REMOVAL OF SO2 AND NO OVER RICE HUSK ASH (RHA)/CaO-SUPPORTED METAL OXIDES

Abstract

The activity of rice husk ash (RHA)/CaO-based sorbent supported with various metal oxides for the removal of SO2 and NO from simulated flue gas of combustion process has been studied. In this study, RHA/CaO-based sorbents were impregnated with an appropriate metal nitrates solution followed by drying and calcinations, which resulted in the sorbent having the following active phases; MgO, MnO, CoO, ZnO, Al2O3, Fe2O3, and CeO2. The sorbent-catalysts were tested in a fixed bed reactor by passing mixture gas consisting of SO2 (2000 ppm), NO (500 ppm), O2 (10 %), water vapor (50%) and N2 as a balance at a total flow rate of 150 mL/min and reaction temperature of 87C. The results showed that RHA/CaO sorbents impregnated with CeO2 displayed the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO2 and NO. Infrared spectroscopic results indicate the formation of both sulfate (SO42-) and nitrate (NO3-) species due to a catalytic role played by CeO2.

Keywords

• Rice husk ash (RHA)
• Metal oxides
• Sorbent-catalysts
• SO2
• NO