means of an internal distributor not shown located on top of the middle packed section 12 b the evenly distributed liquids continue flowing downward through the middle packed section 12 b wetting the packing internals and contacting the vapors flowing upward in so doing a distillation operation is established within the column 12 with the lighter more volatile components i e methane and nitrogen in the liquids being transferred into the vapor phase and the heavier less volatile components i e ethane and heavier hydrocarbons in the vapors being transferred into the liquid phase at the bottom of the middle packed section 12 b of column 12 a liquid draw off tray not shown is required liquids leaving from the bottom of middle packed section 12 b are collected in this draw off tray and exit column 12 the cryogenic fractionation column as stream 36 exchanger 34 the side reboiler heats and partially vaporizes stream 36 that is then fed back to column 12 as stream 37 entering onto the liquid distributor not shown for the bottom packed section 12 c the liquids from this distributor are evenly distributed over the bottom packed section 12 c and flow downward through the bottom packed section 12 c wetting the packing internals and contacting the vapors flowing upward in so doing a distillation operation is again established within the column 12.