Uji Kinerja Alat Dehidrasi Bioetanol dengan Molecular Sieve Menggunakan Sistem Sirkulasi Batch

Abstract

Bioetanol merupakan salah satu sumber energi terbarukan yang berpotensi menggantikan bahan bakar fosil. Namun, proses distilasi konvensional hanya mampu menghasilkan bioetanol berkadar sekitar 95 % karena adanya fenomena azeotrop etanol air, sehingga diperlukan proses dehidrasi lanjutan menggunakan molecular sieve untuk memperoleh bioetanol berkualitas fuel grade. Penelitian ini bertujuan menganalisis pengaruh penggunaan pompa sirkulasi dengan variasi frekuensi 30 Hz, 35 Hz, 40 Hz, dan 45 Hz terhadap kinerja alat dehidrasi bioetanol sistem batch berbasis molecular sieve. Parameter yang diamati meliputi kestabilan suhu, laju aliran produk, kebutuhan daya, konsumsi energi, kadar etanol, volume produk, massa etanol, rendemen, dan Specific Energy Consumption (SEC). Hasil penelitian menunjukkan bahwa penggunaan pompa sirkulasi mampu menjaga suhu operasi lebih stabil, namun meningkatkan kebutuhan daya dari 2705,40 W menjadi 3361,23 W serta konsumsi energi dari 11714,38 Wh menjadi 23577 Wh pada frekuensi 45 Hz. Nilai SEC terendah diperoleh pada perlakuan tanpa pompa sebesar 17588,58 Wh/kg, sedangkan penggunaan pompa menghasilkan SEC sebesar 36103,98–42544,30 Wh/kg. Pengukuran menggunakan hidrometer menunjukkan kadar etanol tertinggi diperoleh pada perlakuan tanpa pompa sebesar 99,3 %, sedangkan penggunaan pompa menghasilkan kadar 98,6–98,8 %. Hasil uji kadar air metode Karl Fischer menunjukkan kadar etanol berkisar 98,38–99,17 %, namun seluruh perlakuan belum mencapai standar fuel grade etanol sebesar 99,5 %. Hasil penelitian menunjukkan bahwa penambahan pompa sirkulasi pada konfigurasi alat yang digunakan belum mampu meningkatkan kualitas bioetanol maupun efisiensi energi proses.

Bioethanol is one of the most promising renewable energy sources to replace fossil fuels. However, conventional distillation can only produce bioethanol with a purity of approximately 95 % due to the ethanol water azeotrope, making an additional dehydration process using a molecular sieve necessary to obtain fuel grade bioethanol. This study aimed to analyze the effect of using a circulation pump at frequencies of 30 Hz, 35 Hz, 40 Hz, and 45 Hz on the performance of a batch bioethanol dehydration unit employing a molecular sieve. The evaluated parameters included temperature stability, product flow rate, power requirement, energy consumption, ethanol concentration, product volume, ethanol mass, yield, and Specific Energy Consumption (SEC). The results showed that the circulation pump maintained a more stable operating temperature but increased the power requirement from 2705.40 W to 3361.23 W and the energy consumption from 11714.38 Wh to 23577 Wh at a pump frequency of 45 Hz. The lowest SEC was obtained in the treatment without a circulation pump, with a value of 17588.58 Wh/kg, whereas the pump assisted treatments produced SEC values ranging from 36103.98 to 42544.30 Wh/kg. Hydrometer measurements indicated that the highest ethanol concentration (99.3 %) was achieved without the circulation pump, while the pump-assisted treatments produced ethanol concentrations ranging from 98.6 % to 98.8 %. Karl Fischer water content analysis showed ethanol concentrations ranging from 98.38 % to 99.17 %; however, none of the treatments met the fuel grade ethanol standard of 99.5 %. Overall, the addition of a circulation pump in the applied system configuration did not improve bioethanol quality or the energy efficiency of the dehydration process.