Influence of carbon deposits on Fe-carbide for the Fischer-Tropsch reaction

A well-known observation in the Fe-catalyzed Fischer-Tropsch (FT) reaction is that Fe-carbide catalysts deactivate due to carbon deposition. In comparison, influence of such deposits on product distribution has been less widely reported. The present work investigates relationship between kinetics FT for a carburized Raney-Fe model catalyst and composition catalytic surface with focus deposits. deposition during ongoing at low pressure decreases activity increases CH4 selectivity. Steady-state transient isotopic kinetic analysis (SSITKA) shows buildup C affects fast CO conversion sites surface, mainly responsible CC coupling via Langmuir-Hinshelwood mechanism, more than slow produce Mars-Van Krevelen mechanism. Hindrance migration chain-growth monomers by amount longer hydrocarbons. Nevertheless, SSITKA C2 products form faster, which likely since their formation increasingly depends formed proximate dissociation when increases. Carbon can be suppressed reversed increasing H2/CO ratio constant or total ratio. As such, performance stabilized operating elevated pressure, even if initially was started pressure. prolonged operation leads reactive character cannot removed anymore high-pressure operation.