close

Вход

Забыли?

вход по аккаунту

?

код для вставки
F, N. RAwLlNGs
.im 7, 1947.
2,413,844
ION EXCHANGE TREATMENT v0F SUGAR
6 Sheets-»Sheet 1
Filed Jan. s1.- 1941
HiFi/N TIP/Wfß
Y
r
INVENTOR
FM4/wf /v. @gwn/V65,
BY
Jan» 7» 1947.
F. N. RAwLlNGs
'
2,413,844
10N EXCHANGE TREATMENT oF SUGAR
Filed Jan. 31, 1941
6 Sheets-Sheet 2
¿vf/405750 l
55a
w”
v
-F/ce. 2.
5)/
0 o w/v WAFA@
p/fß¿ ,465/175/8/ 7
Pais/Am ¿- )Prem/ff??
Jan. 7; 1947.
F. N. RAWLVINGS`
2,413,844
IDN EXCHANGE TREATMENT OF SUGAR
Filed Janó s1.` 1941
s sheets-sheet s
QS
INVENTOR.
FFH/VA’ N. /PÄWí//VGIÃ
BY
ATTORNEY.
Jan. 7, 1947.-- A
2,413,844
F. N. RAwLlNGs
ION EXCHANGE TREATMENT 0F SUGAR
Filed Jan. 31. 1941
6 Sheets-Shut 4
mv
bh.
Mb
ATTORNEY.
Jan. 7,1947.
I oN EX
@.bfk
FHNm RTAÉww œw
nl
o.:
s uGÃR
s sheets-sheet 5A
mt \bw
hn
ä.
mw
um
\
LU:m¿mQS2È
m
m3
ß?hâß
f N
„m«È@NN5b2 m
\\
î
#à YÈr
«Èwww»
@îW
`u
@ì
äM
.m
. „n
OI
ß4
N PA
B
W
R
Patented Jan. 7, 1947
_
-
2,413,344
UNITED y STATES PATElsIT]v oFF-ICE
Franklin Nathan Rawlings, Westport, Conn., as- .
signor to The Dorr Company, New York, N. Y., ,
a corporation of Delaware
'
Application January 3l, 1941, Serial No. 37.6,717
9 claims. (Cl. 127-46)
1
2
stituents have been difficult if not impossible of
removal directly from the juice.
So, it is among the broader objects of this in
This invention relates to the production of
crystallized sugar or sugar syrups from sugar
bearing solutions. The invention pertains to the
purification of the juices prior to their being
utilized or crystallized, and it is concerned with
vention to improve the eiliciency of the manu
facturing process as a whole by greater removal
of the impurities among which especially is dis»
solved matter, the removal of which heretofore
has not been practically or commercially suc
the removal from the solution of non-sugar im
purities, a quantity of which is molasses’form
ing, and consequently the improvement of the
cessful. In this connection, the invention aims
efliciency‘ of evaporation and of crystallization
as -well as increasing the output of crystallized 10 at reducing the content of the dissolved inorganic
matter inthe puriñed sugar-bearing solution, as
sugar while reducing its loss into molasses; in
well as the content of the dissolved organic im
short, raising the all-around eiliciency of the
manufacturing process as a whole as well as the
. quality or purity of the product.
purities.
,
A
Another object is the removal of color impart
Sugar-bearing solutions for example beet juices 15 ing impurities from the sugar-bearing solution.
To obtain these ends, it is proposed to subject
should have their non-sugar impurities removed
the
sugar-bearing solution to treatment with or
as far as possible, as they interfere with the em
ganic cation and anion exchangers. Briefly, the
ciency of the subsequent treatment steps. Evap
oration is interfered with because of the lime
essence ,of such chemical exchange treatment is
treatment itself. Also they tend to increase un
electrolytes and dissociate or ionize into cations
and anions in >solution have substituted for their
salts introduced by the conventional puriñcation 20 that those dissolved impurities that behave as
duly the viscosityV of the liquor in the evaporator
as well as to induce foaming.
radicals hydrogen and hydroxyl ions respectively.
That is, the exchange takes place only between
These salts scale
up the evaporators, necessitating their periodical
shutdown for cleaning. crystallization is ham 25 ions of the same electrical charge. This dual
exchange results in the formation of acids in the
pered by impurities causing a (.1) reduction in
cation exchanger due to tbe exchange of the cat
the quality of the crystallized sugar, and (2) loss
ions for hydrogen ions, and in the formation of
of a quantity of the sucrose for crystallization
Water in the anion exchanger due to the exchange
due to molasses formation. To recover some of
the sugar from the molasses, it must be reworked 30 of anions for the hydroxyl ions of the impurities.
This exchange treatment is in distinction from
in an additional process, such as the Steifens
process. The impurities, in fact, are liable to
burden the entire manufacturing process in still
other ways which will be more fully set forth.
The result of the treatment steps for a sugar
preceding pre-treatment or solids removal steps
and is herein called purification.
,
Features of the invention also relate to modifi
35 cations in the clarification phase of customary
bearing solution, for example beet sugar juice
in use at present is to actually eliminate only
ñowsheets, in correlation with the exchange puri
‘those non-sugar constituents which are coagu
fication treatment of the juice. In this way some
of the functions heretofore imposed upon and
lated, or precipitated, or volatilized by the com
bined action of heat and lime .on the juice, car
or clarification steps, may be taken over and per
bonation treatment, when used, serving mainly to
condition the suspended matter for settling, and
to remove excess lime. This, however, represents v
expected to be performed by the solids removal
formed more effectively by the proposed exchange
treatment. According to a speciñc feature of this
invention, in the treatment of beet juices it is
proposed to omit the customary sulñtation, and
only a partial removal of impurities. There re
send the juice from carbonation substantially
main in the juice after solids removal treatment 45 to
directly to the compound exchange station. Thus
as heretofore practiced, appreciable amounts of
calcium is removed by cation exchange insteadv
dissolvedV inorganic matter, dissolved organic mat
ter, color constituents and colloids.v The inor- ~
of by sulñtation.
_ _Other features relate to the use of a variety of
ganic impurities are largely in the nature of
salts which stay in solution. Also the color con 50 organic cation and anion exchangers and espe
' 2,413,844
»
-
»
,
3
Y
.
cially exchangers that resist' an acid environ
ment.
'
to employ either sulfuric or hydrochloric acid, al
‘
though nitric acid (HNOs) and phosphoric acid
Still other features have todo with a mode or
modes in which the exchangers are operated, and
with equipment associated with, or representing
the exchange station.
(HaPOi) may also be among the regenerant acids
l to be used.
Thus, the fundamental reactions of these or#
ganic base exchangers if properly generated, are
equilibrium reactions whereby cations of the so
lution are taken up and replaced with hydrogen
'
The present process for the treatment oi' sugar
juice may be said to comprise clarification by
some or all of the usual solids removal steps now
Moreover, these organic cation exchangers
practiced, and herein briefly referred to as clar 10 ions.
have the capacity to take up sodium and potas
iflcation. Clarification for the present purposes
sium cations which are so prevalent in the non
is a word selected because of the predominance
sugar
impurities of the sugar-bearing solution,
of the solids removal function in the usual steps
Hs well as most all of the other cations contained
ahead of evaporation. Discounting various pos
sible modiñcations such as preferential arrange 15 in the juice. Cation exchangers operating in this
manner are said to be operating in the hydrogen
ment of heaters, modifications in liming, manner
cycle.
of conducting the carbonation, such clarification
steps may be said to include in the treatment of
Chemical mechanism of the anion or acid
beet juice, preliming` heating, liming after heat
exchange
ing; carbonation in one or more stages, clarifica 20
tion, filtration, or centrifuging, or a combination
'I'he anion exchanger to be used ln combina
r of these to remove precipitates, and pH adjust
tion with the above described cation exchanger
-ment by sulfltation. With respect to sugar cane
is likewise of an- organic nature. It has the ca
juice, treatment involves chemical dosing, mixing,
pacity, when treated with alkali hydroxide.; or
heating, fiocculation, and sedimentation of' non 25 alkali carbonates, for instance, NazCOa, NaOH,
sucrose matter, and is generally called defecation.
KOH, KzCOs, NH4OH, to take up hydroxyl ions
The sequence of these steps may vary in different
(OH). Consequently, when aqueous acid solu
localities.
tions as such or acid solutions resulting from the
The thus partally treated juice is subjected to
above~mentioned cation exchangers, are con
further purification by combined exchange treat 30 tacted with these organic acid exchangers thus
ment, with the aid of organic exchangers, some
generated, the anion of the acid is taken up by
times called organolites, that is, treatment by an
the anion exchanger and replaced by the hydroxyl
organic cation or base exchanger operating in the
ion from the exchanger. Exchangers operating
hydrogen cycle and by an organic anion or acid
in this manner are said to be operating in the hy
exchanger operating in the hydroxyl cycle. The 35 droxyl cycle. When the exchange capacity of
emphasis herein upon the organic nature of the
these organic acid exchangers is depleted, they
exchangers is in distinction from those classed as
may be regenerated for reuse by again treating
of inorganic nature.
them with alkali hydroxide or alkali carbonate so
4The principle of the ionic exchange mech
lutions of sufllcient strength.
anisms involved, and the general behavior of the
By using the above described cation and anion
organolite exchangers, will now be set forth as
treatment
in combination, the treatment by cat
follows:
ion exchanger replaces with hydrogen ions some
or all of the cations of the ionic impurities where
Mechanism of chemical reaction of the cationl or
by acid is formed while the anion exchanger re
base exchange
45 places with hydroxyl ions some or all of the
anions passed to it from the cation exchanger in
The cation or base exchanger contemplated for
the form of acid whereby Water is formed. So
use in connection with this invention is of organic
by the combined treatment there is a net ex
nature, and for the purpose of regeneration is
treated with solutions of acids from which active 50 change replacing the salt from the sugar-bearing
solution, with a. molar equivalent of pure and
hydrogen ions are taken up by the exchanger.
evaporatable water.
