(583ds) Fischer–Tropsch Synthesis: Development of Kinetic Expression for An Impregnated Fe–Mn/Al2O3 Catalyst

In the  last  few  years, the  world  energy  crisis,  cause to  renewed interest  in  the  Fischer–Tropsch  synthesis  (FTS) reaction.  The  Fischer–Tropsch  synthesis  is  the  heart  of  the  GTL  process, which  converts  natural  gas  (mixture  of  H₂ and  CO)  to  large  variety of  ultra  clean  olefin,  paraffin  and  oxygenate. An investigation was carried out to establish 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: 4500-7000  cm³ (STP)/h/g_cat). 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  data  of  this  study  were  fitted  precisely  by  a  kinetic form that assumed  the  following  kinetically  relevant  steps,  where CO dissociation is reversible and does not involve hydrogen. All hydrogenation steps are irreversible or the first hydrogenation step is slow and rate determining. The kinetic parameters were determined using Levenberg–Marquardt (LM) method.