Intensification of thoroughly boiling of massecuite by hydrodynamic method
The effectiveness enhancing of sugar production due to the intensification of heat and mass transfer during boiling of massecuite. The results of theoretical and experimental research of workings processes are fixed in basis of hydrodynamic method of strengthening of circulation in vacuum pans of ba...
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irk-123456789-594872014-04-09T03:01:53Z Intensification of thoroughly boiling of massecuite by hydrodynamic method Basok, B.I. Kulinchenko, V.R. Тепло- и массообменные процессы The effectiveness enhancing of sugar production due to the intensification of heat and mass transfer during boiling of massecuite. The results of theoretical and experimental research of workings processes are fixed in basis of hydrodynamic method of strengthening of circulation in vacuum pans of batch-type. The questions of the practical use of this method of intensification are considered. Підвищення ефективності цукрового виробництва пов’язане з інтенсифікацією процесів тепло- і масообміну під час уварювання утфеля. Результати теоретичного і експериментального дослідження робочих процесів покладені в основу гідродинамічного методу підсилення циркуляції у вакуум-апаратах періодичної дії. Розглянуті питання практичного використання цього методу інтенсифікації. Повышение эффективности сахарного производства связано с интенсификацией процессов тепло- и массообмена во время уваривания утфеля. Результаты теоретического и опытного исследования положенные в основу гидродинамического метода усиления циркуляции в вакуум-аппаратах периодического действия. Рассмотрены вопросы практического использования этого метода интенсификации. 2012 Article Intensification of thoroughly boiling of massecuite by hydrodynamic method / B.I. Basok, V.R. Kulinchenko // Промышленная теплотехника. — 2012. — Т. 34, № 4. — С. 20-27. — Бібліогр.: 6 назв. — англ 0204-3602 http://dspace.nbuv.gov.ua/handle/123456789/59487 664.1.05.004.15 en Промышленная теплотехника Інститут технічної теплофізики НАН України |
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Тепло- и массообменные процессы Тепло- и массообменные процессы |
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Тепло- и массообменные процессы Тепло- и массообменные процессы Basok, B.I. Kulinchenko, V.R. Intensification of thoroughly boiling of massecuite by hydrodynamic method Промышленная теплотехника |
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The effectiveness enhancing of sugar production due to the intensification of heat and mass transfer during boiling of massecuite. The results of theoretical and experimental research of workings processes are fixed in basis of hydrodynamic method of strengthening of circulation in vacuum pans of batch-type. The questions of the practical use of this method of intensification are considered. |
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Article |
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Basok, B.I. Kulinchenko, V.R. |
| author_facet |
Basok, B.I. Kulinchenko, V.R. |
| author_sort |
Basok, B.I. |
| title |
Intensification of thoroughly boiling of massecuite by hydrodynamic method |
| title_short |
Intensification of thoroughly boiling of massecuite by hydrodynamic method |
| title_full |
Intensification of thoroughly boiling of massecuite by hydrodynamic method |
| title_fullStr |
Intensification of thoroughly boiling of massecuite by hydrodynamic method |
| title_full_unstemmed |
Intensification of thoroughly boiling of massecuite by hydrodynamic method |
| title_sort |
intensification of thoroughly boiling of massecuite by hydrodynamic method |
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Інститут технічної теплофізики НАН України |
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2012 |
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Тепло- и массообменные процессы |
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http://dspace.nbuv.gov.ua/handle/123456789/59487 |
| citation_txt |
Intensification of thoroughly boiling of massecuite by hydrodynamic method / B.I. Basok, V.R. Kulinchenko // Промышленная теплотехника. — 2012. — Т. 34, № 4. — С. 20-27. — Бібліогр.: 6 назв. — англ |
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Промышленная теплотехника |
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AT basokbi intensificationofthoroughlyboilingofmassecuitebyhydrodynamicmethod AT kulinchenkovr intensificationofthoroughlyboilingofmassecuitebyhydrodynamicmethod |
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2025-07-05T10:41:45Z |
| last_indexed |
2025-07-05T10:41:45Z |
| _version_ |
1836803273086992384 |
| fulltext |
ISSN 0204-3602. Пром. теплотехника, 2012, т. 34, №420
ТЕПЛО- И МАССООБМЕННЫЕ ПРОЦЕССЫ
UDK 664.1.05.004.15
Basok B.I.1, Kulinchenko V.R.2
1Institute of engineering thermophysics NAS Ukraine
2National university of food technology
INTENSIFICATION OF THOROUGHLY BOILING OF MASSECUITE
BY HYDRODYNAMIC METHOD
Повышение эффективности са-
харного производства связано с ин-
тенсификацией процессов тепло- и
массообмена во время уваривания
утфеля. Результаты теоретического
и опытного исследования положен-
ные в основу гидродинамического
метода усиления циркуляции в ваку-
ум-аппаратах периодического дейс-
твия. Рассмотрены вопросы практи-
ческого использования этого метода
интенсификации.