Subsequently1 when Water solutions of salts are
contacted with these exchangers, the cations of
'
The operation of the exchange mechanism it-`
self might be illustrated as follows: consider the
the solutions are taken up by the exchanger in
exchange for hydrogen ions which the exchanger 55 case that among other salts, potassium chloride is
to be removed from the sugar-bearing solution.
had previously taken up from the acid. Conse
The cation exchanger to be used is of organic na
quently the solution is left containing the corre
ture and for instance of the resinous type, and it
sponding acid of the salt which the solution had
is assumed to have taken up H-ion in the course
originally contained. As an example, if sodium
chloride solution is passed through such an ex
changer, the eiliuent solution contains hydrochlo
ric acid in place of part _or all of the sodium chlo
of its previous regeneration. Upon contacting the
«i0 sugar-bearing solution with the exchanger, the
latter will exchange its H-ion for the potassium
cation of the salt and form hydrochloric acid
(HC1) according to the following equilibrium: Let
herein referred to as exhaustion. After exhaus 65 X repreesnt the organic structure or framework
of the cation exchanger. Then:
tion, for the purpose of regenerating the base or
cation exchangers, it is desirable to treat the mass
or bed thereof, with a solution containing a rela
tively high concentration of hydrogen ion, in other
After all or substantially all of the exchange
words, an acid solution which is strong enough 70 able H-ions have been replaced with potassium
ride. This action continues until the eiïectiveness
of the exchanger is depleted, which condition is
to reverse the equilibrium and to cause the ex
changer to give up in exchange for the hydrogen
ions of the regenerating solution, the ionic im
purities it has collected from the juice. For the
purpose of regeneration it will be usually desirable 75
or other cations, for instance, Na, Ca, Mg, Fe, Al,
as the case my be, from the juice, the exhausted
exchanger is contacted with an acid solution of
suñìcient acidity, such as HC1, in which case the
equilibrium condition is reversed as follows:
9,413,844
s.
(B)
densation of a mixture of an aromatic amine and I
XKàl-H'H-Cl-*XH-i-K‘l'í-Cl
a mono or disaccharide with an aldehyde. '
ready for contacting with- sugar-bearing solution, ,
3. Anion exchangers in. which the active con
stituentv is a basic dye stuiL'such as the vanilinel
while the potassium compound is available in the
spent ~regeneration liquor and thus recoverable.
ous acids and alkalis.
This yrepresents that the >exchanger is again
Other acids, such as H2804, HNOa, may be used
instead of HC1 for regeneration of the cation ex
changer with corresponding'results,
v
blacks, which are insoluble in waterand in aque
'
jecting the sugar-bearing solution lto the action
’ vof the organolite exchangers are the following:
The solution according to EquationA has been
acidiiied because of its reaction with the cation
exchanger, since from the cation treatment it
a. Contacting the solution with ,the exchangers
in different ways, such as:
will have all or part of its anions converted to
their corresponding acid,- and so the chlorides, for
16
instance, will have been converted to HC1.
v By contact of the -solution with 'an anion'ex
¿
Among several variationsin _the ways of vsub
'
l. Passing the solution through beds of the `
exchanger material, and «
2. suspending the exchanger in the solu
tion being treated, and possibly agi
tating the same by hydraulic or me
changer, for- instance, of the resirious type and
.chanical agitation, and
containing replaceable hydroxyl groups, the anion
b. Contacting the solution with the exchangers ~
of‘the acid (HCl) present in the solution accord
at diiïerent temperatures selected to guard
ing'to Equation A is taken up by the exchanger in 20
against inversion that has a tendency to
exchange for the OH-group, andthe following
occur at higher temperatures;`
equilibrium established: Let Y represent the or
ganic structures or framework of theanion ex~
changer. Then:
(c)
YoH+H+ci--l>Yci+HoHï -
In this way the cation as well as the anion of
-the salt constituting the impurity are removed
from the sugar-bearing solution and replaced
with a molar equivalent of water.
„ >
As an example, a conventional system for the
production of sugar from beets comprises .the
following main treatment phases: .Extracting the
sugar from the sliced beets (cassettes)> in dif
fusion batteries for obtaining diffusion juice;
purifying the diffusion juice by'liming, and by
carbonation usually in -two stages followed b_y
sulfltation, and by the removal from the juice
of solids thus coagulated or precipitated, result
ing in what is called thin juice; concentrating
the thin juice by evaporation into thick juice;
subjecting the thick juice to vacuum boiling in
SO2, NO3, the exhausted exchanger is -contacted
with an alkaline hydroxide or carbonate solution 35 vacuum pans to effect further concentration and
to induce the formation of sugar crystals; and
of suilicient alkalinity, such as NaOH, NAiCOa,>
centrifuging the crystallized mass or fillmass thus
KOH, KzCOa, NH4'OH, to reverse the equilibrium
obtained, 'to separate the crystals from their
as follows:
; ‘
menstruum which contains uncrystallized sucrose,
40 non-sucrose impurities, >and coloring matter.
When all the exchangeable hydroxyl (OH)
groups have been replaced with C1 or other anions
from the sugar-bearing solution, for instance S04;
The organic cation or base exchangers and or
ganic acid or anion exchangers which maybe
used in this process include a variety of both.
Among the cation exchangers which may be
used
are:
.I
-
.
'
While this menstruum may be treated for fur
ther yield of crystallized sugar as by re-boiling,
re-puriflcation, re-crystallization, and re-separa
tion` there is a final residue left from which a
45 further' yield of crystallizable sugar can be ob
1. Cation exchangers produced by the treat
ment of humic compounds with sulfur compounds
tained only by special de-sugarizing processes
exemplified bythe Steffens process. If Steffens
which introduce acidv sulfur groups into the humic
substance so treated, such as treating lignite
with concentrated sulfuric acid or equivalent.
Materials of this class which have been stabilized
treatment is not available or too expensive, what
ever crystallizable sugar is left in the molasses
represents a loss in marketable crystallized sugar.
In a conventional process, heat and liming are
by special treatment to prevent color 'throwing
relied upon to coagulate, precipitate, and decom
are also applicable.
pose as much of the non-sucrose impurities as
'
.
possible., Part of the lime goes into solution in
2. Cation exchangers- produced .by treating ma
terials containing aromatic phenols, such as 55 the sugar juice and reacts with some of the im
purities present therein. It combines with any
tannins, with sulfuric acid, petroleum acid sludge,
free acid present such as organic acids, and it
fuming sulfuric acid or equivalent agent which
disnlaces potassium andv sodium from the alkali
causes both the condensation of phenolic ma
lsalts of those acids whose lime salts are insoluble.
terial and the introduction of acid sulfur groups
60 Oxalic and phosphoric acids, and their alkali
to the condensed material.
salts, are typical of this class of compounds
3. Cation exchangers produced by thel con
which `are removed fromsolutions by lime.
densation of aromatic phenols with an aldehyde '
Beet sugar makingpractice furthermore usual
with or without the aid of catalysts.
ly calls for the introduction into the juice of CO2
4. Cation exchangers _produced by the con
densation of aromatic phenols with an aldehyde 65 or CO2-containing gases to react with lime or
calcium compounds such as lime sucrate or lime
and with or without the aid of catalysts and into
saccharate in the juice, to form calcium carbon
which acid sulfur groups have been introduced
>prior to, simultaneous with or subsequent to con- y ate that is effective in collecting and weighting
down as much as possible of the previously co
clensation.>
'
,
A
A variety of organic anion exchangers which 70 agulated and other suspended matter. This gas
may _be yused comprises: `
.
1. Anion Aexchangers produced by the con
densation `of an aromatic amine with an alde
hyde.
»
, sing step is called carbonation.
Bui“l some excess of the calcium resulting from
the liming and present in the juice after car
bonation becomes an impurity and must be re
2.“ Anion exchangers produced byL the con 76 moved because of its tendency to scale in the
"
gnam
,7'
,
evaporators. Hence, carbonation requirescare
ful control, which is carried out usually in two
stages, with solids removal'or filtration in be
tween. The carbonation treatment should be
controlled to leave the juice with a pH of 9.0
for the reason that further reduction in a1
kalinity by C02 would cause certain soluble lime
salts to stay in the juice instead of precipitat
ing as calcium carbonate (CaCOa) , which adds to
the difliculty of scaling and also interferes with
It will now be seen from the foregoing that
improvement as to removal of non-sugars from
the juice, will not only result in increased recov
ery of crystallized sugar of high purity, but is
`also adapted to make itself felt in a cumulative
and beneficial fashion 'throughout the manufac
turing process as a whole, in view of the dimin
ished need for remelting, re-puriflcation, re
evaporation, and re-crystallization, and dimin
ished need for de-sugarization or Stefl’enization
the crystallization of the sugar. It is therefore
customary that the finished carbonated and fil
of the molasses. v
The use of organic cation and anion exchang
tered juice be subjected to sulñtation, that is,
' ers, also termed organolites, as 4employed in the
treatment with SO2 or SO2-containing gases,
.treatment of beet juice according to this inven»
in order to adjust the pH to the desired degree 15 tion, involves the substitution of chemically pro
by precipitating some of the residual lime with
duced water for its molar equivalent of dissolved
out the formation of scale producing calcium
ionic impurities. This should be distinguished
compounds. However, sulfitation causes intro
from a type of exchange treatment involving the
duction of suli'ites into the juice, which in turn
use of materials classed as zeolites. They are oi'
will be found eventually in the finished crys 20 inorganic nature and function by way of neutral
tallized sugar where they are objectionable.
cation exchange only, such as the sodium cycle.
No less objectionable than suliltation for sim->
They merely substitute one non-hydrogen cation
î ilar reasons is the method of removing dissolved
for another.
scale-producing lime salts by a displacement re
By way of contrast between the organolites of
action with sodium carbonate (NarCOa). This 25 this invention and the zeolites, the character and
`substitutes sodium for calcium, the sodium going
function of the latter is outlined as follows:
-»through to molasses with the attendant increase
zeolites are granular solids substantially insolu
in the production of molasses and loss of crys
tallizable sugar. In fact, the inorganic impuri
ble in neutral waters and aqueous solutions.
'I'hese zeolites when .treated or generated with
ties are increased in this instance for the reason 30 strong solutions of neutral alkali salts such as
that the molar quantity of sodium added is in
sodium chloride, take into their structure, as by
polar adsorption, the cations of strong solutions.
Next, evaporation offers the usual diiliculty due`
Zeolites are not stable in the presence of alkali
to scaling as above referred to, because of the
or acid, hence neutral salts must be used for
residual calcium compounds in the juice, and the 35 generating them. As they are unstable in the
attendant reduction in evaporator efficiency.
`
presence of acids, they will disintegrate, and
Then follows crystallization which, according
therefore cannot be used in the treatment of acid
to the practice frequently encountered, is effected
liquids. When hard water solutions are passed
in a succession of three vacuum pans, whereby
through, or treated with these zeolites generated
successive fractions of sugar of successively lower 40 in the above manner, they have the capacity of
purity are obtained. This method is not free
exchanging their alkali ion for the alkaline earth
from certain complications:
'
excess of the calcium removed.
ions and some of the other cations of the water
The boiled-down mass from the first pan is
divided, as by centrifuging, into the high purity
white sugarlwhich, as such, is substantially di
rectly marketable, and its menstruum or mother
liquor containing uncrystallized sucrose, non
sugar impurities, and coloring matter.
being treated, thus softening .the water.
