Catalytic partial oxidation of methane at industrially relevant conditions

In order to utilize a larger part of the world's natural gas reserves it is of interest to find a way to economically convert it to liquid fuels. Direct conversion has been elusive for decades and conversion therefore goes through the formation of syngas. Catalytic Partial Oxidation (CPO) is a potential technology for this. The process runs autothermally and with short residence times (10-50 milliseconds) with high yields of syngas from methane.; This thesis investigates different aspects of CPO of methane over Rhodium catalyst supported on foam monoliths. A newly developed technique that allows sampling inside the catalyst at operating conditions has shed new light on the process first reported over 15 years ago. The technique is based on inserting and moving a small quartz capillary inside the catalyst. It is thus possible to follow the evolution of gases, using a mass spectrometer with spatial resolution of 300--400 mum.; One of the aspects researched is the effect of sulfur poisoning on CPO of methane. It is shown that 14 ppm of CH3SH causes a temperature increase of over 200 °C due to a significant impact on the endothermic steam reforming, which causes a significant drop in syngas yield. The poisoning is reversible when CH3SH is removed from the feed. By extending an existing model for CPO of methane a 108 reversible step model was shown to capture the important features of sulfur poisoning.; Downstream processes that convert syngas to methanol or higher alkanes will run above atmospheric conditions; it is therefore of interest to see how pressure affect the CPO. Using the spatial technique spatially resolved profiles has been obtained at pressures up to 1.1 MPa. A comparison between Rh and Pt showed that CPO of methane over Rh is mass transfer limited and thus does not change with pressure at constant mass flow rate. On Pt the data showed signs of kinetic limitations.