Proses transesterifikasi in situ bungkil wijen (Sesame Cake) untuk produksi biodiesel; pengaruh konsentrasi katalis Naoh dan suhu

Oleh :
Silviani Maria Wijayanti - H0606031 - Fak. Pertanian

RINGKASAN Peningkatan konsumsi bahan bakar minyak khususnya minyak solar merupakan salah satu masalah utama ketersediaan energi di Indonesia, ditengah menurunnya produksi minyak mentah secara alami. Salah satu bahan baku yang dapat digunakan sebagai biodiesel adalah bungkil wijen, karena bungkilnya masih mengandung minyak cukup tinggi sekitar 19,6 - 28,82 %. Biodiesel dihasilkan melalui proses transesterifikasi in situ dengan menggunakan katalis NaOH. Perlakuan pada penelitian ini adalah variasi penggunaan katalis NaOH (2%-b, 3%-b dan 4%-b) dan suhu proses (270 C dan 600 C). Kemudian dilakukan analisis terhadap rendemen, massa jenis, viskositas kinematik, angka asam, angka penyabunan, gliserol total dan kadar metil ester biodiesel bungkil wijen. Penelitian ini menggunakan rancangan acak lengkap (RAL) dan selanjutnya data dianalisis secara statistik dengan ANOVA, apabila hasil yang diperoleh ada beda nyata maka dilanjutkan dengan uji DMRT. Hasil penelitian menunjukkan biodiesel bungkil wijen pada konsentrasi katalis NaOH 3% mempunyai rendemen, gliserol total dan kadar metil ester yang paling baik yaitu 12,64%-b, 0,06 dan 98,91%-b. Sedangkan massa jenis, viskositas kinematik, angka asam dan angka penyabunan tidak lebih baik jika dibandingkan dengan konsentrasi katalis NaOH 2%-b dan 4%-b, meskipun nilainya memenuhi SNI-04- 7128-2006. Tetapi angka asam biodiesel bungkil wijen pada semua variasi konsentrasi katalis NaOH tidak memenuhi SNI-04-7128-2006. Biodiesel bungkil wijen dengan variasi suhu 270 C mempunyai rendemen, massa jenis, viskositas kinematik, angka asam dan kadar metil esternya paling baik yaitu 12,50%-b, 881,94 kg/m³, 4,36 cSt, 0,81 mg KOH/g dan 98,87%-b. Sedangkan angka penyabunan dan gliserol total tidak lebih baik dibandingkan dengan suhu 600 C, meskipun nilainya memenuhi SNI-04-7128-2006. Biodiesel bungkil wijen dengan variasi konsentrasi katalis NaOH 3% pada suhu 270 C mempunyai rendemen dan kadar metil esternya paling baik yaitu 13,07%-b dan 99,48%-b. Sedangkan massa jenis, viskositas kinematik, angka asam, angka penyabunan dan gliserol total tidak lebih baik jika dibandingkan dengan variasi konsentrasi katalis NaOH dan suhu. Kualitas biodiesel bungkil wijen semua perlakuan memenuhi SNI-04-7128-2006 kecuali massa jenis dengan konsentrasi 4%-b pada suhu 600 C dan angka asam dengan perlakuan C1T2, C2T2, C3T1 dan C3T2 tidak memenuhi SNI-04-7128-2006. Kata kunci : biodiesel, bungkil wijen, katalis NaOH, transesterifikas i in situ, suhu SUMMARY The increasing of fuel consumption especially diesel fuel is one of main problem of energy availability in Indonesia while natural crude oil production is decreasing. One of raw material that is can be used as biodiesel is sesame cake, because its still contain high oil level approximately 19,6 - 28,82 %. Biodiesel was yielded through transesterification process in situ by using NaOH catalyst. Treatment in research was various usage of NaOH catalyst (2%-b 3%-b, and 4%-b) and process temperature (27°C and 60°C). Then the research continued with analysis to its randement, specific mass, kinematics viscosity, acid number, lathering/soaping number, total glycerol and ester methyl rate of sesame cake biodiesel. This research applied completely randomized design (CRD) and then data was analyzed statistically with ANOVA, if result obtained had significant difference hence continued with DMRT test. Result of research shows sesame cake biodiesel at concentration of catalyst NaOH 3% has rendement, total glycerol and best ester methyl rate that is 12,64%-b, 0,06 and 98,91%-b. While specific mass, kinematics viscosity, acid number and lathering number is not more good if it is compared to concentration of catalyst NaOH 2%-b and 4%-b, though its value fulfilling SNI-04-7128-2006. But acid number biodiesel sesame oil cake at all of various concentration of catalyst NaOH doesn't fulfill SNI-04-7128-2006. Biodiesel sesame oil cake with temperature variation 270 C has rendement, specific mass, kinematics viscosity, acid number and its ester methyl rate is best that is 12,50%-b, 881,94 kg/m³, 4,36 cSt, 0,81 mg KOH/g and 98,87%-b. While total lathering number and glycerol not more good is compared to temperature 600 C, though its value fulfilling SNI-04-7128-2006. Sesame cake biodiesel with various concentration of catalyst NaOH 3% at temperature 270 C has its rendement and ester methyl rate is best that is 13,07%-b and 99,48%-b. While specific mass, kinematics viscosity, acid number, total lathering number and glycerol not more good if it is compared to various concentration of catalyst NaOH and temperature. Quality of biodiesel sesame oil cake of all treatment fulfills SNI-04- 7128-2006 except specific mass with concentration of 4%-b at temperature 600 C and acid number with treatment C1T2, C2T2, C3T1 and C3T2 doesn't fulfill SNI-04- 7128-2006. Keyword: biodiesel, NaOH catalyst, sesame cake, transesterification in situ, temperature