45
Its
boiler scaling capacity can thus be reduced, or
its soap consuming effect be diminished. When
the exchange capacity of the zeolite is depleted,
it can be regenerated by treating it again with
the alkali salt solution, etc., whereupon the zeo
'I'he second pan re-works the menstruum ob
lites can be reused. At any rate, because these
tained from -the first, for recovery of intermediate
are equilibrium reactions in which alkali ions
sugar which is of a relatively lower purity, and
(cations) alone are affected, this involves no
also separated from its menstruum by centrifug
actual reduction in the molar concentration of
ing. But because of its impurity and color, this
the salts in solution.
j second sugar in turn is dissolved or remelted,
As regards the puriñcation of sugar solutions or
sometimes treated with decolorizing substance 55 sugar juice by some form of exchange treatment,
and sent back to Ithe first pan for re-crystalliza
the present invention differs from a known proc
tion and the recovery from it of additional white
ess for the treatment of beet juice by a cation ex
sugar.
changer alone, using a, specified organic exchanger
The menstruum from the second pan is simi
for that purpose, The objection to this process
larly reworked in the thir-d pan for the recovery 60 according to my investigation is `(1) that it can
of brown sugar which may also be re-melted, and
only be employed in the production of soft sugar,
dosed with decolorizing substance, but because of
and (2) that cation treatment alone of the fac
its low purity, is sometimes sent back to the pre
tory juice will produce a juice of low pH because
treatment steps. In fact, its purity is so low and
the cation exchanger converts the salt impurities
its tendency to crystallize so sluggish that it re 65 to the acids of their respective anions. As a re
quires detention in crystallizer tanks for long
sult serious inversion with its attendantl loss of
periods under constant agitation and cooling in
recoverable sucrose would occur if this juice were
order to induce a sufficient degree of crystalliza
concentrated in that acid condition. Further
tion before separation by centrifuge is under
more, only the cation portion of the impurities
taken. The menstruum or residuum or mother 70 couldbe eliminated. »
liquor left over from the separation of the brown
Further, there is a known process relating to
sugar constitutes the ñnal molasses which con
the deacidiñcation of liquids, especially water.
tains the residual sugar that can berecovered for
This treatment covers the treatment of industrial
crystallization only by some de-sugarizing proc
waters exclusively, especially boiler feed water,
ess, such as -the Steffens process above mentioned. 75 by cation exchange followed by abstracting the A
2,413,844 -
9
lected in the exchangers. Indeed from the usual
yellow colored juice fed to the exchangers, an
eiiluent juice emerges therefrom that is water-l
White.
In conjunction with the procedure of regen
erating the exhausted lexchangers I contemplate
acid with metal oxide gels, but is also applicable
to sugar solutions. Up to the present time the
metal oxide gel method of abstracting the acid
does not appear to have been put into practical
use probably because of inherent dîfiiculties d_ue
to the fact that the metal oxides are soluble in
acid solutions and the exchanger beds would dis
the recovery of impurities from the juice as by
products in the spent regenerating liquor. In this
solve and disintegrate, if subjected to solutions ofy
any appreciable acidity. Also the difficulty of
washing out the residual alkaline generating so
lution from the metal oxide gel would be very
diiîicult, and ifv this is not done, the acidity oí
the solutions treated is merely neutralized and not
way I contemplate for instance the recovery of
potassium removed from the juice by cation ex
change, for its by-product or fertilizer value.
Nitrogenous matter also may constitute part of
of the order of 0.05 N, that is, ten times those
which would be encountered with water of the
from'the juice, they must be regenerated if the
the values recovered in the spent liquor.
After exhaustion of the exchangers, that is,
extracted. When sugar solutions are passed
through a cation bed, the acidities developed are 15 depletion of their capability to collect impurities
process is to be made in elîect continuous. An
exhausted exchanger bed is cut out of the line
when a regenerated exchanger has been sub
composition given by Liebknecht. Even concen
trations of the latter magnitude, 0.005, would soon
render metal oxide beds inoperative.
20 stituted therefor.
Preparatory to regeneration,
the .depleted or exhausted exchanger bed must
In the case of the present invention, sugar juice
first have its juice content displaced with water
is subjected to both cation and anion exchange,
and this displacement preferably takes place
both exchangers being of organic nature. One oi
from the top toward the bottom, or in a down
a variety of organic cation exchangers considered
suitable for the purpose of this invention is of the 25 ward direction because the juice is heavier than
the Water. Next comes a back-washing of the
resinous type such as exempliiied in the U. S.
bed
in an upward direction with wash water to
patent to Holmes No. 2,191,853, where the ex
remove from the bed as much as possible of the
changer is described as a synthetic resin of the
polyhydric phenol-formaldehyde type which is
collected non-ionic impurities and >especially
changer as an insoluble resin-like product obtained '
_the beds is preferably from top to bottom, or
downwardly. The regenerant'removes from the,
bed those impurities that have been collected
by ionic exchange. The collected ionic impuri
sulphite'd to a degree such that its sulphur con 30 those in solid phase. The next step is the regen
eration phase per se. It consists in passing the
tent is not less than 2.4 per cent. An organic
regenerant through the bed until the bed is re
anion exchanger considered suitable for the pur
generated. In a cation bed, the regenerant is
pose of this invention is also of the resinous type
an acid whereas in the anion bed, it is an alkaline
and is exemplified in the U. S. patent to Adams
reagent. The passage of the regenerant through
and Holmes No. 2,151,883, describing the ex
by the reaction of formaldehyde with an aromatic
amine. Exchangers of the type contemplated for
use in connection with the invention, are substan
tially stable in the presence of acids and alkalis.
In this way the cation exchange treatment is
supplemented by treatment with an acid or anion
exchanger which serves to remove the acid anionsl
40 ties are removed from both cation and anion ex
changers as a salt in the spent regenerating liq
uor.
After regeneration has been completed, unused
regenerant or regenerating liquor must be well
remaining unaffected by the cation treatment,
and replace them with hydroxyl ion, thus -form 45 Washed'ffrom the exchanger beds by means of
wash water. In the case of the anion exchanger,
ing water, and reducing the >molar concentration
if any unused regenerant is left in the bed, when
of the ionic impurities. This combined ionic ex
sugar-bearing solution is newly supplied thereto
change results in a juice of sufficiently high pH
again it will react with ‘the unused regenerant
to be concentrated and crystallized without sub
and be rendered neutral thereby. That is to
` stantialV inversion. A substantially neutralized 50
say, the acid produced in the juice by the preced
puriñed sugar juice can be obtained according
ing
cation exchange treatment will be neutralized
to the practice of this invention, along with the
by the unused regenerant, and the salt will re
removal of the cations and anions. Among the
main in solution'.
inorganic impurities removable from the juice by
The color constituents have been observed toA
this combined treatmentl will be potassium, so 55
leave the beds with the spent regenerant sub
dium, calcium, magnesium, iron, aluminum, chlo
stantially from the anion beds, although possibly
rides, nitrates, and sulfates.
some may be removed in the bed washing steps.
In the foregoing, as far as the operation of the
When cane juice is treated in a manner accord
exchangers is concerned, there has been referred
to those impurities of the sugar juice that are dis 60 ing to this invention, the situation is substantially
as follows:
’
solved therein and are ionic, that is, subject to
The usual practice of cane juice clariñcation
collection in the organolite exchangers by chemi
differs from` customary beet juice treatment in
cal replacement. But it is a discovery of mine,
that the cane juice is subjectedA to treatment
that by the practice of this invention other im
purities of the juice are collected in the exchang 65 which vinvolves mainly liming the juice in com
bination with heating to coagulate the impurities
ers, that are organic and some of which are prob
thus coagulatable, followed by solids separation
ably non-ionic. I have also discovered that by
steps. In cane juice technology, these treatment
practicing this invention, colloidal matter in the
steps are known as defecation, and according to
juice is collected in the exchangers, and therefore
colloids -in the juice, which incidentally are sub 70 'current practice this is usually understood to con
vey that the liming of the cane juice is carried out
stantially organic, may be said to belong to a
in a manner to leave the juice with a pH of the
group of impurities removable by this process,
which impurities are herein classed as non-ionic.
' It is a further discovery of mine that color im
parting constituents of >the -juice .are >also col
order from around 6.5 to around 8.6. The sus
pended solids are usually removed from the juice
75 by a clarifier which may be followed by a iilter
2,413,844
11
to handle the clarlñer sludge, and clariñed juice
well as impurities, this suggests the possibility oi’
eliminating the sugar refining treatment.
and clear ñltrate are then sent to evaporation
without an attempt to reduce the alkalinity of
Otherwise the treatment of cane- juice accord
ing to this invention will beneñt the operations
the juice by intermediate treatment steps such
as might correspond to carbonation and sulfita
tion steps.
per se of concentration and crystallization substantially in the manner set forth in connection
with the discussion of beet juice treatment above.
The invention possesses other objects and fea
tures of advantage, some of which with the fore
'
In the defecation processes currently used in
the treatment of cane juice, in distinction from
the coagulatable matter there have not been re
moved to any appreciable extent' ionic impurities 10 going will be set forth in the following descrip
comprising inorganic matter in solution, and
tion. In the following description and in the
they have largely gone through to molasses with
claims, parts will be identiñed by speciiic names
the attendant loss in sugar. Of the non-ionic
for convenience, but they are intended to be as
non-sugars, comprising dissolved organic matter,
generic in their application to similar parts as
only a portion has been removed, the rest going 15 the art will permit. In'the accompanying draw
through to molasses.
ings there has been illustrated the -best embodi
The elimination of the inorganic non-sugars
ment of the invention known to me, but such em
is important because they tie up deñnite amounts
bodiment is to be regarded as typical only of
of sucrose in non-crystallizable form.
many possible embodiments, and the invention is
Color removal is a problem in the treatment of 20 not to be limited thereto.
cane juice, and current defecation processes are
The novel features considered characteristic
incapable of removing it unless considerable SO2
of my invention 'are set forth with particularity
or carbon is applied.
in the appendedl claims. The invention itself,
In the treatment of cane juice, liming normally
however, both as to its organization and its
is to be kept to a practical minimum and sub 25 method of operation, together with additional
stantially within the range above indicated, be
objects and advantages thereof, will best be un
cause the strongly alkaline lime is the cause of
several detrimental effects in the further treat
ment of the juice. The high rate of liming which
derstood from the following description of a
speciñc embodiment when read in connection
with the accompanying drawings, in which:
precedes the carbonation of beet juice is current
Fig. 1 is a ilowsheet for the treatment of sugar
ly not extensively employed and consequently 30 bearing solutions in general, indicating the main
carbonation itself is seldom resorted to. The al
treatment phases and comprising puriñcation by
kalinity is very carefully controlled in order to
treatment with exchangers, and the regeneration
avoid acidity and consequent inversion on the
of the latter.
one hand and in order to avoid undesirable ex
Fig. 2 is a i‘lowsheet in the manner of Fig. 1,
35
cess of alkalinity on the other hand. Yet there
is encountered in cane juice treatment a con
siderable degree of scaling which requires fre- `
quent cleaning and overhauling of the evapo
rators, as the inorganic impurities of the def
ecated cane juice contain a larger proportion of
but pertaining to steps in the regeneration
Phase.
