Aromatization of methane with combination of catalysts

#The present invention relates, in some aspects, to processes and systems for aromatization of low hydrocarbons, including production of aromatic hydrocarbons from natural gas.

#It is known that dehydroaromatization of methane (CH4) under non-oxidative conditions is thermodynamically more favorable to aromatics than to olefins, and molybdenum-modified zeolites or aluminosilicates such as Mo/ZSM-5 and Mo/MCM-22 are found to be effective catalysts for such reactions. Extensive research on the performance of such catalysts has been conducted and reported, and it has been found that the production performance depends on the structure and composition of the catalyst tested and how the catalyst is activated. Thus, research reported to date has focused on identifying a catalyst that can be activated to provide improved aromatization performance such as benzene yield from methane aromatization.

#Representative publications of such research results include:

#In the figures, which illustrate, by way of example only, embodiments of the present invention,

#FIG. 1 is a schematic diagram of an aromatization process using a reactor, exemplary of an embodiment of the present invention;

#FIG. 2 is a schematic sectional view of a reaction zone of the reactor of FIG. 1; and

#A process for producing aromatic hydrocarbons from a reaction gas containing methane according to selected embodiments of the present invention is illustrated in FIG. 1. As shown, the reaction gas is fed to a reactor 10, in which the reaction gas may be heated under non-oxidative conditions to produce aromatic hydrocarbons and other products such as hydrogen.

#The reaction gas may be a natural gas. Typical natural gases may include, e.g. 75 to 99 mol % of methane (CH4), 0.01 to 15 mol % of ethane (C2H6), 0.01 to 10 mol % of propane (C3H8), up to 0.30 mol % of carbon dioxide (CO2), and other minor components. The reaction gas may also be any other synthesized or naturally existing gases or mixtures of gases that contain low carbon alkanes, or other low carbon aliphatic hydrocarbons, such as C1-C4 hydrocarbons.

#The actual reactions occurring in reactor 10 may be complicated and may vary in different embodiments depending on various factors as can be understood by those skilled in the art. In many instances, the complete reaction mechanisms may not be completely understood. However, the overall reactions may include a reaction result that can be described as: 6CH4=9H2+C6H6.  (1)