Process for Separating Hydrogen from an Olefin Hydrocarbon Effluent Vapor Stream

A process for providing refrigeration to streams within a heat exchanger comprising:

• a. cooling a first pressurized and cooled refrigerant in a heat exchanger to provide a first cooled and liquefied refrigerant stream;
• b. lowering the pressure of the first cooled and liquefied refrigerant stream in a control valve;
• c. introducing the pressure-reduced, first cooled and liquefied refrigerant stream into a first thermosiphon vessel to provide a first cold liquid refrigerant stream and a first flashed vapor stream;
• d. circulating the first cold liquid refrigerant stream from a bottom outlet of the first thermosiphon vessel, through the 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 heat exchanger vaporizes the first cold liquid refrigerant stream to provide cooling to the warm streams in the heat exchanger;
• e. compressing the first flashed vapor stream in at least one compressor to provide a compressed first refrigerant stream;
• f. cooling the compressed first refrigerant stream in a discharge condenser to provide the first pressurized and cooled refrigerant;
• g. cooling a second pressurized and cooled refrigerant in a heat exchanger to provide a second cooled and liquefied refrigerant stream;
• h. lowering the pressure of the second cooled and liquefied refrigerant stream in a second control valve;
• i. introducing the pressure-reduced second cooled and liquefied refrigerant stream into a second thermosiphon vessel to provide a warm liquid refrigerant stream and a second flashed vapor stream;
• j. circulating the warm liquid refrigerant stream from a bottom outlet of the second thermosiphon vessel, through the 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 heat exchanger vaporizes the warm liquid refrigerant stream to provide cooling to the warm streams in the heat exchanger;
• k. lowering the pressure of the warm liquid refrigerant stream in a third control valve;
• l. introducing the pressure-reduced warm liquid refrigerant stream to a third thermosiphon vessel to provide a second cold liquid refrigerant stream and a third flashed vapor stream;
• m. circulating the second cold liquid refrigerant stream from a bottom outlet of the third thermosiphon vessel, through the 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 heat exchanger vaporizes the second cold liquid refrigerant stream to provide cooling to the warm streams in the heat exchanger;
• n. compressing the third flash vapor stream in a first compressor to provide a compressed third refrigerant stream;
• o. combining the second flashed vapor stream and the compressed third refrigerant stream to provide a combined stream;
• p. compressing the combined stream in a subsequent compressor to provide a compressed combined refrigerant stream;
• and
• q. cooling the compressed combined refrigerant stream in a discharger cooler to provide the first pressurized and cooled refrigerant.