Fig. 3 is a ?lowsheet more particularized with
respect to pre-treatment or clarification steps
40 employed in the treatment of beet juice, and
also discerning between the exchange treatment
station and certain associated equipment there
for.
calcium than is found in clarified beet juice.
But when the defecated juice is subjected to ionic
exchange treatment according to this invention,
'
Fig. 4 is a ilowsheet similar to that of Fig. 3, .
calcium and other ions are removed from the 45 applied to the treatment of cane juice.
juice in the cation exchanger, so that the scaling
Fig. 5 is a more particularized although di
diiiiculty is reduced.
agrammatic showing of the exchange treatment
Potassium, sodium, and other impurities or
batteries proper` and associated equipment there
salts also present are removed from the juice by
for.`
'
cation and anion exchange as previously dis~ 50 Fig. 6 is a diagrammatic showing of the ex
cussed in connection with the treatment of beet
changer batteries proper with the exchanger
juice.
,
elements being interconnected in a manner to
The low degree of liming of cane juice is fur
permit the cutting out and cutting in of the ex
ther practiced because of the combining of lime
changer beds, and also showing connections for
‘with organic compounds such as glucose in the 55 Wash Water and regenerant solution respectively.
juice. Calcium gluconates, if formed, add to the
Fig. '7 shows a continuous sampling arrange
loss of sugar in molasses, and increase the vis
cosity of the mass in the vacuum pans and there
by retard and reduce the eñ‘iciency of crystalliza
tion. Treatment according to this invention 60
will reduce that difiiculty, as the calcium ions
of the gluconates are also collected in the cation
exchanger, and the glucose left as such in the
Juice.
'
It follows that in practicing the invention the
permissible limits of induced alkalinity in the
juice may be extended, if desired.
ment for a continuous pH indicator or similar
instrument.
Fig. 8 is a curve indicating the exchange char-_
acteristic of a cation exchanger.
1
Fig. 9 is a diagram showing the operation of
a cation exchanger battery in combination with
an anion exchanger battery, in regard toacidi
ñcation and de-acidiflcation of the juice.
Fig. 1 represents a more broadly conceived
showing of the phases relating to the treatment
of sugar-bearing solutions as a whole, than do the
subsequent iigures. In that respect it will be
noted that the showing in Fig. 1 is so to speak
even a relatively pure crystallized cane sugar 70 generic to the showing in Figures 3 and 4 repre
may nevertheless appear strongly colored. Spe
senting the application' of this invention to the
cial and separate refining treatment of the crys
treatment of beet and cane juice respectively.
tallized raw cane sugar is currently needed to
The relation of Fig. 5 to the other figures is that
purify and whiten it. Since the treatment ac
it represents a more detailed showing although
cording to this invention will remove. color as 75 diagrammatically of the exchanger station and
Furthermore, cane juice has strong color char
acteristics and is dif?cult to de-colorize, so that
8,413,844
13
14
entering a second carbonation stage or tank I9
which may be substantially similar to the ñrst
associated equipment indicated in Figs. 3 and
4, and shown to include a cooling station and a
filter station for the juice prior to its entry into
the exchanger station proper. Fig. 5 thus also
continuously operating'carbonation stage I3, the
gas entry being shown at I9“ and gas exit at
l9b. Here carbonation is continued in terms of
alkalinity unti1 a point corresponding to a pH
of 9.0 is reached.l Here again carbonation must
represents a showing in terms of equipment of
the exchange treatment or puriiication treatment
phase indicated in Fig. 1 tov follow the pre
treatment phase, and followed by evaporation.
The crystallization phase shown to follow evapo
be regulated very accurately in order to guard
against the formation of soluble carbonates which
ration is also affected by the consequences of 10 would stay in solution in the juice as an added
non-sugar or impurity adapted to contribute to
scaling.
1,- a procedure which must run parallel to the
Hence, at the proper point second carbonation
treatment of the juice.‘is the regeneration of
is broken 0H, and the carbonated juice sent as by
chemically depleted or exhausted exchanger
beds. So they are indicated invFig. 1 to be seg 15 way of a flow connection 20 through a filter press
2 l, and then by way of line 2 l“ on to a suliitation
regated or taken out of operation for regener
station or tank or tower 22 where it is treated
ation, while fresh or regenerated beds may be
with SO2 or SO2-containing' gas until the de
switched in for re-use instead. There is also
this invention. Furthermore, according to Fig.
indicated the possible operation of recovering of
values or by-products from the spent regener
sired pH is established in the juice, the gas being
20 indicated to enter thetower as at 22“ and, after
contacting the body of juice in the tower, to
leave the tower as' indicated at 22. Precipitate'
which may have been formed in the suliitation
changer beds there is involved a preparatory or
_station is removed from the juice when it is
washing operation which precedes their regener
ation proper, to displace and wash out from them 25 next sent through another filter press 23, re
sulting in a clarified juice 24, called thin juice.
the juice and other residual matter. Another
Heaters for the juice are variously employed
washing operation is subsequent to regeneration
proper, for the purpose of removing unused or ‘ where desired throughout the treatment process
so far described, but are herein not particularly
residual regenerant solution prior to putting the
beds back into» service. Therefore, Fig. 2 shows 30 shown. Various modifications in the operations
relating to limin‘g, carbonation, and solids re
in a diagrammatic fashion similar to Fig. 1 the
moval are possible in the light of various prac
sequence of such operation, and incidentally in
conjunction. with possible recovery of values or
Still.' `the juice which results from what is here
by-products from the spent regeneration liquor.
in termed the clarification phase of the treat
It will be understood that in the case oftrea-t
ment process, has left in it a quantity of im
ing beet juice the raw or diffusion juice’may first
purities and dissolved matter comprising scale
be subjected to a pretreatment or clarification
ation liquor.
`
In the treatment for regeneration of the ex
tices.'
.
"
`
forming salts and other inorganic salts, organic
As an
dissolved matter, and color constituents. The
example, according vto Fig. 3 this comprises
sending the juice l0 through a heater Il, and 40 undesirable effect of these non-sugars which
heretofore were currently not removed from
then through a first liming tank or station I2
sugar juices, contributes to increase of molasses
where the> addition of lime is indicated as at
formation, loss of sugar, scaling, lfoaming, re
Il“, the lime added in -terms of CaO usually
- namely for removing coagulatable solids.
duced efliciency of evaporation and crystalliza
being on the order of _0.7 to 1.5/100'c. c. of juice _
in a straight house, and 2.2-2.7 g./100 c. c. of 45 tion, as -well as .reduced total eiiiciency and econ
omy, as has herein been indicated. '
juice in a:_Steñens house_._ Lime alkalinity and
heat result in »the coagulationof coagulatable
solids in the juice. _
f
-
As regards the _quality of the‘product itself, e
that is, the purity A,of the ~sugar, there is often
found in-beet sugar an SO2 content which is un
'
The limed juice is shown as being sent through
desirable.- Furthermore, the ash content com- Y
- a first carbonation station or tank vI3 which is 50 prising
traces of potassium and nitrogen found to _
herein indicated to be Aof the continuously oper
be present in Ithe iinished beet sugar will sustain
ating type.'v Thus the lirned juice is subjected
the growth of spores, allowing Athem to multiply _
to contact _with CO2 Vor CO2-containing gases to l
produce a- reaction‘with'the calcium compound
or lime, forming calcium carbonate (CaCOs) in
tended for collecting and weighting down the co->
-agulated matter in the vjuice for the purpose of
55
in storage. The presence of these impuritiesin
candy making causes the appearance of foam ~
and scum when boiling. The 'effects ‘from the
presence of spores sustained 'by the impurities are
also noted in the manufacture of beverages.
However, these undesirable effects can be mini
The gas enters at the bottom of the car-bona
tion tank as at I3“ and after passing through the 60 mized ifA the juice clarified in the above manner
issubjected to purification treatment by ionic
body of juice escapes upwardly as shown vat |31’.
exchangers according to the invention. The clari
But, ñrst carbonation is carried only to a point
ñed juice passes through a'ilow'connection 25
of alkalinity well above neutral, at which sub
` to a purification treatment station 'collectively
stantially all of that fraction of coagulated mat
ter can be caused to settle which at lower al 65 designated by the numeral '26 »and later on to be
sedimentation.
»
.
_
l
_
_
kalinìties of the juice might become re-dissolved.
The juice containing this precipitate enters a
clariñer I4 which may be of the multiple tray
Dorr type known to be used in this connection.
discussed more lspecifically in .connection "with
Figures 5.and 6. ' Sumce-it to say at this point
that the purification station comprises >a cooling
station 21, a ñlter station 28, and thevexchanger
The settled solids or underiiow sludge from the 70 station 29 proper, through which three'stations
the juice may be passed in succession;
' Ä
.
clariñer then passes to- what _isA shown to be a
A by-pass ñow connection 30 having a .valv
continuous rotary filter l5 for instance of the
30“L is shown «to lead from the'ilow connection 20
Oliver type. 4The -filter cake is discharged as at
into the ñow connection 25, _so that the sulñtation»
I6, and the clear juice or ñltrate I1 joins the
clear overflow juice I8 from the clariiier` in 75 station 22 and filter press `23 can be lav-passed.>
2,413,844
15
16
~
This provision permits to omit sulñtation, in
order to send the carbonated juice as such to the
purification station 26. In this way the burden
of pH adjustment currently effected by sulfltation
may be placed Where it can be realized without>
the drawback of suliitation, namely, by calcium
removal through cation exchange.
