Cascade units for neon isotopes production by rectification method
Basics of neon separation into isotopes by distillation method at T = 28 K are discussed. The required numbers of transfer units of the top and bottom column sections at different loads are calculated. The experimental characteristics of packed rectification columns are presented and examples of t...
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Bondarenko, V.L. Simonenko, Yu.M. Diachenko, O.V. Matveyev, E.V. 2017-05-30T11:53:57Z 2017-05-30T11:53:57Z 2013 Cascade units for neon isotopes production by rectification method / V.L. Bondarenko, Yu.M. Simonenko, O.V. Diachenko, E.V. Matveyev // Физика низких температур. — 2013. — Т. 39, № 5. — С. 617–622. — Бібліогр.: 9 назв. — англ. 0132-6414 PACS: 51.30.+j https://nasplib.isofts.kiev.ua/handle/123456789/118462 Basics of neon separation into isotopes by distillation method at T = 28 K are discussed. The required numbers of transfer units of the top and bottom column sections at different loads are calculated. The experimental characteristics of packed rectification columns are presented and examples of the cascade outlined. A scheme of cryogenic circuit based on the high-pressure throttle neon cycle with intermediate nitrogen cooling is presented. The necessity and the technical ability to create the driving difference of pressures between columns of various stages demonstrated. en Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України Физика низких температур 9th International Conference on Cryocrystals and Quantum Crystals Cascade units for neon isotopes production by rectification method Article published earlier |
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Cascade units for neon isotopes production by rectification method |
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Cascade units for neon isotopes production by rectification method Bondarenko, V.L. Simonenko, Yu.M. Diachenko, O.V. Matveyev, E.V. 9th International Conference on Cryocrystals and Quantum Crystals |
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Cascade units for neon isotopes production by rectification method |
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Cascade units for neon isotopes production by rectification method |
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Cascade units for neon isotopes production by rectification method |
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Cascade units for neon isotopes production by rectification method |
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cascade units for neon isotopes production by rectification method |
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Bondarenko, V.L. Simonenko, Yu.M. Diachenko, O.V. Matveyev, E.V. |
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Bondarenko, V.L. Simonenko, Yu.M. Diachenko, O.V. Matveyev, E.V. |
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9th International Conference on Cryocrystals and Quantum Crystals |
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9th International Conference on Cryocrystals and Quantum Crystals |
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Физика низких температур |
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Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
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Basics of neon separation into isotopes by distillation method at T = 28 K are discussed. The required numbers
of transfer units of the top and bottom column sections at different loads are calculated. The experimental
characteristics of packed rectification columns are presented and examples of the cascade outlined. A scheme of
cryogenic circuit based on the high-pressure throttle neon cycle with intermediate nitrogen cooling is presented.
The necessity and the technical ability to create the driving difference of pressures between columns of various
stages demonstrated.
|
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0132-6414 |
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https://nasplib.isofts.kiev.ua/handle/123456789/118462 |
| citation_txt |
Cascade units for neon isotopes production by rectification method / V.L. Bondarenko, Yu.M. Simonenko, O.V. Diachenko, E.V. Matveyev // Физика низких температур. — 2013. — Т. 39, № 5. — С. 617–622. — Бібліогр.: 9 назв. — англ. |
| work_keys_str_mv |
AT bondarenkovl cascadeunitsforneonisotopesproductionbyrectificationmethod AT simonenkoyum cascadeunitsforneonisotopesproductionbyrectificationmethod AT diachenkoov cascadeunitsforneonisotopesproductionbyrectificationmethod AT matveyevev cascadeunitsforneonisotopesproductionbyrectificationmethod |
| first_indexed |
2025-11-24T02:23:15Z |
| last_indexed |
2025-11-24T02:23:15Z |
| _version_ |
1850836789937307648 |
| fulltext |
© V.L. Bondarenko, Yu.M. Simonenko, O.V. Diachenko and E.V. Matveyev, 2013
Low Temperature Physics/Fizika Nizkikh Temperatur, 2013, v. 39, No. 5, pp. 617–622
Cascade units for neon isotopes production
by rectification method
V.L. Bondarenko
Moscow Bauman State Technical University, 5, 2-d Baumann Str., Moscow 107005, Russia
Yu.M. Simonenko
Iceblick, Ltd., 29 Pasteur Str., Odessa 65026, Ukraine
O.V. Diachenko and E.V. Matveyev
Odessa National Academy of Food Technologies, V.S. Martynovsky Educational-Scientific Institute of Refrigeration,
Cryotechnologies and Ecoenergy, 1/3 Dvoryanskaya Str., Odessa 65082, Ukraine
E-mail: diachenko-ov@yandex.ua
Received November 23, 2012
Basics of neon separation into isotopes by distillation method at T = 28 K are discussed. The required num-
bers of transfer units of the top and bottom column sections at different loads are calculated. The experimental
characteristics of packed rectification columns are presented and examples of the cascade outlined. A scheme of
cryogenic circuit based on the high-pressure throttle neon cycle with intermediate nitrogen cooling is presented.
