Evaluation of in-service oxidative stability and antioxidant additive consumption in corn oil based natural ester insulating fluid

Wilhelm, Helena Maria; Feitosa, Leandro G.; Silva, L. L.; Cabrino, A.; Ramos, Luiz Pereira

doi:10.1109/tdei.2015.7076786

Cited by 15 publications

(5 citation statements)

References 9 publications

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“…It is know that the thermal stress combined with oxygen degrade the triglycerides and produce free fatty acids, which increase the oil acid number [4] [7] [28] [32].…”

Section: Accelerated Agingmentioning

confidence: 99%

“…In the last half of the last century, synthetic hydrocarbon fluids, silicone, and ester fluids were introduced, but, at that time, their use was limited [5]. Furthermore, mineral oils are non-biodegradable, high flammable (due its low flash point) and dangerous for the environment, since spills from leaks and equipment failure can contaminate the water and the soil [4] [6] [7].…”

Section: Introductionmentioning

confidence: 99%

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Development of a New Bio-Based Insulating Fluid from <i>Jatropha curcas</i> Oil for Power Transformers

Evangelista¹,

Coelho²,

Carvalho³

et al. 2017

ACES

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The present work aims to develop a new vegetable insulating fluid for power transformers based on Jatropha curcas oil. Besides its technical benefits, Jatropha curcas oil has a socioeconomic role by promoting income to rural families, contributing to the countryside development and avoiding rural exodus. Thus, the entire transformer oil production (extraction, processing, characterization and accelerated aging) was covered and a new process was developed. For oil extraction, the most suitable process was the solvent extraction (5 mL of hexane per gram of crushed non-peeled seeds during 30 minutes) with an oil yield of 32%. In raw oil processing stage, the degumming, with 0.4 g of phosphoric acid per 100 g of oil, at 70˚C, was used to remove phosphatides. Then, free fatty acids were 96% neutralized with a sodium hydroxide solution (0.5% w/w) at room temperature. For the oil clarification, the combination of 5% w/w oil of activated carbon and 1% w/w oil of MgO resulted in a bright, odorless and clear oil with an acid number of 0.04 mg KOH •g −1 . The oil drying in a vacuum rotary evaporator, at 70˚C, for 2 hours reduced the water content to 177 ppm. The processed oil was characterized following ASTM D6871 methods. This oil presented higher dielectric breakdown voltage (55 kV) than commercial transformer fluids (BIOTEMP®, EnvirotempFR3®, and Bivolt®), which increases transformer safety, capacity and lifetime. In addition, the processed oil has a lower viscosity than BIOTEMP® fluid, which can enhance the heat dissipation efficiency in the transformer. Moreover, the processed oil flash and fire points of 310˚C and >340˚C, respectively, confirm the great security of vegetable insulating fluids. The analyzed properties of the processed oil fulfill all the ASTM D6871, ABNT NBR 15422 and IEC 62770 specifications. Therefore, Jatropha curcas oil is a potential substitute formineral insulating fluids.How to cite this paper: Evangelista Jr.,

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“…It is know that the thermal stress combined with oxygen degrade the triglycerides and produce free fatty acids, which increase the oil acid number [4] [7] [28] [32].…”

Section: Accelerated Agingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development of a New Bio-Based Insulating Fluid from <i>Jatropha curcas</i> Oil for Power Transformers

Evangelista¹,

Coelho²,

Carvalho³

et al. 2017

ACES

View full text Add to dashboard Cite

show abstract

“…The shell was then crushed, grinded and then sieved (38-75 µm). It was then heat treated in a furnace [19]. After which it was calcined at 1000 ºC for 4 h at heating rate of 10 ºC /min in air atmosphere.…”

Section: Preparation and Characterization Of Catalystmentioning

confidence: 99%

Development of Eco-Friendly Transformer Oil from Neem Seed Oil using Periwinkle Waste Shell as Catalyst

