(670g) Conversion of Fischer-Tropsch Light Hydrocarbons Over Ga-ZSM-5 to Assist in the Production of Fuels

Currently, synthetic fuel used for military purposes is created from a mixture of 50% petroleum-derived and 50% synthetically-created hydrocarbons.   The mixing of these two blends of hydrocarbons is required to meet the many fuel specifications required for military use.  The reformed, synthetic hydrocarbons produced by the Fischer-Tropsch (FT) process do not contain aromatic compounds.  In JP-8, aromatic compounds (typically C8-C16) are required to meet such properties as energy density and specific gravity.  Additionally, prior use of aromatic-containing JP-8 has made elastomers in the current fleet susceptible to leaking when introduced to a non-aromatic-containing fuel blend.  For these reasons, synthetic fuel produced currently requires the addition of single-ring aromatic compounds.

This work examines the synthesis of aromatic compounds from a model light gas stream available in a synthetic fuel plant.  The light gas stream in this plant would often be reformed to produce hydrogen or flared for heat duty.  However, using the catalyst Ga-ZSM-5, C6-C10 aromatics can be produced from light gases (C2-C6) in the presence of hydrogen, carbon monoxide, and carbon dioxide.  This work examines the potential aromatic yields that can be obtained from such a stream, and it examines the potential effects of carbon monoxide and carbon dioxide on the catalyst.  Finally, this work explores the additional step of converting from unreacted alkenes and C6-C10 aromatics to an aromatic spectrum that is appropriate for blending with FT synthetic fuel.