• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2333-2341
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• 2017

Mineral oils are commonly used as transformer insulation oils but these oils are obtained from non-renewable and non-sustainable sources, which is highly undesirable. For this reason, natural ester oils are now being used in replacement of mineral oils because of their good biodegradability, high cooling stability, good oxidation stability and excellent insulation performance. Nanotechnology has gained prominence in both academic and industrial fields over the years and it has been shown in previous studies that nanoscale materials are useful for transformers due to their favourable dielectric properties. The objective of this study is to compare the AC breakdown voltage and viscosity of natural ester oil with three types of nanofluids. The natural ester oil-based nanofluids are prepared by mixing palm fatty acid ester (PFAE) oil with three types of nanoparticles at a concentration of 0.01 g/l: (1) $Fe_3O_4$ conductive nanoparticles, (2) $TiO_2$ semi-conductive nanoparticles and (3) $Al_2O_3$ insulating nanoparticles. The AC breakdown voltage of the oil samples is analysed using Weibull statistical analysis and the results reveal that the PFAE oil-based $Fe_3O_4$ nanofluid gives exceptional dielectric performance compared to other oil samples, whereby the AC breakdown voltage increases by 43%. It can be concluded that the PFAE oil-based $Fe_3O_4$ nanofluid is a promising dielectric liquid to substitute mineral oils.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.3
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• pp.151-156
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• 2009

The purpose of this study is to evaluate the affecting factors on Oil-Mineral Aggregates(OMA) for stranded oil on intertidal flat, because the OMA formation enhances the oil dispersion and biodegradation rates. We choose the affecting factors such as spilled oil concentrations(50, 100, 200, 300, 400, 500 mg/L), mineral concentration(100, 200, 500, 1,000, 2,000, 4,000 mg/L), salinity(10, 20, 30, 40 psu), shaking time(1, 2, 4, 8, 12, 24 hr) and applied dispersant volume(0, 5, 10, 15, 20%). Major conclusions derived from this study are as follows. It was observed that the kaolinite interacts three times strongly with crude oil than quartz. OMA formation was enhanced with increasing of spilled oil concentrations, whereas the increase of salinity rarely affected the OMA formation. The shaking time for OMA formation affected positively with kaolinite, but quartz was irrespective the shaking time. The applied dispersant enhanced the OMA formation by 13% in kaolinite and 56% in quartz experimental condition.

• Journal of Energy Engineering
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• v.25 no.3
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• pp.18-26
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• 2016

Mineral oil is the most widely used for electrical transformer, though some factors should be considered such as their environmentally harmfulness when it spill and low flash point. To cover these disadvantages, vegetable oil has developed because of its high biodegradability and thermal stability. However, it is necessary that many studies should conduct to reveal the detailed impacts of long-term operation as transformer oil. In this paper, we applied the accelerated aging test which simulate the real transformer circumstances using insulation paper, coil, steel at $150^{\circ}C$, which is higher than normal operation, for 2 weeks. To figure out the oxidation characteristics between mineral oil and vegetable oil test major properties and components such as total acid number, dielectric breakdown and dissolved gas components during that period. As a result of these tests, we found that vegetable oil has higher electric insulation ability than mineral oil though poor total acid number by hydrophile property. Vegetable oil also kept its thermal stability under the given circumstances.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.803-812
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• 2023

The subsea separator of an offshore plant for offshore oil and gas development performs the process of separating oil and gas from crude oil produced in the subsea. The oil-gas subsea separator can be divided into a gravity type that separates fluids by gravity and an in-line type that separates fluids using centrifugal force of density. In the case of the deep sea, the development of a small in-line type separator is required due to manufacturing cost and safety problems caused by water pressure. Therefore, in this study, the gas-liquid phase separation efficiency of the subsea separator was identified through the study of the multiphase flow characteristics of the in-line type separator. For the optimal design of the in-line type separator, the shape of the internal swirl element(ISE) was selected first, and the separation efficiency results for each section of the in-line type separator were analyzed. This study was conducted in parallel with experiments and numerical analysis, and it is expected that the reliability and efficiency of the in-line type separator will be improved through the results.

• Geophysics and Geophysical Exploration
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• v.17 no.1
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• pp.34-44
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• 2014

Because offshore plant industry needs to design, deploy and operate much of equipment especially, the latest trend shows the installation of production facilities is augmented in the subsea. The installed facilities are very difficult to be repaired or changed because they are located in the subsea. For solving these problems, both the directly related information of the production like the optimal number, position and depth of wells and the distribution for effective operation and safety of equipment of subsea should be considered at the preliminary stage of FEED (Front End Engineering Design). The marine exploration is introduced in this paper for providing the fundamental technology to answer the questions related to above considering points. First, some kinds of the offshore plant facilities are enumerated and aims of marine exploration for the offshore oil/gas development are summarized. In addition to it, the main roles of marine survey, in the step of designing and installing offshore oil-gas plant, development are briefly listed. And then foreign examples are shown to help the reader's understand. This paper is hoped to be helpful for understanding the marine exploration that can be applied to offshore oil/gas plant and to be contributed to developing the domestic techniques in this field for the future.

