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ТЕХНИЧЕСКИЕ НАУКИ
Yusupov Dilmurod Turdaliyevich,
LLC «Scientific and technological center» of JSC «Uzbekenergo»,
junior researcher Tashkent, Uzbekistan Umirova Nilufar Ravilevna,
Tashkent state technical university, assistant Tashkent, Uzbekistan Pulatova Dilnoza Mannanovna, Tashkent state technical university, assistant Tashkent, Uzbekistan
PURIFICATION OF TRANSFORMER OIL FROM WATER
Analysis of influence of water on operational properties of oil in the course of long operation of the power transformer is carried out in the article. The carried out analysis showed that the emulsified water is the most dangerous to lifecycle of the power transformer as reduces the puncture voltage of transformer oil. With respect there to, purification of the wasted transformer oil with silica gel and zeolite in a combination of ceramic membranes is carried out. Application of the adsorptive method with a combination of ceramic membranes allowed carrying out effectively purification of transformer oil from emulsified water.
Key words: power transformer, transformer oil, water, ceramic membrane, silica gel, zeolite, mobile installation.
Transformer oil, being used for isolation and cooling, also defines quality of working of oil transformers. As, 85% of breakages of oil transformers happen because of damage of isolation [1]. In this regard more actual task is timely purification and regeneration of oil of power transformers with their long exploitations.
In exploitation transformer oil contains the water which is contented in the process of aging of oil and cellulose isolation and also the water getting to oil from environment. The insignificant amount of water can have considerable influence to features of exploitation of the transformer. For example, if contents of water in transformer oil are exceeded by 50 ppm, then there can be a breakdown that leads to a transformer exit out of operation [2]. The carried-out analysis [3] shows that the content of water in transformer oil is the main reason for various type of damage of power transformers.
Depending on content of moisture in transformer oil water can be in three states: free, emulsified and connected.
Free water has the large form, doesn't mix up with transformer oil and easily separates from his structure.
The emulsified water consists of small drops of liquid. Droplets of this water can be besieged or under
the influence of electric field to be built in chains and to form the carrying-out bridges [4] and as a result of, this type of water, can influence to the puncture voltage of transformer oil. The puncture voltage of oil is the indicator characterizing ability of liquid dielectric to maintain the impressed voltage without breakdown. The carried-out researches [5] claim that increase the emulsified water in content of transformer oil suddenly goes down of puncture voltage as it is given in figure 1. Under the influence of electric field of a drop of the emulsified water in oil are involved to places where voltage of electric field is higher and where begins emergence of breakdown [6].
The connected water has very small form, the chemical composition of this water is strong connected with a chemical composition of transformer oil and, it is almost impossible to be exempted from her. She also contains in fresh oil. On the other side, the connected water doesn't render an essential harmful influence on electro physical indicators of transformer oil [7].
In this regard, the purpose of this work is purification of transformer oil from the emulsified water for increase its puncture voltage.
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SO 100 120
Concentration of water with oil, ppm
Figure 1. Influence of water to the puncture voltage of transformer oil
The sample of waste transformer oil with long exploitation is received by authors from the specialized repair enterprise JSC "Energotamir" to carrying out of research works. This received transformer oil has been taken from the power transformer, which is working since 1976 year.
Various methods are applied to carrying out regeneration of the waste transformer oil from water. On the basis of the carried-out analysis [8-10] authors offer table 1, where are given efficiency of the existing methods of regeneration of the waste oil from water.
Table 1.
Efficiency of the existing methods of regeneration of the waste oil from water
Name of technology of regeneration Principle of operation Efficiency of purification
from free water from the emulsified water from connected water
Upholding Is based on natural sedimentation of water, being in a suspension, at quiet standing of oil. Delete Dont delete Dont delete
Centrifugal separation One of methods of removal of water of oil is carried out by means of centrifuges. The method is based on division of various fractions of non-uniform mixes under the influence of centrifugal force. Delete Delete Dont delete
Adsorption purification It is based on water absorption by various adsorbents on an external surface of granules and on an internal surface of the capillaries penetrating granules. Delete Delete Delete
The adsorptive way is applied for purification of transformer oil from the emulsified water. As adsorbents silica gel and zeolite are used.
For deleting of mechanical impurity from transformer oil by authors have developed ceramic membranes with an average size of with porosity 1-3 microns.
