In-situ Synthesis and Catalytic Properties of ZSM-5/Rectorite Composites as Propylene Boosting Additive in Fluid Catalytic Cracking Process

Using rectorite extrudates from calcined rectorite powder as the starting material, a series of ZSM-5/rectorite composites were prepared via the in-situ crystallization method. The physicochemical properties and propylene boosting performance of the resulting samples were characterized by using X-ray diffraction, scanning electronic microscopy/energy dispersive spectrometer, N-2 adsorption-desorption, and Fourier transformed infrared spectroscopy of pyridine adsorption, respectively, and assessed by using Daqing atmospheric residue as feed-stock. The results showed that the ZSM-5/rectorite composites in which the ZSM-5 phase grows in-situ as a 2-3 mu m thick layer on rectorite particles have a trimodal microporous-mesoporous-macroporous structure and thus exhibit outstanding propylene boosting performance. Compared with a commercial ZSM-5 incorporated fluid catalytic cracking catalyst, the ZSM-5/rectorite composite incorporated catalyst increased the yield and selectivity of propylene by 2.44% and 5.35%, respectively.