Patent ID: 8829253

Claim:
A process for forming ethanol, comprising the steps of: (a) carbonylating methanol in the presence of a carbonylation catalyst in a carbonylation reactor to form acetic acid; (b) hydrogenating the acetic acid in the presence of a hydrogenation catalyst in a hydrogenation reactor to form a crude ethanol stream; (c) separating the crude ethanol stream into a vapor stream comprising hydrogen and carbon monoxide and an ethanol product stream; (d) reacting residual carbon monoxide from at least a portion of the vapor stream in a methanation unit in the presence of a methanation catalyst to form a methanated stream comprising hydrogen, methane, and less than 2 vol. % carbon monoxide; wherein the methanation catalyst is different than the hydrogenation catalyst (e) directing the methanated stream to the hydrogenation reactor.