Catalytic performance of an iron-based catalyst in Fischer–Tropsch synthesis

This paper documents the performance and kinetics of an iron/manganese oxide catalyst in a fixed-bed reactor by Fischer–Tropsch synthesis (FTS) under conditions favoring the formation of gaseous and liquid hydrocarbons (P: 1–12 bar; T: 513–543 K; H2/CO:1, 1.5, 2 mol/mol; gas hourly space velocity: 4200–7000 cm3 (STP)/h/gcat). Based on the hypothesis that water inhibits the intrinsic FTS reaction rate, eight kinetic models are considered: six variations of the Langmuir–Hinshelwood–Hougen–Watson representation and two empirical power-law models. The kinetic expression/mechanism that most precisely fits the data assumes the following: (1) CO dissociation is reversible and does not involve hydrogen; (2) all hydrogenation steps are irreversible, or the first hydrogenation step is slow and rate determining. Also, the performance of the catalyst for FTS and the hydrocarbon product distributions were investigated under different reaction conditions.