Mapping the methanol-to-gasoline reaction in a fluidized bed reactor.

Spray drying was used to prepare shaped H-ZSM-5/kaolin/alumina catalysts with different silica-to-alumina ratios, and their performance was mapped in MTG under fluidized-bed conditions. Catalyst shaping preserved the zeolitic structure while decreasing surface area and modifying the acid-site distribution relative to the parent zeolites. Fixed-bed testing showed that the shaped HZ-80(S) catalyst retained comparable methanol conversion and gasoline-range selectivity to the parent H-ZSM-5, while altering the distribution of light hydrocarbons and aromatic species. Under fluidized-bed operation, the silica-to-alumina ratio strongly affected the balance between activity, stability, and gasoline-range hydrocarbon formation. For instance, HZ-23(S) deactivated rapidly, HZ-280(S) showed high dimethyl ether slip due to insufficient acidity, and HZ-80(S) provided the most favorable compromise. Mapping the effects of methanol partial pressure, temperature, and weight hourly space velocity for HZ-80(S) revealed temperature as the dominant variable controlling gasoline-range yield, with a significant temperature-space velocity interaction. A maximum gasoline-range yield of 60.7% was achieved at 400 °C and 8 h-1, whereas operation at 400 °C and 16 h-1 maintained high productivity while reducing the aromatic content of the gasoline fraction.