The necessity and the technical ability to create the driving difference of pressures between columns of various
stages demonstrated.
PACS: 51.30.+j Thermodynamic properties, equation of state.
Keywords: neon isotopes, rectification, packed rectification columns.
1. Introduction
Nearly one hundred years ago A.J. Thomson has deter-
mined for the first time existence of stable elements iso-
topes
20
Ne and
22
Ne [1].
21
Ne was discovered in the twen-
ties. Neon isotopes are widely used in modern high
technologies.
20
Ne +
22
Ne mixtures are object of research
of the physicists, who study mechanism of photonuclear
reactions. Isotopic anomalies help in disclose secrets of our
planetary system formation. In particular, astronomers
have found out that
22
Ne monoisotope is produced when
some meteorites are heated. At the same time the total con-
tent of
21
Ne and
20
Ne doesn't exceed 1% (nearly two or-
ders lower than in neon extracted from the Earth atmos-
phere). Neon isotopes gas mixture (
20
Ne +
22
Ne) is an
active medium in gyroscopes, the operation of which is
based on Szeemann's effect [2]. They are resistant to the
mechanical influences and have stable scale factor. Besides
navigation, such devices are in demand in different areas
of fundamental research in physics. Very perspective is the
sphere of application of the rarest of the neon isotope
21
Ne.
Physicians believe that its nuclear and physical properties
allow using it as an alternative to
3
Не isotope in magnetic
resonance imaging diagnostics of lungs ventilation.
2. Neon separation into isotopes by rectification method
In 1913 the first mass spectrometer, which was invented
a year earlier, was used for separation of neon isotopes
samples. Separation of
20
Ne and
22
Ne isotope pair for la-
boratory and industrial purposes is also possible by me-
thods of thermal diffusion and chromatography [1,3]. Neon
is at the limit of application of distillation method, which is
considered to be effective at molecular masses less than 20
[4]. Separation coefficient of
20
Ne and
22
Ne isotopes be-
tween liquid and vapor phases in equilibrium at tempera-
tures 27 K 30 KТ is = 1.040–1.032 [5]. Neverthe-
less, the low-temperature rectification is considered to be
the most perspective method of neon separation [6]. This
statement becomes even more powerful, if one of the target
products is
21
Ne.
Let's consider the process of the
20
Ne +
22
Ne binary mix-
ture separation. Illustratively let’s consider у–x diagram
with the reference to the high-boiling isotope. Figure 1(b)
shows that the graph is symmetric to the typical diagram,
mailto:diachenko-ov@yandex.ua
V.L. Bondarenko, Yu.M. Simonenko, O.V. Diachenko and E.V. Matveyev
618 Low Temperature Physics/Fizika Nizkikh Temperatur, 2013, v. 39, No. 5
constructed with the reference to the low boiling compo-
nent of mixture. This fact allows avoiding unnecessary
recalculations of concentration and provides information
on the contents of the target product (
22
Ne) in streams and
sections of the column immediately.
