Structure and properties of MgAlCuFe complex oxide for FCC desulfurization: effect of Fe and Cu contents

A series of MgAlCuFe complex oxides with various Fe and Cu contents used for the removal of SO_x from FCC flue gas were prepared by calcinaiion of MgAlCuFe hydrotaleite precursors at 700°C for 6 h. The influence of metal contents in the sulfur transfer catalyst was investigated by X-ray diffraction, N₂ adsorption, and X-ray fluorescence spectrometer analysis. The results show that all the sulfur transfer catalysts exhibited a better dispersion of metal oxides in the matrix. The results of S02 adsorption-reduction tests indicate that the catalyst Cu 1%Fe8%-LDOs had a total saturation adsorption capacity of 1.57 g/g in 6 min and a large reductive capacity under the conditions similar to those of a typical FCC. In the MgAlCuFe-LDOs, Fe played a dual role as an oxidizing and a reducing promoter, and Cu was an efficient promoter for oxidizing SO₂ to SO₃.