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Effluent gas streams for steam reforming, partial oxidation or coal gasification operations are advantageously treated in shift conversion, scrubbing and pressure swing adsorption units for recovery of a purified, hydrogen-containing product gas stream. By recycling a portion of the waste gas remove

Effluent gas streams for steam reforming, partial oxidation or coal gasification operations are advantageously treated in shift conversion, scrubbing and pressure swing adsorption units for recovery of a purified, hydrogen-containing product gas stream. By recycling a portion of the waste gas removed from the pressure swing adsorption system to the shift conversion unit and/or to the effluent gas generation operation, enhanced product recovery is achieved without the necessity for employing low temperature shift or for achieving essentially complete removal of the carbon dioxide content of the gas being treated prior to its passage to said pressure swing adsorption system.

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1. An improved process for the production of a hydrogen-containing product gas consisting essentially of: (a) generating an effluent gas stream comprising hydrogen, carbon dioxide, carbon monoxide and water vapor; (b) upon cooling said effluent stream to about 350° C. -400° C., subjecting said e

1. An improved process for the production of a hydrogen-containing product gas consisting essentially of: (a) generating an effluent gas stream comprising hydrogen, carbon dioxide, carbon monoxide and water vapor; (b) upon cooling said effluent stream to about 350° C. -400° C., subjecting said effluent stream to at least a high temperature catalytic water gas shift conversion, thereby converting most of the carbon monoxide in said effluent stream to additional hydrogen and carbon dioxide; (c) scrubbing at least a major portion of the carbon dioxide from said thus-treated effluent stream to produce a carbon dioxide-depleted effluent stream but without essentially complete removal of carbon dioxide therefrom; (d) passing the thus carbon dioxide-depleted effluent stream to a pressure swing adsorption system capable of discharging a purified, hydrogen-containing product gas therefrom as a less readily adsorbable component of said effluent stream, the more readily adsorbable component thereof comprising residual carbon dioxide and other impurities present in said effluent stream, said more readily adsorbable component being removed from the pressure swing adsorption system during the countercurrent depressurization and/or purge steps of the processing cycle in each adsorbent bed of said system, said cycle comprising higher pressure adsorption with discharge of said less readily adsorbable component from the product end of the bed, cocurrent depressurization with release of void space gas from the product end of the bed, countercurrent depressurization of the bed to lower desorption pressure and/or purge with release of impurities-containing waste gas from the feed end of the bed, and repressurization to higher adsorption pressure; (e) compressing said waste gas removed from the pressure swing adsorption system during said countercurrent depressurization and/or purge steps; (f) recycling at least about 40% of said compressed waste gas to said shift conversion and/or effluent gas generation steps for additional hydrogen production, whereby said effluent gas stream is advantageously converted to the desired hydrogen-containing product stream and carbon dioxide waste gas at high hydrogen product recovery levels. 2. The process of claim 1 in which said effluent gas stream is generated by the primary steam reforming of hydrocarbons without the secondary reforming thereof. 3. The process of claim 2 and including subjecting said primary reforming effluent to secondary reforming. 4. The process of claim 1 in which said effluent gas stream is generated by the partial oxidation of hydrocarbons. 5. The process of claim 1 in which said effluent gas stream is generated by coal gasification. 6. The process of claim 2 in which the reformer effluent gas stream contains at least about 3 vol. % methane, at least about 20% of the recycled waste gas from the pressure swing adsorption system being recycled to said reformer employed for said primary steam reforming. 7. The process of claim 3 in which the secondary reformer effluent gas contains less than about 1 vol. % methane, at least about 20% of the waste gas recycled from the pressure swing adsorption system being recycled to the shift conversion step. 8. The process of claim 1 and including cooling said effluent gas stream to on the order of about 350° C. prior to said conversion step. 9. The process of claim 1 in which said effluent gas stream also contains methane. 10. The process of claim 9 in which at least a portion of the methane-containing waste gas from the pressure swing adsorption system is recycled at an elevated pressure to said effluent gas stream generation step. 11. The process of claim 9 in which a portion of the methane-containing waste gas from the pressure swing adsorption system is diverted at an elevated adsorption pressure to a supplemental pressure swing adsorption system, the less readily adsorbable product gas discharged therefrom comprising additional purified, hydrogen-containing product, and the more readily adsorbable waste gas removed therefrom comprising a methane-containing gas stream suitable for use as a fuel gas. 12. The process of claim 9 in which a portion of the methane-containing waste gas from the pressure swing adsorption system is diverted from the process, said diverted waste gas being suitable for use as a fuel gas. 13. The process of claim 10 in which a portion of said waste gas from the pressure swing adsorption process is recycled to said effluent gas generation step and a portion of said waste gas is diverted from the process. 14. The process of claim 11 in which a portion of said waste gas from the pressure swing adsorption process is diverted to said supplemental pressure swing adsorption system and a portion of said waste gas is diverted from the overall process. 15. The process of claim 1 in which said effluent gas stream also contains nitrogen and/or argon. 16. The process of claim 15 in which the higher pressure adsorption step in said pressure swing adsorption system is carried out so as to allow a breakthrough of said nitrogen and/or argon into the purified, hydrogen-containing product gas discharged from the product end of the adsorbent bed. 17. The process of claim 15 in which at least a portion of the nitrogen and/or argon containing waste gas from the pressure swing adsorption system is diverted from the process. 18. The process of claim 15 in which the recycled waste gas from the pressure swing adsorption system comprises only the gas richest in hydrogen released during the initial, higher pressure portion of the countercurrent depressurization step, the gas released during further countercurrent depressurization to lower desorption pressure, together with any additional gas released at said lower desorption pressure, being diverted from the overall process. 