2 - Economic insights into the production of cellulose nanofibrils from oil palm biomass

Abstract

Cellulose isolation from lignocellulosic materials is a crucial step prior to cellulose nanofiber (CNF) production. In this present work, superheated steam and potassium hydroxide pretreatments are employed to treat oil palm mesocarp fiber, followed by mechanical fibrillation using wet disk milling. It is apparent that potassium hydroxide presented a higher hemicellulose removal efficacy than superheated steam by ~ 30%. The study also found that the remaining hemicellulose in superheated steam-treated fiber has an advantage in nanofibrillation, where it helped in the formation of smaller diameter fiber. The superheated steam-treated CNF contained ~ 84% fiber proportion with an average diameter of 20–40nm than ~ 60% in potassium hydroxide-treated CNF. This elucidates the role of hemicellulose in avoiding coalescence of delaminated cellulose fibers after mechanical fibrillation, known as hornification. Economically, the operating cost of CNF production by superheated steam—wet disk milling is valued at USD 55.6 per kg, well over potassium hydroxide—wet disk milling at USD 48.9 per kg. As the selling price is set at USD 240.62, the gross profit projected in a one-year operation for superheated steam and potassium hydroxide pretreatment is USD 103.3 thousand and USD 109.9 thousand, respectively. Positive net present values and high internal rate of returns manifest that both pretreatments employability are lucrative and expected to generate satisfactory revenue growth.