Підвищення ефективності цу-
крового виробництва пов’язане з
інтенсифікацією процесів тепло- і
масообміну під час уварювання ут-
феля. Результати теоретичного і ек-
спериментального дослідження ро-
бочих процесів покладені в осно-
ву гідродинамічного методу підси-
лення циркуляції у вакуум-апаратах
періодичної дії. Розглянуті питання
практичного використання цього
методу інтенсифікації.
The effectiveness enhancing of
sugar production due to the intensifi-
cation of heat and mass transfer during
boiling of massecuite. The results of
theoretical and experimental research
of workings processes are fixed in basis
of hydrodynamic method of streng-
thening of circulation in vacuum pans
of batch-type. The questions of the
practical use of this method of intensifi-
cation are considered.
G – the expense, kg/h; t/h;
K – coefficient heat transfer, W/(m2∙K);
α2 – coefficient heat payment, W/(m2∙K);
ε – the expense vapor insufflations, %;
τ – the time, h; min.
Index:
ц – cycle to boil thoroughly;
вд – insufflations.
Devices are developed for hydrodynamic
intensification of processes heat and mass-transfer
in vacuum pans it is differentiated mass-transfer
the methods of tricking into, distributing and
mixing of the pumped solution or insufflations of
pair in a vehicle. The simplest device is a circular
tubular distributor with a radius, even the half of
radius of vehicle. It is set between a bottom and
warming chamber of vehicle and has openings
for mixing of pair, insufflations, whether union
couplings for the stream tricking into of pair in
boil thoroughly product. On occasion distributive
a collector took a place from outside a vehicle, and
the union couplings for the stream tricking into of
pair passed through the bottom of vehicle.
Such devices have the substantial failings,
related to the uneven distributing of pair or gas,
which is blown in boiling tubes, which are above
the union couplings or openings of bubbler for
tricking into of pair which is blown. Charges last
will be considerably higher in certain tubes, than in
nearby. To some tubes a pair which is blown will
not get quite. It creates unevenness in maintenance
of pair (gas) and speeds of circulation of product
in a vehicle. In those tubes, where a pair will not
get, speed of circulation of product can diminish
comparably with those values which were got
without insufflations of pair. Especially unfavorable
will be terms heat- and to mass-transfer in those
tubes, where speed of circulation of product will
diminish to the zero or directed in an opposite side.
For heat-sensible products such modes of opera-
tions of boiling pipes are impermissible, because
they are accompanied the protracted stay of pro-
duct in the conditions of considerable overheat
and, as a result, his considerable disintegration.
New method of hydrodynamic intensification
of thoroughly of boiling massecuite by insufflations
of pair or gas inward every for boiling tube, the
resulted in works [1–4] consists in the following:
insufflations of gas or pair is carried out streams
with such speed which allows to desperate pair
(gas), good to mix up it with massecuite and, if
not fully to eliminate, carry the area of existence
of shell-piston form of flow nearer to the exit
from a boiling tube; the expense of pair (to gas)
ISSN 0204-3602. Пром. теплотехника, 2012, т. 34, №4 21
ТЕПЛО- И МАССООБМЕННЫЕ ПРОЦЕССЫ
which is blown is supported in optimum values on
every stage of to boil thoroughly; in a distributive
chamber, considerably anymore pressure of pair (to
gas) of, what is supported blown, than in vacuum
pan, that pressure fluctuations in for boiling tubes
substantially did not influence on an equitability
pair (to gas) which is blown; a distributive device is
executed so that not to create additional hydraulic
supports massecuite which circulates, and stagnant
areas; direction of streams of pair (to gas) is carried
out so that an injection action created greater
additional motive pressure as possible.
