Counteracting Catalyst Deactivation in Methane Aromatization with a Two Zone Fluidized Bed Reactor

Methane aromatization is a promising alternative for the transformation of natural gas to liquid products but Suffers the problem of a fast catalyst deactivation. The use of a two zone fluidized bed reactor (TZFBR) has been studied as a method to counteract this problem. In this reactor, two zones are created in a fluid bed by feeding the hydrocarbon at an intermediate point and a regenerating gas to the bottom of the reactor. A Suitable catalyst for operation in the fluid bed has been developed. The results show that the TZFBR provides, stable operation, thanks to the in situ regeneration of the catalyst ill the lower part of the reactor. Three regenerating agents have been tested: oxygen, water, and carbon dioxide. Steady state operation has been achieved with all of them, but the best selectivity to aromatic products (benzene, toluene, and xylenes) was obtained with carbon dioxide. A significant effect of the reactor shape was also observed. The conversion and selectivity achieved with this reactor appear among file best Values reported in the literature, with the advantage of being obtained at a steady state.