Mechanism and experimental study of desulfurizing agent based on Mn/Ce-Ca for sintering flue gas desulfurization (FGD)

A novel Mn/Ce-Ca-based desulfurizer was prepared by dipping-roasting method to improve the performance of single calcium hydroxide (Ca(OH)2) for sintering flue gas desulfurization (FGD) at 100–350 ℃. In this study, metal dopants iron oxide (Fe2O3) and magnesium oxide (MgO) are added to improve the microstructure of single Ca(OH)2 and enhance the utilization of active components. The experimental results on the fixed bed showed that the desulfurization performance got best when the ratio of Fe2O3 to MgO was 3:2, the dipping times of desulfurizer were two, the temperature was 350 ℃, and the oxygen content was 5%. Meanwhile, the effect of H2O content was also studied. Great desulfurization ability with a removal efficiency of 100%, sulfur capacity of 69.95 mg/g, and breakthrough time of 76 min was achieved by desulfurizer 3F2M–3MC-Ca. Even at a low temperature of 100 °C, the sulfur capacity of the desulfurizer is three times higher than that of single Ca(OH)2, confirming its advantages in low-temperature desulfurization. Moreover, the reaction mechanism is systematically elaborated via the kinetic, diffusion, and thermodynamic calculations, and the characterization of this desulfurizer is studied by XRD, SEM, BET, XPS, and ICP-OES. Results show that the addition of Mn/Ce significantly enhances the activity of the desulfurizer by providing abundant oxygen vacancies during the reduction reaction. The work presented here has profound implications for future studies of the low-temperature dry sintering flue gas desulfurization field. Finally, the potential application of this technology is discussed to demonstrate the industrial application value.