For realization of these method two con-
structions of device are developed with a distri-
butive chamber and distributive collector. On
fig. 1 a device is resulted for the hydrodynamic
strengthening of circulation in vacuum pans with
a distributive chamber, which has a transversal
cut, identical to the cut of warming chambers.
Lower ends of for boiling tubes are continuation
of pipes of distributive chamber, in them openings
are executed under the corner of 15…30° to the
ax of for boiling tubes. Through these openings
pair (gas) which is blown acts from a distributive
chamber inward for boiling tubes.
Device for the hydrodynamic strengthening
of circulation in vacuum pans with a distributive
collector which is executed from pipes, for boiling
tubes laid between rows very close to the lower
pipe grate, it is resulted on fig. 2. In a collector
there are sprayers with openings for insufflations
of pair (to gas) inward every for boiling tube. An
angle of slope of ax of openings is 15…30° to the
ax of for boiling tubes. The diameters of openings
in both devices execute small (0,8…1,0 mm). At
the thickness of wall of for boiling tube or sprayer
2…3 mm such openings is short union couplings
or snuffled, that form narrow the stream of steam
(to gas) which is blown is directed.
For support in a distributive chamber or
collector of considerably anymore pressure, than
in vacuum pan, not enough to utilize the pair (gas)
of the proper pressure only. It is also necessary for
this purpose, that total area for insufflations was
the cut of all of openings far fewer area to the cut
of ducting’s for which a pair (gas) is tricked into
to them, that hydraulic resistance of openings for
Fig. 1. A device is for the hydrodynamic
strengthening of circulation: 1– corps; 2 – is a
warming chamber; 3 – is a chamber distributor;
4 – is entrance of pair which is blown; 5 – are
for boiling of tubes; 6 are lower ends for boiling
tubes; 7 – are openings for insufflation of pair.
Fig. 2. A device is for the hydrodynamic
strengthening of circulation: 1 – corps; 2 – is a
warming chamber; 3 – chambers-distributor;
4 – is entrance of the blown pair; 5 – are for
boiling tubes; 6 – is a sprayer;
7 – are openings for insufflation of pair.
insufflations was more high of resistance of pair
(to gas) of highway of tricking into.
Such implementation of devices for the
hydrodynamic strengthening of circulation allows
ISSN 0204-3602. Пром. теплотехника, 2012, т. 34, №422
ТЕПЛО- И МАССООБМЕННЫЕ ПРОЦЕССЫ
to utilize potential energy of pressure of pair (to gas)
which is blown, for creation of additional motive
pressure. The useful overfill of pressure of pair (to
gas) is not outlaid on overcoming of resistances
after length of highway of serve, but grows into
kinetic energy of streams and at mixing passed to
circulatory massecuite. Thus arrived at more even
distributing of pair (to gas) between for boiling
tubes, and also even circulation of massecuite in a
warming chamber. At insufflations of pair (to gas)
thin streams with high speed is his more complete
dispergating and mixing with massecuite which
reduces relative speed of pair (to gas) and promotes
actual vapor keeping (gas keeping of contents) in
for boiling tubes, and also diminishes possibility of
formation of shell-piston form of flow of mixture.
All of these features of the examined method and
will build on for the hydrodynamic strengthening
circulations in vacuum pans of extension his
efficiency.
The hydrodynamic method of strengthening of
circulation does not impose the special limits on the
construction of vacuum pans, unlike mechanical
method. Yes, mechanical circulators can be set
in vehicles only with a central circulation pipe,
while devices for insufflations of pair (to gas) it
is possible to set also in vehicles with an external
circular circulation channel or with two – central
and external the circulation ducting’s which are
executed in modern vacuum pans in connection
with a considerable increase them single power.
In addition, mechanical circulators create the
considerable unevenness of circulation of mas-
secuite in vacuum pans with circular warming
elements, while devices with the hydrodynamic
strengthening of circulation can successfully work
in such vacuum pans. Although vacuum pans
with circular warming elements for today is used
extremely rarely, their use is not eliminated in
the future, as their surfaces of heating have low
hydraulic resistance comparatively.
