Fischer-Tropsch on iron with H_2/CO and H_2/CO_2 as synthesis gases:the episodes of formation of the Fischer-Tropsch regime and construction of the catalyst.

摘要

Fischer-Tropsch synthess experimtns have been performed with reduced precipitated Fe-Al-Cu-K_2O catalysts,using a H_2/CO and a H_2/CO_2 synthesis gas.samples of the reaction products and of the catalyst were taken at distinct run lengths.Teh product sampels were analyzed in detail and from their composition the kinetic data of elemental reaction steps (growth,branching,desorption as olefin o r paraffin) calculated,applying the extendedmodel of "nontrivial surface polymerizaiton".The catalyst samples were characterizec by BET,XRD,Mossbauer spectroscopy,XPS and TPD in hydrogen and thus specifically phase hcanges of e.g.alpha iron,iron oxides,and inron carbides observed.It has been measured how the product composition changed iwth time,up to the steady state of synthesis.severa episodes with their own kinetic regimes were identified.These were hten correlated with compositional and structural changes of the catalyst.This is addressed as "construction of the true iron Fischer-Tropsch catalyst".