The State of Modifying Additives in Iron-Containing Zeolite Catalysts and of Coke Deposits Formed on Them During the Conversion of Straight-Run Gasoline

The state of iron-containing modifier additives (FeSiO₃, FeC, fly ash) in zeolite catalysts was studied by high-resolution transmission electron microscopy. The nature of the carbon compaction products formed on the modifier surface during the upgrading of the straight-run gasoline fraction of oil was elucidated. The modifier particles are uniformly distributed on the surface of the zeolite support, and the type of the modifying additive affects the structure and localization of coke formed on the catalyst surface. Carbon nanofibers mainly form on iron-free zeolite and on zeolite with a FeSiO₃ additive, and a layer of graphite-like carbon forms on zeolites with FeC and fly ash additions.