Experimental information about influence of
structural features of vacuum pans on efficiency
of hydrodynamic method of strengthening of
circulation of massecuite not enough. More
perfect mechanism of operating on circulation
of massecuite and imperfection of devices for
insufflations of pair (to gas) not instrumental in
wide distribution of this method. The production
tests of hydrodynamic method of strengthening of
circulation were conducted with the use of existent
vacuum pans of batch-type [1 – 3]. Found out
more considerable intensity of circulation of mas-
secuite in vacuum pan і with the suspended
warming chamber. One of such vehicles by the
capacity of 6 t massecuite and with the area of
surface of heating of 31 m2 was equipped a device
for the injection of pair under warming a chamber
through eight openings, placed above the bottom
of vehicle in the distance, to the even half of radius
of vehicle from his ax.
Vakuum-pan of G4-PVA-40 (fig. 3) for
strengthening of circulation has a chamber device
(fig. 4). A vehicle had a diameter 3774 mm, height
7440 mm, warming a chamber with the area of
surface of heating of 200 m2, diameter 3350 mm,
by the number of for boiling tubes 513 diameter
102 mm and long 1100 mm.
Additional insufflations of pair (to gas)
violates balance of motive powers and forces of
resistance of, which was folded during natural
circulation, and results in the increase of both
forces, only in a different degree. Obviously,
effective a hydrodynamic method will be in case
that at insufflations of pair (to gas) motive pressure
will grow in a greater degree, than losses of
pressure, related to supports. The first researches
of this method rotined already, that the increase of
expense of pair (to gas) of,що was blown, results in
strengthening circulation and increase of efficiency
heat- and to mass-transfer only to the defined
optimum values. So at insufflations intensification
of heat exchange is arrived at only at low thermal
streams in a warming chamber. At higher pressure
of warming pair and, consequently, enhance able
thermal streams of insufflations practically did not
influence on intensity of heat exchange, opposite,
even worsened it.
Systematic researches of influence of insuf-
flations of air on intensity of heat exchange at
boiling of water and saccharine solutions rotined
that mechanism of intensification of heat exchange
into a for boiling tube at evaporation of water and
saccharine solutions identical. At the increase
ISSN 0204-3602. Пром. теплотехника, 2012, т. 34, №4 23
ТЕПЛО- И МАССООБМЕННЫЕ ПРОЦЕССЫ
Fig. 3. Vacuum pan G4-PVА-40 the
reinforcement of circulation: 1– corpus;
2 – superficies of that enhancer;
3 – insufflations of vapor; 4 – for boiling
tubes; 5 – distributive object.
Fig. 4. Device for strengthening of circulation
in chamber implementation for the vehicle
of G4-PVA-40.
of expense of air which is blown, the coefficient
of heat emission grows, but only to the certain
optimum expense which is 4…6 % from an expense
warming of pair. Increase of expense of air which is
blown, over optimum values result in diminishing
of coefficient of heat emission and pulsating mode
in a boiling tube. The coefficient of heat emission
at insufflations of air for water rises to 10 %, for
saccharine solutions – to 15…20 %. With the
increase of concentration of saccharine solution
efficiency of insufflations grows.
Intensification of heat exchange at insufflations
of air takes a place mainly on the initial area of
tube which is explained falling of piezometer
level of liquid and, consequently, diminishing
of hydrostatical pressure, and also increase
of turbulence of stream. On the initial area of
for boiling tube there was a decline of α2 to the
values more low, than without insufflations. It is
explained high maintenance of pair in mixture,
that drove to the separate moments to drying out
of liquid tape on some areas of tube. Insufflations
of pair or air carried out in a for boiling tube long
5 m codes pithily effervescence of solutions of
glycerin which is on 3 m codes higher than surface
of heating. Thus there was an increase of speed of
circulation, and intensity of heat exchange grew on
200…300 %. Thus, the height of level of product
influences on efficiency of hydrodynamic method
of intensification of for boil thoroughly, at what
with growth of level efficiency of method rises.
No less important is also a question about
dispersion of pair (to gas) that is blown. Searches
of ways of intensification heat- and turbulizations
over of streams of massecuite are unavoidable
brought to the necessity mass-transfer. Bubbles
which are entered in a liquid create plenty of
whirlwinds of, which is instrumental in the increase
of intensity heat- and to mass-transfer. The use of
barbotage allowed to create a new high-efficiency
equipment – air-lift reactors, vehicles with a foamy
contact, reactors with gas-liquid pseudo fluidizing
of particulate matters and others like that.