• Resources Recycling
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• v.27 no.2
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• pp.55-62
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• 2018

This study aims to investigate the characteristics on bottom ash flotation using vegetable oils as a collector. The experiment of changing the kerosene dosage as a collector for the flotation of coal ashes, the recovery of unburned carbon and unburned carbon content were 80% and 63%, respectively, when the dosage of kerosene was 9 kg/ton. The experiment of using soybean oil as a collector to improve flotation efficiency, the recovery of unburned carbon and unburned carbon content increased to 95% and 68%, respectively, when the dosage of soybean oil was 9 kg/ton. The recovery of unburned carbon and unburned carbon content were 99% and 78%, respectively, when safflower oil containing more poly unsaturated fats with double bonds than soybean oil was 9 kg/ton. The calorific value of the unburned carbon was 5,803 cal/g, confirming that it was possible to be used as a fuel for thermal power plants. Lastly, using vegetable oil as a collector it showed higher recovery of unburned carbon and higher unburned carbon than kerosene, which was mineral oil. Moreover, oil containing a large amount of poly unsaturated fat with two or more double bonds was found to have higher unburned carbon than other vegetable oils; thus showing excellent adsorbability for unburned carbon.

• Journal of the Korean Professional Engineers Association
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• v.18 no.2
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• pp.6-15
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• 1985

A new process disregraded the H$_2$SO$_4$ treatment process heretofore in use, was developed and substituted for mineral base engine used oil of homemade SAE-30 grade H.V.I., which was used covering 4,500km, as samples, and the following results in research, was obtained. (1) A good quality of rerefinded base oil was obtained through roughly a course of developed processes of vacuum distillation process, solvent extraction process, neutralization treatment process and clay treatment process. (2) Through vacuum distillation process, the size of fine grains of insoluble colloid carbon that is, colloid carbon which was produced by burning of internal combustion engine oil and fuel, could be brought up and precipitated (3) The insoluble matters and admixtures could be easily dispersed and dissolved by mixing and extracting solvent disregarded the H$_2$SO$_4$ treatment process heretofore in use (4) waste matter heretofore called acid sludge in consequence of the process, did not appear at all. accordingly, the environmental pollution could be removed. (5) The troubles of corrosion to copper strip which was faults of the usual used oil refined products and peculiar offensive odor of the rerefined oil, could be solved through the neutralization process. (6) The yield of rerefined oil obtained through a course of processes was over 86 percent, and it is of practical use, not to speak of commercial value.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.2
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• pp.119-128
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• 2004

DME(Dimethyl Ether) was directly produced from the synthesis gas using the slurry phase reactor. The catalyst for DME production prepared two types (A type; Cu:Zn:Al=57:33:10, B type; Cu:Zn:Al=40:45:15, molar ratio). It was evaluated for the effect of the reaction medium oil using the small size slurry phase reactor. DME production yield and the methanol selectivity decreased in the order: n-hexadecane oil> mineral oil> therminol oil. The long-term test of DME production was carried out using A and B type catalyst, and n-hexadecane oil and mineral oil, respectively. It was confirmed that the use of A type for the catalyst and n-hexadecane for the reaction medium oil was very useful for the viewpoint of the DME production form the synthesis gas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.605-608
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• 2001

With the intention of investigating the breakdown properties of oil-immersed transformer oils in temperature range of $20\sim100[^{\circ}C]$, we are made researches AC breakdown in the gap of $500\sim2500[{\mu}m]$. The classification for the physical properties of oil for oil-immersed transformer by FTIR and H-NMR experiments was confirmed to type of mineral oils. As the dependance of breakdown properties due to electrode gap length variation, breakdown voltage was found increasing according to the increase of gap, while dielectric strength was decreasing. As a result the characteristics for AC breakdown, It goes to prove that the breakdown voltage was increased to $90[^{\circ}C]$ but decreased over $90[^{\circ}C]$ in the temperature range. Also, breakdown voltage was found increasing in the increase of gap and the rising of temperature according to Weibull distribution.

• Journal of Energy Engineering
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• v.26 no.3
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• pp.131-136
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• 2017

Automobile engine oil is the most important lubricant for operating as the engine is started. Recently, manufacturers of the automotive industry and lubricants are considerably improving the quality of oil with additive to extend change cycle period. Most customers are recommended genuine oil among different types from shop expert. Through this report we suggest another reference point for consumer to pick highly efficient lubricant. This report is investigated oil compounds to compare with 6 different automotive considering actual running condition for 7 months. we conducted experiment from physical and chemical perspectives. In the field, through various experiments oil compounds between mineral oil and synthetic oil are largely distinguished in oxidation, viscosity, fluid and TBN. These are influenced by engine part wear as piston, bearing etc. Comparing various investigation with different oil the performance of synthetic oil is shown better condition in flash point, oxidation stability and also found less in change pollutant iron, Al compounds. Additives of oil show clear difference Ca level in detergent-dispersant both mineral oil and synthetic oil. And Zn in extreme pressure additives and P in Lubricity improver make no difference to both.