Table 1 shows the results of calculation of the number
of theoretical plates (NTP) for the top and bottom sections
of the column. Isotope concentrations of the streams, ac-
cepted in calculation, are the following:
– initial mixture with х0 = 0.0925 (
22
Ne natural isotope
ratio of 9.25%);
– bottom section of the column product хP = 0.9999;
– waste stream, removed in the upper part of the co-
lumn, хW = 0.015.
At such concentrations of the waste flow W we lose
15% of the target product, and the level of extraction is
С = 0.85, where
0
0
( )
( )
W P
P W
x x x
C
x x x
. (1)
In accordance with the definition of the NTP, it was ac-
cepted that liquid and vapor are in equilibrium at each
elementary rectification stage. In general case the equation
for the upper column operating line is as follows:
( )F
W W
L
y x x x
G
, (2)
where LF and G are the flow rates of liquid (reflux) and of
vapor, mol/s; x is the concentration in liquid phase at the
arbitrary section of the upper column, mol/mol (Fig. 1(a)).
The corresponding equation for the lower column is:
0
0 0
F
i
L L
y x x y
G
. (3)
Fig. 1. Material flows (a) for the top and bottom sections of the column and operating lines (b) in у–x diagram built according to high-
boiling component (arbitrary scale); L0, W and P are, correspondingly, flow rate of supplying isotope mixture, of waste (enriched with
20
Ne) and of target product (
22
Ne).
Table 1. Specifications of operating conditions on the top and bottom sections of the rectification column at the liquid feed by neon
having ―natural‖ concentration of the high-boiling component (x0 = 0.0925) and outflowing streams xW = 0.015 and xp = 0.9999.
E is description of the mode, degree of equilibrium in the stream delivery point; F is angular coefficient of lines in the 0Wx x area;
TN , TN are NTP; 0iy is coordinate of the working lines crossing at 0x x ; F is angular coefficient of lines in the 0 Px x area.
0 0
0 0
D i
D E
y y
E
y y
Top section Bottom section
Total NT,
pieces
F
F
L
G
,TN pieces 0iy 0F
F
L L
G
TN , pieces
No-load. E = 0 1.0 (diagonal) 52.3 y0D = х0 = 0.0925 1.0 316 368
Intermediate
conditions
E = 0.2 0.992 59.8 y02 = 0.0919 1.00066 327 387
E = 0.4 0.984 70.6 y04 = 0.0913 1.00132 340 411
E = 0.6 0.977 88.3 y06 = 0.0907 1.00199 357 445
E = 0.8 0.969 125.6 y08 = 0.0901 1.00265 384 510
Minimal reflux E = 1
0.961
(equilibrium curve)
∞ y0E = 0.0895 1.00331 ∞
Cascade units for neon isotopes production by rectification method
Low Temperature Physics/Fizika Nizkikh Temperatur, 2013, v. 39, No. 5 619
Here L0 and x0 are flow rate and concentration of the vapor
feed stream, mol/s; x is concentration in the liquid phase at
the arbitrary section of the lower column, mol/mol; y0i is
ordinate of the intersection of the top and bottom sections
operating lines of the column (Fig. 1(b)).
In the case when initial mixture is loaded to the column
as a liquid, the ordinate of points y0i, where operating lines
intersect, will be on the vertical line x0 = 0.0925 within the
segment limits 0 0– .D Eу у The calculation model consid-
ers: ―no load‖ mode, corresponding to the absence of se-
lection of the product P = 0 ( 0 0Dу x ); maximal loading
in the case of minimal reflux ( 0Eу ), as well as four inter-
mediate modes: у02, …, у08. The operating lines are spaced
from the diagonal у = x by 20, 40, 60 and 80% of to the
maximal distance, characteristic for the mode of minimum
reflux ( 0Еу ). For the accepted concentrations of streams,
the relative flow rate of the product Р/L0 varies with in-
creasing of the loading from Е = 0 up to Е = 1.0 within the
range of 0–0.0033. Therefore, the volume of the product
having 99.99% isotopic concentration of
22
Ne does not
exceeds one third of a percent from the flow rate of the
supply substance L0.
