMPED TO IT FROM STORAGE AND DIVERTING THE OVERFLJ
FROM THE
THE
THE HOT WATER GOING TO
HEAD LEACH INTO THE FRESH LEACH.
TAIL LEACH WAS SHIFTED DOWN THE LINE TO THE NEXT MOST EXHAUSTED
LEACH AND THE FORMER WAS DUMPED OR
As OFTEN AS REQUIRED,
ONE
CAST.tl
HUNDRED AND FIFTY POUND CATCHES OF
PUMPED TO THE EVAPORATOR FROM THE STORAGE SUMP.
STRONG EXTRACT WERE
STRONG EXTRACT FROM THE HEAD LEACH
WAS
BLED OFF AT VARIOUS
RATES FROM ONE POUND PER MINUTE TO THREE POUNDS PER MINUTE WITH THE
SMALLER QUANTITIES THAN THESE
LATTER BEING FIXED AS THE BETTER.
BROUGHT UP THE TOTAL SOLIDS CONTENT OF THE FINISHEC EXTRACT EUT THE
OVER-ALL YIELD
TABLE VII
WAS
IS
REDUCED.
A
TYPICAL CROSS-SECTION
SHOWING THE TOTAL SOLIDS CONTENT
ANY STAGE
OF
THE EXTRACTION.
OF
OF
THE LEACHING OPERATION
THE EXTRACT AT ANY ONE
INSTANT AT
25
TABLE
TOTAL
SOLIDS
jJ
FRESH BARK
VII
SOLUBLE
SOLIDS
NON-
____________
JQJ
TAN.
12.17
13.93
NACL
TAN.
ttl
____________
5.38
6.79
0.954
iST SALT WASH
0.683
0.631
0.438
0.148
0.221
2ND SALT WASH
0.360
0.348
0.230
0.118
0.090
0.353
0.350
0.179
0.171
0.0
2.62
l.
1.58
0.0346
TAIL LEACH No.
LEACH
I
o. 2
1.00
"
No. 3
1.62
"
No. 4
2.24
?
No.5
2.98
No. 6
3.39
No. 7
3.64
HEAD LEACH NO. 8
2.79
'I
ANALYSIS OF THE EFFLUENT FROM ThE TAIL LEACH IS INDICATIVE
THE
OF
LOSS SUSTAINED WHEN DUMPING.
THE DROP IN STRENGTH OF THE EFFLUENT FROM THE HEAD LEACH WAS DUE
TO THE DILUTION OF THE WATER
SALT WASH.
IT
IN THE
DARK AND RESIDUAL WATER FROM THE
ILLUSTRATED THE HANDICAP UNDER WHICH
A
TANNIN EXTRAC-
TION PLANT HAS TO OPERATE USING SALT-BEARING BARK.
FINISHED EXINACT FROM THE HEAD LEACH WAS
CLEAR LIQUID.
HOWEVER, AS
IT
COOLED,
A
A
DARK, REDDISH-DROWN,
BRICK-COLORED SEDIMENT APPEARED.
26
THIS SOLID APPARENTLY WAS THC FATS A:D
lION.
.\XCS ALSO REMOVED DY EXTRAC-
THE EXTRACT WAS QUICKLY ATTACKED BY YEASTS AND MOLDS, AND FOR
THIS REASON HAD TO
THE
KEPT
DE
IN COVERED, STERILIZED CONTAINERS.
LEACH EXTRACT WAS CONCENTRATED
DRY SOLIDS CONTENT,
VACUUM
IN THE
BC
EXERCISED
AS FOAMINC WAS GREAT.
THE HEAT TRANSFER AT
THE EVAPORATOR TO 25
EVAPORATOR
INCHES OF MERCURY, WHICH CORRESPONDED TO
CARE HAD TO
l
A
WAS
ov
MAINTAINED AT 2
TCMPEATURE
26° F.
OF AEOUT
IN KEEPING THE EVAPORATOR FROM COILING OVER
OTHER THAN THIS, NO DIFFICULTY WAS CNCOUNTEREO.
SOLIDS WAS QUITE LARGE AND JOT A LIMITING
FACTOR AT THAT STASE OF THE EVAPORATION.
THE CONCENTRATED LIQUOR
AS PUT INTO 6ARRELS
WITH
NO
ATTEMPT
DEING MADE TO SEPARATE THE SLUDGE, AND SHIPPED TO THE SPRAY DRIER FOR
THE FINAL PROCESSING
INTO POWDER.
THE SPRAY DRIER CONSISTED OF
A
DRYING CHAMDER INTO WHICH THE
HEATED AND ATOMIZED EXTRACT WAS SPRAYED AGAINST
THE WATER IN THE DROPLETS WAS
RESULTING POWDER WAS COLLECTED
F
I
IN A
A
BLAST OF HEATED AIR.
INSTANTLY VAPORIZED AND THE
MULTICLONE SUPPLEMENTED DY
A
BAG
LTER.
THE EXTRACT WAS HEATED WITH
A
STEAM COIL TO 1600 F. AHEAD OF THE
ATOMIZER.
TABLE VIII
GIVES THE TEMPERATURES USED
IN
THE EXPERIMENT.
27
TABLE
VIII
RUN No.
I
2
3
4
INLET TEMPERATURE
(° F.)
460
640
650
650
OUTLET TEMPERATURE
(° F.)
205
210
210
210
THE PRODUCT
AS
A
FINELY DIVIDED REDDISH-BROWN POWDER, FREE FROM
LUMPS ANO DECOMPOSITION.
THE MOISTURE CONTENT WAS 5.61
AT TH
DRIER.
THE BULK DENSITY WAS 21.1 POUNDS PER CUBIC FOOT, AND THE PARTICLE SIZE
AVERAGED 15-25 MICRONS.
AN EXTRACT FROM
I
oOMMET APPEARING
IN
ThE SPRAY DRYING REPORT
WAS AS FOLLOWS:
"STANDARD OPERATION OF DRYER WITH COOLING SYSTEM SET UP AT
IT WAS
MULTICLONE OUTLET.
NECESSARY TO PREHEAT THE MATERIAL
STEAM COIL AND USE AGITATOR WHILE HEATING.
ITH
COLLECTED MATERIAL AT
THE BOTTOM OF BBL. ALL DISSOLVES WITh THE ADDITION OF HEAT AND IS
EASILY PUMPABLE.
IN
ANO POWDER
LEFT
OPEN CONTAINER FOR ONE WEEK DOES NOT BECOME STICKY OR LUMP IN ANY
WAY.
THERE WAS CONSIDERAJLE DUSTING AT OUTLET OF COLD POWDER SYSTEM.
OPERATION
Asil
THE
PRODUCT ONLY SLIGHTLY HYGROSCOPIC
IS
VERY SATISFACTORY IN EVERY WAY.
