Optimization of used cooking oil for biodiesel using CaO-derived of bovine bone catalyst

Abstract

Utilization of low-grade Used Cooking Oil (UCO) for biodiesel is addressed to participate in three key issues health, environment, and renewable energy. This work optimized UCO and natural CaO catalyst made of bovine bone for biodiesel conversion. UCO quality was analyzed and treated to reduce FFA. A natural base catalyst was prepared by soaking bovine bone in acetone and calcinated at 800°C for 3 h. Afterward, UCO conversion was estimated with saponification method by setting NaOH solution and mixing period. Finally, UCO to biodiesel was converted using the natural CaO catalyst and ethanol. UCO conversion optimization was conducted by setting experimental design with parameters ratio of catalyst: UCO starting at 5, 7.5, 10, 12.5, and 15 % and temperature 66, 72, and 78°C. The results showed that the natural CaO characterization was a strong base catalyst with a basicity of 0.5599 mmol-CO2 g−1 with 57.3 % CaO that distributed well on the surface of the catalyst. UCO conversion was successfully saponified by mixing UCO in 0.4 M NaOH for 3 h. The model of response surface showed that research design was significantly influenced by temperature and catalyst amount. Moreover, catalyst regeneration could be done by soaking in acetone and heating up at 800°C for 3 h. UCO conversion was converted up to 73.53% using 300 % excess ethanol with 15 % catalyst at 78°C. Selectivity of the natural catalyst reached 39.05 % with other dominant byproducts consisting of alcohol including glycerol and aldehyde. Biodiesel was examined its 8 properties: density, kinematic viscosity, free glycerine, total sulphur, copper blade corrosion, carbon residue and cetane number, fulfilled the requirement for biodiesel blending 30 % (B30).

Keywords

• UCO-biodiesel conversion with saponification
• Low grade UCO for biodiesel
• FFA reduction
• Cow bone base catalyst
• Catalyst characterization