Performance Evaluation of Accelerated Carbonation of Basic Oxygen Furnace Slag Via a Rotating Packed Bed: Modeling, Analysis and Maximization

Performance of accelerated carbonation by basic oxygen furnace slag (BOFS) in a rotating packed bed (RPB) was evaluated in this investigation.  The design of experiments (DOE) was introduced to evaluate the effect of different operating parameters including reaction time, particle size of BOFS, temperature, liquid-to-solid (L/S) ratio, and rotating speed on carbonation conversion of BOFS.  A quadratic response surface was established statistically to yield maximum carbonation conversion based on experimental data.  In addition, both the fresh and carbonated BOFS were characterized by the thermogravimetry and differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), and scanning electron microscopy equipped with X-ray energy dispersive spectroscopy (SEM-XEDS) to confirm the results of accelerated carbonation of BOFS in an RPB. 

Furthermore, by combining the process chemistry, reaction kinetics, and mass transfer, a prediction model for carbonation of BOFS within an RPB, with an error less than 10%, was well-developed.  The enhancement factors for mass transfer coefficient in case of carbonation of BOFS within an RPB were determined accordingly.  In comparison with the developed model and the RSM results, a standard operation procedure (SOP) was proposed for maximizing the carbonation conversion of BOFS.  It was thus concluded that the accelerated carbonation of BOFS using an RPB is a promising process for CO₂ capture due to its higher carbonation conversion achieving in a short reaction time.