The Experimental Study On The Potential Of Waste Cooking Oil As A New Transformer Insulating Oil

Power transformers use mineral oil as an insulating liquid due to its outstanding dielectric properties. The poor biodegradability and toxicity of mineral oil have increased the interest in the use of a more environmentally friendly product such as ester-based oil. Generally, natural ester insulating oils (NEI) have a higher flash point and breakdown voltage compared to existing mineral oils. However, the higher price of NEI is the main obstacle to widely applied in power transformers. Therefore, alternative cheaper feedstock processing is required. This paper proposed waste cooking oil (WCO) as a potential alternative to the existing transformer insulating oil. The used of WCO promotes the optimal consumption of plant-based resources and more efficient waste management. Transesterification method is performed to remove the free fatty acids in the WCO and reduce the viscosity. The transesterification process is based on the chemical modification reaction between WCO, methyl alcohol (methanol) and sodium hydroxide (NaOH) catalyst lye that produces waste cooking oil methyl ester (WCOME). Chemical and electrical properties i.e. water content, acidity and breakdown voltage of the developed WCOME are compared with the existing WCO according to IEEE Guide for Acceptance and Maintenance of Natural Ester Fluids in Transformers (IEEE C57.147

Non-noble supported catalyst for oxidation of glucose under mild reaction conditions

Catalytic oxidation of D-glucose to D-gluconic acid derivative with H2O2 has been studied using non-noble Cobalt supported catalyst. The catalysts were synthesized using the scalable incipient wetness impregnation method of Co/Al2O3 and Co/TS1. The catalysts have been characterized by TGA, XRD, FESEM-EDX, BET, FTIR, and Hammett test. The oxidation of the D-glucose into D-gluconic acid with yield of 82% (as sodium gluconate) and selectivity is about 100 % have been achieved in the presence of 5 wt.% Co/Al2O3 as a catalyst under mild reaction conditions (60 oC, pH 9, 1atm, 3h). Reusability study of Co/Al2O3 was proven to be stable for subsequent cycles of reaction with no notable changes in selectivity. Besides, the physic-chemical properties of spent catalyst were similarly characterized through FTIR and Hammett test analysis. The presence of gluconic acid was confirmed by HPLC. The apparent activation energy of reaction is 15 kJ mol-1 which is lower than the value reported by prior-art using gold catalysts suggesting different mechanism with dissimilar rate-determining step. The activation of H2O2 is mediated by Co crystallites on the catalyst surfaces, forming active oxygen species via hydroxyl and peroxyl radical intermediates and/or oxometal species. The basic sites on catalyst facilitate the activation of glucose. The findings could help to make a cost-effective catalyst for D-glucose conversion into valuable organic acid chemical

Effect of electrolyte thickness manipulation on enhancing carbon deposition resistance of methane-fueled solid oxide fuel cell

Dual-layer hollow fiber (DLHF) micro-tubular solid oxide fuel cell (MT-SOFC) consisting of nickel oxide-yttria-stabilized zirconia (NiO-YSZ) anode/YSZ elec�trolyte was fabricated via a single-step phase inversion-based co-extrusion/co�sintering technique in order to investigate the effect of different electrolyte extrusion rates (1-5 mL min−1 ) at different sintering temperature (1350�C, 1400�C, and 1450�C) under methane (CH4) condition. The DLHF co-sintered at 1450�C was chosen as optimum temperature due to the good mechanical strength and gas-tight property. Meanwhile, 18 to 34 μm of electrolyte thick�ness was achieved when electrolyte extrusion rate increase from 1 to 5 mL min−1 . Power density as high as 0.32 W cm−2 was obtained on the cell with the electrolyte layer of 18 μm in thickness (DLHF1) which is 20% higher than the cell with an electrolyte layer of 34 μm (DLHF5) which was only 0.12 W cm−2 when operated at 850�C. However, DLHF1 had suffered cracking formation that originated from anode site which shortened the stability test duration to only 8 hours of survival under 750�C. While DLHF5 can operate up to 15 hours but an increase in electrolyte thickness had resulted in higher ohmic area-specific resistance that lowering the power density. Fifty-seven per�cent reduction in cell performance was observed under methane condition when compared to the cell that performs using hydrogen gas due to the carbon deposition as proven by Raman spectroscopy and carbon, hydrogen, nitrogen, and sulfur analyzer

Cobalt supported alumina catalyst for oxidation of glucose to gluconic acid under mild reaction conditions

Glucose is one of the most essential carbohydrate feedstock for the production of industrial chemicals [1]. One of the important and valuable chemical as a starting feedstock to produce gluconic acid [2, 3]. On the rise of industries and new applications of gluconic acid, further increase in demand is expected to continue rising in future [4]. As the commercialize biochemical route is not recyclable, possesses negative impacts to environment and other drawbacks, many researchers have put much attention towards catalytic oxidation of glucose to gluconic acid with the use of selective heterogeneous catalyst. However, the selective oxidation of glucose is quite challenging as to the activity of catalyst and low conversion. These pose difficulties in designing process, operation and production at industrial scale [5]