The source of with-phase turbulence in the
gas-liquid systems [5] is an origin of whirlwinds
of, which is generated instability of free or with-
phase interphase. With-phase turbulence arises
up, if the rates of movement of phases differ on
a size and direction. Viscosity of force of liquid
cause breaking the action of opposite streamlines
gas. Thus there is a rotation of layers of streams
and interphase with the subsequent passing to
the whirlwinds. Intensity of braking of stream is
ISSN 0204-3602. Пром. теплотехника, 2012, т. 34, №424
ТЕПЛО- И МАССООБМЕННЫЕ ПРОЦЕССЫ
proportional energy of basic indignations. Thus,
a friction between the streams of gas and liquid
results in a volume, that the boundary layers of
gas and liquid are pierced whirlwinds which under
the action of force Joukovsky get to the depth of
gas and liquid streams and intensity of the vertical
field is, strengthened those.
Due to formation xopok the surface of phase
contact grows in unit of volume. The hydrodyna-
mic system of gas-liquid emulsion which arises
up here is the mobile system of gas-liquid
whirlwinds. They arise up in the volume of liquid
as a result of collision of bubbles and streamed
gas that move with high speed. The collision of
bubbles and filling gas of liquid is conditioned
kinetic energy of gas, that is why at high-rate
enough of gas all of liquid grows into gas-liquid
emulsion in which on forward motion of gas
whir is are imposed. These factors provide the
considerable increase of intensity of processes
heat- and to mass-transfer.
With the increase of viscidity of liquid
considerable kinetic energy of gas is needed for
the receipt of gas-liquid emulsion. In addition,
at motion along for boiling tubes the structure of
flow tests a change as a result of viscid dissipation
of energy of whirlwinds. However impossible
it is to ignore possibility of intensification of
to boil thoroughly of massecuite due to rev-up
insufflations of pair (to gas) and creation of vapor
(gas) of - massecuite emulsion even on the initial
areas of for boiling tubes. Greater efficiency of
heat exchange is arrived at the low charges of air
which is blown as thin streams with high speed.
Resistance of mass-transfer which tests
molecule of saccharose in transition from surroun-
ding solution in the grate of crystal is examined
as a sum of resistance of tricking into of mass to
the crystal (diffusive constituent) and resistance
of reaction of transition (reactionary constituent).
Diffusive resistance is proportional the thickness
of diffusive layer of the impoverished solution
which surrounds a crystal, and back proportional
the coefficient of diffusion of saccharose in solu-
tion. Diffusive resistance depends on a tempera-
ture, viscidity of solution, and also from the relative
rate of movement of crystals in interpure solution.
Interfusion substantially influences on diffu-
sive resistance. The bubbles of air which is blown
are saturated aquatic pair, except for an especially
hydrodynamic effect which operates on massecuite
as a result of change of closeness of mixture in
the lifting’s ducting’s, take part in transference of
impulses on separate crystals, which acquire thus
relative motion in interpure solution [6].
At the permanent sizes of circulation
contour intensity of crystallization of saccharose
considerably grows with the increase of length of
area, on which interfusion of massecuite was by
air which is blown. At the same time the increase
of height of circulation contour at other permanent
parameters resulted in the decline of efficiency
of action of insufflations of air. The increase of
diameter of tube also resulted in the decline of in-
tensification of mass-transfer at insufflations of air.
The tests of vacuum pans are conducted with
increased a hydrodynamic method rotined [2, 3,
6] circulation of massecuite, that intensity of heat
exchange at insufflations of pair grew on an end
to boil thoroughly massecuite. On fig. 5 the ty-
pical graphic arts of change of coefficient of heat-
transfer are presented K at all stages of cycle. The
sizes of coefficient of heat-transfer test conside-
rable changes both in experiments without
insufflations and with insufflations of pair. Maxi-
mal values K at the beginning of to boil thoroughly
and intermediate values of spades K answer the
terms of to boil thoroughly of liquid products after
the duty pumpings in vehicles. Minimum value K
answers to boil thoroughly of products, to certain
thickening, before the duty pumping. In an initial
period of to boil thoroughly intensification of heat
exchange due to insufflations of pair had irregular
character. It can be explained that boiling of liquid
products at high enough on the initial stage ther-
mal streams and low levels in to boil thoroughly
mass is carried out in the optimum mode of
operations of for boiling tubes, when there is the
developed boiling on all of their length. In these
terms of insufflations of additional pair ineffective.
mass-transfer with-phase to boil thoroughly mas-
secuite boiling vacuum pans for boiling
Far higher efficiency of intensification of heat
exchange is on the finishing’s stages of boiling.
