Process for separating hydrogen from an olefin hydrocarbon effluent vapor stream

A process for providing refrigeration to streams within an integrated main heat exchanger comprising:

• a. providing a pressurized and totally condensed liquid refrigerant stream, wherein the pressurized and totally condensed liquid refrigerant stream comprises a pressure between 1,000 kPa·G and 1,750 kPa·G;
• b. sub-cooling the pressurized and totally condensed liquid refrigerant stream in the integrated main heat exchanger to provide sub-cooled liquid stream, wherein the sub-cooled liquid stream comprises a pressure between 15 kPa·G and 50 kPa·G and a temperature between 10° C. and −25° C.;
• c. lowering the pressure of the sub-cooled liquid stream in a first control valve to provide a first pressure-reduced, temperature-decreased vapor/liquid mixed stream, wherein the first pressure-reduced, temperature-decreased vapor/liquid mixed stream comprises a temperature between −30° C. and −45° C.;
• d. introducing the first pressure-reduced, temperature-decreased vapor/liquid mixed stream into a first thermosiphon vessel to provide a first cold liquid refrigerant stream and a first flashed vapor stream;
• e. circulating the first cold liquid refrigerant stream from a bottom outlet of the first thermosiphon vessel, through the integrated main heat exchanger, and then back to an upper inlet of the first thermosiphon vessel to maintain a steady internal liquid level within the first thermosiphon vessel, wherein the integrated main heat exchanger vaporizes the first cold liquid refrigerant stream to provide a first two-phase refrigerant stream, wherein the first two-phase refrigerant stream comprises between 30% and 50% vapor;
• f. compressing the first flashed vapor stream in at least one first compressor to provide a first compressed stream;
• g. cooling the first compressed stream in a final stage discharge condenser to provide the pressurized and totally condensed liquid refrigerant stream;
• h. providing a pressurized and cooled refrigerant stream, wherein the pressurized and cooled refrigerant stream comprises a pressure between 1,650 kPa·G and 1,950 kPa·G;
• i. cooling the pressurized and cooled refrigerant stream in the integrated main heat exchanger to provide a cooled and totally condensed liquid stream, wherein the cooled and totally condensed liquid stream comprises a temperature between −30° C. and −40° C.;
• j. lowering the pressure and temperature of the cooled and totally condensed liquid stream in a second control valve to provide a second pressure-reduced temperature-decreased vapor/liquid mixed stream, wherein the second pressure-reduced temperature-decreased vapor/liquid mixed stream comprises a pressure between 450 kPa·G and 700 kPa·G and a temperature between −50° C. and −70° C.;
• k. introducing the second pressure-reduced temperature-decreased vapor/liquid mixed stream into a second thermosiphon vessel to provide a first warm liquid refrigerant stream and a second flashed vapor stream;
• l. circulating the first warm liquid refrigerant stream from a bottom outlet of the second thermosiphon vessel, through the integrated main heat exchanger, and then back to an upper inlet of the second thermosiphon vessel to maintain a steady internal liquid level within the second thermosiphon vessel, wherein the integrated main heat exchanger vaporizes the first warm liquid refrigerant stream to provide a second two-phase refrigerant stream, wherein the second two-phase refrigerant stream comprises between 30% and 50% vapor;
• m. drawing a second warm liquid refrigerant stream from the first warm liquid refrigerant stream and lowering the pressure of the second warm liquid refrigerant stream in a third control valve to provide a pressure-reduced temperature-decreased liquid stream, wherein the pressure-reduced temperature-decreased liquid stream comprises a pressure between 5 kPa·G and 50 kPa·G and a temperature between −95° C. and −115° C.;
• n. introducing the pressure-reduced temperature-decreased liquid stream to a third thermosiphon vessel to provide a second cold liquid refrigerant stream and a third flashed vapor stream;
• o. circulating the second cold liquid refrigerant stream from a bottom outlet of the third thermosiphon vessel, through the integrated main heat exchanger, and then back to an upper inlet of the third thermosiphon vessel to maintain a steady internal liquid level within the third thermosiphon vessel, wherein the integrated main heat exchanger vaporizes the second cold liquid refrigerant stream to provide a third two-phase refrigerant stream, wherein the third two-phase refrigerant stream may comprise between 30% and 50% vapor;
• p. compressing the third flash vapor stream in a second compressor to provide a first stage recycle compression discharge stream;
• q. combining the second flashed vapor stream and the first stage recycle compression discharge stream to provide a combined feed stream;
• r. compressing the combined feed stream in a third compressor to provide a second compressed;
• and
• s. cooling the second compressed stream in a final stage discharger cooler to provide the first pressurized and cooled refrigerant stream.