Carbon dioxide (CO2) is considered to be the major greenhouse gas contributing to global warming. While reducing fossil fuel consumption may provide the ultimate answer to CO2 emission problems, one of the short-term solutions is the separation and subsequent disposal of the CO2 from power plant and industrial flue gas streams. A novel, energy-efficient CO2 separation process known as the circulating fluidized bed pressure-temperature swing adsorber (CFB-PTSA) is simulated in this work. A hydrodynamic model for the gas and solids flow structure in the riser of circulating fluidized beds is combined with a competitive adsorption model for a carbon dioxide, nitrogen, oxygen mixture on a type X zeolite, as described by the ideal adsorbed solution theory, to predict the reactor performance. Simulations performed at various riser operating conditions and flue gas CO2 concentrations indicate that the CO2 recovery decreases with increasing concentration at a fixed solids circulation Bur, but the purity of the recovered product increases. Recoveries in the range of 65-88.5% and product purities of 75-90% CO2 are predicted.
