Experimental investigation of the production of biolubricant from waste frying oil

In this study, waste sunflower frying oil used in fish frying was used for the synthesis of biodiesel and biolubricant through a transesterification reaction. It has been seen that single catalyst trials have been done in the literature. In this study, experiments were carried out using both a single catalyst and a triple catalyst mixture. The catalysts used in the study can be said as potassium hydroxide, magnesium hydroxide, calcium carbonate, dopamine, and bentonite-chitosan-KOH, respectively. In the experiments using pure potassium hydroxide, one of the selected catalysts, better results were obtained compared to the others. In the study performed with pure potassium hydroxide, the highest yield value was found with 88.4% fatty acid methyl esters (FAME). Yield values were low in the experiments using ethyl alcohol. The reason for this is known from the literature that the use of ethyl alcohol as a solvent for the catalyst negatively affects the ambient reaction. In addition, as it is known from the literature, the use of methyl alcohol affects the reaction positively. In the preliminary experiments, it was seen that the parameters affecting the reaction were temperature, time, amount of catalyst, and methanol/oil ratio. The stirring speed was a constant value of 600 rpm. The best conditions for getting the highest conversion rate were studied with KOH catalysts at 65 degrees C for 120 min, 5/1 methanol oil ratio, and a 1% catalyst amount. The biodiesel yield was low in the experiments with the other catalysts. Besides, biodiesel was analyzed for its heating value, density at 15 degrees C, viscosity at 40 degrees C, flash point, water, and cloud point. The structure of the produced biolubricant was tested using Fourier transform infrared (FTIR), and its thermal stability was investigated using thermogravimetric analysis (TGA) technique. The pour point, flash point, viscosity index, and viscosities of the biolubricant at 40 degrees C and 100 degrees C were determined.

Automated summary

This study utilized waste sunflower frying oil to synthesize biodiesel and biolubricant via a transesterification reaction. Experiments were carried out using both single catalysts and a mixture of three catalysts, with pure potassium hydroxide yielding the best results. The optimum conditions for the highest conversion rate were determined to be using potassium hydroxide as the catalyst at 65°C for 120 minutes, with a methanol/oil ratio of 5/1 and a catalyst amount of 1%. Various properties of the biodiesel were analyzed, and the structure and thermal stability of the biolubricant were examined.