ISSN 0204-3602. Пром. теплотехника, 2012, т. 34, №4 25
ТЕПЛО- И МАССООБМЕННЫЕ ПРОЦЕССЫ
Attached to boil thoroughly of the finished goods
of value K is on the last stages at insufflations of
pair considerably higher than without insufflations.
With the increase of expense of pair which is
blown, value K grew, though not in an identical
degree. Yes, over 120 kg/h did not bring an
increase over of expense to the increase intensity
of K. Attached to insufflations of pair there were
higher amplitudes of vibrations of values K, than at
to boil thoroughly without insufflations. Possibly,
at insufflations of pumping of fresh treacle quick
interfuse with massecuite in a vehicle, reducing his
concentration and viscidity which brings intensities
over of heat-transfer to greater growth, while
without insufflations such interfusion is protracted
or carries local character.
On fig. 6 the graphic arts of change of mass
of crystals of G and mass speed of crystallization
of dG/dτ are resulted on the different stages of
to boil thoroughly. The crooked growths of mass
maintenance of crystals have S-similar kind. Slow
growth of mass of crystals in an initial period is
explained small sizes and, consequently, by the
Fig. 5. A change of coefficients of heat-transfer
is at to boil thoroughly of massecuite: a – are
II crystallizations; b – are III crystallizations of
sugar-beet production; c – IV crystallizations at
processing of cane-sugar-raw; 1 – Gвд = 0 kg/h;
2 – Gвд = 80 kg/h; 3 – Gвд = 120 kg/h.
Fig. 6. Change of maintenance of crystals and
speed crystallizations are at to boil thoroughly of
massecuite: a – II crystallizations:
1 – Gвд = 0 kg/h., τφ = 305 min; 2 – Gвд = 180 kg/h.,
τц =225 min; b – III crystallizations beet
production: 1 – Gвд = 0 kg/h., τц = 735 min;
2 – Gвд = 80 kg/h., τц =448 min; 3 – Gвд = 120 kg/h,
τц = 390 min; 4 – Gвд = 180 kg/h., τц = 320 min.
small surface of crystallization. In this period often
a heat exchange passes ahead mass-transfer which
can result in second crystal-formation. Terms for
a heat exchange on this stage more favorable, than
terms are for crystallization. A level of product is in
a vehicle, the amount of crystals and their sizes is
small, mass is mobile enough, for boiling tubes work
in optimum terms with the maximal coefficients of
heat-transfer. It is thus possible to support maxi-
mal satieties and speeds of crystallization.
The small sizes of crystals and considerable
distances do not allow between them to conduct
intensive crystallization on the led crystals. At
small sizes and relative speed of growth of crystals
in interpure solution is insignificant. In such terms
more frequent all there is second crystal-formation.
That it did not take a place, recommended on
10...15 min. after introduction of crystals to halt
the serve of warming pair.
ISSN 0204-3602. Пром. теплотехника, 2012, т. 34, №426
ТЕПЛО- И МАССООБМЕННЫЕ ПРОЦЕССЫ
Comparisons crooked (see fig. 6) of mass
growth of crystals in massecuite, cooked with
insufflations of pair and without it, shows that in
first case intensity of crystallization is considerably
more high in an initial period. As intensity of heat
exchange in this period rose insignificantly, it is
possible to assume that the increase of intensity of
mass crystallization is conditioned direct influence
of steam streams and bubbles on formation of
crystals in massecuite.
The increase of intensity of mass growth of
crystals is conditioned the increase of efficiency of
recrystal at insufflations of pair in vacuum pans.