19. The process of claim 15 in which the recycled waste gas from the pressure swing adsorption system comprises the gas richest in hydrogen released during the initial, higher pressure portion of the countercurrent depressurization step, together with gas released during the last part of the purge step, said nitrogen and/or argon being removed from the bed principally during the last portion of said countercurrent depressurization step and during the initial portion of said increasing pressure purge step. 20. The process of claim 13 in which said effluent gas stream is generated by the primary steam reforming of hydrocarbons without the secondary reforming thereof, the reformer effluent gas stream containing at least about 3 vol. % methane, at least about 20% of the waste gas from the pressure swing adsorption system being recycled to the primary reformer. 21. The process of claim 20 in which said effluent gas stream also contains nitrogen and/or argon and in which the higher pressure adsorption step in said pressure swing adsorption system is carried out so as to allow a breakthrough of said nitrogen and/or argon into the purified, hydrogen-containing product gas discharged from the product end of the adsorbent bed. 22. The process of claim 20 in which said effluent gas also contains nitrogen and/or argon and in which the recycled waste gas from the pressure swing adsorption system comprises only the gas richest in hydrogen and relatively free of nitrogen and argon released during the initial, higher pressure portion of the countercurrent depressurization step. 23. The process of claim 20 in which said effluent gas system also contains nitrogen and/or argon and in which the recycled waste gas from the pressure swing adsorption system comprises the gas richest in hydrogen released during the initial, higher pressure portion of the countercurrent depressurization step, together with gas released during the last portion of the purge step, such recycled waste gas being relatively free of nitrogen and/or argon. 24. The process of claim 13 in which said effluent gas stream is generated by the secondary reforming of a primary reformer effluent or by partial oxidation of hydrocarbons, said effluent gas stream containing less than about 1 vol. % methane, at least about 20% of the waste gas from the pressure swing adsorption system being recycled to the shift conversion step. 25. The process of claim 24 in which said effluent gas stream also contains nitrogen and/or argon and in which the higher pressure adsorption step in said pressure swing adsorption system is carried out so as to allow a breakthrough of said nitrogen and/or argon into the purified, hydrogen-containing product gas discharged from the product end of the adsorbent bed. 26. The process of claim 24 in which said effluent gas stream also contains nitrogen and/or argon and in which the recycled waste gas from the pressure swing adsorption system comprises only the gas richest in hydrogen and relatively free of nitrogen and argon released during the initial, higher pressure portion of the countercurrent depressurization step. 27. The process of claim 24 in which said effluent gas stream also contains nitrogen and/or argon and in which the recycled waste gas from the pressure swing adsorption system comprises the gas richest in hydrogen released during the initial, higher pressure portion of the countercurrent depressurization step, together with gas released during the last portion of the purge step, such recycled gas being relatively free of nitrogen and/or argon. 28. The process of claim 20 in which said effluent gas stream also contains nitrogen and/or argon and in which at least a portion of the waste gas from the pressure swing adsorption process is diverted from the process. 29. The process of claim 24 in which said effluent gas stream also contains nitrogen and/or argon and in which at least a portion of the waste gas from the pressure swing adsorption process is diverted from the process. 30. The process of claim 1 in which said hydrogen-containing product gas comprises an ammonia synthesis gas mixture of hydrogen and nitrogen. 31. An improved apparatus for the production of a hydrogen-containing product gas consisting essentially of: (a) means for generating an effluent gas stream comprising hydrogen, carbon monoxide and carbon dioxide; (b) cooling and high temperature catalytic water gas shift conversion means for converting carbon monoxide in said effluent gas stream to hydrogen and carbon dioxide; (c) scrubbing means capable of removing at least a major portion of the carbon dioxide from the thus-water gas shifted effluent gas stream, but without essentially complete removal of carbon dioxide therefrom; (d) a pressure swing adsorption system capable of discharging a purified, hydrogen-containing gas stream and waste gas comprising residual carbon dioxide and other impurities present in said effluent gas stream; (e) compression means for compressing said waste gas; and (f) conduit means for recycling at least about 40% of said compressed waste gas to said shift conversion means and/or to said means for generating an effluent gas stream, whereby said effluent gas stream may advantageously be converted to the desired hydrogen-containing product stream and a carbon dioxide waste gas at high hydrogen product recovery levels. 32. The apparatus of claim 31 and which said means for generating an effluent gas stream comprises a primary steam reformer. 33. The apparatus of claim 32 and including a secondary reformer. 34. The apparatus of claim 31 in which said means for generating an effluent gas stream comprises a partial oxidation unit. 35. The apparatus of claim 31 in which said means for generating an effluent gas stream comprises a coal gasification unit. 36. The apparatus of claim 31 and including a supplemental pressure swing adsorption system and conduit means for diverting at least a portion of the waste gas from said pressure swing adsorption system to said supplemental pressure swing adsorption system. 37. The apparatus of claim 31 and including conduit means for discharging a portion of the waste gas from the pressure swing adsorption system. 38. The apparatus of claim 36 and including recovering the less readily adsorbed product gas as additional purified, hydrogen-containing product. 39. The apparatus of claim 31 in which said conduit means is adapted to recycle compressed waste gas to said shift conversion means. 40. The apparatus of claim 31 in which said conduit means is adapted to recycle compressed waste gas to said means for generating an effluent gas stream. 41. The apparatus of claim 31 and including means for discharging waste gas released during the later portion of the countercurrent depressurization step and the lower desorption pressure in said pressure swing adsorption system, said means for recycling waste gas being adapted for the recycle of only the gas richest in hydrogen released during the initial, higher pressure portion of the countercurrent depressurization step in said pressure swing adsorption system. 42. The apparatus of claim 41 and including means for recycling the gas released during the last part of a purge step carried out in said pressure swing adsorption system.