Conversion of Fischer-Tropsch Hydrocarbons Over H-ZSM-5 and Ga-ZSM-5 for the Production of Fuels

Fischer-Tropsch (FT) catalysts have long been used for hydrocarbon production from synthesis gas.  The product spectrum primarily consists of straight-chained alkane and alkene compounds beginning with methane and ending with the production of heavy waxes.  The average carbon number of the products is determined by the operating conditions and catalyst chosen.  For certain applications, the absence of aromatic compounds is preferred.  However, for certain fuels to meet required standards, the aromatic volume percentage must exceed that which can be produced by an FT reactor.

H-ZSM-5 and Ga-ZSM-5 catalysts have the ability to increase the branched hydrocarbon and aromatic composition of a hydrocarbon stream produced from an FT reactor system. Hydrocarbons too heavy to be used in fuels can be cracked over H-ZSM-5 located within or downstream of an FT reactor.  Ga-ZSM-5 catalysts can be used to upgrade undesired C2-C4 alkanes and alkenes into aromatic compounds in a downstream reactor.  This work explores the combination of multiple reactor beds used in series for the potential production of fuels from synthesis gas, and the effect of the inorganic gases present in this stream on the aromatization reactions.