Used cooking oil can be used as raw material for biodiesel, but the levels of free fatty acids (Free Fatty Acid, FFA) is quite high. It is necessary for pretreatment in the form of the adsorption process to reduce levels of FFA. This study aims to determine the optimal conditions of adsorption process and determine the quality of biodiesel produced from adsorption processes and transesterification. Natural zeolites are used as adsorbents activated beforehand using ammonium chloride, calcined and heated to obtain H-zeolite. Furthermore, the adsorption process optimization includes the time, the adsorbent concentration, temperature and particle size. The oil that is already in the adsorption catalyst is reacted with methanol and KOH to obtain biodiesel. The optimum adsorption conditions obtained at the time of 90 minutes, the concentration of H-zeolite 12%, temperature 90 ° C, and a particle size of 0.2 mm that can lower FFA levels from 3.2% to 1.1%. Biodiesel produced meets the quality requirements of SNI 04-7182-2006 with a water content of 0.02%, a density of 857.60 kg / m3, the acid value of 0.29 mg-KOH / g, iodine number 15.71, saponification 168 , 02 and cetane index of 75.62. Compounds contained in biodiesel are methyl 9-octadecanoic (49.45%), methyl heksadekanoat (20.79%), and methyl 9,12oktaekanoat 9.12 (18.87%). Keywords: Biodiesel, used cooking oil, adsorption, transesterification, H-zeolitDOI: http://dx.doi.org/10.15408/jkv.v2i1.3107

The scarcity of fossil fuel has led to the development of renewable energy sources, such as biofuel from plant oils. Jatropha curcas oil is one of the potential plant oil sources of biofuel. The conversion of Jatropha oil into biofuel can be achieved through catalytic cracking using the catalyst of Lampung natural zeolite. This study aimed to characterize the catalyst, to determine the optimum condition of the catalytic cracking process and to study the physicochemical characteristic of biofuel. The study was begun by activating Lampung natural zeolite, characterizing the catalyst, optimizing the catalytic cracking process and testing the biofuel. XRD result showed that the activated natural zeolite has a crystal structure, as suggested by the appearance of high-intensity peaks at 23.72º; 22.38º and 27.96º, which showed the generation of H-zeolite. Thermogravimetry analysis showed that H-zeolite started to decompose at 300 ºC with 7.4% mass reduction and has thermal stability up until 700ºC. The surface area of the zeolite was 53.2542 m2/g. The optimum condition for the cracking process was achieved at 375 °C for 2 hours and 5 % concentration of catalyst. The biofuel generated from this study consisted of 67.12 % gasoline (C5-C11), 11.87 % kerosene (C12-C15) and 21.01 % diesel (C16-C20). This biofuel has a density of 0.966 g/mL and pours point of 235°K.

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Crude biodiesel hasil transesterifikasi minyak goreng bekas dapat ditingkatkan kualitasnya melalui proses catalytic cracking menggunakan zeolit alam. Penelitian ini bertujuan untuk menentukan kondisi optimum proses catalytic cracking dan sifat fisika dan kimia biofuel yang dihasilkan. Reaksi dijalankan dalam reaktor dengan memvariasikan waktu (1, 2 dan 3 jam), konsentrasi katalis (3, 5 dan 7 %), ukuran partikel katalis (180, 250 dan 630μm) dan suhu reaksi (325, 350 dan 375°C). Kondisi optimum proses catalytic cracking crude biodiesel didapatkan pada : waktu  3 jam, konsentrasi katalis 7%, ukuran partikel katalis 180 μm dan suhu reaksi 375°C. Biofuel yang dihasilkan mengandung 6,26% fraksi bensin(C5-C11); 17,6% kerosin (C12-C15), 47,73% biodiesel (C16-C20) dan asam lemak 28,4%. Analisis sifat fisik menunjukan densitas 0,9631g/mL, titik tuang 12°C, titik nyala  49°C dan angka oktan 72,6. Kata kunci: catalytic cracking, crude biodiesel, angka oktan, biofuel. Crude biodiesel from transesterification of used cooking oil can be improved in quality through catalytic cracking using natural zeolite. This study aims to determine the optimum conditions for catalytic cracking and the physical and chemical properties of biofuels produced. The reaction was carried out in the reactor by varying the time (1, 2 and 3 hours), catalyst concentration (3, 5 and 7%), catalyst particle size (180, 250 and 630 μm) and reaction temperature (325, 350 and 375°C) . The optimum conditions for the catalytic cracking crude biodiesel process were obtained at: 3 hours, 7% catalyst concentration, catalyst particle size 180 μm and reaction temperature 375 ° C. The resulting biofuel contains 6.26% gasoline fraction (C5-C11); 17.6% kerosene (C12-C15), 47.73% biodiesel (C16-C20) and fatty acids 28.4%. Physical properties analysis showed density of 0.9631g/mL, pour point 12°C, flash point 49°C and octane number 72.6. Keywords: Catalytic cracking, crude biodiesel, octane number, biofuel.

Petroleum fuels are increasingly limited in resources making the theme of sustainable energy one of the top issues in the world. Used cooking oil is non-edible and can even be said to be waste, so its use as a fuel does not compete with food oil and has a calorific value that is almost the same as conventional fuel. The cracking process is carried out using a Zeolite catalyst that has been impregnated with Fe. Fe/Zeolite catalyst variations are 1%, 3%, 5%, and 7%, with sizes 60, 80 and 100 mesh, while the temperature variations are 250 o C and 350 o C. Whereas the dependent variable is time, which is 2 hours. The optimum results obtained with the greatest yield on the use of catalysts with a catalyst concentration of 3%, catalyst size of 60 mesh and a temperature of 350 o C. The physical test carried out was a specific gravity test that was equal to 0.8241 at the optimum yield with a catalyst concentration of 3%, and 1.0392 on the use of a catalyst with a concentration of 5%. From the results of the GCMS test shows that the component that dominates the biofuel produced is gasoline seen from the C6 compound content of 17.2% and C8 of 13.7%. It can be said that the largest amount is biogasoline shown by the presence of C5-C11 compounds of 72.4% than biodiesel indicated by the percentage of C12-C15 of 24.1%.