Methanol-to-gasoline chemistry was discovered by ExxonMobil scientists in the
1970s. Over years of extensive studies and pilot plant operations, ExxonMobil developed an understanding of the MTG reactions and process conditions necessary to consistently produce motor gasoline. In 1979, a fixed bed design was completed and thoroughly demonstrated at 4 BPD capacity (today proven scalable up to 15 KBD).
In this design, methanol is first dehydrated over an amorphous alumina catalyst to an equilibrium mixture of di-methyl ether (DME), methanol and water. The DME reactor effluent is introduced into the MTG reactors, wherein methanol and DME are completely dehydrated by a proprietary catalyst forming light olefins and water. At the MTG reactor conditions, light olefins oligomerize into higher olefins, which combine through various reaction paths into paraffins, naphthenes, and methylated aromatics. The shape-selective MTG catalyst limits the hydrocarbon synthesis reactions to about C₁₁.