Jacek A. Lapszewicz

Study of mixed steam and CO2 reforming of CH4 to syngas on MgO-supported metals

Abstract The activity of mixed steam and CO 2 reforming of CH 4 to produce synthesis gas was investigated and compared with those of steam reforming alone and CO 2 reforming alone at 600–900°C under atmosphere pressure on MgO-supported noble metals. Mixed reforming shows a far lower CH 4 conversion than the value for thermodynamic equilibrium. The activity decreases following the order Ru,Rh > Ir > Pt,Pd. Little deactivation was observed for Ru, Rh and Ir catalysts. An isotope labelled 13 CO 2 experiment was carried out in situ for mixed reforming on Rh/MgO and the results suggest that CO 2 dissociates as CO-M and O-M. The results of the temperature program reaction (TPR) of mixed reforming shows that CH 4 adsorbs and dissociates before reaction starts and that CO 2 reforming and steam reforming start simultaneously. A possible reaction mechanism is discussed.

The effect of catalyst porosity on methane selectivity in the Fischer–Tropsch reaction

An examination of the relationship between the catalyst porosity and selectivity for methane formation in the Fischer–Tropsch reaction has shown that variation in product spectrum may be the result of changing adsorption patterns of hydrogen and carbon monoxide rather than mass transfer phenomena as previously thought.

Partial oxidation of methane to methanol-comparison of heterogeneous catalyst and homogeneous gas phase reactions

Abstract Potential catalysts for the partial oxidation of methane to methanol have been synthesised and tested in high pressure annular reactors. Uranium oxide and molybdenum oxide catalysts and iron sodalite catalyst have been tested under the conditions reported in the patents and under conditions which allow comparison with reactions carried out in the gas phase. None of the catalysts tested showed an improvement on the gas phase results. It was found that the oxidative nature of the metal oxide catalysts is an inherent feature which reduces the selectivity to methanol.

Origin of the low limits in the higher hydrocarbon yields in the oxidative coupling reaction of methane

Abstract A constant C 2+ concentration is reached in the catalysed oxidative coupling of methane when the rate of C 2+ formation from CH 4 is equal to its rate of conversion to CO x .

Methane adsorption on a working samarium oxide catalyst and its role in hydrocarbon formation during high temperature partial oxidation

Although methane is strongly adsorbed on a samarium oxide catalyst at 700 °C, the adsorbed form does not participate directly in the formation of the hydrocarbon products of the partial oxidation reaction.

Process Optimisation of the Catalytic Partial Oxidation of Methane to Synthesis Gas.

Publisher Summary The most common and industrially favoured method for converting natural gas to syngas at present is steam reforming, which involves a highly endothermic reaction, and as a result is an energy intensive and costly process. In addition, conventional steam reformers are unsuitable for off-shore or remote small-deposit application, because of their large size and appreciable capital cost. Partial oxidation of methane to syngas, using oxygen as oxidant, represents an alternative to steam and CO, reforming, as it is exothermic, more selective, and theoretically yields a H 2 :CO ratio of 2. However, with the recent development of a new generation of highly active catalysts that appear capable of producing syngas at relatively lower temperatures, there has been a flurry of renewed interest in the area of catalyst development. The discussion presented here focuses primarily on optimizing the process conditions in a fixed-bed reactor, using known highly active catalysts. The effect of temperature, space velocity, particle size, nitrogen diluent in the feed, co-feeding of steam, and pressure, on conversion and selectivity have been examined.

Catalytic Studies of Methane Partial Oxidation

A number of catalysts have been reported in patents and literature that are claimed to produce methanol at selectivities in excess of 75% by direct partial oxidation of methane. Investigations of potential catalysts for the heterogeneous direct conversion of methane to methanol have been undertaken.