Patent ID: 8557218

Claim:
A method for recovery of hydrogen and CO 2 in a refinery, comprising: dividing an input stream containing hydrogen, carbon dioxide, and a hydrocarbon into a first input portion and a second input portion, the input stream comprising an effluent from a reforming unit, the input stream exhibiting a hydrogen content of at least about 70 vol % and a CO 2 content of at least about 5 vol %, the first input portion comprising from about 5 vol % to about 60 vol % of the input stream; combining the first input portion and a first tail gas stream, the combined first input portion and first tail gas stream exhibiting a CO 2 content of less than about 70 vol %; separating the first input portion and a first tail gas stream to form a CO 2 recovery stream and a hydrogen enriched stream, the CO 2 recovery stream having a CO 2 content of at least about 70 vol %, the CO 2 recovery stream containing at least about 80% of the CO 2 in the combined first input portion and first tail gas stream; exposing the hydrogen enriched stream and the second input portion to an adsorbent in a cycling adsorber unit at a pressure of at least about 500 psig (about 3.4 MPag) to produce a hydrogen product stream having a hydrogen content of at least about 90 vol %, the hydrogen product stream containing at least about 85% of the hydrogen in the input stream; contacting the adsorbent with a first regeneration stream at a first pressure of about 45 psig (about 310 kPag) to about 130 psig (about 900 kPag) to form the first tail gas stream, the first tail gas stream containing a first combined content of CO plus CO 2 of at least about 60 vol % on a dry basis and a first hydrocarbon content of about 10 vol % or less on a dry basis; contacting the adsorbent with a second regeneration stream at a second pressure of about 5 psig (about 35 kPag) to about 20 psig (about 140 kPag) to form a second tail gas stream, the second tail gas stream containing a second combined content of CO plus CO 2 of about 10 vol % or less on a dry basis and a second hydrocarbon content of at least about 40 vol % on a dry basis, the second tail gas stream comprising from about 25% to about 60% of a combined volume of the first and second tail gas streams; and introducing the second tail gas stream as an input to the reforming unit.