Impact of adding activated bentonite to thermally aged ester‐based TiO₂nanofluids on insulation performance

Abstract

The authors report the key findings from an experimental study that explored the use of activated bentonite for the reclamation of thermally aged ester‐based transformer nanofluids to improve their insulation performance. Bentonite activated with acid treatment caused an increase in the specific surface area and pore volume of bentonite compared to the bentonite sample before treatment, thus imparting an improved adsorption capability. Physico‐chemical diagnostic studies were carried out to characterise the activated bentonite. The insulation performance of the reclaimed natural ester and nano‐filled ester fluid samples was assessed by measuring the corona inception voltage and breakdown voltage of each fluid sample, apart form measuring the flow electrification current using the spinning disk method. The results revealed that the reclamation process improved the corona inception voltage, dissipation factor and the breakdown voltage of the base ester fluid sample due to attraction of carbon particles to activated bentonite, but no significant variation was observed with nanofluids due to the depletion of the electrical double layer. The flow electrification current of ester and ester nanofluids reduced after treatment with activated bentonite, may be attributed to the interaction between copper and bentonite that alters the double layer formation responsible for the separation of charges.

Bleaching of crude marula oil using activated bentonite and activated marula shells: A comparative analysis

“…Weight loss also appeared at second degradation with mass losses of 5% and 2% for FB and AB, respectively and this was attributed by hydroxylation which is desorption of -OH groups from the surface of bentonite material in water form Martín et al (2021). The second decomposition occurred at 597℃ for both FB and AB and from the graphs after decomposition, fresh bentonite sample remains with a higher residue compared to acid activated bentonite Amalanathan et al (2021). This is because hydroxyl groups and interlayer water become less due to activation process thereby easy decomposition of AB Mao et al (2020) resulting in less residue.…”

Adoption of response surface methodology for optimization of benzotriazole additive in ester fluids as transformer insulant

“…The dissipation factor of ester fluids was measured at different temperatures as per IEC 60247 standard [29]. Table 1 shows the properties of ester fluids used in the present research work.…”