Techno-economic analysis of biomass processing with dual outputs of energy and activated carbon

Biomass utilization is facing great challenge mainly due to the low profit margin of biomass products. Bio-energy plants using gasification and liquefaction technologies are barely surviving, while biomass to activated carbon (AC) route has been demonstrated economically successful. In this work, spent mushroom substrate was used to produce AC and fuel gas with two different processes using internal flue gas and external air as activation agents, respectively. Experimental work was conducted to produce input data for Aspen Plus simulation including processing temperature, flue gas composition, AC yield, etc. Techno-economic analysis was performed, which reveals a great economic potential of integrating AC production in biomass processing. Air activation has obvious advantage in economic benefits, while the risk of precise temperature control and operation stability needs to be carefully evaluated in large-scale production. Flue gas activation is more reliable and it also generates less CO₂ that is beneficial for the long-term operation.