'I'he juice thus purified in the purification sta
tion 26 can be evaporated more readily and effi
discussion of its operation as hereinafter given,
for the purpose ofrthis invention may be said to
apply to both beet juice and cane juice treatment
substantially alike. Consequently, in Fig. 4 the
purification treatment station is also shown to
‘comprise a cooling station 43", a filter station 43h,
and an exchanger station 43a. 'I'he thus puriñed
cane juice may be sent to evaporation 44 and
then to crystallization 45.
ciently in evaporators 3l, and due to the reduc 10
Sugar juices, such as beet and cane juice, may
tion in molasses it can be handled with greater
be said to differ from eachother by reason of
efficiency in crystallization station 32. Conse
some difference in the impurities contained in
quently, there is -apt to be a greater direct white
them, and that difference determines the respec
sugar yield from the first vacuum pan, and con
sequently, fewer intermediate and brown sugar
strikes to be boiled. This in turn means that
relatively less sugar from the intermediate pan
needs be re-melted and returned to and re
crystallized in the first or White sugar pan, and
tive types of pre-treatment currently employed
for .their clarification. »And so, by the same token,
the respective clarified juices differ, because of
some difference in the amounts or proportions
and types of non-sucrose, impurities andv color
constituents, still left in them even after clari
in turn relatively less brown sugar from the third 20 flcation. In present-day cane sugar making the
pan be re-melted, clarified, re-evaporated, and
resulting cane sugar is known as high grade sugar
re-crystallized. By the same token, that is, re
however unreflned, as there are left in it im
duction of the quantity of molasses, the relative
purities, and especially color, not normally pres
load upon the centrifuges is reduced and their
ent in factory ñnished beet sugar as represented
operation improved. The need for molasses treat 25 by the white sugar aforementioned.
ment by desugaring or SteiTenizing is diminished.
Yet, when the respective juices are submitted
Economies in fuel, steam, apparatus, machinery,
to the exchange purification treatment according
maintenance and labor are still further conse
to this invention, there is effected the removal of
quences of this invention. In short, the advan
non-sugars, dissolved, inorganic, organic, ionic,
tages gained from the intensified purification of 30 non-ionic, color constituents, and colloids which
the juice, as effected by this invention, are dis
currently have not been removed by the pre
tinctly cumulative throughout the treatment
treatment from the juices. That is to say, the
process as a whole.
'
exchanger may be variously burdened more with
The showing in Fig. 4 diagrammatically indi
one type of an imp-urity than with another, de
cates the case of cane juice treatment. As an 35 pending upon the respective prevalence of the one
example, the raw jui-ce 33 enters a liming stage
over the other in the respective juices. For ex
or tank 33tL where it is dosed and treated with a
ample in ’beet juice potassium and sodium are
suitable calcium compound such as lime, that is,
currently outstanding inorganic impurities, while
calcium hydroxide (Ca(OI-I) 2), the introduction
in canejuice calcium m-ay be in excess of other
of the lime being indicated at 34. This opera 40 impurities. To take care of'each respective situ
tion is usually known and herein termed as pre
ation in the exchangers is a matter of their oper
liming in distinction from an additional subse
ation and balancing, a matter which will be taken
quent liming operation. 'I'he pre-limed juice is
up hereinafter when discussing operation. It
passed through a heater 35 and from there to a
might be said of this exchange purification treat
second liming station or tank 36 where lime is
ment of sugar juices, if practiced according to the
shown to be added as at 31. As a result of heat
invention, that it has an equalizing influence as
and lime treatment, a quantity of the impurities
regards the treatment of both kinds of juices, for
is now. present in the juice in a coagulated state.
in both the diiliculties due yto the presence of .the
This juice is then sent by way of line 38 to a
non-sugars may be relieved, and the resulting ad
clarifier 39, for instance a multiple tray clarifier 50 vantages are similar as regards quality of the end
of the Dorr type, in which the coagulated, sus
product and as to factory operation.
pended and settleable matter is removed as un
The treatment according to this invention be
derflow or sludge indicated at 40, While clarified
cause of greater elimination of impurities from
juice leaves the clariñer as overflow 4I. The
the sugar juices results in numerous improve
underñow or sludge 40 is further treated in a 55 ments and increased overall efficiency throughout
filter operation wherein a continuous rotary filter
the manufacturing process, and notably in the
42, for instance an Oliver, may be used. In such
concentrating and crystallizing operation. Among
instance, however, because of the diñiculty of
such improvements are:
obtaining a. clear filtrate in a rotary ñlter from
Elimination of -scaling in evaporators, due -to
cane juice sludge, this filtrate is usually sent back 60 elimination of inorganic matter including lime
to the preceding clarifier` for retreatment together
salts.
'
_with the bulk of the juice, and this return is
Faster and smoother evaporation during con
herein represented by line 4IEL from the filter 42
centration, due to greater elimination of colloids
joining the line 38 of the juice entering the clari
fier 39. Filter cake is shown to leave the filter 65
as at 42a.
The overflow or clarified juice 4| is then sub
jected to purification treatment by passing it to
and 'soluble impurities.
`
Increase in vacuum pan and centrifuge capac
ity, due to elimination of the` aforementioned im
purities.
Better quality of sugar both as to appearance
a purification treatment station collectively desig
and by analysis. Ash content will be reduced,
nated by the numeral 43, and which by way of 70 especially the objectionable sulntes and sulfates.
example may be said to correspond in general to
Far-reaching reduction in impurities minimizes
the- purification station designated by numeral 26
the. chance for undesirable spores .in sugars or
in Fig. 3, and shown in greater detail in Figs. 5
syrups to multiply.
and 6.
And so, the more detailed showing as in
Materially less molasses is produced, due tol
Figs. 5 and 6 of the purification station, and the 75 reduction of those impurities in the juice which
»,uaaca
'i7
are conducive to the formation oi'
A
concurrent increase in the yield of sugar is e!
,
fected.
Economies of steam and fuel inthe operation
of the plant, as well as other economies are ef- '
fected, for instance due to a relative reduction in
18
found in treating beet juice obtained after pre
treatment including sulfitation, at a temperature
on the order of from 90 to 100 degrees C., that
cooling to from 20 to 30 degrees C., would cause
the appearance of an appreciable amount of selec
tively congealed non-ionic impurities in the juice.
Such selectively congealed substances if left in
the juice may lead to clogging and gradual foul
ing of the exchanger beds, and at any rate they!
ferred to.
may lower the exchange emciency by coating the
Greater freedom in the conduct of pre-treat l0 granules of the exchanger material. I propose
ment steps.
'
thus to selectively congeal and remove non-ionic
' There will now be given in connection with
impurities by intercepting them asin the filter 51.
Figs. 5 and 6 as an example the description of the
‘ I may also choose or prefer to operate the ex
purification station comprising the exchanger
changer beds at temperatures below those pre
batteries proper and certain accessory or asso
vailing in the juice according to current treat
ciated equipment, and a discussion of its opera
ment practices, because the juice in passing
tion. The disclosure made in Figures 5 and 6 is
through the exchangers is temporarily acidiñed.
by way of example and capable of modifications.
An acid environment develops in the exchanger
In Fig. 5 pre-treated or clarified juice 46, still hot
due to the acidifying function of the cation ex
the requirements of re-melting, re-puriflcation,
re-evaporation, re-crystallizing, etc., initially re
from Vthe pre-treatment operation, is supplied 20 changer, hence, by keeping operating tempera
through lines 41 and 41‘ and through valves 48
- tures in the exchangers 'reasonably low, a con
and 49 to the cooling station here shown to com
dition can be avoided in which acidity and higher
prise two sections or stages, namely> a heat ex
temperatures coact to cause inversion of the
changer 50 followed by a supplementary cooler
lsucrose in the juice, invert sugars being non
or booster 5I. The juice first passes through the 25 crystallizable and adding to the production of
heat exchanger 50 where it is cooled to some de
molasses. In this way I have treated beet juice
gree and economically by utilizing as a cooling -
obtained under factory operating conditions that
medium cooled juice that has already gone
from al1 appearances remained free from inver
through subsequent exchanger treatment and is
in turn re-heated for further processing. as will 30 sion.
From the foregoing it will th-us be understood
be described. By way of valves 52 and 53 the i that by operating the exchanger station with the
juice then passes into the supplementary cooler
cooling station and the filtration station ahead
5I where its temperature is lowered to the desired
of it, a dual advantage can be attained.
degree by means of a cooling water supply indi
Thereafter the juice enters the cation ex
cated by inlet 5|ß and outlet 5I". The cooled 35 changer batteryl 60 herein shown to comprise
juice passes on through valves 54 and 55, and
three exchanger stages or units or 4beds 60a, 50",
then through a line 55a and valve 56 into a fil-ter
60°, connected in series. The juice enters the
station represented by a filter 51 which it leaves
unit lilla at the bottom, rises through the bed of
through a valve 58 and a line 59 admitting it to
exchanger material maintaining the same in
the exchanger station “E” proper which is shown 40 mildly agitated condition, and from the top there
to comprise a number of cation exchanger units
or beds, operating in series and herein termed a
of flows through a connection 10 to the bottom
of the next bed 60h, and so on up through bed 60h,
down through connection 1I, and up through bed
of anion units or beds numbered 6I. In order
60°. `At this point the juice may have reached
to operate the cooler and filter station just de 45 a maximum of acidity because it has received
scribed, it will be necessary `to keep other valves
hydrogen ion from the exchanger in exchange
and certain by-pass connections closed. For this
for the cations of dissolved and ionized salts in
reason the valves 62, G2“, B3, 63a, and if desired
the juice, which are collected by the exchanger
also valve 64 should be kept closed. On the
chemical mechanism previously explained. In ~
other hand it is possible through by--pass lines 50 by
this
acidiñed condition which might be called its
65, 5B, 61, 68, 69, and by operating proper sets of
battery designated by number G0, and a battery
valves, to use one of the cooler sections alone or
both in series, and to do so in each instance with"
intermediate or transitional exchange condition,
the juice is transferred to the anion exchanger
battery 6| herein also shown by way of example
or without using the filter 51. Also the filter 51
to comprise three stages, units, or beds, numbered
may be used alone, that is to say, with cooler 55
6I“, Bib, `6|° respectively and which are connected
The
cooler
station
as
well
as
.thev
station idle.
in series by flow connections 12 and 13 enabling
filter station may be by-passed by .sending the,l
the juice to flow upwardly through the beds in
juice through lines 68 and 69 directly into line 59
succession.
'
and into the exchanger station "E.”