As our calculations show, the number of theoretical
plates is calculated by hundreds. As the height of the trans-
fer unit for the applied types of the packing makes dozens
of millimeters (see Table 2), a column producing
22
Ne
with isotopic quality of 99.99% and extraction coefficient
С = 0.85 must have a considerable size. The height of the
mass exchange part may reach 15–20 m. Such sizes lead to
a considerable external heat leakage and complicate the
cryogenic support of the unit.
Factor of separation q of column and number of theore-
tical plates NT in the case of no extraction of product
(Р = 0) are specified by the Fenske formula [7]:
1
1
TNWP
W P
xx
q
x x
, (4)
where is separation coefficient of binary system
( = 1.037 for isotope pair
20
Ne–
22
Ne) [5].
3. Separation of neon isotopes in cascade
of rectification columns
If the height of a single column is limited (see Table 2),
it is impossible to obtain the high quality хР of (
22
Ne)
product. For this reason, the separation of isotopic compo-
nents has to be made stage-by-stage. On some stages of
separation the accumulation of
21
Ne isotope contained in
the initial mixture in 0.28% concentration is performed.
Figure 2 outlines schemes of successive concentration
of the high-boiling
22
Ne and intermediate
21
Ne +
22
Ne
isotopic components. Naturally, xW mixtures enriched with
low-boiling
20
Ne are removed from the waste mixture cir-
cuits.
The first scheme (Fig. 2(a)) provides multiple process-
ing of intermediate fractions in the same column [6]. Ob-
viously, the performance of such method is low and to in-
crease it the cascade connection of several columns is
applied (Fig. 2(b)). The feature of the second scheme is the
return of waste fractions xW2 and xW3 to the previous sec-
tions (1 and 2) for reprocessing. For this purpose at each
next step the pressure relative to the previous one is in-
creased: P1 < P2 < P3. Both in the first and the second case
(Figs. 2(a), (b)) the feed of bottom product xPi to the col-
umn for re-separation processes is accompanied by a num-
ber of unproductive processes.
The resulting intermediate fractions xPi must be forced-
ly heated up to ambient temperature, collected in a gas
tanks, compressed, cleaned of impurities, cooled, and then
let in another column (option (b)) or in the same column
(option (a)). Unfortunately, these procedures result in
losses of expensive isotopic components, enriched by the
target products (
21
Ne +
22
Ne).
More perspective, in our opinion, is third option
(Fig. 2(c)), where the valuable products are supplied di-
rectly to the subsequent stages of cascade (xP1 — to the
column 2, xP2 — to the column 3, etc.) in cold state. Thus,
less valuable products, enriched by predominant compo-
nent
20
Ne are supplied to the block 9 for collection, storage
and purification of fraction. The scheme presented in
Fig. 2(с) can function without returning of waste streams.
Table 2. Comparative characteristics of the packed rectification columns, used by authors for neon separation into isotopes (in the
no-load mode: Е = 0). xW and xP are concentrations of the high-boiling component
22
Ne; SP is spiral-prismatic packing; SC is spiral-
cylindrical packing.
Diameter,
mm
xW xР
NTP,
NT, pieces (4)
Height of the theo-
retical plate, mm
q is separation factor (4)
Specific surface area
of packed bed, m
2
/m
3
22 0.003 0.985 275 28.7 21 800 5300–SP
25 0.004 0.983 263 30.0 14 400 5200–SP
25 0.02 0.98 215 30.5 2 400 5000–SP
32 0.06 0.92 150 42.0 180 4000–SC
35 0.05 0.95 160 40.1 360 3500–SC
50 0.01 0.5 130 50.4 100 3500–SP
50 0.015 0.4 105 61.0 45 1900–SC
V.L. Bondarenko, Yu.M. Simonenko, O.V. Diachenko and E.V. Matveyev
620 Low Temperature Physics/Fizika Nizkikh Temperatur, 2013, v. 39, No. 5
In this case xWi fractions are collected and used, e.g., for
preparation of mixtures with modified (different from natu-
ral) isotopic ratio.
