Evaluation of Energy Consumption and Greenhouse Gas Emissions in Preparation of Cellulose Nanofibers from Woody Biomass

Life Cycle Assessment of Forest-Based Products: A Review

“…Sun et al [116] assumed a CNF yield of about 80% to 92% of woody biomass and energy usage was much lower than other studies with no chemical inputs. The MiLCA, a Japanese LCA support system-supported by a database, the IDEA (Inventory Database Environmental Analysis) was developed by the National Institute of Advanced Industrial Science and Technology (AIST) and the Japan Environmental Management Association for Industry (JEMAI) [116]-to perform LCAs. GW impacts of CNF estimated by Sun et al [116] and Moon et al [117] were 1.2 to 3.7 and 5.7 to 7.6 kgCO 2 e/kg of CNF, respectively, which were in the range of results produced by Hohenthal et al [114].…”

“…However, most studies consider pulp (kraft pulp or sulfite pulp) as feedstock to produce nanocellulose. Nanocellulose production from woody biomass requires a pulping process to dissolve lignin and hemicellulose [116,117]. Production of nanocellulose (without pre-treatment) is an energy-intensive process, where a large amount of electricity (~27 kWh/kg of nanocellulose) is consumed to break down the crystalline structure of cellulose and defibrillate individual fibers [113,122].…”

“…Without pre-treatment of pulp, microfibrillated cellulose (MFC) produced from kraft pulp or sulfite pulp requires about 12 to 70 and 27 kWh/kg of MFC, respectively [113]. Thermo-mechanical [116,117], chemical [115,118,119] and enzymatic [115,121] pre-treatments were proposed to pretreat the pulp/woody biomass to help free up the nanofibers and thus reduce the energy required in the process of nanocellulose extraction. The pre-treatment process (carboxymethylation and enzymatic) can drastically reduce the energy requirement of MFC production (0.5-1.5 kWh/kg of MFC) [113].…”

“…Pulp production is an energy-intensive process with large environmental impacts. In the Japanese nanocellulose LCA, Sun et al [116] and Moon et al [117] evaluated CNF production from woody biomass considering combined wet disk milling and mild hot-compressed water (HCW) treatment. In the HCW treatment, the acetyl groups of hemicellulose and water itself act as acids, which dissolve both hemicellulose and lignin in woody biomass [123].…”

“…In the HCW treatment, the acetyl groups of hemicellulose and water itself act as acids, which dissolve both hemicellulose and lignin in woody biomass [123]. Sun et al [116] assumed a CNF yield of about 80% to 92% of woody biomass and energy usage was much lower than other studies with no chemical inputs. The MiLCA, a Japanese LCA support system-supported by a database, the IDEA (Inventory Database Environmental Analysis) was developed by the National Institute of Advanced Industrial Science and Technology (AIST) and the Japan Environmental Management Association for Industry (JEMAI) [116]-to perform LCAs.…”