The juice may -be transferred from the cation
I have discovered that cooling the juice ob 60
exchange beds to the anion exchange beds di
tained after pre-treatment, isapt to coagulate
rectly through lines 14, 15, 16, 11, with -valves
and precipitate some impurities in the juice.
18, 19, 80 open, while valves 8|, 82, 83 are closed,
'I‘his I have found to be an unexpected phenome
or it may be treated intermediately as will herein
non in that ordinarily great care is taken not to
permit the temperature of the juice to drop below 65 after be described.
I may choose to connect the beds in such a
what are normally considered safe limits for
manner that an anion bed alternates with a_
maintaining desired treatment conditions. Ordi
cation bed. In that case the juice passing
narily the temperature of the juice going through
through the series is repeatedly acidiñed and de
pre-treatment is repeatedly boosted up at various
‘
treatment stages, and heating is provided before 70 acidiñed.
In view of possible gas formation for instance'
the juice enters the evaporators. As part of this
in the cation exchange battery 60 I provide means
invention I propose, if I so choose, to operate the
for evacuating the juice after it leaves the
exchanger purification station at temperatures
cation battery 60. Such means are represented
lower than those ordinarily prevailing in the juice
according to current practice. For instance I have 75 for instance by an evacuator device of some known
v19
y aus,
construction, functionally interposed between thev v»
cation exchange battery-60 and the anion ex
change battery 6|, and indicated as at 84. If it
is desired to switch the evacuator into operation,`
to va heater 99 where its temperature is further
>raised to a point desirable prior to sending it
.through valves |00 and |0| into line |02 leading
to the evaporators, with the by-pass valve |03
î meanwhile closing the by-pass line |04. By open
ing the by-pass valve |03 and closing the valves
valve 18 is closed, and so are valves 85 and 83,
whereas valve 8|, valves 86 and 81, as well as
valves 82, 19, 80, remain open. The juice is then
free to pass from the last cation bed 60c of thebattery 60 through lines 14 and 89 to the evacua
98 and |00 the heater 99 can be out out of service.
The pre-heating operation inthe heat exchanger
50 may be cut out by closing valve 95 and send
tor 84, and from there through lines 90, 9|, 16, 10 ing the ñnished juice from line 93 through valve
11 to the ñrstbed 6|“ of anion exchange bat
94, and also through valve |05 to a heater |06,
tery 6|.
and from there through valves |01 and |08, and
I further interpose and arrange for optional
through the line |02 leading to the evaporators,
use between the cation and the anion exchange
valves |0| and |09 meanwhile being closed.’
batteries a filter device or station indicated as at 15
With respect to the exchanger beds it is de
88. This ñlter can be cut out of operation by
sirable to maintain the operation quasi-continu
closing the valves 83 and 85, but can be put in
ous and as nearly uniform as possible. This calls
for cutting out a bed whose exchange capability
believed to be self-explanatory from Fig. 5 of the
considered depleted or exhausted, and cutting
drawings. In this way the juice is passed through 20 is
in a fresh or regenerated exchanger bed whenever
operation by proper use of the valves shown, and `
open valves 18, 82, 85, 83, with all other valves
closed, and through lines 14, 15, 9|, 92, filter 88,
and lines 92a and 11.
With the valves and connections shown the
juice can be caused to pass through the evacuat
ing device 84 and the filter 88 in series, forcon
required. Depletion of the exchange capability
of an exchanger bed proceeds substantially in the
following manner:
An individual exchanger body or bed of a cer
tain exchanger, material will have a characteris
tic curve according to which its chemical exhaus
ditioning prior to entry into the first bed iìl‘L of
tion proceeds as a function of the volume of solu
the anion exchange battery 6|.
tion or sugar juice passed through it under given
It will be remembered from the earlier explana
flow conditions.` For a certain- period of time a
tion herein given that in the anion exchange beds
fairly steady or even increasing rate of conver
the juice having previously been rendered acid in 30 sion or exchange intensity will maintain, but will
the cation exchange beds, is gradually de-acidi?led
because of the anionic exchange function whereby
'OH-ions from the anion exchanger are exchanged
for the anion of the acid in the juice, forming
water. Thus there takes place by the combined
or complementary action of the exchangers, a re
placement of dissolved inorganic ionic salt by a
molar equivalent of water, as the cations and
anions of the salt have been collected by their
respective exchangers.
'
Aside from replacing salts with water in this
complementary fashion, it should also be under
stood that the cation exchanger as well as the
anion exchanger each per se may collect respec
tive ions from other than purely inorganic ionic
substances. An example is the removal by the
cation exchanger of the calcium ion in the pre
A
begin to drop off markedly when the so-called
point of “break through” of such an exchanger
is reached.
Weakening of exchange or chemical force de
velops because of a gradual decrease in exchange
ability or power of the exchanger. To begin, the
exchange intensity in the bed is greatest at its
inlet end where fresh exchanger meets fresh
40 juice, but is less towards the outlet and.where the
exchanger meets juice which has already had a
quantity of its constituents converted, exchanged,
or removed by the exchanger. Consequently, an
exchanger becomes exhausted in zone wise fash
ion progressively from the inlet end to the outlet
end. It is therefore well to distinguish between
the local exhaustion in a zone of the bed and
the average exhaustion of the entire bed.
This consideration is of practical consequence
viously mentioned gluconate found in pre-treated
cane juice.
Similarly, anions may be taken up 50 for the establishment of quasi-continuous operaby the anion exchanger from compounds other
tion of the exchanger station.
than the straight inorganic ionic salts. In this
Referring to Fig. 5 as an example, in the oper
way the cation beds as well as the anion beds
may be burdened with the removal of respective
ions from the juice, other than those which con
stitute the dissolved inorganic salts that are re
placed with water. The resulting shifts in burden
are taken care of by adequate capacities of the
exchangers. Further imposed upon the exchang
ers is the removal of dissolved organic, and non
ionic matter, and of color constituents, and per
haps of superñcial matters attaching itself to the
surface of the granules of the exchanger mate
rial.
ation of the cation exchange battery 80, when the ~
ñrst bed 60”» has reached a predetermined de
gree of exhaustion, it is cui'I out, and the next
bed 60b which is less exhausted, is made to oper
ate in place of the first. The third bed |i0c which
may be still less exhausted is then caused to func
tion in the second place, while a new or regen
60 erated bed is cut in to operate in the third place.
The cation battery may then continue to operate
Until again the exhaustion of the first bed neces
sitates a change. A similar routine may be fol
»
lowed with respect to the operation of the'anion
The puriñed‘or as it is herein called, the iin 65 exchange battery 8|. A practical method of op
ished juice leaves the last anion exchanger bed
erating a battery such as the cation exchange
6|c through line 93. If valve 94 is closed and
battery 60 or the anion exchange battery 6|, is
valve 95 open, the juice, under conditions here
to allow the degree of average exhaustion of the
'considered is relatively cool, and will pass through
ñrst bed to develop not further than is justified
a line 96 to and into the heat exchanger 50 ahead 70 by the `reserve exchange capacity represented by
of the exchanger station. After thus having
the other, less exhausted beds of the series. In
cooled down the incoming juice, and in turn hav
other words, a permissible limit of exhaustion of
ing absorbed or recovered heat from it the iin
the ñrst bed should be determined by and cor
ished and pre-heated juice passes from the heat
respond to a state of minimum exhaustion of the
exchanger 50 through a line 91 and valve 98, 75 last bed. Still otherwise expressed, a change or
y’
» 2.41am
21
through in' order to effect a smooth removal o!
the juice which has a certain viscosity and also
is neavier than the water. I then employ an up
ward flow of wash water through the bed, where
by the bed is kept in a loosened up condition
and whatever- superficial matter or impurities
-may have collected in- the bed is washed out.
switching of beds should be effected substantially
before the “break through” in the last and pre
sumably least exhausted bed occurs. Hence. this
is a matter of determining the limits of permissi
ble exhaustion in relation to the exchange reserve
capacity of the beds, and maintaining the opera
tion substantially within the limits of that re
serve. This will be discussed in further detail in
connection with Figs. 8 and 9.
‘
In this way the bed is conditioned for the re
generation phase proper to be performed effec
.
In the present instance, the average degree of 10 tively, as no residual sugar juice will react with
the regenerant, and no obstructive- superficial
exhaustion of a bed at a certain time is measur
impurities
inthe exchanger material impair its
able in terms of pH of the juice that has been
rate of regeneration proper.
treated in the bed, for the reason that the pH
In the regenerative treatment of the exchanger
indicates the degree of acidification of the juice
as it passes through the cation beds. and also 15 a regenerant solution of suitabletype, strength,
and concentration is used. By conversion in the
the degree of de-acidiilcation as it passes through
exchanger the solution is reduced to a point of
the anion beds. After proper operating rela
concentration corresponding to the intensity of
tions have been established between flow rates of
’
conversion or exchange, and correspondingly-en
the juice. reserve exchange capacity of the beds,
and permissible pH values of the juice treated, 20 riched in salts, as previously explained. Other
collected impurities such as dissolved organic
a routine for effecting the switching and renewal
matter are also removed from the bed incident
of the bedsv may be guided by and established on
to this regeneration, and I have particularly ob
the basis of such relations and values.
served varied degrees of coloring in the spent
In operation. when the first cation bed is work
ing with an adeouate exchange intensity, the juice 25 regenerant liquor, which I have interpreted as
representing color constituents removed from the
leaving that bed will have its pH below a prede
juice by the exchanger. Such coloring was not
ably in evidence in the spent regenerating liquor
termined limit. with still suiiicient reserve ex
change capacity available in the ñrst and the
next following bed or beds.
from the anion beds.
As the first bed be
comes zone-Wise more and more exhausted to
30
wards its outlet end, the reserve exchange ca
Spent regenerating liquor may be utilized for
the values or by-products in it, and previously
referred to.
pacity diminishes, while the pH of the juice
I
The next phase or washing operation removes
treated in _the first bed rises, indicating a lessen
unused or residual regenerant from the bed and
ing in the exchange intensity of that bed. There
fore, when the pH has risen to a predetermined 35 prevents its reaction with juice thereafter fed
to the bed.
value. a switching and renewal of beds should be
In order to sustain the operation of the ex
effected as above indicated, in order to replenish
changer station, it appears that at least one
the reserve exchange capacity of the series for
extra bed is needed in each battery, besides those
another period. Similarly, when the first anion
currently operating, so that a regenerated bed
40
bed is working with an adequate exchange in
may be available for active substitution in the
tensity. the juice leaving the first anion bed will
battery when required.
have its pH above said predetermined limit. with
An exchanger station to be operated for the
still suillcient reserve exchange capacity avail
purposes
of this invention will now be described
able in the first andthe next following bed or
45 in still further detail and in connection with Fig.
beds.
