关键词: Biocarbon, K₂CO₃, CO₂ sorption, Humid flue gas

Abstract: Solid sorbents with enhanced capacity and selectivity towards CO₂ are crucial in the design of an efficient capture process. Among the possible alternatives, K₂CO₃-doped activated carbons have shown high CO₂ capture capacity and rapid carbonation reaction rate. In this work, a sustainable and low-cost approach is developed with a biomass-based activated carbon or biocarbon as support. The CO₂ capture performance in cyclic sorption-desorption operation and the sorption kinetics have been investigated under different scenarios in a purpose-built fixed-bed set-up. Independent of the H₂O concentration in the flue gas, a constant relative humidity (~20%) in the K₂CO₃-doped biocarbon bed promoted the carbonation reaction and boosted the CO₂ sorption capacity (1.92 mmol/g at 50℃ and 14 kPa partial pressure of CO₂). Carbonation is slower than physical adsorption of CO₂ but wise process design could tune the operation conditions and balance capture capacity and sorption kinetics.

Key words: Biocarbon, K₂CO₃, CO₂ sorption, Humid flue gas