DETERMINATIONS MADE ON SAMPLE
FOLLOWING VALtJES
OF
THE DRIED EXTRACT SHOWED
o
TABLE
IX
ASH
OVEN DRY
(v
01
94.35
4.91
SAMPLE No. 2
95.3
4.99
SAMPLE No. 3
94.6
9.94
SAMPLE No. 4
95.3
4.57
SAMPLE No.
SAMPLE
I
O. 3 WAS FROM THE ExTRACT PRODUCED BEFORE THE TOP WASH-
ING PROCEDURE WAS ADOPTED.
A 5
IN
SOLtJT$ON OF THE CRIED PRODUCT WAS MADE UP WITH WARM WATER
ORDER TO DISSOLVE ALL OF THE POWDER.
DIVIDED, ONE-HALF BEING CENTRIFUGED.
LIQUOR OF THE LATTER AND A SAMPLE
OF
U')N
COOLING
THE SAMPLE WAS
A QUANTITY OF THE SUPERNATANT
THE FORMER WERE ANALYZED WITH THE
RESULTS LISTED BELOW.
TABLE
UNCLARIFICO SAMPLE
9l.6
TOTAL SOLIDS
68.32
SOLUELE SOLIDS
29.3
CORRECTED NONTANN INS
39.O
TANNIN
(CONTD.)
29
(TA9L
coNT,NuD:)
X
CLARIFIED SAMPLE:
55.8%
ToTAL SoLlos
55.3%
Sou.aLE Stios
24.5, CoRcTto
T*u
30.8%
IN THE SOLUBLE PORTION OF
A SUaSTANTIAL PART OF THE TANNIN WAS
THE EXTRACTE BUT
IT
WAS APPARENT
NOPJTANNIIS
THAT THE TANNIN HELD IN THE SLUDGE
MUST BE RECOVERED.
WHEN A
UNDER
A
AS
VACUUM AND REDISSOLVED, THERE
CIPITATE.
NO
WAS
EVAPORATED TO DRYNESS
EVIDENCE 0F
A
StCOND PRE-
THE CONCLUSION WAS THAT THE EXTRACT WOULD BE SATISFACTORY
IF THE SLUDGE IN
IN
CLARIFIED LIU0R
SAMPLE OF THE
TABLE
MONTHS RUN ARE
THE
ORIGINAL EXTRACT
(SEE PAGE
LISTED.
30)
WERE REMOVED.
ThE YIELDS OBTAINED OVER THE FIRST ThO
THESE FIGURES ARE SUMMARIZED
TA?LE
SuRv
OF
XI
TABLE Xl
6.82 %
TANNIN IN ORIGINAL BARK
TANNIN RECOVERED
(B*Ri<
IN TABLE
BASIS)
3.43
TANuIN AVAILABLE RECOVERED
50.25
TANNIN AVAILABLE LOST IN SALT WASH
¡3.53
TANNIN AVAILABLE LOST IN TAIL LEACH
11.56
(CorTo.)
XII
:
TABLE
TANN N N
iST WASH
I
TANt4 N
I
2ND WASH
(LBS.)
N
TAr
XI
t
N
I
N
TA NN N
I
I
N
TANN
N
EXTRACT
I
£J
I
TANN$ N AcCOUNTED FOR
(Los.)
BARK
TANNIN
DAit
(LBS.)
(LBS.)
(Los.)
I-21
542.8
37.46
0.39
0.39
3.42
8.68
15.39
28.27
l-22
414.0
28.57
2.78
.94
3.58
6.62
I3.J5
27.97
l-23
474.6
32.75
3.22
2.22
3.67
7.59
18.00
34.70
l-24
489.9
33.80
4.12
2.61
3.25
7.84
¡8.37
36.19
l-25
508.4
34.52
3.40
2.20
4.53
8i3
¡8.36
36.62
l-26
459.0
31.17
2.71
2.14
3.72
7.34
¡7.88
33.79
l-27
482.8
32.78
3.38
2.16
3.36
7.72
18.24
34.86
l-28
512.1
34.77
2.91
2.29
3.14
8.19
18.05
34.58
I-29
489.2
33.22
2.99
2.78
3.39
7.33
¡5.39
32.38
k30
507.6
34.47
2.21
¡.57
4.14
8.12
¡6.42
32.46
I-31
506.4
34.38
2.43
¡.68
4.73
8.10
17.63
34.57
2-I
514.1
34.91
2.09
1.37
4.79
8.23
¡5.90
32.38
2-2
571.7
33.82
2.37
2.42
4.88
9.15
¡8.50
37.32
2-3
484.4
32.89
2.19
1.44
4.28
7.75
¡7.25
32.91
TAIL LEACH
SPENT BARK
(Los.)
(ts.)
(LBS.)
C,)
o
TOTALS 6,957.0
474.50
37.19
27.21
54.88
111.29
238.43
469.00
1I
JJ CONTINUED:)
(TABLE
TANrJsrI
REMAINING u
23.45
SPENT [ARK
TANNIN UNACCOUNTED
TOTAL SOLIDS
TANNIN U
ar
EXTRACT
BUT THAT THE LOSSES MADE
THE
TANNERS
2.62
%
IT APPEARS THAT THE EXTRACTION
THE PROCESS UNECONOMICAL.
FINISHED EXTRACT, CÇ)TAININC
RATED OUT SEFORE
%
1.58
EXTRACT
FROM THESE RESULTS
1.16
NWANTEO
ALSO, SLUDGE
MATERIAL,
THE PRODUCT WAS CONSIDERED
FEASIDLE
WAS
HAD TO BE
IN
SEPA-
SATISFACTORY FROM THE
VIEWPOINT.
2.
BATCH COUNTERCURRENT
XTRACT ION WITH WET
BAR1K
OOVIOUSLY, THE YIELD FROM THE OPERATION OF THE LEACHERY IN CONTINUOUS EXTRACTION WAS TOO LOW AND THE EXTRACT PROM THE HEAD LEACH WAS
LOW
IN TOTAL SOLIDS CONTENT.
THEREFORE, THE PROCESS WAS CHANGED TO
DATCH OPERATION AND PATTERNED AFTER
ÍORNIA, IN
THE MANUFACTURE OF
THE
ONE
IN USE AT ARCATA,
EXTRACT FROM TANE;ARK OA<.
IT
CALI-
WAS
BE-
L1EVED THAT BOTH OF THE DRAWBACKS LISTED AEJOVE COULD 6E OVERCOME AT
THE
SAME TIME BY
THE SA
THIS CHANGE.
LEACH BARRELS WERE RETAINED tUT,
ARRANGEMENT, WERE SET ON
A
LEVEL
IN
INSTEAD OF
INDIVIDUAL CRADLES THAT
A
RAMP
WERE
A
32
HINGED SO THAT EACH DARREL COULD
E
TIPPED FORWARD TO
A
HORIZONTAL
BARK DISPOSAL WAS FACILITATED BY RAISING THE
POSITION FOR DUMPING.