At fluctuation in a temperature and satiety in the
volume of massecuite with certain amplitude and
frequency factious composition of crystals in it
tests considerable changes. Thus large crystals
grow quick than at permanent satiety as a result
of partial or complete dissolution of shallow
crystals. During mass crystallization molecular
mass-transfer appears in less degree, and growth
of large crystals is carried out by building in
their crystalline grates to the embryonic clots of
molecules of matter which is crystallizable. It is
carried out in the places of sharp growth of satiety
[6].
Speed of mass crystallization in the middle
of boiling grows at τ/τφ = 0,5…0,8 has maximal
values (see fig. 6). It is caused a jumbo zing crystals
of their surface. Thus distance diminishes between
crystals, less than is become by the thickness of
diffusive layer of solution on-the-spot crystals.
Process of mass-transfer on this stage of to boil
thoroughly limited to nothing. At the same time as
a result of growth of mass maintenance of crystals
and accumulation of no sugar in interpure solution
viscidity of massecuite grows sharply. It results in
the substantial decline of intensity of heat exchange.
High speed of mass crystallization is observed,
when processes heat- and it is flowed mass-transfer
with the proper intensity. The maximal values of
speeds of mass crystallization at to boil thoroughly
with insufflations of pair move nearer to the end of
to boil thoroughly.
On the finishing stage of to boil thoroughly
considerable intensification of process of crystal-
lization is arrived at by insufflations of pair in for
boiling tubes, that conditioned by considerable
intensification of heat exchange. At natural
circulation of massecuite intensity of heat exchan-
ge on this stage sharply goes down as a result
of increase of level of massecuite in a vehicle,
growth of concentration of crystals and increase
of viscidity. Often boiling of massecuite in war-
ming tubes is halted, massecuite here overheats
only, and effervescence of it takes a place in a
volume above the surface of heating. At insuf-
flations of pair boiling is carried in warming tubes.
Speed of circulation and mass crystallization of
massecuite grows.
Conclusions
1. The expense of pair or gas for hydrodynamic
intensification of to boil thoroughly of massecuite
must not exceed ε = 10…15 % from an expense
warming of pair. Values of ε, got at to boil
thoroughly of saccharine solutions, are 4…6 %.
Thus a for boiling tube worked in the optimum
mode at the levels of boiling solution to 40 %
from length of tube. In these terms of increase of
ε to 15 % accompanied strengthening of pressure
and rates of movement of mixture fluctuations in
a for boiling tube with the extras of solution in
a separator, and at ε = 25 % the coefficients of
heat exchange went down so much. Therefore in
vacuum pans with the hydrodynamic strengthe-
ning of circulation it is impossible to assume the
charges of the blown pair (to gas) higher than
optimum values.
2. The optimum charges of air or pair which
is blown in a for boiling tube above the warming
surface of evaporator with the taken away area
of boiling made ~5 % from the amount of the
evaporated water. Thus with the increase of useful
difference of temperatures the optimum values of
ε grow.
LITERATURE
1. Гаряжа В.Т., Артюхов Ю.Г., Кулинченко
В.Р. Вакуум-апарат с усиленной циркуляци-
ей.– Химическое и нефтяное машиностроение,
1976, №4.– С. 3 –5.
2. Вакуум-апарат А2-ПВУ-40 // Гаряжа В.Т.,
ISSN 0204-3602. Пром. теплотехника, 2012, т. 34, №4 27
ТЕПЛО- И МАССООБМЕННЫЕ ПРОЦЕССЫ
Кулинченко В.Р., Артюхов Ю.Г. и др. – Сахар-
ная промышленность, 1977, №12.– С. 27 –30.
3. Интенсификация процесса уваривания
утфелей в вакуум-аппаратах // Гаряжа В.Т., Ар-
тюхов Ю.Г., Павелко В.И., Кулинченко В.Р., и
др. – Сахарная промышленность, 1975, № 1.–
С. 14 –17.
4. А. с. 560623 (СССР)// Гаряжа В.Т., Артю-
хов Ю.Г., Сторчеус М.П., Кулинченко В.Р.– Б.
И. 1977, № 21.
5. Кафаров В.В. Основы массопередачи.– М.:
Высшая школа, 1972.– 655 с.
6. Интенсификация процесса уваривания
утфелей // Гаряжа В.Т., Кулинченко В.Р., Артю-
хов Ю.Г., Дидушко Б.Г.– М.: Легкая и пищевая
пром-сть, 1981.– 152 с.
Получено 14.06.2012 г.
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