Methanol Production from Natural Gas (Steam Reforming)

The process under analysis comprises three major sections: (1) syngas generation; (2) methanol synthesis; and (3) purification.

Syngas generation. Natural gas feedstock is treated in a fixed-bed-type reactor that converts higher hydrocarbons contained in the feed gas into a gas rich in methane and hydrogen, in order to protect the catalyst. Then, the treated gas is converted to syngas in a steam reformer. There, methane reacts catalytically with steam, generating CO and H2. The reformer outlet stream is then cooled and the condensed water is separated from the syngas.

Methanol synthesis. The syngas is compressed and mixed with recycle gas and fed to the methanol-synthesis reaction system, where CO and CO2 react with hydrogen to generate methanol. The reactor outlet gas is mainly comprised of methanol, water vapor, unconverted hydrogen, CO and CO2. This stream is cooled, and methanol and water are separated from the gases by condensation. The separated gas is used as fuel with a small purge. The water-methanol condensate stream is sent to the purification steps.

Purification. The purification area is composed of two distillation columns. The topping column removes the dissolved gases from the crude methanol stream. In the refining column, part of the methanol produced is obtained from the top of the column while water obtained as column bottoms is recycled as process water.