Desulfurization Performance and Kinetics of Potassium Hydroxide-Impregnated Char Sorbents for SO2 Removal from Simulated Flue Gas

Potassium hydroxide-impregnated char sorbents (KOH/char) prepared via an ultrasonic-assisted method were used for SO 2 removal from flue gas. The desulfurization experiment was analyzed using a fixed-bed reactor under 40-150 °C temperature range, using simulated flue gas. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) were used to analyze both the chemical and physical characteristics of the sorbents. The analyzed results exposed that the complete elimination of SO 2 from flue gas was achieved when using the char/KOH sorbent with a mass ratio of char to KOH of 11:1. It was noted that temperature had a substantial influence on the desulfurization performance with sulfur capacity maximized at 100 °C. Experimental results also revealed that a small amount of O 2 present in the solvent could improve the SO 2 removal efficiency of the sorbent. The analyzed XRD patterns showed that K 2 SO 4 was the main desulfurization product, which was consistent with the SEM/EDS analysis. The experimental results were well-described with the Lagergren first-order adsorption kinetics model with the activation energy ( E a ) of the SO 2 adsorption by KOH/char sorbent of 20.25 kJ/mol.