Analisis Sifat Fisika Kimia pada Penyimpanan Bahan Bakar B40 dengan Injeksi Ultrafine Bubble

Abstract

Ketergantungan Indonesia terhadap energi fosil mendorong penerapan kebijakan mandatori bahan bakar B40, yaitu campuran 40% biodiesel berbasis fatty acid methyl ester (FAME) dan 60% minyak solar, yang rentan mengalami degradasi oksidatif selama penyimpanan. Penelitian ini bertujuan menganalisis perubahan karakteristik fisika-kimia bahan bakar B40 meliputi densitas, viskositas kinematik, kandungan air, stabilitas oksidasi, dan bilangan asam total selama empat minggu penyimpanan setelah injeksi ultrafine bubble (UFB) dengan variasi waktu injeksi 0, 10, 20, dan 30 menit menggunakan oksigen berkonsentrasi 99% dan debit 3 LPM. Pengujian dilakukan di Balai Besar Pengujian Minyak dan Gas Bumi (LEMIGAS) berdasarkan metode ASTM. Hasil penelitian menunjukkan bahwa densitas dan bilangan asam total tidak mengalami perubahan yang signifikan akibat penambahan UFB. Viskositas meningkat pada waktu injeksi di atas 10 menit, sementara stabilitas oksidasi mengalami penurunan pada seluruh sampel dengan penurunan terbesar terjadi pada waktu injeksi 20 dan 30 menit. Kandungan air meningkat selama penyimpanan pada seluruh sampel, namun sampel dengan waktu injeksi lebih lama secara konsisten memiliki nilai kandungan air yang lebih rendah dibandingkan kontrol. Meskipun terdapat perubahan pada beberapa parameter, seluruh sampel B40 tetap memenuhi spesifikasi bahan bakar yang ditetapkan Kementerian Energi dan Sumber Daya Mineral setelah penyimpanan satu bulan.

Indonesia's dependence on fossil energy has encouraged the implementation of the mandatory B40 biodiesel fuel policy, consisting of a blend of 40% fatty acid methyl ester (FAME)-based biodiesel and 60% petroleum diesel, which is susceptible to oxidative degradation during storage. This study aimed to analyze changes in the physicochemical characteristics of B40, including density, kinematic viscosity, water content, oxidation stability, and total acid number, during four weeks of storage following ultrafine bubble (UFB) injection with injection times of 0, 10, 20, and 30 minutes using 99% oxygen at a flow rate of 3 LPM. Testing was conducted at the Research and Development Centre for Oil and Gas Technology (LEMIGAS) based on ASTM standard methods. The results showed that density and total acid number were not significantly affected by UFB addition. Kinematic viscosity increased at injection times exceeding 10 minutes, whereas oxidation stability decreased in all samples, with the greatest reduction observed at injection times of 20 and 30 minutes. Water content increased throughout the storage period for all samples; however, samples subjected to longer injection times consistently exhibited lower absolute water content values than the control sample. Despite changes in several parameters, all B40 samples remained within the fuel specifications established by the Ministry of Energy and Mineral Resources after one month of storage.