Hydrocracking processes having an enhanced efficiency of hydrogen utilization

摘要

A hydrocrackate (14) from a hydrocracking zone (10) operating under hydrocracking conditions is separated into vapor phase has a greater concentration of hydrogen than the minimum concentration of hydrogen in the vapor phase in the hydrocraking zone. at least a portion of the separated vapor phase (22) is contacted with the feed side of a polymeric membrane in a permeator (28), the membrane being selective to the permeation of hydrogen as compared to the permeation of methane, and the opposite side of the polymeric membrane is maintained at a pressure sufficiently below the pressure at the feed side of the polymeric membrane to permeate hydrogen to the opposite side of the polymeric membrane and to provide a hydrogen permeate (30) having a concentration of hydrogen greater than the concentration of hydrogen in the separated vapor phase (22) and greater than the concentration of hydrogen feed gas (44, 46). The hydrogen permeate (30) is compressed and recycled to the hydrocracking zone (10).