New silica-alumina-magnesia FCC active matrix and its possibilities as a basic nitrogen passivating compound

A vacuum gasoil has been cracked on USY containing catalysts in which the matrix is either an amorphous silica-alumina or an aluminium containing sepiolite. After steaming, the aluminous sepiolite containing catalyst is more active and selective than the silica-alumina one, and the former produces a gasoline with higher alkenes and lower aromatics content. When those catalysts were used to crack a vacuum gasoil containing 5000 ppm of basic nitrogen, the catalyst with the aluminous sepiolite was more efficient to trap the poisoning molecules, preserving the zeolite activity. It was confirmed by IR spectroscopy that the aluminous sepiolite removes higher amounts of basic nitrogen compounds than amorphous silica-alumina. With the high nitrogen containing feed, the sepiolite catalyst gives a higher cracking conversion, while it is more selective to middle distillates than the amorphous silica-alumina. Finally, in the presence of basic nitrogen the former gives a higher content of linear and branched alkenes in the gasoline fraction.