Regeneration of transformer oil was carried out according to the closed scheme [11]. The waste transformer oil heated to 70°C moves to the box with adsorbents (silica gel) in which oil is exposed to percolare (course of liquid through porous material) influence and comes to the block of a ceramic membrane. If necessary oil is outgases by pumping out and goes to the second cycle of cleaning - to the box with adsorbents.
Repeated circulation of oil allows to achieving the necessary level of cleaning.
Optimum results have been received when total time of contact of adsorbents with oil made not less than 4 hours. The purified sample oils at a temperature 50-70 °C have been passed through porosity silica gel for deleting of products of aging of transformer oil. Then oil is cleaned by ceramic membranes.
The analysis of the regenerated transformer oil has shown its high dielectric properties, however availability of residual water hasn't allowed to reach the required level of electric durability of sample oil - 51 kV (norm - 60 kV). Availability of residual water found as a result of researches on the laser analyzer (firm "Malvern Ltd.") distributions of particles by the sizes.
For the purpose of the residual, that is emulsified water and increase the puncture voltage of transformer oil has been subjected to regeneration by zeolite in combination with silica gel and ceramic membranes.
The analysis of the regenerated oil has also shown high dielectric properties (tg8=0,20 at 90°C, at norm -1,7%), the electric durability of a sample - 60 kV (at norm of 60 kV), the content of organic acids - 0,018
Electro physical properties of oil
milligram hydroxide potassium/gram in oil (at norm -0,02 milligram hydroxide potassium/gram).
The analysis of samples of transformer oil purified through silica gel, ceramic membrane and zeolite, on the laser diffraction analyzer of particles has shown that there is no emulsified water in submicron area.
Electro physical parameters of transformer oil before and after purification are shown in table 2.
Table 2.
N Electro physical properties of oil Before purification After purification (silica gel + ceramic membrane) After purification (silica gel + ceramic membrane + zeolite)
1. Electric durability 22,8 kV 51 kV 60 kV
(puncture voltage) (Norm 60 kV) (Norm 60 kV)
2. Water content Be present Be present Be absent
3. Mechanical impurity Be present Be absent Be absent
4. Content of the weighed coal Be present Be absent Be absent
5. Colour Brown Yellov Yellow
6. the content of organic acids (mil- 0,030 0,019 0,018
ligram hydroxide potassium in 1 gram oil) (Norm 0,020) (Norm 0,020) (Norm 0,020)
7. Outbreak temperature 147°C (Norm 135°C) 151° C (Norm 135°C) 151° C (Norm 135°C)
8. Dielectric losses 2,05% 0,05% 0,05%
Tangent of angle 5 at 200C
Tangent of angle 5 at 700C 6,86% 0,14% 0,14%
Tangent of angle 5 at 900C 13,0% (Norm 1,7%) 0,30% (Norm 1,7%) 0,20% (Norm 1,7%)
Laboratory researches on the adsorptive purification of oil with use ceramic membranes have shown high dielectric properties of the purified oil. Apparently from the table 2, oil is quite conformed to requirements of normative documents [12-13].
In figure 2 it is given spectral dependences of coefficients of a transmission of transformer oil before and after purification [14]. It is visible from graphics that regeneration has led to essential clarification of transformer oil.
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O
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1,0
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0,0
Cleaned oil (silica gel, ceramic membrane, zeolite)
Waste oil
350
400 450 500 550 600 650 700 750 Wavelength, X
Figure 2. Spectral coefficients of transmission transformer oil before and after purification in comparison.
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Working capacity of the adsorptive method allows offering mobile installation for cleaning of the power transformer. In this case the tank of the power transformer joins in the technological scheme and there is a purification of oil in the mode of circulating pumping. This mode allows using the adsorptive method for washing the isolation and tank. It can be carried out by mobile installation.
The schematic diagram of mobile installation is given in figure 3 [15]. The waste transformer oil is pumped over by a circulating oil pump (2) from the
power transformer (1) and transferred into the electric heater (3) where heats up until temperature of 70°C. Heated oil moves to the box with adsorbent (silica gel) (4) and it cleans from various chemicals. Then oil is passes in to adsorbent (zeolite) (5) and it cleans from emulsified water. Further oil arrives in the ceramic filter (6) for cleaning from mechanical impurity. Then the purified oil moves in a broad tank (7) of the power transformer. Repeated circulations of oil allow achieving the necessary level of purification.