FOUNDATION FOR THE BATTERY HIGH ENOUGH TO ALLOW
PLACED UNDER THE LIP OF THE BARREL WHEN
IN
A
WHEELBARROW TO 6E
THE DUMPING POSITION.
THE SPACE BETWEEN THE FALSE AND TRUE BOTTOMS OF THE BARREL WAS
TAPPED AND, DY MEANS OF
A
SHORT LENGTH OF HOSE AND
BARREL WAS CONNECTED TO
A
HEADER LEADING TO
DISCHARGED THROUGH
OF THE BARRELS.
A
A
VALVE, EACH
A
GEAR PUMP.
SINGLE-PASS HEAT EXCHANGER AND
A
THE PUMP
HOSE TO ANY ONE
FACILITIES FOR PUTTING WATER THROUGH THE HEATER FOR
FILLING THE TAIL LEACH WERE ALSO PROVIDED.
A
TRAY DRIER WAS
INSTALLED FOR DRYING THE GROUND AND WASHED
THE HOT AIR FOR THE DRIER WAS OBTAINED DY TAPPING THE FORCED
OARI(.
DRAFT FAN ON ONE OF THE FURNACE INSTALLATIONS IN NE POWERHOUSE NEAR13V.
A
PORTABLE BARK WASHER
WAS
MANUFACTURED FROM
CEMENT CART OF ABOUT FIFTY GALLONS LIQUID CAPACITY.
FITTED WITH
A
SCREEN-COVERED FALSE BOTTOMS
A
A
TWO-WHEELED
THE CART WAS
DUMP VALVE, AND
A
PUMP
FOR EMPTYING.
¡N
ALL OTHER RESPECTS THE PILOT PLANT WAS IDENTICAL
TO THE ONE
FORMERLY USED.
THE BARK OF THIS SERIES
OF
OPERATIONS WAS HOGGED AND GROUND IN
THE SAME MANNER AS PREVIOUSLY DESCRIBED.
THE WASHING PROCEDURE, HOWEVER, WAS CONSIDERABLY ALTERED.
WEIGHED BARK, INSTEAD OF BEING PLACED
IN
THE
THE LEACHER FOR WASHING, WAS
LOADED INTO THE WASH CART AND FLOODED WITH WATER RECOVERED FROM THE
33
SECOND WASH OF
A
PREVIOUS CHARGE.
AFTER
A
FIVE-MiNUTE SOAK, THE
WATER WAS DRAINED AWAY ANO THE BARK AGAIN WAS FLOODED.
THIS SECOND
WASH WATER WAS FRESH AND, AFTER ANOTHER FIVE-MINUTE SOAKS WAS PUMPED
TO STORAGE FOR USE AS THE FIRST WASH OF A SULSEQUENT CHARGE.
THIS NEW PROCEDURE DROUGHT ABOUT
A
68
SAVING
MOST AS COMPLETE SALT REMOVAL AS FORMERLY, AND
MATELY 3%
OF THE
A
AVAILABLE TANNIN IN THE BARK.
WAS SAVED IN THE LEACHING OPERATION IN THAT
THE LINE FOR WASHING AS
WS
A
IN
WATER, AN AL-
SAVING OF APPROXIN
ADDITION,
SOME
TItJE
LEACHER WAS NOT OUT OF
THE CASE FORMERLY.
THE COUNTERCURRENT PRINCIPLE WAS RETAINED IM THE NEW OPERATION,
BUT THE TRANSFER OF EXTRACT FROM BARREL TO DARPEL WAS DONC AT SPECI-
FlEO INTERVALS INSTEAD OF CONTINUOUSLY.
A
TYPICAL FOUR-HOUR CYCLE IS
OUTLINED AS FOLLOWS:
A PREVIOUSLY DUMPED LEACHER WAS FILLED WITH WASHED OARK.
PRESCRIBED TIME,
A
A
VALVE TO THE PUMP WAS OPENED AT THE HEAD LEACH, AND
WEIGHED QUANTITY OF STRONG EXTRACT WAS PUMPED TO STORAGE.
MAINDER
OF [iARK.
AS
AT THE
PUMPED FROM THE HEAD LEACH
ThE RE-
INTO THE FRESHLY PILLEO BARREL
THEN, THE EXTRACT FROM THE NEXT STRONGEST LEACH WAS PtJMPED
INTO THE HEAD LEACH.
THE BARREL THUS EMPTIED WAS
THE ONE NEXT TO IT, AND SO ON
IN TURN
FILLED FROM
HOT WATER
UNTIL THE TAIL LEACH WAS DRY.
WAS USED TO REPLACE THE EXTRACT PUMPED FROM THIS ONE,
RETURNING TO THE HEAD LEACH, PART OF
TO THE FRESH LEACH UNTIL IT WAS FULL.
ITS CONTENTS WAS PUMPED IN-
ThE QUANTITY THUS REMOVED FROM
THE HEAD LEACH WAS REPLACED UY SOME OF THE EXTRACT FROM THE
STRONGEST LEACH.
EACH BARREL
WAS
NEXT
IN TURN FILLED FROM THE ONE
CONTAINING THE NEXT CTRONGCST LIQUOR.
AT ThE END OF THIS PUMP-OVER THE DRAINED TAIL LEACH WAS CAST
AND REFILLED WITh FRESH1 WASHED LARK TO AWAIT ITS TIME TO BE PUT
ON
THE LINE.
SIMULTANEOUSLY, THE LIQUOR DURING THE PUMP-OVER WAS HEATED TO
THE CORRECT LEACHING TEMPERATURE BY ADMITTING STEAM TO THE HEATER.
Tf
COMPLETE FLcJSHECT FOR
THIs SETUP IT OUTLINED
THE FIRST RUN WITH THC MEW PILOT PLANT ARRA
USiNG
A
CROSS-SECTION
CURVE fo. 2
LINE
Th
ETET
WAS MADE
LEACHER CHARGE OF 175 LBS. OF WET SARK AND A CRAW-OFF OF 125
TRANSFER WAS MADE EVERY FOUR HOURS.
LOS. OF STRONG EXTRACT.
A
PLATE D.
ON
(sEE PAGE
ß?1
OF
THE EXTRACTION IS
ILLUSTRATED BY LINE
'TAr'
IN
SECOND RUN1
IN
36).
REPRESENTS
ICH ALL OF THE EXTRACT
SI1ILAR CROSS-SECTION OF
A
IN THE HEAD LEACH WAS
A
REMOVED AT THE FOUR-
HOUR INTERVAL.
THE DROP
IN
EXTRACT CONCENTRATION INDICATED
ON
THE CURVE WAS
THOUGHT TO 6E DUE CHIEFLY TO THE WATER IN THE BARK AND PARTLY BECAUSE
OF NONEQUILIBRIUM IN THE HEAD LEACH.
YIELDS OBTAINED IN THESE
RESPECTIVELY OF TABLE
jI
TWO
RUNS APPEAR
IN COLUMNS
I
AND 2
(SEE PAGE 3?).
