Nitrogen-rich natural gases as a potential direct feedstock for some novel methane transformation processes. Part 2: Non-oxidative processes

In this work (parts 1 and 2), we examined the chances for the future use of nitrogen-rich natural gases (NRNGs), without separation and nitrogen removal, as a direct feedstock in some novel CH₄ conversion processes. In part 1, the absence of the effect of the N₂ content in CH₄ on the course and results of such irreversible oxidative processes as methane oxidative coupling and methane and toluene oxidative crosscoupling were shown. In the present part 2, the possibility to useNRNGsas a direct feedstock in some nonoxidative processes of methane dehydroaromatization (MDA) to H₂ and aromatics and of methane catalytic decomposition (MCD) to H₂ and carbon was examined. Various CH₄-N₂ and CH ₄-N₂-(C₂-C₄) mixtures of different composition, modeling some degasolined, raw dry and wet NRNGs, containing up to about 80 vol%of N₂ were used in investigations. Experiments with C₂H₆-N₂, C₃H₈-N ₂, C₄H₁₀-N₂, and (C ₂-C₄)-N₂ mixtures were also performed. It was revealed that, in the reversible processes of MDAandMCD, procee ing with the increase in the number of moles, the increase in theN₂ concentration led to the rise in the CH₄ conversion and yields of desirable products, presumably because of the equilibrium shift. The effects of CH ₄ homologues on the yields of products and stability of the catalyst were also examined. It was concluded that NRNGs of different N₂ content and hydrocarbon composition (degasolined and raw dry and wet) can be considered in the future as a direct feedstock in both the oxidative and non-oxidative methane transformation processes. A demonstrated absence of specific technological obstacles for a direct use of non-separated NRNGs as a feedstock in the investigated novel processes indicated that their future industrial chances would only depend upon the results of the cost-effective analyses and the further advancement of novel processes.