Abstract:
Fossil fuels that are not environmentally friendly and their presence is decreasing due to
their increasing use has spurred researchers to produce alternative fuels from renewable and
environmentally friendly sources, one of which is biodiesel. In this study, biodiesel was
synthesized from crude palm oil (CPO) using a KOH/CaO catalyst from blood clam shells
calcined at 900 °C for 5 hours. KOH/CaO catalyst was synthesized using the sol-gel
method and then calcined at 700 °C for 5 hours. The catalyst was characterized by SEM to
determine the morphology. The morphology of the catalyst is 0.5 g KOH/CaO the pores are
still visible and the surface of the catalyst is slightly rough, catalyst 1 g KOH/CaO the pores
are not visible so that the surface of the catalyst looks smooth and catalyst 2 g KOH/CaO
the pores are not visible but the surface of the catalyst is rough. The activity of the catalyst
was tested in biodiesel synthesis with variations in reaction time (1, 2, 3 and 4 hours).
Optimum biodiesel was obtained on a catalyst of 1 g KOH/CaO with a catalyst weight of
1% by weight, a reaction time of 3 hours, a stirring speed of 500 rpm, a temperature of 60
°C and a mole ratio of oil : methanol 1:15 in the transesterification reaction stage. The
resulting yield is 96.82%. Optimum biodiesel has the following characteristics water
content 0.009% volume, specific gravity 883 kg/m3, viscosity 5.38 mm2/s, carbon residue
0.01% mass, acid number 0.42 mgKOH/g, saponification number 225.95 mgKOH /g, the
iodine number is 50.44 g-I2/100 g and the cetane number is 59.10. In general, the
characteristics of biodiesel are in accordance with SNI 7182 2015.