For the operation of the circuit shown in Fig. 2(с), the
driving difference of pressure between the stages
P1 > P2 > P3 must be maintained. Such driving pressure
difference can be achieved through the different thermal
loading in vaporizers of bottom section of the column 3
(Fig. 3(a)). An important operating advantage of the scheme,
shown on Figs. 2(b) and 3(a), is the decreased pressure in
the end column III. Thus the coefficient of relative volatili-
ty (separation factor) of the isotope pair
20
Ne +
22
Ne is
increased with reduction of the working pressure [5].
In Figs. 2 and 3 all stages are conventionally shown as
columns of the same diameter. Meantime most cascade
units use circuits with step-by-step decreasing performance
of elements [8]. Decrease of the flow rate х01 > x02 > x03….
allows reducing the time required to achieve the stationary
state in the columns of cascade. For illustration of this
phenomenon we will introduce the special factor — rela-
tive performance of rectification devices:
0 0
1 2 3( )
L L
V k v v v
h
–1
. (5)
Here L0 is the flow rate of the product processed,
norm. dm
3
/h; v1 + v2 + v3 is the total hydraulic volume of
the column, dm
3
, that consists of volumes of packing sec-
tion (1), of condenser (2) and of bottom section of the
column (3), correspondingly (see Figs. 2 and 3); =
= 0.16–0.18 is the filling fraction of volumes 1, 2, 3 by liquid
neon; k = G / L= 1450 is volume of neon, norm. dm
3
, pro-
duced at evaporation of 1 dm
3
of liquid ( G = 0.829 g/dm
3
is density of gaseous neon at Р = 0.1 МPa and Т = 293 K;
L = 1206 g/dm
3
is density of liquid neon).
As it follows from data provided in Ref. 6 and results of
our tests, the size for the primary column of cascade in
the mode of
22
Ne production is 22 = 0.10–0.12.
When the target product
is
21
Ne, the relative flow rate is
decreased up to 21 = 0.014–0.018. Being a nominal index,
factor , at the same time, shows what amount of time
necessary for initial accumulation of target products in
columns. If this factor is not taken into account and there is
no replacement of isotope products in reflux, which fills
the cavities of devices, it is possible to produce only partly
enriched products. Production of concentrated substances
is possible only as a result of accumulation of sufficient
volume of target product in columns (especially end sec-
tions). Minimum time (hours), required for stabilizing of
concentrations, to a first approximation is
01
mх
х
h, (6)
where 01 3 0.5( )m Рх x х is the average concentration of
the target product in the columns of the cascade, mol/mol.
Fig. 2. Options of the multistage separation of isotopic compounds: on the basis of the same rectification column (a); cascade connec-
tion of columns with heating of intermediate fractions, enriched by target products (b); cascade connection of columns with heating of
intermediate fractions, depleted by target products (c). 1 is rectification columns; (I)–(III) is number of the stage; 2 is condenser; 3 is
vaporizer of the bottom section of the column; 4 is heat exchanger; 5 is gasholder; 6 is compressor; 7 is receiver; 8 is adsorber; 9 is
collection, storage and fractions purification block.
Cascade units for neon isotopes production by rectification method
Low Temperature Physics/Fizika Nizkikh Temperatur, 2013, v. 39, No. 5 621
Taking into account empiric values of 22 and contents
of
22
Ne in the initial neon stream having natural composi-
tion (x0 = 0.0925), one gets 22 100 h. Analogically, for
21
Ne (x0 = 0.0028) production the necessary time is
21 > 20 000 h! To reduce this period the deep concentra-
tion (saturation of reflux by target product) is applied
usually only at the end columns of the cascade. The same
result can be achieved by reduction of volume (diameter)
of columns of end cascades and by increase of the initial
section size. According to Eqs. (4) and (5), the initial sec-
tion determines the quality of the target product, supplied
to the separation circuit. In other words, only the high per-
formance at initial stage can provide the operation of low-
capacity output column.