6 of the drawings.
A mode of exchange operation according to
This station is shown to contain a cation ex
the process of this invention lies in the use of
only two active cation beds in series followed
change battery lli, and an anion exchange bat
fied. and likewise tiie operation of only one
anion bed needs to be coordinated to the other.
By avoiding “break through" in the respective
second beds the operation may be carried along
equipment including the evacuator 84 and the
filter 88 shown in Fig. 5, and therefore like parts
o_f this intermediate station are -designated by like
tery H2. |An_equipment station H3 is disposed
by two active anion beds. in series. In that
between
the two batteries for intermediate treat
manner only one cation bed needs to be operated 50
ment of the juice if desired. It corresponds to
in relation to the other, so balancing is- simpli
numerals in Fig. 5 and Fig. 6. However there are
shown in Fig. 6 two additional valves ill and i I5
on the safe side as regards reserve exchange
whereby the entire intermediate treatment sta
capacity.
tion H3 can be cut out, while a third valve lita
ÄRegeneration of exhausted beds may be car
when open permits by-passing the intermediate
ried on simultaneously with the active operation
of the exchanger station. According to the pres 60 station and direct transfer of juice from the cat
ion exchange battery iii to the anion exchange
ent disclosure regeneration operation comprises
battery i i2.
substantially three operating phases, namely dis
The cation exchange battery I | | comprises four
placing a-nd washing out sugar juice and of
units or exchanger beds lll“, iii", iii“, llld. A
superficial impurities from the bed, treating the
bed with the regenerant solution, and displacing
and washing out unused or residual regenerant
from the bed. These operations are so conducted
that the exchange material remains submerged
65
juice supply header ||1 has laterals orbranches
H8, H9, |20, |2I, for selectively> feeding juice
through respective valves |22, |23, |24, |25, to the ‘
exchanger beds III“, Illb, |||°, iild, respectively,
the juice entering the bottom portion of the beds
substantially at all times.
'
I place emphasis. although in no limiting sense. 70 as will be seen. A corresponding juice discharge
header |26, receives treated juice from the re
upon the manner in which I ‘conduct the first of
spective top portion of the exchanger beds as will
these treatment phases, that is the freeing of the
be explained, and for this purpose is provided with
bed of juice and of superficial impurities. That
corresponding laterals or .branches |21, |28, |29,
is to say,`I first displace and wash the juice from
the bed by a downward iiow of wash water there 75 |30, having respective valves |3i, |32, |33, |34,
23>
2,418,844
x
I» ' through which treated `juice may be discharged
24
nection I4|, inlet connection |42, and valve |60
enters the next exchanger bed IIIb. The juice
moves on upwardly through bed III", leaving it
through outlet connection |43, passing down
. i from the beds III", III”, I|I°, IIId, respectively.
` The lateral |30 differs somewhat from the lat
erals |3I, |32, |33, in that it terminates in atrans
verse connection |35 extending between the valves
|34 and | I4. The first bed IIIß has an inlet con
transfer connection I 45, and through inlet con
nection |46 and valve |41 into the last active bed
nection |36 for juice to be treated, which ter
|I |°, leaving it through outlet connection |48 and
minates in a transverse portion |31 which in turn
valve |49. The valve setting as described above
extends between the valve |22 and a, valve |38.
then permits the juice to pass down the transfer
Treated juice leaves the ñrst bed at the top there 10 connection |50 and on down through valve |33
of by way of an outlet connection |39 which
leading into the discharge header I 26 from where
through a. valve |40 leads into a, transfer connec
it may flow either through branch |30, connection
tion I4I extending between the valves |23 and
|35 and valve I I4 into the intermediate treatment
|3| and leading into the next exchanger bed I I Ib
station II3, or else directly through connection
through an inlet connection |42 at the bottom
II6 and valve II 6a into the anion exchanger bat
thereof and by way of valve |60. Again the juice
tery I I2, where it may follow a course through a
leaves this bed II|b at the top through an outlet
series of active beds in a manner similar to the one
connection |43 which by way of a valve |44 leads
just vdescribed for the cation exchanger battery
into a transfer section |45 extending between
I|1.
valves |24 and |32, and in turn leading through 20
If the cation exchanger bed III“ has become
an inlet connection |46l and valve |41 into the
sufllciently exhausted or weakened, it is cut out
bottom portion of the third exchanger bed III”.
of active service by closing the valves |22 and |38
Juice may leave bed ||I° at the top thereof
at the inlet end and valve |40 at the outlet end
through an outlet connection I 48 and valve |49
thereof. The bed IIId which now is assumed to
into a, transfer connection |50 extending be 25 have been regenerated, is placed into service by
tween valves |25 and |33, and by way of an inlet
opening the valves |52y |54, and I 34, and closing
connection I 5| and valve |52 leading into the
valve |29. Valve |23 is then opened and the juice
' bottom portion of the fourth exchanger bed I| Id.
sent sequentially through beds IIIb, III“, and
Juice may leave the bed |IId at the top portion
bed III‘l from which the juice passes out of the
thereof through an outlet connection |53 and 30 cation exchanger battery III through valves |53
valve |54 and pass out of the battery through valve
and |34, and connection |35, either through in
|34.
termediate treatment station ||3 or directly into
Another transfer connection |55 extends> be
the anion exchange battery |I2. Meanwhile bed
tween the valves |38 and a valve I 56 for a. purpose
I I I"L is being regenerated.
to be described.
If next bed III” is taken out of active service,
The juice connection and valves just described
the
beds IIIc, IIId, and IIIa will be established
make it possible to operate the battery in what is
sequentially in active service, with juice entering
herein called a quasi-continuous fashion. That is
ñrst bed l I Ic, then passing through bed I I Id, and
to say, they permit to pass juice for treatmentl in
finally through bed IIIB. In that instance use
series through any three sequentially disposed 40 must be made of the transfer connection |55 for
beds out of the four, while a fourth bed is cut out
bringing the juice from bed II Id at one end of
to be regenerated. For convenience, the beds 1n
the battery to bed III“ at the other end of the
which the juice is being treated will be called the
battery. The valve setting then is such that the
active beds, and the ones that are idle, or are being
juice passes from the supply header ||1 through
regenerated or have been regenerated will be 45
called the inactive beds.
The ratio of active to inactive beds may be
varied, so that for instance only two beds may
be kept active and the other two inactive at a time.
Such practice is adapted to provide at least one 50
inactive although regenerated bed ready for serv
ice while a second inactive bed may be in the
process of regeneration.
However, let us assume that beds IIIB, I I Ib,
IIIc are active, 'While bed | I Id is inactive. Bed
IIId is cut off the juice supply and discharge sys
branch |20, valve |24, transfer connection |45,
inlet connection |46 and valve |41, exchanger
bed III c, outlet connection |48, transfer connec
tion I 50,» inlet connection |5I and valve |52, ex
changer bed IIId, outlet connection |55, valve
|38, connection |31, inlet connection |36, ex
changer bed IIIß, outlet connection |39, valve
|40, transfer connection I 4I, valve I3I, and into
the discharge header |26 from Where it may go
either by Way of branch |30, connection |35, and
a valve |I4 to the intermediate treatment station
tem by closing valves |52 and |53. The juice sup
ply to the active beds indicated at IGI, enters
the supply header I I1 by way of a flow meter |62.
A valve |63 in a branch connection, whereby the 60
ñow meter may be by-passed, is closed. Closed are
’I I 3, or else directly from the discharge header
|26 through connection IIB and valve IISa into
the anion exchange battery I I2. Meanwhile .the
bed I | Ib is being regenerated.
Next in line for active service are the beds I | I d,
III“, and IIIb in that sequence, with bed I||c
taken out of service for regeneration. The juice
will then pass from the supply header II1,
IIIa and the juice discharge valve |33 >after bed
|I|c are open. Closed are the valves |38, |56, 65 through branch |2|, valve |25, transfer connec
tion |50, inlet connection |5| and valve I 52, ex
and |34. The juice is then free to pass from sup
ply header II1 through branch connection |I8,
changer bed IIId, outlet connection |53, valve
valve |22, and connection |31 and |36 into the
|54, connection |51, valve I 56, .transfer connec
bottom portion of the first exchanger bed || Ia.
tion |55, valve |38, connection |31, inlet con
The juice rises through the bed at an ap 70 nection I 36, exchanger bed I | I“, outlet connec
propriate rate of ñow and in a manner to keep the
tion |39, and valve |40, transfer connection |4I,
bed loose without causing in it undue agitation
valve I3I, and into the discharge header |26 lead
or “boiling over” of the exchanger material.
ing either through branch |30 and valve I|4 into
Leaving bed III“ through the outlet connection
the intermediate treatment station II3, or else
'|39 the juice moving down through transfer con 75 through connection ||6 and valve H6'l directly
also the valves |23, |24, |25, and the valves I3I,
|32, but the juice inlet valve |22 ahead of bed
26.
tlrst a down wash whereby sugar juice is dis
into the anion exchange station H2. Meanwhile
placed irom and washed> out of the bed, followed '
by an up wash to eiïect loosening up of the bed
with concurrent washing out or flushing out of
bed I I |° is being regenerated.
From the foregoing it will be seen how the
active exchanger load can be rotated in a cycle
or sequentially through the exchanger beds of a
battery in a manner to establish a quasi-continu
whatever superficial matter or impurities may
have‘accumulated in the bed or on the granules
of the exchanger material thereof.
Thereupon the regeneration phase proper of
' ous operation. Furthermore, an operating routine
on the same principle can be established with
only two beds active, and the two other beds in
active.
A cyclic operation on the principles described
for the cation exchange battery ||| can be prac
ticed similarly with the anion exchange`battery
H2, so that no separate description thereof is
required. For this reason pants of the anion ex 15
change battery ||2 are numbered the same as
nection |86 is closed. The spent regeneration
liquor in that in-stance passes from the bed
through the discharge connections described for
the preceding water wash. namely, by way of
corresponding parts of the battery I I l, except for
-the addition of the distinguishing letter “a” or
“a’ ” respectively.
the bed is entered into by admitting the regen
erant solution from the regenerant header |68
through a branch connection |83, and valve |815,
and through inlet. connection v|39 to the top of
the exchanger bed Ill“, if a downward ilow of
regenerant through the bed is desired, and pro
viding that valve |86 of a subsidiary branch con
.
For the purpose of regenerating the beds of lthe 20 valve |11.
