Kinetic modeling of CO hydrogenation over a bimetallic Co/Ni catalyst in fixed bed reactor

An active Co-Ni/Al2O3 catalyst was prepared by impregnation method to synthesize light olefins in Fischer-Tropsch Synthesis. The kinetic experiment study was performed in a differential micro- fixed-bed-reactor by varying reaction temperature (230-270 °C), pressure (2-12 bar), gas hourly space velocity (2000-7200 h-1) and H2/CO feed molar ratio (1-3). Based on Langmuir– Hinshelwood–Hougen–Watson (LHHW) approach, seven different two-parameter kinetic models were considered. The kinetic data of this study were fitted fairly well by a simple form that assumed the following kinetically relevant steps: CO dissociated via interaction with adsorbed H; the first hydrogenation of surface carbon step was reversible and fast, while the second was slow and rate determining. The kinetic parameters were determined using Levenberg–Marquardt (LM) method and the apparent activation energy and heat of adsorption were 78.70 kJ/mol and -14.16 kJ/mol, respectively.

Keywords:

fischer-Tropsch synthesis , co , ni catalyst , micro-fixed -bed-reactor , kinetics