Meantime, practical implementation of this technical
solution doesn’t give the expected result. An attempt to
increase the flow rate in the initial column by increasing
diameter of its section results in the sharp drop of the sepa-
ration factor q (Table 2). The degree of extraction of target
products (1) accumulating in the packing as a reflux, is
decreased. This negative phenomenon can be leveled by
using several small-scale columns forming initial stages of
cascade (Fig. 4(a)). Theoretically, all columns of the cas-
cade must be unified, and their number at all stages must
be gradually decreased [9]. Such reduction will lead to
redistribution of streams between sections. This will, in
turn, affect the inclination of the operating lines expressed
by Eq. (3) (Fig. 4(b)).
Fig. 3. Cryogenic cascade setup maintenance identical to Fig. 2(с). 1–4 are the same as in Fig. 2; 5 is compressor of the neon throttle
cycle cooled by liquid nitrogen.
Fig. 4. Cascade setup (Figs. 2(с) and 3(a)), formed from the same type columns (a) and character of operating lines (b) in у–x diagram
built according to high-boiling component (arbitrary scale).
V.L. Bondarenko, Yu.M. Simonenko, O.V. Diachenko and E.V. Matveyev
622 Low Temperature Physics/Fizika Nizkikh Temperatur, 2013, v. 39, No. 5
The research carried out allows creating the series of
industrial units for production of neon isotopes with con-
centration up to 99.99%.
4. Conclusions
Ukraine is traditionally a leading exporter of rare gases.
Our country produces about a half of the world amount of
high purity neon. Future progress in isotope technologies is
an actual and logical part of the integrated technological
sequence of the light inert gases production from atmos-
pheric air.
Rectification is an effective method of separation of
gases with relatively small molecular weight. However due
to almost identical physical properties of isotope compo-
nents the separation coefficient doesn't exceed 1.040. It
results in a large number of theoretical plates and in consi-
derable column height (> 15 m). Cascade scheme of the
rectification devices assembly makes it possible to reduce
several times vertical dimensions of the unit, as well as
heat leakage and maintenance costs of cryogenic process.
According to the technical solutions presented in this
article, a series of cascade units for Ne separation into iso-
topes was created. Under conditions of the limited availa-
ble height of rectification columns the record results on
21
Ne enrichment are obtained, as well as
20
Ne и
22
Ne with
isotope concentration more than 99.99% were produced.
1. A.I. Brodsky, Stable Isotopes of Light Elements, Success of
Physical Sciences, Edition 2 (1988), Vol. XX, p. 153.
2. V.V. Azarova, Yu.D. Golyaev, G. Dmitriev, M.S. Drozdov,
A.A. Kazakov, A.V. Melnikov, M.M. Nazarenko, V.V. Svirin,
T.I. Soloviova, and T.V. Tikhmenev, in: Optical Gyros and
their Application, NATO, RTO AGARDograph 339, 5 (1999).
3. А.М. Arkharov, I.A. Arkharov, V.L. Bondarenko, Yu.M. Si-
monenko, M.Yu. Savinov, and А.S. Bronshtein, Nontradi-
tional Technologies of Obtaining the Concentrates of the
Isotope of 20Ne, Proc. 8th Intern. Conf. ―Cryogenics–2004‖,
Prague (2004), p. 175.
4. M. Benedikt and T. Pigford, Chemical Technology of
Nuclear Materials, Atomizdat, Moscow (1960).
5. B.M. Andreev, Ya.D. Zelvensky, and S.G. Katalnikov,
Separation of Stable Isotopes by Physics-Chemical Methods,
Energoatomizdat, Moscow (1982).
6. L. Bewilogua, P. Verges, and H. Vinzelberg, (1977), Isoto-
penpraxis, Bd.9: 97.
7. M. Fenske, Industrial & Engineer. Chem. 24, 482 (1932).
8. А.М. Rozen, Theory of Isotope Separation in Columns, Atom-
izdat, Moscow (1960).
9. V.L. Bondarenko and Yu.M. Simonenko, Unit for Separation
of Gas Mixtures in Rectification Columns. Patent № 121753 RF
for utility model. Priority 20.03.2012. Application #2012110459.
Registered in Public register 10.11.2012.
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