Enhanced CO2 sorption capacity of amine-tethered fly ash residues derived from co-firing of coal and biomass blends

Co-firing of coal and biomass blends provides a promising route for clean energy utilization with high efficiency and mitigated pollutants emission. However, the technology meets an important challenge in effective utilization of the co-firing fly ashes. Efforts have been made to valorize the co-firing fly ash residues as potential CO 2 sorbents. To achieve enhanced CO 2 sorption performance, the samples were modified with tetraethylenepentamine (TEPA). Effects of amine loading, CO 2 sorption temperature, initial CO 2 concentration and gas flow rate on CO 2 sorption behaviors of the amine-tethered sorbents were investigated. The desired sorbent with 25% TEPA loading presented the highest CO 2 sorption capacity of 1.19 mmol CO 2 /g when tested under 60 °C and 15%CO 2 with a total gas flow rate of 1200 ml min −1 . The effects of regeneration temperature and ramping rate on sorbent regeneration performance were demonstrated. The maximum sorbent regeneration efficiency of 97.2% was achieved under the regeneration condition of 110 °C and 5 °C min −1 . CO 2 sorption capacity of the amine-tethered sorbent kept stable within 5 repeated cycles. These findings indicate that the amine-tethered sorbent could be a good candidate for on-site CO 2 capture from flue gas in co-firing power plants.