Abstract:

The sorption kinetics of nano Ca-based CO₂ sorbents was investigated by thermogravimetric analysis（TGA）at 500—650℃ and N₂ atmosphere with 0.015—0.025 MPa CO₂ partial pressure. According to the characteristics of CO₂ sorption kinetics of nano Ca-based CO₂ sorbents，the sorption time point corresponding to two times of maximum sorption rate was proposed as the criterion to divide the sorption curve into rapid reaction section and slow reaction section. Boltzmann equation and Avrami-Erofeev equation were selected to simulate the kinetics of both rapid reaction section and slow reaction section. The activation energies were 27.52 kJ·mol^-1 and 70.25 kJ·mol^-1 respectively for the rapid reaction section and slow reaction section，with the mean average relative deviation of sorption ratio 10.29％，4.17% respectively. The decomposition kinetics of nano Ca-based CO₂ sorbents was experimentally studied also by thermogravimetric analysis（TGA）at 650—800℃ and three cases of N₂ atmosphere，0.02 MPa,0.04 MPa CO₂ partial pressure N₂ atmosphere. The decomposition kinetics equations were correlated by the shrinking core model by ignoring the effects of mass and heat transfer. The activation energies were 141.9 kJ·mol^-1，34.7 kJ·mol^-1 and 113.2 kJ·mol^-1 in the above three cases respectively，with the average relative deviation of decomposition ratio less than 5.66%，7.82% and 5.01% respectively.