CC BY
84 3 2 1
I(A)
U (V)
10
15
20
25
Figure 3. Volt-ampere characteristics of a single crystal silicon-based solar panel.
In the experiment, the short-circuit current of the solar panel was 4.5A, the rated ignition voltage was 22.18 V, the current at the maximum power point was 4.2A and the voltage was 16.9 V, and the fill factor was 0.71. The experiment was conducted at 13:00. Due to the fact that the time of the experiment coincided with the winter, its current was lower. In winter, the intensity of sunlight in Uzbekistan is low.
References
1. Aliev, R., Abduvoxidov, M., Mirzaalimov, N., and Gulomov., J. (2020). Kremniy asosli quyosh ele-mentlarida rekombinatsiya va generatsiya jarayoni. Science and Education, 1(2), 230-235. doi: 10.24412/2181-0842-2020-2-230-235
2. Gulomov, J., Aliev, R., Nasirov, M., and Ziyoitdinov, J. (2020). Modeling metal nanoparticles influence to properties of silicon solar cells, Int. J. of Adv. Res. 8(Nov), 336-345; doi.org/10.21474/IJAR01/12015
3. Gulomov, J., Aliev, R., Abduvoxidov, M., Mirzaalimov, A., Mirzaalimov, N. (2020). Exploring optical properties of solar cells by programming and modeling. Global Journal of Engineering and Technology Advances, 5(1), 032-038; doi.org/10.30574/gjeta.2020.5.1.0080
4. Aliev, R., Gulomov, J., Abduvohidov, M. et al. (2020) Stimulation of Photoactive Absorption of
Sunlight in Thin Layers of Silicon Structures by Metal Nanoparticles. Appl. Sol. Energy 56, 364-370; https://doi.org/10.3103/S0003701X20050035
5. Gulomov, J., Aliev, R., Mirzaalimov, A., Mirzaalimov, N., Kakhkhorov, J., Rashidov, B., & Temi-rov, S. (2021). Studying the Effect of Light Incidence Angle on Photoelectric Parameters of Solar Cells by Simulation. International Journal of Renewable Energy Development, 10(4), 731-736. https://doi.org/10.14710/ijred.2021.36277
6. Гуломов, Д., Алиев, Р., Мирзаалимов, А., Абдувохидов, М., Мирзаалимов, Н., Каххоров, Ж., ... & Иззатиллаев, Х. (2021). Oddiy va nanozarracha kiritilgan kremniy asosli quyosh elementining fotoelektrik parametrlarini yorug'likning tushish bur-chagiga bog'liqligi. Общество и инновации, 2(1), 1222.
7. Aliev, R., Abduvohidov, M., & Gulomov, J. (2020). Simulation of temperatures influence to photoelectric properties of silicon solar cells. Physics & Astronomy International Journal, 4(5), 177-180.
8. Gulomov, J., Aliev, R., Abduvoxidov, M., Mirzaalimov, A., Mirzaalimov, N., & Rashidov, B. (2020). Mathematical model of a rotary 3D format photo electric energy device. World Journal of Advanced Research and Reviews, 8(2), 164-172.
COMPARATIVE ANALYSIS OF THE INFLUENCE OF THE SURFACE TENSION ON THE EFFICIENCY BY RECTIFICATION IN PRESENCE OF DEFOAMING AGENT SIHA SILICONE SE
Karaivanova M.
Assistant dr. University "Prof.D-r Asen Zlatarov" Bourgas, 8000, "Ykimov" Str.1
5
0
0
5
Abstract
Foam formation is unavoidable part in various technological processes. The extensive formation of foam might cause serious problems so special additives are used called "defoaming agents" or "defoamers" to subdue the formation of foam or eliminate the foam formed.
The aim of the present work is to study experimentally the influence of the anti-foam agent SIHA Silicone SE on the height of the gas-liquid layer, the change of the surface tension and, respectively, the degree of separation by the rectification of binary mixture methyl alcohol - water in laboratory column with one sieve plate.
As a result from the experimental and calculation procedures carried out, it was found that the presence of anti-foam agent gives decrease of the foam height 2 - 2.5 times while the values of the local efficiency are by 10% lower. This certainly confirms the fact that the lower foam height, i.e. the smaller interphase results in lower
separation efficiency. Besides, it was found that in presence of defoamer, the values of the local efficiency decrease (from 87,3% to 84,65%) with the increase of the M-index. Thus, it can be assumed that the surface tension does not exert significant effect on the degree of separation.
