Process for synthesising methanol

Abstract

A process for synthesising methanol is described comprising the steps of (i) reforming a hydrocarbon feedstock in a hydrocarbon reforming unit comprising a fired heater and an autothermal reformer in series to form a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide; (ii) dividing the synthesis gas into a first portion and a second portion, (iii) converting the first portion of synthesis gas into a methanol product in a methanol synthesis unit comprising one or more methanol synthesis reactors; and (iv) recovering a purge gas stream from the methanol synthesis unit, wherein the second portion of synthesis gas is passed to a hydrogen production unit where it is subjected to one or more stages of water gas shift in a water-gas shift unit to form a hydrogen-enriched gas, the a hydrogen-enriched gas is subjected to a step of carbon dioxide removal in a carbon dioxide removal unit to form a hydrogen product stream and a carbon dioxide stream, the carbon dioxide stream is recovered and at least a portion of the hydrogen product stream is fed to the fired heater as a fuel. A method of retrofitting a methanol production unit to perform the process is also provided.

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