Processes for recovering LPG from a reforming-zone effluent

A process for recovering C3/C4 hydrocarbons from a reformate effluent stream, the process comprising:

• separating, in a first separation zone, a reforming-zone effluent comprising H2, C4− hydrocarbons, and C5+ hydrocarbons, including aromatics, to form a net gas phase stream comprising C6− hydrocarbons and H2 and a liquid phase hydrocarbon stream comprising C5+ hydrocarbons including aromatics;
• separating, in a second separation zone, the net gas phase stream to form a first H2 rich-stream and a gas stream that comprises H2, and C4+ hydrocarbons;
• cooling the gas stream to form a cooled gas stream;
• cooling all of the liquid phase hydrocarbon stream to form a cooled liquid phase hydrocarbon stream;
• absorbing C3/C4 hydrocarbons from the cooled gas stream with the cooled liquid phase hydrocarbon stream in an absorbing zone to form a fuel gas stream and a C3/C4 enriched liquid phase hydrocarbon stream;
• separating the C3/C4 enriched liquid phase hydrocarbon stream, in a third separation zone, into a liquid LPG product stream, and an overhead receiver vapor stream;
• splitting the overhead receiver vapor stream into a first portion and a second portion;
• and
• combining only the first portion of the overhead receiver vapor stream with the gas stream.

A process for recovering C3/C4 hydrocarbons from a reformate effluent stream, the process comprising:

• separating, in a first separation zone, a reforming-zone effluent comprising H2, C4− hydrocarbons, and C5+ hydrocarbons, including aromatics, to form a net gas phase stream comprising C6− hydrocarbons and H2 and a liquid phase hydrocarbon stream comprising C5+ hydrocarbons including aromatics;
• separating, in a second separation zone, the net gas phase stream to form a first H2 rich-stream and a gas stream that comprises H2, and C4− hydrocarbons;
• separating hydrogen, in a membrane separation zone, from the gas stream to form a second H2 rich-stream and a H2 depleted gas stream;
• absorbing C3/C4 hydrocarbons from the H2 depleted gas stream with the liquid phase hydrocarbon stream in an absorbing zone to form a fuel gas stream and a C3/C4 enriched liquid phase hydrocarbon stream;
• separating the C3/C4 enriched liquid phase hydrocarbon stream, in a third separation zone, into a liquid LPG product stream, and an overhead receiver vapor stream;
• splitting the overhead receiver vapor stream into a first portion and a second portion;
• and
• combining only the first portion of the overhead receiver vapor stream with the H2 depleted gas stream.