CO₂ removal in power systems using calcium-based sorbents ...

• Main Author: Sun, Ping
• Format: Text
• Language: English
• Published: University of British Columbia 2011
• Subjects: Arctic
• Online Access: https://dx.doi.org/10.14288/1.0059000; https://doi.library.ubc.ca/10.14288/1.0059000

Bench scale studies were carried out, focusing on the application of calcium-based sorbents in fossil-fuel-fired combustion and gasification systems, with conditions ranging from atmospheric to elevated pressures and at practical combustion and gasification temperatures. In the kinetic study of CaO carbonation, the reaction order changed abruptly from first- to zero-order when the CO₂ partial pressure exceeded the equilibrium value by more than ~10 kPa. A Langmuir mechanism successfully explained the experimental information, with the intermediate complex CaO•CO₂ postulated to saturate CaO sites immediately at high CO₂ partial pressure. The activation energies for rate constants were found to be 29 ± 4 kJ/mol and 24 ± 6 kJ/mol for Strassburg limestone and Arctic dolomite, respectively. A discrete-pore-size-distribution-based model was formulated, with the aid of which the kinetic study was extended to obtain diffusivities through the solid product layer formed during carbonation, with activation energies of ...