Methanol is an important primary chemical product, used as a chemical feedstock for production of a range of important industrial chemicals, primarily acetic acid, formaldehyde, methyl methacrylate and methyl tertiary-butyl ether (MTBE).
Methanol is also used directly as a fuel or fuel supplement. As fuel, methanol can be used to fire rapid-start utility peak-shaving combustion turbines; to substitute for or blend with gasoline to power vehicles; to be converted to gasoline via the ExxonMobil methanol-to-gasoline (MTG) process; or to be converted to dimethyl ether (DME) to power diesel engines.
Most methanol is made from syngas. Although the majority of methanol synthesis is based on natural gas as feedstock, coal-derived syngas is also used; coal/solid feedstocks are used to make 9% of the worldwide output of methanol mostly in China.
Catalytic conversion of hydrogen (H2) and carbon monoxide (CO) from coal-derived syngas into methanol can be done with conventional gas-phase processes, or with a liquid phase methanol (LPMEOH™) process developed by Air Products and Chemicals. The reactions of interest are:
2 H2 + CO → CH3OH
CO2 + 3 H2 → CH3OH + H2O
CO + H2O → CO2 + H2
All three reactions are highly exothermic. Catalyst systems used for methanol synthesis are typically mixtures of copper, zinc oxide, alumina and magnesia. Recent advances have also yielded a possible new catalyst composed of carbon, nitrogen, and platinum.
Methanol production from syngas is a commercially demonstrated technology, using both natural gas and coal as feedstock. The current world-class methanol plants are typically in the order of 2,000 to 2,500 metric tons per day (t/d). Larger-scale (5,000 t/d) single train methanol process technologies are being offered.
(The National Energy Technology Laboratory (NETL)