If it is desired to pass the regenerant solution
cation exchange battery ||| there are provided a
upwardly through the bed, the valve |84 is closed
wash supply header |65, herein briefly called .the
and the solution caused to pass through valve
-water header, into which water enters at |66
|85 land the subsidiary branch connection |86 into
through a flow-meter |61, and a supply header
|68 for the regenerant solution, herein briefly 25 the bed |||ß at the bottom thereof, and to rise
'in the bed to the outlet connection |39 from where
called the regenerant header, into which regener
it passes out as spent regeneration liquor through
ant solution enters at |69 by way of a now-meter
the same connections described for the earlier
|10. The anion exchange battery ||2 is provided
upward water wash, that is by way of valve |16.
with similar headers for supplying wash water
and regenerant solution respectively to the beds, 30 The spent regeneration liquor may be utilized with
respect tothe recovery therefrom of values- or
and they are marked |65“ and |68a respectively.
by-products. In the case of beet juice, potassium
Branch connections lead from each of »the two
compound contained in the spent regeneration
supply headers in a battery to each unit or ex
liquor from the cation exchange beds is an ex
changer bed thereof, and their arrangement is
ample of such a value or by-product, and it may
substantially identical for each bed. It will
be returned to the soil whence it came or recov
therefore suffice to describe them in connection
ered by special treatment.
with one bed, for instance bed |||a of ‘the cation
For reasons previously explained, the condition
exchange battery |||.
or degree of weakening or exhaustion of a bed
From the water header |65 a branch connec
rtion |1| leads downwardly and terminates in the 40 in active operation, can be judged by the pH of
the juice treated by it, and the operation then be
inlet connection |36, leads into the bottom por
conducted accordingly. For this reason Fig. 6
tion of bed |||‘. but may be shut off by a valve
discloses what is known as an automatic or con
|12. A subsidiary branch |13 connects the
tinuous pH indicatondisposed at the outlet en_d
branch connection I1| with the top portion of
of a bed. Such a pH indicating device is herein
the bed |||°~ by Way of a valve |14. By closing
shown at the outlet end of each exchanger bed of
the valve |12 and opening valve |14, or vice versa
the cation exchange battery ||| as well as of the
anion exchange battery H2, and designated by
or an upward wash respectively. The spent wash
the numeral |81. An additional one is shown at
liquid accordingly can be discharged from the
bed either at the bottom or at‘ the top thereof. 50 the inlet end of the juice header ||1, as at |88.
Also, the pH value of so treated juice can be
When washing the bed lll“ upwardly the bed is
checked by titration, as against the pH or alka
ñrst cut oiî the juice supply and discharge sys
linity of the incoming juice, and the operating
tem by closing valves |22 and |38 and |40, and
condition thus be gauged. Based on such indi
wash water then allowed to enter through valve
|12 and inlet connection |36 at the bottom por 55 cations the changing or switching of beds in a
battery is undertaken in the manner previously
tion of the bed, then to rise to the outlet connec
tion |39, and to pass out through a connection
The operating principle of a continuous pH in
|15 branching off the outlet- connection |39, pro
dicator can be seen from Fig. '1 where |88a desig
viding a valve |16 therein is open, and valves |11
and |18 are closed. The spent wash liquid will 60 nates thetop portion of an exchanger unit andA
|89 the outlet connection therefrom for treated
rise through the riser pipe |19 and by way of an
juice. A continuous sample stream of juice flows
overñow box and adjustable Weir |80 discharge
from this outlet connection through a pipe |90
into a catch or funnel |8| and run off through
into an overñow or sampling bowl |9|, also called
pipe |82. The point of overflow may be adjusted
lthe exchanger bed Illa can be given a downward
described'.
in a manner to insure submergence of the ex
‘
'
65 electrode bowl, because it carries the test elec- I
changer material of the bed.
When washing the bed |||° downwardly, water
is allowed to enter through valve |13 at the top
portion of the bed, then moving down through
the bed, and passing out at the bottom through 70
trodes |92 and |93. The overflowing juice is
caught in box |94 from where it is pumped back
by pump |95 and through pipe |96 for instance
to the top of the bed from which it came.
The electrodes send a continuous impulse cor
responding to the pH value of the juice to an
indicating instrument herein not shown.
When a bed is being regenerated, and the ñrst
or down wash is applied to remove juice, the com
valve |11, with valves |16 and |18 closed, and
then as before to rise through riser pipe |19,
overñow box |80, to catch |8| for disposal.
In this way, after abed .such as |||l is taken
out of service for regeneration, it can be given 75 pleteness of that wash .can be judged by testing
27
2,418,844
the wash liquid as to its total content ofI dissolved
matter as measured in Brix and determined by
such a manner that fresh exchanger is allowed
to operate as bed C2 or second bed ior a period
refractometer reading. When this content has
of time long enough to consume or substantially
dropped suilicientiy or to substantially zero, the
consume but not substantially to exceed the
second or up wash may be initiated and continued
break-through capacity of the exchanger by acid
until the bed is considered free of such impuri
ifying the juice. During the identical time inter
ties as will be ñushed out by the water.
val the bed> C1 may operate through the range
When regenerant solution is then passed
B-C, and in an ideal case of operation the point
through the bed, the degree of eiiìciency of ex
C of exhaustion of bed C1 or first bed will coin
change or conversion of the regenerant solution 10 cide with the break-through point B of bed C2
can be judged by the relative drop in the concen
or second bed.
tration of the regenerant in the spent regenera
In order to maintain quasi-continuous opera
tion liquor. A relative technical and economical
tion through a continuous chain of operating
optimum o'f operation may be established by the
cycles, bed C2 is kept going approximately until
choice of the concentration apparent in the re 15 the break through point B is reached, when it
generant liquor, acid or alkaline, whichever the
is shifted to displace bed Cz which is removed
case may be, as compared with the reduction in
for regeneration, having reached its lower limit
concentration apparent in the spent regenerating
of exhaustion. A new bed C2 is substituted, and a
liquor.
new cycle is started. In this way the capacity of
When the bed i-s then washed to remove unused 20 one bed is substantially balanced against that of
the other.
‘
or residual regenerant from the bed, an indica
tion of the completeness of this washing opera
In Fig. 9 this cycle is shown in terms of acidifi
tion can be had by determining the relative
cation and de-acidiñcation for the cation beds
and the anion beds respectively. This shows
amount of those dissolved salts in the spent wash
liquid, which were originally found. in the spent 25 that at the beginning of the cycle the major part
‘or substantially al1 of the acidification is effected
regenerating solution. 'I‘itration test will give
in bed C1 according to line (a) of the diagram,
such indication. A more sensitive test is by elec
the subsequent bed C2 substantially not yet being
trio conductivity measurement of the spent wash
used at that time. However, as the exhaustion
liquid. Automatic or continuous conductivity
meters may be provided for this purpose, but are 30 of bed C1 proceeds, the effectiveness or exchange
intensity of bed C1 approaches a condition indi
not -shown in the drawings.
cated by the dotted line (b) and correspondingly
Test cocks I 91 are shown to be provided at vari
more exchange burden is placed upon the next
ous depths of the exchanger bed, to permit test
ing the condition of the beds in various zones ` bed C2, as indicated by the dotted line (c) . Cor
thereof. A conductivity test or continuous con 35 responding conditions may be assumed to exist
in the operation of the anion beds A1 and Az,
ductivity meter numbered |98, if provided. at the _
in which case the full line (d) indicates that sub
treated juice outlet end of the anion battery I l2,
stantially all of the de-acidiñcation is being ef
will provide a; check up by indicating whatever
fected in the bed A1 alone, at the beginning of
trace of dissolved salts might be found in the puri
ñed juice.
l
40 the cycle, while the exchange capacity of bed A2
remains substantially unused. Dotted lines (e)
Vent connections |99 are indicated at the top
and (f) indicate the condition when the burden
of each exchanger bed in Fig. 6.
of exchange is distributed over both beds A1 and
Let us consider the case where the juice is
A2.
l
treated in a series of two cation beds followed
Example
by a series of two anion beds, the treatment be 45
ing conducted on the basis of titration and pH
During the campaign a beet juice which had
determination of the juice treated, and with re
gone through carbonation and sulñtation treat
spect to the exchange characteristic of the ex
ment with subsequent filtration, was obtained in
changer, as represented by the curve in Fig. 8.
approximately the following condition:
Such an arrangement is diagrammatically shown
in Fig. 9 including cation beds C1 and Ca, and
pH: 7.5-8.5
anion beds A1 and A2.
Color: That of the usual carbonated beet juice.
A capacity curve showing the exchange of a
Brix: 12.5-15.0
y
cation exchanger is given in Fig. 8, and the man
Apparent purity: (This juice contained no invert
ner of conducting the-operation in respect to it 55 sugar) 89-90.
will now be discussed.
The diagram in Fig. 8 gives a picture of an eX
changer characteristic, that is the intensity of
Ash analysis: Inorganic impurities (dissolved):
(By furnace test) 0.25-0.30 g./100 g. of thin
Juice.
~
the exchanger in terms of acidiiìeation of the
After cooling to about 20 to 30 degrees, the
juice during cation exchange, as a function of the 60 juice was subjected to treatment in a series of
volume of juice passing through the exchanger.
cation exchange beds containing an organic cat
.From point A to point B the exchange intensity
ion exchange 'material of resinous type. To
stays at an average maximum. The phase A-B
be specific, I have used a cation exchanger
is called the break-through capacity of the ex
furnished me by the Resinous Products Co.
changer, the point B being known as the “break 65 of Philadelphia; under the name or identi
through” point, that is the point at which the
ñcation of Amberlite IR.1 which is a mate
exchange intensity begins to weaken. B--C is
rial of synthetic resinous nature,` and more spe
the range where progressive weakening of the
cifically, a material prepared by the condensa
exchange intensity takes place. At point D the
tion of a dissolved organic chemical of a group
degree of-weakening or exhaustion may be as 70 comprising sulfonated phenols and aromatic
sumed to have reached a point where regenera-V
amines, with an aldehyde. This exchanger was
tion of the exchanger becomes advisable or nec
regenerated with hydrochloric acid of about 5%
essary. In view of suchcharacteristic of the ex
concentration. The cation- exchange rendered
changer, and referring` to Fig. 8, the operation of
the juice acid to a pH of about 1.8 to 2.0 with an
the cation beds C1 and C: may be conducted in 75 acidity of 0.06 normal by titration with 0.5 N
Документ
Категория
Без категории
Просмотров
0
Размер файла
2 908 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа