Carbon capture using solid sorbents in fluidized bed
reactors has
attracted increasing attention. However, optimized design and operation
require excellent control over the gas–solid contact and sorbent
circulation between the adsorber and desorber reactors. In this study,
the hydrodynamics and CO2 capture process using potassium-based
solid sorbents in a full-loop integrated system consisting of a bubbling-transport
bed adsorber and a bubbling bed desorber are investigated by using
a three-dimensional two-fluid model (TFM), in which the operating
parameters can be realistically adjusted. Results show that the sorbent
circulation rate increases with the gas velocity in the central pipe
and with the static bed height in the bubbling section of the adsorber.
The pressure distribution, sorbent concentration, and distributions
of the gas and solid velocities are explored, and optimized gas velocities
in the bubbling section and the central pipe are recommended. The
CO2 capture efficiency increases as the water vapor concentration
in the inlet flue gas is increased from 8 to 18%, and the optimal
water vapor concentration is identified as 14%. The results of this
study are useful for the design and optimization of CO2 capture reactors with solid sorbents.