Studies of the fischer‐tropsch synthesis on a cobalt catalyst II. Kinetics of carbon monoxide conversion to methane and to higher hydrocarbons

Six Langmuir‐Hinshelwood‐Hougen‐Watson models have been derived for the kinetics of conversion of carbon monoxide to hydrocarbons in the Fischer‐Tropsch synthesis. The models were fitted to experimental data obtained in an internal recycle reactor over a wide range of operating conditions. Two models, one based on the hydrogenation of surface carbon and the other on a hydrogen‐assisted dissociation of carbon monoxide as rate limiting steps were both able to provide a satisfactory fit to the experimental rate data. A general model was also developed for the rate of methanation in the presence of higher hydrocarbons. The same two rate limiting assumptions as those used in formulating the rate of total CO conversion are used in these models. The two models were fitted to experimental data for methane formation. It was the model assuming CH formation as rate limiting that showed the best fit for both CO conversion for CH4 formation.