Adsorption of CO2 on a confined fluidized bed of pelletized 13X zeolite

Abstract

The paper presents the results of an investigation into CO2 adsorption by a fluidized bed of pellets of 13X zeolite. The experiments compare the performance of a confined and that of a conventional fluidized bed using the same apparatus at ambient temperature and pressure. The effect of CO2 concentration in the inlet air stream, superficial gas velocity and particle size of the fluidized sorbent is analysed with reference to gas streams in which the fraction of carbon anhydride is that typical of a flue gas. The effectiveness of CO2 adsorption is assessed in terms of moles of CO2 adsorbed per unit mass of sorbent, breakthrough time and fraction of bed utilized at the breakpoint. Along with the increase of the adsorbed mass of CO2, it is found that the increment of the breakthrough time is roughly equal to 70%, while the increase of the fraction of bed utilized is always about 30%. Furthermore, in the confined fluidized bed the increase of temperature associated to adsorption is more limited and can be controlled by regulating the superficial gas velocity.The results obtained demonstrate that confined fluidization improves the efficiency of the adsorption process thus constituting a valid alternative to the conventional technique.