A process and a
plant for the production of
hydrogen or for the synthesis of
ammonia, said process comprising the following steps: (a) performing a reforming process (101) of a
hydrocarbon feedstock (1) to generate a raw
syngas (2), said reforming process comprising at least an autothermal reforming step (104) in presence of
oxygen-enriched air or
pure oxygen (3) produced by an
air separation unit (ASU; 103); (b) subjecting said raw
syngas (2) to a post-treatment (102) providing
hydrogen (H2; 4), a CO2-enriched
stream (5), and a residual gas (6); said post-treatment comprising at least a
water gas shift conversion step (105) of said raw
syngas into a shifted syngas (7), a pressure swing absorption step (106), and a cryogenic separation step (107); wherein said pressure swing absorption step produces said
hydrogen and a first
tail gas (8) comprising
carbon monoxide (CO),
carbon dioxide (CO2), residual hydrogen (H2) and unreacted
hydrocarbon feedstock from the shifted syngas (7), and said cryogenic separation step separates the CO2-enriched
stream and a second
tail gas (9) from said first
tail gas; said post-treatment (102) comprising a further separation step (120) of a CO2-containing
stream (11) and of the residual gas (6) from said second tail gas; (c) recycling said residual gas (6) as feed to said reforming process and / or as fuel to one or more fired heater(s) (10) of said process; (d) optionally feeding a portion (4.8) of said hydrogen (4) obtained in step (b) as fuel to one or more fired heater(s) of said process; (e) optionally an
ammonia synthesis step (110) wherein said hydrogen (4) and a
nitrogen (N2)-containing stream (12) produced by said ASU (103) are reacted in a given stoichiometric ratio and in
ammonia (NH3) synthesis conditions to obtain an ammonia-containing product (13).