Keywords: rectification, surface tension, defoaming agent, local efficiency
Rectification is one of the most widely spread methods for separation of liquid homogeneous multi-component mixtures. In broad interpretation, it involves partial evaporation of an individual mixture followed by condensation of the vapor obtained, carried out repeatedly in various types of rectification columns. A characteristic of the operation of these columns is the formation of stable foam which might cause ineffective performance of the column. The control and regulation of the foam is a key issue for producers in many industries and this is why special additives called "defoaming agents" or "defoamers" are used to subdue the formation of foam or eliminate the already formed one. [1,2,3]
By the rectification of some mixtures (e.g. of so called positive mixtures where, according to Zuiderweg and Harmens [4], the easily volatile component of the mixture has lower value of the surface tension compared to the hardly volatile one, i.e. ^ 0), the foam height observed is quite high (developed interphase area) and the use of defoamer in the initial mixture affects the separation efficiency.
The aim of the present work was to study the influence of the defoamer on the height of the gas-liquid layer, the change of the surface tension and, hence, the degree of separation by rectification. For this purpose, experiments were carried out in a laboratory glass column with one sieve plate with mixture of methyl alcohol - water in presence and absence of defoaming agent at the same concentration of the volatile component in the initial mixture.
The experimental studies of the model mixture methyl alcohol - water in preence and absence of defoamer were carried out in laboratory glass column with one sieve plate [5]
For these experiments, defoaming agent SIHA Silicone SE was used. This defoamer is a white liquid emulsion containing poly-dimethylsiloxane (alpha-oc-tadecyl-omega-hydroxy-polyglycol-ether) with chemical name: Octadecan-1-ol, ethoxylated. The criterion
for the choice of defoamer was made with respect to safety (should be non-flammable and should not contain hazardous substances) and taking into account the action mechanisms of silicon defoamers [6].
On the basis of the experimental data obtained, the local efficiency was calculated by the formula [7]:
E =
eog
(yn - yn-i ) (y * -yn-x)
(1)
yn, yn-i - average composition of the vapor flows outgoing and incoming at the nth plate, respectivly
y* - composition of the vapor in equilibrium with the liquid with composition Xn going out of the plate
To estimate the effect of surface tension of the local efficiency (Eog), stabilization index was selected called M-index. It is the product of the process driving force for the liquid phase and the gradient of the surface tension for the composition of the liquid phase. It is calculated by the formula [8] :
M ■■
i *\Aa -(x - x I— v ' Ax
(2)
x - concentration of the volatile component in the mixture, mol/mol
x* - equilibrium concentration Aa/ At - change of the surface tension by the change of volatile component content in the liquid phase
Fig. 1 shows the experimental data for the height of the gas-liquid layer as function of the content of the volatile components. As can be seen from the figure, the foam height varied in the interval form 24 to 50 mm in presence of defoamer while, at the same concentrations but without defoamer, foam height varied from 30 to 80 mm. it mans that the presence of defoamer significantly decreased the foam height at comparatively the same vapor velocity.
Fig. 1. Dependence offoam height on the composition of the binary mixture methyl alcohol - water with and without defoaming agent in column cube xw and the velocity of the vapor in the column (wn)
a w = 0.14-0.15 m/s with defoaming
♦ w = 0.17-0.18 m/s with defoaming
■ w = 0.17-0.18 m/s without defoaming
■ w = 0.14-0.15 m/s without defoaming
Xw, %
In Fig.2, a comparative analysis of the foam height of the gas-liquid layer as function of the vapor velocity in the column is made for the model mixture studied with and without defoamer. It is obvious from the figure that
presence of defoamer while, at the same concentrations, foam height varied from 20 to 95 mm. the presence of defoaming agent resulted in decrease of foam height about 2 - 2.5 tims at approximately the same va-
the foam height varied from 17 to 76 mm in por velocity in the column.
A x = 41,6% with defoaming
♦ x = 60,3% with defoaming
■ x = 41,5% without defoaming
• x = 60,3% without defoaming
w, m/s
Fig. 2. Dependence of the height of the gas-liquid layer on the apparent velocity of the vapor in the column (wn)
with and without defoamer
■ w = 0,14-0,15 m/s without defoaming
♦ w = 0,2 m/s without defoaming
X w = 0,17 - 0,18 m/s without defoaming
63 w = 0.14-0.15 m/s with defoaming
;; w = 0.17-0.18 m/s with defoaming
Fig. 3. Dependence of the local efficiency on the composition of the binary mixture Methanol - Water without
defoamer incolumn cube xw
Fig.3 shows the dependence of the local efficiency on the composition of the binary mixture methyl alcohol - water in presence and absence of defoamer at given velocities. As can be seen from the plot, in the range of velocities studied from 0.14 m/s to 0,2 m/s he change of the concentration of the volatile component exerts substantial influence on efficiency of separation in absence of defoamer. In the concentration interval 1,5%, 2,1%, 41,5%, 47,6% and 60,3%, the local efficiency significantly increased with the increase of volatile component content in the initial mixture. For the model mixture studied, the change of the content of methyl alcohol in the initial mixture from 1,5 to 60,3% resulted in change of the local efficiency from 85,61% to 98,89%.