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14
MxH
12
MXH
13
o~u o
2
Figure 3. Schematic diagram of mobile installation: 1 - power transformer; 2 - circulating oil pump; 3 - oil electric heater; 4 - adsorbent (silica gel); 5 - adsorbent (zeolite); 6 - ceramic filter; 7 -; 8 - connecting pipeline; 9, 10, 11, 12, 13, 14 - locking valves;
Using of the adsorptive method with a combination of ceramic membranes for purification of the waste transformer oil from the emulsified water is the most effective, from the economic point of view.
Carrying out timely regeneration of the waste transformer oil will allow increasing energy efficiency and reliability of working of the power oil transformer with long exploitation.
References
1. Bogachkov I.M., Savinih YU.A. Regeneratsiya transformatornogo masla vrashayushimmsya magnit-nim polem. Nauchno-tehnicheskiy jurnal "Geologiya, geografiya i globalnaya energiya", 2010 g., №3 (38), str. 79-80.
2. M.A. Suslin, V.A. Tetushin, V.N. CHernihsev, D.A. Dmitriev // Mikrovolnovoy termovlagometrich-eskiy metod kontrolya organicheskih soedineniy, Vest-nik TGTU, 2004 g., Tom 10, №2. http://cyberleninka.ru/article/n/mikrovolnovoy-termovlagometricheskiy-metod-kontrolya-organicheskih-soedineniy
3. Pankaj Shukla, Y.R. Sood, R.K. Jarial. Experimental Evaluation of Water Content In Transformer Oil
// International Journal of Innovative Research in Science, Engineering and Technology, Vol. 2, Issue 1, January 2013. Pages 284-291.
4. G.V. Popov. Voprosi diagnostiki silovih trans-formatorov //FGBOUVPO "Ivanovskiy gosudarstven-niy energeticheskiy universitet". - Ivanovo, 2012 g., -176 str.
5. T. Toudja, A. Nacer, H. Moulai, I. Khelfane, A. Debche. Physico-chemical properties of transformer mineral oils submitted to moisture and electrical dis-charges// International Conference on Renewable Energies and Power Quality. Santiago de Compostela (Spain), 28 th to 30 th March, 2012. http ://www. icrepq. com/icrepq'12/538-toudj a.pdf
6. B.I. Nevzlin i drugiye. Sposob podderjaniya vi-sokogo urovnya electricheskoy prochnosti transforma-tornogo masla // ISSN 1993-9981 Metodi ta priladi kontrolya yakosti, №26, 2011 g., str. 49-50.
7. A.V. Koval i drugiye. Vliyanie nekotorih faktorov na ekspluatatsionnniye svoystva transforma-tornogo masla // Problemi energetiki, №1-2, 2005 g., str.100-104.
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8. Shuvarin D.V. Noviye tehnologii ochistke i re-generatsii energeticheskih masel. http://www.sib-diag. ru/2015/presentation/2 11 .pdf
9. Bogachkov I.M., Savinih YU.A. Sposob ochistki transformatornogo masla // Jurnal «Neft I gaz », №1, 2011 g, - str. 87-91.
10. Gorbunov N.I. i drugiye. Povisheniye effek-tivnosti regeneratsii otrabotannogo masla //Visnik SevNTU: zb, nauk. pr. Vip. 122/2011. -str.159-162.
11. Salikhov T.P., Kan V.V., Askarov SH.SH., Yusupov D.T. Economic aspects of transformer oil regeneration // Uzbek journal of the Problems of informatics and energetics. #3-4, 2014, pages 85-89.
УДК 536.24:533.6.011
12. GOST 6370-83. Neft, nefteprodukti i prisadki. Metod opredeleniya mehanicheskih primesey. - Moskva: Izdatelstva standartov. 1983, 7 str.
13. Instruction. Exploitation of transformer oil. Normative document RH 34-301-633:2011.
14. Kan V.V., Yusupov D.T. Cleaning of oil transformers with use mobile equipments on the basis of ceramic membranes // Uzbek journal of the Problems of informatics and energetics. #6, 2014 pages 85-89.