THE PER CENT RECOVERY WAS VERY
LOW
AND ORVIOUSLY
UNSATISFACTORY.
LOSSES IN THE SALT WASH WERE ESTIMATED, CECAUSE THE FRESH BARK
;or
WAS
ANALYZED BEFORE WASHING.
AN INCREASED WATER-TO-EARI< RATIO WAS TRIED IN THE THIRD RUN.
125 LOS. OF WET BARK WERE CHARGED TO EACH LEACHER AND A COMPLETE
wìt, 3ccônd wai,
F1r5# i.sh e'nd
of
pvioubc*ck
b,'l11
*rc'
3ccö,,d Wa'/7
Mide
Lva*(r.
MATCH EXTRACT/oN
Ps/i ¿-1zo
Raw b.rkj
tvcçt'r
/.,_1
t,
Je w e r
ç
r
r--
r
Pwwp
rae 1
'rom
I,ad
/g4
o47/ Sc/d5
r
I
i
Hft
h
4
J
e
(Ja'
PL4TE
1
TAOL
RUN No.;
I
-
(\
j',1
TA N
TS
JQJ
td't
/&/
fcct\
4
3
2
¡
XIII
TAN
Id
J
TS
('1
.foj
TA N
TS
?\
(d\
¶/,j
/OJ
6
s
TA N
!cif\
TS
7
'iI
TS
te"
tI
TA N
VJ
f'\
\)J
(\
TA
-
TS
TA N
fe'
jb
ORIG. BARK
11.92
5.46
¡4.82
6.28
11.08
5.74
¡3.50
6.52
¡2.33
4.86
13.70
6.02
12.42
5.10
RCCOVERED3
3.74
2.11
3.53
¡.73
5.46
3.39
6.3'
3.59
5.C(
2.75
5.92
3.08
4.87
2.40
AVA LAOLE)
RECOVERED)
I
LOST IN
31.4
38.7
23.6
27.6
49.3
59.1
14.0
10.0
14.0
10.0
14.3
45.7
34.0
46.3
36.6
8.9
17.3
¡6.0
25.8
46.9
53.4
47.6
56.6
43.2
51.2
32.9
41.0
10.13
¡4.3
11.6
¡7.13 ¡1.6
¡3.0
7.5
15.0
8.3
32.4
27.7
28.9
23.0
32.2
28.2
38.6
.9
39.1
33.9
4.0
3.1
9.9
12.0
3.6
5.2
8.4
6.9
10.8
)
S*1y WASH)
Losi 1N
)
TAu. LEACH)
tJNACOOUNTED
I
2
TOTAL SOLIDS.
TANNIN.
OVEN DRY BARK BASIS.
3.07
U
TAKE-3FF FROM ThE
HE:AD
LEACH, AvERAGING 230 LBS,, WAS MADE.
As AN AID TO TUE ESTAI3LISHMENT OF EQUILIBRIUM IN THE HEAD LEACH,
THE TIME CYCLE WAS LENGTHENED TO FIVE HOURS AND1 AS SON AS THE PUMP-
OVER WAS COMPLETED, THE CONTENTS 0F THE HEAD LEACH WERE CONTINUOUSLY
RECIRCULATED.
Liuc
D" 0F CURVE No. 2 SHOWS THE SOLIDS PICKUP FOR AN
AVERAGE OF THE TWO RUNS WHOSE RESULTS ARC LISTED IN COLUMNS 3 ANO 4
OF TABLE Xi
¡
I.
THE NEXT
E3ARK
ATTPT
IMPROVEMENT WAS TO DECREASE THE WATER-TO-
AT
RATIO DY USING ¡50 LBS. 0F 3ARK PER LEACH
PLETE STRONG LIQUOR WITICRA\?AL.
OF TADLE XIII, AND
COLUMN
UT RETAINING THE COM-
RESULTS OF THIS TRIAL APPEAR
IN
CROSS-SECTION OF THE LEACH ANALYSIS
A
IS
REPRESENTED EY LINE "O" OF CURVE No. 2.
FURTHER REDUCTIONS
WET
F;ARI<
BARK-TO-WATER RATIO IN WHICH ¡CO LBS. OF
IN
WERE CHARGED PER LEACH WITH TOTAL WITHDRAWAL ARC LISTED IN
COLUMNS 6 AND 7 OF TABLE XII
A
I.
SUMMARY OF ALL OF THESE RUNS ON THE OASIS OF POUNDS OF EXTRACT
WITHDRAWN PER POUNDS OF DRY BARK PER LEACHER
IS
PRESENTED EELOW.
TABLE
RUN
£&:.
WATER-TOBARK
RAT1O
HOU
PER
TAN.
IN
EXTRACT
%
TANNIN
ROOVERED
TAw1IN
INTAILINQ
4
0.936
27.6
36.6
I
¡.83
¡.96
4
¡.08
38.7
34.0
6
2.63
5
1.167
E1.2
32.9
2
(CoTD.)
39
øONTtNUED)
RuN
WATER-TOBARK
RATIO
HouRs
PER
% Tr4.
% TAwNIN
IN
CYCLE
EXTRACT
RECOVERED
ni
TANNIN
TAILINGS
7
2.64
5
0.958
47.0
33.9
5
2.75
5
0.976
56.6
28.2
4
3.74
5
0.93
53.4
23.3
3
4.24
5
0.797
59.1
27.7
ANALYSIS OF THE TABLE INOICATCS THAT THE WATER-TO-BARK RATIO WAS
DIRECTLY PROPORTIONAL TO THE RECOVERY EFFICIENCY ANO INDIRECTLY PROPORTIONAL TO THE TANNIN CONTENT 0F THE LEACH LIQUOR.
THE LOWEST LOSSES
OF THROWING
A
IN THE
HEAVIER LOAD
ON
TAILINGS WERE SUSTAINED AT THE EXPENSE
THE EVAPORATOR.
IF
THESE LOSSES ARE TO
BE FURTHER REDUCED TO THE POINT WHERE THE PROCESS CAN BE OPERATED
ECONOMICALLY,
A
STILL GREATER BURDEN MUST 0E PLACED ON STEAM CONSUMP-
TI ON.
LOSSES IN THE SALT WASH APPEAR TO BE AT THEIR IRREDUCIBLE rAINIMUM OF IO
OF THE AVAILABLE
ENTLY THIS PARTICULAR
OF
A
TAPININ CONTENT OF THE FRESH BARK,
LOSS MUST
3E
APPAR-
RECOGNIZED AS PART OF THE OVERHEAD
SALT WATER OPERATION.
DURING THESE RUNS THE
TIMES TO AS HIGH AS 90
C.
TEMPERATURE OF LEACHING WAS ELEVATED AT
BUT AVERAGED
EXTRACT HAD CONSIDERABLE SOLUBLE
UPON COOLING.