Oyelaran

Borisade

Abioye

et al. 2022

Environmental and Climate Technologies

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The urge for a sustainable and non-polluting industry has raised the need for a search for an alternative insulating fluid that could be used in transformers, because of the negative environmental effect of mineral-based insulating fluids. Natural esters from non-edible oil seeds showed to be feasible alternative, unfortunately they possess poor thermooxidative properties. Neem trees grow nearly on all types of soils and can be as old as 45 years before they start to produce less fruits. Neem tree can produce up to 50 kg of its fruits yearly from the tenth year and the seed oil content is 45 % making it a sustainable tree. The neem seed transformer oil (NSTO) was produced via catalysed transesterification process using neem seed oil and methanol with periwinkle shell as catalyst. Prior to the transesterification reaction the seed oil was degummed. The produced ester also underwent water treatment process. The produced NSTO density, water content, acidity flash point, pour point, viscosity, breakdown voltage, dielectric, relative dielectric constant, dissipation factor and resistivity properties were tested, presented and discussed. Results show that NSTO meet most of the standard requirements of new natural ester fluids as insulating oil. The dielectric breakdown voltage of the oil is 32 kV, which is more than the required for new natural ester fluids. The dissipation factor limit value for new natural ester of 0.20 % at 25 °C limit value was met by NSTO from 100 Hz to 400 Hz, and the relative dielectric constants of NSTO are 3.01 k, which value also meets the specification of between 2.9 k and 3.2 k. The pre-treatment of degumming of the seed oil prior to transesterification and water treatment of the produced ester appears to be a promising route for the production of electrical insulating oil for transformer.

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“…The oxidation stability of NEs can be improved by adding an oxidizing inhibitor (antioxidants) such as Butylated hydroxytoluene (BHT) or the tertiary butyl hydroxylquinone (TBHQ) [18 -26]. However, the amount (doping concentration) of antioxidants to be added must be optimal so as not to affect the dielectric properties of the liquid [18][19][20][21][22][23][24][25][26][27][28][29][30]; the recommended limit value is of 0.3 wt%. Otherwise, the electrical conductivity and dielectric loss of the oil will dramatically increase.…”

Section: Introductionmentioning

confidence: 99%

A Review on Electrical Breakdown of Natural Ester-Based Nanofluids Under Different Voltage Waveforms

Beroual,

Alkuhayli,

Mahmoud

et al. 2024

IEEE Access

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Environmental, safety, and availability constraints of mineral oils have led transformer manufacturers and researchers to turn to alternative liquid dielectrics to mineral oils. Thus, many works have focused on esters and more particularly on natural esters (NEs); commonly called vegetable oils; in recent decades. Besides their advantages (biodegradability, non-toxicity, recyclability, thermal stability, and safety) compared to mineral oils, natural esters have certain disadvantages including their high viscosity and their oxidation instability. Both of these properties can be improved by adding specific additives and nanoparticles. This paper is mainly focused on review of the breakdown voltage of natural ester-based nanofluids, one of the most significant parameters when selecting insulating fluids for high voltage devices and in particular for power transformers. Firstly, we take stock of the history of the introduction of fluids/oils in the field of electrical insulation and the return of vegetable oils in the transformer industry. Then, we present the main characteristics of vegetable oils and the different products based on vegetable oils currently on the market as well as those that are currently the subject of research and plants from which they come. The methods and techniques for the preparation/elaboration of these nanofluids and their stability are then exposed. Finally, we present the different results reported in the literature on the electrical breakdown of various types of natural esters when adding nanoparticles (NPs) issued from different materials (conducting, semiconducting, and insulating), under AC, DC and lightning impulse voltages, and discuss the involved mechanisms in the breakdown of nanofluids.

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Evaluation of in-service oxidative stability and antioxidant additive consumption in corn oil based natural ester insulating fluid

Cited by 15 publications

References 9 publications

Development of a New Bio-Based Insulating Fluid from <i>Jatropha curcas</i> Oil for Power Transformers

Development of a New Bio-Based Insulating Fluid from <i>Jatropha curcas</i> Oil for Power Transformers

Development of Eco-Friendly Transformer Oil from Neem Seed Oil using Periwinkle Waste Shell as Catalyst

A Review on Electrical Breakdown of Natural Ester-Based Nanofluids Under Different Voltage Waveforms

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Evaluation of in-service oxidative stability and antioxidant additive consumption in corn oil based natural ester insulating fluid

Cited by 15 publications

References 9 publications

Development of a New Bio-Based Insulating Fluid from &lt;i&gt;Jatropha curcas&lt;/i&gt; Oil for Power Transformers

Development of a New Bio-Based Insulating Fluid from &lt;i&gt;Jatropha curcas&lt;/i&gt; Oil for Power Transformers

Development of Eco-Friendly Transformer Oil from Neem Seed Oil using Periwinkle Waste Shell as Catalyst

A Review on Electrical Breakdown of Natural Ester-Based Nanofluids Under Different Voltage Waveforms

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Development of a New Bio-Based Insulating Fluid from <i>Jatropha curcas</i> Oil for Power Transformers

Development of a New Bio-Based Insulating Fluid from <i>Jatropha curcas</i> Oil for Power Transformers