Hydrocracking processes having an enhanced efficiency of hydrogen utilization

• US 4,362,613 A
• Filed: 03/13/1981
• Issued: 12/07/1982
• Est. Priority Date: 03/13/1981
• Status: Expired due to Term

• Current Assignee: Permea Incorporated (Linde Plc)
• Original Assignee: Monsanto Company (Bayer AG)
• Inventors: MacLean, Donald L.
• Primary Examiner(s): Gantz, Delbert E.
• Assistant Examiner(s): Schmitkons, G. E.
• Application Number:
  US06/243,273
• Time in Patent Office: 634 Days
• Field of Search: 208/108, 55/16
• US Class Current: 208/108
• CPC Class Codes: C10G 49/22 Separation of effluents

Abstract

A hydrocrackate from a hydrocracking zone operating under hydrocracking conditions is separated into at least one liquid phase and a separated vapor phase wherein the separated vapor phase has a greater concentration of hydrogen than the minimum concentration of hydrogen in the vapor phase in the hydrocracking zone. At least a portion of the separated vapor phase is contacted with the feed side of a polymeric membrane 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 having a concentration of hydrogen greater than the concentration of hydrogen in the separated vapor phase and greater than the concentration of hydrogen in the hydrogen feed gas. The hydrogen permeate is compressed and recycled to the hydrocracking zone.

Claims

1. A process for catalytically hydrocracking a hydrocarbonaceous feed comprising:

(a) cracking in a hydrocracking zone the hydrocarbonaceous feed in the presence of hydrogen and a hydrocracking catalyst under hydrocracking conditions comprising a temperature of at least about 250°

C. and a pressure of at least about 45 atmospheres absolute wherein said hydrocracking zone has a hydrocracking vapor phase and a hydrocracking liquid phase wherein said hydrogen is provided by a hydrogen feed gas to produce a hydrocrackate, and wherein the hydrogen feed gas is provided in an amount sufficient to maintain a concentration of hydrogen in the hydrocracking vapor phase of at least about 65 volume percent;

(b) separating the hydrocrackate into at least one liquid phase and a separated vapor phase, said separated vapor phase being at a temperature less than about 70°

C. and a pressure of at least about 0.5 times the pressure in the hydrocracking zone, the separated vapor phase has a concentration of hydrogen of at least 65 volume percent;

(c) bringing at least a portion of said separated vapor phase into contact with a feed side of a polymeric membrane selective to the permeation of hydrogen as compared to methane;

(d) maintaining the opposite side of the polymeric membrane at a pressure of at least about 20 atmospheres below the pressure at the feed side of the polymeric membrane to permeate hydrogen to the opposite side of the polymeric membrane and provide a hydrogen permeate having a concentration of hydrogen of at least about 90 volume percent;

(e) withdrawing non-permeate from the feed side of the polymeric membrane;

(f) removing the hydrogen permeate from said opposite side of the polymeric membrane;

(g) compressing the removed hydrogen permeate to a sufficient pressure for passage to the hydrocracking zone; and

(h) then recycling the hydrogen permeate to the hydrocracking zone as a portion of the hydrogen feed gas.