The conversion of methanol to hydrocarbons is a remarkable reaction. The mechanism involves C-C bond formation from C1 fragments generated in the presence of certain acidic catalysts and reagents. The precise nature of these reactive C1 species is unknown at present and is the subject of lively debate. The considerable diversity of current opinion will become apparent from the following account.

Hydrocarbons from Methanol

The formation of coke during hydrocarbon transformations over acid zeolite catalysts has important practical consequences for a growing number of industrial processes. This review presents available material on the formation, nature and properties of coke in high silica zeolite catalysts, and on the resulting deactivation and regeneration of the catalysts. Techniques for analyzing and characterizing coke, the role of acid sites in coke formation and the chemistry of coke formation are discussed, with particular emphasis on the methanol to gasoline process.

Coke formation in high-silica zeolites

Conversion of methanol over ZSM-5 to fuels and chemicals

A study has been made of the activity recovery of H-ZSM5 zeolite based catalysts, which have been used in reaction-regeneration cycles in the transformation of methanol into gasoline. Catalyst stability is sensitive to catalyst calcination conditions (temperature and time) and to zeolite Si/Al ratio. From experiments carried out on automated reaction-regeneration equipment provided with an isothermal fixed-bed reactor, optimum catalyst equilibration conditions have been determined, in order to minimize the irreversible deactivation in the regeneration step. The effect of this step on the catalyst acid structure has been studied.

Catalyst Equilibration for Transformation of Methanol into Hydrocarbons by Reaction−Regeneration Cycles

Mobil recently commercialized its fixed-bed methanol-to-gasoline (MTG) process in a 14, 500 B/D (gasoline) plant, based on natural gas, which is located in New Zealand. Process development studies were carried out in a small pilot plant to define conditions for producing gasoline in good yield and with acceptable product quality while also insuring satisfactory catalyst life. The process was successfully scaled-up by a factor of 100 to a demonstration unit size of 4 B/D. The scale-up factor from the demonstration unit to the commercial plant was in excess of 3000. The characteristics of the fixed-bed MTG process, its development, scale-up to demonstration unit, and assurance of acceptable product quality are discussed.

Sergel Yurchak

Papers

Process Aging Studies in the Conversion of Methanol to Gasoline in a Fixed Bed Reactor