Tail gas utilization for mixed alcohols production

It has been discovered that mixed-alcohol production can utilize the waste tail gas stream from the pressure-swing adsorption section of an industrial hydrogen plant. Some variations provide a process for producing mixed alcohols, comprising: obtaining a tail-gas stream from a methane-to-syngas unit (e.g., a steam methane reforming reactor); compressing the tail-gas stream; separating the tail-gas stream into at least a syngas stream, a CO2-rich stream, and a CH4-rich stream; introducing the syngas stream into a mixed-alcohol reactor operated at effective alcohol synthesis conditions in the presence of an alcohol-synthesis catalyst, thereby generated mixed alcohols; and purifying the mixed alcohols to generate a mixed-alcohol product. Other variations provide a process for producing clean syngas, comprising: obtaining a tail-gas stream from a methane-to-syngas unit; compressing the tail-gas stream; separating the tail-gas stream into at least a syngas stream, a CO2-rich stream, and a CH4-rich stream; and recovering a clean syngas product.