A STEP WAS
750
c
UTCRIAL IN IT
THE RESULTING
WHICH PRECIPITATED
ADDED TO THE PROCESS1 AFTER EVAPORATION
OF
40
THE EXTRACT TO M3OIJT I5
TOTAL SOL$C5, CONSISTING OF THE COOLING AND
SEDIMENTATION OF THE EXTRACT.
THE SUPERNATANT LIQUOR WAS DRAWN OFF
AND CONCENTRATED FURTHER TO FORM THE FINISHED PRODUCT.
THE HIGHLY CONCENTRATED
PREVIOUS CASE, NO DIFFICULTY
EXTRACT WAS SPRAY DRIED.
JAS
As IN ThE
EXPERIENCED.
ANALYSIS OF THE DRIED POWDER YIELDED THE FOLLOWING RESULTS
TABLE
XV
TEST
_L_
620
(o fÇ)
TEST
TEST
2
3
400
400
TOTAL SOLIDS
(%
99.8
100.5
100.0
SOLUBLE SOLIDS
(%)
96.4
98.9
97.3
TANNIN
(%)
46.1
45.8
34.8
NACL
(%)
PURITY
(TAN/SS
x
lOO)
MOISTURE
VOLUME OF SLUDGE
(IO
Soue.)
NONTANNIN
3.17
3.16
2.42
(%)
47.8
46.3
36.9
(%)
5.0
5.2
5.8
(%)
8
(%)
50.3
12
53.1
18.4
62.5
THESE ANALYSES SHOW A DECIDED IMPROVEMENT OVER ThE FIRST DRIED
SAMPLES (SEE TABLE j
A
ON PAGE 28),
HIGHER TANNiN CONTENT.
SLUDGE
IN
THE POWDER WAS MORE SOLUBLE AND HAD
THE REDISSOLVED POWDER WAS STILL
41
APPAEWT FUT WAS
OT
GREAT
IN AS
PROPORTION AS
A
EXTRACT THAT WAS
IN
NOT CLARIFIED IN THE EVAPORATION STAGE.
BATCH COUNTERCURRENT EXTRACTION UsIw
2A.
DRY BARK
INVESTIGATION WAS THE DRYING OF
THE NEXT ANO FINAL STEP IN THE
TO THE LEACHERS, WITH
THE WASHED EARK BEFORE CHARGING
CREASING THE SOLIOS CONTENT 0F THE FINISHED EXTRACT.
A
VIEW OF
IN-
LEAcHING OF THE
WET DARK IN BOTH PREVIOUS RUNS RESULTED IN LARGE QUANTITIES OF DILUTE
EXTRACT WHICH WOULD REQUIRE
ANO HIGH OPERATING COSTS
Ii
A
IS
A
FACT THAT
MODERN EVAPORATOR THAN
LARGE EXPENSIVE EVAPORATOR
A
COMMERCIAL SCALE.
ON A
A
WILL EVAPORATE MORE WATER
POUND OF STEAM
IT
WILL
TRAY DRIER.
IN A
WERE LARGE QUANTITIES OF HOT FLUE OASES AVAILADLE,
OLE,
IN
IN
HOWEVER, WHERE THERE
IT WAS
THOUGHT FEASt-
ANY PROJECTED PLANT, TO UTILIZE THE HEAT FOR DRYING PURPOSES.
ACCORDINGLY,
ROUNDING
INSTALLATION
A
3ft AND HAD
A
TRAY DRIER WAS
A
SHELL SUR-
EACH TRAY MEA5URED ACOUT 30"
STACK OF 12 TRAYS0
A
UILT CONS$STING OF
SCREENED BOTTOM.
x
48"
x
THE DRIER WAS SO CONSTRUCTED IN DEPTH
THAT EACH TRAY COULD BE OFFSET FROM THE ONE ABOVE AND BELOW, THUS MAKING
A
PATH FOR
THE HOT AIR TO PROGRESS UP FROM THE OOTTOM OF THE DRIER TO
THE TOP AND SWEEP ACROSS THE CARK
1-IEATED
IN
EACH
AIR UNDER A PRESSURE OF 0.2
FORCED DRAFT FAN ON ONE OF THE FURNACES
TO THE BOTTOM OF THE DRIER.
A
LINE
INDIVIDUAL TRAY.
INCHES OF MERCURY FROM THE
IN
TO THE
MOVED THE WET AIR FROM THE DRIER UNDER
A
THE POWERHOUSE WAS PIPED
INTAKE OF THE SAME FAN RE-
VACUUM OF 0.3 IuciEs OF
42
MERCURY.
LOUVERS AT THE E3OTTOM OF THE DRICR WERE OPENED OR CLOSED TO
ADMIT COLD AIRS AS DESIRED, TO MAINTAtN THE TEMPERATURE AT THE BOTTOM
OF THE DRIER NEAR
IT
FOR
A
103-105° C.
PROVED POSSIBLE TO DRY MORE THAN SUFFICIENT BARK TO 9O
0.D,
CHARGE EVERY FOUR HOURS.
THE LEACHING PROCEOURE WAS IDCNTtCAL TO THAT PREVIOUSLY USED ON
WET BARK.
THE OPERATION WAS ON A FOUR-HOUR CYCLE WITH
CHARGE OF 85 LOS. OF BARK.
75 LBS. or EXTRACT
BEING REMOVED FROM
A
THE WITHDRAWAL WAS
INCREASED TO ¡25 LBS. OF EXTRACT.
LINES
TFIE
GROSS-SECTION OF THE LEACHING OPERATION
"A"
AND
TABLE
"E3"
THE
IN
IS
SECOO TRIAL
ILLUSTRATED BY
IN CURVE No. 3.
IS
A
SUMMARY OF THE RESULTS OF THE FIRST RUN AT 75 LBS.
THE SECOND RUN AT ¡25 LOS. DID NOT GIVE RELIABLE DATA.
WITHDRAWAL.
THE TANNIN IN THE ORIGINAL BARK WAS ON THE OASIS OF WASHED DARK.
TABLE
XVI
WATER-TO-BARK RATIO
1.13
TOTAL
SOLIDS
?\
/I
ORIGINAL BARK
RECOVERED
(BARK BASIS)
AVA LAE3LE RECOVERED
I
I
TANNIN
TOTAL
SOLIOS
,of\
/'-J
10.97
5.49
¡2.79
4*49
2.03
6.13
40.9
(CONTO.)
37.0
47 8
.47
TANNIN
jQ
5.57
(TARLE
j_
CONI INUED:)
WATER-To-BARK RATIO
¡
TOTAL
SoLlos
13
I
TANlJIN
TOTAL
SoLlos
(cl
Iç
Los'r
IN
TAILINGS
UNACCOUNTED
EXTRACT ANALYSIS
37.8
28.4
21.3
34.6
4.52
1.93
53.7
3.84
47
TANT4IN
45
SMRY
OF PI LOT PLANT OFEPAT I ON
IN SUMMARIZING THE RESULTS 0F THE OPERATION OF THE PILOT
EXTRACTION PLANT, THESE FACTS ARE
(I)
THE RESIDUAL TANNIN
ECONOMICAL OPERATION.
