Pretreatment of oil palm empty fruit bunch (OPEFB) by N-methylmorpholine-N-oxide (NMMO) for biogas production: Structural changes and digestion improvement

Purwandari, F. A., Sanjaya, A. P., Millati, R., Cahyanto, M. N., Horvath, I. S., Niklasson, C., Taherzadeh, M. J.

 

Pretreatment of OPEFB (oil palm empty fruit bunch) by NMMO (N-methylmorpholine-N-oxide) on its subsequent digestions was investigated. The pretreatments were carried out at 90 and 120°C for 1, 3, and 5h in three different modes of dissolution (by 85% NMMO solution), ballooning (79% NMMO solution), and swelling (73% NMMO solution). The total solid recovery after the pretreatment was 89-94%. The pretreatment process did not have a major impact on the composition of OPEFB, other than a reduction of ash from 5.4% up to 1.3%. The best improvement in biogas production was achieved by a dissolution mode pretreatment of OPEFB, using conditions of 85% NMMO, 3h, and 120°C. It resulted in 0.408Nm³/kg VS methane yield and 0.032Nm³CH₄/kg VS/day initial methane production rate, which correspond in improving by 48% and 167% compared to the untreated OPEFB, respectively.

Perlakuan awal OPEFB (minyak kelapa sawit biji kosong) oleh NMMO (N-methylmorpholine-N-oxide) pada pencernaan berikutnya telah diselidiki. Perlakuan awal dilakukan pada suhu 90 dan 120 ° C selama 1, 3, dan 5 jam dalam tiga cara pembubaran yang berbeda (dengan larutan NMMO 85%), balon (79% larutan NMMO), dan pembengkakan (larutan NMMO 73%). Total pemulihan padat setelah perlakuan awal adalah 89-94%. Proses perlakuan awal tidak memiliki dampak besar pada komposisi OPEFB, selain pengurangan abu dari 5,4% sampai 1,3%. Perbaikan terbaik dalam produksi biogas dicapai dengan perlakuan awal mode disolusi OPEFB, dengan menggunakan kondisi 85% NMMO, 3 jam, dan 120 ° C. Hasilnya 0.408Nm3 / kg VS metana dan laju produksi metana awal 0,032Nm³CH₄ / kg VS / hari, yang masing-masing meningkat 48% dan 167% dibandingkan dengan OPEFB yang tidak diobati.