The process produces a diesel stream from a biorenewable feedstock by hydrotreating to remove heteroatoms and saturate olefins. The recycle gas is recycled to the hydrotreating reactor without removing hydrogen sulfide, which is needed in the biorenewable feed to keep the hydrotreating catalyst active. A purification unit can be utilized on a purge gas stream to purify the gas and improve hydrogen concentration in the recycle gas when added to the recycle gas.