METHANOL-TO-GASOLINE VS DME-TO-GASOLINE .2. PROCESS COMPARISON AND ANALYSIS

Methanol can be converted into gasoline boiling range hydrocarbons ove r zeolite ZSM-5 catalyst using the Mobil MTG process. Methanol feed in the MTG process can be derived from coal or natural gas based syngas. The Mobil MTG process involves the conversion steps of syngas-to-meth anol and methanol-to-gasoline. Dimethyl Ether (DME), a product of meth anol dehydrocondensation, is an intermediate species in the methanol-t o-gasoline conversion. Syngas can be directly converted to DME using t he Liquid Phase Dimethyl Ether Synthesis (LP-DME) process developed at the University of Akron in conjunction with Electric Power Research I nstitute. This direct one-step conversion of syngas-to-DME can then be an ideal front end for further conversion to gasoline. This substitut ion (syngas-to-methanol by syngas-to-DME) is justified because DME res ults in an identical hydrocarbon distribution over the ZSM-5 catalyst as methanol. The DME-to-Gasoline (DTG) process thus involves the conve rsion steps of syngas-to-DME and DME-to gasoline. The UA/EPRI DTG proc ess offers advantages over the Mobil MTG process in several areas. The se include heat duty and heat of reaction, adiabatic temperature rise, hydrocarbon product yield and selectivity, syngas conversion, and ove rall process efficiency. The conceptual benefits of the DTG process ha ve been demonstrated experimentally in a fluidized bed reactor system operative at the University of Akron. The salient features of the DTG process and process comparison to the Mobil MTG process are discussed in this paper.