Liquefied natural gas and hydrocarbon gas processing

A process for the separation of liquefied natural gas containing methane and heavier hydrocarbon components and a gas stream containing methane and heavier hydrocarbon components into a volatile residue gas fraction containing a major portion of said methane and a relatively less volatile liquid fraction containing a major portion of said heavier hydrocarbon components wherein

• (a) said liquefied natural gas is divided into at least a first liquid stream and a second liquid stream;
• (b) said first liquid stream is expanded to lower pressure and is thereafter supplied to a distillation column at an upper mid-column feed position;
• (c) said second liquid stream is heated sufficiently to vaporize it, thereby forming a vapor stream;
• (d) said vapor stream is expanded to said lower pressure and is supplied to said distillation column at a lower mid-column feed position;
• (e) said gas stream is divided into at least a first gaseous stream and a second gaseous stream;
• (f) said first gaseous stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
• (g) said expanded substantially condensed first gaseous stream is thereafter supplied to said distillation column at an additional upper mid-column feed position;
• (h) said second gaseous stream is expanded to said lower pressure, is cooled, and is thereafter supplied to said distillation column at an additional lower mid-column feed position;
• (i) an overhead distillation stream is withdrawn from an upper region of said distillation column and divided into at least a first portion and a second portion, whereupon said first portion is compressed to higher pressure;
• (j) said compressed first portion is cooled sufficiently to at least partially condense it and form thereby a condensed stream, with said cooling supplying at least a portion of said heating of said second liquid stream;
• (k) said condensed stream is divided into at least a volatile liquid stream and a reflux stream;
• (l) said reflux stream is further cooled, with said cooling supplying at least a portion of said heating of said second liquid stream;
• (m) said further cooled reflux stream is supplied to said distillation column at a top column feed position;
• (n) said volatile liquid stream is heated sufficiently to vaporize it, with said heating supplying at least a portion of said cooling of one or more of said first gaseous stream and said expanded second gaseous stream;
• (o) said second portion is heated, with said heating supplying at least a portion of said cooling of one or more of said first gaseous stream and said expanded second gaseous stream;
• (p) said vaporized volatile liquid stream and said heated second portion are combined to form said volatile residue gas fraction containing a major portion of said methane;
• and
• (q) the quantity and temperature of said reflux stream and the temperatures of said feeds to said distillation column are effective to maintain the overhead temperature of said distillation column at a temperature whereby the major portion of said heavier hydrocarbon components is recovered in said relatively less volatile liquid fraction by fractionation in said distillation column.