WHICH HAVE BEEN
J
PRQOAELY
IMVEtDIATELV APPARENT
THE SPENT BARK
IS
THERE ARE MANY CELLS
TOO GREAT FOR
IN
THE BARK
LEFT SEALED IN ThE GRINDING OPERATION AND ARE UN-
AFFECTED 6V LEACHING.
THIS PROBLEM
CAN BE ATTACKED
IN IWO WAYS.
ONE WOULD 0E TO
MODIFY THE GRINDING OPERATION TO EFFECT GREATER REFINEMENT OF THE
THE SECOND WOULD BC TO MODIrY
BARK.
CREASING THE
THE
EXTRACTION PROCEDURE DY
IN-
ATCR-TO-BARK RATIO, DY ADDING INDIVIDUAL CIRCULATION
PUMPS AND HEATERS TO THE LEACH TANKS, ANb
13V
INCREASING THE TIME
INTERVAL BETWEEN PtJMP-OVE3, AUDI POSSIBLY, EV ItiCREASINC
OF LEACH TANKS.
THE NUMBER
THESE LAST TWO HAVE ONLY LIMITED POSSIBILITIES
BECAUSE THE LARGE VOLUME
OF
RAW
MATERIAL TO BE HANDLED PER DAY WOULD
MAKE THE PLANT TOO LARGE.
( 2)
60
TO
THE TEMPERATURE OF
650 C.
IN
PER CENT TANNIN
LEACHING MUST 0E MAINTAINED AT ABOUT
ORDER TO KEEP TI-lt RATIO OF PER CENT TOTAL SOLIOS TO
IN THE FINISHED EXTRACT AS
TEMPERATURES WOULD THROW TOO GREAT
AS
WELL
AS
(3)
AND
A
LOW
AS
POSSIBLE.
HIGHER
LOAD ON THE CLARIFYING EQUIPMENT
ADVERSELY AFFECT THE COLOR AND QUALITY OF THE EXTRACT.
CARE MUST BE EMPLOYED AT ALL TIMES TO MINIMIZE FERMENTATION
MOLDING OF THE EXTRACT GY KEEPING ALL VESSELS STERILIZED AND
COVERED.
THE SUGAR CONTENT OF THE EXTRACT PROVIDES AN EXCEL.LENT
CULTURE MEDIUM FOR TANNIN-DESTROYING MOLDS AND YEASTS.
(4)
THE LOSS DURING SALT WASHING IS CONSIDERABLE.
IF
SOME
OTHER WAY COULD 6E DEVELOPED TO REMOVE THE SALT WHICH WOULD NOT ALSO
REMOVE THE TANNIN, SO1E OF THE MOST SOLUBLE AND DESIRABLE TAMI1
WOULD BE RECOVERED.
(5)
DRYING BARK BEFORE EXTRACTION TO DRING UP THE SOLIDS
CONTENT CF THE EXTRACT SEEMS, ON THE FACE OF IT, TO BE TOO INVOLVED
AND EXPENSIVE
(G)
A
TO WARRANT SUCH A
PROCEDURE.
CHOICE OF OPERATIONAL METHOD MUST DE MADE BETWEEN
CONTINUOUS AND BATCH SYSTEMS.
ON THE BASIS OF PILOT PLANT RESULTS,
GAVE THE BEST PERFORMANCE.
THE CONTINUOUS
SYSTEM
COMPARISON OF THE OPERATIONAL EFFICIENCY
OF EACH SYSTEM CAN 3E MAtIE WITH THE AID 0E TABLE
TABLE
VlI.
XVII
CoT I NU0US
(ì__
AVAILABLE TANNIN RECOVERED
n
ti
n
it
It
I
TOTAL SOLIDS
IN
IN
SPENT BARt<
UNACCOUNTED
TAILINGS EXTRACT
EXTRACT
TANNIN IN EXTRACT
(% PURITY)
BATCH
(1
50.25
59.1
23.45
27.7
1.16
3.1
11.56
NONE
2.62
60.3
1.52
52.0
THE CATCH PROCESS GAVE
CONTAINED
PROCESS
IN
A
SOMEWHAT
BETTER RECOVERY
THE TAIL LEACH EXTRACT WAS DISREGARDED.
THIS EXTRACT
WAS
IF
THE
IN THE
TANNIN
CATCH
ALL PUMPED TO THE NEXT LEACHER, WHILE IN THE
CONTINUOUS PROCESS ONLY THE QUANTITY ABOVE THE LEVEL LIMITING THE
SYPHON ACTION WAS SAVED.
1F'
ALL OF THIS LIQUOR HAD BEEN PASSEC
ON TO
THE NEXT LEACH 1N PLACE OF THE SAME QUANTITY OF FRESH WATER, THE REOF THE AVAILABLE TANNIN.
Ii56%
COVER? WOULD HAVE BEEN INcREASED DY
THE OVER-ALL RECOVERY OF TANNIN WOULO THEN HAVE BECOME INCREASED BY
2
OF
THE AVAILABLE TANNIN.
ADDITIONS THE RESIDUAL TANNIN
IN
THE CONTINUOUS THAN
IN
IN
THE SPENT BARK WAS LESS IN
THE BATCH OPEBATION.
THE TANNIN CONTENT OF THE EXTRACT FROM THE LEACHERS IN THE CON-
TINUOUS OPERATION WAS HIGHER THAN THAT
OF'
THE BATCH, WHILE THE RATIO
or PER CENT TOTAL SOLIDS TO PER CENT TANNIN WAS
CONDITION WAS, IN ALL PROCABIL3TY
A
LEP.
THIS LATTER
RESULT OF LOWER EXTRACTION DtMPER-
ATURES ANO NOT TOO SIGNIFICANT.
ALL
OF
THE SEEMING ADVANTAGES
r
THE CONTINUOUS SYSTEM MUST,
HOWEVER, BE BALANCED AGAINST THE SIMPLER OPERATION OF THE 3ATCH PROCESS.
48
HEMLOCK EX1BACT AS
A
TAritNG AGENT
SAMPLES OF THE CONCENTRATED EXTRACT AND OF THE POWDERED EXTRACT
WERE SUBMITTED TO SEVERAL TANNERS FOR TRIAL TANNING.
THEIR EXPERIENCES DORE OUT SMOOT AND FREY (4),
CLAIMED GOOD
THE LEATHER PRODUCED WAS
RESULTS FROM TANNING WITH HEMLOCK EXTRACT.
OF GOOD QUALITY AND FIRMNESS GUT POSSESSED
wo
A
REDDISH CAST.
IN
SOME
CASES SLIGHT DEPOSITS OF DARK RESIDUES WERE VISIDLE.
