Gas to Liquids: Natural Gas Conversion to Aromatic Fuels and Chemicals in a Hydrogen-Permeable Ceramic Hollow Fiber Membrane Reactor

The performance of a dense ceramic hydrogen permeable membrane reactor for the nonoxidative methane dehydroaromatization (MDA), according to the equilibrium reaction 6CH(4) reversible arrow C6H6 + 9H(2) with a 6 wt % Mo/HZSM-5 bifunctional catalyst was investigated. A U-shaped ceramic hollow fiber membrane of the composition La5.5W0.6Mo0.4O11.25-delta (LWM0.4) has been used for the in situ removal of H-2 to overcome thermodynamic constraints. The yield of aromatics (benzene, toluene, naphthalene) in the MDA could be increased in the beginning of the aromatization reaction by similar to 50%-70%, in comparison with the fixed-bed reactor, because 40%-60% of the H2 abstracted have been extracted at 700 degrees C with a weight hourly space velocity (WHSV) of 840 cm(3) g(cat)(-1) h(-1). These advantages of the membrane reactor operation decrease with time on stream, since the removal of H2 boosts not only CH4 conversion and yield of aromatics, but also catalyst deactivation by deposition of carbonaceous deposits. However, the catalyst system could be regenerated by burning the coke away with air.