Methanol is a typical alcohol product made from syngas. Methanol is the simplest of all alcohols, and is used in the synthesis of other alcohols, as well as for making a wide range of other industrial chemicals.
Methanol is manufactured using syngas with a H2/CO ratio of 2:1, via the following overall reaction:
CO + 2H2 → CH3OH
Methanol production uses gas-phase synthesis technology. The synthesis loop pressure, reactor type used, and method of waste-heat recovery broadly differentiate gas-phase methanol-synthesis schemes. The modern large-capacity methanol processes use low-pressure synthesis loops with copper-based catalysts. Quench-type, multibed intercooled, or isothermal reactors are used to minimize reactor size and maximize recovery of process waste heat. Crude methanol, received from a gas-phase synthesis reactor will have excessive water. Lighter components are typically separated in a topping column, and the water and other heavies are removed in a distillation column. A two or three column distillation scheme is typically used. The two-column distillation scheme offers low capital expenditures, and the three-column distillation scheme offers low-energy-consumption features. The scheme that integrates better with the syngas preparation and synthesis section is normally selected.