THE O4E UNFAVORABLE FEATURE WAS
MATERIAL TO WHICH THE TANNERS OBJECTED
NUISANCE
IN
INSOLUBLE
THE LARGE VOLUME OF
OU
THE GROUNDS THAT
IT WAS A
THE VATS AND TENDED TO PLUG THE PORES OF THE HIDES.
THE EXTRACT
IN
ALL CASES WAS USED IN
CHIEFLY QUEBRACHO AND CHESTNUT.
A
MIXTURE OF OTHER EXTRACTS,
HEMLOCK EXTRACT CONTAINS CONSIDERArLE
IMPURITIES SUCH AS HEMICELLULOSES AND OTHER POLYOSES WHICH FtRMENT TO
FORM ACETIC, LACTIC, AND OTHER ACIDS, ALL OF WHICH HAVE
EFFECT ON TH
THICKENING OF THE HIDES.
A
BENEFICIAL
BECAUSE OF THIS FEATURE, SOME
HEMLOCK EXTRACT IN THE TANNAGE IS DESIRABLE, ESPECIALLY WHEN SUCH HIGH
QUALITY LEATHERS, AS BELTING AND SOLE LEATHER, ARE BEING MADE.
TIERE
IS
A
POSSIBILITY THAT WHEN CONDITIONS
IN THE
LEACHER HAVE
BEEN IMPROVED BY LOWERING THE TEMPERATURE OF EXTRACTION TO THE POINT
WHERE THE COLORING MATTER 00ES NOT GO INTO SOLUTION AS READILY,
LIGHTER-COLORED LEATHERS CAN
BE
PRODUCED.
49
11E-CONSTRUCT I ON COST EST I MATES
IN ORDER TO DETERMINE WHETHER COMMERCIAL SCALE OPERATION
WOULD PROVIDE
A
WORTH-WHILE
INVESTMEMT, THE OPTIMUM OPERATING
CONDITIONS U! THE PILOT PLANT WERE TRANSPOSED TO
OF HANDLING THE TOTAL OUTPUT OF WASTE
EIGHTY-SIX
TONS WET
HARt<
A
PLANT CAPAE3LE
OF ONE HU!DREO AND
WEIGHT,
PRESENT QUOTATIONS ON HEMLOC< TANNIN ARE FIFTEEN CENTS PER
POUND F,O.3, PLANT,
THIS FI3URE
APPLIED TO
NET YIELD OF 3.O4
A
OF THE DRY DARK AS TANNIN, SHOWS A DAILY CROSS
INCOME OF
3&'4.33
TO ElE POSSI6LE.
¡N
COMPILING THIS ESTI;TE, FREQUENT REFERENCES WERE MADE TO
CHAPTER
(
6).
,
CHEMICAL ENGINEERING PLANT DgßIGN,
OBvIoUsLY, ANY DATA FOM THIS
FROM MANUFACTURCRSt ESTiMATES,
PAST,
IS
E300K,
DY F.
C. VIL6RANDT
FROM COMPANY FILES, OR
ARE SUQUECT TO WAR INFLUENCE
IN ThE
PRESENT, AND FUTURE, AND ARE THUS LESS RELIACLE THAN USUALLY
ThE CASE WITH SUCH ESTIMATES.
TABLE
I
PRESENTS RAW MATERIALS COSTS WHICH APPROXIMATE
THOSE OF THE PROJECTED PLANT.
k
ADDITION,
TE
TEMPERATURES
N
THE
WATER ARE iNCLUDED.
TABLE
(SEE PAGES 51
AND 52) CONTAINS THE TYPE, CAPACITY,
COST, AND INSTALLATION CHARGES, OF THE EZUIPMENT NECESSARY TO
OPERATE THE PLANT ACCORDING TO THE FLOW SHEET
THE CALCULATIONS THAT WERE MADE
IN
ON
PAGE
IO.
DETERMINING EVAPORATOR
OPERATING CONDITIONS, HEAT EXCHANGER DIMENSIONS, PUMP SIZES, STEAM
50
TAULE
Viii
RAW MATER IALS COSTS AND WATER TEMPERA TURES
(I)
Cosr or SrEAM PER 1000 LoSø
(2)
CosT or ELECTRICITY PER HORSEPOWER
(3)
CosT or FILTEI1ED WATER PER
(4)
COST OF RîGET
(5)
CosT or OAG AND CLOSURE
(6)
AVERAGE YARLY TCMPCrATURE or FILTERED
(7)
AVERAGE YEARLY TEMPERATURE OF PUGET
Sowc WATER
22.00
YE1U
Ç
CAL$
PER
.15
ç
15.00
1003 cu. ri.
(EsTlTcD
.10
.10
PER BAG)
ATCR
Sowo
tATER
600
520
f
XIX
TABLE
TYFE OF EQUI
No. OF
PIECES
Rff
AND ESTIM\TED COSTS
COMPLETE
DESCRIPTION
NAME
PRICE
HAMMERMILL
36" x
3
EVAPORATORS
LTV FILM-TYPE Cu TUBES AND BODY
15
LEACH TANKS
WooD 5TAVE
I
90 HP
l6
Ç
x
IO'
3,000
27,000
7,170
WIRE SCREEN
COPPER
1,500
I
WASH WATER TANK
WOOD
STAVE,
I
WASHOUT TANK
WOOD
STAVE, 16' x
I
SALT WASH RJMP
8" SUCTION, 1100 CR1,
15
CIRCULATING PutPs
3" sucTiot, 330 CR1, 6 HP,
15
HEATERS
FouR
i
I
3
8'
x
8'
Y3/uuIT
3
4,500
450
3"
440
200
20'
x
3t
630
250
12 HP
BRONZE
1,200
IO%
120
6,000
I(Y)
60C)
3,000
I
303
250
SEirLING TANKG
6,500
x
HILLSIDE ScREEN
16' x 10' x
25%
600
16' x IO'
10' Cu TUBES, ONE-PASS
WEAK EXTRACT
STORAGE
2
EQUIPPED
x
WITH FALSE L3OTTOMS
I" x
CoST OF
INSTALLATION
3",
WOOD
STAVE
x 3", WOOD STAVE
¡5%
440
366
40
200
5
¡83
(7'
(CONTO.)
conTi t'uo:)
(TABLE
No. ov
PIECES
COMPLETE
PRICE
DESCRIPTION
rJAM
I
EVAPORATOR FEEO TA)<
I
DRIER FEED
L
COST OF
INSTALLAT1O\I
OO
200
SO
6' x 8, x 3", w000 STAVE
lOO
50%
50
WATER HEATER
50
sca.
ri., Cu TUBE
500
50/îow
50
i
EXTRACT COOLER
20
sci.
r., Cu TUBE
200
50/ToN
50
J
CZNTRIFUQ
SuPER CENTRiFUGE TYPE, 5 HP
1,800
/Tou
50
CcuTIrusE PUMP
CEflTRFuGAL,
DECANTING Pui
SA
DRIER RN1P
1/2" BRONZE GEAR,
SPRAY DRIER AND
EQUIPMENT
I
I
I
600'
I
TANT<
IO' x IO
x 3",
WOOD STAVE
HP, I" SUCTION,
'
6ROZE
Ç
150
I
15
150
1
15
too
io%
to
5 HP FAN
25,000
25%
6,250
Pi
75% Cu AND 25% wooD
25,000
5(
12,500
CONVEYOR
RUBBER BELT, 5 HP
3,000
5C
1,500
6c
COMPLETE WITH SCALE
1,000
10%
FILLER
I
AS ABOVE
i/2
TOTALS
CoMBINED TOTAL
l08, 196
100
34,633
142,829
53
AND W#iER CONSUMPTION, WERE NECESSARILY LONG ANO
WILL NOT
A
BE
IN THIS PAPER.