15. Yusupov D.T. Circulating way of cleaning of cellulose isolation of power oil transformers// European Applied Science, #12, 2015, pages 53-56.
C.I. Трубачев, О.В. Баранюк, В. С. Мельник СТРУКТУРА ПОТОКУ ПРИ TE4IÏ В СЕРЕДЕН1 ГВИНТОПОДIБНОÏ ТРУБИ
С.И. Трубачев, А.В. Баранюк, В. С. Мельник СТРУКТУРА ПОТОКА ПРИ ТЕЧЕНИЯ В СЕРЕДИНЕ ВИНТООБРАЗНОЙ ТРУБЫ
S. Trubachev, A. Baranyuk, V. Melnik STRUCTURE OF FLOW FLOW IN
Проведено дослщження структури течи та полiв осередненно! швидкосп при течи повпряного потоку в середиш латунно! гвинтоподiбноi труби з рiвнорозвиненою поверхнею засобами СРБ-моделювання. Метою роботи е визначення оптимальних геометричних характеристик гвинтоподiбних труб, яш плануеться використати для створення теплообмшного апарату. Верифжаци даних СРБ-моделювання здшснювалась за допомогою ствставлення з тестовою задачею вщомою з лггератури.
Ключовi слова: теплообмiн, гвинтоподiбна труба, рiвнорозвинена поверхня, вимушена конвекцiя.
Проведено исследование структуры течения и полей осреднения скорости при течении воздушного потока внутри латунной винтообразной трубы с равноразвитой поверхностью средствами CFD-моделирования. Целью работы является определение оптимальных геометрических характеристик винтовых труб, которые планируется использовать для создания теплообменного аппарата. Верификации данных CFD-моделирования осуществлялась с помощью сопоставления с тестовой задачей известной из литературы.
Ключевые слова: теплообмен, винтообразная труба, равноразвитая поверхность, вынужденная конвекция.
1. Вступ
На сьогодшшнш день юнуе необхвдшсть по-лшшення роботи газотранспортно! системи Укра-!ни за допомогою застосування повiтронагрiвачiв (регенераторiв) для утилiзацii теплоти ввдпрацьова-них в турбiнi газiв. В той же час регенератори при сьогодшшньому рiвнi !х використання е громiзд-кими i металоемними, часто мають низьку експлуа-тацшну надiйнiсть. Тому створення нових ГТУ з високими технiко-економiчними показниками i мо-дернiзацiя iснуючих неможливо без використання в !х конструкцiях надшних i ефективних поверхонь теплообмiну. Таким вимогам ввдповвдають розроб-ленi новi поверхнi - гвинтоподiбнi труби з рiвно-розвиненою поверхнею.
Гвинтоподiбнi теплообмiннi труби з рiвнороз-виненою поверхнею, що пропонуються, не мають аналогiв у свiтi, всебiчно дослiджувались авторами [1-3]. 1хня конструкщя дозволяе одночасно суттево збiльшити як зовшшню, так i внутрiшню поверхню теплообмiну (в 1,15-1,4 рази). Завдяки гвинтоподь
бним виступам-впадинам, якi послвдовно чергу-ються з заданою висотою-глибиною та кроком, вони спричиняють додаткову турбулiзацiю приме-жового шару [3]. За рахунок закрутки внутршнього та зовшшнього потокiв i рiзкоi' змiни швидкосл потоку при омиваннi поверхш вiдбуваеться одночасне збiльшення iнтенсивностi внутршнього i зовшш-нього теплообмiну в залежносп вiд геометричних характеристик труб та крошв мiж ними у 1,5-2,5 та 1,1-1,3 рази ввдповщно. За рахунок цього коефщь ент теплопередавання збiльшуеться на 25-70% в по-рiвняннi з трубами круглого перерiзу.
Технологiю отримання гвинтоподiбних профь лiв на трубках, що базуеться на використанш трьох роликово! обкатно! головки сумiсно з одно ролико-вою обкатною головкою розроблено в ММ1 КП1 iм. 1горя Окорського [4].
Дослiдженi авторами [1-3] гвинтоподiбнi труби мали зовнiшнiй дiаметр 36 мм i невеликi кроки мiж впадинами та виступами (8-12 мм) при висотах впадин чи вистутв (4-5 мм). Вказаний дiа-пазон досить вузький, тому з метою створення умов
