Process for synthesising methanol

A process for synthesising methanol with low carbon dioxide emissions comprising: reforming a hydrocarbon feedstock, preferably natural gas, in a reforming section comprising a first autothermal reformer to form a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide; converting the synthesis gas into a methanol product in a methanol loop (comprising one or more methanol synthesis reactors); and recovering a purge gas stream from the methanol loop; wherein at least some of the purge gas stream is used to generate a purge gas feedstock stream by treatment of the purge gas stream in a purge gas treatment unit by steps of reforming, water-gas shift and carbon dioxide removal to form a hydrogen stream, which is used as fuel for example to heat process streams within the reforming operations, methanol loop and/or purge gas treatment unit. The process does not comprise a steam methane reformer upstream of the first autothermal reformer and the removed carbon dioxide stream is recovered. The disclosure also relates to a method of retrofitting a methanol production unit by installing a purge gas treatment unit as described.