REPRODUCED
FEW ECONOMIES,
SUCH
AS USE OF
CONDENSATE FOR MAKE-UP
WATER, DUAL USE OF CERTAIN PUMPS, AND OTHERS
THE SERIES
COMPLICATED AND
OF TABLES TO
WERE NOT CONSIDERED.
FOLLOW
ARE
SUMMARIES OF THE VARIOUS
IF
THE
PLANT IS BUILT AND PLACED
COSTS, CHARGES, ETC., ANTICIPATED
IN OPERATION.
TABLE
RAW
MTERIALS
COSTS FtR YEAR
BA R K
?
PUSET SOUND
ELECTRIC
446
9,COO,(X)O FALLONS
FILTERED WATER
WATR
9»20,000
83.46
POWER
L)J
92
CU. FT.
1,836
HORSEPOWER YEARS
LIGHTS
9OOlI
STE A M
18,350,000 LBS.
2,750
FAGS
25,500
2,550
8,512
TOTAL
THE PUGET SOUND WATER EXCEEDS THE FILTERED WATER
CECAIJSE
IT
IS
USED
IN
iN AMOUNT
THE EXTRACT COOLERS THE EVAPORATOR CONDENSER,
THIS
AND
IN WASHING OUT THE SPENT DARK.
THE
FILTER PLANT AND PROVIDE COLDER WATER
WOULD
IN
MINIMIZE THE LOAD
ThE SUMMERTIME FOR
ON
CONDENSATION AND COOLING,
j
TABU
I.AND
AND BUILDING COSTS
000
LAND
5,000
RAILROAD SIDING
59,500
BUILDING
PILING
(SIX FOOT CENTERS
40 FT. LONG)
23,120
ELECTRIC WIRING AND FIXTURES
500
PLUMBING
200
OFFICE rURNITURE AND LOCKERS
500
TOTAL
83,820
THE BUILDING PROPOSED WOULD BE OF HOLLOW TILE CONSTRUCITS DIMENSIONS WOULD 0E AP-
TION WITH CEMENT STUCCO EXTERIOR.
PROXIMATELY lOO'
x
200' x 35
TABLE
XXI
I
LABOR AND SUPERVISION FER YE/R
I
PLANT
1NAGER
AT
3,600
3,600
3
OPERATORS
AT
1.25 PER HOUR
9,000
3
HELPERS
AT
l.O0 PER HOUR
7,200
TOTAL
19,800
55
TADU
XXIII
FIXED CHARGES
TAXES AT 2.5%
5,79!
INSURANCE AT .5%
1,158
DEPRECIATION AT 5%
11,582
SOCIAL SECURITY AT 1.5%
297
TOTAL
TA8LE
IKING
18,828
ïV'
GAPITAL
RAW MATERIALS COSTS
8,512
LA3OR ANO SUPERVISION
19,800
FIXED CHARGES
18,828
5,000
INCIDENTALS
TOTAL
52,140
56
TABLE
XXV
CAPITAL (NESTrENT
LAND ANO BUILDING Cosr
i
88,820
EQu;P1ErJT COSTS
142,829
Woc<iwc CAPITAL
52,140
TOTAL
TABLE
283,789
XXVI
G0SS INCt
80,000 LBS. OF BARK
X
0.0304 LBS.
OF TANNIN PER LB. 0F DARK
0.15
X
X
300 DAYS PER YEAR
109,440
57
TABLE
XXVII
ANMJAL COSTS
ANNUAL OPERATING COSTS:
8,512
RAW MA1:RIALS
LABOR
uc SUPERVISION
19,800
4,632
MAINTENANCE AT 2%
FIxED CHARGES, MANAGEMENT1 AND DISTRION GROSS
BUTtON, 25
27,360
INCOME
TOTAL
TABLE
NET
60,304
XXViiI
I
1COEE
$09,440
ANNUAL VALUE 0F PRODUCT
60,304
ANNUAL COSTS
NET
THIS INCOME
IS
i
49, 136
NC OME
AT THE RATE OF t7
ON THE TOTAL
WOULD PROVIDE THAT THE PLANT WOULD 8E PAID FO
INVESTMENT AND
LITTLE LESS
IN A
THAN SIX YEARS.
THE CONCLUSION
IS
THAT SUCH A PLANT WOULD BE
A
GOOD INVESTMENT.
LITERATURE CITED
C
I)
BADGER,
'. L.
HEAT ThA;isFER AND CRYSTALLIZAT$ON
(SwENsoN EVAPORATOR Co1PANY TCHN$CAL
No. E-135.)
(2)
ULLET
¡935.
GRIFFIN, ROGER CASIL::.
TECWUCAL METHODS or ANALvss.
NEW YORK, MCGRAW-HILL LooK Co.,
Isi.
"NEW WHOLt
(3)
WE?ERHAEUSER
LOG
MILL."
8AKER
AND CHIPPER
PACIFIC PULP
INC.,
921.
INSTALLED AT
ANO PAPER
INDUSTRY
¡7:26-30, ¡943.
(4)
SMO0T, CHARLES
BARK AN
C.,
AND FREY, RALPH W.
IMPORTANT POTENTIAL TANF4ING MATERIAL.
Gov'T. PRINTING OFFICE,
¡937.
(U. S. DEPT.
TEMPLETON, H.
L.,
AND
ScRARo,
(6)
(7)
SEA WATER."
¡NO.
CHEMICAL ENGINEERING PLANT DzcICN.
NEW YORK, MCGRAW-HILL LOOK Co.,
WILSON, JOHN ARTHUR.
VOL. I, 2ND ED.
¡928.
IN
AND
¡8:101-102, ¡926.
VILBRANDT, F. C.
EQ.
OF AGRI-
"TANNIN CONTENT OF
E. C.
WESTERN HEMLOI< AFTCR IMMERSION
ENG. CHEM.,
U. S.
566.)
CULTURE TECHNICAL FULLETIN No.
(5)
VESTERN HEMLOCK
INC.,
2ND
¡942.
THE CHEMISTRY OF LEATHR_MANUFACTU.
NEW YoRK, THE CHEMICAL CATALOG Co., INC.,