DESIGN OF CIRCULATING FLUIDIZED BED REACTOR FOR CARBON DIOXIDE ADSORPTION AND SORBENT REGENERATION

Abstract

Suitable height of the riser is a crucial design parameter for operating in circulating turbulent fluidized bed regime (CTFB). It was suggested to be lower than the maximum bed expansion. The hydrodynamics of the CTFB are similar to the conventional turbulent fluidized bed which has highly uniform solid fraction while particles can circulate throughout the system as the fast fluidization. The optimum sorption temperature was found to be 60 °C where the maximum CO2 capture capacity was 295.79 milligram of CO2 per gram of the sorbent which loaded by 17 percentage of K2CO3. The used sorbent could be regenerated by either heat treatment or depressurization. Thus, the lab scale circulating fluidized bed reactor was built to study the effect of the operating parameters. The positive trend of the increasing in gas velocity showed the promise trend for the commercial use. The sorption stages of the pilot scale were determined by computational fluid technique. The alternative design suggests a riser with 1 m in diameter and 3.55 m tall with cooling tubes being set to overcome the equilibrium limitation. The optimum cooling temperatures could provide more than 95% CO2 capture of the inlet concentration. This riser does not need a large amount of energy for regeneration as conventional amine absorber.