Kinetic Studies of CO2 Capture Using K2CO3/Activated Carbon in Fluidized Bed Reactor

In the present work, the capture of CO2 by the low-temperature solid sorbent K2CO3 coated on activated carbon in a fluidized bed reactor is studied. A 30 wt % of K2CO3 coated on activated carbon prepared by a wet impregnation method and characterized by SEM, EDX, and BET analyses is used as the sorbent. The pressure drop characteristics of the fluidized bed are studied using a humidified mixture of air and CO2 as the fluidizing medium to identify the minimum fluidization velocity. The minimum fluidization velocity increases with an increase in CO2 concentration and sorbent particle size and a decrease in temperature. Kinetic studies of CO2 capture are carried out in the fluidized bed reactor by directly measuring the solid conversion as a function of time. The experimental results show that the conversion of K2CO3, for a given time, increases with increase in CO2 concentration, fluidization velocity, temperature, and the height of the static bed, and decreases with the increase in sorbent particle size. The model proposed by Avrami for noncatalytic gas solid reactions is modified and fitted for the kinetic studies which satisfactorily predict the experimental data.