The process and apparatus enables purification of a recycle hydrogen gas stream from hydroprocessing biorenewable feedstocks. The recycle gas stream is fed to a methanator reactor to hydrogenate carbon monoxide in the gas stream to water and methane. Other acid gases can be removed by scrubbing preferably upstream of the methanator. Removal of carbon monoxide omits the need for a hydrogen purge stream to avoid carbon monoxide accumulation and enables use of the hydrogen for a downstream hydroisomerization reaction.