Some technological aspects of methane aromatization (direct and via oxidative coupling)

The investigations on transformation of methane to benzene and naphthalene have been carried out in aim to verify and supplement earlier reported data and on this basis to estimate real industrial perspectives of the CH4 aromatization concept, the main challenges and barriers. Methane aromatization (direct and via oxidative coupling) has been studied over Mo/HZSM-5 catalyst used both for direct methane dehydroaromatization and for aromatization of methane oxidative coupling (OCM) products. The effects of Mo content in the catalyst, temperature, space velocity, the presence of CO2, CO, H2O, C2H4, C2H6 and their mixtures in the feed have been studied. The effectiveness of the catalyst regeneration in the air was also examined. All results were confronted with the literature data and analyzed from technological point of view. It was confirmed that direct CH4 aromatization process was characterized by a low CH4 single-pass conversion, low single-pass yields of the main products (benzene, hydrogen and naphthalene) and a low catalyst stability (rapid catalyst deactivation). Various possible technological schemes were analyzed. It was concluded that real industrial chances of direct methane aromatization or aromatization via OCM would depend largely on the advancement in the cost-effective separation techniques. The methane aromatization concept was also confronted with other methane conversion processes.