In the same range of velocities 0.14 m/s to 0,2 m/s and concentration interval 1,7%, 2,2%, 41,6%, 47,4% and 60,3% for the mixture methanol - water in presence of defoamer, the change of volatile component concentration in the mixture had negligible effect on the efficiency of separation (the change of the local efficiency was from 81,24% to 86,83%).
Fig.4 shows the experimental data for the influence of vapor velocity (wn) on the local efficiency (
Eqq ) where a comparison is made between model
mixtures methanol - water with and without defoamer.
Fig. 4. Dependence of the local efficiency on the vapor velocity in the column wn and composition of the binary
mixture in the column:
xw =41,6 mol/% h xw =47,4 mol/% in presence of defoamer; xw =41,5 mol/% h xw =47,6 mol/% without defoamer
■ x = 41,6% with defoaming
♦ x = 47,4% with defoaming
▲ x = 41,5% without defoaming
• x = 47,6% without defoaming
100
6 80
o -
60
>
u s ft
► <
Si 15 i> >
11
0,05
0,1
0,15
0,2
0,25
0,3
0,35
wn, m/s
Obviously, at volatile component concentration in the initial mixture 41,6 mol% and 47,4 mol%, the values of the local efficiency in presence of defoamer are by 10% lower. This certainly confirms the fact that the lower foam height in the presence of defoamer, i.e. the smaller interphase area, leads to decrease of the efficiency of the process.
An attempt was made to obtain quantitative estimation of the effect of surface tension on the local efficiency (Eog). The results are presented in Fig. 5 for the mixture methanol - water in presence and absence of defoamer.
■ witout defoaming ♦ with defoaming
M-HHgeKC.10-2
Fig.5. Dependence of local efficiency on the m-index for the mixture methanol - water in presence and absence
of defoamer
The values of the local efficiency for the mixture methanol - water without defoamer increased with the increase of M-index and a linear dependence was observed between the change of the local efficiency and the M-index. In presence of defoamer, however, the increase of the M-index caused decrease of the local efficiency from 87,3% to 84,65%, i.e. it can be assumed that when defoamer is added then the surface tension does not exert significant effect on the degree of separation.
References
1. Foams: Theory, Measurements and Applications, eds. R.K. Prud'homme and S.A. Khan, Surfactant Science Series, Vol. 57, Marcel Dekker, New York, 1996.
2. Defoaming: Theory and Industrial Applications, Vol. 45, ed. P.R. Garrett, Surfactant Science Series, Marcel Dekker, New York, 1993.
3. D.T. Wasan, K. Koczo and A.D. Nikolov, in Foams: Fundamentals and Applications in Petroleum Industry, ed. L.L. Schramm, ACS Symposium Series No. 242, ACS, New York, 1994, Chapter 2.
4. Zuiderweg, F.J., A. Harmens. The influence of surface phenomena on the performance of distillation columns, Chem Eng Sci, 1958, V.9, (2/3), pp.89-103; 1967, V.22, pp.685-692.
5. Ivanov J., J. Stefanov and J. Tasev, Year at the University "Prof. Dr. As. Zlatarov", Burgas, 2006, XXXV, book 1, p. 43 ( Иванов Ж., Ж. Стефанов и Ж. Тасев, Год на У-т "Проф.д-р Ас.Златаров", Бургас, 2006, XXXV, кн. 1, с. 43)
6. N.D. Denkov, K.G. Marinova, Antifoam effects of solid particles, oil drops and oil-solid compounds in aqueous foams. Chapter 10 in the book "Colloidal Particles at Liquid Interfaces" (B.P. Binks & T.S. Horozov, Eds.), Cambridge University Press, Cambridge, UK, 2006; pp. 383-444.
7. Kafarov V.V. Basics of Mass Transfer. Higher school, Moscow, 1972, p. 227. (Кафаров В.В. Основы массопередачи. Высшая школа, Москва, 1972, с. 227.)
8. Zuiderweg F. J., Marangoni effect in distillation of alcohol-water mixtures, Chem. Eng. Res. Des., Vol. 61, 388 (1983).
EXPLORING SOLAR CELLS BY PROGRAMMING LANGUAGES AND SSTANDART PROGRAMS
Khudoynazarov A.
Master student of renewable energy sources Andijan state university
Abstract
In this article provides information about digital modeling programs and programming languages, besides models and programs which are created based on them. Keywords: TCAD, solar cell, model, program
Until the twentieth century, there were two different methods of studying the object in science, theoretical and practical methods. In the middle of the twentieth century, computer technology flourished. This led
to a new approach to science and a new style of research. In the process of complex computing, it is preferable to use computer technology. Because it increases the speed and accuracy of the calculation.
Figure 1. 2D model of a silicon-based solar cell embedded in a nanoparticle generated in Sentaurus TCAD.
