Simultaneous catalytic removal of NO_x, SO_x, and CO from FCC regenerator

Simultaneous catalytic removal of NO_x, SO_x, and CO under simulated FCC regenerator conditions was investigated over mixed oxide catalysts CuMgAlO (Cu-cat), CeMgAlO (Ce-cat), and CuCeMgAlO (CuCe-cat), which were prepared by coprecipitation and characterized by XRD, XPS, and N₂ adsorption-desorption. At low temperatures (<340 °C), the presence of O₂ or H₂O enhanced the activity of CuCe-cat for NO and CO conversion but significantly suppressed the activity of Cu-cat and Ce-cat. At high temperature (720 °C), the presence of O₂ or H₂O had no adverse effect on the NO and CO conversions over these catalysts. However, the presence of SO₂ in the feed deactivated Cu-cat and Ce-cat drastically while no deactivation of CuCe-cat was observed. The enhanced performance of CuCe-cat can be explained by a synergistic effect between copper and cerium ions, which results in the formation of large amounts of Cu⁺ ions and oxygen vacancies. Thermogravimetric studies show that this catalyst exhibits excellent performance for SO_x adsorption in the SO₂ + O₂ system and can effectively release the adsorbed SO_x in H₂ + Ar atmosphere.