Abstract: A process for separating the gas components contained in liquified natural gas wherein a small amount of heavier reflux liquid (propane, butane, pentane, iso-butane and iso-pentane) is recycled to the top of a demethanizer column. This alters its chemical equilibrium causing methane to vaporize in large quantities and to separate from the liquified feed stream. A fractionator receives the heavier demethanized liquid end product from the demethanizer column and through distillation separates the lighter ethanes and propanes from the heavier reflux liquid, a portion of the latter being recycled to the demethanizer column.

Abstract: A method for extracting natural gas liquids from a gas stream that has a high content of hydrogen and carbon dioxide is shown. This gas stream is scrubbed, dehydrated, filtered compressed and chilled prior to entering a demethanizer where the overhead residue gas consisting of hydrogen, nitrogen and methane are separated from the demethanizer bottoms product. Ths bottoms product is then warmed prior to entering a de-ethanizer where ethane, ethylene, and carbon dioxide are separated from the de-ethanizer bottoms product which consists of the heavier compounds of propylene, propane, butane, pentane and the like. The cold demethanizer residue gas is used to cool the incoming inlet gas stream via an inlet gas cooler, and expanded vapor from a high pressure separator is cross exchanged with the de-ethanizer overhead product stream.

Abstract: A process for separating natural gas constituents wherein a portion of the residue gas from the demethanizer column is cooled, expanded, partially condensed and recycled to the top of this column. This alters the chemical equilibrium in the column causing the lighter methane to vaporize and separate from the heavier constituents such as ethane, propane, etc. The lighter methane constituent rises and is removed from the top of the demethanizer column while the heavier constituents fall and are removed from the bottom of this column.