System for incondensable component separation in a liquefied natural gas facility

A process for liquefying a natural gas stream, said process comprising:

• (a) cooling said natural gas stream in a first refrigeration cycle via indirect heat exchange with a first refrigerant to thereby provide a cooled natural gas stream;
• (b) separating at least a portion of said cooled natural gas stream into a predominantly methane overhead stream and a heavies-rich bottoms stream in a heavies removal column;
• (c) flashing at least a portion of said predominantly methane overhead stream to thereby provide a predominantly vapor stream and a predominantly liquid stream;
• (d) compressing at least a portion of said predominantly vapor stream to thereby provide a compressed vapor stream;
• (e) cooling at least a portion of said compressed vapor stream via indirect heat exchange with a second refrigerant in a second refrigeration cycle to thereby provide a cooled compressed stream;
• (f) separating at least a portion of said cooled compressed stream in a separation vessel to thereby provide a predominantly vapor overhead stream and a predominantly liquid bottoms stream;
• and
• (g) introducing a first portion of said predominantly liquid bottoms stream into said heavies removal column as a reflux stream.

A facility for liquefying a natural gas stream, said facility comprising:

• a first closed-loop refrigeration cycle comprising a first warm natural gas inlet and a first cool natural gas outlet, wherein said first closed-loop refrigeration cycle is operable to cool at least a portion of said natural gas stream via indirect heat exchange with a first refrigerant to thereby provide a cooled natural gas stream withdrawn via said first cool natural gas outlet;
• a heavies removal column defining a first fluid inlet, a first vapor outlet, a first liquid outlet, and a first reflux inlet, wherein said first fluid inlet of said heavies removal column is in fluid flow communication with said first cool natural gas outlet of said first refrigeration cycle, wherein said heavies removal column is operable to separate at least a portion of said cooled natural gas stream into a predominantly liquid stream withdrawn via said first liquid outlet and a predominantly vapor stream withdrawn via said first vapor outlet;
• a second closed-loop refrigeration cycle comprising a second warm natural gas inlet and a second cool natural gas outlet, wherein said second warm natural gas inlet is in fluid flow communication with said first vapor outlet, wherein said second closed-loop refrigeration cycle is operable to cool at least a portion of said predominantly vapor stream withdrawn from said first vapor outlet of said heavies removal column via indirect heat exchange with a second refrigerant to thereby provide a further cooled natural gas stream;
• an expander defining a high pressure inlet and a low pressure outlet, wherein said high pressure inlet is in fluid flow communication with said second cool natural gas outlet of said second closed-loop refrigeration cycle, wherein said expander is operable reduce the pressure of at least a portion of said further cooled natural gas stream withdrawn from said second, closed-loop refrigeration cycle to thereby provide a two-phase fluid stream withdrawn via said low pressure outlet;
• a refrigerant compressor defining a suction port and a discharge port, wherein said suction port is in fluid flow communication with said low pressure outlet of said expander, wherein said refrigerant compressor is operable to compress at least a portion of said two-phase stream withdrawn from said low pressure outlet of said expander to thereby provide a compressed refrigerant stream withdrawn via said discharge port;
• and
• a refrigerant accumulator defining a second fluid inlet, a second vapor outlet, and a second liquid outlet, wherein said second fluid inlet of said refrigerant accumulator is in fluid flow communication with said discharge port of said refrigerant compressor, wherein said refrigerant accumulator is operable to separate at least a portion of said compressed refrigerant stream exiting said refrigerant compressor into a second predominantly vapor stream withdrawn from said second vapor outlet and a second predominantly liquid stream withdrawn from said second liquid outlet,
• wherein said second liquid outlet of said refrigerant accumulator is in fluid flow communication with said first reflux inlet of said heavies removal column.