Method of gas stream purification having independent vapor and liquid refrigeration using a single refrigerant

A method for recovering liquifiable hydrocarbons from a gas stream by the chilling of said gas stream and a liquid stream and the absorption of said liquifiable hydrocarbons by the chilled liquid stream, said method comprising:

• a) indirectly heat exchanging said liquid stream with a liquid phase absorber effluent to cool said liquid stream;
• b) dividing the cooled liquid stream into a liquid chiller feed and a by-pass stream comprising 1 to 25 wt % of the cooled liquid stream;
• c) passing said liquid chiller feed to a chiller having a single shell and indirectly contacting said chiller feed with a refrigerant in said chiller and chilling said chiller feed to produce an absorber liquid;
• d) indirectly heat exchanging said gas stream with an absorber gas to cool said gas stream;
• e) combining the cooled gas stream with said by-passed stream to produce a gaseous chiller feed;
• f) passing said gaseous chiller feed to said chiller separately from said liquid chiller feed and indirectly contacting said gas stream with said refrigerant in said chiller to chill said gaseous chiller feed and produce a chilled gaseous stream;
• g) adjusting the temperature of said chilled gaseous stream by varying the amount of said liquid stream that is divided into said by-pass stream;
• h) contacting said chilled gaseous stream and said absorber liquid in an absorber and recovering said absorber gas, said absorber gas having a reduced quantity of liquifiable hydrocarbons relative to said gas stream, and the liquid phase absorber effluent;
• and
• i) recovering said refrigerant from said chiller, and compressing, condensing, and indirectly heat exchanging said refrigerant with said liquid phase absorber effluent.

A process for producing a hydrogen-rich gas stream by treating a hydrogen and hydrocarbon-containing effluent from a catalytic hydrocarbon conversion reaction zone comprising the steps of:

• a) passing a hydrogen and hydrocarbon-containing effluent to a separation zone and recovering therefrom a hydrogen-containing vapor phase and a first liquid phase comprising hydrocarbons;
• b) passing at least a portion of the hydrogen-containing vapor phase in indirect heat exchange with a hydrogen-rich gas stream;
• c) indirectly heat exchanging at least a portion of said first liquid phase in indirect heat exchange with a second liquid phase;
• d) dividing at least a portion of said first liquid phase into a chiller feed and a by-pass stream;
• e) refrigerating the chiller feed by indirect contact with a refrigerant in a chiller to produce a refrigerated first liquid;
• f) admixing the heat exchanged hydrogen-containing vapor phase and the bypass stream, refrigerating the admixed heat exchanged hydrogen-containing vapor phase and by-pass stream separate from said first liquid phase by indirect contact with said refrigerant in said chiller and controlling the temperature of the refrigerated hydrogen-containing vapor phase by adjusting the amount of said by-pass stream that is divided from said first liquid stream;
• g) passing the refrigerated hydrogen-containing vapor phase and the refrigerated first liquid to an absorption zone and countercurrently contacting said refrigerated hydrogen-containing vapor phase with said refrigerated first liquid in said absorption zone to absorb hydrocarbons from said hydrogen-rich gas stream;
• h) withdrawing said second liquid phase from said absorption zone;
• and,
• i) withdrawing said hydrogen-rich gas stream from said absorption zone and recovering said hydrogen-rich gas stream after the heat exchange of step (b).