Abstract:
In this study, biodiesel was synthesized using crude palm oil (CPO) with a KOH/CaO
catalyst from blood clam shells that had been calcined at 900 °C for 5 hours. KOH/CaO
catalyst was synthesized using the sol-gel method by adding KOH and ethylene glycol
and it was calcined again at 700 °C for 5 hours. The catalyst analysis used in this study
was XRD to determine the type of minerals contained in the catalyst. Based on the XRD
analysis of the KOH/CaO catalyst, it showed that there were portlandite and calcite peaks
and lime (CaO) peaks were found on the KOH/CaO catalyst of 1 g KOH at 700 °C. The
crystal size of the KOH/CaO catalyst added 0.5 ; 1 and 2 g of KOH were 219.9924,
respectively; 179.9484 and 195.9774 nm. KOH/CaO catalyst was tested in biodiesel
synthesis using various stirring speeds (300, 400, 500, and 600 rpm), at a reaction
temperature of 60°C, a reaction time of 3 hours, a mole ratio of oil: methanol 1:15 and a
catalyst weight of 1%. The most effective catalyst to produce biodiesel was KOH/CaO
1g KOH with a biodiesel yield of 94.91 %. Optimum biodiesel was obtained at KOH/CaO
1g KOH catalyst at 700 °C with a heavy reaction condition of 1 wt% catalyst, the reaction
time of 3 hours, stirring speed of 500 rpm, the temperature of 60 °C and the mole ratio of
oil to methanol 1: 15 resulted in a yield of 94, 91%. Increasing the stirring speed increases
the frequency of collisions with the reactants thereby increasing the yield of biodiesel.
The characteristics of the biodiesel produced are 0.01% water content, specific gravity
880 kg/m3, viscosity 5.38 mm2/s, carbon residue 0.01% by weight, acid number
0.42 mg-KOH/g, saponification number 225.95, the iodine number is 50.44 and the
cetane number is 59.11. In general, the characteristics of biodiesel are following the
requirements of SNI 7182.2015.
