Methane conversion processes

In this work, we will show that the addition of TCM to the feedstream in the methane conversion process results in the enhancement of the conversion of methane and the selectivity to C2 hydrocarbons on praseodymium oxide primarily as a result of the formation of praseodymium oxychloride, in contrast with the production of carbon oxides on praseodymium oxide in the absence of TCM (8-10). The surface properties of these catalysts are characterized by application of adsorption experiments and X-ray photoelectron spectroscopy (XPS). 

The industrially important direct methane conversion processes comprise oxidative coupling, reductive coupling including pyrolysis reactions, partial oxidation, halogenation and oxyhalogenation,26 and ammoxidation. Other direct conversions include alkylation, electrophilic substitution, and C-H bond activation over various complex and super acid catalysts. Several of these direct conversion technologies remain to be exploited to achieve their full commercial potentials. 

Fox, J. M., Chen. T. P, and Degen, B. D., Direct Methane Conversion Process Evaluation, Final Report, U.S. Department of Energy Contract DE-AC22-87PC79814, August 1988. 

The partial introduction of lead as cations in the hydroxyapatites shifts the methane conversion process to favour oxidative coupling products (Fig. 2). 

The production of higher hydrocarbons directly from methane by catalytic oxidative coupling is a novel methane conversion process which warrants further study. When combined with an ethylene oligomerisation step it is a potential alternative to conventional processes, based on synthesis gas, for producing liquid fuels from methane. However, further research is necessary to provide the information required to assess the commercial prospects for this route. 

The application of heterogeneous catalysts to the methane conversion process has recently been examined by Lunsford (ref. 9) with MgO and Mo/Si02, Somorjai (ref. 10) with Mo/Si0 2 and V/SiO2 and Sofranko (ref. 11), the latter of whom has examined various supported oxides for the oxidative coupling of methane. 

Numerous direct methane conversion processes can be divided into four groups ... 

Kuo, J.C. W. (1992) Chapter 15. Engineering Evaluation of Direct Methane Conversion Processes , in E.E. Wolf (ed.), Methane Conversion by Oxidative Processes, Van Nostrand Reinhold Catalysis Series, Van Nostrand Reinhold, New York, NY. 

In other words, a direct methane conversion process should have a C02-yield substantially lower than 20 C-atom % in order to represent a break-through compared to the indirect route. 

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