CO2 capture in a multistage CFB: Part I: Number of stages.

The most common technology for postcombustion of CO₂ capture is the amine solvent scrubber. The energy consumption for capturing CO₂ from flue gases using amine solvent technology is 15-30% of the power plant electricity production. Hence, there is a need to develop more efficient methods of removing CO₂. A circulating fluidized bed using sodium or potassium carbonates is potentially such a process, as their high decomposition pressures allow regeneration at low temperatures using waste heat rather than steam from the power plant. But equilibrium data for the sorbents require the use of several cooled stages to achieve high CO₂ conversions. Here, a method of computing such a number of stages for a given CO₂ conversion was developed using multiphase computational fluid dynamics. It was found that it required six equilibrium stages to remove 96% of CO₂ with the initial mole fraction of 0.15 in a sorption riser. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5267-5279, 2017 [ABSTRACT FROM AUTHOR]